Metallurgical firms pursue new ventures

Several metallurgical firms have inked deals with mining companies in order to maximize benefits from processing technologies and expand into new business opportunities.

An agreement between GeoBiotics and Newmont Mining sets the stage for the companies to market each other’s technologies. Newmont has been granted a non-exclusive worldwide licence to use GeoBiotic’s GEOCOAT bio-oxidation technologies for the treatment of gold and base metal ores and concentrates. GeoBiotics, in turn, becomes the exclusive marketing agent for Newmont’s BIOPRO bio-oxidation technology on a worldwide basis. It also was granted a non-exclusive, worldwide licence to use the BIOPRO technology.

Newmont has recovered 34,000 oz. gold to date from its Carlin, Nev., operation using the BIOPRO technology. The major holds a patent on the process, in which sulphide refractory ore is pre-inoculated by agglomerating or spraying it with naturally occurring bacteria that feed on sulphide minerals. The pre-inoculated ore in then placed on a pad where it is further exposed to bacteria and oxidized, allowing for subsequent metals extraction and recovery.

In the GEOCOAT method, a refractory sulphide concentrate (formed by flotation or gravity separation from the refractory ore) is coated on to the surface of a support rock (either ore or barren rock) and stacked in a heap for bio-oxidation. The thin coating of sulphides allows for efficient mass transfer of oxygen and nutrients to and from the bacteria, oxidizing the sulphide minerals. After bio-oxidation, which takes between 30 to 90 days, the concentrate is removed by trommeling or screening and conventionally leached to recover the now-liberated gold. The support rock is recycled or processed, depending on whether it is ore or waste. Recoveries are similar to existing oxidation technologies, with substantial savings of capital costs (up to 70%) and operating costs (up to 60%).

GEOCOAT has been field-tested successfully in Mexico and at the Obuasi operation in Ghana, and is being examined for use in Greece.

A Toronto-based metallurgical firm is also eyeing opportunities for its processing technologies. Under an agreement with a U.S.-based joint venture, Bactech Metallurgical Solutions will complete a scoping study to determine the economics of recovering platinum group metals (PGMs) from large deposits of low-grade nickel-copper sulphides.

Bactech can earn a net smelter return royalty or a participating interest in the Stillwater nickel-copper sulphide project, next to the producing Stillwater PGM mine in Montana, by testing its proprietary bacterial oxidation technology on the ores and engaging in a feasibility study.

The two deposits are owned by Black Rock, a joint venture formed between Chrome Corp. of America and Johanna Minerals to locate and develop mineral deposits with known resources of PGMs.

One deposit has a drill-indicated resource of 130 million tonnes averaging 0.29% nickel, 0.315% copper and 0.03% cobalt, with PGM grades of up to 5.1 grams per tonne.

The second deposit has a drill-indicated resource of 92 million tonnes averaging 0.7% nickel, 0.7% copper and 0.07% cobalt, with PGM grades of up to 3.9 grams palladium and 0.68 gram platinum.