Overview
Stage | Production |
Mine Type | Underground |
Commodities |
|
Mining Method |
- Longhole stoping
- Cemented backfill
- Paste backfill
|
Processing |
- Gravity separation
- Smelting
- Dry Screening
- Carbon re-activation kiln
- Agitated tank (VAT) leaching
- Carbon in leach (CIL)
- Carbon in pulp (CIP)
- Carbon adsorption-desorption-recovery (ADR)
- Solvent Extraction & Electrowinning
- Cyanide (reagent)
|
Mine Life | 5 years (as of Jan 1, 2020) |
The commencement of processing operations at KOTH in the June Quarter 2022 will provide a more costeffective processing alternative for Darlot ore, repositioning Darlot as a high-grade satellite ore source for KOTH. |
Latest News | Red 5 Identifies High-Grade Resource Expansion Potential At Darlot Underground Mine February 22, 2022 |
Source:
p. 19
Company | Interest | Ownership |
Darlot Mining Company (Pty) Ltd.
(operator)
|
100 %
|
Direct
|
Red 5 Ltd.
|
100 %
|
Indirect
|
Deposit Type
- Vein / narrow vein
- Hydrothermal
- Porphyry
Summary:
• The Darlot lodes are considered to be part of an Archean hydrothermal faultvein deposit with many similar characteristics with other deposits within the Yilgarn Craton, namely host rock type and nature of hydrothermal alteration; however, it is atypical in being relatively flat-lying rather than steeply dipping. Felsic porphyries and lamprophyre intrusions are encountered throughout the deposit. The major host for gold mineralisation is the Mount Pickering Dolerite.
Gold mineralisation is associated with quartz veins and alteration haloes controlled by major D2 and D3 structures or secondary splays and cross-linking structures. The quartz veins are hosted mainly by magnetic dolerite and magnetic quartz dolerite rock types and, to a lesser extent, by non-magnetic dolerite and felsic volcano-sedimentary rock types. Lamprophyre intrusions are present in the area with a variety of orientations. In most cases the lamprophyres are thought to be pre- mineralisation but are an un-favorable host rock for mineralisation and in most cases are barren.
The hanging-wall and footwall veins associated with the Lords Felsics mineralisation typically dip to the North between ~3° and ~10° with the Main Lords structure dipping at around 40° to the NW. The Newlands Fault is also included in the resource and dips to the SE at around 6°, (All azimuths stated above are Darlot Mine Grid referenced)
The Lords Felsics area is yet to be mined, hence the veracity of this estimate is yet to be proven by reconciliation data.
The grade in the ore bodies is controlled by both structure and host lithology, in that typically the best grades are hosted by the Magnetic Dolerite and Felsic intrusions, with comparatively lesser grades observed in the other host rocks such as the non-magnetic dolerite. Consequently, host lithology for lodes was a key factor considered for the estimate.
The deposit has an overall strike length of about 1.75km and a width of about 900 m and extends from about 660m to 1,460 m below the natural surface.
Mining Methods
- Longhole stoping
- Cemented backfill
- Paste backfill
Summary:
The principal mining method used for the underground operation at Darlot is long-hole stoping with cemented paste fill where required, with only a small proportion of stopes expected to be filled with paste. This is a proven mining method at Darlot that is associated with good productivities and reasonable costs. Ground conditions underground at Darlot are good. Mine designs have had 20% planned external dilution applied.
Selected mining method deemed appropriate based on geotechnical advice and previous experience and history at Darlot.
Assumptions have been based on actual mining performance at Darlot with Geotechnical Assessments undertaken over the years to develop a comprehensive ground support and reinforcement regime for conditions encountered at Darlot.
Stopes have been designed based on revenue from individual Service blocks. Where this has not been completed an economic cut-off of 2.3 g/t was applied.
Mining dilution of 10 to 20% has been used to development & stoping respectively.
Average mining recovery factor of 90% is applied based on mining methods.
Minimum stope widths of 1.5m for Longhole stopes.
Designed stopes with greater than 50% inferred blocks are excluded from the reported reserve.
Darlot is an operating underground mine and as such all the required infrastructure is in place and operational. Minor Capital Development will be required to extract all of the ore reserve.
The high-grade Oval West deposit was the primary ore source from the Darlot Gold Mine, with bulk stoping continuing throughout most of FY20. The majority of high-grade stopes at Oval West were largely depleted by the end of the reporting period. [AR, 6/30/2020]
Flow Sheet:
Crusher / Mill Type | Model | Size | Power | Quantity |
Jaw crusher
|
|
|
|
1
|
Cone crusher
|
|
|
|
2
|
Ball mill
|
|
|
|
2
|
Processing
- Gravity separation
- Smelting
- Dry Screening
- Carbon re-activation kiln
- Agitated tank (VAT) leaching
- Carbon in leach (CIL)
- Carbon in pulp (CIP)
- Carbon adsorption-desorption-recovery (ADR)
- Solvent Extraction & Electrowinning
- Cyanide (reagent)
Flow Sheet:
Summary:
Ore from the Darlot underground operation will be processed at the existing nameplate 0.83Mtpa gravity and carbon-in-leach (CIL) processing facility. Metallurgical recovery of 94% has been used, which is in line with historical gold recoveries at Darlot.
The Darlot processing plant is currently operating and is a conventional design.
No additional testwork was undertaken as all the ore reserve is contained within previously mined orebodies which are currently being processed on site.
Recoveries through the Darlot processing plant have averaged 94%.
There have been no deleterious elements identified while processing Darlot ore.
Recoveries & Grades:
Commodity | Parameter | 2021 | 2020 | 2019 | 2018 | 2016 | 2015 |
Gold
|
Recovery Rate, %
| ......  | ......  | ......  | 93.5 | 95.3 | 95.3 |
Gold
|
Head Grade, g/t
| ......  | ......  | ......  | 3.5 | 4.75 | 6.08 |
Reserves at June 30, 2020:
Cut-off grade for reported reserves is 2.0 - 2.3 g/t Au.
Cut-off grades for reported resources are:
underground Darlot - 2.0 g/t Au;
underground Great Western - 1.5 g/t Au;
open-pit Darlot and Great Western - 0.5 g/t Au.
Category | OreType | Tonnage | Commodity | Grade | Contained Metal | Recoverable Metal |
Proven
|
Total
|
11.9 kt
|
Gold
|
2.2 g/t
|
0.8 koz
|
0.8 koz
|
Probable
|
Total
|
2,607 kt
|
Gold
|
2.8 g/t
|
234 koz
|
219 koz
|
Proven & Probable
|
Total
|
2,619 kt
|
Gold
|
2.8 g/t
|
235 koz
|
|
Measured
|
Total
|
78 kt
|
Gold
|
4.2 g/t
|
6 koz
|
|
Indicated
|
Total
|
6,596 kt
|
Gold
|
4 g/t
|
847 koz
|
|
Inferred
|
Total
|
5,077 kt
|
Gold
|
2.6 g/t
|
421 koz
|
|
Total Resource
|
Total
|
11,752 kt
|
Gold
|
3.4 g/t
|
1,273 koz
|
|
Commodity Production Costs:
| Commodity | Units | 2017 | 2016 | 2015 | 2014 |
All-in sustaining costs (sold)
|
Gold
|
USD
|
1,432 / oz†
|
1,238 / oz†
|
1,057 / oz†
|
1,222 / oz†
|
All-in costs
|
Gold
|
USD
|
1,432 / oz†
|
1,238 / oz†
|
1,057 / oz†
|
1,222 / oz†
|
† Net of By-Product.
Financials:
| Units | 2016 | 2015 |
Capital expenditures
|
M USD
|
21.4
|
20
|
Revenue
|
M USD
|
83.1
|
91.3
|
Operating Income
|
M USD
|
11
|
6.3
|
Gross profit
|
M USD
|
25.4
|
32.1
|
HME Type | Model | Size | Quantity | Leased or Contractor | Ref. Date |
Drill (long hole)
|
.......................
|
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Jul 14, 2014
|
Jumbo
|
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Jul 14, 2014
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Loader
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Jul 14, 2014
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Loader
|
.......................
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.......................
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Jul 14, 2014
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Truck (haul)
|
.......................
|
50 t
|
.......................
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Jul 14, 2014
|
Truck (haul)
|
.......................
|
60 t
|
.......................
|
|
Jul 14, 2014
|
Truck (haul)
|
.......................
|
|
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|
|
Dec 31, 2018
|
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