EIS 296

Report, geotechnical investigation, lowwall & spoil pile stability,

proposed surface coal mine, Mt. Thorley, N.S.W. for R.W. Miller

& Co. Pty. Ltd.

MSW DEPT PRIMARI iUSTR1ES

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D*ES a. MOICME CONSULTANTS IN THE ENVIRONMENTAL

AND APPLIED EARTH SCIENCES

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1 1 I I I REPORT

GEOTECHNICAL INVESTIGATION

ILOWWALL & SPOIL PILE SThBILITY

PROPOSED SUEFACE COAL MINE

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MT. THORLEY,

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R.W. MILLER & CO. PTY LTD.

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I DRAFT I

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I DAMES & MOORE

I JO B NO: 10236-00170

DATE: JANUARY 1978

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PERTH MELBOURNE SINGAPORE DAMES & MOORE JAKARTA

CONSULTANTS IN 'THE ENVIRONMENTAL AND APPLIED EARTH SCIENCES LONDON TOKYO MADRID VANCOUVER TEHRAN TORONTO JOHANNESBURG CALGARY

PRINCIPAL CITIES IN THE U.S.A.

7 MYRTLE STREET. CROWS NEST, N.S.W. 2065. AUSTRALI A

TELEPHONE 929.7744 TELEX 21378 CABLE AODRESS DAMEMORE

January 24 1978

R W Miller & Co Pty Ltd 237 King Street NEWCASTLE N S W 2300

Attention: Mr Peter Murray General Manager - Mining

Dear Sir

Enclosed are five draft copies of our report " Geotechnical Investigation, Lowwall and Spoilpile Stability, Proposed Surface Coal Mine, Mt. Thorley, N S WI'.

This is the second of two reports issued following our geotechnical investigations at Mt. Thorley. The final version of the first report on highwall stability was issued on January 23 1978. We would be pleased to receive any comments you might have on the contents of the draft. If we have not received any comments by February 7 1978 we will issue the reports in final form unchanged from the draft.

Yours faithfully DAMES & MOORE

I-,&. A C LEGGO Principal-in--Charge

MEMBERS OF THE ASSOCIATION OF CONSULTING ENGINEERS AUSTRALIA

TABLE OF CONTENTS

Page

1.0 INTRODUCTION 1 1.1 General 1.2 Proposed Development

2.0 GEOTECHNICAL STUDY 2 2.1 Objectives 2.2 Method of geotechnical study

3.0 MINE PLAN 5

4.0 SITE CONDITIONS 6 4.1 Geology 4.2 Hydrology

5.0 HIGEWALL STABILITY - WESTERN ZONE 6

6.0 LOWWALL STABILITY 7 6.1 General 6.2 Lowwall stability - Eastern zone 6.3 Lowwall stability - Western zone

7.0 SPOIL PILE STABILITY 9 7.1 Nature of spoil 7.2 Geometry of spoil piles

7.2.1 Spoil in Open Cut 7.2.2 Spoil in permanent spoil piles

7.3 Nature and slope of spoil pile floor 7.4 Water conditions

8.0 PIT FLOOR STABILITY 12

9.0 GROUNDWATER CONDITIONS 13 9.1 General 9.2 Estimated groundwater flows into pit

10.0 OVERBURDEN EXCAVATION CHARACTERISTICS 14

11.0 CONCLUSIONS AND RECOMMENDATIONS 15 11.1 Highwall stability - Western zone 11.2 Lowwall stability - Eastern zone 11.3 Lowwall stability - Western zone 11.4 Spoil pile stability 11.5 Groundwater inflows 11.6 Overburden excavation

LIST OF FIGURES 19

Figures 1 to 10

APPENDIX 20 to 24

LIST OF APPENDIX FIGURES 25

Figures Ala to A21

Eli 1.0 INTRODUCTION

1.1 General

Thisis the second of two reports presenting the results of geotechnical

studies carried out to obtain data on:

- Stability of highwalls, lowwalls and spoilpiles

- Groundwater regime and effect on mining

- Characteristics of material with respect to drilling, blasting, excavation.

- In order to facilitate mine planning studies, our initial report, on stability

I of highwalls in the eastern Zone, was submitted separately, on 14 November

1977. This report presents the results of the remaining aspects of the study.

by Mr Peter Murray The work performed during this study was authorized under

R W Miller & Co Pty Ltd purchase order no MT C 0076096. The original scope

of the study was outlined in our proposal dated 11 February 1977. The scope

was later expanded to include a geotechnical study of the western zone.

I It should be noted that some of the following sections of this report are

identical to those under the same heading in the first report. They are

repeated here for the sake of completeness.

1.2 Proposed Development

The Mt Thorley lease area is shown on Figure 1. It is an area of about 25

square kilometrs, located about 11 km southwest of Singleton.

Current plans involve initial mining in the eastern zone, commencing

immediately to the west of the "Mt Thorley Fault", with a possibility of

later mining in the western zone. The seams to be mined in the eastern zone

are the Glen Munro/Woodlands Hill, the Mt Arthur and the Piercefield, while

the Whybrow seam would be mined in the western zone. The two major seams,

theGlen Munro/Woodlands Hill and the Piercefield, average about 8 m and 16 m

in thickness, respectively.

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Initially, the Glen Munro/Woodlands Hill seam will be mined as a single

seam operation, on a contract basis. Mining will commence at the 8 m cover

I line and overburden will be dumped in permanent spoil disposal areas to the

east of the "Fault". This will allow later access to the deeper seam. The

seam will be mined on a long north-south face with advance down dip to the

1 west at the rate of about 30 m to 50 m per year. This operation will be

aimed at production of about 400,000 to 600,000 tonnes of washed coal per

I year.

I It is anticipated that at the end of the contract period, about three years,

the highwall will be a maximum of 25 m in height. The mining operation in

I the eastern zone to which this report primarily relates, however, is the

multiple seam mining of the Glen Munro/Woodlands Hill, Mt Arthur and Pierce-

field seams. This operation will commence some time after commencement of

I the contract upper seam operation.

2.0 GEOTECHNICAL STUDY

2.1 Objectives

The primary objective of the geotechnical study was to obtain representative

I data on the geotechnical parameters which will have an influence on the

design and operation of the open-cut mine. These parameters include:

I - GrouxLdwater regime - existing levels, fluctuation with seasonal rainfall; estimation of aquifer properties

I - Engineering geology of zone to be mined - presence and nature of faults, shear zones, joints, structural unconformities, etc

I - Geomechanical properties of material to be removed, shear strength, tensile strength, durability.

The above parameters were obtained in order to allow an assessment of the

following:

I - Need for and extent of dewatering of pit due to presence of groundwater. Effect of dewatering on source aquifers

I - Stability of the highwall, particularly in zones where overburden is weak. Need for flattening or benching highwall

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- Lowwall and spoilpile stability. The aim here was to assess whether such problems are likely to occur, rather than to investigate them in the detail

I necessary to provide solutions

- Characteristics of material with respect to drilling, blasting, excavation.

As mentioned earlier, the highwall stability aspects of our study were covered

in our first report. This report covers the other aspects noted above.

It should be pointed out that the geotechnical study was aimed at providing

I input into the detailed pit planning study. Its primary objectives were to

highlight potential problem areas of geotechnical significance; e.g. ground-

I water control; weak mudstone layers immediately beneath major seams which

could present floor heave problems or spoilpile stability problems; weak or

I badly jointed overburden materials which could present highwall stability

problems, etc.

It was not practical or advisable to attempt detailed analyses of these

problem areas or to develop comprehensive solutions at this feasibility stage

of the development, where a decision has yet to be made on whether the

development will go ahead and if so exactly which areas would be developed

and in what sequence. We would develop basic recommendations only. More

detailed recommendations could only be made once the mine plan were more

fully developed.

2.2 Method of Geotechnical Study

An extensive coal exploration drilling program was carried out by R W Miller

I & Co from February to November 1977. This program consisted of the coring

of approximately 95 holes, the locations of which are shown on Figure 1.

I The depths of the holes varied. The majority of the holes in the eastern

zone were taken to the base of the Piercefold seam (depth 150-200 m). Selected

I holes were taken deeper for correlation of the upper coal measures with

deeper reference strata.

For extraction of geotechnical data, we selected six holes in the eastern zone

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and three in the western zone as being representative of each area. The holes

selected were:

Eastern zone: BB24 X24

BB28 X28

BB32 X32

Western zone: L24

L32

028

For each hole we prepared an engineering geological log, from the surface to

below the seam(s) to be mined, generally to a depth of about 200 m for the

eastern zone and to a depth of about 100 m in the western zone. The logs for

holes BB24 to X32 were included in the first report. The logs for holes L24,

L32 and 028 are included as Figures A2 to A14 in the Appendix of this report.

The logs were prepared from field logging performed by our field engineers,

who carried out the following tasks:

- Noted all defects, including joints, shear zones, bedding partings, clayey

bands

- Noted the extent of surface weathering

- performed point load strength tests at regular spacing

- Recovered selected samples for laboratory testing.

In addition, surface weathering data were obtained from other selected holes

in the eastern zone and some samples were recovered from other holes for

laboratory testing.

Slotted PC standpipes were installed in the following holes: AA31, BB24,

I BB28, BB32, L24, L32, X24, X28, X32 and Z28 to allow long-term monitoring

of groundwater levels.

I The following laboratory tests were performed on selected samples to obtain

I data on the rock properties:

- Uniaxial (unconfined) compression tests to evaluate the strength of intact

Irock

- Direct shear tests ("Hoek" shear box tests) to measure the shear strength

of discontinuitieS, including bedding planes and joints

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- Direct shear tests (soil shear box tests) to measure the shear strength of weathered, soil-like material

- Moisture content and density tests

I - Slake durability tests.

I The results of the laboratory testing are included in the Appendix.

1 3.0 MINE PLAN

I The details of the mine plan for the eastern zone currently available have

been extracted from a report presented to us by Kinnaird Hill de Rohan &

Young, titled "Preliminary Study for Coal Mining Operations at Mt Thorley"

I dated October 1977. The report indicates that the optimum mine plan would be

a shovel and truck operation using up to four stripping shovels with a

I possibility of using a dragline to replace the bottom truck/shovel spread.

Figure 2 shows a schematic view of the pit after four years of operation.

I This plan is based on an initial rate of production of 1.5 million tonnes of

raw coal per year increasing to 3 million tonnes per year after two years.

I After six years, the rate of production will be increased to the maximum of

4 million tonnes per year.

Figures 3 and 4 show typical cross sections through the pit. As shown, the

pit will not have a lowwall in the usual sense; the Piercefield seam

I outcrops adjacent to the "Mt Thorley Fault" where it has been dragged upward

so that the dip of the seam near crop is about 50°. Essentially, the floor

I of the seam will form the lowwall; it will be benched to produce a similar

profile geometry to the highwall. Kinnaird Hill have indicated that they are

I considering an overall slope of 360 to 45

0 for the lowwall.

I No details of the mine plan for the weatern zone are available as yet.

Basically, the Whybrow seam would be mined in this zone, involving mining to

I depths up to 100 m. It is assumed that similar highwall, lowwall and soil

pile geometries as are planned for the eastern zone would apply.

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I 4.0 SITE CONDITIONS

1 4.1 Geology

The strata dip generally at between 1:10 and 1:20 in a direction about 30°

I south of west. However, the dip increases sharply in the eastern part of the

site, in the vicinity of the "Mt Thorley Fault", where the dip increases to

up to about 500. East of the fault, the marine strata of the Maitland Group

crop. As a result, the fault structure establishes the eastern limit for

I coal potential in the lease area. No other significant faulting has been

indicated by drilling in the eastern zone.

4.2 Hydrology

To our knowledge, there have been no hydrologic studies performed in the

area. The only available data at present are groundwater measurements from

I the seven boreholes in which standpipes have been installed.

I Groundwater levels have been monitored in these borings since July 1977 and

the readings are tabulated on Figure 5 . Results of this monitoring show

I that groundwater levels stand at between 7 m and 32 m below the ground

surface.

5.0 HIGHWALL STABILITY - WESTERN ZONE

The discussion on highwall stability presented: in the first report applies

equally to the highwalls in the western zone. The logs of the holes in this

I zone which were logged by Dames & Moore (L24, L32, 028) are included in the

Appendix.

I In general, the overburden conditions revealed by the logs are similar to those

I found in the eastern zone. The comments and recommendations included in our

first report can be taken as being applicable to the western zone.

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6.0 L0WALL STABILITY

6.1 General

The factors which affect the stability of the lowwall are the same as those

affecting the stability of the highwall, namely:

- strength of rock mass

- orientation and character of discontinuities

- groundwater conditions

- seismic and blasting effects

- surface loads

- mining procedures.

I The comments made in the report on highwall stability apply equally to the

stability of the lowwall, with the exception of orientation and character of

I discontinuities. Consequently, the comments on the other factors will not

be repeated here.

Kinnaird Hill have indicated that they are planning the lowwall geometries as

shown on Figure 3 with an overall slope of about 360. They have indicated

however, that they are considering steepening the overall slope of the

lowwall to 450 .

6.2 Lowwall Stability -Eastern Zone

In the eastern zone, the most significant geotechnical feature affecting the

stability of the lowwall is the relative steeb dip of the strata in the

vicinity of the "Mt. Thorley Fault".

In flat bedded strata, the stability of the rock face is not significantly

affected by the dip of the strata - it is more dependent upon frequency

and nature of joints, sheared zones, rock strength, etc (refer to report

on highwall stability). However, where the strata are not flat-bedded, as

is the case in the vicinity of the lowwall, the dip of the bedding must

be taken into account in designing the geometry of the rock face.

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From the point of view of overall stability of the lowwalls, they should be

I formed so that their overall slope should be no steeper than the dip of the

strata, to preclude the possibility of a sliding failure along bedding. In the

I case of the Mt. Thorley strata, strength along bedding is generally high. However,

occasional weak seams occur which could present overall stability problems if

the bedding "daylighted" out of the lowwall face.

We understand that the mine planners, Kinniard Hill, are contemplating overall

I lowwall slopes of 360. As shown on Figure 3*, this is flatter than the dip of

the strata for lines 24 and 28 and slightly steeper for line 32. Further south

I of line 32 the strata dip is slightly flatter than the slope of the lowwall.

This increase in dip of the strata to the south is due to the fact that the

I crop of the seam becomes further distant from, and thus less affected by, the

fault to the south. However, where the dip of the seam is flatter than the

I slope of the lowwall in the upper portion of the seam, the lowwall slope will

necessarily be dictated by the slope of the seam. It is assumed that, while

the upper portions of the lowwall will be formed at 360 or the slope of the seam,

I which ever is less, the lower portion would follow the dip of the seam and

flatten out accordingly.

If the lowwalls are formed in this way, the overall slope of the lowwall will

I be no steeper than the dip of the strata and overall stability would be adequate.

However, the possibility of some bench failures would still eXist. This is due

Ito the fact that individual bench faces, formed at about 700, are much steeper

than the dip of the strata. As a result sliding failures of benches along bedding

which "daylights" in the bench face could occur. Bench failures can occur during

I blasting or later during the lifetime of the pit, as the quality of the rock

deteriorates. Failures of individual benches could only be eliminated by flatten-

I ing bench faces to an angle equal to or flatter than the bedding dip.

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* It is noted that the plane of each of the lines 24, 28 and 32 is not

perpendicular to the cut. The true dip of the strata in relation to the

lowwall is slightly greater than shown on Figure 3.

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I 6.3

Lowwall Stability - Western Zone

The above comments refer to the lowwall in the eastern zone. We have not

yet been provided with details of the mine plan for the western zone.

However, since the Whybrow seam is not influenced by a fault as is the

Piercefield, the height of the lowwall will be significantly less than in

the eastern zone. In addition, the dip of the strata out of the highwall

will be only on the order of 6 0.

As a result, significant lowwall staolty

problems are less likely to occur in the western zone than in the eastern

zone.

7.0 SPOIL PILE STABILITY

The primary factors influencing the stability of the spoil piles will be:

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nature of spoil

- geometry of spoil pile

- nature and slope of spoil pile floor

- water conditions.

I 7.1 Nature of Spoil

I The spoil will consist primarily of competent sandstone and siltstone rock

fragments, from sand to boulder size but primarily of cobble size with minor

conglomerate and claystone.

We have performed slake durability tests to evaluate the extent to which the

I overburden rocks will be effected by exposure to the elements and to handling.

The test results are included in the Appendix. The tests indicate that the

I durability of the spoil will be high and that the majority of the rock will

not significantly break down during the life of the mine. The exceptions to

this general rule are the near-surface weathered rocks and the occasional

band of carbonaceous siltstone found adjacent to the coal seams. Since these

I rock types represent such a small proportion of the total overburden, their

presence should not be significant.

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7.2 Geometry of Spoil Piles

7.2.1 Spoil in Open-Cut

It is our understanding that the spoil will initially be dumped in permanent

spoil disposal areas to the east of the "Mt Thorley Fault" on non-coal bearing

land. Once the pit has advanced sufficiently far westward to provide enough

space, spoil will then be dumped directly into the pit. The face of the

spoil will then advance with the highwall.

Kinnaird Hill, the mine planners, advise that they anticipate that the final

level of the top of the spoil pile will be 45 m above the existing surface

level. The spoil will be benched, with maximum bench heights of 45m and

bench widths of 37 m. The benches would be located at the same levels as

selected highwall benches. The geometry of the spoil pile face resulting

from such requirements would be as shown on Figure 4, with an overall slope

of about 26°. This is based on the assumption that the dumped spoil will lie

at an angle of repose of 370 - 380 , which is typically the case in rocks of this

type.

7.2.2 Spoil in Permanent Spoil Piles

The geometry of proposed permanent overburden spoil piles is detailed in the

Environmental Standards Report*. This report shows the spoil piles to have a

surface slope of 1:10 (vertical:horizontal) with a benched perimeter slope of

about 220. They will be constructed on terrain with maximum slopes of about

1:20. Based on this geometry, and the compaction to be employed, we see no

reason to anticipate stability problems with these spoil piles.

I * "Report on The Environmental Standards and Alternatives for the Mount Thorley

Colliery", by James B. Croft & Asslociates, August, 1977.

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7.3 Nature and Slope of Spoil Pile Floor

The nature of and/or slope of the floor of the pit is often the major factor

leading to spoil pile instability. Often, the material immediately underlying

the coal seam. i.e. the material which forms the floor of the pit after the

coal is removed, is weak and/or becomes weaker on exposure to air and/or water.

Claystone bands of relatively low strength were encountered beneath the

Piercefield seam in some of the boreholes. However, in the majority of the

holes, the coal floor material is competent. Figure 5 shows a summary of the

material logged beneath the Piercefield seam in representative boreholes.

Based on this data, and on our knowledge of the geology of the area, we do

not consider such seams to be continuous beneath the Piercefield seam (or

the Glen Munro/Woodlands Hill or Mt Arthur seams).

Slake durability tests performed on samples of seam floor material show that

it does not break down significantly under exposure to air and water

indicating that, in general, the pit floor will be competent. It should

be ntoed however, that some of the core from beneath the Piercefield seam

was very weak (claystone) and was not suitable for slake durability

(or strength) testing. (See Figure 5).

The base of the spoil pile will generally dip at an angle of 30-6

0 toward the

highwall, the latter being the dip of the Piercefield seam. This degree of

dip applies only in the area to the west of the "Mt. morley Fault" and a;ay

from its influence limuediately to the west of the fault, however, the dID

of the seam increases up to 500. -

Generally, the steep sections of the seam will form the lowwall of the pit.

However, there will be a zone of transition between the base of the lc;c;all

and the evenly sloping pit floor. The slope of this zone will vary be.ween 0 0

say, 6 and 15

It will be important to ensure that benching of the lowwall extends through

this zone of transition slope, otherwise a major source of potential

instability could be created.

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I 7.4 Water Conditions

I The presence of excessive water in spoil piles can seriously affect their

stability. This can occur when the nature of the rock comprising the spoil

is such that .t weakens when exposed to air and water (eg. clay shales)

and/or the water has a similar effect on the competence of the floor material.

Based on the evidence from the slake durability tests (results shown on

Figures A15, A16 in the Appendix), and as mentioned previously, the over-

burden rocks at Mt. Thorley will generally be highly resistant to weakening

on exposure to water.

Another way in which water can affect spoil pile stability is by saturating

the spoil, with the resulting buoyancy effect reducing the effective

frictional strength. To prevent this occurring, care should be taken at all

times to maintain the geometry of the spoil piles in such a way that rain

water ponding, which leads to seepage into the spoil, is avoided. This

can be done by grading the benches so that surface water is drained off

into the pit. If this procedure is not sufficiently effective, it may be

necessary to consider lining the drainage ditches to maximise run-off.

8.0 PIT FLOOR STABILITY

Pit floor stability problems can occur in surface mines, usually being

manifested by floor heave. This uplifting of the floor is usually the result

of the presence of a layer of relatively weak, fine-grained material beneath

the coal seam, which forms the floor of the pit. This material is of ter

I further weakened by exposure to air and water and, being relatively impermeable,

can be subjected to high groundwater uplift forces. Either of these factors,

I or usually a combination of the two, can result in buckling of the floor,

presenting operational problems.

I As mentioned previously, at Mt. Thorley, the material underlying the Piercefield

seam are generally competent and does not significantly break down on exposure.

1 Also, the permeability of the floor material would not be significantly lower

than that of the deeper rocks, so that major hydrostatic uplift forces

should not be generated.

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9.0 GROUNDWATER CONDITIONS

9.1 General

The groundwater conditions at Mt. Thorley have been investigated by monitoring

groundwater levels in standpipe piezometers installed in selected boreholes,

and by performing pump-out tests in selected holes. The details of this

program are included in the Appendix.

Examination of the core and borehole logs and experience with coal measures

I rocks indicate that the coal seams form the primary groundwater aquifer

layers; i.e. the permeability of the coal is much higher than that of the

enclosing rocks. In such a case, where a particular layer forms a "confined

I aquifer", the water in the layer can be at artesian pressure. This depends

very much on the source of water "feeding" the aquifer and the relative

I permeabilities of the aquifer and the enclosing rocks.

Our investigations indicate that the water in the coal seams is not under

artesian pressure but under normal hydrostatic pressure dictated by the

I level of the standing water table. This is illustrated, for instance, by

the fact that in drilling observation wells adjacent to existing boreholes

I which extended through the main coal seams, the groundwater table was

encountered at about the same level as the water level in the borehole

through the seams.

9.2 Estimated Groundwater Flows into Pit

The pump-out test results in holes BB28, BB30 and BB32 are shown in the

Appendix. Our estimated groundwater inflow rates for varying pit dimensions

and at varying times after opening-up of the pit are shown on Figures A20, A21.

Accurate prediction of pit inflow rates from a limited program of pumP-cut

testing is difficult. The prime object of the field program was to provide

an indication of the order of magnitude of flow rates and the test results

allow such a prediction. We estimate that, for a pit of length 1500m and

base width of 30m, an average groundwater inflow rate of 300,000 litres per

day can be expected for the first several years of operation.

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This represents the combined flow from the Glen Munro/Woodlands Hill and

Piercefield seams. The test data indicates that the transmissibility, or

groundwater out-flow capacity, of the Piercefield seam is proportionally

larger than the Glen Munro/WoodlandS Hill seam by its seam thickness as it is

assumedthat the permeability of the coal in each of the two seams is the same.

It is thus concluded that the transmissibility of the lower seam is twice that

of the upper seam.

The rate of flow of water out of the seam will drop off as the "driving"

head is reduced. This is due to the fact that, being a confined aquifer,

with relatively impermeable enclosing rocks and no significant source of

recharge, the seam will eventually be drained of its contained water. It

is not possible to make an accurate estimate of the time required for each

seam to effectively drain, based on the presently available data, but we

would estimate that this would occur over a period of some years.

10.0 OVERBURDEN EXCAVATION CHARACTERISTICS

The most efficient means of removing overburden depends on the following

factors:

- strength of material fabric

- occurrence of planes of weakness.

As has been mentioned previously, the (fresh) rocks at Mt. Thorley are of

relatively high strength with relatively low occurrence of bedding partings

and weak bands. while the jointing pattern has not been established from

core logging, the majority of joints are likely to be vertical to sub-vertical

and generally spaced in the order of 0.51n to 2m.

The fresh rocks will require drilling and blasting to allow shovel excavation.

The extent of surface weathering, which reduces the rock strength so that it

can be removed without blasting, is shown on the borehole logs as well as on

Figures 6, 7 and 8. While the performance of trial excavations is the most

reliable means of determining the most efficient means of overburden removal,

the strength and fracture spacing data shown on the borehole logs allows a

prediction of the excavation characteristics, using published procedUreS*.

* Ref: J.A. Franklin, E. Broch & G. Walton "Logging the Mechanical Character

I of Rock", Trans. Inst. of Mm. & Metall., London, Vol 8, January, 1971.

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As shown, it is predicted that the overburden could be removed using scrapers

I only (or pushed by dozers) from the surface to a depth of about 5m, with some

bands requiring ripping, and it could be removed using scrapers after dozer

ripping from about 5m to about 10 to 15m. Below 10 to 15m, the rocks will

I require blasting.

While the data shown on Figures 6, 7 and 8 may not in fact relate closely to

actual excavation practice, i.e. the level at which the rocks require ripping

I or blasting may be higher or lower than shown, Figures 6, 7 and 8 and the

logs do allow an assessment of how the excavation characteristics might vary

I across the site. In general, there appears to be no trend of variation in

thickness of weathered material in any specific direction, i.e. while there

may be occasional areas where the degree of surface weathering is markedly

I different from the general condition, on the whole, the extent of surface

weathering is reasonably consistent over the site.

I The fact that the initial small scale mining operation will be performed under

I contract, where it will be the contractor's task to experiment with various

combinations of excavation equipment to produce the most efficient method

I of overburden removal in each weathering horizon, will be an advantage.

This will allow R W Miller & Co to use this experience in combination with

I the data presented herein, to produce the most efficient means of overburden

removal.

11.0 CONCLUSIONS AND RECOMMENDATIONS

11.1 Highwall Stability - Western Zone

The likelihood of stability problems with highwalls in the western zone

should be less than for those in the eastern zone, assuming similar slope

geometry. The geotechnical properties of the strata are similar but the

maximum highwall heights will be significantly lower. At this stage, however,

we would recommend adoption of the same highwall geometry for the western

zone as for the eastern zone. (Refer to Dames & Moore report on Highwall

Stability.)

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11.2 Lowwall Stability - Eastern Zone

It is understood that maximum overall slopes of 360 are planned for the lowwall,

I with a benched profile as shown on Figure 3. It is also assumed, however,

that in the lower portions of the lowwall, where the dip of the seam flattens,

I the slope of the lowwall would be reduced accordingly to conform with the

slope of the seam. The dip of the seam increases from about 340

in the south

to about 510

in the north.

I Due to the general competence of the overburden rocks, we feel that a lowwall

formed at a maximum overall slope of 360 in the upper portions and flattening

nearer to base where the seam flattens, with a benched profile as in Figure 3,

would have good overall stability.

The possibility exists for isolated failures of individual benches where

I the dip of the strata is high and occasional weak bands occur. This is more

likely to occur in the northern part of the site where the dip of the strata

I is greatest. However, most such failures should occur upon blasting and

excavation. We consider the possibility of extensive bench failures in service

I to be low. Should, however, it be considered necessary to completely

eliminate the possibility of bench failures, consideration could be given

I to stacking benches excavated at the bedding angle or lower, say up to three

feet high, so that undercutting of bedding is avoided.

The procedure which would result in minimum excavation of material beneath

I the seam would be to form the lowwall at the same overall slope as that of

the seam, over the full height of the lowwall. This would mean a steepening

of the slope beyond 360 for the upper portion of the lowwall in the northern

I part of the site, to a maximum of about 500. on the basis of the data

presently available, it is not possible to assess the effect such steepening

I would have on overall stability of the lowwall.

I We recommend that for present planning purposes, the overall slope of the

lowwall be designed for a maximum slope of 360. Should the economic

I advantage of steepening the lowwall in the northern part of the site be

considered to warrant further investigation, this could be done during the

detailed design stage.

Li

- 17 -

Li

11.3 Lowwall Stability - Western Zone

Due to the absence of faulting in the vicinity of the lowwall in the western

I zone, design of the lowwall does not warrant the detailed consideration

required in the eastern zone. For preliminary design purposes, we would

I recommend adoption of a benched profile of overall slope 360 as shown on

Figure 3.

1 11.4 Spoil Stability

I Spoilpiles developed in accordance with the geometry shown on Figure 4 should

experience no major stability problems. Failures could occur in areas where

I the material forming.the floor of the pit is weak. Care should be taken to

identify such areas upon exposure by coal removal, and remedial measures taken.

I Such measures could consist of the following: Where the weak zones are

relatively isolated, the weak material should be removed and disposed of

with the overburden. Where the weak areas are extensive such that their

I removal would be too costly an exercise, trenches could be excavated through

to more compenent material parallel to the toe of the spoil. This would

I effectively "key" to toe of the spoil into the floor of the pit. Typically,

these trenches would be about 25m wide at lOOm spacing.

Continuous grading of the upper surface of the spoilpiles should be performed

toavoid ponding of rain water and thereby minimising the possibility of

saturation of the spoil with subsequent reduction in stability.

11.5 Groundwater Inf lows

I As mentioned in section 9.2, our field investigation program was aimed at

estimating the order of magnitude of groundwater inflows into the pit, rather

I than attempting detailed flow predictions. We estimate that during the first

two to three years of operation of the pit, flow from both seams of the order

of 300,000 litres per day can be expected for pit dimensions of 1500m long by

30m wide at the base. The flow, from the Glen Munro/Woodlands Hill seam should

constitute about one third of this total flow.

I L I

-18-

I

We suggest that the rate of groundwater flow into the pit during the initial

I contract mining operation be monitored to allow a more accurate prediction of

longer term flow rates. Based on the limited data available to date, we would

I estimate that the rate of flow to be expected from the Piercefield seam would

that in the Glen Munro/Woodlands Hill Seam. be about 200 encountered

11.6 Overburden Excavation

I Our investigation indicates that generally the overburden from the surface to a

depth of about 5m could be removed using scrapers and dozers, with some bands

I requiring ripping; the rock between 5m and 10 to 15m below the surface should

require extensive ripping while the rocks below lOin to 15m will require

blasting.

Again, the initial contractmining operation should be closely monitored and

I this data, along with the strength and fracture frequency data shown on the

geotechnical logs, be used to predict excavation characteristics in other parts

I of the site.

I I I I I I I I I I

- 19 -

LIST OF FIGURES

Figure No

1 Site Plan

2 Pit Schematic

3 Sections AA t , BB 1 , CC' - Lines of Boreholes 24, 28, 32

Showing Approximate Lowwall Profiles

4 Typical Highwall and Spoilpile Geometry

5 Properties of Rock Underlying Piercefield Seam

6 Groundwater Levels and Rainfall Data

7,8,9,10 stratigraphic Sections - Lines 24, 28, 32

S :

/

( (Li (

17- 052?

300 3b0000

WESTERN ZONE 30000

IE

0000

I I I I I I I I I I I I I I I I I I I I

1388150

1386000

10 Z25 8025

C) 025

1307000

8

c onFFU o

028 C20

V

A20 7C20

I /7

/

000300 8302 C30 DD

20

31 flO OSHO 1386000

:f 0633

0 0

00002 832 CC32 0

000 L

033 0033

I 0 I I - ho85300

39000 L 330000 310950

EASTERN ZONE

REF., R.W MILLER DRG. - PLAN 2 SITE PLAN DATED 17/ 10/77

SCALE a oon. 0 200 400 600 800 1000m

FIGURE I

LEGEND

WAMBO— Inferred Outcrop of Seam

$8828 Location of borehole

50m contour

I I I PIT SCHEMATIC

D1ES B MaOnrz

FIGURE 2

REF REPORT; "Preliminary Study for Cool Mining Operations at Mt Thorley"

by Kinnoird Hill de Rohan a Young Pty Ltd. doted Oct, 1977, Fig. I

I I I I I I I I I I I I I I I I I

01-i 12 OHi2M 01-1121 0H12i

- SURFACE - -

'- BENCHED LOW WALL OVERALL SLOPE 34° iO

70° -O

_b I_ --20

-40

-50

-60

OH 20H OH 20M OH2OK OH2OL

0

70

50

4°

30

20

F- 0

L

-20

-30

-50

--60

--70

-80

L 9

OH4G OH:4H 0H41 OH4J

BENCHED LOW WALL OVERALL SLOPE 34°

I I I I I I I I I I I I I I I I I I I I

R(.

60

50-

40

30-

20

iO 1 0-1 OH

20 H

° H - 40

-50

60

R.L 80,

70

60

50

40 -i

30 H 20 -I

0 -

oH

-10

-20

-301

-40

50 H

-60

-7° H

-80

- 90 -

R.L. 70

60

50 -

401

30 -

20

iO-

oH - 10 -

- 20-

- 30-

- 40

- 50 -

- 60-

- 70-

- 80-

- 90-

BB24

plER0 SEAM

INN - SECTION A-

BB8 CC28

SECTION B -B' LINE 28

BB32 CC32

P1

SECTION CC* LINE 32

NOTE

The lines of boreholes ore not per pendiculor to the strike of the strata As a result the dips of the seams shown are apparent dips and the slope of the low wall as shown is less than its maximum slope The true dip of the seams along lines 24,28 and 32 are 51°.42°and 340 respectively and the irue overall low wall slope is 36°.

NOTE See Fig. I for locations of sect ions

R.L. 70

SCALE I 1000

40

60

50

F I_30

F 20

tO

CROSS - SECTIONS h20 AABBCC1 — LINES -30 OF BOREHOLES 24,

Ho 28,32, SHOWING ° APPROXIMATE

b60 LOW WALL PROFILES 70

B --90 t(lIP

38° OVERALL SLOPE 360

HIGH WALL

_-.- R --OVERALL SLOPE 26 0

TYPICAL HIGHWALL AND SPOILPILE GEOMETRY

Kit

SCALE: 1:2000 DSBP.00flE

FIGURE 4

I I I I I I I I I I I I I I I I I I I I

PROPERTIES OF ROCK UNDERLYING PIERCEFIELD SEAN

Borehole Depth Rock Type *Estirnated Slake Compressive Durability

No (m) Strength Classification Classification

X26 116.85 Interlaminated fine low-medium sandstone and siltstone with carbonaceous bands

Z24 137.84 Carbonaceous Mudstone low medium high

Z28 180.55 Interlaminated sand- stone and siltstone medium medium high

Z32 168.32 Interlaminated sand- stone and siltstone medium-high medium

AA28 151.86 Interlaminated sand- stone and siltstone medium

AA32 163.95 Interlaminated fine sandstone and siltstone medium

BB24 124.35 Claystone extremely low low**

- very low

BB27 149.79 Interlaminated sand- stone and siltstone medium

BB28 160.14 Interlaminated sand- stone and siltstone medium-high high

BB29 162.35 Fine to medium sand- stone with siltstone medium

BB30 158.55 Interlaminated sand- stone and siltstone medium

B332 148.57 Claystone very low low**

CC32 129.02 Sandstone low-medium

* Point Load Strength tests on these samples at natural moisture content not possible since core removed from site with coal, core for coal analysis.

** Core samples too weak for sensible testing - low slake durability classificatio3 based on weak condition of core.

Figure 5

TABLE OF GROUNDWATER LEVELS

Depth from Surface to Groundwater Table (in)

Borehole Date of Measurement (All 1977)

No. 6 July 7 July 8 July 15 July 10 Aug 2 Nov 21 Dec 2i jiec

AA31 7.0 - - 8.0 9.7 9.8 -

- 15.2 - - 14.5 13.3 13.4 - BB24

BB28 14.6 - - 13.2 15.3 14.8 - - 4.9

BB32 - - - - - - - 22.0 21.4 21.6 -

X24 - - - X28 16.1 - - 31.5 31.0 30.9 31.0 -

X32 18.5 - - - 18.0 17.8 17.9 -

- - 18.5 - 16.0 14.6 15.2 - Z28 - 12.0 L24 - - - - - - - GWL@ L32 - - - - - - Surf ace*

flowing out of hole at rate of 100 c.c per minute. * Water

TABLE OF RAINFALL DATA*

Monthly Totals (mm) for 1977

June July August September October November

15 4 17 48 8 16

** Rainfall data for Jerrys Plains from the Weather Bureau

Figure 6

SOIL & SUBSOIL.

I uu_j A/I.A I

COAL. AGGLOMERATE

COAL & BANDS INTERCALATED.

CARBONACEOUS SHALE.

SHALE - NOT CARBONACEOUS.

COAL TYPE

SHALE & COAL EANDS. WHEN RECORDED

DULL

ULL BANDE

SHALE - CARBONACEOUS N PAPJ. ULL & RIGHT

LBRIGHT BANDED

SHALE & SANDSTONE.

.. . : -:1 GRIT & PEBBLES SANDSTONE TYPE

' f FINE :?4 1FINE TO

0 CONGLOMERATE. MEDIUM

e • MED1UM

• MEDIUM TO COARSE

CLAYSTONE & MUDSTONE. COARSE

CLAYSHALE. Ii/l SANDSTONE & SHALE

_- -=

:--1 SILTSTONE. SANDSTONE & COAL BAND

A A A A] E1 TUFEF=AA-

CLAYSTONE-?TUFFACEOUS

A AA A A

A—

B Note for mixed lithologies e.g. fine sandstone

AA] sitty in part a tIne boundIng the sandston symbot indicates fine sandstone is domincnt

IGNEOUS ROCKS.- otherwi5e fine sandstone overprints the DOLERITE. sittstone but no bounding tine is drc.vn.

sndstone CHERT

or°st

sittstore

- - . sandstone

) ' . COAL CINDERED. No mckIhc Lusr€ & Cok-Iik. .: I Lost SOO/o ktrs'vblatiSe of ,(: Cont,nt i stIi a

CommercaI Pot.gtt,aI as a futt

COAL CINDERED. Ash-Iskt. no comorcot Potvtial as a FtI.

MATERIAL FROM 0.0 TO 4.5m : EXCAVATABLE BY SCRAPERS 4.5m

MATERIAL FROM 4.5 TO 9.Om EXCAVATABLE BY RIPPING 9. Om

I I I I I I I I I I I I I I I I I I

_jpm GROUND WATER TA3 L E

DEGREES OF

EXCAVATABILITY

(DEPTHS)

I

LEGEND- GRAPHIC LOGS

I REF.: JCB PLAN No. EC 507A FIGURE 7

70.

X2L

)/,

I

WEST

EAST R DD

lOOm

Z2

4424

I,

os,, ,.10

370,, 660,,

605,,

os,,

7,.0,, 360,,

660,,

-

li

50.

NOTE SEE FIGURE 7 FOR LEGEND

REF JCB PLAN No. Al-C206 doted 24.3.77.

,6,7'N7A. '. Aol 6N.,I'Fof vIA' A OCAIF IN 6.16166

100 50 0 100 10 5 0 10

STRATIGRIPHIC SECTIONS LINE 24

DAMES & MOOR* FIGURE 8

WEST EAST R DD

Z2t

80n, -1

I AA 28

9H 28 iE4 : -1--

SO

4.=

8.

7001

6001 •

TOrn , :1

400,

30nr 49.460rn

2010

On, -

.14 IOO. - 7lrrn

I.. - o.

J. 91615., 91 91-

- 101 45Cm - 20,1

III

104 030,, - 1(15 50(1 ISO 405,,

SIdo.,Ie

SOrn

60.

! it 11 ,, .'. 151 550m I5t. 27511

-801,1

i

- -

- 90 00

UDH1 STRATIGRAPHIC -10001 DDH - SECTIONS

LINE 28 NOTE SEE FIGURE 7 FOR LEGEND REF JCB PLAN No. AI-C206 doted 7.6.77 HOLE ' TERMINATED - 1100, AT 317.415m @9

00,1005141 SCAlE IN METRES

100 50 0 100

. i,I4( 0, A, ,', M'WI

10 5 0 10 . - O•B B moomm FIGURE 9

I I I LI I LI I P H

H

P

I I LI I I I I I I I

A32

IOn

S

-2On

-3O

PW

AOn,

NOTE SEE FIGURE 7 FOR LEGEND

REF .JCB PLAN No. At-C206 dated 17.3.77

100 50 0 100

I I I I I I I I I I I I I I I I I I I I 10 5 0 10

WEST R

Z 32

EAST

DD

R.L. 65 460ns.

ACEREDUCED EL 62.57559 L OF 6832 SURFACE REDUCED ISITIONED TO

J LEVEL OF CC 32 55 460n,.

•- 1

POI.IoD TO 5 62.575m.

7?11P90

STRTIGRAPHIC SECTIONS LINE 32

DAMB & MOORE FIGURE 10

I -20-

I APPENDIX

FIELD INVESTIGATION AND LABORATORY TESTING

For details of the field exploration and laboratory testing performed are as

covered in the appendix of our report "Geotechnical Investigation, Highwall

Stability, Proposed Surface Coal Mine, Mt. Thorley, N.S.W.", submitted on

14 November, 1977.

The items covered in that appendix are as follows:

Field Exploration: Core logging

Installation of Standpipes

Point Load Testing

Laboratory Testing: Moisture and Density Determinations

tjniaxial Compressive Strength Testing

Direct Shear Strength Tests

Direct Shear Tests on Joints

This data will not be repeated in this report; this Appendix, however r, presents

the details of the borehole pump-out test program.

Field Work: Borehole Pump-out Tests

Pump-out tests were performed in boreholes BB28, BB30 and BB32 to determine the

transmissivities of the Glen Munro/Woodland Hills seam and the Piercefield seam,

which allowed an estimation of the rate of flow of groundwater into the pit.

Borehole BB32 was tested on September 23, BB30 on November 4, and BB28 on

November 9, 1977. Pump-out test results from BB30 and BB32 provided estimates

of pit inflow rates from the Glen Munro/WoodlandS Hill seam and test results from

BB28 provided estimates of pit inf low rates from both the Glen Munro/WoodlandS

Hill and piercefield seams.

I The transmissivity (T) of a water bearing formation is dependent on its thick-

ness and its permeability. In computing T from the pumping tests, it is assumed

that the Glen Munro/Woodlands Hill and Piercefield seams have a reasonably

I uniform permeability and that the enclosing rock layers are relatively impermeable.

I

- 21 -

The best way to determine T is from water level recovery data following pump

shut-off after a period of eight hours during which a stable pumping rate has

been maintained.

The time-drawndown measurements during the pumping period and the time-recovery

measurements during the recovery period provide two distinct sets of information

for a test from which the residual drawndown curve is plotted and used to

determine the value of transmissivity (gallons per day per foot) for the seam

(or seams) in the particular borehole tested.

Method of Testing

In borehole BB32, a Prosser submersible 71-2 HP electrical turbine pump (rated

at 120 gallons/mm) with 75mm diameter PVC evacuation pipe were used. In

boreholes BB28 and BB30, a Grundfos electricsubmersible pump, model SP10/18,

5 HP, 3 phase motor was used instead. In both cases, a 20kVA, 3 phase generator

was used to drive the pumps.

In each test, the pump was lowered down the 280mm dia. borehole and suspended

with a cable at the required levels of depth below the top of each hole for the

entire test. PVC standpipes, 43mm in diameter and perforated at the bottom

3 metres of its length were installed in each pump hole down to the level of

the pump. An electrical water level measuring probe was used to measure the

water levels in these standpipes during the drawdown and recovery stages of

the tests. The purpose of operating the electrical water level measuring

probesin the standpipes was to eliminate possible misreading of the probe due

to cascading water from above.

In boreholes BB28 and BB32, no observation wells were available. In borehole

B330, 2 observation wells (BB30/1 and BB30/2) were available and their positions

Iwith respect to the pump hole BB30 were as shown below.

Pump Hole

Observation Wells N

BB30 BB30/2 BB30/1 ____

4.6rn

12.2m

- 22 -

PVC standpipes were installed in these observation wells as in the case for

the pump holes. The water level recovery data from these wells fully reflects

the hydraulic characteristics of the coal seams.

During the pumping period, pumping was maintained at a constant rate by measuring

the rate of water discharged from the outlet. The outflow was controlled

by regulating the outlet control valve to obtain the required pumping rate.

On commencement of each test, time-drawdown measurements were recorded for the

pumping period, which averaged eight hours for each of the three pump tests.

When the pump was switched off, time-recovery measurements were recorded. The

actual recovery in the water level - the distance that the water rises after

pumping ceases - was expressed with reference to the pumping water level. These

recordings yielded the residual drawdown curves (as shown in Figures A15-A17),

required for the determination of T, the transmissivity of the coal seam.

Test Results

Test 1

Borehole: BB32 Date: 23 September 1977

Depth to bottom of borehole = 23.5m

Depth to top of Glen Munro/Woodlands Hill seam = 18.Om

Thickness of seam = 8m

Static groundwater level at 4.Om

Pumping level at 22m

Pumping period = 3½ hours

Average pumping rate = 9 gallons per minute

Transmissivity, T = 43.9 gallons per day per foot (refer residual drawdown curve,

Figure A15).

Test 2

Borehole: BB30 Date: 4 November 1977

Depth to bottom of borehole = 35.5m

Depth to top of Glen Munro/Woodlands Hill seam = 26.47m

Thickness of seam = 7.93m

Static groundwater level at 1l.85m

Pumping level at 26.0m

I -23-

I Test 2 (continUed)

Average pumping rate = 8.95 gallons per minute

IPumping period = 73a hours TransmiSSiVitY, T = 70.6 gallons per day per foot (refer residual drawdown

I

curve Figure A16a).

Observation Well: BB30/1

I Location: 12.2m to east of BB30

Depth of bottom of borehole = 38.5m

Depth to top of Glen Munro/WoOdlands Hill seam = 26.Om

IThickness of seam = 8.5m

Static groundwater level at 11.29m

Depth of water level immediately before switching pump off in BB30 = 13.77m

TransmiSsiVitY, T = 306 gallons per day per foot (refer residual drawdown curve

Figure Al6b)

I

Observation Well: BB30/2

I Location 4.6m east of BB30

Depth to bottom of borehole = 38.5m

Depth to top of Glen Munro/Woodlaflds Hill seam = 25.5m

Thickness of seam = 8.5m

Static groundwater level at 11.94m

I

Depth of water level immediately before switching pump off in BB30 = 14.50m

TransmissiVitY = 300 gallons per day per foot (refer residual drawdown curve

I

Figure A16c).

I I

Borehole: BB28 Date: 9 November 1977

Depth to bottom of borehole = 160.99m

I Depth to top of Glen Munro/WOOdlands Hill seam = 22.9m

Thickness of seam =8.49m

Depth to top of piercefield seam = 141.49m

I U

I I I I I I I I I I I I I I I I I I I I

- 24 -

Test 3 (continued)

Thickness of seam = 17.84

Static groundwater level at 14.82m

Pumping level at 33.Om

Average pumping rate = 15 gallons per minute

Pumping period = 12 hours

Transinissivity, T = 132.6 gallons per day per foot (refer residual drawown

curve Figure A17).

- 25 -

LIST OF APPENDIX FIGURES

Figure No. Title

Ala Explanatory Notes - Engineering Log -

Cored Borehole

Aib Key to Engineering Logs - Cored Boreholes

A2 - A14 Engineering Logs - Cored Boreholes

A15-A17 Residual Drawdown Curves for pump-out tests

A18, A19 Results of Slake Durability Tests

A20, A21 Estimates of pit inflow rates for pump-out

tests in boreholes BB28, BB33 and BB32

I I I I I I I I I I I I I I I I I I I I

EXPLANAtORY NOtES: ENGINEERING LOG CORED BOREhOLE

DESCRIPTION OF CORE

All rock types and stratification spacings have been classified according to definitions below (from: McMahon, Douglas & Burgess - Engineering classification of sedimentary rocks in the Sydney Basin", Australian Genmechanics Journal Vol.G5, No 1, 1975, pp5l-53).

ROCK TYPE DEFINITIONS

ROCK TYPE DEFINITION

Conglomerate More than 50T of the rock consists of gravel sized (greater than 2mm) fragments. Sandstone More than SOS' of the rock consists of sand sized (.06 to 2mm) grains. Siltstone More than 5O of the rock consists of silt-sized (less than .06mm) granular particles and the rock is not laminated. Claystone More than 505 of the rock consists of clay or sericitic material and the rock is not laminated. Shale More than 50 of the rock consists of silt or clay sized particles and the rock is laminated.

STRATIFICATION SPACING

TERW SEPARATION OF STRATIFICATION PLANES

Thinly lam i na tech <60 Laminated 6mm to 20mm Very thinly bedded 20mm to 60mm Thinly bedded 60mm to 0.2m Medium bedded 0.2m to 0.61T) Thickly bedded 0.6m to 2m Very thickly bedded >2m

WEATHERING

Degree of weathering is represented in histogram form which indicates the general trend of weathe'- ing. Bands of significantly smorehighly weathered material are noted in 'Description of Core'. Definitions of degree at weathering used throughout are:-

DEG.gEE OF WEATHER I MG

APBPFVIATI°°4 - DEFINITION

Fresh Fr The rock shows no discolouration, loss of strength or any other effect due to weathering.

Slightly SW The rock is slightly discoloured, but not noticeably lower in strength than fresh rock.

Weathered

Moderately MW The rock is discoloured and noticeably weakened, but 100mm diameter drill cores cannot usually

Weathered be broken up by hand, across the rock fabric.

Highly NW The rock is usually discoloured and weakened to such an extent that 100mm diameter drill cores

Weathered (wet) can be broken across the rock fabric readily by hand. Wet strength usually much lower than dry strength.

Extremely EW The rock is discoloured and is entirely changed to soil but the original fabric of the rock is

Wea the red mostly preserved. The properties of the soil depend upon the composition and structure of the parent rock.

DEFECTS

All dips are measured from a plane perpendicular to the axis of the core. Joints are indicated graphically at appropriate RL and dip and are described in 'Description of Defects". Other defects e.g. bedding partings and fracture zones, are indicated by short horizontal lines along the left side of 'Description of Defects column. Individual bedding partings are generally not described; hence, defects indicated should be assumed to be bedding partings unless described otherwise.

DEFECT_SPACING

Defect spacing is represented in histogram foram. Spacing has been calculated for zones through which the spacing of natural defects is shmul lar.

POINT LOAD TEST DATA

Strengths plotted are those measured perpendicular to bedding converted to Is(SO)values (Ref: Broch & Franklin The Point Load Strength Test"-Int.,J.P.ock Mach - Min.Sci. Vol .9,pp669-697)

STRENGTH CLASSIFICATIONS

Extremely Very ow Low Medium High Very High Extremely

EL M H VII EN

Strength Classiricatiorm

Abbreviation

0.3 3 10

Anisotropy indices calculated where tests done at 90° and 0° to bedding. Where strength parallel to bedding is greater than strength perpendicular to bedding, anisotropy index is asterisked. lihere more than one anisotropy index can be calculated for a earticular secti on ( j . e. more than one test done in either/or both directions) both values are recorded if ratio is greater than 1.25 but are averaged if less than 1.25.

a FIGURE Ala

I I I I I I I I I I I I I I I I I I I I

KEY TO ENGINEERING LOGS - COBED BOBEHOLES

Sandstone: grain size indicated on description of core

Conglorrrate

Siltstone

Mudstone

Carbonaceous Carbonaceous traces and

Mudstone coal wisps indicated by:-

Siderite band

Clays tone

Coal

NERAL NOTE: Legend used was according to "Graphic Representation of Coal Seams' /\ust Standard K183 - 1970, 8 pp. with the exception that coal types were not differentiated.

All coal scams were blacked out.

See attached sheets.

FIGUBE ATh

ENGINEERING LOG - CORED BOREHOLE BOREHOLE NO.: L 24 Sheet / of 6

Borehole location: R. L. Surface: 92571n Grid coordinates: Job No. : /023 - 00/ - 70

N. /3877555.9 Client : R. MIsLE 4'! Co PTY LTL) E: 30452s 85 Datum: A - I-i. b. Project : MT 7 /oRy, LE,tsE

Location : .S/NLEroN, A/sw Borehole inclination Borehole direction: 0° (From horizontal):

Hole commenced Drill type : REFER R. W. Log describes all strata recovered El Hole completed . Mounted on RECORLS including soil over rock.

Supervised by Drilling fluid

Log checked by : Barrel type : For log of strata over rock see Engineering Log - Borehole

POINT LOAD

Z . TESTDATA

DESCRIPTION OF cr E

DESCRIPTION > Cl) Ir I-

DZO 2 DRILLING

CORE I OF <E cc

o DATA&

DEFECTS u:t 00— COMMENTS

2 10 50 200

0 1 5 1201,005

2 -

4-

1;

8

>-

cE3 /0-

/2 -

SANbSTONC: f/ne /*3/)/q fractured sand mat- ' 14

1,3

SAin.s TONe 5/Ts70c1s. thfer/aminatczd and 4?f&rb&a'rJ,2d

1 *

5ANDST0NC: pale ?rg. 5rti:r?a'. modena/e& hard, ifepbedded -.---: I

Muds/t,rje baid ai óase

-1--- COA4 S5.4M.' 2. maf WHYBROW 54M 7'h/k /c1i7'/7 /h7'arca/a?417s ,,f Szd,men/s 24"/a 9'searn 6 dtb, 5at7a'S 0 4550

L aysc 5a,?d: a. /85m - FR --- - SW

HW

MW FIGURE A2 EW-

I

I

I

I n u

I I I I I I I I I I I I I i-i I

ENGINEERING LOG - CORED BOREHOLE BOREHOLE NO.: L24 Sheet 2 of S Borehole location: R. L. Surfacer Grid coordinates: Job No. : /023, - 00/ 70

N: Client : R. W. /LR Co P7)' L77) E: Datum: Project : MY, 7-H0L6 y 1_EAE,E

Location : 5INc*1E7-oAi, N Ltl Borehole inclination Borehole direction: (From horizontal):

Hole commenced : Drill type : RIE FER e W. /VIILL.ER i-i Log describes all Strata recovered

Hole completed : Mounted on : L_..J including soil over rock.

Supervised by : Drilling fluid

Log checked by : Barrel type : For log of strata over rock see Engineering Log - Borehole

POINT LOAD o . TESTDATA

DESCRIPTION OF rr DESCRIPTION DRILLING

CORE I- i OF <E g DATA&

W Lii 0 DEFECTS COMMENTS

(9 U)

2 10 50 200 U) -

2 0100500 1 5 1201,001510 Of

AJ Only dimnfs jr&zter i'/?an 1 - 0. / iz 1h/c1(n.S'8 shown.

. SANASTONE pa/5vri.j, /? 9ra(n2d, Thodrcle(y /7ara', 7 -/in/q lo/'r5dc/d o.nd /cfr/or77/nCtea

Madstcn £5cn0(s ct op a,'o' :

bo/±orn, moderately so/I 710 ½arS 1/7

24- COAL SAA.' I. iç 'r,tr thth w/s½ /Qhzrca/a I-ions 01e &2d;(r2n/-s -

/ SQ7T) 1

2,2 CLY57b,iE . greyi-th lb t€ly sano(j lbx/zjra In ,oarf,s Z

MU1,s TONE: grec modsnilb(q &

2.0 SILTSTOA/E: q,-ay, moderafafg

2 -. 4AJ0ToNE.' grey 2rne yrainc10 hard.

III

30-,'

grades ,ri€c//an) lb coarse yaiQed -. .

Ccng/omr,.-te prWes /0mm s.

32 - b- -

(Pades 71117e lb med/am, Sandstone modepai/, Mapo'

':. 7' l)fchIy //7terea'ded. 4 r,c/es of 2.2

/1ining wpwards 00riq/omer(9 /a r5c7nas to 0/20m

36

14

MusTo,ig: larkgrej lb grey,

moderalbi sa/ /am;nai.d .8

SANOSTONE: Pa/a gr mad/em 5pa;ned, moa'erate/' ---------- hard.

ri-I i

SW

II MWJI HW I FIGURE A3 EW

I I I Li I I n n H

n

I I I I I I I I I I

2.8

2.5

52-

- ;7;,7-t, clips o°, rnagh, irregular con7',naozJs at

4. top and hot/am.

54-

1.2

5

2.8

BOREHOLE NO.: £24 Sheet of 5

JobNo. : 1023E.-00(- 70

Client : R. W. A'IILLER 4 Co Pro' I713.

Project : MT. 7H0EL5v LEASE

Location : 6lNc1E 7bN, A/SW

Eli Log describes all strata recovered

including soil over rock.

11.1 For log of strata over rock see Engineering Log - Borehole

POINT LOAD

> . TEST DATA

- cc

m I- E- UJif ,. DRILLING

z

CL

DATA&

-

W

rn—lao- ox

COMMENTS z

10 50 200 1 I 5 Izo 1100150 I I -

3.5

DESCRIPTION

OF

DEFECTS

w i

I— - 0- 51: Lu Ui 0

(9

ENGINEERJNG LOG - CORED BOREHOLE

I Borehole location: R. L. Surface: Grid coordinates:

N:

Datum:

I

E:

Borehole inclination Borehole direction: (From horizontal):

Hole commenced : Drill type : REFER R. . M/LLER Hole completed : Mounted on :

U Supervised by : Drilling fluid

Log checked by : Barrel type

I DESCRIPTION OF

CORE

I (Corn'...) .çANL3STONE:

I I I I I I I I I I I

A4UI3STONE $ &4NhST0NE:

lot

Mar/stone : qreg to darl<'yi'ey. tnoderatey sL'( 7'O rnoderafe(j hand.

Sond.s/ofl: gPe/ 7'Opa/e gnr, //na qrained. Car/nac5ou5 mip base

4L SE'v'4.' 0• 5 mztr,z thioë AIUDSTOIVE qvaq to dark noderatef!/ SOj /t' mod. hard.

AN86TOA1E pa/s 9Veq ,/i4s' gr~s/ned.

,(4/JA~ TONE . cm7r6oflao al a.se

CL'1YS7bNE.; g/'egI.th whh'e

M11L3STON . carboriqcec, 9r1, moderate/s, hard ecal

hands t, 80 mm._—__________

CLe >'.STONE gr'ej/sh whi/,

mocJapa/e/1 o1C7

7FITAi5 TO AlE or , Thocirna/zi Carôonaczous a baz

COAL SEAM! 0.24 mec -frh/ak MuOsro,vE gory Ic' dan/c gray

S1/Vos TONE 5/L7ToNE inter laminated So/Eo M(JLt~Tof16: moderately &,'t ~

d4,teg hard. SAl/AS TONE .S/1-7-570'VS: /nler/ami',rr,4d and intanjbrdd&J,

.9I1 ( ,pid tjM.ed.

SAvL STONE: 1'5g, grainad

AIOSTONE 4 SILTS TONE;

Inter/am/na/ed 6 interh,zddd, 5/5o

SAA1b5TONE:

"sy to pa/s yns.y

/2fA to mEd/c/fl7

o7odenate/d hard, y io3addcd.

FR

SW

MW HW EW

42

44.

1.'

ENGINEERING LOG-CORED BOREHOLE BOREHOLE NO,: L24 Sheet 4 of 5

Borehole location: R. L. Surface Grid coordinates: Job No. : I020 - 001 - '70

N: Client R W. MILLER 0 6 PTY iTD. Datum: Project : MT rHoitY 1-EAEE

Location : SfiIOi..E TON NS W Borehole inclination Borehole direction: - (From horizontal):

Hole commenced Drill type : RFE Log describes all strata recovered

Hole completed : Mounted on : RECOROS L_J including soil over rock.

Supervised by Drilling fluid

Log checked by Barrel type : For log of strata over rock see Engineering Log - Borehole

POINT LOAD 0 (3 TESTDATA

DESCRIPTION OF - DESCRIPTION

07, DRILLING

CORE i - OF <E DATA&

DEFECTS 1L 7 00— COMMENTS

(3 2 10 50 250 (15

60 5 20 100 50Q ar <

-rn (Cout ) SANIDSTONE

Car'boaceou6 a//S,O

.......

CoNLo,t-iERArE /usIgi] pe6b/s 1?) 3.Emm. S3e ifS 7 ' 0 Q. 1 .2 Sands m as n/J<'.

64 SANLT01vE. paie7rey. fflEc/itim -

¶aInec/ mOde(Qfe/y hard7

- 6.6 SILYS TONE re to dark

mociet-ri-le/g hard

- ANToNE: pale goe

,77'7diam ±0 coor6e 19cm1'ned, moclei'aS'e/y hara lhiCk& /f7tePbrJcld I

I

-77

?nadzs 74ne sLo med am gmineo' 76

C0NLL0/46RATE pale ló/W5/5 5're, j, pc/ymicf , oeAbles 7's 4oleas .

l in Sand1 rroafrix. Q Sider,te band a! base

7

—,

COAL SEAM. 0. E25 ,17'7friES -IhicJ(.

LB SANbsTONC: pa/c qr, firse .:

grairsed, rnoderatc/7hacJ.

MJô,sroNE moaloi,, 4' SANST0N,e~:

'0e graThed, modafc( hatd. 74

SANcOSTONE S/Lrs701\1 frifr/aminafcd d interbdcicd

7, SANOS TONE pate grøy mdam

gralrsed, shnI5 S4j 7'l'tiCk/y 4 infer,ócc/ded Coarsc and/line yc/e wth' Car/sonaccoas wisp.s.

76 '1.

FR-' Ifl SW --- I MW--Th HW

FIGURE 1A5 EW

I I I I I d I I I I I r

li

P

I U

I I I I El

11M A&M MS B PIOOE

ENGINEERING LOG - CORED BOREHOLE BOREHOLE NO.: 424 Sheet of 6-

Borehole location: A. L. Surface: Grid coordinates: Job No. : /026 - 001 70

N: Client : R.W. MILLER Co TY L70 E: Datum: Project : MT. ThoRI.ay /LEASE

Location : SINc1.67oN NS IV. Borehole inclination Borehole direction: (From horizontal):

Hole commenced : Drill type : R. w. MILLR Log describes all strata recovered

Hole completed : Mounted on : bRiLL/u RgcaRs LJ including soil over rock.

Supervised by : Drilling fluid

Log checked by : Barrel type : For log of strata over rock see Engineering Log - Borehole

POINT LOAD

z 0 0 TESTDATA

DESCRIPTION OF . DESCRIPTION >- I Lu DRILLING

CORE I F- OF <E DATA&

w LU DEFECTS

(/5 Ut _t' 00— COMMENTS

0 2 10 50 200 I- CO co

1 15 20 0050

(c-t ) SAAIOSTO/VP -

82-

Grodos to ine 5ra,nd mociarafEy hard, infor5ecIad 84 wi*? minor SiMs/bne

!1(L/OSTO/vE ry 7,0 dark modera/-aIy so/Y 7 modoTa/a/y 85- hard

. = COAL SEAM: 0.5/6-m ItoL/C. WAMO SEAM /fgTONE COAL 5,w: /.660 natra

MuTsTov: modsratoly off to rnoc/arate/g hard.

2 AA/0STo/'IE mac/IL/rn 5rained

MuOST0,vE: graj 7'0 dark gre',

morto/,, Soft i-c mcc/aratof5 hard.

S4-

SANyoN5 : f2Th5 511/ned

MuisToNea: qraj to c/ark gr&q, IodvLa/i 50(t' to moderata& hard, carbonacgc in parts.

ILTSTOA/E-' gPacj, modamtefy hard, sirJrif& banae,

too SicrS TONE : moderataL,, hard,

FR liii I ISW

MW—UI FIGURE 446 EW

I I I

I I I n

H H I I H I I I I I H

I FIGURE ,A7

ENGINEERING LOG - CORED BOREHOLE BOREHOLE NO.: L32 Sheet / of 5

Borehole location: R. L. Surface: 62. 8(5 in Grid coordinates: Job No. : /02&, - 00/ - 70

N: /35785 63 Client : R.vi. MILE R t' Co PTh' L7D E: 304600. 47 Datum: A. H. t'. Project : MT THoLy LEASE

Location : Su-iQLETON NSIA/ Borehole inclination Borehole direction: 30 (From horizontal):

Hole commenced : Drill type : REFER ,Q.t./ Log describes all strata recovered

Hole completed : Mounted on : RfLL/N RORAS L_J including soil over rock.

Supervised by : Drilling fluid For log of strata over rock see

Log checked by : Barrel type : Engineering Log - Borehole

POINT LOAD o TESTDATA

DESCRIPTIONOF 0 DESCRIPTION cc <o ov

DRILLING ' H >-

CORE — OF <E DATA& LU 0 DEFECTS COMMENTS

w (2

U)

2 10 50 200 I- Cl)

U)

S 20 10050

4-

41

a .

) V Sf 0

0

/0 'U .4 o zi-

12-

SA/VOSTONE: pale grey, med/tim nained.

001VQ10Me4TE po/mc7'fc 00 OIn1 parlia I/

cemented d,o /5 (0f'/I..O,t4CR/tTE j' E.4A/LDSTONE: :à5 11 /nferóedded 5/35

Cnr/ornec'de :peA/uS7'O25n7m.

SOr)d5t00e: med/urn 7O CoapEC rained.

o. CON 0/VIERATE pa/e b/wth Feq, mcdaraAoly herd, ,oeb/ 0

?D 3-00

0 mm 0 side 18 - -

SANST0NE pa/i rsh brown medium -to c.oarse 11ained, modei'atef hard. _____

2o oj

P

P

I

I I I I I I I I L

r-

I P L

P L

P

$-T-__[.1.1 :1 1

ENGINEERING LOG - CORED BOREHOLE BOREHOLE NO.: 1 32 Sheet 2 of 5 Borehole location: R. L. Surface, Grid coordinates: Job No. : 1023G - 001 - 70

N: E:

Client 9 kJ. tv1ILL Co PTY LTD Datum: Project : MT TH0Ry 1_EASE

Location : S-aroN NSL,J Borehole inclination Borehole direction:

)From horizontal):

Hole commenced Drill type : RerE R.W. M11-LER Log describes all strata recovered El Hole completed : Mounted on : bILLst' RECo.n,s including soil over rock.

Supervised by : Drilling fluid

Log checked by : Barrel type : For log of strata over rock see El Engineering Log -- Borehole

POINT LOAD 0 z - 0

> (I)

TESTDATA

DESCRIPTION OF Cr DESCRIPTION I- F- DRILLING

CORE OF DATA&

DEFECTS cc 00— COMMENTS

0 20 50 200 U)

200050 o<

J C0NL0MRAT:

pole Llu,h mocJrcz7'a6( hard,

Po/yrnicl/c pe6//s 7'o 'tOmcn f)

' SI5e In Caap sand ma',h/x.

Th,/<-, 6c2c/ded and maSs/va. '2

22- I 3

1. 2 5l6ToN pale madiam gej ±0 Coaps,a graThad, mac/a haf7d, Th;ok/ f07'izrbea'4led.

CoNcLame/,4Te.' pa/a //7 to /5nms3e 0

SAN0.ST01VE: pale gr rned,thn to Coarsv ,qrained - -

CaNc 0M69A7E SAA/ASTONE 7hcea'g /27* added 60/527,

Cong/omerafe- oa/e /a/shgreg, 30- - - pe6,o/e.s /0 8mm dici. 0

Sandstone : pa/e yf7j. coarSe - 0 0

cirained. 0. 2

SANISTOIVC pa/a greg medium to Coarse graiaed, modenata/j hard.

C0A/cL0M5R4TE. pa/a &'uIShgrseJ. lo..o27 ,oebblas *0 20mmn a'/ci. .°. .2

0 SAA/osrot/E Coarse grainteci

CoNz-oMERATE: peA'ilss 'o 20mci dici. :o.

- $ANOSTOA/E 7m/ne 70 med/arr : :: grojnad. :. -.•. 1.0 2

s CoLoM,ATa: ,00/e 614116/i gre 0 -C

-o-2-

c/, e66/es to moclerafe/y /lar p 0 22n-m dia.

SAiJs.s7-aNe: (flaa'if to ______ :-r-:- graft7ad I I

- C0N0/1EA7-E . pe./as to 1517'm dic7. -

SANOSTONE pa/a greg.

Lmum gmiY. 4

FR

I Sw MW—ill FIGURE A8 W— I

L

I H I

I I I I I I I H F I I I H I

ENGINEERING LOG - CORED BOREHOLE BOREHOLE NO32 Sheet 3°f -

Borehole location: R. L. Surface, Grid coordinates: Job No. IO23, 001 -

N: Client R.W. MILLCR TO. E: Datum: Project : Mr. ThOltLaY LEASE

Location : Borehole inclination Borehole direction: (From horizontal):

Hole commenced : Drill type : MILL.Ef Log describes all strata recovered

Hole completed : Mounted on : ORILLINC, RECOKb.S L_J including soil over rock.

Supervised by : Drilling fluid

Log checked by : Barrel type : For log of strata over rock see Engineering Log - Borehole

POINT LOAD

Z 0 z—. TE ST DATA

CL DESCRIPTION OF Cc DESCRIPTION DRILLING

CORE i - OF <E DATA&

w DEFECTS _' COMMENTS

0 Ci)

2 CO 50 200 } (1) (Oz -

5 20 ioojso

.SANO STONE 00NL0MA7-

Thickly ,,7tepbedded SO/Sc, :0.; .3

ndstone : pale jn coan 10 .

-- grEtined

Con/omrafe:pa/e b/uihn 47 :ä - p.Lb/a.s up to /crrini

:— I.e

SAArnSTONE: 7L,e grsned SILTSTO,vE: rncderate(y

4.

SAivo.srovE.' pale qrey,L/ne hard1 9Pa/naa rnoda'rate/y -

fOfer/aminated and tddeO' wit/i Ei/i'.s/'Ofle (/o7). 35 &ic,d X 1.0

C Mudone o base. 46

/nt da 75° c/cI and / planar.

48 26

- . 60

52

3.9

54.

8.0

COAL 5AM: 4.7/5 lnefrvns WhY8Roi SEAM

-lhic/ç Th1r'cn/ahons s&frnants 378%, ofeqm

4 Mudstoria bards 'o.66m -i

4 Clays/-one /iand,s :0.34,s,

/ &/-/stone iands

M& On/u drnen/.s eat ifioo o .in +hicknes Shown = =

I-H - II SW --- II MW—Il FIGURE A9 HW-1 I EW

I I E I I I I

I I D I I I P L

P

H H I I

ENGINEERING LOG - CORED BOREHOLE BOREHOLENO.: 132 Sheet4of 5

Borehole location: R. L. Surface: Grid coordinates: Job No. : /023 - 00/ - 70

N: Client R. W. tS1/LLE Co Y L770 E: Datum: Project : MT T(op,y L0AS

Location : lALETb.j t'tsvi Borehole inclination Borehole direction: (From horizontal):

Hole commenced : Drill type : REFER F w. MILLER Log describes all strata recovered

Hole completed : Mounted on : DRILLINeT RCCOROS including soil over rock.

Supervised by : Drilling fluid

Log checked by : : Barrel type For log of strata over rock see Engineering Log - Borehole

POINT LOAD 0 . ° >U)

' cc0cl TEST DATA

rL DESCRIPTION OF ° DESCRIPTION I- -_ DRILLING

CORE - OF oE W 6 Ze w

0 X

DATA&

DEFECTS J u - Hw 00 COMMENTS

60 0

l_

2 :o 50200 I 5I05555

C/)

CLAY5TO NE. gí'eclish wh,'ta, - sof modøc'cz a/ hard.

.4

Si/tstcna and &,ncis tone bards at Lose. -- COAL. .SOA/t4. 0.7ei mefres

2/h intercakri4o,zs o/' Sediments 348 % eSeaM

64 SAIVOs-roNe. pale i'ej, a to med/am 'ed', tely I hard, rl7assíve, 1hc4/ &dded, Car,5o,-10 Ceous 7LraeS

(16

1.6

70

£c'ades a'lum to coarse - gra/ned.

72 CONLOM,ERATE: pa/a L/aih 0 0 5ra,, ,oe66/a.s t0 20 mm oa. l a

.9 SAlvOs TO/yE pa/a yrey, med/am t coar ,ned

74 -.

pole //aith 00 grey, ,oe&5/ag to 10mm dia.

* 1.1 SANOSTONE., pa/a med/am to camseQ1'.ir7ed,

7 moderafe/, , hard, it,/ In

7c5 -

FR SW Mw—

FIGURE AIO

I i I I I I I I I I I I I H I I I I H Li I

ENGINEERING LOG - CORED BOREHOLE BOREHOLE NO.: L32 Sheet 5of 6

Borehole location: R. L. Surfacer Grid coordinates: Job No. : I0231. - 001 -

N: Client : R.kJ. M(LLER Cco PY L.TC) E: Datum: Project : MT. YHORLEY L-EASff

Location : SlN35rErO . Nsj Borehole inclination Borehole direction: (From horizontal):

Hole commenced : Drill type : REFER R.lI. M(LLER r-i Log describes all strata recovered

Hole completed : Mounted on : c RE.CORt. LJ including soil over rock.

Supervised by : Drilling fluid

Log checked by : Barrel type : For log of strata over rock see Engineering Log - Borehole

POINT LOAD w Z -

0 0 >-

TESTDATA

DESCRIPTION OF - DESCRIPTION - DRILLING

CORE I I— i OF 0 Lu <E DATA&

DEFECTS COMMENTS

0 2 15 50 200 5 20 100

(Conk ) SANOTONC 5

82

84

S,LrTONC : 5rj, mod hapd.

- . . OIo) /5

I.8

CLAYSYQtvE.- pEla 3reqid broLcjn, so/f 7'o modaa t

_-

hard.

SANtSTONF S/LT5710fvE: litter-/a minahzd 5/35 {ine rautea',1oo/a f1efJ

ünd modrrahe/ hard. K 2.3 30

MUteTOAIE. dark qmodea.fe, $Q7C modarate , ,ard = COAL SEAM 0 750 in

ft7,erk.

52 x 5.5

MilEsTONE:

S14Ni2r57oNe- 1 9(L7ST01VE -- // a'cJild ,ht-rlamia fed,

5 /36, 4½e g/?2/02d saads/ane

S14AIDSTONE 0040 3p, 7Lie -777777

ln med/tim qranaa' moa'erafe/y

harl.

.4 SA WAS TONE 5/L7TONE: /nlzr/aminat'ed g nf-bzidder/,

735 Hi-I--- .Jofrtt, dip.a 40,

andsone: grrj, m'-iaa' JOfr4S 2o /'oens,a'€I _

TOiiJtcJ(ps4O sfi3hs'/j i a — — S/ic..f-tsi dad

darkyre, p.?Odra70ef.y ocd

COAL SEAM.' O-&SSm i'hicIc. 38

SA,VATO AlE c# .S,L.TSTONE lnfarbea'ded ' /n7'en/anhittahad

X 1. 1 SA v s in NE: pofa :• - meditim rir?ed. /

FR -

SW— MW FIGURE All HW—EW

IMATAIMIES 0 miuoo

I I I I I I I I I I I I I I I I I I I

flJS B WUOOE

ENGINEERING LOG — CORED BOREHOLE BOREHOLE NO.: 028 Sheet / of 3

Borehole location: R. L. Surface: 8. 50,,, Grid coordinates: Job No. : /0236 — 001 — 70

N: 1336750 Client : R. W. A411LER d Co Pry L70. E: 3o32503/ Datum: A.H.b. Project : M77. YHORLeY ZEASE

Location : SINLE70/y , /V,5.)/.

Borehole inclination Borehole direction:

(From horizontal): .900

Hole commenced : Drill type : Repee R.W. M/LLR Log describes all Strata recovered

Hole completed : Mounted on : DR/z.11v4 REOR0S. L_J including soil over rock.

Supervised by : Drilling fluid For log of strata over rock see

Log checked by : Barrel type : Engineering Log - Borehole

POINT LOAD

Z 0 >.. TESTDATA

F- LU

DESCRIPTION OF .. DESCRIPTION I— DRILLING

CORE I I OF <E cc

DATA&

W DEFECTS 00— COMMENTS

0 C')

2 10 50 200 F- "z

5 20 0055

Sl.rr SAND) r/ed,ii,n /0 ccars.e grained, pale brown.

C0AIL0MERA,TE.- poIyrsia tic cC'. ,oeL5b/e 1b 40 rrm. - . •. O Saó- anqil/ar to &ib- pounded.

Coo rse rno"). .auid a - 0.

00 o.

Muosroiis: 6rown Ia yreyish brown, Silly l pal' ts = 2.7

SANDSTONE 5ILT.ST0NE: ipterbea'cJed ' ,,tar/arn/naied

a/4o,

Sana stone: pate Lsroag) /2 .:.: .4 med/am grained

paralleL, sob- vertical, Si//stone; qrej to •greyisJ) frOWO

5Zm, sub-vent/cal. plane', minor Calcite lifsJl/ng,

dis *inuau a1 1-op, I

SANOSTON: pale brown, ine 14 - -to medium grained, bard and . : ps've. -

. 1

cainuoua' topI lo/tcm, generally qht. Sea/ed, ape"

-: /

. in pads, planar $

Medium I-a caar grained :, . .:• .0

rades /th l-o qreqish .s/ ornt,.sats-verfica/,apen, T:T.T brown, 'ne iInaaç Sidy ifl f, - :.: :- roLlyl,, planar, cont/nuau

at tap 607'7,77. 4t Or15.

iiwwwJi'2 FR sw

N

MW FIGURE 412 HW EW

I I I I I I I I

I I I I I I

I I I

KDA&MRS & FOOE

ENGINEERING LOG - CORED BOREHOLE BOREHOLE NO.: 028 SheetEof 5

Borehole location: R. L. Surface: Grid coordinates: Job No. : /036 - 00/ - 70

N: Client : R.kf. MILLeR Co Pry 47Z.

E: Datum: Project : MY. NORftY LCASE Borehole inclination Borehole direction:

(From horizontal): Location : £/N44_e7-o,v • N I-V

Hole commenced : Drill type : Log describes all strata recovered El Hole completed : Mounted on : including soil over rock. Supervised by : Drilling fluid

Log checked by : Barrel type : For log of strata over rock see Engineering Log — Borehole

POINT LOAD

Z E 0 0 0 Q. TESTDATA

Zo —

- CL DESCRIPTION OF DESCRIPTION F- F- DRILLING

CORE I I— LU

i CL

OF cr

DATA&

DEFECTS u, u. 2 t' n COMMENTS

tO 2 10 50 200 0 co —

5 20 105 5

Gradze to pole /-own, M2dium, Zo T t gi'ained I I 1.5

(rades -to pale qrey ne groined wi/h s,der,fe bond at 22 iocrri- ve't,ca/ -to ó / End of /,monfl Cenfre. .•;• ve1--hc01, opn,rou5, / planar hmoni/e stained. 1.2

Land Of ygy Si/lstone. 24

Cartsonaceous 74'aces iii hard, ma5j homojaneou -

1.2

San d.s/orie

- .1-

Crodes /',-j, o nye,J/im gre/ned * Scndsti,ae, wit/i minor - baod. T.

.4

30-

- -..: ..- 2.1

COAL .SEAM : 3. wifts WI-IYBROF- AM inferea/ations of Sediman/, 14-2% of team

2 C/ajs1ooe bands:0.2lm 34

in Micistane bands -. 0.25rn

N-s: On& sediments grter lt,an 0 f,-, -/hickne&s Shown

MUbSTo-iE - pale grey 1'o grey- 5AA/bSTO/JE; pale 52 /Iyv /h

hum 4.2

,Mun sroNe - Car-baflaca5 in parts.

COAL 5EAM: /.26-pnefYgs hik

41 it 2.1 FR

UIAI FIGURE AI EW 1

I I I I I I I I I I I I I I I I I I I I

IMANAMMS 0 M001140

ENGINEERING LOG - CORED BOREHOLE BOREHOLE NO.: 028 Sheet 3 of 3 Borehole location: R. L. Surface: Grid coordinates: Job No. : 10236 - 00/ - 70

N: Client : R. W. /l1/LLER CoPT)' L7() E: Datum: Project : M7 7-H0RLIY E4S

Location : SINLToN Borehole inclination Borehole direction: (From horizontal):

Ze commenced : Drill type : iii

Log describes all strata recovered

e completed : Mounted on : including soil over rock.

Supervised by : Drilling fluid

Log checked by : Barrel type : For log of strata over rock see Engineering Log - Borehole

- CL TESTDATA

DESCRIPTION OF 0

E —

DESCRIPTION DRILLING

I

PO IN T LO AD

CORE w I I— OF Zo

)

CL 0 DATA&

W DEFECTS cc

W LU f_ COMMENT S W

0 —

I- cj 2 10 50 200

1 1 5 120 100j50

Cl) 0 Z —

) Cf j.slone MUbST0iNE I

Hcia rE.R41M,.4TE1 &4c.3e0,T?.

42 -

I Sw MW—i! ! I FIGURE /:i4 EW -i

I L H I H I I I I I F F F I Li I I I H

2.8

4 ___ -- V GWL —o--o-

\

RESIDUAL DRAWDOWN CURVE:

\ PUMP WELL BB32

6 AVERAGE PUMPING RATE Q

= 9 GALLONS PER MINUTE

TRANSMISSIVITY, T = 264Q

Ls

T=43.9 GALLONS PER DAY PER FOOT

8

10- S = IS. 5 metres

= 54.1 feet

E

z 12-

0 0

0

-J

0 Ci) w 0

'0

I 2.5 5 10 100 300

RATiO, T(timeafterstartingtopump,minutes) -

T(time after stopping pump, minutes)

B

F(GURE A5 - ---

-

\ RESIDUAL DRA'NDOWN CURVE: PUMP WELL BB 30

° AVERAGE PUMPING RATE, Q = 8.95 GALLONS PER MINUTE

TRANSMISSMTY, T = 264 Q

Ls T= 70.6 GALLONS PER DAY PER FOOT

0

4-

5-

U,

- £s' = I0.2m

= 33.46 ft

C')

;! 7-

0 a

Ix a

8- -J

a U)

9-

I:

0 o

12- I 2 10 100 200

RATIO, T time after starting to pump, minutes) . T'(time after stopping pump, minutes) Ft GURE 416 a

I I I I I I I I I I I I I I

I I I I I

IC

0.2

0.4

0.6

0.8

2

MOM

RESIDUAL DRAWDOWN CURVE: OBSERVATION WELL BB30/1 (12.2m East of BB3O)

AVERAGE PUMPING RATE, 0 8.95 GALLONS PER MINUTE

TRANSMISSIVITY,T = 2640 Ls'

T = 306 GALLONS PER DAY PER FOOT

0

L\s'=. 2.35m

= 7.7IOft

10

100 RATIO , (time after starting to pump, minutes)

(time after stopping pump, minutes)

FIGURE A 16b

I I I I I I I I I I I I I I, I I I I I I

i 0.2

0.4-

0.6-

0.8 -

I .0-

1.2-

0)

1.4-

1.6- 0

0

-J

0 2.0-

2.2-

2.4-

2.6

2.8

0.5 2

RESIDUAL DRAWDOWN CURVE \ OBSERVATION WELL BB 30/2

\ \ (4.6m East of BB30)

\ AVERAGE PUMPING RATE

8.95 GALLONS PER MINUTE

\\ TRANSMISSIVITY, T =

\ Ls' 0 T= 300 GALLONS PER FOOT PER DAY

I

2.40m = 7. 87ft

10 tOO RATIO , T (time after starling to pump, minules)

T (time otter stopping pump, minutes)

B OE

FIGURE A16c

2 -...

I RESIDUAL DRAWDOWN CURVE

\\ PUMP WELL 8828

I AVERAGE PUMPING RATE , Q = 15 GALLONS PER MINUTE

I' TRANSMISSIVITY, T = 2640

Ls, 4 T 132.6 GALLONS PER DAY PER FOOT

I I

I0

= 9.1m

= 29 86 ft

\\\\\

co Lu

10 100 300

I RATIO, T time after starting to pump, minutes)

T (time after stopping pump, minutes) IMMMIES B

FIGURE A17

1

RESULTS OF SLAKE DURABILITY TESTS

Borehole Depth

Rock Type Durability Classification

(in)

AA24 55.67 Siltstone

AA24 95.97 Conglomerate

BB24 74.20 Medium-coarse Sandstone

BB28 56.80 Laminated Sandstone/ Siltstone

BB28 126.54 Medium Sandstone

BB28 160.14 Interlaminated Sandstone! Siltstone

BB32 44.50 Siltstone with carbonaceous wisps

L32 37.83 Medium-coarse Sandstone

L32 45.63 Laminated Sandstone/ Siltstone

L32 50.53 Laminated Sandstone/ Siltstone with carbonaceous wisps

X28 46.3 Fine Sandstone with carbonaceous wisps

X28 72.6 Fine Sandstone with carbonaceous wisps

Z24 137.84 Carbonaceous Mudstone

Z28 180.55 Interlaminated Sandstone! Siltstone

Z32 168.32 Interlaminated Sandstone! Siltstone

Medium High

High

Very High

Very High

High

Medium

Very High

Medium High

High

High

High

Medium High

Medium High

Medium

The object of the slake-durability test is to assess the suseptibility of a

rock sample to breakdown when subjected to cycles of wetting and drying.

The apparatus consists of a drum with 2mm mesh wall which rotates at 20r

on a central axle in a bath of water.

Figure 7,13

The procedure for the test is to prepare ten rounded pieces of the rock sample

of approximately 50g each, oven dry them, then place them in the mesh drum and

rotate for 10 minutes. The drum and contents is then removed from the water

bath and oven dried to a constant weight. The sample is subjected to the

wetting and drying cycle twice. Sample weights are recorded after each

drying. The slake-durability index (second cycle) is calculated as the

percentage ration of the final dry weight to the initial dry weight, thus:

Slake-durability index Id2 = Final dry weight

100 Initial dry weight

The rock durability is classified from the Slake-durability Index, ranging

as follows:

Id2 (%) Classification

0 - 30 Very low

30-60 Low

60 - 85 Medium

85 - 95 Medium high

95 - 98 High

98 - 100 Very high

Figure A19

- - - - - - - - - - - - - - - - - - - - TABLE: ESTIMATES OF PIT INFLOW RATES (GPM) FROM THE

GLEN MUNRO/WOODLANDS HILL SEAM IN THE PUMP-OUT TESTS

FOR BOREIIOLES BB30 AND BB32

Borehole Inf low Rates (GPM) for Pit Dimensions: Width (Metres) x Lengths (Metres)

No. 30m x 30m 30m x 30m 30m x 1500m 30m x 1500m lOOm x lOOm lOOm x lOOm lOOm x 1500m lOOm x 1500m

After 100 After 1000 After 100 After 1000 After 100 After 1000 After 100 After 1000 days days days days days days days days

BB28 3 2 13 5 4 3 13 6

3B30 21 17 55 26 29 21 61 31

EB32 4 3 19 7 6 4 20 8

- - - - - - -. - - - - - - - - - - - - - TABLE: ESTIMATES OF PIT INFLOW RATES (GPM) FROM THE

GLEN MUNRO/WOODLANDS HILL AND PIERCEFIELD SEAMS

IN THE PUMP-OUT TEST FOR BOREHOLE BB28

Borehole Inflow Rates (GPM) for Pit Dimensions: Width (Metres) x Length (Metres)

No: 30m x 30m 30m x 30m 30m x 1500m 30m x iSOOm lOOm x lOOm lOOm x lOOm lOOm x 1500m lOOm x 1500m After 100 After 1000 After 100 After 1000 After 100 After 1000 After 100 After 1000 days days days days days days days days

BB28 51 40 176 80 72 52 191 79