Overview
| Stage | Production |
| Mine Type | Open Pit |
| Commodities |
|
| Mining Method |
|
| Processing |
- Heap leach
- Counter current decantation (CCD)
- Carbon in column (CIC)
- Cyanide (reagent)
|
| Mine Life | 8 years (as of Jan 1, 2016) |
Source:
p. 43
Deposit Type
- Carlin-type
- Sediment-hosted
Summary:
Long Canyon is a sediment-hosted disseminated gold deposit.
The gold mineralization at Long Canyon is best described as sediment-hosted, Carlin-type gold mineralization.
The mineralization identified at Long Canyon shares many of the characteristics of Carlin-type gold mineralization, including:
• Stratigraphic control on mineralization - mineralization is hosted primarily in limestone, particularly in silty, thin-bedded units;
• Structural control on mineralization - mineralization occurs in karstic cavities, collapse breccias, and anticlinal fold hinges;
• Geochemical association - elevated arsenic, mercury, antimony, and thallium accompany the gold mineralization, while silver and base-metal concentrations are low; and
• Alteration - mineralization is associated with decalcification, silicification/jasperoid, oxidized variants of pyrite and arsenical pyrite or arsenopyrite, and clay alteration.
The Long Canyon project also displays some characteristics that are unlike typical Carlin-type gold deposits. The prevalent association of hematite with gold mineralization at Long Canyon is not a common characteristic among all Carlin-type deposits, although this phenomenon is associated with weathered/oxidized portions of some of the deposits.
Summary:
The Long Canyon available mining fleet consists of two shovels and twelve 240-ton haul trucks.
Commercial production at Long Canyon was achieved in November 2016.
Processing Technologies
- Heap leach
- Counter current decantation (CCD)
- Carbon in column (CIC)
- Cyanide (reagent)
Flow Sheet:
Summary:
Oxide ore with suitable cyanide solubility is treated on a heap leach pad.
Long Canyon is permitted to process up to 5 million tons of ore annually, with developments that consist of:
* an open pit;
* a heap leach facility (HLF);
* a carbon-in-column (CIC) plant;
* a waste rock storage facility (WRSF); and
* support facilities including a truck shop and administration building.
A dilute sodium cyanide solution is applied to the stacked ore on the high-density polyethylene (HDPE) lined leach pads. Pregnant solution from the leach pads is collected in perforated piping under the leach pad, and reports to main collection headers that lie in a HDPE-lined Solution Collection Channel along the edge of the heap leach pad. The collection headers report to a Pregnant Solution Tank (PST), and a Process Solution Pond (PSP) is available for solution in case of upset plant operating conditions. The PSP has a total capacity of 17.4 million gallons, and ........
Production:
| Commodity | Units | 2018 | 2017 | 2016 | Avg. Annual (Projected) |
|
Gold
|
koz
| ...... | 174 | 22 | 125 |
All production numbers are expressed as metal in doré.
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Operational Metrics:
| Metrics | 2017 |
|
Annual processing capacity
| ...... |
Reserves at December 31, 2018:
| Category | Tonnage | Commodity | Grade | Contained Metal |
|
Proven
|
600 kt
|
Gold
|
2.18 g/t
|
50 koz
|
|
Probable
|
21,700 kt
|
Gold
|
1.31 g/t
|
920 koz
|
|
Proven & Probable
|
22,300 kt
|
Gold
|
1.34 g/t
|
970 koz
|
|
Measured
|
500 kt
|
Gold
|
3.84 g/t
|
60 koz
|
|
Indicated
|
14,000 kt
|
Gold
|
3.5 g/t
|
1,570 koz
|
|
Measured & Indicated
|
14,500 kt
|
Gold
|
3.52 g/t
|
1,630 koz
|
|
Inferred
|
5,600 kt
|
Gold
|
1.94 g/t
|
350 koz
|
Heavy Mobile Equipment as of December 31, 2018:
| HME Type | Size | Quantity |
|
Shovel (hydraulic)
|
|
2
|
|
Truck (haul)
|
240 tons
|
12
|
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