EIS 457 ABO19 120 Proposed Lady Hampden silver/gold mine ... 457... · gold from ore mined by open...
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EIS 457 ABO19 120 Proposed Lady Hampden silver/gold mine project, Drake environmental impact assessment.
Transcript of EIS 457 ABO19 120 Proposed Lady Hampden silver/gold mine ... 457... · gold from ore mined by open...
EIS 457
ABO19 120
Proposed Lady Hampden silver/gold mine project, Drake
environmental impact assessment.
(2 PR1MA1 INDUSTRIES
DEPARTMENT OF MINERAL RESOURCES
PROPOSED LADY HAMPDEN SILVER/GOLD
MINE PROJECT DRAKE
ENVIRONMENTAL IMPACT ASSESSMENT
REPORT No. GS 1984 /340
GS 1984 I 340
PROPOSED LADY HAMPDEN SILVER/GOLD
MINE PROJECT DRAKE
ENVIRONMENTAL IMPACT
ASSESSMENT
NEW SOUTH WALES DEPARTMENT OF MINERAL RESOURCES
SYDNEY, SEPTEMBER, 1985.
GS 1984/340
FOREWORD
Mount Carrington Mines Limited proposes to recover silver and
gold from ore mined by open cut from the site of the former Lady
Hampden mine, located near Drake in the Clarence River Valley in
northeastern New South Wales. Up to 1.0 million tonnes of ore
will be mined by open cut and a further 0.5 million tonnes of ore
may be mined by underground methods over a 6 year period. A
treatment plant will treat the ore at a rate of about 250,000
tonnes per year, and silver/gold bullion will be transported from
the mine.
Mount Carrington Mines Limited is the registered holder of a
number of leases over the project area and has lodged
applications for additional mining leases and a mining purposes
lease. The Company's Mining Lease 346 (Act 1973) granted in
satisfaction of Mining Lease Applications 24 7-254 (inclusive)
264, 273, 274 and 277 (Tenterfield) has been found to be of no
effect. Consequently the applications remain to be dealt with.
The applications need to be granted by the Minister for, Mineral
Resources and Energy, and approval to mine to be given by the
Minister under "plan conditions" in the granted leases, before
mining can commence.
The project area lies within State Forest in Tenterfield Shire
but no environmental planning instrument applies to the area.
Under Part V of the Environmental Planning and Assessment Act,
1979, and its Regulation, 1980 the proposed mining operation is
an "activity" for which the approval of a Minister is required
The Minister for Mineral Resources and Energy is the "determining
authority" under Part V.
In accordance with Section 112(1) of the Environmental Planning
and Assessment Act, the Minister determined that the operation
was likely to have a significant effect on the environment and
requested the then joint venture partners, Mount Carrington Mines
Ltd and Aberfoyle Exploration Pty Ltd to prepare an Environmental
Impact Statement. The Statement was publicly advertised and
exhibited by the Department of Mineral Resources in July 1984 and
public comments invited. Submissions by a number of government
agencies were received.
GS 1984/340
The Department has prepared this Environmental Impact Assessment
Report in accordance with Clause 64 of the Regulation. It
examines the environmental impacts of the proposal and considers
submissions received from and the views of, the Department of
Environment and Planning and other State and local government
bodies. This report will be sent to the Company, the Tenterfield
Shire Council and to all government bodies which provided advice.
This report constitutes the Department's recommendations to the
Minister for Mineral Resources and Energy for his consideration
in making a decision on the proposed mining operation. The
Minister's decision has been included in this document.
G.Rose
Secretary
Department of Mineral Resources
GS 1984/340
PROPOSED LADY HAMPDEN SILVER/GOLD MINE PROJECT, DRAKE
ENVIRONMENTAL IMPACT ASSESSMENT
r'(Th?Tm r..Tm
DECISION OF THE MINISTER FOR MINERAL RESOURCES AND ENERGY
Page
1.0 INTRODUCTION 1
2.0 PROJECT DESCRIPTION 4
2.1 Geology and Resources 4
2.2 The Project Proposal 5
2.3 Infrastructure and Ancillary Services 10
2.4 Employment 11
I 2.5 Environmental Management 12
3.0 EXISTING ENVIRONMENT 15
3.1 Climate 15
3.2 Drainage and Water Quality 16
3.3 Soils 17
3.4 Vegetation 18
3.5 Fauna 18
3.6 Aboriginal Archaeology 19
3.7 Land Use 20
3.8 Existing Noise Levels 20
4.0 REVIEW OF SUBMISSIONS 21
4.1 Members of Public 21
4.2 Local Government 21
4.3 Government Authorities 21
GS 1984/340
Page
5.0 ASSESSMENT OF ENVIRONMENTAL IMPACT 33 5.1 Vegetation and Terrestrial Fauna 33 5.2 Aquatic Biota and Water Quality 34 5.3 Specific Impacts from Mining Proposals 35 5.4 Specific Impacts from Milling Proposals 36 5.5 Noise From Mining and Milling Operations 36 5.6 Social Impacts and Benefits 39
6.0 ENVIRONMENTAL SAFEGUARDS AND MANAGEMENT 41 6.1 Proposed Water Management Scheme 41 6.2 Proposed Solid Waste Management 53
and Rehabilitation Schemes
6.3 Environmental Safeguards 60
7.0 CONCLUSIONS AND RECOMMENDATIONS 64 7.1 Conclusions 64 7.2 Recommendations to the Minister for 65
Mineral Resources and Energy
APPENDICES
Newspaper advertisement relating to
public exhibition of EIS
Requirements of the Director, Department of
Environment and Planning
FIGURES
Locality Map
Proposed Mining Operations and Surface Facilities
Lady Hampden Open Cut - Section 960
Proposed Flowsheet
Clarence River Basin and Regional Drainage
Proposed Water Management Scheme, Lady Hampden
GS 1984/340
DECISION OF THE MINISTER FOR MINERAL RESOURCES AND ENERGY
Whereas -
Mount Carrington Mines Limited is the registered holder of
Mineral Lease 5883 (Act 1906), Special Lease 409 (Act
1906), and Mining Purposes Lease 24 (Act 1973); and is the
applicant for Mining Lease Applications 598, 628 and 629
(Inverell) and 247-254 (inclusive), 264, 273, 274 and 277
(Tenterfield).
The lease applications if granted would confer on the
registered holder the right to mine in the lease areas
subject to the terms and conditions contained therein. In
addition, the registered holder has applied for approval to
mine pursuant to the "plan conditions" contained in ML
5883 and SL 409 which do not permit mining, which if given would permit the registered holder to mine in the lease
areas subject to the terms and conditions contained
therein. Also, the registered holder has sought the
inclusion of an additional mining purpose in MPL 24.
The registered holder has applied to the Minister to be
permitted to mine by open cut methods within the above
lease and lease application areas, and to take therefrom a
maximum total of 1,500,000 tonnes of ore (hereafter
referred to as "the proposed operation").
The proposed operation is an "activity" within the meaning
of Part V of the EPA Act, the Minister is a determining
authority within the meaning of that Part and the
registered holder is a proponent within the meaning of that
Part.
The Minister in considering the proposed activity examined
and took into account to the fullest extent possible all
matters affecting or likely to affect the environment by
reason of that activity and concluded that the activity was
likely to significantly affect the environment.
GS 1984/340
6. No final decision was made to authorise the undertaking of
the activity until -
the Minister obtained examined and considered an
environmental impact statement entitled "The Drake
Joint Venture - Environmental Impact Statement" dated
June 1984 in respect to the activity, prepared in the
prescribed form and manner by or on behalf of the
proponent.
a copy of the said statement had been referred to the
Secretary, Department of Environment and Planning.
notice as provided for in Section 113(1) of the EPA
Act was given and the period specified in the notice
had expired.
the Minister had examined and considered the
representations made in accordance with Section
113(2) of the EPA Act.
the Minister had complied with Section 113(3) of the
EPA Act by referring all representations received to
the Secretary, Department of Environment and
Planning.
7. No notices were served on the Minister by the Secretary,
Department of Environment and Planning pursuant to Section
112(1) (d) and (e) of the EPA Act.
8. The Minister caused to have prepared by the Secretary,
Department of Mineral Resources for the purpose of
Regulation 64 of the Environmental Planning and Assessment
Regulations, 1980 a document entitled "Proposed Lady
Hampden Silver/Gold Mine Project Drake - Environmental
Impact Assessment" (hereafter referred to as the report)
9. The report contains a recommendation that the activity be
authorised and be subject to conditions.
GS 1984/340
Now therefore, I Peter Cox, Minister. for Mineral Resources and
Energy having complied with the provisions of Section 112 of the
EPA Act and the regulations made thereunder and being satisfied
that, with the safeguards proposed, the undertaking of the
activity will not detrimentally affect the environment, have
decided in accordance with the schedule below to a) authorise
Mount Carrington Mines Limited, being the registered holder of
Mineral Lease 5883 (Act 1906) and Special Lease 409 (Act 1906) ,
to mine by open cut or underground methods within, and subject
to, the conditions of the said leases and the additional
conditions to be attached thereto; b) approve of an additional
mining purpose, being "to remove overburden to give access to any
mineral", for Mining Purposes Lease 24 (Act 1973) held in the
name of Mount Carrington Mines Limited; and c) grant leases, in
satisfaction of Mining Lease Applications 598, 628, 629
(Inverell) and 247-254 (inclusive) , 264, 273, 274 and 271
(Tenterfield) , to Mount Carrington Mines Limited pursuant to
Section 53(2) of the Mining Act, 1973, subject to the conditions
to be attached thereto.
r'ut'rrir V
Existing Lease Term Minerals
ML 5883 (Act 1906) 10 yrs silver, lead, zinc, gold, copper
SL 409 (Act 1906) 20 yrs gold, silver
Lease Application
MLA's 247-254 (inclusive) 264, 273, 274 and 277 (Tenterfield)
MLA 598 (Inverell)
MLA 628 (Inverell)
MLA 629 (Inverell)
MPL 24 (Act 1973) 21 yrs
Lease to be Granted (Act 1973) Term
ML 1147 until 14/12/97
ML 1148
10 yrs
ML 1149
10 yrs
ML 1150
10 yrs
arsenical pyrites silver, lead, zinc copper, bismuth, sulphur, gold
copper, silver, tin, lead, zinc, gold, galena, bismuth
copper, lead, zinc silver, gold
copper, lead, zinc silver, gold
Dated this twenty seventh day of November, 1985.
Peter Cox
Minister for Mineral Resources and Energy.
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GS 1984/340
1.0 INTRODUCTION
In 1980 a joint venture was formed between Aberfoyle Exploration
Pty Ltd (60%) and Mount Carrington Mines Ltd (40%) , to explore
and develop several prospects around Drake, a small town in
northern New South Wales, about 70 km west of Casino. The N.S.W.
Government approval for the Joint Venture was given by the
Minister for Mineral Resources on 21st October 1980. This
approval was limited to specified mineral tenement authorities
held by the Joint Venture. The approval did not permit mining
operations. These may only be commenced upon compliance with a
schedule of conditions which was issued at the time of the
approval (which in effect require the preparation of an EIS for
any new proposed mining development), and with the approval of
the Minister.
After investigating several of the Drake mineral deposits (White
Rock, Red Rock, Silver King and Lady Hampden), the Lady Hampden
orebody was chosen as the most economically feasible to develop.
The location of the project area is shown on figure 1. The
proposal is to redevelop one of the nineteen mineral deposits
that have been found and worked within a few kilometres of Drake.
The gold, silver and copper mineralization around Drake has been
intermittently worked over the past 90 years.
To 1984, a total resource of 3.4 million tonnes of ore has been determined within the Lady Hampden, Silver King, White Rock and
Red Rock mining leases, of which it is now proposed to mine 1.5
million tonnes from Lady Hampden. 1.0 million tonnes of ore will
be obtained by extending a small existing open cut established by
Mount Carrington Mines in 1976, and possibly a further 0.5
million tonnes by underground methods if future economics
indicate that to be the most viable approach.
A treatment plant will be erected with an annual throughput of
250,000 tonnes (33 tonnes per hour) . The ore will be crushed,
ground and a flotation concentrate produced. This will then be
leached with sodium cyanide in agitator tanks, a gold/silver
precipitate prepared, and then melted to bullion.
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The proposed development falls under Part V of the Environmental
Planning and Assessment Act 1979 (New South Wales) because there
is no local planning instrument currently in force in Tenterfield
Shire, and is an "activity" for which the Minister for Mineral
Resources is the "determining authority". The Minister for
Mineral Resources required that an Environmental Impact Statement
be submitted, pursuant to Section 112 of the EPA Act.
Systematic environmental work for the project was undertaken in
1981 at the time of commencement of exploratory drilling, with
the intention of providing baseline information for the major
potential environmental issues.
The results of these investigations appeared in the 1981 study
"Preliminary Environmental Survey, Drake Prospect, N,S.W."
(N.S.R. Pty. Ltd). Additional water quality work was undertaken
during 1983 and detailed examination of environmental factors
relevant to the proposed operation was carried out in early 1984,
by the proponent and their consultants, (Natural Systems Research
Pty Ltd with Maunsell and Partners and Stuart Miller and
Associates).
A draft copy of the E.I.S. was submitted to this Department in
April, 1984, and the amended final document was subsequently
placed on public display on the 28th June 1984 (See Appendix 1),
During the course of the exhibition period, technical officers
from the Department inspected the site of the proposed operation.
Copies of all submissions received were forwarded to Mount
Carrington Mines Ltd in order that they could respond to matters
of concern.
In September 1984 Aberfoyle Ltd withdrew from the joint venture
under an arrangement whereby Mount Carrington Mines Ltd bought
Aberfoyle's stake in the project, giving it outright ownership of
the project.
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GS 1984/340
This Assessment Report summarises the components of the
proposal, and contains an examination of the EIS and all
submissions received. Changes to the original EIS required by
the Department of Mineral Resources in the light of submissions
received are annoted in the text as applicable.
The conclusions and recommendations of the Department of Mineral
Resources, based on its assessment of the proposal, are stated in
Chapter 7 and these have comprised the Department's advice to the
Minister for his final determination of the proposal.
Chapters 2, 3, 5 and 6 are based on the original EIS. While this
assessment report is intended to be able to "stand alone", a
considerable amount of additional detail can be obtained from the
E.I.S.
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GS 1984/340
2.0 PROJECT DESCRIPTION
2.1 Geology and Resources
The geology of the Lady Hampden area consists of a layered
sequence of volcanoclastic rocks, known as the Drake Volcanics.
They are mid-Permian in age, with intrusions of dacitic,
andesitic and diabasic composition. The vo1anoclastics and
intrusives are cut by a number of north-east to north-west
striking, steeply dipping faults (dipping about 70° to the east)
some of which have considerable vertical movement.
The fol]owing geological resources have been determined by the
proponent:
MillIon Grade gm/t
Tonnes Silver Gold
Lady Hampden Indicated 1.0 80 1.0 Inferred 0.5 92 0.6
Silver King
Inferred 0.3 144 0.2
The Lady Hampden indicated resource has been percussion drilled
to a 15 m x 15 m pattern.
The mineralisation occurs as three main styles:
Discrete veins or lodes Vein stockworks Suiphide disseminations
5 GS 1984/340
The stockwork and disseminated styles are characterised by low
temperature, epigenetic silver-gold-basemetal-pyrite mineral!- - sation and silicate walirock alteration.
- The major precious metal-bearing phases are gold-rich electrum
and silver-rich suiphosalts.
2.2 The Project Proposal
The proposed layout for mining and treatment operations at Lady
Hampden mine is illustrated in Figure 2.
a) Mining
The proposal is based on mining 1.5 million tonnes of ore from
the Lady Hampden ore body over a 6 year period. Of this, an
initial 1.0 million tonnes of ore will be mined by open cut
methods (which will additionally involve approximately 1.3
million tonnes of overburden and waste removal, and the stock
piling of 1.0 million tonnes of low grade material for possible
future treatment). The remaining 0.5 million tonnes of ore may
be mined by underground methods, although the economics of
alternative methods will be reviewed after the first few years of
the project. Figure 3 illustrates the proposed final pit limits
in cross section.
The surface area of the open pit will be approximately 4.5
hectares, maximum length 260 metres, maximum width 180 metres,
maximum depth 70 metres. The overall slope of the pitwalls is
expected to be typically 501 -with local flattening for haulroads
and near the surface in overburden material. Final benches will
be 15 metres high and 10 metres wide.
Clearing and Topsoil Removal:
Trees, shrubs and other undergrowth will be cleared, and re-
usable topsoil removed and stockpiled for use during
rehabilitation operations.
6 GS 1984/340
Overburden, Waste & Low Grade Ore Removal:
During opencut mining an average of 3000 tonnes per day of waste
and low grade ore will be removed on a 5 day per week basis.
Drilling and blasting will be used where necessary to supplement
ripping; material will be loaded onto off-highway dump trucks by
front-end loader and hauled to the waste dump and low grade
stockpile areas to be established north of the pit.
Ore Removal:
Ore will be percussion drilled, and blasted using ammonium
nitrate based explosives. The blasting pattern will tend towards
close-spaced small diameter holes to facilitate ore and waste
segregation and to minimise throw, flyrock, and secondary
breaking requirements. Benches will be mined at 7.5 metre height
to further aid in ore and waste segregation with completed
benches at 15 metre intervals and 10 to 15 metres wide. Off-
highway trucks of approximately 35 tonne capacity will be loaded
by front-end loader and will deliver high grade ore to the mill
stockpile at a rate of 1000 tonnes per day, five days per week,
between 7am and 5pm,in addition to the 3000 tonnes of other
material mentioned above.
b) Ore Treatment
Throughput Rate:
The plant will have a design capacity of 250,000 tonnes of ore
per annum (715 tonnes per day for 350 days per annum) . Figure 4
shows the simplified flowsheet.
Crushing:
Ore from the mill feed stockpile will be fed to a primary jaw
crusher by front-end loader for approximately 3 hours per day,
for 6 days per week between 7am and 5pm. Dust will be controlled
at this point by the application of fine water sprays. Crushed
ore will be conveyed to a 3,200 tonne live capacity stockpile.
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GS 1984/340
Grinding:
Grinding, together with flotation and leaching will be a
- continuous process, 24 hours per day for 350 days per year.
A conveyor from the crushed ore stockpile will feed ore at 33
tonnes per hour to a 4.3 m diameter by 1.8 m long semi-autogenous
grinding mill of 427 kW. This mill will be followed by a 2.1 m
diameter by 3.7 m long ball mill of 300 kilowatts. The slurry
will then be pumped to the cyanide leaching circuit.
Cyanide Leaching:
The slurry from the ball mill will be pumped to a group of three
agitation tanks in series. These tanks are of steel construction
approximately 15 metres high and 6 metres diameter. The slurry
is agitated mechanically and with air in the presence of lime.
This slurry will then be passed over a belt filter to form a cake
with 20% moisture. The filtrate is used later in the circuit to
slurry the tailings filter cake for pumping to the tailings area.
The filter cake will be re-slurried with "barren" solution from
the Merrill-Crowe metal extraction circuit (see below), and a
weak (2 gm per litre) sodium cyanide solution is formed to leach
most of the gold and silver in a further six agitation tanks
similar to above.
This slurry will then be passed over another belt filter with the
filter cake being re-slurried and pumped to tailings as described
above. The filtrate "pregnant solution" is fed to the Merrill-
Crowe metal extraction plant.
Reagents:
Reagents used in the leaching stage will be:
Ff GS 1984/340
Addition Rate kg/tonne of mill feed
Annual Consumption (tonnes)
Cyanidation
Sodium Cyanide Lime Zinc dust
2.0 10.0 0.07
500 2,500 17.5
II Thickening
Flocculant (polyacrylamide)
0.01
2.5
Extraction of Metal from Pregnant Solution:
The silver and gold will be extracted from this solution by a
conventional method known as the Merrill-Crowe process. The
solution is filtered, de-aerated by a vacuum pump and tower, and
zinc dust is then added (0.07 kg/t) to precipitate the silver and
gold as a black powder, which is collected in a filter. The
filtrate is returned to the cyanide leaching circuit, thus re-
cycling the cyanide, whilst the filter cake is removed to a
furnace for melting into crude gold/silver bullion. The bullion
is poured into bars which are sold to a refinery.
Storage of Reagents:
Sodium Cyanide; a maximum of 50 tonnes will be held on site in
100 kg steel drums. The drums will be stored undercover and
fenced in clearly designated cyanide-poison areas. Drums will be
stored on pallets, eight drums to a pallet (two layers of four).
Drums will be delivered to a reagent mixing area and emptied into
a stirred tank. Protective clothing, gloves, goggles and dust
respirator will be worn during the handling of drums. Empty drums
will be washed out with sodium hypochlorite or an equivalent.
All cyanide areas will be clearly marked and appropriate safety
precautions taken. All contaminated drainage water areas will be
directed towards the stockpile leachate dam. Quantities of
sodium hypochlorite will be available for spills.
9 GS 1984/340
Lime; up to 75 tonnes of slaked lime will be held on site. The
lime will be stored in a bulk bin and conveyed to the ball mill
at a regulated rate. Protective clothing, gloves and face mask
will be worn whilst working on lime storage areas.
Flocculant; up to 30 bags, each 25 kg, will be held on site.
The bags will be stored on pallets undercover. The flocculant
will be mixed in a proprietary mixer to produce a 0.05% solution.
All spills and slippery areas will be covered with sand before
removal to the tailings area.
Zinc Dust; approximately 750 kg of zinc dust will be stored on
site in drums.
c) Tailings Disposal
The tailings will consist of the filter cake from the belt filter
on the cyanide leaching circuit. Virtually all cyanide is washed
from the tailings, as the cyanide contains the dissolved silver
and gold. The tailings will be disposed of by the "thickened
discharge method", whereby the thickened slurry is pumped to a
cleared area and forms a conical hill of 6% slope, eventually
reaching 14 metres in height and approximately 500 metres in
diameter (at an insitu specific gravity of 1.8). Run-off
catchment bunds are formed around the perimeter, and the run-off
is then returned to the first grinding mill as process water.
Physical and Chemical Properties of Tailings:
The tailings solids quantity is 715 t.p.d. (at a specific gravity
of 2.7) for 350 days per year for an annual total of 250,000
tonnes.
Tailings emerge from the leach process as a cake and are slurried
by the addition of approximately 0.7 Ml per day of water for 350
days per year for an annual total of 240 Ml.
The metal content of the slurry make-up water averages 8.5 mg/l
copper and 3 mg/l zinc, with nickel, iron, lead, arsenic,
antimony, manganese and cadmium less than 1 mg/l.
10 GS 1984/340
2.3 Infrastructure and Ancillary Services
a) Electricity Supply -
The Northern Rivers County Council advise that the existing -
supply to Drake township (2.5 km from the mine site) would
require upgrading to provide an adequate supply and that this
could be done with a capital contribution from the proponent.
The estimated energy requirement is 15,000 kilowatt hours per
day, 350 days per year.
b) Water Supply
By containing all run-off from tailings and waste rock areas,
together with mine dewatering, it is expected that sufficient
water will be available for the milling process. Potable water
would be pumped from Sawpit Gully Creek. Initial mine water for
start-up will be taken from the existing pit, and also Sawpit
Creek if necessary.
C) Roads
Access to the site is by an existing public road from the Bruxner
Highway. As the existing public road passes through the mining
area, a new road will be constructed to the west for a distance
of approximately 2 km. Tree cover will be maintained for
sufficient distance to completely screen the operations from the
relocated road. Construction of the road has been discussed with
the Shire Council, and it has been agreed that it be rebuilt to a
similar standard as before, in accordance with Shire
requirements.
d) Buildings
It is anticipated the following buildings will be provided:-
6 Transportable office buildings
Transportable laboratory
2 Transportable change/washrooms
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GS 1984/340
Workshop
Warehouse
Process/reagent building
Silver/gold room
e) Sanitation
Septic tank systems will be provided, subject to approvals from
the Health Inspector of Tenterfield Shire Council.
2.4 Employment
a) Construction Workforce
Site construction will be carried out by sub-contractors from the
surrounding districts as much as possible. Site employees will
range from 10 to 40 for the construction duration.
b) Operations Workforce
Mining will be carried out by a contractor under the direction of
Mount Carrington Mines. The contractor would employ
approximately 15 persons, including supervisors.
All other personnel will be employed by Mount Carrington Mines
and would total approximately 55.
c) Recruitment and Domicile
The mining contractor will make his own accommodation
arrangements for key imported personnel and will recruit others
living within the Drake/Tenterfield district.
Employees will be recruited where possible from the
Drake/Tenterfield area. The existing project accommodation at
Drake will be expanded to accommodate approximately 35 single
- persons (currently 15) . Accommodation and messing will be
provided on a "living-away-from-home" basis for 3 or 4 nights per
- week, rather than permanent residence. Employees would then
return to their homes in towns such as Tenterfield and Casino.
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GS 1984/340
The operations would be a substantial employer in a district
which has experienced declining employment opportunities.
2.5 Environmental Management
a) Water Management Scheme
The water management scheme is based on a number of management
principles designed to control water discharge from the site
whilst at the same time providing the necessary quantity of water
required for ore treatment.
The process water is to be maintained within a closed water
system and sediment dams around stockpiles and other disturbed
areas will prevent off-site discharge of sediments.
Stream diversions will avoid changes to the natural water system
wherever possible, and runoff from disturbed areas will be
diverted away from the site to prevent contamination. Adequate
water for ore treatment plant consumption, dust control
requirements and potable water supplies will be provided by
storages. Initial water for mine start-up will be provided by
the existing mine pit, and also Sawpit Creek if necessary.
The water system consists of two major parts (see Figure 6)
The primary system is a closed circuit designed to provide water
for the ore treatment plant, and includes control of run-off and
leachate from ore stockpiles and high to medium grade waste ore
stockpiles. The secondary system controls sediment and run-off
from waste and low grade waste ore stockpile areas and other
disturbed areas on the site, and also diverts clean water run-off
away from the mine area.
b)Solid Waste Management and Rehabilitation Schemes
Waste management and rehabilitation at Lady Hampden will aim
firstly to rectify the past mismanagement of waste from the old
open cut. Secondly, the new mining operation will be planned to
contain all disturbance to the Sawpit Creek catchment, and to
r
13 GS 1984/340
selectively site wastes so as to minimise the generation of
contaminated drainage and avoid surface soil contamination.
Rehabilitation works will aim to stabilise wastes, control
erosion and promote revegetation.
Solid wastes include almost the whole of the ore throughput to
the mine, as only a small fraction is actually metal. Wastes
include weathered rock, fresh rock and solids from the tailings
disposal system. These will be divided into dumps of various
grades according to their potential for future processing. Dumps
will be constructed so that the outer surface is formed of non-
acid waste to aid revegetation if they are notre-processed. The
tailings will form a conical hill approximately 14m high and 500
metres in diameter, which will be a stable landform suitable for
revegetation once covered with soil.
On completion of mining, there are a number of options for use of
the pit, including filling it with tailings then re-contouring
and revegetating it, or leaving it open (with suitable fencing,
drainage and contouring) for future ore access
The objects of the rehabilitation programme will be to stabilise
the land, minimise erosion and return the land to a forested
system. Waste dumps may require reshaping before topsoiling,
although the tailings dump will probably not require re-shaping.
Detailed planning and implementation of erosion and drainage
controls and the revegetation program will be developed in
corsultation with the Department of Mineral Resources, Soil
Conservation Service and Forestry Commission.
c) Environmental Safeguards
Safeguards and controls to minimise contamination of the
environment include the following:
(a) Sediment retention dams to remove suspended matter from
- water prior to being released from site.
14 GS 1984/340
Diversion channels to separate clean and contaminated types
of run-off and to direct selected types off-site.
An emergency storage will be provided by using the mine pit
in the case of spiliway discharge of the stockpile leachate
dam which holds the process water.
Diversion channels will be constructed to the same cross-
section as the original channel and scour protection
provided if necessary.
A monitoring programme will be established for early
detection and control of contamination during mining and/or
processing operations.
Monitoring of surface and groundwater will be carried out to
assess the effectiveness of the adopted water and solid waste
management strategies and to determine the need for an
alternative approach if necessary. Similarly, monitoring of
catchment water quality will be ändertaken at selected sites both
upstream and downstream of the mine site. The fact that all
wastes will be placed in the one catchment (Sawpit Creek) will
enable a simple water monitoring network to quickly locate any
potential hazards.
The major hazard from rock weathering is the production of acid
mine drainage and acid waste. A monitoring program will be
implemented (along with ore grade testing) to determine the acid
potential and dumping requirement of each block prior to
excavation from the mine pit. Rehabilitation will be carried out
progressively on the rock dumps and tailings, and will include
ongoing monitoring and management to assess revegetation success
and to contain and repair eroded areas.
15
GS 1984/340
3.0 EXISTING ENVIRONMENT
3.1 Climate
Drake lies on the eastern slopes of the New England Range in
northeastern New South Wales, midway between Tenterfield and
Casino. The climate is cool subtropical, with average rainfall
of 1054 mm and a distinct wetter season from December to April.
The average summer maximum temperature is 30°C and winter 20°C.
Rainfall at Drake Post Office has been recorded continuously for
91 years since observations were first documented in 1891. The
annual mean rainfall is 1054mm, with a maximum in summer (January
and February averaging more than 150mm) and a minimum in spring
(August and September averaging less than 45mm). Raindays
average 100 each year, decreasing from 12 in January and February
to 5 in July and August.
The driest year on record has been 1915, when only 420mm fell
40% of the mean. The wettest year has been 1893, when the total
was 1968mm - 187% of the annual average. The greatest daily and
monthly rainfall was also in 1893, in February, with totals of
210mm and 898mm respectively.
Rainfall intensity probabilities for Drake have been computed by
the Bureau of Meteorology. Table 3.1 presents predicted maximum
rainfalls for various durations and return periods. The highest
daily rainfall recorded at Drake in 91 years, 210mm, is in good
agreement with the 24-hour rainfall prediction in this table for
a recurrence interval of 100 years, 204mm.
TABLE 3.1 Maximum Rainfall Predictions for Drake
Return TOTAL RAINFALL (mm) Period 0.1hr. lhr. 12hrs. 24hrs. 48hrs. 72hrs. 1 year 8 26 56 72 96 110 2 years 10 33 72 93 124 145 5 years 13 41 92 120 159 184
10 years 15 47 106 137 180 207 20 years 16 53 121 157 207 237 50 years 19 61 140 183 240 276
100 years 21 67 156 204 267 307
16 GS 1984/340
3.2 Drainage and Water Quality
The project area is drained by headwaters of tributaries of the
Clarence River, whose 22,700 km 2 catchment forms the largest
drainage basin in the north coast area of N.S.W. (figure 5)
The overall drainage pattern around Drake consists of dendritic
small streams flowing northeast. The Lady Hampden area and Drake
township are situated within the Plumbago Creek catchment, which
joins with the main Clarence River catchment. The Lady Hampden
mine is located on Sawpit Creek, a small stream which enters
Plumbago Creek approximately 5km downstream from Drake township.
The Mt. Carrington area (disused) is located in the upper
headwaters of Sawpit Creek, and other abandoned mines are
scattered throughout most of the Plumbago catchment upstream of
its confluence with Sawpit Creek. Drake township is located at
the confluence of Plumbago Creek and Fairfield Creek, with the
town water supply coming from Fairfield Creek.
The water quality investigations around Drake concentrated on the
characteristic pollution by uncontrolled leachate and runoff from
sulphide orebodies, that is, with emphasis on pH, sulphate, TSS
and selected heavy metals. The results substantiate the findings
of a June 1980 Department of Mineral Resources study and show the
following:
High concentrations of metals immediately downstream of
Lady Hampden (Cu,Zn,As,Pb,Cd) and White Rock (Zn).
The evidence suggests rapid improvement with increasing
distance downstream.
Low diversity of aquatic invertebrates is qualitatively
correlated with high heavy metals in water, and these are
both, in turn, correlated qualitatively with proximity to
areas of past mining.
17
GS 1984/340
3.3 Soils
The mine site and immediate surrounds are located within
undulating to hilly valley slopes with small terraced alluvials
adjacent to the creek lines. A total of six soil types were
identified.
a) Description of Soil Types
Solodics and Soloths -
These soils are the most commonly occurring type within the
proposed operations area.
Yellow and Brown Earths -
These soils tend to occur adjacent to Sawpit Creek on relatively
flat areas. Flooding of the Creek rarely reaches a height which
floods water over these soils.
Prairie Soils -
Only a small section of Prairie Soil was found but they may be
- more extensive. The essential feature of this soil is a thick
dark A horizon with medium structure and friable moist
consistency.
Undifferentiated Alluvials and Creek Bed -
Although no profiles of these soils were examined in the field
minor occurrences were evident following initial site
reconnaissance and aerial photo interpretation. Because of the
delicate nature of the ecosystem within which these soils occur
these areas should not be disturbed. The undifferentiated
alluvials essentially consist of layered materials which are
variable and highly erodible when disturbed.
b) Erosion Potential of Soils
Currently all the soils on the site are stable with the only
- significant erosion occurring on cleared areas and on the outside
of meander bends on the creeks.
18 GS 1984/340
All the soils are susceptible to erosion once the protective
vegetation cover is destroyed. Particular care needs to be taken
with soil horizons which are low in organic content. These
horizons tend to be any colour other than brown or black.
Appropriate rehabilitation procedures and erosion controls should
prevent excessive erosion from the site and in the longer term,
control erosion to pre-mining rates (geological rates).
3.4 Vegetation
The mine area and surrounds are classified as Dry Scierophyll
Forest (Eucalyptus maculata - E. paniculata)
Understorey species include Xanthorrhoea sp. and grasses such as
Themeda austr1is. Cymbopogon refractus, Panicum simile and
Sorghum leiocladum. Zornia dyctiocarpa, Glycine clandestina,
Desmodium brachypodium and Helichrysum apiculatum are also
common.
Associated tree species include Eucalyptus eugenoides, E.
gummifera, E. punctata, E. paniculata, Angophora floribunda and
Casuarina torulosa.
3.5 Fauna
a) Terrestrial Surveys
The vertebrate fauna were surveyed by observation, literature
review, and discussion with employees at the Aberfoyle camp,
local naturalists and research biologists familiar with the area.
An unusually high diversity of species of birds, mammals and
reptiles exists in the regional area because it is a transition
zone between the coast and tablelands and includes components of
both ecosystem types, as well as being central in the north-south
ecological gradient.
Systematic studies of the areats herpetofauna have not been
carried out but discussions with herpetologists suggest that the
occurrence of any rare, endangered or locally restricted species
is unlikely.
19 GS 1984/340
Bird records for the area can be considered reasonably complete.
Present and past land uses have had little effect on the
naturally high species diversity and any future mining and
forestry operations would also have little effect, particularly
compared to land clearing for pastoral use and settlement. There
are no mammal species occurring in the study area which have
particularly restricted ranges.
b) Stream Surveys
A qualitative sampling of the study area streams was carried out,
by net and subsequent identification, at sixteen selected sites.
While the survey was carried out in low-flow streams after a
prolonged drought, aquatic biota indicated a clear pattern of
water quality.
The most prominent feature is a low species diversity of aquatic
biota downstream of the old mines at both Lady Flampden and White
- Rock. There is a strong correlation with water runoff from the
old waste rock dumps, which is turbid, acidic and carrying heavy
- metal concentrations. Forestry and pastoral activities, and
runoff from Drake township, are not apparently correlated with
reduced diversity of aquatic invertebrates in the study area.
Downstream of the old mining areas, the diversity of
invertebrates is restored, indicating a return to satisfactory
water quality.
3.6 Aboriginal Archaeology
Surveys, discussions with local residents including Aborigines,
and published archaeological and ethnohistorical data indicate
that sites are likely to occur infrequently in the study area and
that any sites would have been disturbed by past logging and
mining activities and/or be obscured by forest litter.
- Aboriginal use of the tract of country encompassing the study
area was probably transitory.
20 GS 1984/340
This, combined with the lack of suitable rock outcrops which
could have acted as foci for prehistoric activity, poor surface
exposure and landscape disturbance, can account for the lack of
archaeological evidence and paucity of sites, and it is unlikely
that information of archaeological importance would be recovered
by further surveys in the study area.
3.7 Land Use
The project area lies within the Girard State Forest, under the
administration of the Forestry Commission of New South Wales.
The Forest produces logs for sawmilling and there is a sawmill at
Drake.
The small settlement of Drake village is 2.5 kilometres from the
Lady Hampden project area, but lies at the centre of the much
larger Drake mining field and is surrounded by areas of
traditional prospecting and mining interest.
Farming, largely beef cattle grazing, is now the principal land
use in the district along with timber production.
Unemployment is regarded as high in this part of Tenterfield
Shire.
The Bruxrier Highway, a main road from the coast at Grafton to New
England at Tenterfield, passes through Drake 2 kilometres from
the project area but the site is not visible from the Highway.
3.8 Existing Noise Levels
The background noise level was measured at 1935 hours on 1 June
1984 at the boundary of the nearest affected residence, being at
the junction of Cheviot Hills Road and the Bruxner Highway. The
level was established as 32dB(A) (measured in decibels on the A
scale weighting network, which is designed to simulate human ear
response) .
The climatic conditions at the time were as follows:- Dry Bulb
temperature 13°C, Wet Bulb temperature 11.5°C, Relative Humidity
85%, Bar Pressure 1024 mb, Wind nil, and Cloud nil.
21
GS 1984/340
4.0 REVIEW OF SUBMISSIONS
4.1 Members of Public
No submissions were received.
4.2 Local Government
No -submissions were received.
4.3 Government Authorities
Submissions were made by the following authorities:
- Mines Inspection Division, Department
of Industrial Relations
- State Pollution Control Commission
- Forestry Commission of NSW
- Soil Conservation Service of NSW
- Water Resources Commission
- Public Works Department
- Crown Lands Office
The National Parks and Wildlife Service sent an interim reply,
not subsequently followed by a submission.
Copies of all submissions were forwarded to the Department of
Environment and Planning on the 23rd August, 1984. The
submissions were also forwarded to Mount Carrington Mines Ltd in
order that they could make appropriate responses or conduct
further investigations as applicable.
The submissions are discussed individually below. Comment by the
the Department of Mineral Resources (in some cases using
information supplied by the proponent) is annotated.
22
GS 1984/340
Mines Inspection Division, DIR
No objections, and noted they would conduct regular inspections -
of any operations to ensure activities complied with the Mines
Inspection Act, 1901.
Public Works Department
With specific regard to the Tabulum Aboriginal Reserve water
supply, it was noted that any discharges upstream (into Plumbago
Creek) of the intake should desirably conform to Class P standard
and not be less than Class C standard under the Clean Waters Act.
Corrnient:
In the future water quality in Plumbago Creek will be able to be
directly monitored and compared to the established baseline
information. Legislative provisions of the Clean Waters Act are
such that compliance can be enforced.
For existing conditions, with uncontrolled pollution from old
mine workings at Lady Hampden and White Rock, the surveys of
downstream water quality and aquatic ecology show a return to
good quality water at Site W19, on the Plumbago Creek some 5 km
upstream from the Tabulam Aboriginal Reserve. During mine
operation, there is a reasonable case for suggesting the existing
situation will not be worsened, taking into account that the
existing pollution sources around Lady Hampden will be
controlled. If undiluted tailings slurry water were pumped out
during a high intensity rainstorm (1:10 year) then the dilution
factor at site W19 (assuming even rainfall across the catchment),
would be approximately 1:1000. The effect of this is shown in
the table below:
23
GS 1984/340
Table 4.1
Dilution Factors
Cu Zn Ni Fe Pb As Sb Mn Cd
Tailings Water 8.5 3.0 - less than 1.0 T.W. Dilution at W19 0.0085 0.003 - less than 0.001 - Highest Rec. at W19 0.073 0.072 - 1.7 0.042 0.01 - 34.0 0.0028
Class C stds 1.0 5.0 - 0.3*0.05 0.05 - 0.05*0.01
(Values are in mg/i)
* filterable
Additional dilution would also have occurred in the tailings
impoundment, and the adoption of tailings slurry water values is
conservative. Using the 1 in 20 year retention criteria now
required by the Department of Mineral Resources for the hiclosedu
system, hypothetical pollution would be correspondingly less than
above.
State Pollution Control Commission
Having regard to the conditions which can be imposed under the
legislation which the Commission administers, the Commission
considered there to be no reason on the grounds of air, water or
noise pollution to withhold development consent. Specifically,
the Commission noted the following:
Water Pollution:
The Commission's approval under Section 19 of the Clean Waters
Act will be required for water pollution control works. An
extensive sampling operation has been carried out in the area.
This has indicated present environmental levels of Zn, Cu, Pb, Cd
and As are high, largely as a result of weathering or erosion of
old mine sites. The argument that the proposal will lower the
contribution of the above metals to the local watercourses is
agreed with by the Commission.
The Commission noted that further information on the waste
products potential to produce acid wastes, and the disposal of
tailings would be required.
24 GS 1984/340
Corrinent:
This is an area that requires careful monitoring after production
commences, but it is considered that further work cannot be
carried out until the material in question is available from
mining operations. Based on current knowledge, all reasonable
precautions have been planned for waste disposal.
In regard to air and noise pollution the operation will require
the Commission's approval in accordance with Section 16 of the
Clean Air Act and Section 27 of the Noise Control Act.
Soil Conservation Service
The Service conducted a site inspection in association with their
EIS review. The Service considered the EIS to be comprehensive
and accurate and did not raise any objection to the proposal.
Recommendations were made that all engineering structures be
designed using a 1 in 20 storm occurrence instead of 1 in 10
years as used, and that any diversion channels be designed
according to Service specifications.
Coninent:
1:20 storm occurrence design criterion suggested is considered
appropriate for the tailings dam and Clean Water Dam No. 1
Leachate Dam system.
The design of diversion channels are to follow the guidelines in
Section 3.2 of the SCS Technical handbook No. 2 - Urban Erosion
and Sediment Control.
Crown Lands Office
It was assessed that the statement adequately considers the
impacts of the proposal. Some specific matters were raised.
(i) Details of the design and materials to be used in
construction of bunds and dam walls.
25 GS 1984/340
Connie n t:
- Sufficient detail is supplied for general assessment - an EIS
cannot contain detailed engineering design of all facets of the
- project. Detailed design work will be part of the next phase of
the project, and will follow the principles laid down in this
Assessment Report and the guidelines and regulations of the
relevant authorities.
Method of return of run-off water from tailings dump to
mill for process water.
Cormier&t:
Run-off from the tailings area will be collected in a sump within
the enclosed tailings area and pumped to the mill area via a
pipeline. There would thus be no problems with contamination
during the crossing of Sawpit Creek, unless in the unlikely event
of the pipeline fracturing.
Treatment process for waste and contaminants, particularly
- the leachate dam, after completion of operations.
Coninent:
Treatment of the leachate dam water will depend on the actual
water quality. The current indications are that the
contamination level will be amenable to treatment by lime, or
discharge into the final void. Leachate dam solids would require
placement in the final void at the completion of mining
Waste rock will be monitored and the most toxic units buried as
described elsewhere.
The major part of the solid waste management program (EIS Section
6.2) comprises day-to-day procedures that will ensure that the
area at the conclusion of operations is physically and chemically
amenable to final stabilisation and revegetation. These measures
specifically deal with the treatment of waste and ore, and are
reported in the EIS.
26 GS 1984/340
Further details will be developed in consultation with the SPCC
during licensing procedures, and again during operation with the
SPCC, Forestry Commission, Water Resources Commission and Soil
Conservation Service when completed waste emplacements come up
for final abandonment planning. This will require data from the
operation itself not available at present, and for this reason,
final plans cannot be drawn up now.
The final pit will be similar to the present void, but larger.
It will have no surface water catchment, the water level will, as
at present, be that of the water table, and no surface water
discharges will occur.
Sawpit Gully Ecology
Corrrnertt:
The ecology study reported in the EIS revealed a grossly degraded
ecosystem in Sawpit Creek, but a return to normal water quality
and benthic invertebrates by Site W19, 20 km downstream on
Plumbago Creek.
Sawpit Creek is 3 km long and is not considered worthy of
conservation efforts per Se. The emphasis of the mine waste and
water management strategy has been to structure the hydrology of
Sawpit Creek so as to contain present and future sources of
pollution, and control mine area drainage, for the benefit of the
downstream drainage. In any event, Clean Water Dam No. 2 will
probably release water during much of the year.
Visual management objectives.
Conment:
A visual assessment was not carried out as part of the EIS for
four reasons:
-
the final appearance of the area after cessation of mining
will be of a vegetated, largely treed landscape - an
improvement on the bare mullock heaps present today.
27
GS 1984/340
-. The area is a very small part of largely similar country,
and is not visually outstanding in this context.
- The area is not frequented by tourists at present, nor is
it likely to be, given the many outstanding natural
features in this part of New South Wales generally.
- The area is not visible from the Bruxner Highway, or from
any residences.
It is considered sufficient for land management proposals to
offer a visually similar landscape at the conclusion of mining.
(vi) The issue of monitoring the proposed operation.
Convien t:
Monitoring proposals are given in the EIS. These are for the
preliminary consideration of Government Authorities and can be
refined for licensing purposes and the Environmental Management
Plan.
Forestry Commission of NSW
The Commission has no objections in principle to the proposed
operation, but stressed a number of areas where full consultation
should occur with the Commission during the proposed operations.
The Commission noted that the area where the proposed mine is
located is part of Girard State Forest, and some 35 ha will be
taken out of forestry production for the duration of the
operation.
At the conclusion of mining, the Commission will resume
management responsibility for the whole area including the open
pit and waste stockpiles, after satisfactory rehabilitation has
been undertaken.
This part of Girard State Forest is covered by an Occupation
Permit for grazing issued by the Forestry Commission. The
Occupation Permit area is fenced and there will be a need to
GS 1984/340
exclude stock from the area of the proposed mining operations.
Fencing of the operations was recommended.
The Commission has the view that at the completion of the open
cut mining the open cut should be filled with tailings, thus
reducing the tailings dump size and leading to a better overall
rehabilitation of the site.
Waste water handling was also of concern to the Commission. They
note that various monitoring programmes are to be established to
assess the effectiveness of the water and solid waste management
strategies and to determine the need for alternative approaches,
if necessary, but express concern as to responsibility.
It was also noted that the tailings dam area at maximum capacity
was shown as extending into part of the Girard State Forest not
covered by mining leases or applications.
Corrment:
The Commissions comments on the EIS are noted, and in particular
their responsibilities for the area at the conclusion of mining
and the need for consultation on matters relating to its future
use.
Commission officers (from the District office) have been of
technical assistance to the field investigations leading to the
EIS and liaison in detail will be required when the following
matters are addressed:
- Fencing
- Rehabilitation
- Revegetation planning and monitoring - Road relocation
The return of tailings from stockpiled low grade ore into the pit
is an option requiring evaluation if it becomes economic to
process this low grade ore. This will not be known for some
years.
29 GS 1984/340
Water management strategy is outlined in the EIS (and modified in
this Assessment Report) and detailed licensing requirements will
be addressed by the SPCC. Monitoring conditions and
responsibilities will be controlled by the Department of Mineral
Resources and the SPCC.
In regard to the tailings dam coverage, the proponent has
submitted MPLA 643 (Inverell) for the area concerned.
Water Resources Commission
The Commission suggested more attention to detailed assessment of
the impacs was required, as well as site management,
environmental safeguards and contingency plans. Specific matters
are listed below.
(a) Dams - capacity calculations
- proposed dams be provided with spiliways to
accommodate 1 in 100 years flood
- sediment dams be redesigned to 1 in 10 years
rainfall return period
COnlnefl t:
It is appreciated that the Rational Method is not commonly used
to size capacities of small dams, but it is a time efficient
method to calculate approximate flood volumes and is considered
appropriate in this initial review case. A time of concentration
rainfall approach would be more appropriate for final design
purposes.
Whilst it is agreed that spillway provisions have not been
presented, they are inferred in the document. Such provisions
were expected to be part of any detailed design work required at
some later date.
The spillway criterion of 1 in 100 years rainfall will be
required for the clean water dam No. 1, the leachate dam, and the
tailings dam. Major spillways are not required on the sediment
dams.
GS 1984/340
A retention design criteria of a 1 in 5 year return for sediment
dams is considered appropriate as they should not contain toxic
wastes and are relatively minor structures.
Diversion Channel - should be redesigned so as to handle
floods of return periods greater than 1 in 5 years, or the
mine pit protected by a levee against filling by channel
ovef low.
Corrtnent:
The provision of a levee bank is agreed, and the whole system of
Clean Waters Dam No. 1 and leachate dam diversion/spillway will
be required to have a 1:100 years overflow capacity.
Water Quality - the basement earth under proposed
stockpiles (particularly the high grade stockpiles), waste
and tailings dumps and dams should be made impervious by
rolling and compaction with suitable soils and clays.
- the disposal of sewage and possible impacts should be
addressed.
Corrinent:
Groundwater is not a significant resource in the area of Drake.
The ability of the subsoil and rock strata to attenuate
contaminants in leachate has been determined and is high. This
will retard the migration of contaminant through basement
materials during the construction phase. Surface sealing and
rehabilitation will further reduce the rate of movement by
reducing the flow of water through the dump. The rate of
leaching will be further examined during the detailed design
phase. The EIS states that the risk of groundwater contamination
from leachates is minimal and this remains the proponent's view.
If additional leachate studies show that compaction is necessary
then it will be done. At this stage there is no requirement
since the rate of contaminant generation is slow and the soils
have a high capacity to attentuate the contaminants.
All accommodation is in Drake township. There would be no more
than 30 people at the minesite at any one time. Matters relating
31
GS 1984/340
to sewage disposal will be discussed in detail with the
Tenterfield Shire Engineer and resolved according to Shire
requirements.
The Shire is already aware of these implications of the project.
Storage Overtopping - consideration should be given to a
dam across Sawpit Creek downstream of the tributaries
draining the site. All surface drainage from the site,
together with leachates entering surface flows, would be
successfully intercepted by the dam. Given a volume of
about 60 ML, this dam would have a retention time of one
month during average rainfall conditions. In conjunction
with the planned pollution control structures, this dam
should allow time for heavy metal ions to combine with
suspended organic ligands and settle into the sediments.
Corrment: The function of the recommended additional dam is already met by
the proposed water retention structures, except for a greater
than 1 in 20 year rainfall event.
Mine rehabilitation - problem of an open pit at the end of
operations be further considered, as infilling by rain and
groundwater could be a long term problem.
Corrrnent: The current Lady Hampden open pit contains acid water high in
dissolved metals. After the redevelopment of the resource and
the completion of mining, a substantial amount of the acid-
generating material will have been removed from the pit as ore or
waste and will be handled by the waste management strategy.
Therefore, the effect on groundwater quality of the final pit
will be similar, but probably less, than the present pit. No
users of groundwater will be affected. The water level in the
pit will be that of the water table and as at present, the pit
will not overflow. Groundwater samples from down drainage of the
present pit will be assayed to determine the effects of present
pitwater infiltration.
32
GS 1984/340
Acid Ore Neutralisation - Reliance on the acid neutralising
properties of the rock accompanying the ore should be
justified and/or reconsidered.
Corrment:
The EIS does not rely solely on acid-neutralising materials in
waste rock to contain acids formed by sulphur oxidation. It is
true that in old mine dumps, its acid-neutralisers have been
consumed and net acid-generation is occurring. This is because
the waste material classification, emplacement and drainage
measures as proposed in the EIS were not carried out.
Chemical Storage
Corrtnent:
These matters would be the subject of regular inspection and
monitoring by Mines Inspection Division of DIR.
Soil Management
Coninerit:
Soil erosion controls are outlined in the EIS and will be
developed in more detail as required, in conjunction with the
Soil Conservation Service.
(1) Safeguards
Comnent:
Safeguards for water management, waste management and
rehabilitation are specified at an appropriate level of detail in
the EIS and further investigations, in the form of monitoring
during operation, are foreshadowed. The areas requiring
monitoring are described. This work will be progressively
detailed and will be continuously modified as results come to
hand during the operating phase.
Consultation with tiTe Commission has occurred through the
Commission's Grafton regional office (February 1984 presentation
by the JV at Drake). Continued consultation is envisaged if
required during operation of the mine.
33 GS 1984/340
5.0 ASSESSMENT OF ENVIRONMENTAL IMPACP
At a production rate of 250,000 tonnes per annum, the Drake
project is quite small and the potential impact on the
environment is proportionately minor(provided adequate safeguards
are applied). The major issues concern water quality, water and
waste management and land rehabilitation.
5.1 Vegetation and Terrestrial Fauna
a) Vegetation
The effects of mining and treatment operations will be localised.
The open cuts, mill site, waste dumps and tailings area would
necessitate the clearing of around 35 ha of vegetation, with
additional clearance for roads and other works. Some of these
areas are already extensively disturbed. The vegetation types
likely to be disturbed are of fairly widespread occurrence in the
region and any small decrease in their area would be of minor
significance. The evidence of the vegetation survey is that rare
and endangered species would not be affected.
Because of the relatively high rainfall and the low
susceptibility of most of the soils to erosion, the regeneration
of mined areas should present no problems provided suitable
procedures are followed.
b) Fauna
The construction of the Lady I-Iampden mine and associated
facilities will cause partial or total loss of fauna habitat in
that area. The perpetuation of this effect at Lady Hampden, with
localised extensions, represents a very small proportion of land
already cleared for the Drake township, pasture at "Bunijah" and
"Cheviot Hills" and forestry. In regional terms such disturbance
around Drake amounts to little. In this context, the direct
habitat effect of the project is negligible.
34 GS 1984/340
Noise and dust from construction and operation, although not
anticipated to be great, will displace animals from an area
larger than that covered by the mining site itself. Small
marsupials and birds are vulnerable to predation by cats.
Domestic and feral cats, and probably dogs, are likely to
increase with the human population unless controls are
implemented on their introduction. Domestic refuse should be
properly disposed of to minimize food supplies for feral animals.
The killing of animals by vehicular traffic is a problem wherever
roads are built, and some losses are inevitable but generally
insignificant. Increased human population size increases
problems associated with shooting, cross-country driving and
bushfires but with appropriate controls and education, these need
have little effect on the fauna.
5.2 Aquatic Biota and Water Quality
Aquatic Biota
It is possible that a net improvement in water quality will occur
with renewed mining at Lady Hampden. This should benefit the
aquatic ecosystems in the Upper Plumbago drainage, which at
present are depleted in the streams immediately downstream of old
mining activity, including the Lady Hampden mine.
Water Quality
Leaching waste dumps and adits associated with old mine workings
at Lady Hampden, Mt. Carrington, Silver King, White Rock and
others have been polluting the Upper Plumbago Creek for some 80
years.
The redevelopment of Lady Hampden under the present proposal will
place this pollution source within the controls of the projects
water and waste management scheme.
An effect of the redevelopment of Lady Hampden, therefore, is to
possibly improve the water quality of the upper Plumbago
catchment by permanently eliminating one of its existing
pollution sources.
35
GS 1984/340
Against this potential long term beneficial consequence of the
project are effects during the commissioning of the developments.
- Sedimentation to Sawpit Creek during early construction
activities, while the sedimentation control dams are being
installed.
- Potential for early acid leaching from waste dumps as they
are being built.
In fact, the geochemical testwork to date shows significant
carbonate-buffering in the waste rock which suggests that there
will be sufficient time to complete and seal the waste
emplacements before net acid-generation sets in.
In the context of the past 80 years of pollution around Drake,
these short term effects are considered quite insignificant.
- Improvements to the water quality of Plumbago Creek are difficult
to quantify. At present chemical and biological indicators show
- that the creek has returned substantially but not entirely to
normal water quality and a diverse complement Gf invertebrates at
a distance of no more than 20 km downstream of Lady Hampden.
5.3 Specific Impacts From Mining Proposals
The mining operation will have several areas of environmental
impact as follows. Steps for alleviation of each impact are
briefly outlined.
a) Visual appearance of overburden and waste dumps: Waste
dumps will be stabilised and designed for re-vegetation.
Topsoil will be removed before dumps are established and
stockpiled for use in re-establishing the natural
vegetation.
- b) Run-off water from ore stockpiles and waste dumps: All
run-off will be collected and re-used as process water
supply for the mill. The containment system will be
36
GS 1984/340
designed with sufficient capacity so that any discharge
during flood conditions will be diluted to allowable
levels.
5.4 Specific Impacts from Milling Proposals
Areas of impact resulting from the milling process are as
follows, with steps for their alleviation:
Tailings : The conical hill formed by the discharge of
thickened tailings will result in a stable land form and
allow reclamation of all process and run-off water, which
will be re-used in the mill circuit. Tailings will be
placed at a pH of approximately 11.5, with high lime
content. Presence of cyanide will be monitored to maintain
a level near zero, and any cyanide present would be
destroyed on the tailings area.
Cyanide is an expensive commodity and any loss is
commercially unacceptable. It also rapidly breaks down on
exposure and is not a long term contaminant.
Topsoil will be removed from the tailings area to assist in
revegetation of the tailings hill.
Dust from crushing operations : The proposed treatment
process eliminates secondary and tertiary crushing and
screening, leaving only a jaw crusher. The dust generation
potential is therefore significantly reduced. Fine water
sprays will be used at the primary crusher to control dust
emission.
5.5 Noise from Mining and Milling Operations
Noise impact from mining and milling is expected to be minimal.
A noise study was undertaken to determine present background
noise levels and to predict the level of noise which will be
generated by the mine and mill operations.
37 GS 1984/340
a) Site details
The site is surrounded on all sides by moderate to heavily
timbered hills. The nearest residences are located at Drake, two
kilometres to the south on the Bruxner Highway. The noise study
described below was directed at the noise impact of the proposed
operation on these residences, all other residences being too
remote from the site and further shielded by trees, undergrowth
and hills.
b) Summary of mine operation
It is proposed to win the raw material by blasting and then
convey the material by front-end loader to the jaw crusher.
After crushing the material will be fed into a ball mill thence
leaching tanks, smelting and to store. The blast holes will be
drilled by a track drill.
The crusher will operate between the hours of 0700 and 1700
hours, Monday to Friday whereas all other equipment may be
operated twenty four hours a day, seven days per week.
C) Noise level prediction
The level of noise which will be generated by the proposed
equipment on this site is as follows:-
Track Drill 99dB(A)
Jaw Crusher 85dB(A)
Ball Mill 101dB (A)
F/E Loader 83dB (A)
Dump Trucks 80dB (A)
All the above levels are at a distance of 7m.
38 GS 1984/340
Distance attenuation
To establish the attenuation which will be achieved over distance
in the environment of the proposed operation the following
procedure was carried out.
A broad spectrum noise source was located on the site of the
proposed operation. The noise level of the noise source was
measured at a distance of 4m.
By making further noise measurements at distances of 128, 256 and
512 metres from the noise source a distance attenuation figure of
lldB(A) per doubling of distance was established over a greater
distance than 128 metres.
This result means that over a distance of between 7 and 2000
metres a loss of 67dB(A) will be experienced through distance
attenuation.
By applying this attenuation to the generated noise levels of the
equipment proposed it is evident that the acceptable level of
background noise level + 5dB(A) will not be exceeded at the
nearest residence.
f) Traffic noise
Haulage of ore will be confined to the mine site and will not
pass near Drake township. Deliveries of supplies will pass
through Drake, as will employees travelling to and from work.
The increase in this truck traffic will be minor when compared
with existing cattle and logging traffic on the Bruxner Highway
through Drake township.
Approximately 70 staff will be employed at the mine and will
travel to the site by motor vehicle along Cheviot Hills Road. As
the mill is working a 24 hour shift approximately 20 employees
will travel at one time and then probably with more than one
person per vehicle.
39 GS 1984/340
There will only be one shipment from the mine per week. The only
additional traffic will be maintenance and service vehicles on a
random basis.
Daily mine traffic will consist, on average, of 3 five-tonne
trucks delivering supplies and equipment, 3 light commercial
vehicles, and 20 trips of cars, utilities and vans. This gives
an average total of 26 additional vehicles per day on the Bruxner
Highway.
The most recent figure for daily traffic passing through Drake is
460 vehicles for 1980. The projected figure for the end of 1984
is 497 vehicles daily (2% compound growth rate). Figures are
from the Department of Main Roads, Glen Innes office.
g) Assessment of noise impact
The noise study has concluded that no adverse noise impact will
- result from the operation of the proposed development, nor should
any justifiable complaint relating to noise result from such
- operation, based upon the current specifications for the plant
and machinery to be used, and providing all equipment is
maintained in accordance with good engineering practice and to
the manufacturer's specification.
5.6 Social Iwpacts and Benefits
Construction will be by sub-contractors, who will recruit some
employees locally. The total construction workforce will vary
from 10 to 40. Mining will also be by about 15 contract
personnel and the project company state that there will be
approximately 55 company personnel employed.
The company expects most personnel to live in Tenterfield and
Casino but will provide accommodation during the week at Drake
- for about 35 people (expanding from the present 15).
The social impacts of the project, as well as noise, transport
and other impacts are expected to be low in Drake. Employment
40
GS 1984/340
and flow-on benefits of income and employment generation are
expected to benefit Tenterfield and Casino townships. The
project will also create Commonwealth, State and Local Government
revenue as well as generate export income and profits for the
company.
41
GS 1984/340
6.0 ENVIRONMENTAL SAFEGUARDS AND MANAGEMENT
6.1 Proposed Water Management Scheme
- a) Principles
The proposed water management system has been based on a number
of management principles designed to control water discharge from
the site whilst at the same time providing the necessary quantity
of water required for ore treatment.
The principles adopted are summarised below:
To provide adequate water storage to satisfy consumption
requirements of the ore treatment plant.
To maintain process water within a closed water system.
This system will be designed to provide retention for a
design rainfall condition given by 1 in 20 year 24 hour
rainfall (increased •from 1 in 10 year in the EIS)
To provide sediment dams around stockpile and other
disturbed areas to prevent off-site discharge of sediments
created by mining operations. These sediment dams will be
designed to retain run-off up to a design rainfall
condition given by the 1 in 5 year 24 hour rainfall.
To avoid, where possible, significant changes to the
natural water system by the design and operation of stream
diversions. (Run-off from undisturbed areas will be
diverted away from the site and prevented from becoming
contaminated)
To provide adequate water for dust control requirements
within the mine pit, on haul roads, and on waste and ore
stockpiles.
(f) To provide adequate potable water storage to meet potable
water requirements.
42 GS 1984/340
The water system will essentially be divided into two. The
primary system will be a closed circuit designed to provide water
for the ore treatment plant and will include control of run-off
and leachate from ore and high to medium grade waste ore
stockpiles.
The secondary system will control sediment and run-off from waste
and low grade waste ore stockpile areas and other disturbed areas
on the site.
Initial mine water for start-up will be taken from the existing
pit and if necessary from Sawpit Creek. There do not appear to
be other users of Sawpit Creek water who might be affected.
b) System Description
The proposed water management system is shown on Figure 6. The
major components include:
Mine pit
Stockpiles - ore grade
- high and medium grade waste ore (HMGW)
- low grade waste ore (LGW)
- waste rock (WR)
Clean water dams and diversion channels
Sediment dams
Tailings storage
Mill and works areas
These components are described in detail below, as follows:-
Mine Pit:
In its final state, the mine pit will cover about 4.5 hectares
and will have a final void volume of the order of 1000 Ml. This
pit is currently about 0.3 hectares in area. Dewatering bores
will minimize groundwater inflow to the pit.
Water from the existing pit and surface inflows will be pumped to
the stockpile leachate dam for storage prior to use within the
43
GS 1984/340
closed water system. (For future analysis, the annual yield has
been assumed to be 150 Ml per annum)
When mining has been completed, water from the tailings storage
will be transferred to the mine pit void, prior to the
rehabilitation of the tailings storage area.
Stockpiles:
Mined material will be divided into different grades for on-site
storage purposes. These grades will be ore grade, high grade
waste, and low to barren wastes. This will maximise conservation
of the resource by allowing possible future recovery.
Studies of leachate have indicated that the quality of run-off
from the two lowest grade stockpiles (i.e. waste and low grade
waste) will not be significantly different from typical clean
overburden. These two stockpiles will be located to the north of
Sawpit Creek, immediately south of a ridge line, in order to
reduce interruption to undisturbed area drainage, and will be set
back as far as possible from Sawpit Creek itself. Run-off from
these stockpiles will be channelled to two sediment dams
designated as Sediment Dams Nos. 1 and 2.
The higher grade stockpiles which are more likely to be processed
will be located closer to the mill, and have been identified as
being more likely to produce poorer quality run-off (particularly
acidity). Run-off from these areas has thus been included within
the closed water system, and will drain to the stockpile leachate
dam along with other run-off from the mill and crusher areas.
Stockpile Leachate Dam:
This dam will be located on a small tributary of Sawpit Creek.
The maximum top water level has been notionally set to a level of
RL 479m, which will produce a storage of about 10 Ml over an area
of about 1 hectare.
This dam will act as a run-off interception storage for the ore
- grade, high grade waste and medium waste stockpiles, and for
operational areas in the vicinity of the mill and crusher. It
44
GS 1984/340
will also act as a store for water pumped from the mine pit
during dewatering operations.
In order to prevent over-utilisation of this storage, this water
will be used as the first source of make-up water for the mill.
In emergencies, this storage will be outfalled directly into the
mine pit.
The stockpile leachate dam will be isolated from the surrounding
catchment by a clean water dam (No.1) to the south, and a
diversion channel. The diversion channel will allow creek flows
to by-pass the natural flow path and the channel will also act as
an interceptor for undisturbed run-off from the east, thus
preventing natural run-off from flowing into the closed water
system.
Clean Water Dams and Diversion Channels:
Clean water dams will be constructed as soon as approval to
proceed is given. It is expected that water collected in these
dams during the construction of the other facilities will provide
water for start-up.
Clean Water Dam No. 1 will provide the first opportunity to
collect make-up water from outside the mine water system. Since
this dam may not be able to provide all make-up water
requirements, particularly during a dry period, an additional
clean water dam, Dam No.2 will be provided:
It is expected that Dam No. 2 will provide for the bulk of make-
up water and any potable water needed. However, if the quality
of this dam water does not meet requirements for potable water,
this water may need to be obtained from a well.
Sawpit Creek has been observed to flow most of the time, which
indicated that apart from direct run-off from rainfall events,
groundwater inflows may contribute a baseflow component.
Diversion works will be required at two locations as follows:
45
GS 1984/340
(a) On Sawpit Creek at the northern edge of the mine pit. This
diversion will be about 150 metres in length and will
divert Sawpit Creek around the perimeter of the mine pit.
- (b) From Clean Water Dam No. 1 to Sawpit Creek. This diversion
will be about 550 metres in length and will take excess
storage from the clean water dam to Sawpit Creek.
Sediment Dams:
Sediment Dam Nos. 1 and 2 will be provided to protect Sawpit
Creek from contamination by sediment contained in run-off from
the waste and low grade waste stockpiles.
Tailings Storage:
The tailings storage area will be about 18 hectares in area and
will receive process water containing tailings. The bund walls
surrounding the tailings area will be properly engineered
structures. A design criterion of 1 in 20 years will be used in
sizing this storage (increased from 1 in 10 years in EIS)
In such a situation the dilution factor in Sawpit Creek, Plumbago
Creek and the Clarence River is likely to be such that if excess
water from the tailings area flowed into the drainage system at
that time, the effects would be insignificant. The flood sampling program undertaken in May 1983 gives some insight into
this likelihood, where the relative concentrations of pollutants
decline due to dilution factors as the floodwaters rise, although
the total loads may in fact increase.
On the assumption that the rainfall would be uniform over the
three stream catchments and the tailings area catchment, then the
proportion of the tailings overflow to simultaneous natural
discharges will be as follows, where the tailings area catchment
is approximately 0.2 sq. km: Sawpit Creek 7% (based on an
approximate catchment area of 2.8 square kilometres at Water
Sampling site D2), Plumbago Creek 0.1% (catchment area 177 sq.km
at site W19) and Clarence River at Tabulam, 0.01% (catchment area
3783 sq.km, site W21).
46 GS 1984/340
Mill and Work Areas:
Run-off from the mill and surrounding work areas will be
contained and channeled into the stockpile leachate dam where it
will be treated in the same manner as run-off from the higher
grade waste stockpiles.
c) Run-Off and Control
Good quality run-off high in suspended solids will be treated by
sediment dams designed to retain the 1 in 5 year 24 hour flood.
Run-off of generally poorer quality will be directed into the
closed water system where it will be used as process make-up
water.
Sediment Dams 1 and 2:
In sizing these sediment dams, it has been assumed that a storm
run-off co-efficient of 0.7 will apply over the whole area of the
waste stockpiles. However, in practice only a portion of the
stockpile area will be bare at any time as progressive
landforming and rehabilitation will take place, and thus this
value is considered conservative.
The following table shows the required parameters for Sediment
Dams Nos. 1 and 2. m rr r' .
Sediment Dam Design Parameters
Sediment Catchment Design Storm Run-Off Design Storm Dam Area Rainfall Co-efficient Run-Off Volume
(ha) (mm/hour) (Ml daily)
1 4 3.9 0.7 2.6
2 3 3.9 0.7 2.0
47
GS 1984/340
These sediment dam sizes represent the volume contained by a 50m
x 50m storage area with an average depth of 1 metre. (As
mentioned earlier, these are conservative estimates of the
required size)
Stockpile Leachate Dam:
This dam will act as both a sediment dam and transfer dam for
water within the closed water system. As stated in the previous
section, if top water level is set at RL 479, a total volume will
be about 10 Ml over an area of about 1 hectare. The following
table shows that this will comfortably meet sediment dam
requirements using the 1 in 10 year 24 hour rainfall event.
Furthermore a 1 in 20 year retention final design basis has been
required by the Department of Mineral Resources.
TABLE 6.2
Stockpile Leachate Dam Design Parameters
Catchment Area (ha)
6.2 Design Rainfall (mm/hour) 5.7 Storm Run-off Co-efficient 0.7 Design Storm Run-Off Volume (Ml daily) 5.9
Given that this dam will be called on to provide make-up water
for the mill, out flow is unlikely during mine life. In any
case, if out flow should occur, this will be directed into the
mine pit. Sufficient extra capacity is also available for
disposal of water obtained from mine dewatering spear points.
Groundwater Management:
It is proposed to pre-empt the formation of acid pit water by a
series of dewatering bores. The principal source of present and
future potential groundwater inflow to the pit has been
identified as Sawpit Creek, and bores will be placed to intercept
these flows accordingly. The quality of this groundwater appears
suitable for process water.
48 GS 1984/340
d) Water Balance
The water balance for the proposed water management system
demonstrates that sufficient water will be available to meet
annual and longer term water demands.
Mill water requirements are as follows:
M3/hr Mi/annum
Mill feed water 79 600 Return to process water tank after
thickening stage 49 370 Disposal to tailings storage 31 235
These mill water transfers are based on mill operation for 350
days per annum for approximately 22 hours per day. They are also
assumed to be independent of rainfall conditions provided there
is sufficient make-up in dry years.
Rainfall, evaporation and run-off data adopted for the water
balance analysis are given below:
Mean annual rainfall 990mm Annual rainfall exceeded 1 in 10 years 1490mm Annual rainfall exceeded 9 in 10 years 694mm Mean annual evaporation 1800mm Evaporation pan factor 0.85 Annual stockpile run-off coefficient 0.2
This data can be used to calculate water balances under wet
(1490mm rainfall), average (990mm) and dry (694mm) rainfall
conditions.
The following table shows the major annual water transfers
subject to varying rainfall conditions.
GS 1984/340
TABLE 6.3
Major Annual Water System Transfers
Component Rainfall Catchment Annual Run-Off Annual Condition Area (ha) Co-efficient Yield (Ml)
Tailings Average 18 1 -150 Storage Wet 18 1 -100 (Net Loss) Dry 18 1 - 10
Sediment Average 1 1 - 5 Leachate Dam Wet 1 1 - 10 (Net Loss) Dry 1 1 - 1
Run-Off to Average 6 0.2 10
Sediment Wet 6 0.2 15
Leachate Dam Dry 6 0.2 5
Run-Off to Average 63 0.2 120
Clean Water Wet 63 0.2 190
Dam 1 Dry 63 0.2 90
Run-Off to Average 152 0.2 300
Clean Water Wet 152 0.2 450
Dam 2 Dry 152 0.2 210
Make-Up water:
- In an average year, no additional make-up water will be required.
However, within the year, it is most likely that some make-up
water will be required in drier months.
- In a dry year, about 60 Ml of extra water will be required.
It is unlikely that Clean Water Dam No. 1 could meet this
demand alone. Water will have to be drawn from Clean Water
Dam No. 2.
50
GS 1984/340
- A further safety factor is built into dry years. In these
years, it is highly unlikely that tailings storage or
stockpile leachate dam evaporation losses would apply over
the full 18 ha and 1 ha areas respectively, since drawing
down during dry periods will reduce the evaporative area.
Wet Year System Storage:
-
The balance shows that in wet years, excess water must be
held within the system. This excess storage is calculated
as resulting in a 209 Ml increase in the tailings storage.
This volume can be stored in the 18 ha tailings area at an
average depth of about 1.2 metres. Taking into account
storage loss due to solids disposal, this infers that the
bund constructed to retain the tailings runoff should be
approximately 2.5 metres high to prevent out flow more than
once in 10 years. However a final design basis of 1 in 20
years is to be used for tailings storage. Therefore a bund
wall higher than 2.5 m at the lowest point will be designed
in accord with this criteria. Under conditions • in excess
of the 1 in 20 year return period, overland flow and stream
discharges are expected to dilute the concentrations in
decant water entering Sawpit creek to below the statutory
limits. In addition, decant water is returned by pumping
to the mill circuit and this can be diverted to the pit.
- The mine pit remains the ultimate emergency disposal point
for excess storage adjoining the pit and the mill.
e) Water treatment
During mining and processing, leachate and run-off water from
waste dumps and tailings and water from the pit will be contained
on site. The methods of waste emplacement deployed during the
operation of the mine, and the rehabilitation of completed
emplacements will have ensured that hazardous leachates are not
generated after decommissioning.
The feasibility of achieving this objective is demonstrated by
the solid waste management program outlined in Section 6.2, which
51
GS 1984/340
controls the generation of contaminated leachates by selective
placement of wastes, compaction and rehabilitation.
The basis for the program is a series of geochemical tests to
establish the acid-generating potential of waste materials.
Preliminary results from these tests, along with site water
quality monitoring of existing leachates, pit water and existing
groundwater data suggest the following:
- Drainage from the waste rock dumps (WR) is unlikely to be
acid or contaminated with heavy metals.
- Leachates from the waste ore dumps (medium to high grade
waste, MHGW and barren to low grade waste, LGW) and ore
stockpile will initially be non acid. However, in the long
term a low concentration of acid may be produced from the
LGW dump and a moderate concentration of acid produced from
the MHGW dump and ore stockpile. (ote that the complexity
of acid mine drainage formation and sub-surface hydrology
means that some polluted water can be produced during
construction of dumps and may require treatment.
Geochemical investigations of wastes indicate that acid
formation is initially restricted due to the presence of
carbonates and other acid neutralising minerals in the
rocks).
The quality of drainage from existing suiphide rock dumps and in
the pit has been measured by the Department of Mineral Resources
and the proponent. The results suggest that if no attempt is
made to control the generation of acid then contaminated drainage
will occur with an upper limit composition as follows:
pH: 2.6 - 3.0
Total acidity (to pH 7): 500 - 700 mg/i CaCO3.
Electrical conductivity: 2-3 mS/cm
Fe: 50 - 150 mg/l
Potentially hazardous levels of Cu, As, Pb and Cd.
52 GS 1984/340
This water has relatively low total acidity and is amenable to
low cost treatment using lime and/or limestone neutralisation
techniques. Since the geochemical testing shows that there is a
delay before acid is produced site monitoring will be used to
assess the need for installation of a water treatment facility.
If it is shown that water treatment is necessary to control
contamination by acid generation, then a number of alternative
water treatment options are available. These will depend on
final water quality resulting from the water and waste management
plans. The treatment and disposal options available are:
- Waste rock - acid water co-disposal. The geochemical
testing shows that the waste rock and waste ore has a high
acid neutralising capacity. Waste water could be pumped to
absorption trenches or sprayed onto waste dumps in
locations with adequate neutralising capacity. This method
of disposal will require monitoring.
- Discharge at periods of high flow. The viability of this
will depend on the dilution and buffering potential of the
receiving water.
- Directly used for plant make up water or dust suppression.
- Treatment by mixing with alkaline waters on site before
reuse or discharge. The tailings water is likely to be
highly alkaline since the plant will be maintained at a pH
of approximately 11.5.
The existing groundwater contains some alkalinity and water from
dewatering bores may be mixed with acid water and achieve
adequate neutralisation.
Due to the kinetic control on acid formation, water collecting in
the pit will be rapidly pumped out. This will minimise the
contact time with acid forming materials and reduce the level of
contamination. The subsequent use, treatment or disposal option
for this water will depend on its quality and volume.
53
GS 1984/340
6.2 Proposed Solid Waste Management and Rehabilitation Schemes
Only a small fraction of the rock to be excavated at Lady Hampden
is metal and therefore, essentially the total amount must be
accommodated in the solid waste management system. Wastes
include weathered rock, fresh rock and solids from the tailings
disposal system. The waste rock will be segregated into different
grades based on the metal content; waste Rock and low grade
wastes (WR) contain up to about 70 g/t silver and high grade
waste (HGW) contains more than about 70 g/t. There will be
approximately 2.63 mt of WR, and 0.18 mt of HGW. 1.5 mt of ore
of more than 80 g/t Ag will be processed and dumped as tailings.
If economically viable the HGW, and possibly some of the low
grade wastes, will be processed to extract metal at a later date.
The waste management and rehabilitation program outlined in this
section incorporates this temporary stockpiling constraint.
Contingency plans are presented for full rehabilitation of all
wastes if the market considerations do not support processing
prior to decommissioning of the plant.
The findings of the waste rock geochemistry and soil
investigations, along with the findings of the baseline
environmental survey and mining method, form the basis for the
waste management and rehabilitation program outlined by the
proponent.
a) Principles
Waste management and rehabilitation at Lady Hampden will aim to
firstly rectify the past mismanagement of waste from the old open
cut. Secondly, the new operation will be planned to contain all
disturbance to the Sawpit Creek catchment and to selectively
place wastes to minimise the generation of contaminated drainage
and to avoid surface soil contamination. Rehabilitation works
will aim to stabilise wastes, control erosion and promote
revegetat ion.
54 GS 1984/340
Testing, classifying and quantifying the various waste types will
continue as a routine planning input to the mine and waste
handling operation. The results of these tests will be used to
continually update the management strategy outlined in this
report.
b) Waste Handling
Waste Rock and Waste Ore Stockpile - Geochemical Testwork
Waste rock geochemical testing examined four waste types, as
shown in Table 6.4. Composite samples were collected from 21
boreholes and are considered to be representative of the wastes.
Table 6.4 shows the important acid forming features of the waste
types and the dumps where the wastes will be placed. The
location of the dumps is shown on Figure 2.
TABLE 6.4
Waste Rock Acid Potential
Dumps Waste Type Ag S ANC NAPP HMGW LGW WR
g/t %CaCO3 %CaCO3
Medium & High 50-80 5.3 1.4 15 X Grade Waste Ore
Sulphide Waste *50 33 1.3 9 X X
Non Suiphide Waste *80 0.41 2.9 -1.6 X X X
Oxidised Waste *80 0.32 0.7 0.3 X X X
ANC: Acid neutralising capacity
NAPP: Net Acid Producing Potential = Potential acid calculated
from total sulphur minus ANC.
X: Indicates dumps in which waste types will be placed.
"less than"
55 GS 1984/340
Table 6.4 shows that the medium to high grade waste (MHGW) and
the sulphide waste (SW) have a net acid producing potential
equivalent of 15 and 9% CaCO3 equivalents respectively. These
are classified as hazardous acid forming wastes. The oxidized
waste (OW) has a low acid potential and the non sulphide waste
(NSW) is non acid-forming. Batch leaching and batch equilibrium
tests commenced in January 1984 on each of the waste types.
The results show that under the test conditions applied none of
the waste types produced an acid extract. However, in the OW,
MHGW and the SW there is evidence of sulphide oxidation and acid
neutralisation as shown by elevated levels of Ca, Mg and SO4.
Preliminary solubility analyses of the results show that gypsum
is probably controlling the solubility of Ca and SO4 in OW and
SW. The results also indicate that the initial leachate from the
wastes will have a low concentration of heavy metals.
Calculations based on the estimated sulphide oxidation rate
enables the rate of consumption of the acid rieutralising capacity
and the time when acid leachates are produced to be predicted.
The findings of these calculations are as follows:
- Non sulphide waste is non acid-forming.
- Oxidised waste may produce a very low concentration of acid
after 2 years. This is a very conservative estimate since
not all the sulphur in the waste is likely to be reactive
sulphide.
If acid is formed it may require a light lime application for
revegetation, however no leachate problems are anticipated.
- Sulphide waste will become acid after approximately 6
years.
- Medium and high grade waste will become acid after
approximately 1 year.
GS 1984/340
Waste Handling:
The volume of the various waste types, the order of excavation
from the pit and placement in dumps provides the basis for waste
handling. The results of -waste rock characterization show that
with selective handling, acid forming wastes can be buried within
the core of the LGW and WR dumps. The acid material can be
covered with oxidized and non sulphide waste and compacted. This
will minimise generation of acid leachate and prevent surface
soil contamination. The results show that there is a substantial
time lag before acid is produced. This will enable greater
flexibility with selective handling. In practice, wastes will be
dumped from benches. This procedure will enable selective burial
to be achieved. It may be necessary to use smaller lifts so that
additional compaction can be achieved. This approach is
currently being tested at another metalliferous mine in NSW to
reduce leachate generation from the waste rock dump. If
applicable, the recommendations from this trial will be
incorporated into the waste disposal operation at Lady Hampden.
Tailings:
Geochemical assessment of the tailings has not been carried out,
since tailings materials were not available. The tailings will
most likely have an acid producing potential. However, due to
the inherent and added neutralising capacity it is not expected
that a significant pH drop will occur during the life of the
emplacement. Subsequent clay sealing and soil covering will
further reduce the rate of sulphide oxidation and minimise the
generation of contaminated leachate. Results from waste rock
geochemistry work show that the basement soils have a very high
capacity to attenuate contaminants in leachates and therefore
retard any subsurface movement.
Detailed investigations of the tailings geochemical behaviour
will be carried out when sufficient material is available.
C) Landform Construction
All waste rock dumps will be constructed using trucks dumping
from benches. The wastes will be classified ahead of mining by
on site laboratory testing in conjunction with ore grade testing.
57 GS 1984/340
The dumping requirements for each mine block can then be
determined. In this fashion the outer surface of dumps will be
- constructed of oxidized and non suiphide waste.
Since the material in the MHGW dump and the LGW dump is likely to
be processed the dumps will be constructed to shed water as
rapidly as possible. The slopes will not be reshaped unless
market factors indicate that processing is unlikely before
decommissioning of the plant or it is necessary for leachate/run-
off control. Reshaping of the waste rock dump (WR) will be
carried out. The final slope will be approximately 18° with two
5 metre benches. The dumps will reach a maximum RL of 510m which
raises the existing land surface by up to 30 metres.
The tailings will form a conical hill approximately 15m high and
500 metres in diameter, which will be a stable landform and
suitable for revegetation once covered with soil.
On the WR dump the benches will be used to convey overland flow
to properly constructed rip-rap drop structures. The design of
all drainage works will be undertaken prior to commencement of
mining.
Run-off from the MHGW and LGW dumps will be directed over the
benches unless rehabilitation is required. If this is the case,
a concept similar to that for the waste rock dump will be
applied.
At the completion of open cut mining there are a number of
options for the use of the pit including the following:
Disposal of tailings from processing of the lower grade
waste ores or ore from other deposits in the region.
Allowed to fill with water. Since the high sulphide
material will have been excavated and other suiphide rocks
will be deep in the resulting lake, it is possible that the
final water quality will be acceptable. Sawpit Creek and
surface run-off would be redirected to prevent entry into
58 GS 1984/340
the pit. Further examination of this option will be
carried out during mining if considered a viable
alternative.
(c) Since the pit limits have been defined on economic rather
than geological cut offs it may be desirable to leave the
pit open for future access to ore reserves. Steep slopes
would be battered back, a perimeter fence erected and
suitable drainage provided. The most likely options are a)
or c) or a combination of these two. If the pit is filled
with tailings it will be returned to natural contours with
a suitable soil cover and revegetated.
d) Rehabilitation
The objectives of rehabilitation are to stabilise the land,
minimise erosion and return the land to a forested system where
practicable. Following reshaping of the WR dump, also other dumps
if required, 150 to 300mm of topsoil will be placed and sown to
pasture and/or a cover crop to stabilise the slopes. Trees will
be planted according to recommendations from the Forestry
Commission. If necessary the dumps will be ripped prior to
topsoiling and precautions taken to avoid compaction of soil.
Criteria for soil management are outlined below.
Following processing of the temporary stockpiles (LGW and MHGW)
the basement sub-soil will be evaluated for potential
phytotoxicity and treated or removed prior to replacement of
topsoil. If these stockpiles are not processed they will be
rehabilitated in the same manner as the waste rock above.
Surface treatment of the tailings dump will depend on the
chemical and physical characteristics. A cover consisting of one
or all of the following will be placed prior to revegetation:
Compacted outer surface; clay seal;
non-acid waste rock; topsoil.
59
GS 1984/340
A small existing tailings dam is located on the northern edge of
the final pit. This area will be similarly rehabilitated in its
current form, or after tailings removal and re-processing.
Detailed planning and implementation of the erosion and drainage
controls and revegetation program (including fencing requirement
and fire and weed control) will be developed in consultation with
the Soil Conservation Service, the Forestry Commission and the
Department of Mineral Resources. These discussions will take
place prior to and during the mining and processing operations.
e) Soil Management
Waste Handling:
Prior to dumping of any waste the area will be cleared of timber
and the topsoil picked up and stockpiled. Economic timber will
be selectively logged and the remainder burnt. This will be a
progressive operation to keep the area disturbed at any one time
to a minimum and to minimise the stockpiling time for soil.
Soil types were identified during the soil survey and the depth
suitable for topsoil stripping varies from zero to 300mm.
Chemical and physical testing of the soils is being conducted to
establish guidelines for soil management. Stripping, stockpiling
and respreading operations should be closely supervised to ensure
that these costly operations are not jeopardised by incorrect
soil handling.
Soil Handling:
Care needs to be taken during tree clearing operations to
minimize the disturbance to the immediate surface as this is the
most valuable component of the soil profile. Clearing should be
undertaken when the soil is neither moist nor dry but somewhere
in between (usually about 5-10% moisture content). Soil
stripping should be carried out at a similar moisture content.
Prior to stripping the area should be surveyed to determine the
exact stripping depth in each segment.
60 GS 1984/340
Ideally stripped soils should be placed directly onto areas that
have undergone reshaping and surface preparation. At Drake some
temporary stockpiling of topdressing material will be necessary.
This soil should be stockpiled on as flat an area as possible.
Because of limited space at Drake, it will be necessary to
construct deep, 2-3 metre stockpiles. To avoid excessive
compaction, these should be built using trucks rather than
scrapers. The surface should be left very rough thereby
increasing depression storage and promoting infiltration. The
boundaries of stockpiles need to be clearly marked out and
operators advised not to drive any equipment over them.
Soil should be respread at moisture contents between 5 and 10%
and care taken to prevent compaction. Rubber tyred vehicles
should be avoided for this phase of the soil handling procedure.
Soil should be spread along the contour. Following soil
application the surface should be deep ripped at a horizontal
interval of 3m along the contour and discontinuously so that
individual depressions approximately lOm long are formed. This
will help to encourage infiltration and promote revegetation.
f) Conditions at Mine Shutdown
The site will be rehabilitated according to the statutory
requirements and policy guidelines of the Department of Mineral
Resources, the Soil Conservation Service and the Forestry
Commission and returned as far as possible to a forested system.
Measures for rehabilitation of the waste dumps, tailings area and
mine pit have been described above. All other plant, except for
reinforced concrete foundations, will be removed.
6.3 Environmental Safeguards
a) Water Management
Controls:
Safeguards and controls will be provided to minimise
contamination of the environment. These will include:
61
GS 1984/340
Sediment retention dams to remove suspended matter from
water prior to being released from site.
Diversion channels to separate 'types of run-off and to
- direct selected types off-site.
An emergency storage will be provided by using the mine pit
in the case of overtopping of the stockpile leachate dam
which holds the process water.
Diversion channels will be constructed to the same Cross-
section as the original channel and scour protection
provided if necessary.
A monitoring programme will be established for early
detection and control of contamination during mining and/or
processing operations. A staff officer (for example the
mine manager) will be nominated to act as environmental
coordinator and liaison officer.
Site Monitoring and Contingency Plan:
Monitoring of surface and groundwater will be carried out by the
company to assess the effectiveness of the adopted water and
solid waste management strategy and to determine the need for an
alternative approach. Leachates from dumps with the greatest
potential to produce acid (ore stockpile and MHWR dump) and the
mine pit water will be contained in the stockpile leachate dam.
If there is a failure in the system or a condition during high
flow when discharge is not permitted this water can be directed
into the pit. Subsequently the water can be treated before
discharge or re-use.
Initially, site monitoring will include the determination of
flow, and measurement of the following parameters:
GS 1984/340
pH Conductivity Total acidity
++ +++ Fe(total),occasionally Fe /Fe Zn, Cu,Pb,As,Mn, Cd so4
Total suspended solids (TSS)
This list will be rationalised following collection of adequate
data and establishment of good correlations between the various
parameters.
Monitoring of Catchment Water Quality:
Existing water quality in the Sawpit Creek and Plumbago Creek
catchments was established for a range of conditions during the
1981 and 1983 water quality studies. Monitoring of four selected
sites will be carried out by the company during the project
development, initially with monthly samples assayed for the
following:
pH Conductivity Cu,Pb,Zn,As, Cd,Mn,Fe so4 TSS
The monitoring sites are W3, Dl, D2 and W19. All except W3 were
monitored regularly throughout 1983. The site can be monitored
on a random check basis by the Department of Mineral Resources.
b) Waste Management and Rehabilitation
All wastes will be placed in the Sawpit Creek catchment. This
will enable a simple water monitoring network to quickly locate
any potential hazards. Environmental safeguards are inherent in
the environmental setting and will be incorporated into an
ongoing monitoring and management program.
63 GS 1984/340
The major hazard from rock weathering is the production of acid
mine drainage and acid waste. A monitoring program will be
implemented along with the ore-grade testing to determine the
acid potential and dumping requirement of each block prior to
excavation. The testing will include the determination of total
sulphur and the acid-neutralising capacity.
The subsoils and weathered rock beneath the dumps have a capacity
to attenuate contaminated leachates. An assessment of the likely
migration distance of hazardous concentrations of heavy metals in
soil from waste rock and tailings leachate is continuing.
Results suggest that in 30 years the contaminant front is likely
to have penetrated less than 200m into the old land surface. The
risk of groundwater contamination from leachates is therefore
minimal especially since rehabilitation of waste dumps will
reduce the flow of water through the dumps.
Rehabilitation will be carried out progressively on the WR dump.
Ongoing monitoring and management will be carried out to assess
revegetation success and to contain and repair eroding areas.
Detailed physico-chemical investigations and revegetation trials
will be carried out on the tailings and other waste rock dumps
(MHGW and LGW) to develop the best strategy for rehabilitation
well ahead of the need.
64 GS 1984/340
7.0 CONCLUSIONS AND RECOMMENDATIONS
7.1 Conclusions
In considering the proposed activity the Department of Mineral
Resources has examined and taken into account to the fullest
extent possible all matters likely to affect the environment, and
in so doing has considered all representations received in
relation to the environmental impact statement. Copies of all
submissions have been referred to the Secretary, Department of
Environment and Planning pursuant to Section 113(3) of the EPA
Act.
The Department of Mineral Resources, based on the foregoing
environmental assessment, is satisfied that the opencut mining
operation proposed by Mount Carrington Mines Limited can be
undertaken in a manner which will not detrimentally affect the
environment, subject to the provision of adequate environmental
safeguards and the incorporation of appropriate conditions of
authority in the leases.
The ongoing satisfactory application of all necessary
environmental safeguards and practices will be subject to annual
review through an environmental management plan and report
concept, to be incorporated in lease conditions. One of the
major advantages of this system will be that it will provide
annual formalised opportunity for coordinated input from (in
particular) the Forestry Commission, Soil Conservation Service,
the State Pollution Control Commission and the Department of
Mineral Resources.
The Department agrees in principle to the proposal being carried
out in the manner described in the Company's environmental impact
statement but incorporating modifications outlined in this
Assessment Report. Specifically the major modifications required
are as follows.
- Tailings dam to be designed to retain 1 in 20 years flood
condition.
65
GS 1984/340
- Tailings dam to have a spiliway capable of passing the 1 in
100 years flood condition.
- Leachate dam to be designed to retain 1 in 20 years flood
condition.
- Clean waters dam No. 1 / leachate dam / diversion channel
system to have a capability of passing the 1 in 100 years
flood condition.
- Sediment dam 1 in 5 years.
In respect of noise, air and water quality, the State Pollution
Control Commission will undertake consideration of these aspects
in determining approvals required under the Noise Control Act,
the Clean Air Act and the Clean Waters Act.
7.2 Recommendations to the Minister for Mineral Resources and
Energy
The Department of Mineral Resources recommends to the Minister
for Mineral Resources and Energy that a) approval be given to
Mount Carrington Mines Limited, being the registered holder of
Mineral Lease 5883 (Act 1906), and Special Lease 409 (Act 1906),
to mine within, and subject to, the conditions of the said leases
and the additional conditions to be attached thereto; b)
approval be given to an additional mining purpose, being "to
remove overburden to give access to any mineral", for Mining
Purposes Lease 24 (Act 1973) registered in the name of Mount
Carrington Mines Limited; and c) leases, in satisfaction of
Mining Lease Applications 598, 628, 629 (Inverell) and 247-254
(inclusive), 264, 273, 274 and 277 (Teriterfield), be granted to
Mount Carrington Mines Limited pursuant to Section 53(2) of the
Mining Act, 1973, subject to the conditions to be attached
thereto.
In respect of Mining Purposes Lease Application 643 (Inverell),
registered in the name of Mount Carrington Mines Limited, it is
recommended that consideration be given to the grant of a lease
at a later date once administrative procedures necessary for this
application have been completed.
GS 1984/340
Appendix 1
Newspaper advertisement relating to
public exhibition of EIS.
67
GS 1984/340
Newspaper advertisement relating
to public exhibition of EIS
NEW SOUTH WALES DEPARTMENT OF MINERAL RESOURCES
Assessment of Environmental Impact of a Proposed Silver and Gold Mine
near Drake PUBLIC EXHIBITION
The NSW Department of Mineral Resources is undertaking an environmental impact assessment of a proposal by joint venturers Aberfoyle Ltd and Mount Carrington Mines Ltd to carry out a silver and gold mining operation at the Lady Hampden mine near Drake, some 70 km west of Casino.
The joint venturers propose to extract by open cut methods some 250,000 tonries of ore per year for at least 6 years. Bullion will be produced on site by a crushing, flotation and leaching process.
An environmental impact statement has been prepared for this proposal and will be on public exhibition for the period 28th June 1984 to 27th July 1984 at the following locations during their respective normal opening hours.
Department of Mineral Resources, 23rd Floor, 8-18 Bent Street, Sydney and 214 Beardy Street, Armidale. Tenterfield Shire Council, Council Chambers, Tenterfield. Abe rloyle Ltd., Project Office, Bruxner Highway, Drake.
Department of Environment and Planning, 175 Liverpool Street, Sydney. NSW Government Information Ce ntre, 55 Hunter Street, Sydney. NSW Environment Centre, 399 Pitt Street, Sydney.
Copies of the statement are available for sale at a cost of $25.00 from:
Department of Mineral Resources, 23rd Floor, 8-18 Bent Street, Sydney 2000.
Persons or organisations wishing to comment on the environmental impact of the proposed mining operation are invited to make written submissions before 30th July 1984 to the:
Secretary, Department of Mineral Resources,
8-18 Bent Street, Sydney 2000.
MM
GS 1984/340
Appendix 2
Requirements of the Director,
Department of Environment and Planning
we GS 1984/340
Letter from Department of Environment and Planning dated 30/5/84
Our reference: 80/1994 The Secretary, Department of Mineral Resources, C.A.G.A. Centre, 8 Bent Street, SYDNEY. N.S.W. 2000
Proposed Alluvial Gold/Silver Mining Operation by Aberfoyle Exploration Pty. Ltd. and Others at M.L. Nos. 346, 5883, 598, M.P.L.24 etc. Drake.
For your information Natural Systems Research Pty. Ltd. has consulted the Director concerning the preparation of an environmental impact statement for Aberfoyle Exploration Pty. Ltd. and others at Drake.
Attached is a copy of the advice forwarded to Natural Systems Research Pty. Ltd.
In terms of section 112 of the Environmental Planning and Assessment Act, 1979 in respect of the activity, the determining authority is required to obtain, examine and consider an environmental impact statement (E.I.S.) that is prepared in the prescribed form and manner.
When an adequate E.I.S. has been prepared for the subject proposal, as determining authority, you should proceed with the matter in accordance with sections 112 and 113 of the Act and place the document on public exhibition. The procedures for public display that are to be followed by the proponent and/or determining authority are as in clauses 60 to 64 of the Environmental Planning and Assessment Regulation, 1980.
At such time as copies of the completed E.I.S. and development application are forwarded to the Secretary., it would be appreciated if two additional copies of the E.I.S. could be forwarded; also details of the period of public exhibition and proposed public display locations. Should any submissions be made during the period of public exhibition, such submissions should be forwarded to the Secretary and in the event of issues of interest to the Department being raised, we will advise you accordingly.
Your advice to the applicant outlines the Director's requirements regarding the form and content of the E.I.S. These matters should be taken into account in determining the proposal and we have suggested that the applicant concur with you in this regard.
Yours faithfully
C.J. Wright Manager, Assessments Branch. As Delegate for the Director
70
GS 1984/340
NEW SOUTH WALES DEPARTMENT OF ENVIRONMENT AND PLANNING
ATTACHMENT
PROPOSED ALLUVIAL GOLD/SILVER MINING OPERATION BY ABERFOYLE EXPLORATION PTY. LTD. AND MOUNT CARRINGTON MINES LTD. ON M.L. 346, M.L. 5883, M.P.L. 24, M.L. 598 etc., at DRAKE.
A comprehensive environmental impact statement should adequately cover all the matters specified in Clause 34 of the Environmental Planning and Assessment Regulation, 1980.
These matters should be clearly and succinctly outlined in the text and where appropriate supported by adequate maps, plans, diagrams or other descriptive details to enable all concerned to gain a clear understanding of the full scope of the development and its likely impact on the environment.
The following particular matters should be included in its coverage:
1. Background information.
Broad nature and extent of works proposed. Land tenure, boundaries, site details in relation to environmental planning instrument zorlings and any other land use constraints. Description of existing land use, land slopes, soils, vegetation and drainage patterns of the area subject of the development application.
2. Detailed description of the proposal.
This description should not only describe the proposal at the site but also describe any associated operations such as winning and transport of materials, processes involved (highlighting proposed crushing, if any) , disposal of wastes, rehabilitation, landscaping and use of the end product if likely to have environmental implications.
Particular matters to be covered include:-
Characteristics and economic significance of the resource. Details of proposed Mining method. Plans of operations, production rates, method of treating and disposal of tailings. Type of machinery and equipment to be used. Expected life of the operation. Storage of chemicals; volume; locality of and safety measures to be adopted. Water supply source and alternative sources; other users of if any. Quantities of water to be used. Significance of flora and fauna that may be affected by the proposal. - Tailings dam siting and method of operation; recycling of waste waters; impact upon water table; expected period of use and odours, if any.
71 GS 1984/340
Number of persons to be employed. Hours of operation. Times of any crushing envisaged. Location and quantity of any necessary stockpiling. Access arrangements - truck routes and number of truck movements. Quantity of materials to be processed. Proposals for erosion control; progressive stages in the work, rehabilitation of site, tailings dam etc. and assurances of effective completion.
Description of the environment.
This description should provide details of the environment in the vicinity of the development site and also of aspects of the environment likely to be affected by any facets of the proposal suitably quantified where appropriate. In this regard, re1ated physical and economic aspects of the environment should be described to the extent necessary for assessment of the environmental impact of the proposed development.
Assessment of environmental impact and measures to be taken to reduce the impact especially with regard to:-
The effect of extraction on the sediment transport rate of any river; the possibility of siltation or other downstream effects.
The effectiveness of proposed measures for erosion control.
Any likely cumulative effects of the proposed operations.
Water treatment and pollution control measures.
Disposal of waste material including control of leachate and treatment thereof.
Likely noise disturbance caused by the operations, including transport operations, on nearby residences if any.
Impact on native flora and fauna.
Landscaping measures and effects on the visual environment.
The proposed final use of the site and likely effectiveness of rehabilitation.
Any likely affectation of sites of aboriginal, archaeological or heritage value if located in the vicinity of the operations.
72
GS 1984/340
5. Authorities contacted.
The names of authorities contacted should be listed including the State Pollution Control Commission, Department of Mineral Resources, National Parks and Wildlife Service. Any comments relating to specific matters of interest raised by such authorities should be declared, including those in relation to possible cumulative environmental problems that may result.
73
GS 1984/340
Letter from Department of Environment and Planninq dated 12/11/84
The Under Secretary, Our reference: 80/1994(z)Z Department of Mineral Resources, C.A.G.A. Centre, G.P.O. Box 5288, Your reference: M80/6118 SYDNEY, N.S.W. 2001 00
Attention: Mr. J.M. Hawke
Dear Sir,
Re: EIS for Proposed Mine near Drake
Thank you for your letter dated 23rd August, 1984 which pursuant to section 113(3) of the Environmental Planning and Assessment Act, forwarded copies of submissions received during the period of public exhibition of the environmental impact statement in respect of the above matter.
With regard to the exhibition of the EIS, we note that, whilst no submissions were received from the public, a number of submissions have been received from various Government authorities and that some of these have raised a number of points of considerable concern.
The Department has examined the submissions received and considers that the proposal is one of local significance. The Department therefore considers that your Department may proceed to make appropriate determination in respect of the proposed activity, subject to the views of relevant authorities, as set out below, being taken into account in this process.
The proposed mine will be situated in the Girard State Forest. It is therefore important that the concerns raised by the Forestry Commission in respect of its management responsibilities for this area be taken into consideration in your assessment of the subject proposal and that the Forestry Commission be fully consulted in this regard. In particular, we draw your attention to the following:
rehabilitation and revegetation procedures to meet the requirements of the Forestry Commission. The Forestry Commission has expressed considerable concern in respect of the area to be affected by the proposed tailings Hill. Serious consideration should be given to disposal of tailings in the open cut after the completion of mining as proposed by the Forestry Commission to prevent a major future management problem in the State Forest.
the establishment of adequate procedures for the storage of cyanide on site.
74
GS 1984/340
the management of waste waters during wet weather with particular emphasis on emergency storage for stockpile leachate disposal.
Details of monitoring programmes and responsibilities for carrying out and evaluating monitoring should be discussed with the Forestry Commission.
The Water Resources Commission has also made a number of recommendations relating to design criteria for dams, and diversion channels which should be considered for inclusion in any approval to be granted to the proposed mine. The WRC has also stressed its concern in respect of leachates from stockpiles, cyanide waste spills and these aspects of the proposal should be carefully controlled. In this respect it is considered that the advice of the Water Resources Commission and the State Pollution Control Commission be incorporated in any approval to be given to the mine.
Finally, the proposal will involve the relocation of a public road and consent should be sought from Tenterfield Shire Council and the Forestry Commission in this regard.
The Department would appreciate being informed of significant amendments to the proposal which arise out of the above considerations. Further, it would be appreciated if the Department could receive a copy of the report prepared by you pursuant to clause 64 of the Environmental Planning and Assessment Regulation, 1980, when it is available.
Yours faithfully,
C.J. WRIGHT Manager, Assessments Branch
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