Name of the Project
Bibiani gold project.
Location
Ghana.
Project Owner/s
Asante Gold concluded the $90-million transaction to buy Bibiani, in Ghana, from Australia’s Resolute Mining in August 2021.
Project Description
The Bibiani project has an initial ore reserve of 5.4-million tonnes grading 3.7 g/t containing 640 000 oz of gold and mineral resources of 1.9-million tonnes grading 3.6 g/t for 1.1-million ounces of gold.
Resolute aims to re-establish an underground mine at the project.
A feasibility study has confirmed a viable development pathway and contemplates the production of up to 1.2-million tonnes a year from longhole, open stope underground mining.
The stope will be started through a slot raise at one end of the ore drive and then mined by progressively firing the drill rings and retreating along strike.
Level designs will comprise:
- main level access, excavated 5.5 m wide and 5.5 m high, with an arched profile;
- footwall drives, excavated 5.5 m wide and 5.5 m high;
- crosscuts and ore drives, designed to fit longhole drills and loaders;
- stockpiles for storing stope ore, ready for truck loading and placed every 150 m along the footwall drive; and
- a sump, placed in the main level access and linked to the lower levels through a drain hole.
The study proposes mining 100 000 t a month of ore, with about 25 000 t a month of waste providing total rock movement of 125 000 t a month.
Ore processing will occur at the existing Bibiani processing plant.
A review of the current ore treatment plant at Bibiani and the results of testwork to date have been used to develop an effective processing flowsheet to achieve satisfactory recovery. Gold is predominantly fine and occurs along edges or cracks in pyrite and arsenopyrite sulphide minerals.
The process design produces a sulphide concentrate by flotation at a primary grind size of P80 106 μm. Concentrate is fine-ground to P80 25 μm before cyanidation. The flotation tails are also cyanide leached, while carbon-in-leach (CIL) recovers the gold.
Key process design parameters include:
- primary crushing to P80 of 120 mm;
- milling, using the existing semiautogenous mill operation in single-stage, closed circuit and producing a product size of P80 106 μm;
- flash flotation to a target mass pull of 2%;
- scavenger flotation, which, together with the flash flotation concentrate, recovers a total combined concentrate of 93% gold, 98% sulphides and 60% organic carbon into a concentrate mass that comprises 10% of new feed;
- concentrate regrind; and
- leaching of concentrate in a CIL circuit.
Gold production is expected to be maintained at an estimated 100 000 oz/y, which will sustain a five-year mine life on the initial ore reserve.
Potential Job Creation
The project will employ up to 300 people, including subcontractors, over its nine-month duration.
Net Present Value/Internal Rate of Return
Not stated.
Capital Expenditure
Preproduction capital expenditure is estimated at $75-million.
Planned Start/End Date
Asante Gold poured first gold at its Bibiani gold mine in July 2022.
The processing plant was commissioned in early June 2022, while 24-hour daily operation started on July 1, 2022, including CIL stripping, with elution areas now operating.
Latest Developments
Asante Gold has extended the mineral resource estimate of Grasshopper pit, where mining started earlier this year.
The Grasshopper pit on the Bibiani mining lease is less than 2 km from the processing plant.
Supported by about 10 000 m of historical drilling and 8 800 m of recent drilling, Asante has reported a constrained indicated resource of 1.88-million tonnes at 1.04 g/t for 56 500 oz of contained gold for the Grasshopper pit.
The majority of the mineralised material in the Grasshopper pit is within the oxide transition zone, with anticipated gold recovery exceeding 90% and a haulage distance of less than 2 km to the process plant.
Further, the presence of multiple shoots of mineralisation along strike and down plunge beyond the existing pit shell has highlighted the promising opportunities for sustained expansion, president and CEO Dave Anthony has said.
Contact Details for Project Information
Asante Gold, tel +1 604 558 1134 or email info@asantegold.com.