Overview
Stage | Production |
Mine Type | Open Pit & Underground |
Commodities |
|
Mining Method |
- Truck & Shovel / Loader
- Overhand Cut & Fill
- Underhand Cut & Fill
- Longhole stoping
- Avoca
|
Production Start | ...  |
Mine Life | 9 years (as of Jan 1, 2021) |
The project hosts both high grade open pit and underground mineral resources that remain open for expansion. The fully permitted Granite Creek underground represents the Company's most advanced project. Initial rehabilitation of the underground workings was completed in 2021 and additional levels are now being constructed and multiple levels are being prepared for mining. The test mining with a target of ramping up to production in H1-2022. Initially, material mined from Granite Creek will be trucked for processing at the nearby NGM's Twin Creeks processing facility through the interim processing arrangement that was entered into for processing until the Company's Lone Tree facility is operational. A Preliminary Economic Assessment for the Granite Creek Mine Project was completed in 2021 and a full feasibility study for the open pit project is planned to be completed in H2-2022. |
Source:
p. 34
In April, 2021, i-80 Gold Corp (i-80) through its wholly-owned subsidiary, Premier Gold Mines USA (PGU), acquired Osgood Mining Company LLC (OMC) from Waterton Global Resources Management. OMC being the owner of the Granite Creek Mine Project.
Contractors
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Deposit Type
- Carlin-type
- Sediment-hosted
Summary:
The Property is located on the eastern flank of the Osgood Mountains within the Basin and Range tectonic province of northern Nevada. The Granite Creek Mine occurs within a northeast-trending structural corridor known as the Getchell gold trend. Gold mineralization at the Property is described as a Carlin-type, sedimentary-rock hosted system.
The Property geology comprises a sequence of Cambrian to Ordovician sedimentary rocks that form part of the Osgood Mountain Terrane and the Osgood Mountains. Much of the Property comprises shales, hornfels sedimentary rocks and limestone interbeds of the Preble Formation, and an overlying (or juxtaposed), alternating sequence of limestone, shale, and dolomite with tuffaceous shale and intraformational conglomerates belonging to the Comus Formation. The Preble and Comus Formations have been folded into a broad north-plunging anticline and have been intruded by large Cretaceous granodiorite stocks, resulting in irregular contact metamorphism.
Gold mineralization at the Property is strongly structurally controlled, occurring at favorable sites within a fault network occurring around the eastern edge of the Osgood granodiorite and predominantly within Comus Formation host rocks. Mineralization is commonly associated with the decarbonatization of carbonate rocks and the introduction of silica, fine grained pyrite, arsenian pyrite, and remobilized carbon. Continuity of mineralization is highly variable, ranging from 40 ........

Mining Methods
- Truck & Shovel / Loader
- Overhand Cut & Fill
- Underhand Cut & Fill
- Longhole stoping
- Avoca
Summary:
Mine plans for the resource areas were designed and planned using conventional open pit mining method for the low grade, widely distributed gold. The open pit areas are suitable for phased designs. Mechanized over-hand cut and fill underground mining method for the narrow, high grade deposits. This method was chosen for its ability to mine narrow vein deposits with little dilution and reducing labor cost. The underground area utilizes the previously mined development and includes new development to replace the current access which will be destroyed when the CX pit is mined.
Open Pit
The Granite Creek Mine Project will employ conventional open pit mining techniques using front end loaders and rear dump rigid frame haul trucks. Open pit material will be treated using heap leach or CIL techniques, depending on grade and recovery of the material being processed. The mine plan is designed to deliver an average of 8,500 tonnes of high-grade heap leach material per day from the open pit to the crusher which will then be stacked on the heap leach pad, and 3,000 tonnes per day of CIL material to the mill. The average daily waste production rate over the life of the mine is 80,700 tonnes per day. Waste material would be either placed on waste rock storage facilities (WRSF) or as backfill in previously mined open pits. There are three distinct open pit production areas on the project: B pit, CX pit, and Mag pit. The CX and Mag pits were each designed with three phases, ........

Source:

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Flow Sheet:
Summary:

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Production:
Commodity | Units | LOM (Projected) |
Gold
|
oz
| 1,245,900 |
All production numbers are expressed as metal in doré.
Reserves at May 4, 2021:
Open Pit Mineral resources are reported at a 0.35 g/t cutoff, an assumed gold price of 1,800 $/tr. oz, using variable recovery, a slope angle of 41 degrees, 6% royalty, heap leach processing cost $9.92 per tonne (includes admin), CIL processing cost of $17.63 per tonne (includes admin).
Underground Mineral Resource Cut-off is 5 gpt based on Mining Cost of $100/ton, Process Cost of $106/ton, recovery of 92%, and a gold price of $1600/t. oz.
Mineral resources are reported at a 0.35 g/t cutoff for .
Cut-off is 5 gpt for Underground Mineral Resource.
Category | OreType | Tonnage | Commodity | Grade | Contained Metal |
Measured
|
In-Situ (OP)
|
20,857 kt
|
Gold
|
1.47 g/t
|
988 koz
|
Measured
|
In-Situ (UG)
|
483 kt
|
Gold
|
10.07 g/t
|
156 koz
|
Indicated
|
In-Situ (OP)
|
7,448 kt
|
Gold
|
1.27 g/t
|
304 koz
|
Indicated
|
In-Situ (UG)
|
525 kt
|
Gold
|
10.7 g/t
|
181 koz
|
Measured & Indicated
|
In-Situ (OP)
|
28,306 kt
|
Gold
|
1.42 g/t
|
1,291 koz
|
Measured & Indicated
|
In-Situ (UG)
|
1,008 kt
|
Gold
|
10.4 g/t
|
337 koz
|
Inferred
|
In-Situ (OP)
|
1,531 kt
|
Gold
|
1.26 g/t
|
62 koz
|
Inferred
|
In-Situ (UG)
|
741 kt
|
Gold
|
13.41 g/t
|
319 koz
|
Corporate Filings & Presentations:
Document | Year |
...................................
|
2021
|
...................................
|
2021
|
...................................
|
2021
|
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