Overview
Stage | Pre-Feasibility |
Mine Type | Open Pit |
Commodities |
|
Mining Method |
|
Processing |
- Calcining
- Carbon re-activation kiln
- Smelting
- Agitated tank (VAT) leaching
- Carbon in leach (CIL)
- Elution
- Solvent Extraction & Electrowinning
- Cyanide (reagent)
|
Mine Life | 5 years (as of Jan 1, 2020) |
On the 1st May 2021, White Rock executed a definitive agreement with Thomson Resources Ltd (“Thomson”) (ASX:TMZ) for a 3 stage earn-in and option to joint venture agreement (“JVA”) at Mt Carrington. The definitive agreement allows Thomson to earn up to 70% of White Rock’s Mt Carrington gold - silver project ("Project").
White Rock is free-carried through the earn-in period of the JVA. Thomson assumes management of the Project and has sole responsibility for keeping the Project in good standing and funding all of the site care and maintenance costs until the formation of the JVA. Once the earn in is complete, at whichever stage, a joint venture is formed for the future development and operation of the Project. Funding for the Development of the Project through to commercial production will be on a prorata basis. |
Latest News | White Rock Minerals: Mt Carrington Gold-Silver Project Pre-Feasibility Study Stage 1 December 27, 2017 |
Source:
p. 23
The Mt Carrington Project comprises 22 Mining Leases and one Exploration Licence. All tenements are held 100% by White Rock (MTC) Pty Ltd, a wholly owned subsidiary of White Rock Minerals Ltd. No farm-in or farm-out agreements are applicable. The Mt Carrington Project is subject to a binding 3 stage Earn-In and Option to Joint Venture Agreement with Thomson Resources Ltd.
Deposit Type
- Epithermal
- Vein / narrow vein
- Breccia pipe / Stockwork
Summary:
The Mt Carrington deposits are hosted by the Drake Volcanics; a NW-trending 60km x 10km Permian bimodal volcano-sedimentary sequence within the Wandsworth Volcanic Group near the north-eastern margins of the southern New England Fold Belt.
The Drake Volcanics overlie or is structurally bounded by the Carboniferous to Early Permian sedimentary Emu Creek Formation to the east and bounded by the Demon Fault and Early Triassic Stanthorpe Monzogranite pluton to the west. The sequence is largely dominated by andesite and equivalent volcaniclastics, however basaltic through to rhyolitic facies stratigraphic sequences are present, with numerous contemporaneous andesite to rhyolite sub-volcanic units intruding the sequence. The Razorback Creek Mudstone underlies the Drake Volcanics to the east, and Gilgurry Mudstone conformably overlies the Drake Volcanic sequence. In addition, Permian and Triassic granitoid plutons and associated igneous bodies intrude the area, several associated with small scale intrusion-related mineralisation. The Drake Volcanic sequence and associated intrusive rocks are host and interpreted source to the volcanogenic epithermal Au-Ag-Cu-Pb-Zn mineralisation developed at Mt Carrington. The majority of the Drake Volcanics and associated mineralisation are centred within a large scale circular caldera with a low magnetic signature and 20km diameter.
The Strauss and Kylo deposits are low sulphidation epithermal vein type mineralisation that manifests as a zone of stockwork fissure veins and vein breccia associated with extensive phyllic to silicic alteration. Veining is localised along the margins of an andesite dome/plug and lava flow within a sequence of andesitic volcaniclastics (tuffaceous sandstone and lapilli tuff). Economically mineralisation is Au-dominant with minor Ag and significant levels of Zn, Cu & Pb.
Mineralisation at Strauss occurs as a broad zone of stockwork veining that narrows with depth. Within the stockwork zone there are two dominant vein orientations: near vertical north trending veins and bedding parallel veins striking north-east and dipping approximately 20° towards the southeast. Recent drilling intersected the vertical veining at 20° to 40° and the bedding parallel veining at 70° to 90°. The mineralisation at Strauss strikes NNE to SSW and extends approximately 360 m in this direction, with a vertical extent in excess of 130 m. The across strike extents of the mineralisation is approximately 200 m.
Mineralisation at Kylo North occurs as a broad zone of stockwork veining that is dominated by near vertical north trending veins focused on the near vertical north trending andesite-volcaniclastic contact. Most drilling typically intersected mineralisation at approximately 20° to 40°. The mineralisation wraps around the eastern edge of the porphyry with a change in strike to NNE-SSE and a steep dip to the west. The mineralisation extends up to 140m along strike with a similar dip extent (140m). Widths range from 2 – 5 m true thickness at the down dip extensions of the mineralisation to in excess of 90 m in the upper parts of the deposit.
Mineralisation at Kylo West occurs as two parallel zones of stockwork veining that strike east-west and dip 70° towards the south. Most drilling typically intersected mineralisation at approximately 30° to 70°. The mineralisation is comprised of two subparallel zones striking E-W with a steep southerly dip, related to a porphyry intrusive contact. The main mineralised zone has a strike length in excess of 300m, with a dip extent of up to 150m. The mineralised zone varies from 2m to in excess of 40m true width, with much of the mineralisation being between 10 – 20m wide.
Summary:
Slope parameters of 8m bench height is selected. The pit optimisations and pit designs were developed without considering the value of Inferred material to determine the ultimate pit limits. However, there is a relatively small amount of Inferred material that is within the final pit limits (approximately 12% of the total mill feed inventory).
The Whittle optimisations have resulted in the merging of the three deposits into a single final pit. However, there is still a starter pit for each deposit.
It is envisaged that a mining contractor will carry out the mining activities with technical and management direction from White Rock. The mine is planned to be operated over three discrete open pits each incorporating drill and blast, load and haul, and ore and waste management tasks.
The initial six-month pre-strip is also required before a continuous ex-pit ore supply can be assured. There is an historic low-grade stockpile from the previous mining operations (1987-1990) which requires removal as soon as practicable in order to help improve acid rock drainage management at the site. This historic low-grade stockpile material will be reclaimed and processed during the commissioning phase of the process plant. It is envisaged that reclaiming of this stockpile will commence about 3-4 months after the start of the pre-strip mining. The annual planned ore production rate of 1.0 Mtpa can be sustained for the full mine life, however this includes the Inferred mineralisation (excluding the pre-exiting low grade stockpile). The Inferred mineralisation totals 12% of the mined plant feed of which the majority is in the last 18 months of the mine life.
The mine production ore is initially sourced from the Kylo West and Kylo North starter pits to ensure access can be maintained before Strauss mines through the pre-existing road. The merging of the three mining areas occurs in the third year of mining and careful planning is required to ensure Kylo West is completed before Kylo North advances too deep, as this pit mines through the ramp into Kylo West.
Flow Sheet:
Crusher / Mill Type | Model | Size | Power | Quantity |
Jaw crusher
|
|
|
|
1
|
Cone crusher
|
|
|
|
2
|
Ball mill
|
|
|
|
1
|
Summary:
The processing plant design is based on conventional, well-proven processing technology following a processing route of:
- Primary crushing by a jaw crusher to a product size P80 of 100mm direct feeding a sizing screen.
- Sizing screen oversize and middlings feeding Secondary and Tertiary cone crushers respectively to a product size of P80 of 10mm.
- Crushed fine ore storage bin.
- Grinding using a single stage Ball mill and classification circuit to a product size of P80 of 75µm.
Processing
- Calcining
- Carbon re-activation kiln
- Smelting
- Agitated tank (VAT) leaching
- Carbon in leach (CIL)
- Elution
- Solvent Extraction & Electrowinning
- Cyanide (reagent)
Flow Sheet:
Summary:
The processing plant will be designed at a nominal throughput of 1 Mtpa of fresh ore. The plant will be designed to operate seven days per week at a nominal treatment rate of 124 dry tonnes per hour of fresh ore.
Over the initial Gold First 5 year mine life, approximately 4.8 Mt of ore will be processed at an average grade of 1.3 g/t Au and 83% recovery to produce approximately 165,700oz recovered gold as dore.
Historic low-grade stockpile material will be reclaimed and processed during the commissioning phase of the process plant.
The processing plant design is based on conventional, well-proven processing technology following a processing route of:
- Crushing ang Grinding.
- Leaching with cyanide and adsorption onto activated carbon by a six stage carbon in leach (CIL) circuit, acid wash and Pressure Zadra elution in separate columns.
- Cold cyanide washing for copper removal which can be run in the elution column and does not require ........

Recoveries & Grades:
Commodity | Parameter | Avg. LOM |
Gold
|
Recovery Rate, %
| 83 |
Gold
|
Head Grade, g/t
| 1.3 |
Reserves at June 30, 2021:
Gold dominant Mineral Resources have been estimated using a cut-off of 0.5g/t Au except Red Rock, which uses a cut-off of 0.7g/t Au. All silver dominant Mineral Resources have been estimated using a cut-off of 25g/t Ag.
Category | Tonnage | Commodity | Grade | Contained Metal |
Probable
|
4.06 Mt
|
Gold
|
1.33 g/t
|
174 koz
|
Indicated
|
7,950,000 t
|
Gold
|
0.9 g/t
|
230,000 oz
|
Indicated
|
7,950,000 t
|
Silver
|
33 g/t
|
8,493,000 oz
|
Inferred
|
11,294,000 t
|
Gold
|
0.3 g/t
|
122,000 oz
|
Inferred
|
11,294,000 t
|
Silver
|
40 g/t
|
14,778,000 oz
|
Total Resource
|
19,244,000 t
|
Gold
|
0.6 g/t
|
352,000 oz
|
Total Resource
|
19,244,000 t
|
Silver
|
38 g/t
|
23,271,000 oz
|
Proposed Heavy Mobile Equipment as of August 19, 2020:
HME Type | Model | Leased or Contractor |
Truck (dump)
|
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