Correnso/SUPA Stability 2016 Annual Report · A - Modified Avoca Technique (graphic) B - Surface Drillholes Intersecting Workings ... LUC 202.2016 (SUPA) Condition 19 – Surface

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Correnso/SUPA Stability

2016 Annual Report

CORRENSO STABILITY 2016 ANNUAL REPORT


Contents

1. Purpose ........................................................................................................................ 1

2. Objectives ..................................................................................................................... 1

2.1 As required by Condition 25 of LUC 202.2012 (Correnso) ............................ 1

2.2 As required by Condition 19 of LUC 202.2016 (SUPA) .................................. 1

3. Location, Depth, Height and Volume of Stopes ......................................................... 2

4. Development & Exploration Drives ............................................................................. 3

5. Backfilling and Compaction of Stopes ....................................................................... 8

6. Ground Condition Revealed by Excavations ............................................................. 8

7. Monitoring and Measures for Stability........................................................................ 9

8. Mining Confined to Consent Boundaries ................................................................. 10

9. Review of Consent Condition Requirements ........................................................... 12

10. Conclusion ................................................................................................................. 12

11. References .................................................................................................................. 12

Appendices

A - Modified Avoca Technique (graphic) B - Surface Drillholes Intersecting Workings



1

1. PURPOSE

The purpose of the OceanaGold Waihi (OGW) Correnso/SUPA Surface Stability Annual Report is to comply with the requirements of the following Hauraki District Council (HDC) consent conditions:

LUC 202.2012 (Correnso) Condition 25 – Surface Stability

LUC 202.2016 (SUPA) Condition 19 – Surface Stability.

2. OBJECTIVES

2.1 AS REQUIRED BY CONDITION 25 OF LUC 202.2012 (CORRENSO)

25. The consent holder shall provide to the Council on an annual basis (within one month of the agreed anniversary) a report: a) Describing the location, depth height and volume (m³) of stopes; and a summary

of the data required by Condition 26 regarding unfilled stope voids; and b) Describing the lengths of development that, due to the encountered geotechnical

conditions where multiple levels overlap, will require backfilling prior to mine closure; and

c) Describing the backfilling and compaction associated with each stope; and d) Describing the ground conditions revealed by the mine excavations; and e) Describing the monitoring and measures adopted to ensure ground surface

stability, particularly as provided for in Condition 23 and the outcomes of such measures; and

f) Describing the location and depth of exploratory drives; g) Confirming that the extent of the mining works is confined to CEPPA, as defined

in Figure 1. The agreed anniversary for this report was 20 December, the date in 2013 when the first blast was initiated into the Correnso Consent Area. In agreement with HDC, this anniversary was revised to 31 December to coincide with other calendar-year data collation and reporting.

2.2 AS REQUIRED BY CONDITION 19 OF LUC 202.2016 (SUPA)

19. The consent holder shall provide to the Council an annual report (within one month of the agreed anniversary established in condition 4 or as otherwise agreed in writing by the Council): a) Describing the location, depth height and volume (m³) of stopes; and a summary

of the data required by Condition 20 regarding unfilled stope voids; and b) Describing the lengths of development that, due to the encountered geotechnical

conditions where multiple levels overlap, will require backfilling prior to mine closure; and

c) Describing the backfilling and compaction associated with each stope; and d) Describing the ground conditions revealed by the mine excavations; and e) Describing the monitoring and measures adopted to ensure ground surface

stability, particularly as provided for in Condition 15 and the outcomes of such measures; and

f) Describing the location and depth of exploratory drives; g) Confirming that the extent of the mining works is confined to SUPA, as defined in

Figure 1. These reports may be prepared in conjunction with similar reports prepared in accordance with the consent conditions applying to the Correnso Underground Mine.


2

Note: As at 31 December 2016, mine development had stayed solely within the Correnso boundary and had not crossed into SUPA.

3. LOCATION, DEPTH, HEIGHT AND VOLUME OF STOPES

(Consent conditions: Correnso c.25a, SUPA c.19a) The stoping methodology for Correnso is Modified Avoca (refer to Appendix A for a graphical representation). This method requires a ‘bottom-up’ mining technique, whereby each successively higher stope is mined out by driving on the surface of the previously laid backfill of underlying stopes. This technique also requires the development to the extremities of the ore body, then mining back towards the access points. Schematics of Correnso mining operations for the period are presented in Figures 2 and 3. Stope extraction began in mid 2015, with production continuing throughout 2016. At any one time, multiple stopes are in various states of the production cycle (drilling, blasted stocks, bogging, and backfilling). This means that some stopes may have open voids at the end of the month. By the end of the reporting period, 170,419m³ of stope volume had been extracted, with 168,988m³ backfilled (Figure 1) and mining had reached the 915 level. Stope design during the period consisted of 5m drives with up to 10m stope panels between the drives. The 10m stope height was the maximum during the year; no stopes were greater, a few were less. This results in an effective maximum void height of 20m; made up of the 10m stope and two 5m drives (one above and one below the stope). While most of the mine development is along the main vein, mining of minor offshoot ‘splay’ veins occurs when viable. These are in various states of extraction (Figure 2) and are annotated in Figure 4.

Figure 1: Cumulative monthly stope voids and backfill volumes 2016


3

4. DEVELOPMENT & EXPLORATION DRIVES

(Consent conditions: Correnso c.25b&f, SUPA c.19b&f) Figures 4 and 5 indicate development progress in Correnso as at 31 December 2016. As noted earlier, the SUPA boundary had not been crossed at year end.


4

Figure 2: Schematic Long Section of Correnso Veins

OCEANA GOLD WAIHI OPERATIONS - CORRENSO MINE SECTIONS

930L

920L 920L

910L 910L

900L

890L 890L885-1-S

880L 880L

870L 870L271

860L 860L

850L 850L

840L 840L150 40

830L 830L

820L 820LM

on

810L 810L

800L 800L Failed HW

790L 790L

780L 780L

930L

920L 920L

910L 910L

900-4-N

900L 900L

890L 890L885-5-S

111 131 168 194

880L 880L

870L 870L

C

R

860L 860L

850L 850L

840-4-HW

840L 840L69 51

830L 830L825-4-HW

`820L 820L

810L 810-4-HW 810L

800L 800L795-8-N

790L 790L

780L 780L

Legend

Open drives/unfilled stopes Backfilled drives

Backfilled areas Ore, left during mining

Un-mined stopes Pillars, not mined

Drilled, but un-mined CRF - Cement Reinforced Fill

3535

870-1-N

3510 3575 3580 3585 3590

34103245 3345

3390 3410 3415 3420 34253370 3375 3540 3545 35503470 35303525

3280

3405

3340

3440 3565

WS

3315 3320

870

ACC

and

5 - SOUTH

33303265

870-4-N

3390

34653310 3325 34603445 3450

810-4-

HW

810-4-

HW

795-4-

HW

3430 34353215

3430

3225 3235 3240

32653200

3455

915-5-S

55

810-1

N

3260 3270 341533603240

795

ACC

795-1

N

855-5-S

885-1

N885-4-N

3250 3255 3260

900-5-S

915-5-N

5 - NORTH

870-5-N

3290 3295 33853350 3370 33753355 3395

33653230 3245

3530

810-4-

HW

840

ACC

ESS

3315 3455 3460 34653415

3330

4 - NORTH

900-5-N

32953280 3285 3290

885

ACC

AND

33503335

915

ACC

885-5-N

33803355 336033453270

N

35403490 3550 35553450

3500 3505

4 - HANGING WALL

840-1

N840-5-N

3250

8 - NORTH

825-4-

HW

840-4-

HW

900

ACC

AND

900-1

N

3340

855

ACC

and

810

ACC

ESS

34853305 3395 3400

810-

FWB

T

870-1

N

3570

344533753090 3095 3100 3585 35903560 3565

33853275

3255 3260 3265 3270

825

ACC

ESS

825-1

N825-8-N

35803355 3360 3365 3370 35252995 3000 3120 3125 3130 3135

35553475 3480 3490 3495 35603515 3520

350534853240 32453225 3230 3235 34053005 3010 3015 3020 3025 3030 3035 3040 3045 3050 3055 3060 3065 3070 3075 3080 3085 32953160 3165 3170 3175 3180 31853140 3280 3285 32903105 3110 3115

S

322032153145 3150 3155

825-1

S

840-1

S

3325

810-1

S

32753190 3195 3200 3205 3210 3570 35753535347534003300 3330 3335 3340 3380 3385 3390 3395 3435 34403305 3310 35003420 3425 3430 34953320 3470 34803345 3350 3510 3515 35203410 3545

3155 3160 3165

855-1

S

3080

7 - SOUTH

31502995 3000 3005 3010 3015 3020 3025 3030 3035 3040 3045 3050 3055 3060 3065 3070 30853075 3170 31753110 3115 3120 3125 3130 3135

Break between 7 & 5

WS

3100 31053090 3145

3205

825

ACC

ESS

3085 3090 3100

3095

3095

795

ACC

325031403110 3175 3180

Break between 7 & 5

3140

885-4-

N

825-8-

N

3220

31303115

WS

3150

810-1-N

3200 32053185 3210

3280 34653425 3430 3435 3440 3445 34503395 3400 3405 3410 3415 34603420 34553290 337033553330

915-1-N

33053285 33453340 33603350 3365333033153265

825-7-

S

3185 3190

810

ACC

ESS

870

ACC

and

32503170 3175 3200 32303180

885-1-N

3240

WS

3150 3225

885

ACC

AND

900

ACC

AND

3210

855

ACC

and

33353310

840

ACC

ESS

3295

870-4-

N

1 - NORTH

900-1-N

33253275

840-1-N

3260

915

ACC

AND

32553235 32453105 3110 3140 3320

WS

3165

WS

32203215

265 287

3270

840-4-

FW

3195 32053100 3115

239

3085

900-1-S

3120

239

840-7-

S

CRF

3000 3005 30953055 3070 30752995 3010 3015 3020 3025 3030 3060 3065 30803035

3080

3040

1 - SOUTH

3155

855-7-

S

3045 316031453090

915-1-S

WS

3050 3125 3130 3135

3075304530202995 3000 3005 3010 3030

795 S

EXT

S

3060 307030653015 3025 30403035 30553050

N

3220 3285 3300 352033053160 35003225 3335 3460 34903485 3505 3515 3525 3545 3590

3.47

N/D

3555 357535653535 35403495

Pil

lar

357035603400 3530 3580 3585

3570

Deck

35403530 358535803495 3520 352535153500 355535453510 356535603550

Pilla

r

3380 3385

WS

825-4-

HW

34903390 3475 3480

Pil

lar

35753535

2.57

35903470

870-4-

HW

3450

Failed HW

Pilla

r

3505

XCXC

3435 344534403425

34853375

870-4-N870-4-HW

WS

UB

Pilla

r

855-1-NWS WS

35503510

4 - FOOTWALL

34653315

Pil

lar

3320 3455

795 S

ACC

31853120 3170

840-4-

HW

333033253145 3190 3365 3380

795-4-

HW

348034753210 34703405 342031953135 3165 32353215 3310

810-8-

N

WS

825-1-N

31953180 3190

795-8-

N

210 240 261

267

3275

289

3125 3230 32553105

810-7-

S

3155

870-5-S


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Figure 3: Schematic Long Section of Daybreak Veins

930L 930L

920L 920L

910L 910L

900L 900L

890L 890L

880L 880L

870L 870L

905

Acc905 W

890H

W890 HW

64256320 6385 6390

890

Acc

875H

W

920 W

6410 6415640063806245 639563756260 6330 6360

Daybreak East & West Hanging Wall

64206235 6240 6255

920

Acc

65706530 6535 6540 6545 6550 65556500 6505 6510 6515 6520 65656525 6560635563256290 62956230 63406205 62206210 6215 626562506195 6275 6280 6285 6365 640563156225 6270 6300 63706305 63506310 634563356145 61856155 62006160 6175 61806100 6115 6120 6125 6130 6135 6165 61706140 6150 61906105 6110 6675 669566706665 6690668566606590 66506485 6655 6680664566356595 6610 66406615 6625 6630662066056575 66006445 64656435 64906455 6470

875

Acc

6430 647564606440 6450 64956480 6580 6585

860L 860L860 HW

860

Acc

860H

W

850L 850L

845 HW845H

W

845

Acc845 HW

845H

W

845

Acc

840L 840L

830L 830L114 139

820L 820L

810L 810L

800L 800L

790L 790L

780L 780L

930L

920L 920L

910L 910L

900L 900L

890L 890L

880L 880L

870L 870L

860L 860L

850L 850L

840L 840L

830L 830L

820L 820L

810L 810L

800L 800L

790L 790L

780L 780L

Legend

Open drives/unfilled stopes Backfilled drives

Backfilled areas Ore, left during mining

Un-mined stopes Pillars, not mined

Drilled, but un-mined CRF - Cement Reinforced Fill

6220 6225 6230

6280 62856230

66506615 6620 662565506480

6445

6505 6510

6395 6400

830

Acc

815 W

800 W

6415 6420 6425 6430 6435 6680 6685 6690 66956580 6585 6590 6595 6600 6605

Daybreak East & West

6520 6525 6555 65756320 63256295 6300 6305 633563106235 6450

6655

65456415 655564906455 6475 64806460 6500

654564856460 6465 6470 6480

6530 6535

65306475 65156495 6610 6630

6690 66956665 6670

64906380

6360 6365 6370 6375 66856460 6465 6470 6475 6630 6635

66356535 6540 6615 6620 6625

666065956530 6535

6560 6565

6225 6230 6235 6240 6610658065056435 65206195 6200 62056180 6185 6190 6210 6215 6220 6265 6270 6275 6280 6285

N

6100 6105 6110 6115 6120 6125 6130 6135 6140 6145 6150 6155 6160 6165 6170 6175 6640 6645

W

63256320 6675 6680660563806295 6300 6305 6310 6315 6385 6390 6395 6420 6425 6575 65856355 6555 6560 6565 65706415 6525 66006450 6455

6275 6280 6285 6290 6405 6410

65906345 63506330 6335 6340 6510 65156400

6455 65006190 6195 6200 6210 6215 6550

62906245 6250 6255 6260 64306405 6490 6495 6500 6540 65456410 6440 6445 6485

6330 6340 66756100 6105 6110 6115 6120 6125 6130 6135 6140 6145 6150 6155 6160 6165 6170 6175 6180 6440 64456185 6260 6265 6270

6340

6665 667065706345 6350 6355 6360 6365 6370 6375 6640 6645 6650 6655 6660

800

Acc

815

Acc

64006385 6390 63956315

6275 63106240 62706255 6330 63506320 63256315 63356295 630062906195 6225 6405634563056235 6250 6260 636063556190 6200

W

61556120 6130 61456140 6160 6180615061256100 6105 6110 6115 6135 6165 61756170 6185 6655 6660 668066706640 664565856580 6600 66506510 65256410 6605659565906565 65756210 626562456215 6220 6690

E

6630 669566856675666566356430 6520651564506440 66106375 6540 65506425 6495 656065056435 6470 64856465 6570 662566206390 6420 661563856370

6205

CRF

845H

W

875H

W

860H

W

890

HW

845

Acc

860

Acc

875

Acc

890

Acc

905

Acc

63806365

6240 6245 6250 6255

6205


6

Figure 4: Correnso Development – Plan View (overlaying property boundaries)

Main (# 1) vein

#7 South vein

Access spiral, ore/waste passes, and ventilation rises

844 Development drive

Access and ventilation drives

#5 vein

Daybreak development

Empire/Christina development

#4 North vein

#8 North vein


7

Figure 5: Correnso Development – Long Section View (left to right: south to north)


8

5. BACKFILLING AND COMPACTION OF STOPES

(Consent conditions: Correnso c.25c, SUPA c.19c) All stopes extracted to date are backfilled as is dictated by the mining method and conditions. Compaction occurs during backfilling by the machine placing the fill in the stope, then continues with subsequent operations of heavy machinery on top of the backfill. Historically this gives good compaction and the high clay-content of the fill provides a good binding medium.

6. GROUND CONDITION REVEALED BY EXCAVATIONS

(Consent conditions: Correnso c.25d, SUPA c.19d) Ground conditions for Correnso are mostly as expected. Q-value estimates are from 1 to 80 representing rock mass categories Poor to Very Good according to Barton’s (1974) ground support guidelines. Localised areas of poorer ground are encountered relating to intersecting structures and converging veins. The northernmost extents of Correnso have mined the #4-vein, a different vein zone to the main #1-vein. The separation between the two systems is marked by the “Quartz-Calcite fault”, a northeast-trending steeply-dipping zone of late-stage quartz and calcite veining which is strongly jointed with local cavities. Where the Correnso veining continues north of the quartz-calcite fault (between the 795 and 840 levels) it dips at a relatively shallow angle (45 – 55 degrees) to the east, in contrast with the rest of the ore-body which is more-or-less sub-vertical in aspect. The rock mass beyond the immediate hanging wall of the #4-vein is locally heavily sheared and this has meant a higher level of support by way of extensive cable-bolting has been needed. Production from this zone has necessitated short stope-panel lengths. Production from the #4-vein was virtually completed by the end of 2016 with very few stability issues. As stopes are completed the areas have been tight-filled. Daybreak ground conditions are similar to Correnso. The most significant areas of poor ground encountered in Daybreak development are related to the intersection of the quartz-calcite fault, the quartz-calcite fault is also intersected by Correnso development as mentioned above with a similar effect on ground conditions. Development commenced late in 2016 towards the Empire and Christina Vein systems. Rock mass conditions encountered to date are mostly Good to Very Good. Areas of poor ground when encountered are relatively restricted in extent and do not extend for more than 25 – 30 m along strike. Additional ground support (shotcrete and/or cable bolts) is installed in accordance with site standards and sound mining procedures. The areas encountered to date are all part of scheduled stope panels which are backfilled immediately as part of the stope cycle and would not be expected to have significant stability issues associated. Additional cable bolts are installed as determined by the geotechnical engineer where there are intersecting discontinuities with wedge potential. This is also in accordance with standard practices.


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7. MONITORING AND MEASURES FOR STABILITY

(Consent conditions: Correnso c.25e, SUPA c.19e) Multipoint Borehole Extensometers (MPBX) were installed during the early stages of mine development on the 795, 810, 825, 855 and 900 levels. The instruments are all installed in the intersections between the access and the main (#1-vein) ore-drives as representing the widest openings on the vein, as well as being the areas expected to see the most induced stresses as mining retreats towards the accesses. The MPBXs are inserted and grouted into up-hole boreholes and measure micro-displacements as low as 0.1 mm between “anchors”. The MPBXs utilised at Correnso have anchors at 1, 2, 3, 4, 6 and 8 m up the drillholes. Additionally, five 2-anchor “clock-it” extensometers are installed into the backs of the 915 level with anchors set at 2.5 m and 6 m up the holes. None of the above instruments showed any indications of significant ground movement or stress concentrations. As stoping occurred on the lower levels of Correnso the MPBXs on the 795, 810 and 825 levels have been lost, as expected. Readings prior to the MPBXs being destroyed indicated overall stable conditions. A micro-seismic monitoring system is installed (as per consent condition 23d) to provide additional reassurance that mining activity would not be causing instability. Micro-seismicity can be basically described as micro-earthquakes less than 0 magnitude, too small to be felt on surface but detectable by sensitive equipment located underground. The purpose of the seismic system is to monitor regional stability and the rock mass response to mining activities in the critical areas. Given the shallow depth of stoping and a relatively benign stress regime, the seismic system is not expected to record many non-blasting related seismic events. The maximum horizontal stresses pre-mining at 300 m depth are measured at 22 MPa; maximum vertical stresses (from the weight of the overlying rock) are around 15 MPa. These stresses are well below the 60 to 120 MPa average range of measured strengths of the rock mass that hosts the Correnso ore body. It is generally accepted in industry that event magnitudes of:

Magnitude Potential impact

mL 0.0 does not impact on operations

0.0 < mL 0.5 could potentially impact on operations, but typically marginally.

0.5 < mL 1.0 could impact on operations and even cause damage if

sufficiently close to workings.

1.0 < mL 2.0 could require special energy absorbent support systems

mL > 2 definitely requires special energy absorbent support systems.

The agreed critical magnitude for Correnso is a conservative ML = -0.5. Any seismic event of ML = -

0.5 and above are thus defined as an "anomalous result", and has to be reported to the HDC on a

monthly basis and the following details are required:

Event magnitude and location coordinates.

Image plot of the seismic events that includes existing openings and significant geological

structures.

Explanation of the probable cause of the seismic events.


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Levels of seismicity are overall low and there have only been a few reportable events during the

year. The reportable events above mL-0.5 do not show any clustering or trends and most of the

readings are well away from mine activity. There have been no volumes of unusual activity reported

by the seismologists who monitor the data, nor any volumes of unusual magnitude events.

8. MINING CONFINED TO CONSENT BOUNDARIES

(Consent conditions: Correnso c.25g, SUPA c.19g) Figure 6 displays the current mine development overlying an aerial projection, with the CEPPA and SUPA boundaries superimposed. All current Correnso works are entirely within the CEPPA consent boundary, and the SUPA boundary was not crossed during the year.


11

Figure 6: Correnso Development – Plan View (with CEPA and SUPA boundaries)


12

9. REVIEW OF CONSENT CONDITION REQUIREMENTS

a) Mining methods used require stope voids to be backfilled All stopes are backfilled as is required for the Avoca mining method (pictorial

representation in Appendix A).

b) Limits to upper levels of stoping The uppermost level on which stoping has been carried out by the end of 2016

was the 915 (900 – 915); the first stope blasts in this level were in the last week of the year.

c) Backfilling where required by geotechnical conditions Refer Section 5.

d) Seismic monitoring and rock movement monitoring Refer Section 7 above for monitoring systems.

e) Grouting of surface-drilled holes No surface-drilled exploration has been undertaken over Correnso during the

reporting period.

f) Interception of surface-drilled holes with water flows, and their treatment Two surface drilled holes have been intersected by Correnso development during

the period. All holes were assessed in accordance with Standard Operating Procedures (“Management of Intersecting Surface Diamond Drillholes”), and grouted where necessary within 36 hours. One low-flowing hole proved problematic to seal had to be re-grouted, then adjacent split-sets became a conduit and also had to be grouted to achieve an adequate seal. Refer Appendix C for details.

g) Works confined within consent boundaries Refer Section 8 for work locations.

10. CONCLUSION

OceanaGold believes it has fully complied with Conditions 25 (of HDC LUC 202.2012) and 19 (of HDC LUC 202.2016) and that the risk of ground surface instability is extremely low due to the geology of the area and best practice underground mining methodologies which have been employed.

11. REFERENCES

Dunn, M. 2014. Correnso Stage 2B Geotechnical Study. NEM013. Internal Newmont Report prepared by SRK Consulting (Australasia). Barton et al (1974). Barton, N., Lien, R. and Lunde, J. 1974. Engineering classification of rock masses for the design of tunnel support. Rock Mech., May. 189-236. CKL (Pagan M), June 2015. Correnso Mine Waihi Report. Survey Verification Report for Hauraki District Council. Mining One (Fuller, P), February 2015. Verification of CEPA underground mine workings relative to cadastral boundaries on the surface. Report for Hauraki District Council.


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14

Appendix A

Modified Avoca Technique


15

Schematic of Modified Avoca Technique

1 Drill drive access 2 Production drilling

3 Production blasting & bogging 4 Backfilling

5 Blasting & bogging over backfill 6 Progressive blasting/bogging

7 Multi-level production/backfill


16

Appendix B

Surface Drillholes Intersecting Workings


17

Hole ID Level Drive E N mRL Date

intersected Pickup

Grouting status

Comments

CGD008 810 C4-FW 396488.5 643473.4 821.4 13/06/2015 Estimated Not grouted Hole dry - no evidence of being a water conduit at this level: no Fe staining

UW320 912 ACC 396432.0 643265.1 917.8 13/04/2015 Surveyed Not grouted Hole dry

UW348 900 C1-N 396520.5 643263.4 907.6 14/12/2015 Estimated Grouted Trickling water which ceased within a day - grouted 16/12/2015

UW 358A 900 C1-S 396586.7 643035.2 910.6 27/07/2016 Estimated Grouted Low flow, originally grouted within 12 hours, re-grouted after 36 hours. Surrounding split sets grouted as were acting as a conduit. Flow was approximately 1ltr/min.

UW365 810 C4-FW 396488.4 643474.8 821.4 9/06/2015 Estimated Not grouted Hole dry

UW368 825 C7-S 396515.3 643114.2 833.1 26/08/2015 Surveyed Grouted Minor flow - hole re-grouted 16/12/2015

UW386 915 ORE PASS

396482.3 643218.5 914.9 4/02/2015 Surveyed Not grouted Hole dry - now in ore pass

UW390 840 C1-S 396541.4 643199.0 844.1 25/03/2015 Surveyed Not grouted Hole dry - no evidence of being a water conduit at this level: no Fe staining

UW393 840 C4-HW 396472.9 643416.3 851.4 16/08/2015 Estimated Not grouted Hole dry

UW402 953 CDD 396449.3 643126.9 930.5 17/12/2014 Surveyed Grouted Hole was producing minimal water for only a few hours

UW402 855 C7-S 396515.0 643092.4 864.6 18/10/2015 Surveyed Not grouted Dry - second time intersecting hole with development - was grouted on the 953

UW374 860 DB-HWW 396237.7 643120.7 871.9 16/12/2016 Surveyed Not grouted Hole was dry, no indication of previous water – i.e. no Fe staining, etc.

Overleaf is plan view of Correnso and Daybreak development with surface drillholes intersected and their pierce points (no surface holes have yet been intersected by Empire development). Green points indicate the drillhole collars in view while the red points indicate the approximate intersection point of surface drillholes with development.


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Documents

Correnso/SUPA Stability 2016 Annual Report · A - Modified Avoca Technique (graphic) B - Surface Drillholes Intersecting Workings ... LUC 202.2016 (SUPA) Condition 19 – Surface