Name of the Project
Shafter silver mine project.

Location
Texas, US.

Client
Aurcana Corp.

Project Description
An updated preliminary economic assessment (PEA) on the Shafter project proposes the reopening of the existing Aurcana underground access ramp and recommissioning of the existing leach-milling operation. Average yearly silver production during the first six years of operation is estimated at 1.5-million ounces. Life-of-mine silver production is estimated at 9.3-million ounces of silver.

The project will have a six-year mine life.

The PEA contemplates an underground mine at Shafter maximising the extensive pre-existing underground development and feeding the modified existing mill at a rate of 600 t/d.

Mining will use conventional mechanised methods.

The total mill throughput in the PEA is estimated at 1.3-million tons, of which
59% are currently classified in the resource estimate as measured and indicated material, and 41% as inferred material.

A 5 oz/t breakeven cutoff grade has been reflected in the underground mine design. The breakeven cutoff incorporates grade, mine and process plant operating costs and recovery data.

The Shafter mine’s processing facility proposed in the PEA will use whole cyanide leach to extract silver from the mill feed. Metal recovery will use a standard Merrill Crowe counter current decantation (CCD) zinc precipitation method.

The slurry from the leach circuit will be transferred to the CCD circuit using four thickeners for cleaning the slurry of pregnant leach solution at an expected efficiency of 96%.

The pregnant solution from the CCD circuit will flow to the deaeration vessel and then to the zinc precipitation circuit.
Cleaned residue from the CCD circuit is pumped to the tailings plate and frame filters for one final wash before the residue cake is conveyed to a tailings load-out area, where it will be hauled to a lined dry stacked tailings storage facility.

The zinc precipitation circuit will mix zinc with silver-bearing pregnant solution causing the silver to precipitate from the solution.

The silver precipitated slurry will be pumped through the zinc precipitation filters to capture the silver as a cake, after which it will be transferred to a retort for drying, and removing any contained mercury that will be collected for removal off site.

Jobs to be Created
Not stated.

Net Present Value/Internal Rate of Return
The project has a base case post-tax net present value, at a 5% discount rate, of $18-million, and an internal rate of return of 40.9%, with a payback of about 1.7 years.

Value
Initial capital costs of have been estimated at $13.2-million, including a $1.1-million contingency.

Duration
Not stated.

Latest Developments
With the release of a positive PEA study, Aurcana believes future work should begin with the rehabilitation of the Shafter ramp, which will allow for the establishment of underground drill stations to start definition drilling.

Key Contracts and Suppliers
None stated.

On Budget and on Time?
Not stated.

Contact Details for Project Information
Aurcana Corp, tel +1 604 331 9333, fax +1 604 633 9179 or email info@aurcana.com.