Overview
Stage | Preliminary Economic Assessment |
Mine Type | Open Pit |
Commodities |
|
Mining Method |
|
Processing |
- Smelting
- Electric furnace
- Heap leach
- Merrill–Crowe
- Cyanide (reagent)
|
Mine Life | 10.8 years (as of Jan 1, 2015) |
Source:
p. 2
American Gold is a corporation incorporated under the laws of Nevada, USA and is a wholly-owned subsidiary of Gunpoint, a corporation incorporated under the laws of BC, Canada.
Deposit Type
- Epithermal
- Vein / narrow vein
Summary:
The mineralization was divided into the following domains, separated by north-northwest fault, for the purpose of resource modelling.
Bear Creek Hanging-Wall Vein System/Domain, bounded by Ripper Fault to south and Cabin Fault to north. The Hanging-Wall vein is comprised predominantly of massive white sulphide poor silica with typical low- sulfidation epithermal textures, including recrystallization, coliform and crustiform banding, adularia bands, amethyst, etc.
Bear Creek Footwall Vein System/Domain, bounded by Cabin Fault to south and Talapoosa (South) Fault to the north. The Footwall vein is more sulphide rich, associated with a number of gangue phases including, red hematitic silica, chlorite and minor white to clear silica.
Main Zone Vein System/Domain bounded by Talapoosa (South) Fault to the south and Opal/Dyke Fault to the north.
The mineralization at both Dyke Adit and East Hill shows similarities in appearance and texture to that of the Hanging-Wall Zone at Bear Creek.
The modelling of veins and their bounding faults indicates that the general trend of all mineralization is around 115°, with two prominent dip angles:
- Steeply-dipping veins at approximately 70° south, for the Hanging-Wall and Footwall Zones at Bear Creek and for the eastern-most portion of the Main Zone.
- Shallowly-dipping veins, at approximately 20 to 40° south for the Dyke Adit, northwest part of the Main Zone (north) and the East Hill Vein. At least in the Main Zone, the flattening of vein dip could be the result of dilatational zones developed between the Talapoosa and Dyke Faults. In the case of the Dyke Adit and East Hill veins the attitude of the veining appears to parallel that of the contact between the hornblende andesite porphyry and the adjacent unit.
Summary:
The mine design consists of three mining areas: the Main Pit, Dyke Adit, and the East Hill Pit. Under the current analysis, the Main Pit and Dyke Adit combine into one open pit instead of two separate pits. Approximately 90% of production is from the Main Pit area, with 7% from the Dyke Adit area, and the remaining 3% from the East Hill area.
The overall strip ratio is 1.47 units of waste to each unit of mineralized material production.
Waste rock storage areas will be located toward the northeast and southwest sides of the pit areas in as close proximity as possible to the mining areas so as to minimize waste haulage distances. These areas were sized to store a combined 90Mt of waste rock.
Industry standard surface mining techniques formed the basis of mine production. This Base Case Scenario used CAT 992 – 16.5 yd3 wheel loaders and CAT 777 100st trucks as production prime movers.
Flow Sheet:
Crusher / Mill Type | Model | Size | Power | Quantity |
Jaw crusher
|
|
|
|
1
|
Cone crusher
|
|
|
|
1
|
Summary:
Primary crushing
A large jaw crusher was selected as the primary crusher to match production needs and rock hardness. Mineralized material mined within the PEA pit shell will be dumped into a pocket above a vibrating grizzly screen. Oversize will move by gravity and shaking action over the grizzly bars to feed the jaw. Coarse material, having been crushed by the jaw, will discharge and combine on the same conveyor belt with undersize material that passed through the grizzly bars. Crushed material will be stacked in a 3,000-ton live capacity primary crushed stockpile.
Secondary crushing
Primary crushed material will be extracted from under the stockpile by an apron feeder housed in a steel reclaim tunnel and will be transferred to a conveyor that feeds a vibrating secondary screen above the secondary heavy-duty standard cone crusher. Coarse material that does not pass the screen will discharge into a day-bin above the cone crusher. The coarse material will be crushed, combined with fines that passed the secondary screen and stacked in a 3,000-ton live capacity secondary crushed stockpile.
HPGR crushing
Product from secondary crushing and screening will be extracted from under the stockpile by a vibrating pan feeder housed in a steel reclaim tunnel and transferred to a conveyor that feeds a day bin. A vibrating pan feeder delivers material to the high pressure grinding roll (HPGR). HPGR discharge is screened on twin – double deck screens to remove the fine product. Coarse material that does not pass the screen will discharge back into the day-bin above the HPGR to be combined with fresh feed material. A nominal 10-mesh product will be collected on a conveyor belt and stacked in a 3,000-ton live capacity HPGR crushed stockpile.
Processing
- Smelting
- Electric furnace
- Heap leach
- Merrill–Crowe
- Cyanide (reagent)
Flow Sheet:
Summary:
Gold and silver from the Talapoosa deposits will be recovered using industry standard heap leach cyanidation and gold precipitation techniques.
Resource material within the PEA pit shell as delivered from the mine will be crushed, agglomerated, and stacked on a heap. Cyanide leach solution will be distributed over the stacked heap and percolate through the material. Leach solution containing the gold and silver (pregnant solution or “preg-solution”) will collect at the base of the heap in the overliner-piping network and flow into the preg-pond.
Preg-solution will be pumped to plate and frame clarifying filters in the plant. Clarified preg-solution is deaerated and combined with zinc powder and lead nitrate immediately before being pumped into plate and frame precipitation filters. Gold and silver, both being substantially more nobel metals than zinc, will precipitate out of solution while the zinc powder will go into solution. Lead nitrate is a minor (often not ........

Recoveries & Grades:
Commodity | Parameter | Avg. LOM |
Gold
|
Recovery Rate, %
| 66 |
Gold
|
Head Grade, oz/ton
| 0.02 |
Silver
|
Recovery Rate, %
| 52.5 |
Silver
|
Head Grade, oz/ton
| 0.34 |
Projected Production:
Commodity | Units | Avg. Annual | LOM |
Gold
|
koz
| 55 | 593 |
Silver
|
koz
| ......  | ......  |
All production numbers are expressed as metal in doré.
Operational Metrics:
Metrics | |
Stripping / waste ratio
| 1.47 * |
Waste tonnes, LOM
| 61,023 k tons * |
Total tonnes mined, LOM
| 102,444 k tons * |
Tonnes milled, LOM
| 41,420 k tons * |
Annual processing rate
| 3.8 M tons * |
Annual mining rate
| 3.8 M tons of ore * |
* According to 2015 study.
Reserves at March 24, 2015:
Mineral Resource reported at 0.013 oz/ton gold cut-off.
Category | Tonnage | Commodity | Grade | Contained Metal |
Measured
|
17,170,870 tons
|
Gold
|
0.036 oz/ton
|
618,468 oz
|
Measured
|
17,170,870 tons
|
Silver
|
0.494 oz/ton
|
8,489,086 oz
|
Indicated
|
14,093,600 tons
|
Gold
|
0.028 oz/ton
|
394,334 oz
|
Indicated
|
14,093,600 tons
|
Silver
|
0.366 oz/ton
|
5,160,273 oz
|
Measured & Indicated
|
31,264,470 tons
|
Gold
|
0.032 oz/ton
|
1,012,802 oz
|
Measured & Indicated
|
31,264,470 tons
|
Silver
|
0.437 oz/ton
|
13,649,358 oz
|
Mine Management:
Job Title | Name | Phone | Ref. Date |
.......................
|
.......................
|
.......................
|
Mar 30, 2022
|
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