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Umhlaba Environmental Consulting~Prime Spot Trading 11 Pty Ltd~EIAReport~170317V01
Blast Management & Consulting Directors: JD Zeeman, MG Mthalane Page 1 of 94
Blast Management & Consulting
Quality Service on Time
Report: Blast Impact Assessment
Proposed Prime Spot Trading 11 (Pty) Ltd. Project Date: 17 March 2017
BM&C Ref No: Umhlaba Environmental Consulting~Prime Spot Trading 11 Pty
Ltd~EIAReport~170317V01
DMR Ref No: GP 10049 MR
Clienf Ref No: PS‐10049
Signed:
Name: JD Zeeman
Note: This document is the property of Blast Management & Consulting and should be treated as
confidential. No information in this document may be redistributed nor used at any other site than
the project it is intended for without prior consent from the author. The information presented is
given with the intention of assisting the receiver with optimized blast results and to ensure that a
safe and healthy blasting practice is conducted. Due to unforeseen rock formations that may
occur, neither the author nor his employees will assume liability for any alleged or actual damages
arising directly or indirectly out of the recommendations and information given in this document.
Umhlaba Environmental Consulting~Prime Spot Trading 11 Pty Ltd~EIAReport~170317V01
Blast Management & Consulting Directors: JD Zeeman, MG Mthalane Page 2 of 94
i. Document Prepared and Authorised by:
JD Zeeman
Blast Management & Consulting (2015/061002/07)
61 Sovereign Drive
Route 21 Corporate Park
Irene
South Africa
PO Box 61538
Pierre van Ryneveld
Centurion
0045
Cell: +27 82 854 2725 Tel: +27 (0)12 345 1445 Fax: +27 (0)12 345 1443
ii. Study Team Qualifications and Background
The study team comprises J D Zeeman (as the member of Blast Management & Consulting) and
Blast Management & Consulting employees. Blast Management & Consulting’s main areas of
concern are pre‐blast consultation and monitoring, insitu monitoring, post‐blast monitoring and
consulting as well as specialised projects. Blast Management & Consulting has been active in the
mining industry since 1997 and work has been done at various levels for mining companies in
South Africa, Botswana, Namibia, Mozambique, Democratic Republic of Congo, Sierra Leone and
Côte d'Ivoire.
J D Zeeman holds the following qualifications:
1985 ‐ 1987 Diploma: Explosives Technology, Technikon Pretoria
1990 ‐ 1992 BA Degree, University of Pretoria
1994 National Higher Diploma: Explosives Technology, Technikon Pretoria
1997 Project Management Certificate, Damelin College
2000 Advanced Certificate in Blasting, Technikon SA
Member: International Society of Explosive Engineers
iii. Independence Declaration
Blast Management & Consulting is an independent company. The work done for the report was
performed in an objective manner and according to national and international standards, which
means that the results and findings may not all be positive for the client. Blast Management &
Consulting has the required expertise to conduct such an investigation and draft the specialist
report relevant to the study. Blast Management & Consulting did not engage in any behaviour that
could be result in a conflict of interest in undertaking this study.
Umhlaba Environmental Consulting~Prime Spot Trading 11 Pty Ltd~EIAReport~170317V01
Blast Management & Consulting Directors: JD Zeeman, MG Mthalane Page 3 of 94
iv. Legal Requirements
In terms of the NEMA 2014 EIA Regulations contained in GN R982 of 04 December 2014 all
specialist studies must comply with Appendix 6 of the NEMA 2014 EIA Regulations (GN R982 of 04
December 2014). Table 1 show the requirements as indicated above.
Table 1: Legal Requirements for All Specialist Studies Conducted
Legal Requirement Relevant Section in Specialist study
(1) A specialist report prepared in terms of these Regulations
must contain‐
(a) details of‐
(i) the specialist who prepared the report; and i
(ii) the expertise of that specialist to compile a specialist
report including a curriculum vitae
Section ii and 23
(b) a declaration that the specialist is independent in a form as
may be specified by the competent authority;
Section iii
(c) an indication of the scope of, and the purpose for which, the
report was prepared;
Section 4
(d) the date and season of the site investigation and the relevance
of the season to the outcome of the assessment;
Section 8
(e) a description of the methodology adopted in preparing the
report or carrying out the specialised process
Section 6
(f) the specific identified sensitivity of the site related to the
activity and its associated structures and infrastructure;
Section 11
(g) an identification of any areas to be avoided, including buffers; Section 11
(h) a map superimposing the activity including the associated
structures and infrastructure on the environmental
sensitivities of the site including areas to be avoided, including
buffers;
Section 11 & 14
(i) a description of any assumptions made and any uncertainties
or gaps in knowledge;
Section 9
(j) a description of the findings and potential implications of such
findings on the impact of the proposed activity, including
identified alternatives on the environment;
Section 16
(k) any mitigation measures for inclusion in the EMPr; Section 16.11
(l) any conditions/aspects for inclusion in the environmental
authorisation;
Section 20
Umhlaba Environmental Consulting~Prime Spot Trading 11 Pty Ltd~EIAReport~170317V01
Blast Management & Consulting Directors: JD Zeeman, MG Mthalane Page 4 of 94
Legal Requirement Relevant Section in Specialist study
(m) any monitoring requirements for inclusion in the EMPr or
environmental authorisation;
Section 19
(n) a reasoned opinion (Environmental Impact Statement)‐ Section 22
as to whether the proposed activity or portions thereof should
be authorised; and
Section 22
if the opinion is that the proposed activity or portions thereof
should be authorised, any avoidance, management and
mitigation measures that should be included in the EMPr, and
where applicable, the closure plan;
Section 22
(o) a description of any consultation process that was undertaken
during the course of preparing the specialist report;
Section 12
(p) a summary and copies of any comments received during any
consultation process and where applicable all responses
thereto; and
Section 12
(q) any other information requested by the competent authority. None
v. Document Control:
Name & Company Responsibility Action Date Signature
C Zeeman
Blast Management &
Consulting
Document
Preparation
Report Prepared 17/03/2017
JD Zeeman
Blast Management &
Consulting
Consultant Report Finalise 17/03/2017
C Zeeman
Blast Management &
Consulting
Document
Preparation
POI added 5/04/2017
JD Zeeman
Blast Management &
Consulting
Consultant Report Finalise 5/04/2017
Umhlaba Environmental Consulting~Prime Spot Trading 11 Pty Ltd~EIAReport~170317V01
Blast Management & Consulting Directors: JD Zeeman, MG Mthalane Page 5 of 94
Table of Contents
1 Executive Summary.......................................................................................................... 11
2 Introduction ..................................................................................................................... 13
3 Objectives ........................................................................................................................ 14
4 Scope of blast impact study ............................................................................................. 14
5 Study area ........................................................................................................................ 15
6 Methodology ................................................................................................................... 17
7 Site Investigation ............................................................................................................. 18
8 Season applicable to the investigation ............................................................................. 18
9 Assumptions and Limitations ........................................................................................... 18
10 Legal Requirements ......................................................................................................... 19
11 Sensitivity of Project ........................................................................................................ 20
12 Consultation process ........................................................................................................ 23
13 Influence from blasting operations .................................................................................. 23
13.1 Ground vibration limitations on structures ........................................................................... 23
13.2 Ground vibration limitations and human perceptions .......................................................... 25
13.3 Air blast limitations on structures .......................................................................................... 26
13.4 Air blast limitations and human perceptions ......................................................................... 27
13.5 Fly rock ................................................................................................................................... 27
13.6 Noxious Fumes ....................................................................................................................... 29
14 Baseline Results ............................................................................................................... 29
14.1 Ground vibration and air blast predictions ............................................................................ 29
14.2 Structure profile ..................................................................................................................... 33
15 Construction Phase: Impact Assessment and Mitigation Measures .................................. 44
16 Operational Phase: Impact Assessment and Mitigation Measures ................................... 44
16.1 Review of expected ground vibration .................................................................................... 44
16.2 Summary of ground vibration levels ...................................................................................... 57
16.3 Ground Vibration and human perception.............................................................................. 58
16.4 Vibration impact on roads ...................................................................................................... 59
16.5 Potential that vibration will upset adjacent communities ..................................................... 59
16.6 Review of expected air blast .................................................................................................. 59
16.7 Summary of findings for air blast ........................................................................................... 73
16.8 Fly‐rock unsafe zone .............................................................................................................. 73
16.9 Noxious fumes ........................................................................................................................ 76
16.10 Potential Environmental Impact Assessment: Operational Phase ........................................ 76
16.11 Mitigations ............................................................................................................................. 81
17 Closure Phase: Impact Assessment and Mitigation Measures .......................................... 83
18 Alternatives (Comparison and Recommendation) ............................................................ 84
19 Monitoring ....................................................................................................................... 84
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20 Recommendations ........................................................................................................... 85
20.1 Regulatory requirements ....................................................................................................... 86
20.2 Graveyard ............................................................................................................................... 87
20.3 Blast Designs .......................................................................................................................... 87
20.4 Safe blasting distance and evacuation ................................................................................... 87
20.5 Road Closure .......................................................................................................................... 87
20.6 Recommended ground vibration and air blast levels ............................................................ 88
20.7 Blasting times ......................................................................................................................... 88
20.8 Photographic Inspections ....................................................................................................... 88
20.9 Third party monitoring ........................................................................................................... 90
21 Knowledge Gaps .............................................................................................................. 90
22 Conclusion ....................................................................................................................... 90
23 Curriculum Vitae of Author .............................................................................................. 92
24 References ....................................................................................................................... 94
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List of Acronyms used in this Report
a and b Site Constant
ANFO Ammonium nitrate fuel oil
APP Air Pressure Pulse
B Burden (m)
BH Blast Hole
BM&C Blast Management & Consulting
Bs Scaled Burden (m3/2kg‐1/2)
D Distance (m)
D Duration (s)
E East
E Explosive Mass (kg)
EIA Environmental Impact Assessment
Freq. Frequency
GRP Gas Release Pulse
I&AP Interested and Affected Parties
k Factor value
L Maximum Throw (m)
Lat/Lon
hddd°mm'ss.s"
Latitude/Longitude
Hours/degrees/minutes/seconds
M Charge Height
m (SH) Stemming height
M/S Magnitude/Severity
Mc Charge mass per metre column
N North
NE North East
NO Nitrogen Monoxide
NO2 Nitrogen Dioxide
NOx Nitrogen Oxide
NOx’s Noxious Fumes
NW North West
P Probability
POI Points of Interest
PPD Peak particle displacement
PPV Peak Particle Velocity
PVS Peak vector sum
RPP Rock Pressure Pulse
S Scale
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S South
SE South East
SH Stemming height (m)
SW South West
T Blasted Tonnage
TNT Explosives (Trinitrotoluene)
USBM United States Bureau of Mine
W West
WGS 84 Coordinates (South African)
WM With Mitigation Measures
WOM Without Mitigation Measures
List of Units used in this Report
% percentage
cm centimetre
dB decibel
dBL linear decibel
g acceleration
g/cm3 gram per cubic centimetre
Hz frequency
kg kilogram
kg/m3 kilogram per cubic metre
kg/t kilogram per tonne
km kilometre
kPa kilopascal
m metre
m2 metre squared
MJ Mega Joules
MJ/m³ Mega Joules per cubic meter
MJ/t Mega Joules per tonne
mm/s millimetres per second
mm/s2 millimetres per second square
ms milliseconds
Pa Pascal
ppm parts per million
psi pounds per square inch
θ theta or angle
Umhlaba Environmental Consulting~Prime Spot Trading 11 Pty Ltd~EIAReport~170317V01
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List of Figures
Figure 1: A visual indication of the location of the proposed mine covering 95 ha. ........................ 15
Figure 2: Mine Area with Infrastructure ............................................................................................ 17
Figure 3: Identified sensitive areas .................................................................................................... 22
Figure 4: USBM Analysis Graph .......................................................................................................... 24
Figure 5: USBM Analysis with Human Perception ............................................................................. 26
Figure 6: Schematic of fly rock terminology ...................................................................................... 28
Figure 7: Proposed prediction equations ........................................................................................... 32
Figure 8: Aerial view and surface plan of the proposed mining area with points of interest
identified ............................................................................................................................................ 34
Figure 9: Pit 2 minimum charge ground vibration evaluation ........................................................... 46
Figure 10: Pit 2 maximum charge ground vibration evaluation ........................................................ 49
Figure 11: Pit 3 minimum charge ground vibration evaluation ......................................................... 52
Figure 12: Pit 3 maximum charge ground vibration evaluation ........................................................ 55
Figure 13: The effect of ground vibration with human perception and vibration limits .................. 58
Figure 14: Pit 2 Minimum charge Air blast evaluation ...................................................................... 61
Figure 15: Pit 2 Maximum charge Air blast evaluation ...................................................................... 64
Figure 16: Pit 3 Minimum charge Air blast evaluation ...................................................................... 67
Figure 17: Pit 3 Maximum charge Air blast evaluation ...................................................................... 70
Figure 18: Fly rock prediction calculation .......................................................................................... 74
Figure 19: Predicted Fly rock Exclusion Zone for Pit 2 & Pit 3 ........................................................... 75
Figure 20: Structures identified where ground vibration mitigation will be required. ..................... 82
Figure 21: Monitoring Positions suggested for the Quarry. .............................................................. 85
Figure 22: Regulatory 500 m range for the Quarry ........................................................................... 86
Figure 23: Photographic inspection area and POI’s ........................................................................... 89
List of Tables
Table 1: Legal Requirements for All Specialist Studies Conducted ...................................................... 3
Table 2: Damage Limits for Air Blast .................................................................................................. 27
Table 3: Blast design technical information ....................................................................................... 30
Table 4: POI Classification used ......................................................................................................... 33
Table 5: List of points of interest identified (WGS – LO 29ᵒ) ............................................................. 35
Table 6: Structure Profile ................................................................................................................... 36
Table 7: Pit 2 minimum charge ground vibration evaluation ............................................................ 47
Table 8: Pit 2 maximum charge ground vibration evaluation ........................................................... 50
Table 9: Pit 3 minimum charge ground vibration evaluation ............................................................ 53
Table 10: Pit 3 maximum charge ground vibration evaluation ......................................................... 56
Table 11: Pit 2 Minimum charge Air blast evaluation ........................................................................ 62
Table 12: Pit 2 Maximum charge Air blast evaluation ....................................................................... 65
Umhlaba Environmental Consulting~Prime Spot Trading 11 Pty Ltd~EIAReport~170317V01
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Table 13: Pit 3 Minimum charge Air blast evaluation ........................................................................ 68
Table 14: Pit 3 Maximum charge Air blast evaluation ....................................................................... 71
Table 15: Fly rock concern POI’s ........................................................................................................ 76
Table 16: Evaluation matrix criteria ................................................................................................... 76
Table 17: Risk assessment outcome before mitigation ..................................................................... 78
Table 18: Risk assessment outcome after mitigation ........................................................................ 79
Table 19: Structures at the Quarry Area identified as problematic .................................................. 81
Table 20: Mitigation measures for ground vibration ......................................................................... 83
Table 21: List of possible monitoring positions ................................................................................. 85
Table 22: List of possible installations within regulatory 500 m ....................................................... 86
Table 23: Recommended ground vibration air blast limits ............................................................... 88
Table 24: Recommended POI’s for photographic inspections .......................................................... 89
Umhlaba Environmental Consulting~Prime Spot Trading 11 Pty Ltd~EIAReport~170317V01
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1 Executive Summary
Blast Management & Consulting (BM&C) was contracted as part of the Environmental Impact
Assessment (EIA) to perform an initial review of possible impacts with regards to blasting
operations in the proposed Prime Spot Trading 11 (Pty) Ltd. Project located approximately 25km
south‐east of the town of Vereeniging in the Gauteng Province, South Africa at coordinates
(Lat/Lon WGS84) 26°45'56.85"S 28° 2'51.13"E. Ground vibration, air blast, fly rock and fumes are
some of the aspects resulting from blasting operations. The report concentrates on the possible
influences of ground vibration, air blast and fly rock. It intends to provide information,
calculations, predictions, possible influences and mitigation of blasting operations for this project.
The project area has limited installations where people congregate or being present in the vicinity.
The nearest installations are two graveyards inside the quarry boundary and the Rand Water
Board canal towards the western side of the quarry area.
The graveyards are of greatest concern for this project. One graveyard is located between Pit 2
and Pit 3 and the second south east of Pit 2. The levels of ground vibration from normal blasting
ate both graveyards are greater than allowed limits. Mitigation on blasting will be required for
both graveyards regarding ground vibration. Pit 2 is closest to both and will required reduced
charge mass per delay to mitigate ground vibration. Pit 3 is located further away and less
mitigation will be required. Mitigation measures were provided that can be followed.
The Rand Water Servitude which includes a canal and pipelines was also considered a sensitive
installation. The ground vibration levels predicted for the Rand Water Servitude were well within
the limits proposed and not expected to be in danger of induced damage due to ground vibration.
Considering fly rock there are no other structures or installations that should be considered other
than the grave yard. Stemming will be needed to ensure that fly rock is limited as best possible.
There are also regulations that will need to be followed for permission to conduct blasting
operations with these installations within 500 m from the blast operations.
Air blast predicted for the maximum charge ranges were well within accepted norms for private
installations surrounding the quarry area. No specific concerns were noted due to air blast levels
predicted.
An exclusion zone for safe blasting was also calculated. The exclusion zone was established to be
at least 237 m. Normal practice observed in mines is a 500 m exclusion zone.
Umhlaba Environmental Consulting~Prime Spot Trading 11 Pty Ltd~EIAReport~170317V01
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Recommendations were made that should be considered, specifically for review of blast designs,
monitoring of ground vibration and air blast, safe blasting zones, safe ground vibration and air
blast limits, relocation of households, structure inspections and blasting times.
This concludes this investigation for the Prime Spot Trading 11 (Pty) Ltd. Project. There is no
reason to believe that this operation cannot continue if attention is given to the recommendations
made.
Umhlaba Environmental Consulting~Prime Spot Trading 11 Pty Ltd~EIAReport~170317V01
Blast Management & Consulting Directors: JD Zeeman, MG Mthalane Page 13 of 94
2 Introduction
The application area is located approximately 25km south‐east of the town of Vereeniging in the
Gauteng Province, South Africa at coordinates (Lat/Lon WGS84) 26°45'56.85"S 28° 2'51.13"E.
Prime Spot Trading 11 (Pty) Ltd. has applied for a mining right & associated waste management
licence over a portion of portion 1 of the Farm Vischgat 467IR and is located in the vicinity of
Vereeniging in the Gauteng province of South Africa.
Mining activities will involve the removal of dimension stone, aggregate & stone aggregate from a
quarry pit. Mining will initially commence from the existing defunct pit.
Mining activities will typically include:
Vegetation and topsoil removal: Due to existing disturbed areas (associated with historic
mining activities) there will be minimal removal of vegetation and topsoil. When mining
progresses onto undisturbed ground vegetation and topsoil will be stripped and stored in
berms to expose the overburden.
Overburden removal: Overburden (decomposed material above the hard rock). In order to
expose the rock, the overburden requires removal. Where possible, overburden will be
removed by mechanical digging using an excavator. If the material is too hard,
conventional drilling & blasting methods will be used. Once loosened the overburden
material will either be sold as fill material (preferred) or be transported to overburden
dumps by haul trucks.
Drilling & blasting: The minerals reserves; dimension stone, aggregate, stone aggregate will
be loosened by conventional drilling & blasting. The frequency of drilling & blasting will
depend on market demand. Explosives will be delivered to the benches as & when
required. Blasting aims to fragment rock to size suitable for processing through the plants.
Where this is not achieved, larger boulders will be broken up using a hydraulic hammer.
As part of Environmental Impact Assessment (EIA), Blast Management & Consulting (BM&C) was
contracted to perform a review of possible impacts from blasting operations for the proposed
quarry. Ground vibration, air blast and fly rock are some of the aspects that result from blasting
operations and this study considers the possible influences that blasting may have on the
surrounding area in this respect. The report concentrates on ground vibration and air blast and
intends to provide information, calculations, predictions, possible influences and mitigating
aspects of blasting operations for the project.
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3 Objectives
The objectives of this document are: outlining the expected environmental effects that blasting
operations at the Prime Spot Trading 11 (Pty) Ltd. Quarry may have on the surrounding
environment; proposing the specific mitigation measures that will be required. This study
investigates the related influences of expected ground vibration, air blast and fly rock. These
effects are investigated in relation to the blast site area and surrounds and the possible influence
on nearby private installations, houses and the owners or occupants.
The objectives were dealt with whilst taking specific protocols into consideration. The protocols
applied in this document are based on the author’s experience, guidelines taken from literature
research, client requirements and general indicators in the various appropriate pieces of South
African legislation. There is no direct reference in the following acts to requirements and limits on
the effect of ground vibration and air blast and some of the aspects addressed in this report:
• National Environmental Management Act No. 107 of 1998
• Mine Health and Safety Act No. 29 of 1996
• Mineral and Petroleum Resources Development Act No. 28 of 2002
• Explosives Act No. 15 of 2003.
The guidelines and safe blasting criteria are based on internationally accepted standards and
specifically criteria for safe blasting for ground vibration and recommendations on air blast
published by the United States Bureau of Mines (USBM). There are no specific South African
standards and the USBM is well accepted as standard for South Africa.
4 Scope of blast impact study
The scope of the study is determined by the terms of reference to achieve the objectives. The
terms of reference can be summarised according to the following steps taken as part of the EIA
study with regards to ground vibration, air blast and fly rock due to blasting operations.
Background information of the proposed site
Blasting Operation Requirements
Site specific evaluation of blasting operations according to the following:
o Evaluation of expected ground vibration levels from blasting operations at specific
distances and on structures in surrounding areas
o Evaluation of expected ground vibration influence on neighbouring communities
o Evaluation of expected blasting influence on national and provincial roads surrounding
the blasting operations if present
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o Evaluation of expected ground vibration levels on water boreholes if present within 500
m from blasting operations
o Evaluation of expected air blast levels at specific distances from the operations and
possible influence on structures
o Evaluation of fly rock unsafe zone
o Discussion on the occurrence of noxious fumes and dangers of fumes
o Evaluation of the location of blasting operations in relation to surrounding areas
according to the regulations from the applicable Acts
Impact Assessment
Mitigations
Recommendations
Conclusion
5 Study area
The application area is located approximately 25km south‐east of the town of Vereeniging in the
Gauteng Province, South Africa at coordinates (Lat/Lon WGS84) 26°45'56.85"S 28° 2'51.13"E.
Figure 1 shows a visual indication of the location of the proposed mine covering 95 ha. Figure 2
shows a view of the proposed layout for the mining area with indication of the quarry specifically.
Figure 1: A visual indication of the location of the proposed mine covering 95 ha.
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Figure 2: Mine Area with Infrastructure
6 Methodology
The detailed plan of study consists of the following sections.
• Base line influence: Determine if the project evaluated is part of existing operations
with blasting activities currently being done or no operations yet. If operational then
baseline monitoring is done. If not the baseline is zero with no specific influence from
blasting.
• Identifying surface structures / installations that are found within reason from project
site. A list of Point of Interests (POI’s) are created that will be used for evaluation.
• Site evaluation: This consists of evaluation of the planned mining drilling and blasting
operations and the possible influences from the blasting operations. The methodology
includes modelling the expected impact based on the expected drilling and blasting
information provided for the project. Various accepted mathematical equations are
applied to determine the attenuation of ground vibration, air blast and fly rock. These
values are then calculated over the distance investigated from site and shown as
amplitude level contours. Overlaying these contours on the location of the various
receptors then gives an indication of the possible impacts and the expected results of
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potential impacts. Evaluation of each receptor according to the predicted levels then
gives an indication of the possible mitigation measures to be applied. The possible
environmental or social impacts are then addressed in the detailed EIA phase
investigation.
• Reporting: All data is prepared in a single report and provided for review.
7 Site Investigation
The site was visited and specific structure identification was done on 20 February 2017. This site
visit was done specifically to get understanding of the location of the quarry area for the project
and identifying the structures and installations surrounding the proposed new quarry.
8 Season applicable to the investigation
The drilling and blasting operations are not season dependable. The investigation into the possible
effects from blasting operations is not season bounded.
9 Assumptions and Limitations
Mining activities will involve the removal of dimension stone, aggregate & stone aggregate from a
quarry pit. Mining will initially commence from the existing defunct pit.
Mining activities will typically include:
Vegetation and topsoil removal: Due to existing disturbed areas (associated with historic
mining activities) there will be minimal removal of vegetation and topsoil. When mining
progresses onto undisturbed ground vegetation and topsoil will be stripped and stored in
berms to expose the overburden.
Overburden removal: Overburden (decomposed material above the hard rock). In order to
expose the rock, the overburden requires removal. Where possible, overburden will be
removed by mechanical digging using an excavator. If the material is too hard,
conventional drilling & blasting methods will be used. Once loosened the overburden
material will either be sold as fill material (preferred) or be transported to overburden
dumps by haul trucks.
Drilling & blasting: The minerals reserves; dimension stone, aggregate, stone aggregate will be
loosened by conventional drilling & blasting. The frequency of drilling & blasting will depend on
market demand. Explosives will be delivered to the benches as & when required. Blasting aims to
fragment rock to size suitable for processing through the plants. Where this is not achieved, larger
boulders will be broken up using a hydraulic hammer.
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The anticipated levels of influence estimated in this report are calculated using standard accepted
methodology according to international and local regulations. Assumption is made that the
predictions are a good estimate with significant safety factors to ensure that expected levels are
based on worst case scenarios. These will have to be confirmed with actual measurements once
the operation is active.
10 Legal Requirements
The protocols applied in this document are based on the author’s experience, guidelines elicited
by the literature research, client requirements and general indicators provided in the various
applicable South African acts. There is no direct reference in the consulted acts specifically with
regard to limiting levels for ground vibration and air blast. There is however specific requirements
and regulations with regards to blasting operations and the effect of ground vibration and air blast
and some of the aspects addressed in this report. The acts consulted are: National Environmental
Management Act No. 107 of 1998; Mine Health and Safety Act No. 29 of 1996; Mineral and
Petroleum Resources Development Act No. 28 of 2002; and the Explosives Act Explosives Act No.
15 of 2003.
The guidelines and safe blasting criteria applied in this study are as per internationally accepted
standards, and specifically the United States Bureau of Mines (USBM) criteria for safe blasting for
ground vibration and the recommendations on air blast. There are no specific South African
standards and the USBM is well accepted as standard for South Africa. Additional criteria required
by various institutions in South Africa were also taken into consideration, i.e. Eskom, Telkom,
Transnet, Rand Water Board, etc.
In view of the acts consulted the following guidelines and regulations are noted: (where possible
detail was omitted and only some of the information indicated)
MINE HEALTH AND SAFETY ACT 29 OF 1996
(Gazette No.17242, Notice No. 967 dated 14 June 1996. Commencement date: 15 January 1997 for all sections
with the exception of sections 86(2) and (3), which came into operation on 15 January 1998, [Proc.No.4, Gazette
No. 17725])
MINE HEALTH AND SAFETY REGULATIONS
Precautionary measures before initiating explosive charges
4.7 The employer must take reasonable measures to ensure that when blasting takes place, air and ground
vibrations, shock waves and fly material are limited to such an extent and at such a distance from any building,
public thoroughfare, railway, power line or any place where persons congregate to ensure that there is no
significant risk to the health or safety of persons.
General precautions
4.16 The employer must take reasonable measures to ensure that:
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4.16(1) in any mine other than a coal mine, no explosive charges are initiated during the shift unless –
(a) such explosive charges are necessary for the purpose of secondary blasting or reinitiating the misfired holes in
development faces;
(b) written permission for such initiation has been granted by a person authorised to do so by the employer; and
(c) reasonable precautions have been taken to prevent, as far as possible, any person from being exposed to
smoke or fumes from such initiation of explosive charges;
4.16(2) no blasting operations are carried out within a horizontal distance of 500 metres of any public building,
public thoroughfare, railway line, power line, any place where people congregate or any other structure, which it
may be necessary to protect in order to prevent any significant risk, unless:
(a) a risk assessment has identified a lesser safe distance and any restrictions and conditions to be complied with;
(b) a copy of the risk assessment, restrictions and conditions contemplated, in paragraph (a) have been provided
for approval to the Principal Inspector of Mines;
(c) shot holes written permission has been granted by the Principal Inspector of Mines; and
(d) any restrictions and conditions determined by the Principal inspector of Mines are complied with.
MINERAL AND PETROLEUM RESOURCES DEVELOPMENT ACT 28 OF 2002 (Gazette No. 23922, Notice No. 1273 dated 10 October 2002. Commencement date: 1 May 2004 [Proc. No. R25,
Gazette No. 26264])
MINERAL AND PETROLEUM RESOURCES DEVELOPMENT REGULATIONS
67. Blasting, vibration and shock management and control (1) A holder of a right or permit in terms of the Act must comply with the provisions of the Mine Health and Safety
Act, 1996, (Act No. 29 of 1996), as well as other applicable law regarding blasting, vibration and shock
management and control.
(2) An assessment of impacts relating to blasting, vibration and shock management and control, where applicable,
must form part of the environmental impact assessment report and environmental management programme or
the environmental management plan, as the case may be.
11 Sensitivity of Project
A review of the project and the surrounding areas is done before any specific analysis is
undertaken and sensitivity mapping is done, based on typical areas and distance from the
proposed quarry area. This sensitivity map uses distances normally associated where possible
influences may occur and where influence is expected to be very low or none. Three different
areas were identified in this regard:
• A highly sensitive area of 500 m around the mining area. Normally, this 500 m area is
considered an area that should be cleared of all people and animals prior to blasting.
Levels of ground vibration and air blast are also expected to be higher closer to the
quarry area.
• An area 500 m to 1500 m around the quarry area can be considered as being a medium
sensitive area. In this area, the possibility of impact is still expected, but it is lower. The
expected level of influence may be low, but there may still be reason for concern, as
levels could be low enough not to cause structural damage but still upset people.
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• An area greater than 1500 m is considered low sensitivity area. In this area it is
relatively certain that influences will be low with low possibility of damages and limited
possibility to upset people.
Figure 3 shows the sensitivity mapping with the identified points of interest (POI) in the
surrounding areas for the proposed Prime Spot Trading 11 (Pty) Ltd. project. The specific
influences will be determined through the work done for this project in this report.
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Figure 3: Identified sensitive areas
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12 Consultation process
No specific consultation with external parties was utilised. The work done is based on the author’s
knowledge, baseline work at client’s operations and information provided by the client.
13 Influence from blasting operations
Blasting operations are required to break rock for excavation to access the targeted ore material.
Explosives in blast holes provide the required energy to conduct the work. Ground vibration, air
blast and fly rock are a result from the blasting process. Based on the regulations of the different
acts consulted and international accepted standards these effects are required to be within certain
limits. The following sections provide guidelines on these limits. As indicated there are no specific
South African ground vibration and air blast limit standards.
13.1 Ground vibration limitations on structures
Ground vibration is measured in velocity with units of millimetres per second (mm/s). Ground
vibration can also be reported in units of acceleration or displacement if required. Different types
of structures have different tolerances to ground vibration. A steel structure or a concrete
structure will have a higher resistance to vibrations than a well‐built brick and mortar house. A
brick and mortar house will be more resistant to vibrations than a poorly constructed or a
traditional built mud house. Different limits are then applicable to the different types of
structures. Limitations on ground vibration take the form of maximum allowable levels or
intensity for different installations or structures. Ground vibration limits are also dependent on
the frequency of the ground vibration. Frequency is the rate at which the vibration oscillates.
Faster oscillation is synonym with higher frequency and lower oscillation is synonym with lower
frequency. Lower frequencies are less acceptable than higher frequencies because structures
have a low natural frequency. Significant ground vibration at low frequencies could cause
increased structure vibrations due to the natural low frequency of the structure and this may lead
to crack formation or damages to occur.
Currently, the USBM criteria for safe blasting are applied as the industry standard where private
structures are of concern. Ground vibration amplitude and frequency is recorded an analysed. The
data is then evaluated accordingly. The USBM graph is used for plotting of data and evaluating the
data. Figure 4 below provides a graphic representation of the USBM analysis for safe ground
vibration levels. The USBM graph is divided mainly into two parts. The red lines in the figure are
the USBM criteria:
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Analysed data displayed in the bottom half of the graph shows safe ground vibration levels,
Analysed data displayed in the top half of the graph shows potentially unsafe ground
vibration levels:
Added to the USBM graph is a blue line and green dotted line that represents 6 mm/s and 12.5
mm/s additional criteria that are used by BM&C.
Figure 4: USBM Analysis Graph
Additional limitations that should be considered were determined through research and
prescribed by the various institutions; these are as follows:
National roads/tar roads: 150 mm/s
Steel pipelines: 50 mm/s (Rand Water Board)
Water Canal: 25 mm/s (Rand Water Board)
Electrical lines: 75 mm/s (Eskom)
Sasol Pipe Lines: 25 mms/s (Sasol)
Railways: 150 mm/s
Concrete less than 3 days old: 5 mm/s
Concrete after 10 days: 200 mm/s
Sensitive plant equipment: 12 mm/s or 25 mm/s, depending on type. (Some switches could
trip at levels of less than 25 mm/s.)
6 6
12.5 12.5
0.1
1
10
100
1000
1 10 100
Ground Vibration (mm/s)
Frequency (Hz)
Prime Spot 11 Pty Ltd. ProjectUSBM Graph and BM&C Ground Vibration Limits
Safe Blasting Zone
Above Limit Zone
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Waterwells: 50 mm/s
Considering the above limitations, BM&C work is based on the following:
USBM criteria for safe blasting.
The additional limits provided above.
Consideration of private structures in the area of influence.
Should structures be in poor condition the basic limit of 25 mm/s is halved to 12.5 mm/s or
when structures are in very poor condition limits will be restricted to 6 mm/s. It is a
standard accepted method to reduce the limit allowed with poorer condition of structures.
Traditional built mud houses are limited to 6 mm/s. The 6 mm/s limit is used due to
unknowns on how these structures will react to blasting. There is also no specific scientific
data available that would indicate otherwise.
Input from other consultants in the field locally and internationally.
13.2 Ground vibration limitations and human perceptions
A further aspect of ground vibration and frequency of vibration that must be considered is human
perceptions. It should be realized that the legal limit set for structures is significantly greater than
the comfort zone of human beings. Humans and animals are sensitive to ground vibration and the
vibration of structures. Research has shown that humans will respond to different levels of
ground vibration at different frequencies.
Ground vibration is experienced at different levels; BM&C considers only the levels that are
experienced as “Perceptible”, “Unpleasant” and “Intolerable”. This is indicative of the human
being’s perceptions of ground vibration and clearly indicates that humans are sensitive to ground
vibration and humans perceive ground vibration levels of 4.5 mm/s as unpleasant (See Figure 5).
This guideline helps with managing ground vibration and the complaints that could be received
due to blast induced ground vibration.
Indicated on Figure 5 is blue solid line that indicates a ground vibration level of 12.5 mm/s and a
green dotted line that indicates a ground vibration level of 6 mm/s. These are levels that are used
in evaluation.
Generally, people also assume that any vibration of a structure ‐ windows or roofs rattling ‐ will
cause damage to the structure. Air blast is one of the causes of vibration of a structure and is the
cause of nine out of ten complaints.
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Figure 5: USBM Analysis with Human Perception
13.3 Air blast limitations on structures
Air blast or air‐overpressure is a pressure wave generated from the blasting process. Air blast is
measured as a pressure in pascal (Pa) and reported as a decibel value (dBL). Air blast is normally
associated with frequency levels less than 20 Hz, which is at the threshold for hearing. Air blast
can be influenced by meteorological conditions, the final blast layout, timing, stemming,
accessories used, blast covered by a layer of soil or not etc. Air blast should not be confused with
sound that is within the audible range (detected by the human ear). A blast does generate sound
as well but for the purpose of possible damage capability we are only concerned with air blast in
this report. The three main causes of air blasts can be observed as:
Direct rock displacement at the blast; the air pressure pulse (APP)
Vibrating ground some distance away from the blast; rock pressure pulse (RPP)
Venting of blast holes or blowouts; the gas release pulse (GRP)
The general recommended limit for air blast currently applied in South Africa is 134dB. This is
based on work done by the USBM. The USBM also indicates that the level is reduced to 128 dB in
proximity of hospitals, schools and sensitive areas where people congregate. Based on work
carried out by Siskind et al. (1980), monitored air blast amplitudes up to 135dB are safe for
structures, provided the monitoring instrument is sensitive to low frequencies. Persson et al.
(1994) have published estimates of damage thresholds based on empirical data (Table 2). Levels
6 6
12.5 12.5
0.1
1
10
100
1000
1 10 100
Ground Vibration (mm/s)
Frequency (Hz)
Prime Spot 11 Pty Ltd. ProjectGround Vibration Limits & Human Perception
Perceptible
Unpleasant
Intolerable
Safe Blasting Zone
Above Limit Zone
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given in Table 2 are at the point of measurement. The weakest points on a structure are the
windows and ceilings.
Table 2: Damage Limits for Air Blast
Level Description
>130 dB Resonant response of large surfaces (roofs, ceilings). Complaints start.
150 dB Some windows break
170 dB Most windows break
180 dB Structural Damage
All attempts should be made to keep air blast levels from blasting operations well below 120dB
where the public is of concern.
13.4 Air blast limitations and human perceptions
Considering human perceptions and the misunderstanding about ground vibration and air blast,
BM&C generally recommends that blasting be done in such a way that air blast levels are kept
below 120dB. This will ensure fewer complaints regarding blasting operations due to the effect on
structures (like rattling windows, doors or a large roof surface) that startle people will also be
reduced. These effects are sometimes erroneously identified as ground vibration and considered
to be damaging to the structure.
In this report initial limits for evaluating conditions have been set at 120dB, 120 dB to 134dB and
greater than 134dB. The USBM limits for nuisance is 134dB.
13.5 Fly rock
Blasting practices require some movement of rock to facilitate the excavation process. The extent
of movement is dependent on the scale and type of operation. For example, blasting activities at
large coal mines are designed to cast the blasted material over a greater distance than in quarries
or hard rock operations or a quarry as in this project. The movement should be in the direction of
the free face. In a quarry situation the free face is the surface. The orientation of the blast and
expected movement direction is important. Material or elements travelling outside of a planned
or expected range would be considered fly rock. Figure 6 shows schematic of fly rock definitions.
Fly rock can be categorised as follows:
Throw ‐ the planned forward movement of rock fragments that form the muck pile within
the blast zone.
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Fly rock ‐ the undesired propulsion of rock fragments through the air or along the ground
beyond the blast zone by the force of the explosion that is contained within the blast
clearance (exclusion) zone. When using this definition, fly rock, while undesirable, is only a
safety hazard if a breach of the blast clearance (exclusion) zone occurs.
Wild fly rock ‐ the unexpected propulsion of rock fragments that travels beyond the blast
clearance (exclusion) zone when there is some abnormality in a blast or a rock mass.
Figure 6: Schematic of fly rock terminology
Fly rock from blasting can result under the following conditions:
When burdens are too small, rock elements can be propelled out of the free face area of
the blast,
When burdens are too large and movement of blast material is restricted and stemming
length is not correct, rock elements can be forced upwards creating a crater forming fly
rock,
If the stemming material is of poor quality or too little stemming material is applied, the
stemming is ejected out of the blast hole, which can result in fly rock.
Stemming of correct type and length is required to ensure that explosive energy is efficiently used
to its maximum and to control fly rock.
The occurrence of fly rock in any form will have impact if found to travel outside the safe
boundary. If a road or structure or people or animals are within the safe boundary of a blast,
irrespective of the possibility of fly rock or not, precautions should be taken to stop the traffic,
remove people or animals for the period of the blast. The fact is that fly rock will cause damage to
the road, vehicles or even death to people or animals. This safe boundary is determined by the
appointed blaster or as per mine code of practice. BM&C uses a prediction calculation defined by
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the International Society of Explosives Engineers (ISEE) to assist with determining minimum
distance.
13.6 Noxious Fumes
Explosives used in mining environment are required to be oxygen balanced. Oxygen balance
refers to the stoichiometry of the chemical reaction and the nature of gases produced from the
detonation of the explosives. The creation of poisonous fumes such as nitrous oxides and carbon
monoxide are particularly undesirable. These fumes present themselves as red brown cloud after
the blast has detonated. It has been reported that 10ppm to 20ppm can be mildly irritating.
Exposure to 150 ppm or more (no time period given) has been reported to cause death from
pulmonary edema. It has been predicted that 50% lethality would occur following exposure to
174ppm for 1 hour. Anybody exposed must be taken to hospital for proper treatment.
Factors contributing to undesirable fumes are typically: poor quality control on explosive
manufacture, damage to explosive, lack of confinement, insufficient charge diameter, excessive
sleep time, water in blast holes incorrect product used or product not loaded properly and specific
types of rock/geology can also contribute to fumes.
14 Baseline Results
Base line work for this report normally consists of two parts. The first part is the monitoring of
blasting operations to establish criteria for prediction of ground vibration and air blast if and when
blasting is done. The project is not currently active with no blasting operations being done. There
has been blasting done previously. No specific monitoring was done. Baseline data is considered at
zero level. The second part of baseline work done is familiarising oneself with the surroundings
and the typical structures that are found in the area of the project. The information for this is
presented below.
14.1 Ground vibration and air blast predictions
Explosives are used to break rock through the shock waves and gasses yielded from the explosion.
Ground vibration and air blast is a result from blasting activities. Factors influencing ground
vibration are the charge mass per delay, distance from the blast, the delay period and the
geometry of the blast. These factors are controlled by planned design and proper blast
preparation.
An aspect that is not normally considered as pre‐operation definable is the effect of air blast. This
is mainly due to the fact that air blast is an aspect that can be controlled to a great degree by
applying basic rules. Air blast is the direct result from the blast process, although influenced by
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meteorological conditions, the final blast layout, timing, stemming length, stemming material,
accessories used, covered blast or not covered blast etc. all has an influence on the outcome of
the result.
This project is a new planned operation with no specific blast designs available. A typical design
was done for the development of the quarry in order to access the underground resource.
Part of the baseline work is monitoring of existing blasting where possible. The quarry is not
currently operational. Information from original blasting done when quarry was started was
applied as guideline for blast design input. Table 3 shows the technical information for the design
done.
Table 3: Blast design technical information
Type of Blast: Primary
Bench Height (m): 10.0
B/H Depth ‐ Min (m): 11.0
B/H Depth ‐ Max (m): 11.0
B/H Diameter (mm): 89
Sub Drill Length (m): 0
Burden (m): 2.0
Spacing (m): 2.5
Drill Pattern: Square
Quantity Blast Holes: 221
Explosive Type: HEF100
Cup Density (kg/m3): 1.05
In‐hole Density (kg/m3): 1.15
Charge per b/h ‐ Min (kg): 75
Charge per b/h ‐ Max (kg): 75
Charge Length ‐ Min (m): 9.0
Charge Length ‐ Max (m): 9.0
Stemming Length ‐ Min (m): 2.0
Stemming Length ‐ Max (m): 2.0
Type of Stemming: Aggregate 13 mm
Accessories Type: BME
Down hole Timing (ms): 350
Surface Timing ‐ I/H (ms): 17
Surface Timing ‐ I/R (ms): 42
Booster / Primer: 150
Delay Pattern: N/A
Charge per delay (kg/delay): 450
Powder Factor (kg/m3): 1.220
Free Face: Yes
Max. No. of Decks / Blast hole: 1
When applying shock tube type initiation and timing it is expected that up to 6 blast holes could
detonate simultaneously. Evaluation of the blasting operations considered a minimum charge and
a maximum charge for evaluation of expected ground vibration and air blast effects. A minimum
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and maximum charge is evaluated. The minimum charge was derived from the charge of a single
89 mm diameter blasthole – 75 kg and the maximum charge relates to 6 times the single charge ‐
450 kg. These values were applied in all predictions for ground vibration and air blast.
When predicting ground vibration and possible decay, a standard accepted mathematical process
of scaled distance is used. The equation applied (Equation 1) uses the charge mass and distance
with two site constants. In the absence of testing or monitoring standard constants are applied.
These constants are applied in equation 1 below.
Equation 1:
√
Where:
PPV = Predicted ground vibration (mm/s)
a = Site constant
b = Site constant
D = Distance (m)
E = Explosive Mass (kg)
General factors applied for the constants a & b are:
a = 1143 and
b = ‐1.65.
Utilizing the abovementioned equation and the given factors, allowable levels for specific limits
and expected ground vibration levels can then be calculated for various distances. Predicting the
outcome of air blast is considered difficult in most circumstances. There are many variables that
have influence on the outcome of air blast. In most cases mainly an indication of typical levels can
be obtained.
A standard cube root scaling prediction formula is applied for air blast predictions. The following
Equation 2 was used to calculate possible air blast values in millibar. This equation does not take
temperature or any weather conditions into account.
Equation 2:
P AxD
E
Where:
= Air blast level (mB)
D = Distance from source (m)
E = Maximum charge mass per delay (kg)
A = Constant
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‐B = Constant
The constants for A and B were then selected according to the information as provided in Figure 7
below. Various types of mining operations are expected to yield different results. The information
provided in Figure 7 is based on detailed research that was conduct for each of the different types
of mining environments. In this report the data for Quarry face was applied in the prediction or air
blast – constants of 37.1 (A) and ‐0.97 (B) was applied.
Figure 7: Proposed prediction equations
The air pressure calculated in Equation 2 is converted to decibels in Equation 3. The reporting of
air blast in the decibel scale is more readily accepted in the mining industry.
Equation 3:
p 20xlog
Where:
p = Air blast level (dB)
= Air blast level (Pa (mB x 100))
= Reference Pressure (2 x 10‐5 Pa)
Although the above equation was applied for prediction of air blast levels, additional measures are
also recommended in order to ensure that air blast and associated fly‐rock possibilities are
minimized as best possible.
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14.2 Structure profile
As part of the baseline, all possible structures in a possible influence area are identified. The site
review is detailed here. The site was reviewed using Google Earth imagery. Information sought
during the review was to identify surface structures present in a 3500 m radius from the proposed
mine boundary (the quarry), which will require consideration during modelling of blasting
operations, e.g. houses, general structures, power lines, pipe lines, reservoirs, mining activity,
roads, shops, schools, gathering places, possible historical sites, etc. A list was prepared of all
structures in the vicinity of the Prime Spot Trading 11 (Pty) Ltd. Project area. The list includes
structures and points of interest (POI) within the 3500 m boundary – see Table 4 below. A list of
structure locations was required in order to determine the allowable ground vibration limits and
air blast limits. Figure 8 shows an aerial view of the quarry area and surroundings with POIs. The
type of POIs identified is grouped into different classes. These classes are indicated as
“Classification” in Table 5. The classification used is a BM&C classification and does not relate to
any standard or national or international code or practice. Table 4 shows the descriptions for the
classifications used.
Table 4: POI Classification used
Class Description
1 Rural Building and structures of poor construction
2 Private Houses and people sensitive areas
3 Office and High rise buildings
4 Animal related installations and animal sensitive areas
5 Industrial buildings and installations
6 Earth like structures – no surface structure
7 Graves & Heritage
8 Water Borehole
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Figure 8: Aerial view and surface plan of the proposed mining area with points of interest identified
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Table 5: List of points of interest identified (WGS – LO 29ᵒ)
Tag Description Classification Y X
1 Farm Animal Related Structures (Kanhym Estates) 4 96140.73 2959538.35
2 Chicken Broilers Animal Related Structures 4 95897.54 2959816.91
3 Dam 5 96646.70 2959312.92
4 Buildings/Structures 2 96967.62 2958893.93
5 Farm Animal Related Structures 4 96211.41 2959261.28
6 Sand Works 5 97386.78 2959998.17
7 Buildings/Structures 2 97215.41 2959728.05
8 Dam 5 97549.16 2959950.63
9 Farm Buildings/Structures 2 94264.49 2959035.12
10 Farm Buildings/Structures 2 94142.48 2959383.94
11 Farm Buildings/Structures 2 91870.21 2958890.47
12 Cement Dam 5 96117.00 2959414.63
13 Farm Buildings/Structures 2 94334.97 2959701.03
14 Cement Dam 5 93882.75 2959278.60
15 Houses (Informal) 1 92404.13 2959376.44
16 Houses (Informal) 1 90823.41 2961410.12
17 Farm Buildings/Structures 2 90671.57 2961421.45
18 Houses (Informal) 1 93406.77 2960166.05
19 Farm Buildings/Structures 2 93177.11 2960339.38
20 Ruins 1 92562.49 2963994.63
21 Ruins 1 92115.57 2964471.72
22 Farm Buildings/Structures 2 92360.33 2964960.35
23 Pan 6 92265.75 2964873.60
24 Building/Structure 2 93691.09 2963904.04
25 Farm Buildings/Structures 2 93650.58 2965474.73
26 Dam 5 93437.61 2965629.53
27 Building/Structure 2 94515.69 2965358.77
28 Buildings/Structures 2 94452.16 2965781.73
29 Farm Buildings/Structures 2 94401.94 2965889.92
30 Farm Buildings/Structures 2 94614.87 2965819.86
31 Buildings/Structures 2 94182.89 2965831.19
32 Farm Buildings/Structures 2 94506.25 2965951.98
33 Buildings/Structures 2 94888.31 2965575.60
34 Buildings/Structures 2 95241.47 2965558.52
35 Buildings/Structures 2 95163.84 2965457.81
36 Buildings/Structures 2 95281.46 2965301.34
37 Buildings/Structures 2 95534.71 2965379.71
38 Buildings/Structures 2 95706.88 2965861.80
39 Buildings/Structures 2 96163.88 2965395.46
40 Buildings/Structures 2 96648.36 2965563.84
41 Buildings/Structures 2 94468.67 2964640.27
42 Reservoir 5 94518.78 2964682.23
43 Buildings/Structures 2 94438.80 2964502.00
44 Farm Buildings/Structures 2 94470.70 2963028.96
45 Buildings/Structures 2 93920.24 2961542.49
46 Buildings/Structures (inside Mining Area) 2 94173.73 2961470.71
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47 Graveyard (inside Mining Area) 7 94702.56 2961903.67
48 Buildings/Structures 2 96020.90 2962775.77
49 Buildings/Structures 2 96426.55 2963644.04
50 Vaal River 6 96603.05 2963556.31
51 Pivot Irrigation 5 97538.38 2963747.54
52 Pivot Irrigation 5 97855.68 2963392.88
53 Pivot Irrigation 5 98155.96 2963068.31
54 Pivot Irrigation 5 98619.65 2963118.05
55 Rand Water Board Canal 5 95533.62 2962488.07
56 Rand Water Board Canal Bridge 5 95476.97 2962565.63
57 Rand Water Board Canal Bridge 5 95330.07 2962749.22
58 Rand Water Board Canal Bridge 5 95184.62 2962911.07
59 Rand Water Board Canal 5 94991.42 2963130.12
60 Rand Water Board Canal Bridge 5 94956.16 2963308.28
61 Rand Water Board Canal Bridge 5 94740.41 2963785.82
62 Rand Water Board Canal Bridge 5 95690.39 2962195.65
63 Rand Water Board Canal 5 95750.21 2961900.50
64 Rand Water Board Canal Bridge 5 95701.90 2961516.59
65 Rand Water Board Canal Bridge 5 95541.02 2961208.40
66 Rand Water Board Canal 5 95431.93 2960885.39
67 Rand Water Board Canal Bridge 5 95456.46 2960701.78
68 Road 5 95550.92 2962621.30
69 Road 5 95773.37 2962241.64
70 Road 5 95306.16 2962929.52
71 Graveyard (inside Mining Area) 7 94944.93 2962291.63
During the site visit the structures were observed and the initial POI list ground‐truthed and
finalised as represented in this section. Structures ranged from well‐built structures to informal
building styles. Table 6 shows photos of structures found in the area.
Table 6: Structure Profile
Structure Photo Description
Grave Yard
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Grave Yard
Grave Yard
Grave Yard
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Solar installation
Powerlines
Kraal
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Old infrastructure
Rand Water Board
Canal
Rand Water Board
Canal
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Rand Water Board
Canal
Farm entrance
Farm house
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Rand Water Board
Canal
Rand Water Board
Canal
Farmstead
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Piggery
Rand Water Board
Canal
Rand Water Board
Canal
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Rand Water Board
Canal
Farm structure
Farmstead
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15 Construction Phase: Impact Assessment and Mitigation Measures
The Prime Spot Trading 11 (Pty) Ltd. Project area is evaluated in detail in the following sections.
The planned quarry is currently non‐operational. Setting up and site preparation of the quarry is
considered for this report as part of the construction phase. No drilling and blasting is expected to
be done.
16 Operational Phase: Impact Assessment and Mitigation Measures
The Prime Spot Trading 11 (Pty) Ltd. Project area is evaluated in detail in the following sections as
part of the operational phase. This phase impact assessment evaluates the expected levels of
ground vibration, air blast and fly rock. The levels and distances are calculated for each influence.
The predicted levels are plotted as amplitude contour maps, evaluated in relation to identified POI
and discussed. Where exceedance of levels is expected mitigation measures are recommended
and the impact assessment is done considering the pre‐ and post‐mitigation measures. As part of
the process recommendations are made that should be considered by the end user.
In all cases ground vibration and air blast was calculated from the edge of the quarry outline and
modelled accordingly. A worst case is then applicable with calculation from quarry edge.
16.1 Review of expected ground vibration
Presented herewith are the expected ground vibration level contours and discussion of relevant
influences. Expected ground vibration levels were calculated for each POI identified surrounding
the mining area and evaluated with regards to possible structural concerns and human perception.
Tables are provided for each of the different charge models done with regards to:
“Tag” No. is the number corresponding to the POI figures.
“Description” indicates the type of the structure.
“Distance” is the distance between the structure and edge of the quarry area.
“Specific Limit” is the maximum limit for ground vibration at the specific structure or
installation.
“Predicted PPV (mm/s)” is the calculated ground vibration at the structure.
The “Structure Response @ 10Hz and Human Tolerance @ 30Hz” indicates the possible
concern and if there is any concern for structural damage or potential negative human
perception respectively. Indicators used are “perceptible”,” unpleasant”, “intolerable”
which stems from the human perception information given and indicators such as “high” or
“low” is given for the possibility of damage to a structure. Levels below 0.76 mm/s could be
considered to have low or negligible possibility of influence.
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Ground vibration is calculated and modelled for the quarry area at the minimum and maximum
charge mass at specific distances from the quarry area. The charge masses applied are according
to blast designs discussed in Section 14. These levels are then plotted and overlaid with current
mining plans to observe possible influences at structures identified. Structures or POI’s for
consideration are also plotted in this model. Ground vibration predictions were done considering
distances ranging from 50 m to 1500 m around the quarry mining area.
The simulation provided shows ground vibration contours only for a limited number of levels. The
levels used are considered the basic limits that will applicable for the type of structures observed
surrounding the quarry area. These levels are: 6 mm/s, 12.5 mm/s, 25 mm/s and 50 mm/s. This
enables immediate review of possible concerns that may be applicable to any of the privately
owned structures, social gathering areas or sensitive installations.
Data is provided as follows: Vibration contours; a table with predicted ground vibration values and
evaluation for each POI. Additional colour codes used in the tables are as follows:
Structure Evaluations:
Vibration levels higher than proposed limit applicable to Structures / Installations is coloured “Red”
People’s Perception Evaluation:
Vibration levels indicated as Intolerable on human perception scale is coloured “Red”
Vibration levels indicated as Complaint on human perception scale is coloured “Mustard”
Vibration levels indicated as Perceptible on human perception scale is coloured “Light Green”
General:
POI’s that are found inside the project area is coloured “Olive Green”
Simulations for expected ground vibration levels from minimum and maximum charge mass are
presented below.
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Pit 2 Minimum charge mass per delay 75 kg
Figure 9: Pit 2 minimum charge ground vibration evaluation
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Table 7: Pit 2 minimum charge ground vibration evaluation
Tag Description Specific Limit
(mm/s) Distance
(m) Predicted
PPV (mm/s)
Structure Response @
10Hz
Human Tolerance @ 30Hz
1 Farm Animal Related Structures
(Kanhym Estates) 25 2445 0.1 Acceptable Too Low
2 Chicken Broilers Animal Related
Structures 25 2083 0.1 Acceptable Too Low
3 Dam 50 2915 0.1 Acceptable N/A
4 Buildings/Structures 25 3443 0.1 Acceptable Too Low
5 Farm Animal Related Structures 25 2721 0.1 Acceptable Too Low
6 Sand works 50 2970 0.1 Acceptable N/A
7 Buildings/Structures 25 3010 0.1 Acceptable Too Low
8 Dam 50 3128 0.1 Acceptable N/A
9 Farm Buildings/Structures 25 2679 0.1 Acceptable Too Low
10 Farm Buildings/Structures 25 2377 0.1 Acceptable Too Low
11 Farm Buildings/Structures 25 4049 0.0 Acceptable Too Low
12 Cement Dam 50 2541 0.1 Acceptable N/A
13 Farm Buildings/Structures 25 2017 0.1 Acceptable Too Low
14 Cement Dam 50 2567 0.1 Acceptable N/A
15 Houses (Informal) 6 3328 0.1 Acceptable Too Low
16 Houses (Informal) 6 3889 0.0 Acceptable Too Low
17 Farm Buildings/Structures 25 4039 0.0 Acceptable Too Low
18 Houses (Informal) 6 2074 0.1 Acceptable Too Low
19 Farm Buildings/Structures 25 2100 0.1 Acceptable Too Low
20 Ruins 6 3018 0.1 Acceptable Too Low
21 Ruins 6 3666 0.1 Acceptable Too Low
22 Farm Buildings/Structures 25 3808 0.0 Acceptable Too Low
23 Pan 150 3815 0.0 Acceptable N/A
24 Building/Structure 25 2132 0.1 Acceptable Too Low
25 Farm Buildings/Structures 25 3512 0.1 Acceptable Too Low
26 Dam 50 3740 0.1 Acceptable N/A
27 Building/Structure 25 3154 0.1 Acceptable Too Low
28 Buildings/Structures 25 3582 0.1 Acceptable Too Low
29 Farm Buildings/Structures 25 3697 0.1 Acceptable Too Low
30 Farm Buildings/Structures 25 3597 0.1 Acceptable Too Low
31 Buildings/Structures 25 3684 0.1 Acceptable Too Low
32 Farm Buildings/Structures 25 3742 0.1 Acceptable Too Low
33 Buildings/Structures 25 3331 0.1 Acceptable Too Low
34 Buildings/Structures 25 3317 0.1 Acceptable Too Low
35 Buildings/Structures 25 3213 0.1 Acceptable Too Low
36 Buildings/Structures 25 3064 0.1 Acceptable Too Low
37 Buildings/Structures 25 3172 0.1 Acceptable Too Low
38 Buildings/Structures 25 3676 0.1 Acceptable Too Low
39 Buildings/Structures 25 3344 0.1 Acceptable Too Low
40 Buildings/Structures 25 3675 0.1 Acceptable Too Low
41 Buildings/Structures 25 2459 0.1 Acceptable Too Low
42 Reservoir 50 2489 0.1 Acceptable N/A
43 Buildings/Structures 25 2332 0.1 Acceptable Too Low
44 Farm Buildings/Structures 25 964 0.5 Acceptable Too Low
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45 Buildings/Structures Mine owned 25 813 0.6 Acceptable Too Low
46 Buildings/Structures (inside
Mining Area) 25 611 1.0 Acceptable Perceptible
47 Graveyard (inside Mining Area) 50 57 51.0 Problematic N/A
48 Buildings/Structures 25 1035 0.4 Acceptable Too Low
49 Buildings/Structures 25 1919 0.2 Acceptable Too Low
50 Vaal River 150 1979 0.1 Acceptable N/A
51 Pivot Irrigation 150 2837 0.1 Acceptable N/A
52 Pivot Irrigation 150 2948 0.1 Acceptable N/A
53 Pivot Irrigation 150 3120 0.1 Acceptable N/A
54 Pivot Irrigation 150 3580 0.1 Acceptable N/A
55 Rand Water Board Canal 25 471 1.6 Acceptable N/A
56 Rand Water Board Canal Bridge 25 482 1.5 Acceptable N/A
57 Rand Water Board Canal Bridge 25 571 1.1 Acceptable N/A
58 Rand Water Board Canal Bridge 25 680 0.9 Acceptable N/A
59 Rand Water Board Canal 25 884 0.6 Acceptable N/A
60 Rand Water Board Canal Bridge 25 1064 0.4 Acceptable N/A
61 Rand Water Board Canal Bridge 25 1566 0.2 Acceptable N/A
62 Rand Water Board Canal Bridge 25 533 1.3 Acceptable N/A
63 Rand Water Board Canal 25 658 0.9 Acceptable N/A
64 Rand Water Board Canal Bridge 25 728 0.8 Acceptable N/A
65 Rand Water Board Canal Bridge 25 776 0.7 Acceptable N/A
66 Rand Water Board Canal 25 929 0.5 Acceptable N/A
67 Rand Water Board Canal Bridge 25 1096 0.4 Acceptable N/A
68 Road 150 573 1.1 Acceptable N/A
69 Road 150 617 1.0 Acceptable N/A
70 Road 150 733 0.8 Acceptable N/A
71 Graveyard (inside Mining Area) 50 95 21.8 Acceptable N/A
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Pit 2 Maximum charge per delay 450 kg
Figure 10: Pit 2 maximum charge ground vibration evaluation
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Table 8: Pit 2 maximum charge ground vibration evaluation
Tag Description Specific Limit
(mm/s) Distance
(m) Predicted
PPV (mm/s)
Structure Response @
10Hz
Human Tolerance @ 30Hz
1 Farm Animal Related Structures
(Kanhym Estates) 25 2445 0.5 Acceptable Too Low
2 Chicken Broilers Animal Related
Structures 25 2083 0.6 Acceptable Too Low
3 Dam 50 2915 0.3 Acceptable N/A
4 Buildings/Structures 25 3443 0.3 Acceptable Too Low
5 Farm Animal Related Structures 25 2721 0.4 Acceptable Too Low
6 Sand works 50 2970 0.3 Acceptable N/A
7 Buildings/Structures 25 3010 0.3 Acceptable Too Low
8 Dam 50 3128 0.3 Acceptable N/A
9 Farm Buildings/Structures 25 2679 0.4 Acceptable Too Low
10 Farm Buildings/Structures 25 2377 0.5 Acceptable Too Low
11 Farm Buildings/Structures 25 4049 0.2 Acceptable Too Low
12 Cement Dam 50 2541 0.4 Acceptable N/A
13 Farm Buildings/Structures 25 2017 0.6 Acceptable Too Low
14 Cement Dam 50 2567 0.4 Acceptable N/A
15 Houses (Informal) 6 3328 0.3 Acceptable Too Low
16 Houses (Informal) 6 3889 0.2 Acceptable Too Low
17 Farm Buildings/Structures 25 4039 0.2 Acceptable Too Low
18 Houses (Informal) 6 2074 0.6 Acceptable Too Low
19 Farm Buildings/Structures 25 2100 0.6 Acceptable Too Low
20 Ruins 6 3018 0.3 Acceptable Too Low
21 Ruins 6 3666 0.2 Acceptable Too Low
22 Farm Buildings/Structures 25 3808 0.2 Acceptable Too Low
23 Pan 150 3815 0.2 Acceptable N/A
24 Building/Structure 25 2132 0.6 Acceptable Too Low
25 Farm Buildings/Structures 25 3512 0.2 Acceptable Too Low
26 Dam 50 3740 0.2 Acceptable N/A
27 Building/Structure 25 3154 0.3 Acceptable Too Low
28 Buildings/Structures 25 3582 0.2 Acceptable Too Low
29 Farm Buildings/Structures 25 3697 0.2 Acceptable Too Low
30 Farm Buildings/Structures 25 3597 0.2 Acceptable Too Low
31 Buildings/Structures 25 3684 0.2 Acceptable Too Low
32 Farm Buildings/Structures 25 3742 0.2 Acceptable Too Low
33 Buildings/Structures 25 3331 0.3 Acceptable Too Low
34 Buildings/Structures 25 3317 0.3 Acceptable Too Low
35 Buildings/Structures 25 3213 0.3 Acceptable Too Low
36 Buildings/Structures 25 3064 0.3 Acceptable Too Low
37 Buildings/Structures 25 3172 0.3 Acceptable Too Low
38 Buildings/Structures 25 3676 0.2 Acceptable Too Low
39 Buildings/Structures 25 3344 0.3 Acceptable Too Low
40 Buildings/Structures 25 3675 0.2 Acceptable Too Low
41 Buildings/Structures 25 2459 0.4 Acceptable Too Low
42 Reservoir 50 2489 0.4 Acceptable N/A
43 Buildings/Structures 25 2332 0.5 Acceptable Too Low
44 Farm Buildings/Structures 25 964 2.1 Acceptable Perceptible
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45 Buildings/Structures Mine owned 25 813 2.8 Acceptable Perceptible
46 Buildings/Structures (inside
Mining Area) 25 611 4.5 Acceptable Perceptible
47 Graveyard (inside Mining Area) 50 57 223.6 Problematic N/A
48 Buildings/Structures 25 1035 1.9 Acceptable Perceptible
49 Buildings/Structures 25 1919 0.7 Acceptable Too Low
50 Vaal River 150 1979 0.6 Acceptable N/A
51 Pivot Irrigation 150 2837 0.4 Acceptable N/A
52 Pivot Irrigation 150 2948 0.3 Acceptable N/A
53 Pivot Irrigation 150 3120 0.3 Acceptable N/A
54 Pivot Irrigation 150 3580 0.2 Acceptable N/A
55 Rand Water Board Canal 25 471 6.9 Acceptable N/A
56 Rand Water Board Canal Bridge 25 482 6.6 Acceptable N/A
57 Rand Water Board Canal Bridge 25 571 5.0 Acceptable N/A
58 Rand Water Board Canal Bridge 25 680 3.7 Acceptable N/A
59 Rand Water Board Canal 25 884 2.4 Acceptable N/A
60 Rand Water Board Canal Bridge 25 1064 1.8 Acceptable N/A
61 Rand Water Board Canal Bridge 25 1566 0.9 Acceptable N/A
62 Rand Water Board Canal Bridge 25 533 5.6 Acceptable N/A
63 Rand Water Board Canal 25 658 4.0 Acceptable N/A
64 Rand Water Board Canal Bridge 25 728 3.3 Acceptable N/A
65 Rand Water Board Canal Bridge 25 776 3.0 Acceptable N/A
66 Rand Water Board Canal 25 929 2.2 Acceptable N/A
67 Rand Water Board Canal Bridge 25 1096 1.7 Acceptable N/A
68 Road 150 573 5.0 Acceptable N/A
69 Road 150 617 4.4 Acceptable N/A
70 Road 150 733 3.3 Acceptable N/A
71 Graveyard (inside Mining Area) 50 95 95.8 Problematic N/A
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Pit 3 Minimum charge per delay 75 kg
Figure 11: Pit 3 minimum charge ground vibration evaluation
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Table 9: Pit 3 minimum charge ground vibration evaluation
Tag Description Specific Limit
(mm/s) Distance
(m) Predicted
PPV (mm/s)
Structure Response @
10Hz
Human Tolerance @ 30Hz
1 Farm Animal Related Structures
(Kanhym Estates) 25 2791 0.1 Acceptable Too Low
2 Chicken Broilers Animal Related
Structures 25 2421 0.1 Acceptable Too Low
3 Dam 50 3292 0.1 Acceptable N/A
4 Buildings/Structures 25 3818 0.0 Acceptable Too Low
5 Farm Animal Related Structures 25 3054 0.1 Acceptable Too Low
6 Sand works 50 3398 0.1 Acceptable N/A
7 Buildings/Structures 25 3421 0.1 Acceptable Too Low
8 Dam 50 3560 0.1 Acceptable N/A
9 Farm Buildings/Structures 25 2688 0.1 Acceptable Too Low
10 Farm Buildings/Structures 25 2350 0.1 Acceptable Too Low
11 Farm Buildings/Structures 25 3771 0.1 Acceptable Too Low
12 Cement Dam 50 2874 0.1 Acceptable N/A
13 Farm Buildings/Structures 25 2020 0.1 Acceptable Too Low
14 Cement Dam 50 2495 0.1 Acceptable N/A
15 Houses (Informal) 6 3059 0.1 Acceptable Too Low
16 Houses (Informal) 6 3444 0.1 Acceptable Too Low
17 Farm Buildings/Structures 25 3593 0.1 Acceptable Too Low
18 Houses (Informal) 6 1842 0.2 Acceptable Too Low
19 Farm Buildings/Structures 25 1826 0.2 Acceptable Too Low
20 Ruins 6 2694 0.1 Acceptable Too Low
21 Ruins 6 3348 0.1 Acceptable Too Low
22 Farm Buildings/Structures 25 3576 0.1 Acceptable Too Low
23 Pan 150 3561 0.1 Acceptable N/A
24 Building/Structure 25 2011 0.1 Acceptable Too Low
25 Farm Buildings/Structures 25 3533 0.1 Acceptable Too Low
26 Dam 50 3734 0.1 Acceptable N/A
27 Building/Structure 25 3339 0.1 Acceptable Too Low
28 Buildings/Structures 25 3760 0.1 Acceptable Too Low
29 Farm Buildings/Structures 25 3868 0.0 Acceptable Too Low
30 Farm Buildings/Structures 25 3804 0.0 Acceptable Too Low
31 Buildings/Structures 25 3815 0.0 Acceptable Too Low
32 Farm Buildings/Structures 25 3931 0.0 Acceptable Too Low
33 Buildings/Structures 25 3587 0.1 Acceptable Too Low
34 Buildings/Structures 25 3635 0.1 Acceptable Too Low
35 Buildings/Structures 25 3519 0.1 Acceptable Too Low
36 Buildings/Structures 25 3396 0.1 Acceptable Too Low
37 Buildings/Structures 25 3544 0.1 Acceptable Too Low
38 Buildings/Structures 25 4056 0.0 Acceptable Too Low
39 Buildings/Structures 25 3806 0.0 Acceptable Too Low
40 Buildings/Structures 25 4195 0.0 Acceptable Too Low
41 Buildings/Structures 25 2619 0.1 Acceptable Too Low
42 Reservoir 50 2663 0.1 Acceptable N/A
43 Buildings/Structures 25 2480 0.1 Acceptable Too Low
44 Farm Buildings/Structures 25 1009 0.4 Acceptable Too Low
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45 Buildings/Structures Mine owned 25 427 1.8 Acceptable Perceptible
46 Buildings/Structures (inside
Mining Area) 25 330 2.8 Acceptable Perceptible
47 Graveyard (inside Mining Area) 50 138 11.9 Acceptable N/A
48 Buildings/Structures 25 1703 0.2 Acceptable Too Low
49 Buildings/Structures 25 2557 0.1 Acceptable Too Low
50 Vaal River 150 2631 0.1 Acceptable N/A
51 Pivot Irrigation 150 3505 0.1 Acceptable N/A
52 Pivot Irrigation 150 3617 0.1 Acceptable N/A
53 Pivot Irrigation 150 3779 0.1 Acceptable N/A
54 Pivot Irrigation 150 4236 0.0 Acceptable N/A
55 Rand Water Board Canal 25 1137 0.4 Acceptable N/A
56 Rand Water Board Canal Bridge 25 1134 0.4 Acceptable N/A
57 Rand Water Board Canal Bridge 25 1149 0.4 Acceptable N/A
58 Rand Water Board Canal Bridge 25 1184 0.3 Acceptable N/A
59 Rand Water Board Canal 25 1256 0.3 Acceptable N/A
60 Rand Water Board Canal Bridge 25 1401 0.3 Acceptable N/A
61 Rand Water Board Canal Bridge 25 1796 0.2 Acceptable N/A
62 Rand Water Board Canal Bridge 25 1166 0.4 Acceptable N/A
63 Rand Water Board Canal 25 1185 0.3 Acceptable N/A
64 Rand Water Board Canal Bridge 25 1197 0.3 Acceptable N/A
65 Rand Water Board Canal Bridge 25 1191 0.3 Acceptable N/A
66 Rand Water Board Canal 25 1322 0.3 Acceptable N/A
67 Rand Water Board Canal Bridge 25 1467 0.2 Acceptable N/A
68 Road 150 1226 0.3 Acceptable N/A
69 Road 150 1258 0.3 Acceptable N/A
70 Road 150 1274 0.3 Acceptable N/A
71 Graveyard (inside Mining Area) 50 552 1.2 Acceptable N/A
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Pit 3 Maximum charge per delay 450 kg
Figure 12: Pit 3 maximum charge ground vibration evaluation
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Table 10: Pit 3 maximum charge ground vibration evaluation
Tag Description Specific Limit
(mm/s) Distance
(m) Predicted PPV (mm/s)
Structure Response @
10Hz
Human Tolerance @ 30Hz
1 Farm Animal Related Structures
(Kanhym Estates) 25 2791 0.4 Acceptable Too Low
2 Chicken Broilers Animal Related
Structures 25 2421 0.5 Acceptable Too Low
3 Dam 50 3292 0.3 Acceptable N/A
4 Buildings/Structures 25 3818 0.2 Acceptable Too Low
5 Farm Animal Related Structures 25 3054 0.3 Acceptable Too Low
6 Sand works 50 3398 0.3 Acceptable N/A
7 Buildings/Structures 25 3421 0.3 Acceptable Too Low
8 Dam 50 3560 0.2 Acceptable N/A
9 Farm Buildings/Structures 25 2688 0.4 Acceptable Too Low
10 Farm Buildings/Structures 25 2350 0.5 Acceptable Too Low
11 Farm Buildings/Structures 25 3771 0.2 Acceptable Too Low
12 Cement Dam 50 2874 0.3 Acceptable N/A
13 Farm Buildings/Structures 25 2020 0.6 Acceptable Too Low
14 Cement Dam 50 2495 0.4 Acceptable N/A
15 Houses (Informal) 6 3059 0.3 Acceptable Too Low
16 Houses (Informal) 6 3444 0.3 Acceptable Too Low
17 Farm Buildings/Structures 25 3593 0.2 Acceptable Too Low
18 Houses (Informal) 6 1842 0.7 Acceptable Too Low
19 Farm Buildings/Structures 25 1826 0.7 Acceptable Too Low
20 Ruins 6 2694 0.4 Acceptable Too Low
21 Ruins 6 3348 0.3 Acceptable Too Low
22 Farm Buildings/Structures 25 3576 0.2 Acceptable Too Low
23 Pan 150 3561 0.2 Acceptable N/A
24 Building/Structure 25 2011 0.6 Acceptable Too Low
25 Farm Buildings/Structures 25 3533 0.2 Acceptable Too Low
26 Dam 50 3734 0.2 Acceptable N/A
27 Building/Structure 25 3339 0.3 Acceptable Too Low
28 Buildings/Structures 25 3760 0.2 Acceptable Too Low
29 Farm Buildings/Structures 25 3868 0.2 Acceptable Too Low
30 Farm Buildings/Structures 25 3804 0.2 Acceptable Too Low
31 Buildings/Structures 25 3815 0.2 Acceptable Too Low
32 Farm Buildings/Structures 25 3931 0.2 Acceptable Too Low
33 Buildings/Structures 25 3587 0.2 Acceptable Too Low
34 Buildings/Structures 25 3635 0.2 Acceptable Too Low
35 Buildings/Structures 25 3519 0.2 Acceptable Too Low
36 Buildings/Structures 25 3396 0.3 Acceptable Too Low
37 Buildings/Structures 25 3544 0.2 Acceptable Too Low
38 Buildings/Structures 25 4056 0.2 Acceptable Too Low
39 Buildings/Structures 25 3806 0.2 Acceptable Too Low
40 Buildings/Structures 25 4195 0.2 Acceptable Too Low
41 Buildings/Structures 25 2619 0.4 Acceptable Too Low
42 Reservoir 50 2663 0.4 Acceptable N/A
43 Buildings/Structures 25 2480 0.4 Acceptable Too Low
44 Farm Buildings/Structures 25 1009 2.0 Acceptable Perceptible
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45 Buildings/Structures Mine owned 25 427 8.1 Acceptable Unpleasant
46 Buildings/Structures (inside
Mining Area) 25 330 12.3 Acceptable Unpleasant
47 Graveyard (inside Mining Area) 50 138 52.1 Problematic N/A
48 Buildings/Structures 25 1703 0.8 Acceptable Perceptible
49 Buildings/Structures 25 2557 0.4 Acceptable Too Low
50 Vaal River 150 2631 0.4 Acceptable N/A
51 Pivot Irrigation 150 3505 0.3 Acceptable N/A
52 Pivot Irrigation 150 3617 0.2 Acceptable N/A
53 Pivot Irrigation 150 3779 0.2 Acceptable N/A
54 Pivot Irrigation 150 4236 0.2 Acceptable N/A
55 Rand Water Board Canal 25 1137 1.6 Acceptable N/A
56 Rand Water Board Canal Bridge 25 1134 1.6 Acceptable N/A
57 Rand Water Board Canal Bridge 25 1149 1.6 Acceptable N/A
58 Rand Water Board Canal Bridge 25 1184 1.5 Acceptable N/A
59 Rand Water Board Canal 25 1256 1.4 Acceptable N/A
60 Rand Water Board Canal Bridge 25 1401 1.1 Acceptable N/A
61 Rand Water Board Canal Bridge 25 1796 0.8 Acceptable N/A
62 Rand Water Board Canal Bridge 25 1166 1.5 Acceptable N/A
63 Rand Water Board Canal 25 1185 1.5 Acceptable N/A
64 Rand Water Board Canal Bridge 25 1197 1.5 Acceptable N/A
65 Rand Water Board Canal Bridge 25 1191 1.5 Acceptable N/A
66 Rand Water Board Canal 25 1322 1.2 Acceptable N/A
67 Rand Water Board Canal Bridge 25 1467 1.1 Acceptable N/A
68 Road 150 1226 1.4 Acceptable N/A
69 Road 150 1258 1.4 Acceptable N/A
70 Road 150 1274 1.3 Acceptable N/A
71 Graveyard (inside Mining Area) 50 552 5.3 Acceptable N/A
16.2 Summary of ground vibration levels
The Quarry operations were evaluated for expected levels of ground vibration from future blasting
operations. Review of the sites and the surrounding installations / houses / buildings showed that
structures vary in distances from the quarry area for Pit 2 and Pit 3. The influences will also vary
with distance from the specific area. The evaluation considered a distance up to 3500 m from the
Pit 2 and Pit 3 quarry areas. Structures identified outside of the quarry area but within the mining
area ranged from the Graveyard and Buildings/Structures and structures identified that are close
to the quarry area are the Rand Water Board Canal and the road. Structure conditions ranged
from industrial construction (Rand Water Board Canal) to poor condition old structures. The POI’s
identified and shown is a point that may represent a multiple of structures. A total of 71 POI’s
were identified within the 3500 m radius around the quarry.
The ground vibration levels predicted ranged between 0.2 mm/s and 223.6 mm/s for Pit 2 and 0.2
mm/s and 52.1 mm/s for Pit 3 structures surrounding the quarry areas. There are two graveyards
located inside the mine boundary. The one (POI47) is located 57 m from Pit 2 and 138 m from Pit 3
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and the second graveyard (POI71) is 95 m from Pit 2 and 552 m from Pit 3. Both graveyards are the
main concerns with regards to ground vibration. These were indicated in all tables. Ground
vibration levels predicted for these POI’s are greater than the recommended ground vibration
limit. Both graveyards are closest to Pit 2. Levels ranges between 52.1 and 224 mm/s on maximum
charges for both pit areas. The expected levels of ground vibration for the graveyards is high and
will require specific mitigations in the way of adjusting charge mass per delay to reduce the levels
of ground vibration.
16.3 Ground Vibration and human perception
Considering the effect of ground vibration with regards to human perception, vibration levels
calculated were applied to an average of 30Hz frequency and plotted with expected human
perceptions on the safe blasting criteria graph (see Figure 13 below). Data applicable to human
response only is plotted. The frequency range selected is the expected average range for
frequencies that will be measured for ground vibration when blasting is done. From Figure 13 it
can be seen that the ground vibration levels predicted levels are such that it could be experienced
as perceptible up to 1750 m. Unpleasant levels are only expected from distances of 611 m and
closer.
Figure 13: The effect of ground vibration with human perception and vibration limits
6 6
12.5 12.5
1750m
611m
0.1
1
10
100
1000
1 10 100
Gro
und
Vib
ratio
n (m
m/s
)
Frequency (Hz)
Prime Spot 11 Pty Ltd. ProjectGround Vibration Limits & Human Perception
Perceptible Unpleasant Intolerable
Predicted PPV (mm/s) 6mm/s Limit 12.5mm/s Limit
1750m 611m 330m
Perceptible
Unpleasant
Intolerable
Safe Blasting Zone
Above Limit ZoneVibration at 30Hz
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16.4 Vibration impact on roads
The Vischgat gravel road on the western side of the quarry boundary is located 573 m from Pit 2
and 1226 m from Pit 3 from the quarry areas. There is no concern associated for this gravel
regarding ground vibration. No specific actions are required for these roads.
16.5 Potential that vibration will upset adjacent communities
Ground vibration and air blast generally upset people living in the vicinity of mining operations.
The nearest settlement of people is approximately 611 m from the quarry area. These settlements
outside the quarry areas are located such that levels of ground vibration predicted may be
perceptible and unpleasant but not damaging.
The importance of good public relations cannot be over‐stressed. People tend to react negatively
on experiencing effects from blasting such as ground vibration and air blast. Even at low levels
when damage to structures is out of the question it may upset people. Proper and appropriate
communication with neighbours about blasting, monitoring and actions done for proper control
will be required.
16.6 Review of expected air blast
Presented herewith are the expected air blast level contours and discussion of relevant influences.
Expected air blast levels were calculated for each POI identified surrounding the mining area and
evaluated with regards to possible structural concerns. Tables are provided for each of the
different charge models done with regards to:
“Tag” No. is number corresponding to the location indicated on POI figures.
“Description” indicates the type of the structure.
“Distance” is the distance between the structure and edge of the quarry area.
“Air Blast (dB)” is the calculated air blast level at the structure.
“Possible concern” indicates if there is any concern for structural damage or human
perception. Indicators used are:
o “Problematic" where there is real concern for possible damage – at levels greater
than 134 dB.
o “Complaint” where people will be complaining due to the experienced effect on
structures at levels of 120 dB and higher (not necessarily damaging).
o “Acceptable” if levels are less than 120 dB.
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o “Low” where there is very limited possibility that the levels will give rise to any
influence on people or structures. Levels below 115 dB could be considered to have
low or negligible possibility of influence.
Presented are simulations for expected air blast levels from two different charge masses at the
quarry area. Colour codes used in tables are as follows:
Air blast levels higher than proposed limit is coloured “Red”
Air blast levels indicated as possible Complaint is coloured “Mustard”
POI’s that are found inside the project area is coloured “Olive Green”
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Pit 2 Minimum charge mass per delay 75 kg
Figure 14: Pit 2 Minimum charge Air blast evaluation
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Table 11: Pit 2 Minimum charge Air blast evaluation
Tag Description Distance (m) Air blast (dB) Possible Concern?
1 Farm Animal Related Structures (Kanhym
Estates) 2445 111.8 Acceptable
2 Chicken Broilers Animal Related Structures 2083 113.2 Acceptable
3 Dam 2915 110.4 N/A
4 Buildings/Structures 3443 108.9 Acceptable
5 Farm Animal Related Structures 2721 110.9 Acceptable
6 Sand works 2970 110.2 N/A
7 Buildings/Structures 3010 110.1 Acceptable
8 Dam 3128 109.7 N/A
9 Farm Buildings/Structures 2679 111.0 Acceptable
10 Farm Buildings/Structures 2377 112.0 Acceptable
11 Farm Buildings/Structures 4049 107.6 Acceptable
12 Cement Dam 2541 111.5 N/A
13 Farm Buildings/Structures 2017 113.4 Acceptable
14 Cement Dam 2567 111.4 N/A
15 Houses (Informal) 3328 109.2 Acceptable
16 Houses (Informal) 3889 108.0 Acceptable
17 Farm Buildings/Structures 4039 107.6 Acceptable
18 Houses (Informal) 2074 113.2 Acceptable
19 Farm Buildings/Structures 2100 113.1 Acceptable
20 Ruins 3018 110.1 Acceptable
21 Ruins 3666 108.5 Acceptable
22 Farm Buildings/Structures 3808 108.1 Acceptable
23 Pan 3815 108.1 N/A
24 Building/Structure 2132 113.0 Acceptable
25 Farm Buildings/Structures 3512 108.8 Acceptable
26 Dam 3740 108.3 N/A
27 Building/Structure 3154 109.7 Acceptable
28 Buildings/Structures 3582 108.6 Acceptable
29 Farm Buildings/Structures 3697 108.3 Acceptable
30 Farm Buildings/Structures 3597 108.6 Acceptable
31 Buildings/Structures 3684 108.5 Acceptable
32 Farm Buildings/Structures 3742 108.3 Acceptable
33 Buildings/Structures 3331 109.2 Acceptable
34 Buildings/Structures 3317 109.2 Acceptable
35 Buildings/Structures 3213 109.5 Acceptable
36 Buildings/Structures 3064 110.0 Acceptable
37 Buildings/Structures 3172 109.7 Acceptable
38 Buildings/Structures 3676 108.5 Acceptable
39 Buildings/Structures 3344 109.2 Acceptable
40 Buildings/Structures 3675 108.5 Acceptable
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Tag Description Distance (m) Air blast (dB) Possible Concern?
41 Buildings/Structures 2459 111.8 Acceptable
42 Reservoir 2489 111.7 N/A
43 Buildings/Structures 2332 112.3 Acceptable
44 Farm Buildings/Structures 964 119.6 Acceptable
45 Buildings/Structures Mine owned 813 121.1 Complaint
46 Buildings/Structures (inside Mining Area) 611 123.5 Complaint
47 Graveyard (inside Mining Area) 57 143.4 N/A
48 Buildings/Structures 1035 119.0 Acceptable
49 Buildings/Structures 1919 113.8 Acceptable
50 Vaal River 1979 113.6 N/A
51 Pivot Irrigation 2837 110.6 N/A
52 Pivot Irrigation 2948 110.2 N/A
53 Pivot Irrigation 3120 109.8 N/A
54 Pivot Irrigation 3580 108.6 N/A
55 Rand Water Board Canal 471 125.6 N/A
56 Rand Water Board Canal Bridge 482 125.5 N/A
57 Rand Water Board Canal Bridge 571 124.0 N/A
58 Rand Water Board Canal Bridge 680 122.5 N/A
59 Rand Water Board Canal 884 120.3 N/A
60 Rand Water Board Canal Bridge 1064 118.8 N/A
61 Rand Water Board Canal Bridge 1566 115.6 N/A
62 Rand Water Board Canal Bridge 533 124.6 N/A
63 Rand Water Board Canal 658 122.8 N/A
64 Rand Water Board Canal Bridge 728 122.0 N/A
65 Rand Water Board Canal Bridge 776 121.4 N/A
66 Rand Water Board Canal 929 120.0 N/A
67 Rand Water Board Canal Bridge 1096 118.5 N/A
68 Road 573 124.0 N/A
69 Road 617 123.4 N/A
70 Road 733 121.9 N/A
71 Graveyard (inside Mining Area) 95 139.1 N/A
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Pit 2 Maximum charge per delay 450 kg
Figure 15: Pit 2 Maximum charge Air blast evaluation
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Table 12: Pit 2 Maximum charge Air blast evaluation
Tag Description Distance (m) Air blast (dB) Possible Concern?
1 Farm Animal Related Structures (Kanhym
Estates) 2445 116.8 Acceptable
2 Chicken Broilers Animal Related Structures 2083 118.2 Acceptable
3 Dam 2915 115.3 N/A
4 Buildings/Structures 3443 114.0 Acceptable
5 Farm Animal Related Structures 2721 115.9 Acceptable
6 Sand works 2970 115.2 N/A
7 Buildings/Structures 3010 115.0 Acceptable
8 Dam 3128 114.7 N/A
9 Farm Buildings/Structures 2679 116.1 Acceptable
10 Farm Buildings/Structures 2377 117.1 Acceptable
11 Farm Buildings/Structures 4049 112.6 Acceptable
12 Cement Dam 2541 116.5 N/A
13 Farm Buildings/Structures 2017 118.4 Acceptable
14 Cement Dam 2567 116.4 N/A
15 Houses (Informal) 3328 114.2 Acceptable
16 Houses (Informal) 3889 113.0 Acceptable
17 Farm Buildings/Structures 4039 112.6 Acceptable
18 Houses (Informal) 2074 118.2 Acceptable
19 Farm Buildings/Structures 2100 118.1 Acceptable
20 Ruins 3018 115.0 Acceptable
21 Ruins 3666 113.4 Acceptable
22 Farm Buildings/Structures 3808 113.1 Acceptable
23 Pan 3815 113.1 N/A
24 Building/Structure 2132 118.0 Acceptable
25 Farm Buildings/Structures 3512 113.8 Acceptable
26 Dam 3740 113.3 N/A
27 Building/Structure 3154 114.6 Acceptable
28 Buildings/Structures 3582 113.6 Acceptable
29 Farm Buildings/Structures 3697 113.3 Acceptable
30 Farm Buildings/Structures 3597 113.6 Acceptable
31 Buildings/Structures 3684 113.3 Acceptable
32 Farm Buildings/Structures 3742 113.3 Acceptable
33 Buildings/Structures 3331 114.2 Acceptable
34 Buildings/Structures 3317 114.2 Acceptable
35 Buildings/Structures 3213 114.6 Acceptable
36 Buildings/Structures 3064 115.0 Acceptable
37 Buildings/Structures 3172 114.6 Acceptable
38 Buildings/Structures 3676 113.4 Acceptable
39 Buildings/Structures 3344 114.2 Acceptable
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Tag Description Distance (m) Air blast (dB) Possible Concern?
40 Buildings/Structures 3675 113.4 Acceptable
41 Buildings/Structures 2459 116.8 Acceptable
42 Reservoir 2489 116.7 N/A
43 Buildings/Structures 2332 117.2 Acceptable
44 Farm Buildings/Structures 964 124.7 Complaint
45 Buildings/Structures Mine owned 813 126.1 Complaint
46 Buildings/Structures (inside Mining Area) 611 128.5 Complaint
47 Graveyard (inside Mining Area) 57 148.5 N/A
48 Buildings/Structures 1035 124.1 Complaint
49 Buildings/Structures 1919 118.8 Acceptable
50 Vaal River 1979 118.6 N/A
51 Pivot Irrigation 2837 115.6 N/A
52 Pivot Irrigation 2948 115.3 N/A
53 Pivot Irrigation 3120 114.8 N/A
54 Pivot Irrigation 3580 113.6 N/A
55 Rand Water Board Canal 471 130.7 N/A
56 Rand Water Board Canal Bridge 482 130.5 N/A
57 Rand Water Board Canal Bridge 571 129.1 N/A
58 Rand Water Board Canal Bridge 680 127.6 N/A
59 Rand Water Board Canal 884 125.4 N/A
60 Rand Water Board Canal Bridge 1064 123.8 N/A
61 Rand Water Board Canal Bridge 1566 120.5 N/A
62 Rand Water Board Canal Bridge 533 129.6 N/A
63 Rand Water Board Canal 658 127.9 N/A
64 Rand Water Board Canal Bridge 728 127.0 N/A
65 Rand Water Board Canal Bridge 776 126.5 N/A
66 Rand Water Board Canal 929 125.0 N/A
67 Rand Water Board Canal Bridge 1096 123.6 N/A
68 Road 573 129.0 N/A
69 Road 617 128.4 N/A
70 Road 733 126.9 N/A
71 Graveyard (inside Mining Area) 95 144.1 N/A
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Pit 3 Minimum charge mass per delay 75 kg
Figure 16: Pit 3 Minimum charge Air blast evaluation
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Table 13: Pit 3 Minimum charge Air blast evaluation
Tag Description Distance (m) Air blast (dB) Possible Concern?
1 Farm Animal Related Structures (Kanhym
Estates) 2791 110.8 Acceptable
2 Chicken Broilers Animal Related Structures 2421 111.9 Acceptable
3 Dam 3292 109.4 N/A
4 Buildings/Structures 3818 108.1 Acceptable
5 Farm Animal Related Structures 3054 110.0 Acceptable
6 Sand works 3398 109.1 N/A
7 Buildings/Structures 3421 108.9 Acceptable
8 Dam 3560 108.6 N/A
9 Farm Buildings/Structures 2688 111.0 Acceptable
10 Farm Buildings/Structures 2350 112.1 Acceptable
11 Farm Buildings/Structures 3771 108.1 Acceptable
12 Cement Dam 2874 110.5 N/A
13 Farm Buildings/Structures 2020 113.4 Acceptable
14 Cement Dam 2495 111.6 N/A
15 Houses (Informal) 3059 110.0 Acceptable
16 Houses (Informal) 3444 108.9 Acceptable
17 Farm Buildings/Structures 3593 108.6 Acceptable
18 Houses (Informal) 1842 114.2 Acceptable
19 Farm Buildings/Structures 1826 114.2 Acceptable
20 Ruins 2694 111.0 Acceptable
21 Ruins 3348 109.2 Acceptable
22 Farm Buildings/Structures 3576 108.6 Acceptable
23 Pan 3561 108.6 N/A
24 Building/Structure 2011 113.4 Acceptable
25 Farm Buildings/Structures 3533 108.8 Acceptable
26 Dam 3734 108.3 N/A
27 Building/Structure 3339 109.2 Acceptable
28 Buildings/Structures 3760 108.3 Acceptable
29 Farm Buildings/Structures 3868 108.0 Acceptable
30 Farm Buildings/Structures 3804 108.1 Acceptable
31 Buildings/Structures 3815 108.1 Acceptable
32 Farm Buildings/Structures 3931 107.8 Acceptable
33 Buildings/Structures 3587 108.6 Acceptable
34 Buildings/Structures 3635 108.5 Acceptable
35 Buildings/Structures 3519 108.8 Acceptable
36 Buildings/Structures 3396 109.1 Acceptable
37 Buildings/Structures 3544 108.8 Acceptable
38 Buildings/Structures 4056 107.6 Acceptable
39 Buildings/Structures 3806 108.1 Acceptable
40 Buildings/Structures 4195 107.2 Acceptable
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Tag Description Distance (m) Air blast (dB) Possible Concern?
41 Buildings/Structures 2619 111.2 Acceptable
42 Reservoir 2663 111.1 N/A
43 Buildings/Structures 2480 111.7 Acceptable
44 Farm Buildings/Structures 1009 119.2 Acceptable
45 Buildings/Structures Mine owned 427 126.5 Complaint
46 Buildings/Structures (inside Mining Area)
Mine owned 330 128.6 Complaint
47 Graveyard (inside Mining Area) 138 136.0 N/A
48 Buildings/Structures 1703 114.8 Acceptable
49 Buildings/Structures 2557 111.5 Acceptable
50 Vaal River 2631 111.2 N/A
51 Pivot Irrigation 3505 108.8 N/A
52 Pivot Irrigation 3617 108.5 N/A
53 Pivot Irrigation 3779 108.1 N/A
54 Pivot Irrigation 4236 107.2 N/A
55 Rand Water Board Canal 1137 118.2 N/A
56 Rand Water Board Canal Bridge 1134 118.3 N/A
57 Rand Water Board Canal Bridge 1149 118.2 N/A
58 Rand Water Board Canal Bridge 1184 117.9 N/A
59 Rand Water Board Canal 1256 117.4 N/A
60 Rand Water Board Canal Bridge 1401 116.5 N/A
61 Rand Water Board Canal Bridge 1796 114.4 N/A
62 Rand Water Board Canal Bridge 1166 118.0 N/A
63 Rand Water Board Canal 1185 117.9 N/A
64 Rand Water Board Canal Bridge 1197 117.8 N/A
65 Rand Water Board Canal Bridge 1191 117.8 N/A
66 Rand Water Board Canal 1322 117.0 N/A
67 Rand Water Board Canal Bridge 1467 116.1 N/A
68 Road 1226 117.6 N/A
69 Road 1258 117.4 N/A
70 Road 1274 117.3 N/A
71 Graveyard (inside Mining Area) 552 124.3 N/A
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Pit 3 Maximum charge per delay 450 kg
Figure 17: Pit 3 Maximum charge Air blast evaluation
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Table 14: Pit 3 Maximum charge Air blast evaluation
Tag Description Distance (m) Air blast (dB) Possible Concern?
1 Farm Animal Related Structures (Kanhym
Estates) 2791 115.7 Acceptable
2 Chicken Broilers Animal Related Structures 2421 116.9 Acceptable
3 Dam 3292 114.3 N/A
4 Buildings/Structures 3818 113.1 Acceptable
5 Farm Animal Related Structures 3054 115.0 Acceptable
6 Sand works 3398 114.1 N/A
7 Buildings/Structures 3421 114.0 Acceptable
8 Dam 3560 113.7 N/A
9 Farm Buildings/Structures 2688 116.1 Acceptable
10 Farm Buildings/Structures 2350 117.1 Acceptable
11 Farm Buildings/Structures 3771 113.2 Acceptable
12 Cement Dam 2874 115.5 N/A
13 Farm Buildings/Structures 2020 118.4 Acceptable
14 Cement Dam 2495 116.7 N/A
15 Houses (Informal) 3059 115.0 Acceptable
16 Houses (Informal) 3444 114.0 Acceptable
17 Farm Buildings/Structures 3593 113.6 Acceptable
18 Houses (Informal) 1842 119.2 Acceptable
19 Farm Buildings/Structures 1826 119.3 Acceptable
20 Ruins 2694 116.0 Acceptable
21 Ruins 3348 114.2 Acceptable
22 Farm Buildings/Structures 3576 113.6 Acceptable
23 Pan 3561 113.6 N/A
24 Building/Structure 2011 118.5 Acceptable
25 Farm Buildings/Structures 3533 113.7 Acceptable
26 Dam 3734 113.3 N/A
27 Building/Structure 3339 114.2 Acceptable
28 Buildings/Structures 3760 113.3 Acceptable
29 Farm Buildings/Structures 3868 113.0 Acceptable
30 Farm Buildings/Structures 3804 113.2 Acceptable
31 Buildings/Structures 3815 113.1 Acceptable
32 Farm Buildings/Structures 3931 112.9 Acceptable
33 Buildings/Structures 3587 113.6 Acceptable
34 Buildings/Structures 3635 113.5 Acceptable
35 Buildings/Structures 3519 113.8 Acceptable
36 Buildings/Structures 3396 114.1 Acceptable
37 Buildings/Structures 3544 113.7 Acceptable
38 Buildings/Structures 4056 112.6 Acceptable
39 Buildings/Structures 3806 113.1 Acceptable
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Tag Description Distance (m) Air blast (dB) Possible Concern?
40 Buildings/Structures 4195 112.3 Acceptable
41 Buildings/Structures 2619 116.3 Acceptable
42 Reservoir 2663 116.1 N/A
43 Buildings/Structures 2480 116.7 Acceptable
44 Farm Buildings/Structures 1009 124.3 Complaint
45 Buildings/Structures ‐ Mine owned 427 131.5 Complaint
46 Buildings/Structures (inside Mining Area)
Mine Owned 330 133.7 Problematic
47 Graveyard (inside Mining Area) 138 141.0 N/A
48 Buildings/Structures 1703 119.9 Acceptable
49 Buildings/Structures 2557 116.5 Acceptable
50 Vaal River 2631 116.2 N/A
51 Pivot Irrigation 3505 113.8 N/A
52 Pivot Irrigation 3617 113.5 N/A
53 Pivot Irrigation 3779 113.2 N/A
54 Pivot Irrigation 4236 112.3 N/A
55 Rand Water Board Canal 1137 123.3 N/A
56 Rand Water Board Canal Bridge 1134 123.3 N/A
57 Rand Water Board Canal Bridge 1149 123.2 N/A
58 Rand Water Board Canal Bridge 1184 122.9 N/A
59 Rand Water Board Canal 1256 122.4 N/A
60 Rand Water Board Canal Bridge 1401 121.5 N/A
61 Rand Water Board Canal Bridge 1796 119.4 N/A
62 Rand Water Board Canal Bridge 1166 123.0 N/A
63 Rand Water Board Canal 1185 122.9 N/A
64 Rand Water Board Canal Bridge 1197 122.8 N/A
65 Rand Water Board Canal Bridge 1191 122.9 N/A
66 Rand Water Board Canal 1322 122.0 N/A
67 Rand Water Board Canal Bridge 1467 121.1 N/A
68 Road 1226 122.6 N/A
69 Road 1258 122.4 N/A
70 Road 1274 122.3 N/A
71 Graveyard (inside Mining Area) 552 129.3 N/A
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16.7 Summary of findings for air blast
The review of the air blast levels indicates the less influence than ground vibration. Most of the
structures identified around the pit areas are not influenced by air blast. Air blast levels predicted
does not indicate possible damage but levels are such that it could lead to complaints. Air blast
predicted for the maximum charge ranges between 124 and 129 dB for Pit 2 and 3. This includes
structures that are within the mining areas and mined owned structures. Four POI’s were
identified for Pit 2 and 2 POI’s for Pit 3 where people are present that where levels are less than
limits but could give rise to complaints. The maximum expected for these are 131.5 dB. One POI ‐
Buildings/Structures at POI 46 for Pit 3 is of concern with levels just greater than general accepted
limit of 134 dB. The levels predicted are lower than the levels expected to induce damages such as
broken windows.
Complaints from air blast are normally based on the actual effects that are experienced due to
rattling of roof, windows, doors etc. These effects could startle people and raise concern of
possible damage. The current accepted limit on air blast is 134 dB. Damages are only expected to
occur at levels greater than 134dB. On prediction it is expected that air blast will be greater than
134 dB at a distance of 300 m and closer to the quarry boundaries.
Stemming control will be required to manage the effects of air blast.
16.8 Fly‐rock unsafe zone
The occurrence of fly rock in any form will have a negative impact if found to travel outside the
unsafe zone. This unsafe zone may be anything between 10m or 1000m. A general unsafe zone is
normally considered to be within a radius of 500 m from the blast; but needs to be qualified and
determined as best possible.
Calculations are used to help and assist determining safe distances. A safe distance from blasting is
calculated following rules and guidelines from the International Society of Explosives Engineers
(ISEE) Blasters Handbook. Using this calculation the minimum safe distances can be determined
that should be cleared of people, animals and equipment. Figure 18 shows the results from the
ISEE calculations for fly rock range based on an 89 mm diameter blast hole and 2.0 m stemming
length. Based on these values a possible fly rock range with a safety factor of 2 was calculated to
be 237 m. The absolute minimum unsafe zone is then the 237 m. This calculation is a guideline and
any distance cleared should not be less. The occurrence of fly rock can however never be 100%
excluded. Best practices should be implemented at all times. The occurrence of fly rock can be
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mitigated but the possibility of the occurrence thereof can never be eliminated. Figure 19 shows
the area around the quarry that incorporates the 237 m unsafe zone.
Figure 18: Fly rock prediction calculation
237
0
100
200
300
400
500
600
700
800
1 1.5 2 2.5 3 3.5 4
Th
row
Dis
tan
ce (
m)
Burden / Stemming Length (m)
Prime Spot 11 Pty Ltd. Project ‐ Overburden Blast Fly RockMaximum Throw Distance vs Burden/Stemming Height
Actual Stemming Fly Rock Calc - ISEE Fly Rock Calc - ISEE
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Figure 19: Predicted Fly Rock Exclusion Zone for Pit 2 & Pit 3
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Review of the calculated unsafe zone showed two POI’s within the unsafe zone. This includes
mainly the two Graveyards that falls within the Mining Area. Table 15 below shows the POI’s of
concern and coordinates.
Table 15: Fly rock concern POI’s
Tag Description Y X Distance (m)
Pit 2
47 Graveyard (inside Mining Area) 94702.56 2961903.67 57
71 Graveyard (inside Mining Area) 94944.93 2962291.63 95
Pit 3
47 Graveyard (inside Mining Area) 94702.56 2961903.67 138
16.9 Noxious fumes
The occurrence of fumes in the form the NOx gas is not a given and very dependent on various
factors as discussed in Section 13.6. However the occurrence of fumes should be closely
monitored. Furthermore, nothing can be stated as to fume dispersal to nearby houses, but if
anybody is present in the path of the fume cloud it could be problematic.
16.10 Potential Environmental Impact Assessment: Operational Phase
The following is the impact assessment of the various concerns covered by this report. The matrix
below in Table 16 was used for analysis and evaluation of aspects discussed in this report. The
outcome of the analysis is provided in Table 17 before mitigation and in Table 18 after mitigation.
This risk assessment is a one sided analysis and needs to be discussed with role players in order to
obtain a proper outcome and mitigation.
Table 16: Evaluation matrix criteria
Aspect Description Weight Description
Probability: This describes the likelihood of the impact actually occurring.
Probability None 0 None
Improbable 1 The possibility of the impact occurring is very low, due to the circumstances, design or experience.
Probable 2 There is a probability that the impact will occur to the extent that provision must be made therefore.
Medium Probable
3 There is a probability that the impact could happen infrequently requiring provision to be made.
Highly Probable
4 It is most likely that the impact will occur at some stage of the development.
Definite 5 The impact will take place regardless of any prevention plans, and there
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can only be relied on mitigatory actions or contingency plans to contain the effect.
Duration: The lifetime of the impact
Duration Immediate 1 The impact will either disappear with mitigation or will be mitigated through natural processes in a time span shorter than any of the phases.
Short term 2 Short‐term (0‐7 years) (impact ceases after the operational life of the activity)
Medium term 3 The impact will last up to the end of the phases, where after it will be negated.
Long term 4 The impact will last for the entire operational phase of the project but will be mitigated by direct human action or by natural processes thereafter.
Permanent 5 Impact that will be non‐transitory. Mitigation either by man or natural processes will not occur in such a way or in such a time span that the impact can be considered transient.
Scale: The physical and spatial size of the impact
Scale International 5 International
National 4 National
Regional 3 Regional
Local 2 Local
Site Only 1 Site only
Magnitude/ Severity: Does the impact destroy the environment, or alter its function.
Magnitude Very High 10 Very high/don’t know
High 8 High
Moderate 6 Moderate
Low 4 Low
Minor 2 Minor
Significance: This is an indication of the importance of the impact in terms of both physical extent and time scale, and therefore indicates the level of mitigation required.
Positive + The impact is non‐existent or unsubstantial and is of no or little importance to any stakeholder and can be ignored.
Low <30 The impact is limited in extent, has low to medium intensity; whatever its probability of occurrence is, the impact will not have a material effect on the decision and is likely to require management intervention with increased costs.
Moderate 30 ‐ 75 The impact is of importance to one or more stakeholders, and its intensity will be medium or high; therefore, the impact may materially affect the decision, and management intervention will be required.
High >75 The impact could render development options controversial or the project unacceptable if it cannot be reduced to acceptable levels; and/or the cost of management intervention will be a significant factor in mitigation.
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Table 17: Risk assessment outcome before mitigation
No. Impact Significance Spatial Scale Temporal Scale Probability Significance Before
Mitigation
Score Magnitude Score Magnitude Score Magnitude Score Magnitude Score Magnitude
Operational Phase
1 Ground vibration Impact on houses 2 Low 3 Local 4 Long‐Term 2 Unlikely 1.20 Low
2 Ground vibration Impact on graveyards 5 Very High 3 Local 4 Long‐Term 5 Going to Happen 4.00 High
2 Ground vibration Impact on canal 5 Very High 3 Local 4 Long‐Term 3 Could Happen 2.40 Moderate
3 Ground vibration Impact on roads 1 Very Low 3 Local 4 Long‐Term 1 Impossible 0.53 Very Low
4 Air blast Impact on houses 2 Low 3 Local 4 Long‐Term 4 Very Likely 2.40 Moderate
6 Air blast Impact on roads 0 No Impact 3 Local 4 Long‐Term 1 Impossible 0.47 Very Low
4 Air blast Impact on graveyards 0 No Impact 3 Local 4 Long‐Term 1 Impossible 0.47 Very Low
6 Air blast Impact on canal 0 No Impact 3 Local 4 Long‐Term 1 Impossible 0.47 Very Low
7 Fly Rock Impact on houses 2 Low 3 Local 4 Long‐Term 2 Unlikely 1.20 Low
8 Fly Rock Impact on graveyards 5 Very High 3 Local 4 Long‐Term 5 Going to Happen 4.00 High
9 Fly Rock Impact on canal 3 Moderate 3 Local 4 Long‐Term 3 Could Happen 2.00 Low
9 Fly Rock Impact on roads 1 Very Low 3 Local 4 Long‐Term 2 Unlikely 1.07 Low
10 Impact of Fumes ‐ Houses 3 Moderate 3 Local 4 Long‐Term 3 Could Happen 2.00 Low
Closure and Post‐Closure Phase
0 0 0 0 0.00 Very Low
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Table 18: Risk assessment outcome after mitigation
No. Impact Mitigation Measures Significance Spatial Scale Temporal Scale Probability Significance after
Mitigation
Score Magnitude Score Magnitude Score Magnitude Score Magnitude Score Magnitude
Operational Phase Operational Phase
1 Ground vibration Impact
on houses 2 Low 3 Local 4 Long‐Term 2 Unlikely 1.20 Low
2 Ground vibration Impact
on graveyards
Reduce Charge Mass/Delay over
decreasing distance towards POI's of
concern. Monitoring
3 Moderate 3 Local 4 Long‐Term 3 Could Happen 2.00 Low
2 Ground vibration Impact
on canal
Reduce Charge Mass/Delay over
decreasing distance towards POI's of
concern. Monitoring
2 Low 3 Local 4 Long‐Term 2 Unlikely 1.20 Low
3 Ground vibration Impact
on roads 1 Very Low 3 Local 4 Long‐Term 1 Impossible 0.53 Very Low
4 Air blast Impact on
houses 2 Low 3 Local 4 Long‐Term 3 Could Happen 1.80 Low
6 Air blast Impact on
roads 0 No Impact 3 Local 4 Long‐Term 1 Impossible 0.47 Very Low
4 Air blast Impact on
graveyards 0 No Impact 3 Local 4 Long‐Term 1 Impossible 0.47 Very Low
6 Air blast Impact on canal 0 No Impact 3 Local 4 Long‐Term 1 Impossible 0.47 Very Low
7 Fly Rock Impact on
houses 2 Low 3 Local 4 Long‐Term 2 Unlikely 1.20 Low
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8 Fly Rock Impact on
graveyards
Increase stemming length, controls put in
place for management of stemming lengths.
3 Moderate 3 Local 4 Long‐Term 3 Could Happen 2.00 Low
9 Fly Rock Impact on canal
Increase stemming length, controls put in
place for management of stemming lengths.
2 Low 3 Local 4 Long‐Term 2 Unlikely 1.20 Low
9 Fly Rock Impact on
roads 1 Very Low 3 Local 4 Long‐Term 2 Unlikely 1.07 Low
10 Impact of Fumes –
Houses 3 Moderate 3 Local 4 Long‐Term 3 Could Happen 2.00 Low
Closure and Post‐Closure Phase
Closure and Post‐Closure Phase
0 0 0 0 0.00 Very Low
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16.11 Mitigations
The main point of concern for this operation is the graveyard located inside the mining area. In
review of the evaluations made in this report it is certain that specific mitigation will be required.
There are specific ground vibration concerns on installations close to the quarry area. There are
concerns for the two Graveyards inside the Mining Area.
Air blast and fly rock can be controlled using proper charging methodology irrespective of the
blasthole diameter and patterns used. The only way to mitigate air blast is the design of the
stemming length and stemming material. This will require changed blast design to ensure energy
levels remain as expected but with increased stemming lengths and the use of proper stemming
material. The used of a crushed product with size of 10 % of the blasthole diameter is the
recommended material.
Specific impacts are expected at the following POI’s identified. Table 19 shows list of POI’s that will
need to be considered as defined above. Figure 20 shows the location of these POI’s in relation to
the quarry area.
Table 19: Structures at the Quarry Area identified as problematic
Tag Description Y X Specific Limit
(mm/s) Distance
(m) Predicted
PPV (mm/s)
Structure Response @ 10Hz
Pit 2
47 Graveyard (inside
Mining Area) 94702.56 2961903.67 50 57 223.6 Problematic
71 Graveyard (inside
Mining Area) 94944.93 2962291.63 50 95 95.8 Problematic
Pit 3
47 Graveyard (inside
Mining Area) 94702.56 2961903.67 50 138 52.1 Problematic
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Figure 20: Structures identified where ground vibration mitigation will be required.
Mitigation of ground vibration for this can be done applying the following methods:
Do blast design that considers the actual blasting and the ground vibration levels to be
adhered too,
Change the initiating system to facilitate less blast holes detonating simultaneously making
using of electronic initiation that allow for single hole firing. Single blasthole firing will
facilitate less ground vibration but are still structures close enough to be influenced. See
section 16.1.
Do design for smaller diameter blast holes that will use fewer explosives per blasthole.
Table 20 shows mitigation in the form of maximum charge mass allowed and minimum distance
require for the maximum charge used in the evaluation. Firstly the maximum charge mass per
delay that will satisfy the required limits for the actual distance between blast area and point of
concern is shown. Secondly the minimum distance required to satisfy limits for the maximum
charge used in evaluation.
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Table 20: Mitigation measures for ground vibration
Tag Description Y X Specific Limit
(mm/s) Distance (m)
Total Mass/Delay
(kg)
Predicted PPV (mm/s)
Structure Response @
10Hz
Maximum Charge allowed
Pit 2
47 Graveyard (inside
Mining Area) 94702.56 2961903.67 50 57 73 50.0 Acceptable
71 Graveyard (inside
Mining Area) 94944.93 2962291.63 50 95 205 50.0 Acceptable
Pit 3
47 Graveyard (inside
Mining Area) 94702.56 2961903.67 50 138 428 50.0 Acceptable
Minimum distance allowed for maximum charge
Pit 2
47 Graveyard (inside
Mining Area) 94702.56 2961903.67 50 141 450 50.0 Acceptable
The information provided above clearly indicates that additional measure will be required. The
graveyards are located such that Pit 2 blasting operation at closest point to the graveyards will
required single blasthole firing for graveyard at POI 47 and multiple charges per delay can be
allowed for graveyard at POI 71 but with mass less than 205 kg. Single blasthole firing will be
easier to manage in this case. The minimum distance for maximum charge between a blast and
any of the graveyards to maintain ground vibration levels within limits are 141 m. Longer
stemming lengths will also be required for control of fly rock. This will help reduce the charge mass
per blasthole and manage expected levels of ground vibrations. Blasting areas further away or on
the opposite benches will assist with mitigation of the ground vibrations. Specific designs with
distance between blast and the graveyard will certainly be required to ensure ground vibration is
managed. Further the National Heritage Resources Act (No 25 of 1999) must be consulted regarding the
graveyard and its location. It is also recommended that the grave yard must be fenced off. The
National Heritage Resources Act may have other additional restrictions that is outside the scope of
this report.
17 Closure Phase: Impact Assessment and Mitigation Measures
During the closure phase no mining, drilling and blasting operations are expected.
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18 Alternatives (Comparison and Recommendation)
No specific alternative mining methods are currently under discussion or considered for drilling
and blasting. The only alternative is obtaining material from existing quarries. There are no
existing quarries in the vicinity and nearest is too far to make this project cost effective.
19 Monitoring
A monitoring programme for recording blasting operations is recommended. The following
elements should be part of such a monitoring program:
Ground vibration and air blast results
Blast Information summary
Meteorological information at time of the blast
Video Recording of the blast
Fly rock observations
Most of the above aspects do not require specific locations of monitoring. Ground vibration and
air blast monitoring requires identified locations for monitoring. Monitoring of ground vibration
and air blast is done to ensure that the generated levels of ground vibration and air blast comply
with recommendations. Proposed positions were selected to indicate the nearest points of
interest at which levels of ground vibration and air blast should be within the accepted norms and
standards as proposed in this report. The monitoring of ground vibration will also qualify the
expected ground vibration and air blast levels and assist in mitigating these aspects properly. This
will also contribute to proper relationships with the neighbours. Six monitoring positions were
identified around the mining area. The canal must be monitored at nearest point from a blast. This
may vary on actual point monitored that those indicated for the Rand Water Board canal.
Monitoring positions are indicated in Figure 21 and Table 21 lists the positions with coordinates.
These points will need to be re‐defined with the initial first blast and consider the final blast design
that will be applicable.
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Figure 21: Monitoring Positions suggested for the Quarry.
Table 21: List of possible monitoring positions
Tag Description Y X
44 Farm Buildings/Structures 94470.70 2963028.96
47 Graveyard (inside Mining Area) 94702.56 2961903.67
48 Buildings/Structures 96020.90 2962775.77
55 Rand Water Board Canal 95533.62 2962488.07
62 Rand Water Board Canal Bridge 95690.39 2962195.65
71 Graveyard (inside Mining Area) 94944.93 2962291.63
20 Recommendations
The following recommendations are proposed.
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20.1 Regulatory requirements
Regulatory requirements indicate specific requirements for all non‐mining structures and
installations within 500 m from the mining operation. There are mainly four installations identified
that falls within this regulation. The two Graveyards and Rand Water Board Canal are observed
within the 500 m. The quarry will have to apply for the necessary authorisations as pre‐scribed in
the various acts. Table 22 shows list of these installations. Figure 22 below shows the 500 m
boundary around the quarry area. The location of non‐mining installations is clearly observed.
Table 22: List of possible installations within regulatory 500 m
Tag Description Y X
47 Graveyard (inside Mining Area) 94702.56 2961903.67
55 Rand Water Board Canal 95533.62 2962488.07
56 Rand Water Board Canal Bridge 95476.97 2962565.63
71 Graveyard (inside Mining Area) 94944.93 2962291.63
Figure 22: Regulatory 500 m range for the Quarry
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20.2 Graveyard
Additional to the normal Mine Health and Safety Act regulations the National Heritage Resources Act
(No 25 of 1999) must be consulted regarding the graveyard and its location. The two graveyards are in
the middle of the operations and may be problematic regarding ground vibration and damages
due to fly rock. It is also recommended that these graveyards must be fenced off.
20.3 Blast Designs
The blast designs used in this report forms part of the initial consideration of blasting operations.
In this evaluation there is scope to review the final blast designs to be used. It is then highly
recommended that this blast design be reviewed and a detail blasting code of practice be
prepared and accepted for the development of the quarry. Designing of blasts must consider the
location of the blast and location of surface structures. The expected levels of ground vibration
and air blast must be considered and calculated for the nearest surface structures. The design
must consider final pattern, charging configurations and timing taken into account.
The following should be considered in the design:
Blast Initiation should rather be electronic initiation
Blasthole diameters can be reconsidered to be 76 mm diameter
Stemming lengths must be at least 30 times the current blasthole diameter thus – 89mm x
30 mm = 2.7 m
Stemming material must be crushed aggregate: 10 % of blasthole diameter= ‐ +7‐12 mm
20.4 Safe blasting distance and evacuation
Calculated minimum safe distance is 237 m. This is the estimated area that must be cleared at east
around a blast before firing. General evacuation used in the mining industry is at least 500 m from
any blast. This may be further in some cases. The final blast designs that may be used will
determine the final decision on safe distance to evacuate people and animals. This distance may
be greater pending the final code of practice of the mine and responsible blaster’s decision on safe
distance. The blaster has a legal obligation concerning the safe distance and he needs to
determine this distance.
20.5 Road Closure
The nearest road is Vischgat gravel road is closest to the operations. There are various smaller
farms roads also in the area. The Vischgat road is 573 m from the nearest point of Pit 2 and further
from Pit 3. No specific road closure of the Vischgat prescribed at this stage. Client may well decide
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to close for additional safety during blasting operations. The smaller farm roads in vicinity of the
quarry must be closed during blasting operations.
20.6 Recommended ground vibration and air blast levels
The ground vibration and air blast levels limits recommended for blasting operations in this area
are provided in Table 23.
Table 23: Recommended ground vibration air blast limits
Structure Description Ground Vibration Limit (mm/s) Air Blast Limit (dBL)
Rand Water Board Canal Infrastructure 25 N/A
National Roads/Tar Roads: 150 N/A
Electrical Lines: 75 N/A
Railway: 150 N/A
Transformers 25 N/A
Water Wells 50 N/A
Telecoms Tower 50 134
General Houses of proper construction USBM Criteria or 25 mm/sShall not exceed 134dB at point
of concern but 120 dB preferredHouses of lesser proper construction 12.5
Rural building – Traditional Build houses 6
20.7 Blasting times
A further consideration of blasting times is when weather conditions could influence the effects
yielded by blasting operations. It is recommended not to blast too early in the morning when it is
still cool or when there is a possibility of atmospheric inversion or too late in the afternoon in
winter. Do not blast in fog. Do not blast in the dark. Refrain from blasting when wind is blowing
strongly in the direction of an outside receptor. Do not blast with low overcast clouds. These ‘do
nots’ stem from the influence that weather has on air blast. The energy of air blast cannot be
increased but it is distributed differently and therefore is difficult to mitigate.
It is recommended that a standard blasting time is fixed and blasting notice boards setup at
various routes around the project area that will inform the community of blasting dates and times.
20.8 Photographic Inspections
The option of photographic survey of all structures up to 1500 m from the quarry area is
recommended. The quarry will be operating for a significant number of years. This will give
advantage on any negotiations with regards to complaints from neighbours on structural issues
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due to blasting. This process can however only succeed if done in conjunction with a proper
monitoring program. The Water Board Canal forms most of the POI’s identified. A form of
inspection is recommended due to the sensitivity of the canal operations. It is expected that
ground vibration levels will be significantly less than proposed limits at 1500 m but this process
will ensure record of the pre‐blasting status of the nearest structures to the pit areas. At 1500 m
the expected level of ground vibration will be perceptible. Figure 23 shows extent of the range of
1500 m around the quarry with POI’s identified and Table 24 shows list of the identified POI’s. It
must be noted that a point may represent a group of structures found in the vicinity of the point
identified.
Figure 23: Photographic inspection area and POI’s
Table 24: Recommended POI’s for photographic inspections
Tag Description Y X
44 Farm Buildings/Structures 94470.70 2963028.96
47 Graveyard (inside Mining Area) 94702.56 2961903.67
48 Buildings/Structures 96020.90 2962775.77
55 Rand Water Board Canal 95533.62 2962488.07
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56 Rand Water Board Canal Bridge 95476.97 2962565.63
57 Rand Water Board Canal Bridge 95330.07 2962749.22
58 Rand Water Board Canal Bridge 95184.62 2962911.07
59 Rand Water Board Canal 94991.42 2963130.12
62 Rand Water Board Canal Bridge 95690.39 2962195.65
63 Rand Water Board Canal 95750.21 2961900.50
64 Rand Water Board Canal Bridge 95701.90 2961516.59
65 Rand Water Board Canal Bridge 95541.02 2961208.40
66 Rand Water Board Canal 95431.93 2960885.39
71 Graveyard (inside Mining Area) 94944.93 2962291.63
20.9 Third party monitoring
Third party consultation and monitoring should be considered for all ground vibration and air blast
monitoring work. This will bring about unbiased evaluation of levels and influence from an
independent group. Monitoring could be done using permanent installed stations. Audit functions
may also be conducted to assist the mine in maintaining a high level of performance with regards
to blast results and the effects related to blasting operations.
21 Knowledge Gaps
The data provided from client and information gathered was sufficient to conduct this study.
Surface surroundings change continuously and this should be taken into account prior to initial
blasting operations considered. This report may need to be reviewed and update if necessary. This
report is based on data provided and internationally accepted methods and methodology used for
calculations and predictions.
22 Conclusion
Blast Management & Consulting (BM&C) was contracted as part of the Environmental Impact
Assessment (EIA) to perform an initial review of possible impacts with regards to blasting
operations in the proposed Prime Spot Trading 11 (Pty) Ltd. Project located approximately 25km
south‐east of the town of Vereeniging in the Gauteng Province, South Africa at coordinates
(Lat/Lon WGS84) 26°45'56.85"S 28° 2'51.13"E. Ground vibration, air blast, fly rock and fumes are
some of the aspects resulting from blasting operations. The report concentrates on the possible
influences of ground vibration, air blast and fly rock. It intends to provide information,
calculations, predictions, possible influences and mitigation of blasting operations for this project.
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The project area has limited installations where people congregate or being present in the vicinity.
The nearest installations are two graveyards inside the quarry boundary and the Rand Water
Board canal towards the western side of the quarry area.
The graveyards are of greatest concern for this project. One graveyard is located between Pit 2
and Pit 3 and the second south east of Pit 2. The levels of ground vibration from normal blasting
ate both graveyards are greater than allowed limits. Mitigation on blasting will be required for
both graveyards regarding ground vibration. Pit 2 is closest to both and will required reduced
charge mass per delay to mitigate ground vibration. Pit 3 is located further away and less
mitigation will be required. Mitigation measures were provided that can be followed.
The Rand Water Servitude which includes a canal and pipelines was also considered a sensitive
installation. The ground vibration levels predicted for the Rand Water Servitude were well within
the limits proposed and not expected to be in danger of induced damage due to ground vibration.
Considering fly rock there are no other structures or installations that should be considered other
than the grave yard. Stemming will be needed to ensure that fly rock is limited as best possible.
There are also regulations that will need to be followed for permission to conduct blasting
operations with these installations within 500 m from the blast operations.
Air blast predicted for the maximum charge ranges were well within accepted norms for private
installations surrounding the quarry area. No specific concerns were noted due to air blast levels
predicted.
An exclusion zone for safe blasting was also calculated. The exclusion zone was established to be
at least 237 m. Normal practice observed in mines is a 500 m exclusion zone.
Recommendations were made that should be considered, specifically for review of blast designs,
monitoring of ground vibration and air blast, safe blasting zones, safe ground vibration and air
blast limits, relocation of households, structure inspections and blasting times.
This concludes this investigation for the Prime Spot Trading 11 (Pty) Ltd. Project. There is no
reason to believe that this operation cannot continue if attention is given to the recommendations
made.
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23 Curriculum Vitae of Author
J D Zeeman was a member of the Permanent Force ‐ SA Ammunition Core for period January 1983
to January 1990. During this period, work involved testing at SANDF Ammunition Depots and
Proofing ranges. Work entailed munitions maintenance, proofing and lot acceptance of
ammunition.
From July 1992 to December 1995, Mr Zeeman worked at AECI Explosives Ltd. Initial work
involved testing science on small scale laboratory work and large scale field work. Later, work
entailed managing various testing facilities and testing projects. Due to restructuring of the
Technical Department, Mr Zeeman was retrenched but fortunately was able to take up an
appointment with AECI Explosives Ltd.’s Pumpable Emulsion Explosives Group for underground
applications.
From December 1995 to June 1997 Mr Zeeman provided technical support to the Underground
Bulk Systems Technology business unit and performed project management on new products.
Mr Zeeman started Blast Management & Consulting in June 1997. The main areas of focus are
Pre‐blast monitoring, Insitu monitoring, Post‐blast monitoring and specialized projects.
Mr Zeeman holds the following qualifications:
1985 ‐ 1987 Diploma: Explosives Technology, Technikon Pretoria
1990 ‐ 1992 BA Degree, University Of Pretoria
1994 National Higher Diploma: Explosives Technology, Technikon Pretoria
1997 Project Management Certificate: Damelin College
2000 Advanced Certificate in Blasting, Technikon SA
Member: International Society of Explosives Engineers
Blast Management & Consulting has been active in the mining industry since 1997, with work
being done at various levels for all the major mining companies in South Africa. Some of the
projects in which BM&C has been involved include:
Iso‐Seismic Surveys for Kriel Colliery in conjunction with Bauer & Crosby Pty Ltd.; Iso‐Seismic
surveys for Impala Platinum Limited; Iso‐Seismic surveys for Kromdraai Opencast Mine;
Photographic Surveys for Kriel Colliery; Photographic Surveys for Goedehoop Colliery;
Photographic Surveys for Aquarius Kroondal Platinum – Klipfontein Village; Photographic Surveys
for Aquarius – Everest South Project; Photographic Surveys for Kromdraai Opencast Mine;
Photographic inspections for various other companies, including Landau Colliery, Platinum Joint
Venture – three mini‐pit areas; Continuous ground vibration and air blast monitoring for various
coal mines; Full auditing and control with consultation on blast preparation, blasting and resultant
effects for clients, e.g. Anglo Platinum Ltd, Kroondal Platinum Mine, Lonmin Platinum, Blast
Monitoring Platinum Joint Venture – New Rustenburg N4 road; Monitoring of ground vibration
induced on surface in underground mining environment; Monitoring and management of blasting
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in close relation to water pipelines in opencast mining environment; Specialized testing of
explosives characteristics; Supply and service of seismographs and VOD measurement equipment
and accessories; Assistance in protection of ancient mining works for Rhino Minerals (Pty) Ltd.;
Planning, design, auditing and monitoring of blasting in new quarry on new road project,
Sterkspruit, with Africon, B&E International and Group 5 Roads; Structure Inspections and
Reporting for Lonmin Platinum Mine Limpopo Pandora Joint Venture 180 houses – whole village;
Structure Inspections and Reporting for Lonmin Platinum Mine Limpopo Section ‐ 1000 houses /
structures.
BM&C have installed a world class calibration facility for seismographs, which is accredited by
Instantel, Ontario Canada as an accredited Instantel facility. The projects listed above are only
part of the capability and professional work that is done by BM&C.
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24 References
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of Blasting Effects on Ground Water Supplies in Appalachia., Prepared for United
States Department of Interior Bureau of Mines.
2. BME Training Module – Vibration, air blast and fly rock, Module V, Dated 5 August
2001.
3. Chiapetta F., Van Vreden A., 2000. Vibration/Air blast Controls, Damage Criteria,
Record Keeping and Dealing with Complaints. 9th Annual BME Conference on
Explosives, Drilling and Blasting Technology, CSIR Conference Centre, Pretoria, 2000.
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07458.
5. Farnfield Dr R., Client Report: Air Overpressure from Le Maitre Flash Report, Dated: 27
April 2007.
6. Hawkins J., 9 May 2000, Impacts of Blasting on Domestic Water Wells, Workshop on
Mountaintop Mining Effects on Groundwater.
7. ISEE Blasters Handbook, 18th Edition, Little, January 2011, Ohio USA
8. Mechanical vibration and shock – Vibration of buildings – Guidelines for the
measurement and evaluation of their effects on buildings, SABS ISO 4886:1990.
9. Oriard, L.L., 1999, The Effects of Vibration and Environmental Forces: A guide for
Investigation of Structures, International Society of Explosives Engineers, Cleveland,
Ohio, USA.
10. Persson P.A., Holmberg R. and Lee J., 1994, Rock Blasting and Explosives Engineering,
Boca Raton, Florida: CRC Press.
11. Richards A. B., Moore A.J., Terrock Consulting Engineers Pty Ltd., 2002, Fly rock Control
– By Chance or Design, Paper Presented at ISEE Conference – New Orleans.
12. Rowland, J.H.(III), Mainiero R., and Hurd D.A.(Jr.), Factors Affecting Fumes Production
of an Emulsion and Anfo/Emulsion Blends.
13. Sapko M., Rowland J., Mainiero R., Zlochower I., Chemical and Physical Factors that
Influence no Production during Blasting – Exploratory Study.
14. Scott A., Open Pit Blast Design, 1996, Julius Kruttschnitt Mineral Research Centre, The
University of Queensland.
15. Siskind D.E., Stachura V.J., Stagg M.S. and Kopp J.W., 1980. Structure Response and
Damage Produced by Air blast From Surface Mining. US Bureau of Mines RI 8485.