IR-T12 Decision report template (short-form) · 2020. 3. 25. · Licence: L8893/2015/1 Decision report template (short-form) v 0.7 (November 2019) i Application to amend licence Part

Licence: L8893/2015/1

Decision report template (short-form) v 0.7 (November 2019) i

Application to amend licence

Part V Division 3 of the Environmental Protection Act 1986

Licence number L8893/2015/1

Applicant Salt Lake Mining Pty Ltd

ACN 162 824 473

DWER File Number DER2015/001006-1

Premises Beta Hunt Mine Site

St Ives Road

KAMBALDA WA 6442

Part of Mining Tenements: M15/1512, M15/1513, M15/1516, M15/1517, M15/1518, M15/1526, M15/1527, M15/1529, M15/1531, M15/1628, M15/1629, M15/1691, M15/1694, M15/1698, M15/1699, M15/1702 and M15/1705

As defined by the coordinates in Schedule 1 of the licence

Date of Report 25 March 2020

Status of Report Final

Decision Report

L8893/2015/1

IR-T06 Licence template (v5.0) (September 2019)

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1. Definitions

Key terms relevant to this decision report and their associated definitions are listed in Table 1.

Table 1: Definitions

Term Definition

ACN Australian Company Number

ASTM D1238 Standard Test Method for Melt Flow Rates of Thermoplastics by Extrusion Plastometer

ASTM D1505 Standard Test Method for Density of Plastics by the Density-Gradient Technique

ASTM D1603 Standard Test Method for Carbon Black Content in Olefin Plastics

ASTM D638 Standard Test Method for Tensile Properties of Plastics

applicant Salt Lake Mining Pty Ltd

BOM Bureau of Meteorology

Category / categories

categories of prescribed premises as set out in Schedule 1 of the EP Regulations.

CNKO Consolidated Nickel Kambalda Operations Pty Ltd

m3 cubic metres

decision report refers to this document.

Delegated Officer an officer delegated under section 20 of the EP Act.

department the department established under section 35 of the Public Sector Management Act 1994 and designated as responsible for the administration of Part V Division 3 of the EP Act.

DMIRS Department of Mines, Industry Regulation and Safety

DWER

Department of Water and Environmental Regulation

As of 1 July 2017, the Department of Environment Regulation (DER), the Office of the Environmental Protection Authority (OEPA) and the Department of Water (DoW) amalgamated to form the Department of Water and Environmental Regulation (DWER). DWER was established under section 35 of the Public Sector Management Act 1994 and is responsible for the administration of the Environmental Protection Act 1986 along with other legislation.

emission has the same meaning given to that term under the EP Act.

EP Act Environmental Protection Act 1986 (WA)

EP Regulations Environmental Protection Regulations 1987 (WA)

existing licence the licence issued under Part V, Division 3 of the EP Act and in force prior to the commencement of, and during this review.

> greater than

ha hectare

HDPE High Density Polyethylene

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Term Definition

IBC Intermediate Bulk Containers

kL kilolitres

km kilometres

kN/ m2 Kilonewton Per Square Meter

m metres

m2 Square metre

mg/L milligrams per litre

MSI Act Mines Safety and Inspection Act 1994

ML/yr megalitre per year

mm/yr millimetres per year

No. typographic abbreviation of the word number(s).

prescribed activity as defined in Schedule 1 of the Environmental Protection Regulations 1987.

prescribed premises this has the same meaning given to that term under the EP Act.

premises refers to the premises to which this decision report applies, as specified at the front of this decision report.

risk event as described in Guidance Statement: Risk Assessment.

SLM Salt Lake Mining Pty Ltd

significant rainfall event

a significant rainfall event is defined based on the Bureau of Meteorology website for the location of Kambalda (http://www.bom.gov.au/water/designRainfalls/revised-ifd/?multipoint). A significant rainfall event has been based on Intensity Frequency Duration (IFD), being 24 hours rainfall duration at 20% Annual Exceedance Probability (AEP). Note that a 20% AEP is equivalent to a 4.48 Annual Recurrence Internal (ARI).

SIGM St Ives Gold Mining Company Pty Ltd

tpa tonnes per annum

TDS Total Dissolved Solids

UDR Environmental Protection (Unauthorised Discharges) Regulations 2004 (WA)

waste has the same meaning given to that term under the EP Act.

http://www.bom.gov.au/water/designRainfalls/revised-ifd/?multipoint

http://www.bom.gov.au/water/designRainfalls/revised-ifd/?multipoint

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2. Purpose and scope of assessment

Summary of licence amendment application

Salt Lake Mining Pty Ltd (applicant) submitted an application on 1 July 2019 to the Department of Water and Environmental Regulation (DWER) for a licence amendment under the Environmental Protection Act 1986 (EP Act).

The applicant’s licence amendment application was initiated following the findings from a DWER inspection of the premises on 9 April 2019. The initial application was for the inclusion of:

• Category 64 (installation of putrescible waste landfill including burying of tyres);

• Expansion of the turkey’s nest; and

• Alterations to licensed Category 6 (mine dewatering) - installation of dewater pipeline to vent shaft for water sprays.

On 24 October 2019, the applicant provided the below updates to the initial application in response to DWER’s first request for further information.

Expansion of the turkey’s nest

• The applicant advised that works to expand the turkey’s nest will not proceed at this point in time. Therefore this item has not be included in DWER’s assessment of the licence amendment application.

Alterations to licensed Category 6 (mine dewatering) – installation of pipeline to ventilation shaft for water sprays

• The Delegated Officer notes that the applicant’s updated proposal included adding treated wastewater (treatment via a series of five settling cells) generated through the ‘Light Vehicle and Heavy Equipment’ washbay to the underground ventilation shaft; where the wastewater would migrate through a series of underground settling ponds before being returned to the surface and discharged into the lined (rock and geofabric material) turkey’s nest, which discharges to Lake Lefroy.

Upon review of the further information supplied by the applicant, the Delegated Officer considered that the washbay wastewater management proposal posed unnecessary environmental risks, specifically the potential for discharges of hydrocarbons to surface waters.

As a result of the Delegated Officer’s decision, the applicant was advised to provide DWER with an alternative proposal for the management of treated wastewater that does not pose unnecessary environmental risks to surface waters.

Alterations to wastewater management – ‘Heavy Vehicle Workshop’ washbay

• The Delegated Officer notes that the applicant’s updated proposal included managing the wastewater generated through the ‘Heavy Vehicle Workshop’ washbay by treatment through a sediment settling sump and oil water separator prior to on-site disposal via the effluent leach drain.

Supporting documentation supplied by the applicant on 24 October 2019 demonstrated that the applicant was proposing to discharge both septage wastes and wastewater generated through heavy vehicle washing activities into a single leach drain.

The Delegated Officer considered that septage waste and treated wastewater generated through heavy vehicle washing activities will likely need to be discharged to separate leach drains in order for the systems to work effectively.

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On 24 December 2019, the applicant provided the below final updates to the proposal in response to DWER’s second request for further information.

Alterations to licensed Category 06 (mine dewatering) – installation of pipeline to ventilation shaft for water sprays

• The applicant provided information to indicate that no changes to the existing approved Category 6 (mine dewatering) activities will be undertaken.

Alterations to wastewater management – ‘Heavy Vehicle Workshop’ and ‘Light Vehicle and Heavy Equipment’ washbays

• The Delegated Officer notes that the applicant’s updated proposal includes managing the wastewater generated from the ‘Heavy Vehicle Workshop’ and ‘Light Vehicle and Heavy Equipment’ washbays through a combination of wastewater recycling and discharge to a High Density Polyethylene (HDPE) lined evaporation pond.

DWER assessment

Review of existing licence conditions

The existing licence conditions for Category 6 (mine dewatering) have been reviewed and updated accordingly as part of this DWER assessment. Redundant or unenforceable conditions have been removed from the licence and where condition requirements were unclear; the text has been updated to provide the licence holder with further clarity on their obligations.

Appendix 2 provides an overview of key alterations to the existing licence.

The Delegated Officer recommends that any future applications, reviews or renewals of the licence should consider a comprehensive review of the mine dewater monitoring requirements.

Prescribed activity

This decision report assesses emissions and discharges associated with the following prescribed activity:

• Category 64 - installation and operation of two Class II putrescible waste landfills (including the burying of tyres).

Non-prescribed activity

Although the management of washbay wastewater is not considered a prescribed activity under Schedule 1 of the Environmental Protection Regulations 1987 (EP Regulations) by the Delegated Officer at the time of this assessment; there is risk that discharges to the environment may occur and therefore this decision report assesses the emissions and discharges associated with the below non-prescribed activity:

• Management of wastewater generated from the ‘Heavy Vehicle Workshop’ and ‘Light Vehicle and Heavy Equipment’ washbays through a combination of wastewater recycling and discharge to a HDPE lined evaporation pond.

No regulatory controls have been specified for this activity within the licence. The Delegated Officer notes that the general provisions of the EP Act and Environmental Protection (Unauthorised Discharges) Regulations 2004 (UDRs) are sufficient to regulate hydrocarbon, sediment, degreaser and detergent discharges at a minimum during construction and operation of the evaporation pond.

On 6 February 2020, DWER issued a letter to the applicant with the following advice for State Government Department referrals regarding the planned wastewater management activities:

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o With the proposed construction and operation of the evaporation pond, the Delegated Officer provided recommendation that the applicant notify the Department of Mines, Industry Regulation and Safety (DMIRS) of the proposal.

o Regarding the proposal to re-use treated wastewater generated through heavy and light vehicle washing activities, the Delegated Officer provided recommendation that the applicant notify the Department of Health of the proposal.

3. Overview of premises

The premises is an underground nickel sulfide and gold project located near Lake Lefroy in Kambalda. The mining tenements on which the premises is located are held by St Ives Gold Mining Company Pty Ltd (SIGM). The owner and proponent of the premises is Salt Lake Mining Pty Ltd (SLM). SLM acquired the mine in December 2013 from Consolidated Nickel Kambalda Operations Pty Ltd (CNKO). SLM operates the premises under a sub-lease agreement with SIGM.

The premises was in care and maintenance for five years and returned to operations on 24 April 2014. During that time, dewatering activities were still occurring, with mine dewater being discharged to the surface of Lake Lefroy. The same dewatering rate occurs during care and maintenance as during operations.

Licence history

Table 2 summarises the licence history for the premises.

Table 2: Licence history

Instrument Issued Nature and extent of works approval, licence or amendment

L8626/2012/1 12 April 2002 A licence was issued for the premises in April 2012 for categories 6 and 77 under Schedule 1 of the EP Regulations for the dewatering of the underground mine and the operation of a concrete batching plant.

L8626/2012/1 11 April 2013 Licence holder initiated licence amendment to remove Category 77 as the batching plant no longer existed on site.

L8626/2012/1 3 July 2014 Licence holder initiated licence amendment to increase dewatering limit. The nominated throughput for dewatering was increased from 250,000 tonnes per annum (tpa) to 380,000 tpa and later to 480,000 tpa to dewater an old section of mine to allow proposed mining of this area. Water quality from the old section of mine was considered to be similar to the existing discharge and therefore unlikely to cause additional or different environmental impact, given the management measures and licence conditions that were in place. The licence amendment included the transfer of occupier name.

L8893/2015/1 9 July 2015 The premises was previously licensed under L8626/2012/1. A new licence L8893/2015/1 was issued as a result of a late annual fee payment that resulted in L8626/2012/1 ceasing to have effect. No reassessment of emissions and discharges was undertaken for the new licence. The risk assessment of the previous licence conducted in July 2014 was transferred to the decision document of the new licence.

L8893/2015/1 25 March 2020

This licence amendment application. Inclusion of Category 64 - installation and operation of two Class II putrescible waste landfills (including the burying of tyres).

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Licence renewal

As licence L8893/2015/1 was due to expire on 8 July 2020, the Delegated Officer has decided to extend the licence expiry date by one year as part of this licence amendment application. The new expiry date for licence L8893/2015/1 is now 8 July 2021.

Classification of Premises

The application is for the inclusion of Category 64 prescribed premises as defined in Schedule 1 of the EP Regulations and listed in Table 3.

Table 3: Classification of premises and assessed throughout

Prescribed premises category description Assessed throughput

Category 64: Class II or III putrescible landfill site: premises on which waste (as determined by reference to the waste type set out in the document entitled “Landfill Waste Classification and Waste Definitions 1996” published by the Chief Executive Officer and as amended from time to time) is accepted for burial.

• 450 tonnes per annum – clean fill; inert waste type 1; uncontaminated fill; putrescible wastes; inert waste type 2 (not including tyres)

• 1,000 tonnes per annum – inert waste type 2 (tyres only)

Assessed non-prescribed activity

Management of wastewater generated from the ‘Heavy Vehicle Workshop’ and ‘Light Vehicle and Heavy Equipment’ washbays through a combination of wastewater recycling and discharge to a HDPE lined evaporation pond.

Note:

No regulatory controls have been specified for this activity within the licence as the management of washbay wastewater is not considered a prescribed activity under Schedule 1 of the EP Regulations by the Delegated Officer at the time of this assessment.

The Delegated Officer notes that the applicant controls and general provisions of the EP Act and UDRs are sufficient to regulate hydrocarbon, sediment, degreaser and detergent discharges at a minimum during wastewater management activities.

~9,500kL (9.5ML) per annum

Prescribed activity – Category 64 (two Class II putrescible landfills)

Landfill (not including tyres)

The landfill will be located west of the existing landfill along the edge of the waste dump (Figure 3). Waste will be delivered to trenches via hand or utes and service trucks. Blue rock (inert material from the waste dump) will be used as a capping material. Waste will be covered at least every 30 days or when the open area reaches >30m length x 20m width (whichever is sooner).

Waste types to be disposed of in the landfill include: plastic sample bags and containers, core trays, shorter (non-reusable polypipe lengths), broken pallets, electrical wires, conduits, machinery parts, food scraps from onsite meals (minimal input), small quantities of clean-fill and other items that are not recyclable.

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Wind-borne escapee material has not been observed as an issue to date due to the lack of light weight loose material like paper and wrappers. The waste material being deposited to the landfill is relatively heavy and unlikely to be picked-up and transported by wind. The applicant will consider fencing if wind-borne material becomes an issue.

A recycling area has been established near the landfills. Materials that are recycled include: steel, copper, wooden pallets (pallets are not chemically treated), crates, Intermediate Bulk Containers (IBC) and drums.

Hydrocarbon waste (including: oily rags, oily filters and contaminated spill absorbent material) is containerised and removed from site by a licensed controlled waste carrier.

Landfill (tyres only)

The landfill will be located in the waste dump (Figure 3). Up to 210 used tyres could be generated per year from the onsite mining fleet, the used tyres will be stockpiled in the excavation void of the designated tyre disposal area of the landfill prior to burial. Burial will occur prior to 100 used tyres being accumulated. Used tyres will be disposed of in accordance with Part 6 of the EP Regulations.

Fire management

The two Class II putrescible landfills are located on the waste dump, which is adjacent to a cleared laydown area that provides a natural firebreak. As the landfill approaches the western edge of the cleared mine area, a firebreak will be installed and maintained, as is required under the Mines Safety and Inspection Act 1994 (MSI Act). There are currently access tracks to the west of the landfill area that currently act as a fire break. The premises is equipped with fire-fighting equipment and trained personnel who form part of the mines rescue team. The Kambalda Fire Station is also located 7.4km away.

Access management

The premises is an active mine site with security measures that includes a gatehouse check-in point on the entry road. The perimeter of the waste dump and laydown area is bunded off preventing access to the area.

Stormwater management

The immediate area of the landfill is contained with the bunded top of the waste dump and the laydown area to the north is also bunded (Figure 3). Any surface runoff is anticipated to be contained in the immediate area of the waste dump and laydown area.

Leachate management

There are no significant leachate generators likely given the small size of the landfill, the predominantly inert nature of the waste and the lack of significant potential contamination sources.

The immediate area of the landfill is contained within the bunded top of the waste dump and the laydown area to the north is also bunded. Therefore, any leachate from the landfill is likely to be contained in the immediate area of the waste dump.

Odour management

The Class II waste stream is relatively small in volume and contains negligible odour emissions sources. The main potential source of odour could possibly be rotting food from meal scraps. The overall assessment is that that minimal quantities of food scraps and the location in an unpopulated area is unlikely to cause any unreasonable odour issues.

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Non-prescribed activity – washbay wastewater management

Heavy vehicle workshop wash bay

The ‘Heavy vehicle workshop wash bay’ is located immediately north of the ‘Heavy vehicle workshop’. This washbay is used for the removal of oil and grease from equipment and components. At the time of this assessment, the washbay area has been equipped with the following:

• All drainage from the ‘Heavy vehicle workshop wash and ‘Heavy vehicle workshop’ is contained by a sloping concrete apron, which directs wastewater and any spills to two sealed concrete sumps that act as sediment traps.

• Quick-break detergents are utilised at the premises and wastewater captured within the two sealed concrete sumps is then pumped through an oil water separator (Ultraspin OS35).

The oil water separator and all associated components are contained above a grated catchment sump on a stand that in turn is located over a larger grated catchment sump with any spillage directed back to the washbay sump.

Light vehicle and heavy equipment wash bay

The ‘Light vehicle and heavy equipment wash bay’ is located 50m south of the ‘Heavy vehicle workshop’. This washbay is used to wash mud and saline water from vehicles and machinery coming up from underground and is not associated with servicing or mechanical repairs. At the time of this assessment, the washbay area has been equipped with the following:

• All wastewater from the ‘Light vehicle and heavy equipment wash bay’ is contained within the washpad and then directed through a series of five sediment traps prior to collection in a holding tank.

Evaporation pond

The proposed evaporation pond will be HDPE lined and the applicant has calculated the required evaporation pond capacity based upon the Department of Agriculture (now the Department of Primary Industries and Regional Development) Evaporation basin guidelines for disposal of saline water, published in May 2006.

Wastewater recycling and disposal options

To reduce the total potable water consumption and the evaporation area required, the applicant is proposing to recycle a portion of the wastewater generated for re-use in the two washbays, with the remaining wastewater discharged to the HDPE lined evaporation pond.

Infrastructure

The premises infrastructure, as it relates to Category 64 activities, is detailed in

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Table 4 below and with reference to the site maps (as shown in Figure 1, Figure 2 and Figure 3).

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Table 4: Infrastructure and equipment

No. Infrastructure and equipment Site layout reference

(Figure 1, Figure 2 and Figure 3)

Category 64 (two Class II putrescible landfills)

1 Landfill (not including tyres) trench 80m long x 50m wide x 4m deep.

Landfill trench be extended west from the existing landfill along the edge of the waste dump.

Landfill

2 Landfill (tyres only) trench 60m long x 60m wide x 3m deep.

Tyre disposal to be located in the waste dump.

Landfill

3 Recycling area. -

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Figure 1: Map of the boundary of the prescribed premises

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Figure 2: Site layout

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Figure 3: Landfill area

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Legislative context and other approvals

The legislative framework for this assessment is the EP Act and EP Regulations.

Relevant guidance documents are outlined in Appendix 1.

Approvals relevant to the premises are outlined in the Table 5 below.

Table 5: Relevant approvals

Legislation Approval

Mining Act 1978 On 6 February 2020, DWER issued a letter providing recommendation that the applicant notify DMIRS of any updates to the existing operations.

4. Location and siting

Siting Context

The premises is located 1.6km south-east of the Kambalda town centre (Figure 6) in the Goldfields of Western Australia.

Topography

The premises is located at the south-south-east base of the elevated landform Red Hill. The premises terrain is generally a flat undulating area.

Meteorology

The Bureau of Meteorology (BOM) meteorology information was accessed on 14 January 2020 for Kalgoorlie-Boulder Airport (Site number: 012038), which is the nearest weather station to the premises and is located 60km north-north-west of the premises. The annual average rainfall at Kalgoorlie-Boulder is 266.1mm, which falls (>1mm) on an average of 39.7 rain-days. Most of the rain usually falls in February, January and June respectively.

Wind observations

BOM historical wind observations demonstrate morning (9am) winds (Figure 4) that primarily originate from the west and average between 10-20km/hr followed by wind originating from the north-west and averaging between 10-20km/hr. Afternoon (3pm) winds (Figure 5) primarily originate from the east and average between 10-20km/hr followed by wind originating from both the north-west and west directions averaging between 10-20km/hr.

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Figure 4: Kalgoorlie-Boulder Airport - 9am Rose of Wind - 22 March 1939 to 12 August 2019

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Figure 5: Kalgoorlie-Boulder Airport – 3pm Rose of Wind - 22 March 1939 to 12 August 2019

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Sensitive receptors

The distances to residential and environmental receptors are detailed in Table 6.

Figure 6 depicts the below-mentioned human and environmental receptors in proximity to the premises.

Table 6: Receptors and distance from prescribed premises boundary

Sensitive receptors Distance from prescribed premises boundary

Human receptors

People driving vehicles along St Ives Road (restricted access for mining activities)

Runs parallel to the premises and is located 885m east of the premises.

Kambalda town site Located 1.6km north-north-west of the premises.

Environmental receptors

Lake Lefroy (land locked lakebed)

Runs parallel to the premises and is located 33m south of the premises. The lakebed is isolated by the St Ives Road to the east and fringing dune shoreline to the south.

Lake Lefroy (open lakebed) Located 550m south and 930m east of the premises.

Groundwater

Due to the underground mine, the area beneath the Beta Hunt Mine in contained in a drawdown cone. The proposed landfills are elevated on the waste dump and therefore considered unlikely to have any interaction with groundwater.

The salinity of the groundwater within the premises area is typically >300,000 mg/L TDS.

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Figure 6: Regional locality map for the premises

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5. Risk assessment

The identification of the sources, pathways and receptors to determine risk events are set out in Table 7 below, consistent with the Guidance Statement: Risk Assessments. Risk ratings have been assessed for each key emission source and take into account potential source-pathway-receptor linkages.

The mitigation measures/controls proposed by the applicant have been considered in determining the risk rating.

The conditions in the issued licence, as outlined in Table 7, have been determined in accordance with the Guidance Statement: Setting Conditions.

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Risk assessment – construction and operation

Table 7: Identification of emissions, pathway, receptors and controls

Risk Events Residual Risk Continue to detailed

risk assessment

Regulatory controls and reasoning

Sources Activities Potential

emissions Potential pathway

Potential receptors

Potential adverse impacts

Applicant Controls Consequence rating*

Likelihood rating*

Risk*

Mobile equipment movements (e.g. vehicles and heavy equipment)

Construction and operation of two putrescible landfills.

Construction of the evaporation pond and installation of wastewater management pipeline(s).

Dust Via wind

People driving vehicles along St Ives Road (restricted access for mining activities).

Reduced visibility for drivers, which could potentially lead to injury or death.

For the two landfills, the small size of each progressive cell development and capping of the previous cell, possibly areas of 30m x 15m, is unlikely to create any significant dust emissions.

The blue rock material has large particle size distribution and is not prone to dust generation.

The mine site maintains dust control as required under the MSI Act.

Posted vehicle speed limits within project area.

Visual monitoring for dust during construction and maintenance activities.

Hypersaline ground waters collected from the underground workings are reticulated throughout the underground mine workings and used for dust suppression.

Severe Rare High No

St Ives Road has restricted access. The premises is an active mine site with security measures that includes a gatehouse check-in point at the entry on St Ives Road.

The mining project is located in an area where the majority of wind speeds are considered gentle, averaging less than 16km/hr (BOM, 2019).

The elevated Red Hill landform located north-north-west of the premises acts as a buffer to the Kambalda town site.

No regulatory controls specified in the licence. The Delegated Officer determines that the applicant controls are likely to be sufficient at mitigating potential dust emissions during construction and operation activities.

The Delegated Officer notes that Section 49 of the EP Act is sufficient to regulate dust emissions during construction and operation activities.

Kambalda town site located 1.6km north-north-west of the premises.

Health and amenity impacts to human receptors in Kambalda town site.

Minor Rare Low No

Native vegetation.

Dust deposition to native vegetation species can potentially lead to poor vegetation health.

Minor Rare Low No

Surface watercourses (Lake Lefroy):

• Land locked lakebed located 33m south of the premises.

• Open lakebed located 550m south and 930m east of the premises.

Impacts to surface water quality.

Moderate Rare Medium No

Noise Air/Wind dispersion


Amenity

For the two landfills, the small size of each progressive cell development and capping of the previous cell, possibly areas of 30m x 15m, is unlikely to create any significant noise emissions.

N/A N/A N/A N/A

The elevated Red Hill landform located north-north-west of the premises acts as a buffer to the Kambalda town site and is sufficient to inform the risk of noise as not foreseeable.

No regulatory controls specified in the licence. The Delegated Officer determines that the applicant controls are likely to be sufficient at mitigating potential noise

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risk assessment




Potential receptors



Likelihood rating*

Risk*

The machinery used will consist of modern excavators, bulldozers and trucks with engine noise control systems to meet relevant Australian Standards.

All machinery is maintained in good condition, as is required under the MSI Act.

The site works are likely to be short duration, possibly a few hours or less for each landfill campaign.

emissions during construction and operation activities.

The Delegated Officer notes that the provisions of the Environmental Protection (Noise) Regulations 1997 are sufficient to regulate noise emissions during construction and operation activities.

Operational areas

Stormwater migrating through operational areas.

Sediment (e.g. sand) and hydrocarbons (e.g. diesel).

Overland runoff

Ecosystems located downstream of operational areas.

Soil, groundwater and/or surface water contamination.

Mine infrastructure is bunded where there are risks from hydrocarbons and other workshop fluids.

There is a dedicated ‘Heavy vehicle workshop’ where servicing and maintenance activities are carried out.

The immediate area of the landfill is contained with the bunded top of the waste dump. The laydown area to the north of the landfill area is also bunded off. Any surface runoff is trapped on site.

Minor Possible Medium No

Regulatory Controls

• Condition 2 of the licence requires the licence holder to ensure that:

o clean surface water is diverted around operational areas;

o potentially contaminated and contaminated waters are retained onsite via bunds or surface diversions; and

o potentially contaminated and contaminated waters are either added to the wastewater recycling system or stored appropriately until collection and disposal at a facility approved to accept the waste.

The Delegated Officer notes that the general provisions of the EP Act and UDRs are sufficient to regulate sediment and hydrocarbon discharges during construction and operation.

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risk assessment




Potential receptors



Likelihood rating*

Risk*

Landfill operation

Acceptance of putrescible waste for burial.

Odour from the degradation of putrescible waste (rotting food from meal scraps).

Air/Wind dispersion.


Loss of amenity and nuisance impacts.

The Class II waste stream is relatively small with low quantities of food scraps.

The perimeter of the waste dump and laydown area is bunded off preventing access to the area.

Blue rock (inert material from the waste dump) will be used as a capping material and waste will be covered when an open area reaches >30m long x 20m wide or monthly, whichever is sooner.

Minor Rare Low No


There are no significant leachate generators likely given the small size of the landfill, the predominantly inert nature of the waste and the lack of significant potential contamination sources.

Due to the underground mine, the area beneath the Beta Hunt Mine in contained in a drawdown cone. The proposed landfills are elevated on the waste dump and therefore considered unlikely to have any interaction with groundwater.

Regulatory Controls

• Condition 8 of the licence stipulates the quantities and waste types allowed to be disposed of in the landfill.

• Condition 9 of the licence stipulates that waste deposited in the landfill is to be:

o covered at least every 30 days or when the open area reaches >30m length x 20m width (whichever is sooner);

o covered with a dense, inert and incombustible material; and

o totally covered, so that no waste is left exposed.

The Delegated Officer determines that the applicant and regulatory controls are likely to be sufficient at limiting access to the area and mitigating potential odour and leachate emissions from the landfill.

Uncovered waste

Access to landfill.

Ingestion affecting local fauna.

Livestock, birds and other fauna.

Increase in vermin/scavengers.


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risk assessment




Potential receptors



Likelihood rating*

Risk*

Leachate

Direct discharges to land or surface watercourses and infiltration to groundwater.

Native vegetation.

Groundwater.




Leachate has the potential to disrupt ecological processes in soil, surface waters and groundwater with excess nutrients.

The immediate area of the landfill is contained within the bunded top of the waste dump and the laydown area to the north is also bunded. Therefore, any leachate from the landfill is likely to be contained in the immediate area of the waste dump.

Hydrocarbon waste (including: oily rags, oily filters and contaminated spill absorbent material) is containerised and removed from site by a licensed controlled waste carrier.

Moderate Unlikely Medium No

Inadequate management of waste disposed in landfills

Smoke and fumes from possible fires

Air/Wind dispersion.

People driving vehicles along St Ives Road (restricted access for mining activities).

Reduced visibility for drivers, which could potentially lead to injury or death.

The two Class II putrescible landfills are located on the waste dump, which is adjacent to a cleared laydown area that provides a natural firebreak.

As the landfill approaches the western edge of the cleared mine area, a firebreak will be installed and maintained, as is required under the MSI Act. There are currently access tracks to the west of the landfill area that currently act as a fire break.

The premises is equipped with fire-fighting equipment and trained personnel who form part of the mines rescue team.

The Kambalda Fire Station is also located 7.4km away.

Severe Rare High No

Condition 9 of the licence stipulates that waste deposited in the landfill is to be:

• covered at least every 30 days or when the open area reaches >30m length x 20m width (whichever is sooner);

• covered with a dense, inert and incombustible material; and

• totally covered, so that no waste is left exposed.

The Delegated Officer determines that the applicant and regulatory controls are likely to be sufficient at mitigating potential emissions from landfill fires.

The Delegated Officer notes that the general provisions of the EP Act and UDRs are sufficient to regulate emissions from landfill fires.



Human health impacts. Moderate Unlikely Medium No

Firefighting water runoff

Direct discharges to land or surface

Native vegetation.

Exposure of native vegetation species to firefighting water

The perimeter of the waste dump and laydown area is bunded.

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risk assessment




Potential receptors



Likelihood rating*

Risk*

watercourses and infiltration to groundwater.

Groundwater.




runoff can potentially lead to poor vegetation health.

Soil, groundwater and/or surface water contamination.

Windblown waste

Acceptance of light weight loose waste material (e.g. paper and plastic packaging) for burial.

Litter Air/Wind dispersion



Wind-borne escapee material has not been observed as an issue to date due to the lack of light weight loose material like paper and wrappers.

The waste material being deposited to the landfill is relatively heavy and unlikely to be picked-up and transported by wind.

The applicant will consider fencing if wind-borne material becomes an issue.

Minor Rare Low No


Regulatory Controls

Condition 9 of the licence stipulates that waste deposited in the landfill is to be:

• covered at least every 30 days or when the open area reaches >30m length x 20m width (whichever is sooner);

• covered with a dense, inert and incombustible material; and

• totally covered, so that no waste is left exposed.

The Delegated Officer determines that the applicant and regulatory controls are likely to be sufficient at mitigating windblown waste from the landfill.


Ingestion affecting local fauna.

Severe Rare High No

Pipelines transporting washbay wastewater, series of interconnected water storage tanks and evaporation pond

Wastewater management activities.

Discharges of wastewater (hydrocarbon, sediment, degreaser and detergent) through leaks, pipeline/tank rupture or failure.

Evaporation pond bund wall failure and/or overflow of

Direct discharges to land or surface watercourses and infiltration to groundwater.

Native vegetation.

Groundwater.



• Open lakebed

An overflow of wastewater would likely damage and may cause death of native vegetation.

Hydrocarbon and nutrient loads in underlying soils, groundwater and surface watercourses.

The evaporation pond HDPE liner will be a minimum thickness of 0.75mm and will meet the specifications of ASTM D1505; (ASTM D1238 condition E 190/2.16); (ASTM D1603); (ASTM D638 type IV 2) and (ASTM D638).

To reduce the total potable water consumption and the

Major Rare Medium No

Annual average rainfall in the Kalgoorlie-Boulder area is approximately 266.1mm. The rainfall for a 1% AEP (annual exceedance probability) event over 72 hours at Kambalda is 210mm (BOM, 2019).


The Delegated Officer notes that the

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risk assessment




Potential receptors



Likelihood rating*

Risk*

wastewater during a significant rainfall event.

Seepage of wastewater through base or walls of evaporation pond.

located 550m south and 930m east of the premises.

evaporation area required, the applicant is proposing to recycle a portion of the wastewater generated for re-use in the two washbays, with the remaining wastewater discharged to the HDPE lined evaporation pond.

The ‘Heavy vehicle workshop wash bay’ wastewater is treated via sediment trap and oil water separator prior to transportation via wastewater pipelines.

The ‘Light vehicle and heavy equipment wash bay’ wastewater is treated through a series of five sediment traps prior to transportation via wastewater pipelines.

applicant controls and general provisions of the EP Act and UDRs are sufficient to regulate hydrocarbon, sediment, degreaser and detergent discharges at a minimum during wastewater management activities.

Evaporation pond

Storage of wastewater.

Not applicable Access to evaporation pond.


Entrapment and potential drowning in evaporation pond.

Ingestion of wastewater containing hydrocarbon, degreaser and detergent.

The evaporation pond will have adequate fencing to exclude livestock and fauna, with signage installed around the pond where appropriate.

The need for additional bird deterrent(s) will be assessed during operation, as the pond is situated adjacent to an active mine area with activity 24 hour per day the irregular noise from the mining activity is expected to deter birds.

Moderate Unlikely Medium No


The Delegated Officer determines that the applicant controls are likely to be sufficient at preventing access to the evaporation pond.

Mine dewater

Mine de-water will be used for onsite dust suppression.

Overspray or runoff of hypersaline water into native vegetation

Through dust suppression operations (e.g. action of spraying hypersaline water with a water cart)

Native vegetation

Death or damage of conservation significant flora by inundation of hypersaline water

The licence holder undertakes annual monitoring of vegetation located nearest to the dewatering discharge point and areas where saline water is used for dust suppression to identify whether any deterioration in the

High Unlikely Medium No

Regulatory Controls

• Condition 3 of the licence requires that saline water used for dust suppression during both construction and operation activities must be applied so as to avoid damage to vegetation (such as from overspray or runoff).

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risk assessment




Potential receptors



Likelihood rating*

Risk*

Dewatering operations at the discharge point into Lake Lefroy.

presence and/or quality of vegetation has taken place.

• Condition 7 of the licence requires the discharge of mine dewater onto Lake Lefroy via the installed energy dissipation infrastructure (rock wall located at the low point in the turkey’s nest that allows mine dewater to flow at a maximum rate of 16 L/s down the rock wall and into the lake) to minimise erosion and scouring impacts, to reduce the likelihood of ponding in Lake Lefroy and to minimise damage to fringing vegetation.

The Delegated Officer determines that the applicant and regulatory controls are likely to be sufficient at mitigating potential overspray or runoff of hypersaline water into native vegetation.

Mobile equipment (e.g. vehicles, heavy equipment, generators and pumps).

Maintenance and servicing activities.

Storage and use of hydrocarbons and chemicals.

Leaks, spills and breach of containment.

Spills to ground or leaks, overflow during filling, infiltration through soil.

Ecosystems adjacent to the area of spill or breach.

Soil, groundwater and/or surface water course contamination as well as biota impacts.

There is a dedicated ‘Heavy vehicle workshop’ where servicing and maintenance activities are carried out.

Mine infrastructure is bunded where there are risks from hydrocarbons and other workshop fluids.

All machinery is maintained in good condition, as is required under the MSI Act.


Regulatory Controls

• Schedule 2 of condition 1 of the licence requires the licence holder to undertake the following:

o Store environmentally harmful materials in secured, covered, impervious and bunded areas.

o Bunded areas to have a minimum capacity of 110% of the largest container stored within it, or 25% of the volume of all containers, whichever is the larger.

o Maintain all mobile equipment as per manufacturer’s specifications.

o Keep suitably stocked spill response equipment close to where spills may occur.

o Ensure all staff are trained to use the spill response equipment.

o Contain and clean-up spills as soon as they occur.

The Delegated Officer notes that the general provisions of the EP Act, UDRs, the Dangerous Goods Safety Act 2004 and associated regulations are sufficient to regulate hydrocarbon and chemical emissions during construction and operation.

*Consequence ratings, likelihood ratings and risk descriptions are detailed in the Department’s Guidance Statement: Risk Assessments (February 2017)

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9

Consequence and likelihood of risk events

A risk rating will be determined for risk events in accordance with the risk rating matrix set out in Table 8 below.

Table 8: Risk rating matrix

Likelihood Consequence

Slight Minor Moderate Major Severe

Almost certain Medium High High Extreme Extreme

Likely Medium Medium High High Extreme

Possible Low Medium Medium High Extreme

Unlikely Low Medium Medium Medium High

Rare Low Low Medium Medium High

DWER will undertake an assessment of the consequence and likelihood of the Risk event in accordance with Table 9 below.

Table 9: Risk criteria table

Likelihood Consequence

The following criteria has been

used to determine the likelihood of

the Risk Event occurring.

The following criteria has been used to determine the consequences of a Risk Event occurring:

Environment Public health* and amenity (such as air

and water quality, noise, and odour)

Almost

Certain

The risk event is

expected to occur

in most

circumstances

Severe • onsite impacts: catastrophic

• offsite impacts local scale: high level

or above

• offsite impacts wider scale: mid-level

or above

• Mid to long-term or permanent impact to

an area of high conservation value or

special significance^

• Specific Consequence Criteria (for

environment) are significantly exceeded

• Loss of life

• Adverse health effects: high level or

ongoing medical treatment


public health) are significantly

exceeded

• Local scale impacts: permanent loss

of amenity

Likely The risk event will

probably occur in

most circumstances

Major • onsite impacts: high level

• offsite impacts local scale: mid-level

• offsite impacts wider scale: low level

• Short-term impact to an area of high

conservation value or special

significance^


environment) are exceeded

• Adverse health effects: mid-level or

frequent medical treatment


public health) are exceeded

• Local scale impacts: high level

impact to amenity

Possible The risk event

could occur at

some time

Moderate • onsite impacts: mid-level

• offsite impacts local scale: low level

• offsite impacts wider scale: minimal


environment) are at risk of not being met

• Adverse health effects: low level or

occasional medical treatment


public health) are at risk of not being

met

• Local scale impacts: mid-level

impact to amenity

Unlikely The risk event will

probably not occur

in most

circumstances

Minor • onsite impacts: low level

• offsite impacts local scale: minimal

• offsite impacts wider scale: not

detectable


environment) likely to be met


public health) are likely to be met

• Local scale impacts: low level impact

to amenity

Rare The risk event may

only occur in

exceptional

circumstances

Slight • onsite impact: minimal


environment) met

• Local scale: minimal to amenity


public health) met

^ Determination of areas of high conservation value or special significance should be informed by the Guidance Statement: Environmental Siting. * In applying public health criteria, DWER may have regard to the Department of Health’s Health Risk Assessment (Scoping) Guidelines. “onsite” means within the Prescribed Premises boundary

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10

Acceptability and treatment of Risk event

DWER will determine the acceptability and treatment of Risk events in accordance with Risk treatment Table 16 below:

Table 10: Risk treatment table

Rating of Risk Event

Acceptability Treatment

Extreme Unacceptable. Risk event will not be tolerated. DWER may refuse application.

High May be acceptable.

Subject to multiple regulatory controls.

Risk event may be tolerated and may be subject to multiple regulatory controls. This may include both outcome-based and management conditions.

Medium Acceptable, generally subject to regulatory controls.

Risk event is tolerable and is likely to be subject to some regulatory controls. A preference for outcome-based conditions where practical and appropriate will be applied.

Low Acceptable, generally not controlled.

Risk event is acceptable and will generally not be subject to regulatory controls.

6. Consultation

Stakeholder consultation undertaken at the licence amendment assessment stage is detailed in Table 11.

Table 11: Stakeholder consultation

Method Comments received DWER response

Shire of Coolgardie advised of proposal on 15 January 2020

None received. N/A

DMIRS advised of proposal on 15 January 2020

None received. N/A

Applicant referred draft documents on 6 February 2020

The applicant did not provide comments on the draft documents.

N/A

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11

7. Conclusion

Based on this assessment, it has been determined that the application for an amendment to licence L8893/2015/1 will be granted subject to conditions commensurate with the determined controls and necessary for administration and reporting requirements.

Lauren Fox

A/MANAGER, RESOURCE INDUSTRIES

an officer delegated under section 20 of the Environmental Protection Act 1986 (WA)

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12

Appendix 1: Key documents

Document title Availability

Department of Agriculture (now the Department of Primary Industries and Regional Development) Evaporation basin guidelines for disposal of saline water, published in May 2006

Accessed at:

https://researchlibrary.agric.wa.gov.au/cgi/viewc

ontent.cgi?article=1007&context=misc_pbns

Bureau of Meteorology (BOM) meteorology

information for Kalgoorlie-Boulder Airport (Site

number: 012038)

Accessed at:

• http://www.bom.gov.au

Salt Lake Mining Pty Ltd FW: License Amendment Application, submitted 1 July 2019

DWER records (A1801750)

Salt Lake Mining Pty Ltd RE: APPLICANT NOTIFICATION - APPLICATION FOR AN AMENDMENT TO LICENCE L8893/2015/1 - REQUEST FOR FURTHER INFORMATION, submitted 19 August 2019

DWER records (DWERDT190596)

Salt Lake Mining Pty Ltd APPLICANT NOTIFICATION - APPLICATION FOR AN AMENDMENT TO LICENCE L8893/2015/1 - REQUEST FOR FURTHER INFORMATION, submitted 24 October 2019


Salt Lake Mining Pty Ltd RE: APPLICATION FOR AN AMENDMENT TO LICENCE - L8893/2015/1, submitted 24 December 2019


DER, July 2015. Guidance Statement:

Regulatory principles. Department of

Environment Regulation, Perth.

Accessed at www.dwer.wa.gov.au

DER, October 2015. Guidance Statement:

Setting conditions. Department of Environment

Regulation, Perth.

DER, November 2016. Guidance Statement: Environmental Siting. Department of Environment Regulation, Perth.

DER, February 2017 Guidance Statement: Risk

Assessments. Department of Environment

Regulation, Perth.

DWER, June 2019 Guideline: Decision Making

Department of Water and Environmental

Regulation

DWER, June 2019. Guideline: Industry Regulation Guide to Licensing

https://researchlibrary.agric.wa.gov.au/cgi/viewcontent.cgi?article=1007&context=misc_pbns

https://researchlibrary.agric.wa.gov.au/cgi/viewcontent.cgi?article=1007&context=misc_pbns

http://www.bom.gov.au/watl/evaporation/

http://www.dwer.wa.gov.au/

13

L8893/2015/1


Appendix 2: Key alterations to existing licence conditions

Existing licence condition Corresponding Licence amendment condition

Reasoning for condition update

1.1.2 (definition for ‘annual period’)

Table 7 The ‘annual period’ definition has been updated to align with the submission date of AACRs and AERs.

N/A Table 7 The following definitions have been included in the licence to provide the licence holder with further clarity on their meaning:

• energy dissipation infrastructure

• monthly period

• No.

• significant rainfall event

• tipping area

• turkey’s nest

• waste

• waste type

The following measurement abbreviations have been incorporated so that measurements can be listed in their abbreviated form throughout the licence:

• ‘kL’, ‘m’, ‘mg/L’, ‘m3/s’, and ‘tpa’

1.1.2 (definition for ‘quarterly’)

Table 4 Table 4 provides the licence holder with clarity on the required monitoring frequency.

14

L8893/2015/1




1.2.5 2 The replacement condition provides the licence holder with clearer requirements for the management of potentially contaminated and contaminated stormwater.

1.3.1 Condition has been removed from the licence. During the DWER initiated inspection of the premises carried out on 9 April 2019, it was identified that the dewatering pipelines are not equipped with automatic cut-outs and no secondary containment has been installed.

DWER notes that the dewatering pipeline is double skinned and travels from the underground workings, across the sandbar and then underground before returning to the surface at the lined (rock and geofabric material) turkey’s nest where the mine dewater is then discharged into Lake Lefroy. The aboveground section of the pipeline is approximately 200m in length and there is limited vegetation surrounding this aboveground component of the pipeline.

Risk Assessment

Consequence rating

Moderate

Likelihood rating

Unlikely

Residual risk

Medium

DWER therefore determines that the dewatering pipeline being double skinned and dewatering pipeline inspections every 12 hours to check the integrity of the pipeline when in operation are sufficient to regulate the environmental risks. As a result, the existing licence condition (1.3.1) has been removed from the licence as it is no longer applicable to how the premises manages the dewatering pipelines.

15

L8893/2015/1




3.1.1(b) 12 (Table 4) The replacement condition provides the licence holder with clearer requirements for sampling method.

1.3.2 3 and 4 The replacement condition provides the licence holder with clearer requirements for the management of mine dewater.

1.3.3(b) 18 The replacement condition requires the licence holder to compare the results of the assessment against the preceding three year period.

1.3.4 Schedule 2, No. 3. and 4 The replacement conditions provide the licence holder with clearer dewatering pipeline inspection requirements.

2.3.1 3, 4, 5, 6 and 7 The replacement conditions provide the licence holder with clearer requirements for the discharge of mine dewater.

5.1.3 17 The replacement condition provides the licence holder with clearer AACR reporting requirements and provides a specific due date of 1 March for the report.

5.2.1 18 The replacement condition provides the licence holder with clearer AER reporting requirements and provides a specific due date of 1 March for the report.

Documents

IR-T12 Decision report template (short-form) · 2020. 3. 25. · Licence: L8893/2015/1 Decision report template (short-form) v 0.7 (November 2019) i Application to amend licence Part