Compelling Gum Creek Scoping Study
Released
Released
Announcement PDF
18 March 2024
COMPELLING GUM CREEK SCOPING STUDY
Key Points
The Scoping Study (“Study”) indicates that near surface open pittable gold resources at the
100% owned Gum Creek Gold Project (“Project”) will deliver compelling financial outcomes.
Projected average recovered gold production of approximately 84,000 ounces per year
processed through a new 2.4 million tonne per annum gravity / CIL plant over a 10-year Life of
Mine (LOM).
Initial open pit mine production target of 24.46Mt @ 1.13g/t Au for 888,000 ounces (76%
Indicated, 24% Inferred) from selected deposits. “There is a low level of geological confidence
associated with Inferred Mineral Resources and there is no certainty that further exploration
work will result in the determination of Indicated Mineral Resources or that the production target
itself will be realised.”
Robust financial metrics returned using a conservative A$2,900/oz base case pricing
assumption and current industry costings:
Pre-tax cashflow of A$574M, pre-tax Net Present Value at an 8% discount rate
(NPV8) of approximately A$318M, and pre-tax IRR of 31.5%.
Payback period from commencement of mining of 3.0 years.
Study base case gold price is approximately A$400/oz below the current spot gold price,
representing significant potential upside to predicted financial outcomes. The A$3,300/oz gold
price scenario returns:
Pre-tax cashflow of A$904M, pre-tax NPV8 of approximately A$548M, and pretax IRR of 45.8%.
Payback period from commencement of mining of 2.1 years.
Pre-production capital cost of A$238.5M includes a new 2.4Mt per annum gravity / CIL
processing plant, a new 200-person camp, and a 20% capital cost contingency.
LOM C1 cash operating cost of A$1,730/oz produced, and LOM all-in sustaining cost of
A$1,931/oz produced.
Additional resource drilling to focus on expanding the shallow oxide resources excluded from
the Study and potentially further enhance the positive economic outlook of the highly
prospective Gum Creek Project.
Underground mining options at all deposits including Swan/Swift, Kingfisher, Omega, and
Wilsons are yet to be evaluated.
1
Horizon Gold Limited ACN: 614 175 923
Suite 8, Level 3, 47 Havelock Street, West Perth WA 6005 | PO Box 39, West Perth WA 6872
Telephone: +61 8 6331 6092 | Email: info@horizongold.com.au | Website: www.horizongold.com.au
________________________________________________________________________________
Important Note - Cautionary Statement
The Scoping Study referred to in this announcement has been undertaken to determine the viability of
open pit mining at Horizon Gold’s Gum Creek Project in Western Australia, with processing of selected
deposits to be undertaken at a new processing plant constructed at the previous Gidgee Gold
Processing Plant location. The Study is a preliminary technical and economic assessment of the
potential viability of the Project. It is based on low level technical and economic assessments that are
not sufficient to support estimation of Ore Reserves. Further evaluation work and studies are required
before the Company will be able to provide assurance of an economic development case.
Of the mineral resources scheduled for extraction in the Study mine production target, approximately
76% of the resource ounces are classified as Indicated, with the remaining 24% classified as Inferred.
There is a low level of geological confidence associated with Inferred Mineral Resources and there is
no certainty that further exploration work will result in the determination of Indicated Mineral Resources
or that the production target itself will be realised.
The Company has concluded that it has a reasonable basis for providing these forward-looking
statements and the forecast financial information included in this release based on the material
assumptions outlined in this release. These include assumptions about the availability of funding. While
the Company considers all the material assumptions to be based on reasonable grounds, there is no
certainty that they will prove to be correct or that the range of outcomes indicated by the Study will be
achieved.
To achieve the range of outcomes indicated in the Study, pre-production funding in the order of
A$238.5 million will likely be required. Investors should note that there is no certainty that the Company
will be able to raise that amount of funding when needed. It is possible that such funding may only be
available on terms that may be dilutive to or otherwise affect the value of the Company’s existing
shares.
It is also possible that the Company could pursue other ‘value realisation’ strategies such as a sale,
partial sale or joint venture of the Project. If it does, this could materially reduce the Company’s
proportionate ownership of the Project. Given the uncertainties involved, investors should not make
any investment decisions based solely on the results of the Study.
Horizon Gold has concluded it has a reasonable basis for providing the forward-looking statements
included in this announcement and believes it has a ‘reasonable basis’ to expect it will be able to
complete the development of the mineral resources outlined in the attached Scoping Study Report
(Appendix 2). This announcement has been prepared in compliance with the JORC Code 2012 Edition
(JORC 2012) and the ASX Listing Rules. All material assumptions on which the forecast financial
information is based have been provided in this announcement and are also outlined in the attached
JORC 2012 table disclosures. Given the uncertainties involved and listed above, investors should not
make any investment decision based solely on the results of the Study.
________________________________________________________________________________
2
Introduction
Horizon Gold Limited (ASX: HRN) (Horizon or the Company) is pleased to announce the results of a
scoping study that assesses the economic potential to recommence production from near surface, free
milling open pittable gold resources at the 100%-owned Gum Creek Gold Project (Gum Creek or the
Project) located in the Murchison Region of Western Australia (Figure 1). Gum Creek has historically
produced more than 1 million ounces of gold and currently hosts a gold resource of 2.14 million
ounces 1. The Project covers 519 square kilometres of granted tenure over the highly prospective and
underexplored Gum Creek greenstone belt, which contains 37 open pit and three underground gold
mines.
The Company has considered various options to recommence gold mining at Gum Creek including
mining and toll treating ore at the closest operating gold processing facilities, however it has determined
that constructing and operating a new gravity / CIL processing plant is the optimum business strategy
for the Project.
The Study envisages an initial mine production target of 24.46Mt @ 1.13g/t Au for 888,000 ounces
(76% Indicated, 24% Inferred 2) from selected deposits, with an average recovered gold production of
approximately 84,000 ounces per year over a 10-year mine life, processed through a new 2.4 million
tonne per annum gravity / CIL processing plant located at the previously permitted Gidgee mill site.
Established infrastructure including air strip, haul roads, tailings dam, waste dumps, in-pit water
resources, camp (for construction and overflow purposes) and existing ROM pads have been used in
the Study and upgraded where required.
Figure 1: Gum Creek Gold Project and surrounding gold resources and gold
processing operations.
1
Refer to Horizon Gold Limited ASX announcement titled “19% Increase in Gold Resources at Gum Creek Project” dated 15 May 2023.
There is a low level of geological confidence associated with Inferred Mineral Resources and there is no certainty that further exploration
work will result in the determination of Indicated Mineral Resources or that the production target itself will be realised.
2
3
Scoping Study Summary
The Study evaluates free milling Whittle in-pit gold resources optimised using a base case gold
price of A$2900/oz (+/- A$200/oz and +/-A$400/oz).
All gold resources in the Study are located on granted mining leases within the 100% owned Gum
Creek Gold Project.
Only deposits with greater than 15,000 gold ounces inside Whittle pit shells from previous pit
optimisation work were included in the Study, which equates to only 14 of the current 26 Gum
Creek Gold Project resource areas.
Ore to be processed through a new 2.4Mt per annum gravity / CIL processing plant located at the
previously permitted Gidgee gold processing site.
Existing Native Vegetation Clearing Permit could be used for clearing the proposed processing
infrastructure area (processing plant), and the Swan, Swift, Eagle and Shiraz deposit areas.
Mining Proposal (ID 46008) is currently approved for the Swift deposit and the Gidgee processing
infrastructure area.
Initial open pit mine production target of 24.46Mt @ 1.13g/t Au for 888,000 ounces comprised of
76% indicated and 24% inferred gold resource ounces (compliant with the JORC 2012 guidelines).
Average recovered gold production of approximately 84,000oz per year over a 10-year LOM.
LOM C1 cash operating costs of A$1,730/oz produced including:
LOM Mining: A$34.30/t milled (A$993.6/oz produced)
LOM Processing: A$23.61/t milled (A$684.1/oz produced)
LOM General and Administration (G&A): A$1.82/t milled (A$52.7/oz produced)
LOM All-in Sustaining Costs (AISC) of A$1,931/oz produced including:
LOM Sustaining Capital: A$3.88/t milled (A$112.4/oz produced)
LOM Royalties (Govt & 3rd party): A$3.05/t milled (A$88.4/oz produced)
Pre-production capital cost of A$238.5M including existing plant demolition and removal, a new
2.4Mt per annum gravity / CIL processing plant, a new 200-person camp, pit dewatering costs, and
a 20% contingency.
LOM sustaining capital cost of A$94.9M including an additional Tailings Storage Facility (TSF),
ongoing pit dewatering capital and Property Plant & Equipment (PP&E) costs.
Compelling financial outcomes at A$2,900/oz gold price:
Pre-tax cashflow of A$574M, pre-tax NPV8 of approximately A$318M, and pre-tax IRR
of 31.5%.
Payback period from commencement of mining of 3.0 years.
Study base case gold price is approximately A$400/oz below the current spot gold price,
representing significant potential upside to predicted financial outcomes.
The A$3,300/oz gold price scenario returns:
Pre-tax cashflow of A$904M, pre-tax NPV8 of approximately A$548M, and pre-tax IRR
of 45.8%.
Payback period from commencement of mining of 2.1 years.
4
Upside to Study outcomes:
Excellent potential to extend the proposed mine life through underground mining and other
processing methods.
Underground mining options at all deposits including Swan/Swift, Kingfisher, Omega and
Wilsons are yet to be evaluated.
Additional shallow resource expansion drilling at the 12 resource areas not included in the
study could potentially increase the resource size and gold grade of these deposits and
elevate them to an economically viable status for inclusion into the mining schedule.
Managing Director Leigh Ryan said:
“The Study highlights the Gum Creek Project’s potential robust financial metrics for a stand-alone gold
processing facility in a world class Western Australian gold jurisdiction and shows a pathway for
delivering value to shareholders.
The Study includes only the free milling open pittable portions of 14 of our 26 mineral resource areas
and the Company is confident that through further resource drilling additional shallow oxide gold
resources will be defined at the remaining 12 resources and other areas, to potentially become part of
the current mine plan, extending the LOM well beyond the 10-year mine life envisaged in this Study.
Almost 50% of the Study mine production target ounces are sourced from the Swan / Swift deposit
which is scheduled to be mined in years 1 to 5, and over 80% of these in pit resource ounces qualify
as indicated resources (compliant with JORC 2012 guidelines). This will allow for a simple, low risk
mining operation to progress during the estimated 3 year capital expenditure payback period and allow
ample time for mining preparations at satellite deposits to take place, and time for additional resource
drilling to be completed.
Existing granted clearing and mining proposals should enable a quick transition to mining at Gum Creek
and once established, the processing facility will become a strategic asset for the region with the
potential to consolidate some of the surrounding stranded gold assets.
We’re very pleased with the results of the Study and are preparing to commence a feasibility study and
other activities that further enhance the Project’s positive economics on our path to becoming the
region’s next gold producer.”
5
Gum Creek Gold Resource Estimate
On 15 May 2023 the Company announced an updated Mineral Resource Estimate (MRE) for the Gum
Creek Gold Project of 44.45Mt @ 1.50g/t Au for 2.14 million ounces contained gold (Table 1)
reported in accordance with the JORC Code (2012 Edition) and based on documentation prepared by
Competent Persons as defined by the JORC Code guidelines. A summary of the current MRE is
detailed in Table 1 below. The MRE contains 26 discrete deposit areas that are a mixture of open cut
and underground resources.
No Ore Reserves have been declared for the Gum Creek Gold Project.
Table 1: Gum Creek Gold Resources as at 15 May 2023
Cut-off
grade
(g/t Au)
Resource
Date
Swan/Swift OC
Swan UG
Swift UG
Wilsons UG
Howards
Kingfisher OC
Kingfisher UG
Heron
Heron South
Shiraz
Eagle
Wyooda
Snook
Hawk
Toedter
Specimen Well
Wedge
Camel Bore
Kearrys
Psi
HypernoReliance
Melbourne
Bitter
Deep South
Reliance
Eagles Peak
Orion
Wahoo
Fangio
Jul-22
Jul-22
Jul-22
Jul-13
May-23
May-23
May-23
May-23
May-23
May-23
May-23
Jul-22
Jul-22
May-23
Aug-16
May-23
May-23
Jul-22
May-23
Jul-22
0.4
2.5 / 3.0*
3.0
1.0
0.4
0.6
1.5
0.6
0.8
0.4
0.8
0.8
0.8
0.6
0.5
0.8
0.6
0.8
0.6
0.8
May-23
Indicated
Au
Tonnes
Gold (oz)
(g/t)
9,980,000
301,000
2,131,000
8,064,000
621,000
359,000
330,000
720,000
2,539,000
395,000
430,000
75,000
378,000
379,000
450,000
100,000
1.09
6.91
5.33
0.82
1.77
3.48
2.11
1.79
0.70
1.94
1.56
2.57
1.28
1.47
1.24
2.08
349,500
66,900
365,000
213,100
35,400
40,200
22,400
41,400
57,300
24,700
21,600
6,200
15,500
17,900
18,000
6,700
0.6
119,000
1.73
May-23
0.6
214,000
May-23
0.6
May-23
Jul-22
Jul-22
May-23
0.6
0.8
0.8
0.6
Inferred
Au
Tonnes
Gold (oz)
(g/t)
Tonnes
Total
Au
(g/t)
Gold (oz)
1.06
6.99
5.72
5.36
0.81
1.58
3.31
1.60
1.66
0.68
1.85
1.56
1.82
1.26
1.54
1.50
1.52
1.42
1.25
1.81
434,100
118,500
25,400
391,000
266,900
45,100
135,700
110,600
78,900
78,900
68,800
64,800
54,000
34,400
34,000
25,500
23,800
21,800
20,000
19,000
445,000
1.31
18,800
6,100
362,000
1.44
16,800
1.56
2,400
224,000
1.62
11,700
0.99
1.40
1.25
1.35
1,300
8,200
10,400
1,300
305,000
251,000
258,000
129,000
1.16
1.43
1.25
1.33
11,400
11,500
10,400
5,500
2,735,000
226,000
138,000
136,000
2,136,000
269,000
917,000
1,822,000
761,000
1,064,000
764,000
862,000
846,000
471,000
689,000
529,000
487,000
100,000
46,000
226,000
0.96
7.10
5.72
5.95
0.78
1.12
3.24
1.51
1.53
0.63
1.80
1.56
1.76
1.25
1.54
1.50
1.52
1.21
1.35
1.69
84,600
51,600
25,400
26,000
53,800
9,700
95,500
88,200
37,500
21,600
44,100
43,200
47,800
18,900
34,000
25,500
23,800
3,900
2,000
12,300
12,715,000
527,000
138,000
2,267,000
10,200,000
890,000
1,276,000
2,152,000
1,481,000
3,603,000
1,159,000
1,292,000
921,000
849,000
689,000
529,000
487,000
479,000
496,000
326,000
6,600
326,000
1.16
12,200
1.56
10,700
148,000
1.28
176,000
1.64
9,300
48,000
264,000
69,000
99,000
1.19
1.49
1.32
10,100
3,300
4,200
41,000
182,000
258,000
30,000
Total
28,193,000 1.48 1,346,000 16,257,000 1.51 791,300
44,450,000 1.50 2,137,300
* Cut-off grades are 2.5g/t Au for Swan Underground (UG) Indicated, and 3.0g/t Au for Swan UG Inferred.
** Wyooda includes the Kingston Town, Think Big and Manikato resources which are within 600m and 200m of each other respectively.
Notes: Figures have been rounded. The information in this announcement that relates to the reporting of the Wilsons, and Toedter Mineral
Resources has been extracted from the Horizon Gold Limited ASX announcement titled “Gum Creek Gold Project Resource Update”
dated 12 February 2021 and is available to view at https://horizongold.com.au/announcements/. The information in this announcement
that relates to the reporting of all other Mineral Resources has been extracted from Horizon Gold Limited ASX announcements titled “32%
Increase in Resources at Gum Creek Gold Project” dated 25 July 2022 and “19% Increase in Gold Resources at Gum Creek Gold Project”
dated 15 May 2023, both of which are available to view at https://horizongold.com.au/announcements/.
6
Open Pit Mine Production Target
The Study in-pit mine production target totalling approximately 24.46Mt @ 1.13g/t Au for 888,000
ounces is sourced from 14 deposits including Eagle, Hawk, Heron South, Howards, Hyperno-Reliance,
Kingfisher, Manikato, Shiraz, Snook, Specimen Well, Swan/Swift, Think Big, Toedter, and Wedge
(Table 2). Of the mineral resource ounces scheduled for extraction in the Study production target,
approximately 76% are classified as Indicated and 24% as Inferred 3 during the 10-year proposed LOM.
The open pit mine production target is reported within optimised Whittle pit shells generated by Auralia
Mining Consulting using a base case input gold price of A$2900/oz. The pit shells are based on typical
contractor mining parameters and up-to-date average operating costs for deposits of a similar scale
and geological nature. The production target includes a mining recovery of 95% and a mining dilution
of 10%.
Cut-off grades were calculated in Whittle and varied by deposit and weathering based on processing
recoveries and haulage distance with values of between 0.3g/t Au and 0.6g/t Au calculated. The
production schedule reported low grade material between the calculated lower economic cut-off grade
and 0.6g/t Au, with high grade material being greater than 0.6g/t Au.
Table 2: Scoping Study Open Pit Mine Production Target by Deposit
Deposit
Swan/Swift OC*
Howards*
Eagle
Heron South
Toedter
Hawk
Kingfisher OC
Hyperno-Reliance
Manikato
Shiraz*
Snook
Specimen Well
Think Big
Wedge
Total
Tonnes
10,396,000
8,160,000
1,145,000
907,000
566,000
765,000
256,000
328,000
335,000
491,000
158,000
252,000
431,000
274,000
24,463,000
Production Target
Au (g/t)
1.29
0.85
1.08
1.17
1.48
1.09
2.11
1.25
1.20
0.81
1.83
1.52
1.06
1.65
1.13
Ounces
431,000
222,000
40,000
34,000
27,000
27,000
17,000
13,000
13,000
13,000
9,000
12,000
15,000
15,000
888,000
* MIK models constructed as diluted mining models, hence no further dilution mining dilution or mining recovery factors have been
applied.
Notes: Figures have been rounded.
The Whittle optimisation work in this Study used the mineral resource estimates referred to in previous Horizon Gold Limited ASX
announcements titled “Gum Creek Gold Project Resource Update” dated 12 February 2021, “32% Increase in Resources at Gum Creek
Gold Project” dated 25 July 2022 and “19% Increase in Gold Resources at Gum Creek Gold Project” dated 15 May 2023, all of which
are available to view at https://horizongold.com.au/announcements/.
3
There is a low level of geological confidence associated with Inferred Mineral Resources and there is no certainty that further exploration
work will result in the determination of Indicated Mineral Resources or that the production target itself will be realised.
7
Open Pit Mining and Mining Schedule
Auralia Mining Consulting were engaged to complete pit optimisation work using Whittle software to
create a series of pit shells providing an optimal discounted cash flow (DCF). To simplify the study,
only deposits containing more than 15,000 gold ounces inside Whittle pit shells from previous pit
optimisation work were included in the Study.
Pit shells were produced using typical contractor mining parameters and up-to-date average operating
costs for similar sized deposits of a similar geological nature. Mining costs used in the pit optimisation
process included dewatering, grade control, drill and blast, load and haul (using rigid class haulage
fleets and medium (100t-150t class) excavators, and ore haulage including haul road upgrades and
maintenance. Ancillary and overhead costs used in pit optimisation work included dozing, ground
control, engineer/geologist/surveyor salaries, contractors and all site General & Administration (G & A)
costs.
Conventional drill and blast practices have been assumed using suitable drilling rigs and sampling
procedures on 5m benches, incorporating Ammonium Nitrate-Fuel Oil (ANFO) in dry and Emulsion
bulk product in wet conditions.
Density inputs are determined by previously reported specific gravity work and vary according to
oxidation surfaces as used in previously announced mineral resource estimates. Metallurgical
recoveries, pit wall angles, State and third-party royalties, and refining costs were all factored into the
optimisation process.
In-pit mineral resources for this Study are reported within optimised Whittle pit shells generated using
a base case A$2900/oz gold price. Sensitivity analysis pit optimisation runs used A$2500/oz,
A$2700/oz, A$3100/oz and A$3300/oz. The in-pit production targets include a mining recovery of 95%
and a mining dilution of 10%.
Scheduling for the open pit mining was completed using Excel spreadsheets incorporating optimised
in-pit volume and resource data reported against optimised pit shells. No pit designs have been
completed for this study. The open pits are planned to be excavated with conventional surface mining
methods. Benches are to be 5m high and will be mined in 2.5m flitches. Pit wall angles were designed
based on geotechnical recommendations specific to each pit, varying from a minimum of 30 degrees
in fill material to 56 degrees in competent fresh rock. The resulting average waste to ore strip ratio for
the optimised pits in the Study is 5.2:1.
Top-down mining assumptions were used with a mining rate of up to 16,000 Bulk Cubic Metres (BCM)
per day per excavator. The schedule assumes initial utilisation of two 100t to 150t excavators and two
777 haul truck fleets for the Swan/Swift area and to complete mining of the smaller satellite pits before
reducing to one fleet when mining the smaller satellite pits and the Howards pit. Road trains will be
used for longer distance hauling from the northern and southern deposits beginning in year 6.
The Company’s strategy is to mine larger, lower risk open pit deposits adjacent to the proposed
processing area (Swan/Swift) that return substantial profit margins in the first 5 years of mining
incorporating the other “Central” satellite pits during the 3rd year of mining (Eagle, Wedge, Hawk and
Kingfisher). Due to higher strip ratios, from year 6 the “Northern” satellite pits (Shiraz, Snook, Specimen
Well and Toedter) and “Southern” satellite pits (Hyperno Reliance, Heron South, Manikato and Think
Big) will be mined while the 2 haul truck fleets are on site. Howards will be mined from year 7 to 10
using a single fleet (Figure 2). The average LOM recovered gold production using a calculated average
gold processing recovery of 95.1% is estimated to be approximately 84,000 ounces per year.
Scheduled ore mined (tonnes per annum) and the ore grade (g/t) is presented in Figure 3.
8
Quarterly Production (tonnes) by Mining Location
5,000,000
4,500,000
4,000,000
3,500,000
3,000,000
2,500,000
2,000,000
1,500,000
1,000,000
500,000
-
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44
SwanSwift1
SwanSwift2
SwanSwift3
SwanSwift4
Howards1
Howards2
Howards3
Eagle
Wedge
Hawk
Kingfisher
Shiraz
Snook
Specimen Well
Toedter
Manikato
Think Big
Hyperno Reliance Heron South
Figure 2: Quarterly Production Schedule by Deposit
Mined Ore
1.80
3,500,000
1.60
3,000,000
1.40
2,500,000
1.20
2,000,000
1.00
1,500,000
0.80
0.60
1,000,000
0.40
500,000
0
0.20
0
1
2
LG Ore - Tonnes Mined
3
4
5
6
HG Ore - Tonnes Mined
7
8
Low Grade g/t
9
10
11
0.00
High Grade g/t
Figure 3: Annual Ore Mined (tpa) and Ore Grade (g/t)
Metallurgy, Processing and Power Supply
The Study assumes the existing Gidgee processing facility will be removed and replaced with a new fit
for purpose gravity / carbon-in-leach (CIL) processing facility with a nameplate capacity of 2.4 million
tonne per annum. The new facility will include a three-stage crushing circuit and will be constructed in
the existing mill location so that it aligns with previous processing approvals. The cost of demolishing
and removal of the existing plant was estimated by Demex, and the design, cost and timeline to
construct the processing plant were estimated by Sedgman Pty Ltd (Sedgman).
9
Processing throughput varies between 2.2Mtpa and 2.4Mtpa depending on the ore feed material
hardness. Comminution, reagent consumption and metallurgical recoveries for ore sourced from the
Project are derived from metallurgical testwork conducted by ALS Metallurgy, a 2012 CPC Engineering
desktop study and site operating records. Sedgman’s process design work used an abrasion index of
0.25g, a bond rod work index of 21kWh/t and a bond ball work index of 19kWh/t.
Metallurgical sighter test-work has been completed on all 14 deposits included in the Study at a grind
size of 80% passing 75μm. An average gravity gold recovery of ~35% was returned from the 14 ore
sources. A review of relevant metallurgical reports and test results by Sedgman noted that the free
milling ore showed rapid leach kinetics with most of the leaching being completed within 8 hours and
totally complete in under 24 hours. Sedgman stated an expected weighted average total circuit
recovery of 94.5%. Average Life of Mine (LOM) gold recoveries estimated from monthly Gidgee Gold
Mine production reports from 1987 to 2005 were 93.0% which supports the Sedgman metallurgical test
work review average recovery estimate. Sedgman’s process design used a leach residence time of 6
hours, an adsorption residence time of 18 hours, an average sodium cyanide consumption of 0.39kg/t
and a lime consumption of 0.54kg/t for process design work. Further metallurgy and comminution test
work will feature in the Company’s ongoing economic studies.
ECG Engineering recommended that power should be derived from a mixed solar and LNG generating
facility supplied on a Build-Own-Operate (BOO) basis by an independent power producer under a price
per kWhr contract.
Tailings Storage
The Company plans to use the existing Tailings Storage Facility (TSF) and continue with upstream
raising of the perimeter embankment, but simultaneously develop a new TSF immediately north of the
existing TSF to achieve the required LOM tailings storage capacity. The footprint area of the existing
TSF will not increase, and the new northern TSF’s footprint will cover an area of approximately 70 ha.
The two TSF’s will be operated separately with tailings deposition alternating between the two facilities.
Water Supply, Dewatering and Water Management
Groundwater in the main mining area (Swan/Swift/Kingfisher) consistently reports good water quality
(low Total Dissolved Solids) and is suitable for mineral processing and stock drinking water, meeting
the Australian and New Zealand Environment Conservation Council (ANZECC) stock drinking water
guidelines.
Dewatering and water management will be required throughout the LOM and is necessary for 10 of the
14 deposits included in the Study. Dewatering will be required to commence 3 months prior to the
commencement of mining. Initial dewatering will consist of pumping the Swan / Swift pit water to the
Kingfisher and Hawk pits approximately 3km to the south of the old Gidgee processing facility. A lateral
pipeline will be provided to supply raw water to the processing plant.
Water stored during pre-production in the Kingfisher and Hawk pits will be used to supply raw water to
the process plant when production commences. The Heron to Manikato pits will be dewatered by
pumping water to the Kingfisher pit, and the Toedter pit will be dewatered by pumping to the Kearrys
pits 3 kilometres to the east.
Dewatering records for pits near the Gidgee processing plant during the previous production periods
provide a high level of confidence around expected groundwater inflow rates. These flow rates have
been used to determine pumping requirements for pit dewatering in the area and have been costed
10
into pre-production costs, sustaining capital costs, and ongoing operating costs. Water flow information
is limited for the areas to the north and south of the main Gidgee mining area. In these areas estimated
water flow rates used are of low confidence and further hydrogeology and water flow work is planned.
Infrastructure
The centre of the Project is located 80km north of Sandstone. Access from Sandstone to the old Gidgee
processing plant is via a 20m wide gravel road that is very well maintained by the Sandstone Shire.
Historic haul roads between 15m and 20m wide extend for ~20 kilometres to the south of the Gidgee
plant to the Manikato deposit, and for ~50 kilometres to the north of the plant to the Toedter deposit.
The sandstone shire is occasionally contracted to grade the Project haul roads.
The old Gidgee processing facility, TSF, and local Waste Rock Dumps (WRD) are located within
M57/634 which is a large mining lease (4,810Ha) with ample room for additional mining and/or
processing related infrastructure. All other mining leases containing resources within the mine
production target have ample room for WRD’s.
The old Gidgee mine camp is still functioning
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