Investigation of old mine workings

Lot 8 and lot 141 Wilton Drive East Maitland

Cole-Clark Mine Subsidence and Mining Engineering Pty Ltd

MINING ENGINEERING MINE SUBSIDENCE MINE GROUTING SUBSIDENCE REMEDIATION

CONTENTS

1.0 INTRODUCTION

2.0 BACKGROUND

3.0 MINE WORKINGS

4.0 SUBSIDENCE ADVISORY NSW AND MAITLAND COUNCIL

5.0 SITE INVESTIGATION

5.1 SITE INVESTIGATION LOT 8

5.2 SITE INVESTIGATION LOT 141

5.3 SURFACE DEVELOPMENT

6.0 CONCLUSION

REFERENCES

APPENDICES

Appendix A – Mine Subsidence Board approval lot 42 DP 846326 22 September 2009

Appendix B – Mine Subsidence Board stamped cover sheet Development Application lot

42 DP 846326 20 September 2016

Appendix C - Survey of boreholes lot 8 and lot 141

Appendix D – Summary of bore logs lot 8 and lot 141

This document shall remain the property of Cole-Clark Mine Subsidence and Mining Engineering Pty Ltd. The document is

produced for the sole benefit of the client and may only be used for the purpose for which it was commissioned and in

accordance with the Terms on Engagement. Unauthorised use of this document in any form whatsoever is prohibited. The

document shall not be used, sold, transferred or copied in whole or part other than by agreement with Cole-Clark Mine

Subsidence and Mining Engineering Pty Ltd. Cole-Clark Mine Subsidence and Mining Engineering Pty Ltd does not assume any

responsibility or liability whatsoever to any third party arising out of any use or reliance by the third party on the content of this

document. The findings in this report represent a reasonable interpretation of the general site conditions, however, it should

not be considered that the findings represent the site at all points.





1.0 INTRODUCTION

This report presents the outcomes of a site investigation of old and abandoned mine workings at lot 8

DP855275 and part lot 141 DP1225076 Mount Vincent Road and Wilton Drive East Maitland NSW

2323. The work was commissioned by GHT Holdings Pty Ltd to enable Subsidence Advisory NSW to

approve a staged development for Seniors Living.

The report is only applicable to surface residential development of lot 8 and part lot 141 and is not to be

relied upon for any other locations. Matters relating to construction, such as a geotechnical site

classification, are not intended to be covered within the scope of this report.

2.0 BACKGROUND

Lot 8 DP855275 and part lot 141 DP1225076 are located within the Maitland Local Government Area on

the southern side of Wilton Road, East Maitland.

The site is located within the East Maitland mine subsidence district and Subsidence Advisory NSW’s

(formerly Mine Subsidence Board) approval is required for subdivision or surface development. Surface

development has occurred in the general area (Fig 1). It is proposed to develop residential structures on

the lots for Seniors Living along with a larger community complex.

Lot 8 is around 6157m2 in area and slopes around 1 in 100 to the south. The larger lot 141 slopes to the

south but has a varied topography due to drainage gullies.

Fig 1: Location of lot 8 and lot 141 at East Maitland

Subsidence Advisory NSW has provided a plan that indicates lot 8 and lot 141 are partially undermined

old shallow mine workings in the Rathluba Seam.

Subsidence Advisory NSW and Maitland City Council have approved the development of a house and

detached garage on lot 141. Maitland City Council has also approved subdivision of lot 8. The

subdivision has not proceeded as the lot will be developed in its entirety to provide for Seniors Living.

Lot 8

Lot 141





Site investigation initially commenced in 2012 and there is a large amount of background information.

This information was reviewed in preparation for the detailed site investigation of lot 8 and part of lot

141 and the identification of the western boundary of the mine workings on lot 141 that are the subject

of this report.

Fig 2: Proposed Staged development for Seniors Living

The initial stages of the development involve establishing access through lot 8 into lot 141 to enable

surface development to the west of the old mine workings. Structures will also be built on lot 8 and in

the northern section of lot 141.

The mine workings increase in depth to the east and further site investigation is proposed at a time

when the staged development extends to that area.

3.0 MINE WORKINGS

Lot 8 and Lot 141 are partially underlain by old and abandoned mine workings in the Rathluba Coal

Seam of the Tomago Coal Measures. The mine workings were mined by Rathluba Colliery and Rathluba

No2 Colliery.

The mine plan indicates that the area was worked by the Bord and Pillar method, which involves the

development of a series of headings and cut-throughs that usually leave rectangular shaped pillars of





coal to support the mine roof during the development of panels. These pillars can then be extracted, in

what is referred to as secondary or pillar extraction, leaving small sections of coal intact to control the

collapse of roof material. Extraction rates can vary but it is likely +80% of coal would be extracted during

secondary extraction creating a goaf area. Whilst the goaf area will be filled with crushed coal and fallen

roof material it is possible there may still be some voids. The Record Tracing indicates first workings only

were completed beneath lot 8 and lot 141

Records indicate the Rathluba Seam had working sections ranging from 5’ (1.52m) to around 8’ 6”

(2.61m) due to varying bands of dirty coal that affected coal quality. Based on references the total seam

thickness is around 3.3m and the seam dips at approximately 1 in 12 to the south-east.

Fig 3: Mine workings and Rathluba Seam section

Based on the Record Tracing there are no shafts or drifts on lot 8 and lot 141. A mine entry and shafts

exist to the south of the lot 141 boundary.

This report concentrates on the western and northern extent of the mine workings on lot 141. The mine

workings to the east will be assessed when the staged Seniors Living development is scheduled for that

area.





4.0 SUBSIDENCE ADVISORY NSW AND MAITLAND COUNCIL

The Mine Subsidence Compensation Act 1961 provides an Act to make provision for and in respect of a

scheme for the payment of compensation where improvements on the surface or household effects are

damaged by subsidence following the extraction of coal or shale.

Section 15 Mine Subsidence Districts of the Mine Subsidence Act allows the Governor to proclaim a

Mine Subsidence District. This enables Subsidence Advisory NSW to mitigate claims on the Mine

Subsidence Compensation Fund. Under Section 15(2A), the Subsidence Advisory NSW’s approval is

required to alter or erect improvements within a mine subsidence district or to subdivide land therein.

Surface improvements outside a Mine Subsidence District are automatically covered by the Mine

Subsidence Compensation Act.

Under Section 15(3) The Board may grant its approval either subject to conditions or unconditionally or

may refuse its approval. Such conditions may include conditions relating to the class or nature of

improvements, the height, weight, type of material, number of storeys and method of construction of

any improvements within the district. Such conditions may vary according to the location, class or

nature of such improvements.

Subsidence Advisory NSW has recognised grouting of old shallow mined workings will enable mine

subsidence to be managed such that structures will remain safe, serviceable and repairable. It is

acknowledged there may still be a small amount of residual subsidence that could occur after grouting.

Additional structural design would not be required where this was within design parameters of AS2870

and the Building Code of Australia.

Lot 8 and lot 141 are located within the East Maitland mine subsidence district proclaimed 20 February,

1974 and the Subsidence Advisory NSW’s approval is required for subdivision and surface development.

On 11 February 2014, Maitland Council granted consent of DA12-1481 subject to specified conditions

for lot 8 to be subdivided into six (6) residential lots including an access road. There were no conditions

relating to Subsidence Advisory NSW approval.

Fig 4: Maitland Council approved subdivision of lot 8





On 21 January 2009, Subsidence Advisory NSW issued a conditional approval of Building Application

TBA09-09564N1 for lot 42 DP 846326 Mount Vincent Road East Maitland. Maitland Council

subsequently granted conditional consent of DA09-451 for the erection of a dwelling and detached

garage on part of lot 141 DP1225076 (formerly lot 42 DP846326) on 22 September 2009. Schedule B

indicated that attached information from Subsidence Advisory NSW needs to be taken into account for

the construction certificate. On 20 September 2016, Subsidence Advisory NSW extended the approval

for a further 2 years following a request from ACM Landmark dated 31 August 2016. A copy of

Subsidence Advisory NSW‘s approval is attached as Appendices A and B.

Fig 5: Approved development of a dwelling and garage lot 141.

5.0 SITE INVESTIGATION

Site investigation commenced with a review of available information and a surface inspection.

Following a meeting between Mine Subsidence and Mining Engineering Pty Ltd and the owners on 28

April 2017, a decision was made to further investigate the old mine workings to provide information to

Subsidence Advisory NSW for the approval of the proposed Seniors Living complex. The site work took

place between 6 February and 13 August 2017.

There have been a number of previous investigations and reports which provided useful information

regarding the status of the mine workings in the immediate area, including;

1) Urban Capability Assessment lot 8 DP 855275 Wilton Drive East Maitland, Geotech Solutions GS

Ref 473-002/1 dated 4 February 2010

2) Test Hole logs 13.08.2012 Cardno Geotech Solutions GS1358 13-15 August 2012

During 13 – 15 August 2012, Cardno Geotech Solutions drilled and logged 17 closely spaced

boreholes to investigation the mine workings. Both solid coal and voids were encountered.





3) Urban Capability Assessment lot 42 DP 846326 and lot 1012 DP 1103879 Mount Vincent Road

East Maitland, Cardno Geotech Solutions CGS Ref 1435-001/2 dated 22 August 2012

This report detailed development issues for the site and attached the Brunskill Pty Ltd report;

Mine Workings underlying and adjacent to lots 123 and 124 DP 862386, lots 41 and 42 DP

846326 and specifically lot 8 DP 855725 – Wilton Drive East Maitland. The Cardno Geotech

Solutions report noted that further geotechnical investigation is required to provide advice in

relation to shallow mined working

4) Geophysical imaging of abandoned mines, East Maitland

MG2013_046_Cardno_East_Maitland_Report_v3 Moultrie Group / Cardno Geotech Solutions

August 2013

Ground Penetrating Radar (GPR) was applied over lot 8 with the outcome that any further GPR

survey should concentrate on the south-east corner of the site. Radar reflections on the

western boundary were attributed to man-made structures.

5) Mine Workings underlying and adjacent to Lot 42 DP 846326 Wilton Drive – Updated Report,

Brunskill Pty Ltd, BMPR935A_070514 7 May 2014

The report advised previous research had been conducted in January 2010 and December 2012

to determine the location of the mine workings underlying and adjacent to lot 42 DP 846326

and lot 1012 DP 1103879. The report indicated that the location of the mine workings in the

Delta Record Tracing is considered to be in the order of +/- 10 metres accuracy. The report also

advised there is some potential for unchartered workings in areas shaded on Drawing No

CARDNO-01 and included a copy of the drawing below dated 6 May 2014. Brunskill Pty Ltd also

provided Attachment B: Record Tracing Check sheet which summarised RTs relevant to the

area.





6) Douglas Partners email to ACM Landmark dated 10 February 2016. Douglas Partners attached

the following two drawings and indicated they had encountered voids beyond the previously

mapped workings.

- 81879.00.D.001.dftA. Bore location plan and depth of cover

- 81879.00.D.002.dftA. Bore location plan and record trace

7) Report on Mine Subsidence Investigation Douglas Partners Project 81879.00 March 2016

This report provided details regarding the drilling of Boreholes L101 to L112, L201 to L212, L301

to L310 and 1001 to 1016 and outcomes.

It is not necessary to repeat details from these reports but the background information was considered

in undertaking the site investigation detailed in this report. The documents were provided by the

owners representative, ACM Landmark, and copies can be provided upon request.

In the reports referenced, Record Tracings and other information were utilised to ascertain the possible

location of the old mine workings. A reasonable level of confidence can be placed on Record Tracings,

particularly when combined with site investigation. However, with old mine workings there can be the

possibility of unrecorded mine workings or inaccuracy due to the relationship between the underground

mine workings and surface cadastre. Drilling provides specific information at the location drilled and

may not identify every detail or extent of old mine workings.

Boreholes were monitored during drilling to record conditions encountered, the depth to the coal seam

floor and whether any ‘drill drop’ occurred. The latter indicates the presence of a void. Bore log

information provided by BFG Daracon Pty Ltd is summarised in Table 1. Drilling was undertaken using a

Boart Longyear Diamond Rotary Drill Rig. Boreholes were not cored and therefore best estimates of

strata and thickness, including voids, is made based on observations during drilling.

A total of 215 boreholes have been drilled across lot 8 and lot 141 since 2012 to investigate the old mine

workings. The boreholes are summarised in Table 1.

Table 1: Summary of boreholes

Boreholes Organisation Date total

BH001 – BH017 Cardno Geotech Services 13-15 August 2012 17

L101 - L112; L201 -

L212; L301 - L316

Douglas Partners 9 - 11 March 2015 34

1001 to 1016 Douglas Partners 11 January 2016 16

D400 – D478 Mine Subsidence and Mining Engineering 6 -14 February 2017 79

D479 – D509 Mine Subsidence and Mining Engineering 20 -23 February 2017 31

A1 to A20 Mine Subsidence and Mining Engineering 12-13 April 2017 20

N01 – N18 Mine Subsidence and Mining Engineering 3 - 6 March 2017 18

TOTAL 215

Fig 6 shows the surveyed location of all boreholes drilled by Mine Subsidence and Mining Engineering

Pty Ltd as well as existing boreholes that were able to be identified. A larger plan is attached as

Appendix C.





Fig 6: Location of new and existing boreholes on lot 8 and lot 141

5.1 SITE INVESTIGATION LOT 8 DP855275

Site Inspection - A walkover of the site did not find evidence of recent mine subsidence features. No

openings to mine workings or obvious mining related potholes were evident and discussion with the

Subsidence Advisory NSW has indicated the lot has no history of mine subsidence. There were a number

of slight depressions in an area where drilling encountered broken ground and it is possible they may be

related to cracked strata associated with mine subsidence. A later inspection observed the depressions

to be holding water which indicates it may be part of a surface water flow channel or if subsidence

related they have possibly silted up.

Photos 1 and 2: Possible mine subidence feature

It is estimated that the mine workings were mined pre 1950. Based on bore log information in detailed

drill logs from 2012, the overlying stratum consists of around 0.3m topsoil, 0.7m sandy clay underlain by

interbedded sandstone and siltstone followed by the Rathluba Coal Seam. The floor of the seam is

siltstone/sandstone.





Information referenced, including the Subsidence Advisory plan in Figure 7 that highlights lot 8,

indicated that the mine workings were limited to the south-east corner of lot 8. In June 2013, Moultrie

Geology [4] undertook geophysical imaging of lot 8 using Ground Penetrating Radar (GPR). The

summary indicated that high amplitude reflections along the western boundary were as a result of man-

made structures such as the house at 8 Wilton Drive. The report indicated that high amplitude reflection

anomalies at the south-east corner of the site are caused by scattering of large air filled voids such as

abandoned bord and pillar mine workings.

Boreholes BH001 – BH017 drilled by Cardno Geotech Solutions [2] in August 2012 near the eastern

boundary of lot to define the mine workings encountered both voids and solid coal. Douglas Partners [7]

drilled 5 boreholes on the site in January 2016 with all boreholes encountering soft material or a void,

which demonstrated reported there were mine workings beyond those shown on the Record Tracing.

These location of these boreholes is shown in Figure 8.

Mine Subsidence and Mining Engineering Pty Ltd drilled a further 74 boreholes on lot 8 at strategic

locations to identify the status and possible extent of the mine workings. The boreholes were analysed

as the project progressed and this resulted in several stages of drilling following the approval of GHT

Holdings Pty Ltd. The boreholes were also located to assist with grouting of mine workings should this

be required. The outcome of the site investigation was that a greater amount of the site was

undermined than shown on the Record Tracing or anticipated from earlier reports.

Stage 1 Boreholes D454 – D479 6 – 14 February 2017 (26)

Stage 2 Boreholes D479 - D506 23 February 2017 (28)

Stage 3 Boreholes A01 - A20 12 – 13 April 2017 (20)

Fig 7: Mine Subsidence Board plan of mine workings





The surveyed location of the boreholes drilled on lot 8 is illustrated in Fig 8 with those boreholes where

there was a clear void highlighted in red and the boreholes that were solid coal are highlighted in green.

There were few boreholes where drilling was very soft but a void was not observed or the conditions

were difficult to interpret from drilling – D492, D502, D504, A13, A19. Of the 74 boreholes, a total of 45

or 61% encountered a void. The average void height was 0.95m. A summary from the bore logs

provided by the driller, including the presence of a void, is included in Appendix D.

A camera inspection of the mine workings was undertaken through a number of boreholes. It was

evident that slabs of roof material had collapsed into the workings and voids were observed. The

definition of the pillars and roadways was not clearly observed and therefore it is anticipated there may

have been some associated crushing or spalling of coal pillars.

Based on the site investigation of lot 8 DP855275 is it evident mine working are more extensive than

shown on the record tracing. The mine workings are shallow with a depth of cover ranging from 4m on

the western side to 11m at the eastern boundary. Remediation of the mine workings will be required

where residential structures are proposed.

Fig 8: Lot 8 DP 855275 Location of boreholes with voids shown in red.

5.2 SITE INVESTIGATION LOT 141 DP1225076

Site Inspection - A walkover of the site did not find evidence of recent mine subsidence features. No

openings to mine workings or obvious mining related potholes were evident.

The objective of the site investigation on lot 141 was to establish the western edge of the mine

workings and investigate the extent of mine workings in the northern section adjacaent to the southern

boundary of lot 8.

Approx location

BH001 - BH020





Douglas Partners [7] had drilled three rows of boreholes in an east – west direction across lot 141 in

February – March 2015 and a further 11 boreholes in the northern section of lot 141 in January 2016.

In February 2017, Mine Subsidence and Mining Engineering Pty Ltd commenced the drilling of 76

boreholes along the western edge of the mine workings utilising previous boreholes as a starting point

and in the northern section to investigate the extent and status of the mine workings. Boreholes were

spaced around 4m to 6m apart.

Stage 1 Boreholes D400 – D453 6 – 14 February 2017 (54)

Stage 2 Boreholes D507 - D509 23 February 2017 (3)

Stage 3 Boreholes N01 – N18 3 – 6 March 2017 (19)

Boreholes D400 – D432 were drilled along the westen boundary of the anticipated mine workings based

on Record Tracings and provided a reasonable confidence of the extent of the mine workings. Boreholes

at the southern end were observed to have water in them following drilling. A row of boreholes (D433

– D453) was then continued across the anticipated northern boundary of the mine workings to define

the possible northern extent of the workings.

Boreholes D507 – D509 and N01 – N18 were then drilled based on information from lot 8 that

suggested mine workings extended beyond the southern boundry of that lot. Douglas Partners [7] had

drilled boreholes 1014 – 1016 and L309 / L310 just north of this row and encountered voids in

boreholes 1016, 309 and 310. This drilling confirmed there are mine workings on lot 141 near the

southern boundary of lot 8. It is likely these mine workings are an extension of those under lot 8.

The surveyed location of the numbered boreholes on lot 141 is shown in Fig 9 and a summary from the

bore logs provided by the driller, including the presence of a void, is included as Appendix D. A larger

plan showing all the boreholes for lot 8 and lot 141 is included in Appendix C.

Fig 9: Location of boreholes on lot 141





A camera inspection of the mine workings was undertaken through a number of boreholes in the

northern area which showed voids and slabs of roof material had collapsed into the mine workings.

Figure 10 shows those boreholes where there was a clear void highlighted in red and those where solid

coal was encountered during drilling are highlighted in green.

Fig 10: Lot 141 boreholes with voids and western boundary shown.

Based on the information referenced and the site investigation of lot 141 it is unlikley there are mine

workings to the west of the blue line. The line provides a tolerance of around 10m from the predicted

mine workings although given the edge of the mine workings is irregular this distance is greater at some

locations. Drilling appeared to identify the northern extent of the mine workings on lot 141, however,





the demarkation became somewhat blurred by the mine workings that were not shown on the record

tracing and extend south from lot 8. The relationship between mine workings will become clearer when

grout flows between boreholes are monitored by camera.

5.3 SURFACE DEVELOPMENT

Lot 8 and lot 141 are located within the East Maitland mine subsidence district and Subsidence Advisory

NSW’s approval is required for subdivision and surface development. Most structures will be single

storey brick veneer on a slab to AS2870.

Lot 8 – The site investigation identified shallow mined workings beneath lot 8 and there are a number of

options so that residential structures built on lot 8 will remain safe, serviceable and repairable in the

event of mine subsidence. Options include,

• Grouting beneath dwelling footprints

• Structural Design

• Piering foundations for structures

Lot 141 - The site investigation has determed the likely western boundary of mine workings on lot 141

and a 10m ‘tolerance’ has been applied to establish the boundary. Structures to the west are unlikely to

be undermined and would be constructed to AS2870 and relevant building codes. As the edge of the

mine workings is irregular, there are some areas immediately to the east of the blue line that are not

undermined and development in this area should be considered on merit. The line passes through a

number of proposed building footprints and these can be reviewed and the blue line reviewed as the

staged development approaches these locations. There are mine workings along the northern section

and it is recommended options as required for residential structures on lot 8 apply to these locations.

Entry Road lot 8 and lot 141 and services - The entry road through lot 8 and across lot 141 to provide

access to the western area will be constucted of concrete. The depth the coal seam at this location on

lot 8 is around 8m deep and given the overlying strata it is recommended that the pavement be

designed to span a 5m pothole should it not be included in the remediation programme for the mine

workings. Similarly services will need to be designed to cater for mine subsidence if there is the risk of

ground movement.

6.0 CONCLUSION

Site investigation of old and abandoned mine workings beneath lot 8 DP855275 and part lot 141

DP1225076 Mount Vincent Road and Wilton Drive East Maitland has been completed. A total of 215

boreholes have been drilled.

Approval has been granted by Maitland Council for subdivision of lot 8 and by Maitland Council and

Subsidence Advisory NSW for a dwelling and detached garage on lot 141. The lots are to be

consolidated and developed for Seniors Living.

This report is submitted as supporting documentation to enable Subsidence Advisory NSW to consider

approval for the staged surface development of lot 8 and that part lot 141 for Seniors Living. Surface

development will consist primarily of single storey brick veneer residential structures constructed on a





slab in accordance with AS2870 and the Building Code of Australia with the exception of community

facilities which may be 2 storey. Residential structures will be designed so they remain safe, serviceable

and repairable in the event of mine subsidence.

Subsidence Advisory NSW’s approval is sought for surface development of lot 8 and part lot 141 with

development to the west of the blue line on lot 141 (Fig 10) only requiring design to AS2870 and

Australian Building Codes. Mine Subsidence and Mining Engineering Pty Ltd would be pleased to discuss

the outcomes of this report with Subsidence Advisory NSW or provide additional detail if required.

REFERENCES

[1] Urban Capability Assessment lot 8 DP 855275 Wilton Drive East Maitland, Geotech Solutions GS

Ref 473-002/1 dated 4 February 2010

[2] Test Hole logs 13.08.2012 Cardno Geotech Solutions GS1358 13-15 August 2012

[3] Urban Capability Assessment lot 42 DP 846326 and lot 1012 DP 1103879 Mount Vincent Road

East Maitland, Cardno Geotech Solutions CGS Ref 1435-001/2 dated 22 August 2012

[4] Geophysical imaging of abandoned mines, East Maitland

MG2013_046_Cardno_East_Maitland_Report_v3 Moultrie Group / Cardno Geotech Solutions

August 2013

[5] Mine Workings underlying and adjacent to Lot 42 DP 846326 Wilton Drive – Updated Report,

Brunskill Pty Ltd, BMPR935A_070514 7 May 2014

[6] Douglas Partners email to ACM Landmark dated 10 February 2016. Douglas Partners attached

the following two drawings and indicated they had encountered voids beyond the previously

mapped workings.

- 81879.00.D.001.dftA. Bore location plan and depth of cover

- 81879.00.D.002.dftA. Bore location plan and record trace

[7] Report on Mine Subsidence Investigation Douglas Partners Project 81879.00 March 2016

This report provided details regarding the drilling of Boreholes L101 to L112, L201 to L212, L301

to L310 and 1001 to 1016 and outcomes.





APPENDICES

APPENDIX A - Mine Subsidence Board approval lot 42 DP 846326 22 September 2009





APPENDIX B – Mine Subsidence Board stamped cover sheet Development Application lot 42 DP

846326 20 September 2016. This is now part of lot 141 DP125076.





APPENDIX C – Survey of boreholes lot 8 and lot 141





Appendix D – Summary of bore logs lot 8 and lot 141

VOID /

COAL

VOID

m

COAL (m) SEAM FLOOR

(m)

D400 Coal - 2.7 11.8

D401 void 1.1 11.1

D402 void 1.5 10.5

D403 Coal - 3.0 12.5

D404 void 0.9 10.7

D405 Coal - 1.7 10.3

D406 Coal - 2.8 9.8

D407 Coal - 2.8 9.8

D408 Coal - 2.9 7.6

D409 coal - 3.0 7.6

D410 Void? - Broken / soft 12.0

D411 void 0.2 12.1

D412 void 1.0 11.8

D413 void 0.7 10.7

D414 coal - 2.9 9.7

D415 coal - 3.0 9.5

D416 coal - 2.8 9.0

D417 void 0.6 9.8

D418 coal - 3.0 9.3

D419 coal - 3.0 9.5

D420 void 0.7 9.7

D421 void 0.8 10.0

D422 void 0.5 10.7

D423 void 0.8 10.6

D424 coal - 3.2 10.4

D425 coal - 3.0 10.5

D426 coal - 3.0 9.5

D427 coal - 3.3 9.3

D428 coal - 3.0 9.6

D429 void 1.2 9.5

D430 coal - 3.0 9.3

D431 coal - 3.0 9.0

D432 coal - 3.0 9.0

D433 coal - 2.8 10.6

D434 coal - 2.9 10.9

D435 coal - 3.0 11.5

D436 void 2.1 11.4

D437 soft 0.0 Soft / firm / air loss 11.5

D438 coal - 2.1 11.6

D439 coal - 3.0 10.5

D440 coal - 3.0 13.0

D441 coal - 2.9 13.2

D442 coal - 3.0 Coal – soft / rib? 13.5

D443 void 1.8 13.6

D444 coal - 3.2 13.8

D445 coal - 3.2 14.8

D446 coal - 1.6 14.1

D447 coal - 3.0m very soft / push

through

13.5

D448 void 1.5 13.5

D449 void 0.5 13.3

D450 coal - 3.0 13.5

D451 coal - 3.0 13.5

D452 coal - 3.0 13.4

D453 coal - 2.9 13.3

D454 void 0.2 13.0





D455 void 0.8 13.0

D456 void 0.5 13.0

D457 void 0.6 12.1

D458 coal - 3.1 12.2

D459 coal - 3.3 11.5

D460 void 0.2 11.0

D461 coal - 3.0 11.0

D462 void 0.3 10.4

D463 void 0.3 10.3

D464 void 0.3 9.8

D465 void 0.4 9.2

D466 void 1.0 8.7

D467 void 1.0 8.7

D468 void 1.0 8.5

D469 coal 3.0 8.5

D470 coal - 2.8 13.6

D471 coal - 2.8 13.2

D472 coal - 3.0 13.0

D473 void 0.4 12.8

D474 void 0.5 12.6

D475 void 0.7 12.1

D476 void 0.5 11.8

D477 coal - 3.0 very soft 11.5

D478 coal - 3.1 11.2

D479 void 0.7 10.5

D480 void 0.5 10.3

D481 coal - 2.9 very soft 10.1

D482 coal - 3.1 10.1

D483 void 1.0 10.0

D484 void 0.7 10.6

D485 void 0.9 10.8

D486 coal 3.1 10.5

D487 void 0.7 Cracked strata with

voids

10.3


voids

10.3

D489 void 0.4 13.1

D490 void 0.5 13.0

D491 void 0.6 12.9

D492 soft 0.0 Push through 12.8

D493 coal - 3.0 12.5

D494 coal - 3.0 coal push through 12.5

D495 coal - 3.1 12.4

D496 void 0.2 12.2

D497 coal - 3.0 12.5


voids

12.5

D499 void 0.3 10.8

D500 coal - 3.5 10.5

D501 void 1.0 9.3


D503 void 0.3 8.8


D505 void 1.2 8.4

D506 coal - 2.7 8.0

D507 coal - 3.2 13.7

D508 void 0.5 13.6

D509 void 1.1 12.6

N1 void 1.6 13.0

N2 void 0.5 12.8





NOTE: Depths and void heights are approximate.

N3 void 1.2 12.6

N4 void 0.2 11.9

N5 coal - 3.0 11.8

N6 coal - 2.7 12.0

N7 void 1.1 11.9

N8 void 1.0 10.0

N9 void 2.5 10.0

N10 void 0.2 9.8

N11 void 1.0 9.0

N12 void ? crack at 3.5m 10.0

N13 void 1.8 9.5

N14 void 3.0 10.5

N15 coal - 3.0 10.2

N16 void 0.2 10.1

N17 void 0.5 9.5

N18 void 0.1 10.0

A1 void 0.8 11.0

A2 void 1.5 11.0

A3 coal - 6.0 Error? 11.0

A4 void 2.2 10.5

A5 void 3.0 10.5

A6 coal 6.0 10.0

A7 void 2.0 9.0

A8 void 1.0 7.5

A9 void 3.5 8.0

A10 coal - 4.0 Error? 8.0

A11 void - Rubble 12.0

A12 void 1.0 12.0


A14 void 3.0 12.0

A15 void 1.5 12.0

A16 void 1.0 12.0

A17 coal 1.0 12.0

A18 coal - 5.0 Error? 12.0


A20 void 1.5 11.0

SITE INVESTIGATION OF OLD MINE WORKINGS PART LOT …

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