TORONTO (miningweekly.com) – A revised and updated feasibility study for diamond major De Beers and partner Mountain Province Diamonds’ Gahcho Kué project, located in Canada's Northwest Territories, has confirmed the remote project’s robust metrics.

The feasibility study found that the project, which is a joint venture between Mountain Province (49% interest) and De Beers Canada (51% interest), had a net present value at a 10% discount rate of C$1-billion, with an internal rate of return of 32.6%.

It would cost C$859-million to construct the project, and the operation would require working capital of C$80-million.

Costs to ramp the operation up through to January 2017 were estimated to total C$82-million.

The mine life was estimated at 12 years, over which the operation would produce about 53.4-million carats at an average yearly rate of 4.45-million carats.

The feasibility report, compiled and prepared by JDS Energy, Mining Inc and Hatch, established a sales price target of $149.66/ct.

"The feasibility study revision and update reconfirms an economically robust, technically credible and environmentally sound development plan for the Gahcho Kué mine," Mountain Province CEO Patrick Evans said.

The per carat price was derived from the modelled diamond price estimates provided by WWW International Diamond Consultants (February 2014 price book) exclusive of marketing fees post government valuation. Mountain Province had estimated the average modelled diamond price in 2014 to be $118.38/ct.

The average yearly output for the first three years of full production (2017 to 2019) would be 5.6-million carats.

Mountain Province noted that the ramp-up costs did not take into consideration the revenue expected from the initial production of about a million attributable carats during the early stages between September 2016 through to January 2017.

The Gahcho Kué deposit has current National Instrument 43-101-compliant total proven and probable reserves of 55.5-million carats, contained in 35.4-million tonnes grading 1.57 ct/t.