Vancouver — With political uncertainty in Indonesia forcing a suspension of field work on its Halmahera nickel-cobalt property in Indonesia, Weda Bay Minerals (WDA-T) hopes to improve the project economics by incorporating the saprolite resources on the promising laterite project.
The latest metallurgical tests confirm that the saprolite resources can be mined in unison with the limonite reserves. Recoveries from the saprolite hit up to 95% for both nickel and cobalt.
The junior is considering two approaches to utilizing the saprolite ore. The first is to use it to neutralize excess acid in the high-pressure acid-leach (HPAL) pulp, reducing the need for limestone in recovering the metals. The second approach is to undertake direct atmospheric leaching in a separate circuit.
The metallurgical results are being used to revise the prefeasibility study, which is aimed at lowering the capital costs for the project.
The original study was completed by Kvaerner Process (Australia) and Hatch Associates. It concluded that the project is robust at varying capital costs and production levels. The base-case scenario is 48,500 tonnes nickel and 4,600 tonnes cobalt over 20 years.
The study envisions peak production occurring in years three-to-five years. In each of these years, 52,600 tonnes nickel and 5,1000 tonnes cobalt would be produced. Operating costs, exclusive of cobalt credits, are pegged at US97 per lb. nickel.
In July, the company stopped field work on the project after its major shareholder and project financier voiced concerns about business uncertainty in the country.
The OM Group (OMG-N), with a 19.9% stake in Weda Bay, decided to stop advancing funds for the nickel laterite project. The company believed that, under current market conditions, project financing to put the deposit into production would be difficult to raise.
As a result, the Halmahera project has been put on care and maintenance.
Weda Bay was drilling the deposit in order to move the bulk of the resource from the indicated to the measured category. At last count, the company pegged the indicated resource at 66 million tonnes grading 1.4% nickel and 0.09% cobalt. The upper, limonitic portion contains 41 million tonnes of 1.2% nickel and 0.16% cobalt with a magnesium oxide content of 4.5%.
Overall, the property hosts an indicated resource of 133 million tonnes grading 1.4% nickel and 0.1% cobalt. Additional inferred resources are estimated at 70 million tonnes of 1.29% nickel and 0.14% cobalt, giving an aggregate resource estimate of 204 million tonnes of 1.37% nickel and 0.11% cobalt.
This resource is contained in 11 target areas — SM, Area 2, Uniuni Hill, Tarzan Hill, Sake River, Sake River West, Lipe River, Jira River, Casuarina, Orchid and Big Kahuna.
Weda Bay was moving towards a bankable feasibility study. The US$18-million study was being funded by the OM Group.
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