Overview
| Stage | Production |
| Mine Type | Open Pit |
| Commodities |
|
| Mining Method |
|
| Processing |
- Gravity separation
- Counter current decantation (CCD)
- Concentrate leach
- Carbon in leach (CIL)
- Merrill–Crowe
- Cyanide (reagent)
|
| Mine Life | 4 years (as of Jan 1, 2020) |
Source:
p. 129
The mine is 100% owned and managed by Harmony through Moroke Consolidated Goldfields.
Deposit Type
- Breccia pipe / Stockwork
- Vein / narrow vein
Summary:
The deposit is a structurally controlled vein stockwork gold-silver deposit located in the Morobe Granodiorite of the Wau Graben. Gold silver mineralisation is contained in carbonate-adularia-quartzsulphide vein stockworks and in a few instances in hydrothermal breccias. Discrete zones of intense stockwork fracture and mineralised veining comprise individual lodes. At the Hidden Valley deposit gold and silver are related to steeply dipping (Kaveroi Creek Zone) and flatlying (Hidden Valley Zone) sheeted vein swarms associated with an underlying shallow thrust.
Summary:
Mining operations occur in two open pits 6km apart, Hidden Valley and Hamata of which Hidden Valley is the largest. Both mines employ conventional open pit mining techniques with back-hoe excavators and rigid dump trucks as the primary load and haul equipment. Front-end loaders are used for crusher feed and stockpile reclaim. A number of articulated smaller dump trucks are used for construction, and to a lesser extent mining in Hamata.
Mining bench configuration consists of 18m inter-berm heights, mined as 3m x 6m benches of 2m x 3m flitches (in ore).
Waste is disposed of in engineered valley fill waste dumps, with toes keyed in and buttressed using competent non-acid producing rock. The waste is captured in the valley fill Western Sector and Niekywe waste dumps. Underdrains and toes have been constructed and now provide sufficient capacity for the life of mine waste.
Processing
- Gravity separation
- Counter current decantation (CCD)
- Concentrate leach
- Carbon in leach (CIL)
- Merrill–Crowe
- Cyanide (reagent)
Source:
Summary:
A crushing facility is located near the Hidden Valley pit with the crushed ore conveyed via a 3.8km long overland pipe conveyor. Ore from the Hamata pit is trucked to the Hamata crushing station, located next to the ore processing plant.
The Hidden Valley process plant was designed to treat nominally 4.1Mtpa of gold/silver bearing ore. The process uses a two stage crushing circuit followed by a SAG mill, gravity, CCD/Merrill Crowe circuit for silver and a carbon-in-leach circuit for the gold. A silver/gold ore bar is produced and flown off site for refining and sale.
Tailings are disposed of in a terrestrial tailings storage facility located to the south-west of the process plant. Dam-wall construction of the tailings storage facility is ongoing and largely constitutes placement of suitable oxide and fresh competent material sourced from mining in the Hamata pit and nearby quarry. The processing inventory in this ore reserve estimate is constrained by the remainin ........
Recoveries & Grades:
| Commodity | Parameter | 2019 | 2018 | 2017 | 2016 | 2015 |
|
Gold
|
Head Grade, g/t
| 1.6 | 1.36 | 1.07 | 1.51 | 1.84 |
|
Gold
|
Recovery Rate, %
| | | | ...... | ...... |
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Reserves at June 30, 2018:
| Category | Tonnage | Commodity | Grade | Contained Metal |
|
Proven
|
1.9 Mt
|
Gold
|
0.92 g/t
|
56 koz
|
|
Proven
|
1.9 Mt
|
Silver
|
19.61 g/t
|
1,193 koz
|
|
Probable
|
23.3 Mt
|
Gold
|
1.62 g/t
|
1,215 koz
|
|
Probable
|
23.3 Mt
|
Silver
|
32.12 g/t
|
24,083 koz
|
|
Proven & Probable
|
25.2 Mt
|
Gold
|
1.57 g/t
|
1,271 koz
|
|
Proven & Probable
|
25.2 Mt
|
Silver
|
31.18 g/t
|
25,276 koz
|
|
Measured
|
1.9 Mt
|
Gold
|
0.92 g/t
|
56 koz
|
|
Measured
|
1.9 Mt
|
Silver
|
19.61 g/t
|
1,193 koz
|
|
Indicated
|
81.7 Mt
|
Gold
|
1.44 g/t
|
3,779 koz
|
|
Indicated
|
81.7 Mt
|
Silver
|
27.5 g/t
|
72,256 koz
|
|
Inferred
|
3 Mt
|
Gold
|
1.18 g/t
|
113 koz
|
|
Inferred
|
3 Mt
|
Silver
|
29.21 g/t
|
2,791 koz
|
|
Total Resource
|
86.6 Mt
|
Gold
|
1.42 g/t
|
3,948 koz
|
|
Total Resource
|
86.6 Mt
|
Silver
|
27.38 g/t
|
76,240 koz
|
Commodity Production Costs:
| | Commodity | Units | 2019 | 2018 | 2017 | 2016 | 2015 |
|
Cash costs
|
Gold
|
USD
|
|
......
|
1,252 / oz
|
1,320 / oz
|
1,230 / oz
|
|
Cash costs
|
Gold
|
USD
|
...... †
|
...... †
|
1,068 / oz†
|
1,028 / oz†
|
1,065 / oz†
|
|
All-in sustaining costs (sold)
|
Gold
|
USD
|
|
......
|
1,417 / oz
|
1,564 / oz
|
1,557 / oz
|
|
All-in sustaining costs (sold)
|
Gold
|
USD
|
...... †
|
...... †
|
1,241 / oz†
|
1,282 / oz†
|
1,395 / oz†
|
† Net of By-Product.
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Operating Costs:
| | Units | 2017 | 2016 |
|
Total operating costs ($/t milled)
|
USD
| 33 | 39 |
Financials:
| | Units | 2019 | 2018 | 2017 | 2016 | 2015 |
|
Capital expenditures
|
M USD
| ...... | ...... | ...... | ...... |
62
|
|
Revenue
|
M USD
| ...... | ...... | ...... | ...... |
272
|
|
Gross profit
|
M USD
| ...... | ...... | ...... | |
|
|
EBIT
|
M USD
| | | | ...... |
-28
|
|
EBITDA
|
M USD
| | | | ...... |
26
|
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