Bass Starting Hellyer Development
The Hellyer property was the site of previous mining from 1989 through June 2000. A 1.5-million-mt/y concentrator remains on site, and metallurgical testing has established that the Fossey ore is amenable to sequential flotation in this plant to produce separate zinc, lead, and copper-precious metal concentrates, with no bulk concentrates produced. The Fossey ore is expected yield a total of 105,000 mt of zinc concentrate grading 53% zinc and 150 g/mt silver; 53,000 mt of lead concentrate grading 59% lead, 478 g/mt silver, and 2.3 g/mt gold; and 9,000 mt of copper-silver concentrate grading 18% copper, 4,374 g/mt silver, and 9.1 g/mt gold. The project is expected to generate an operating surplus of A$50 million after capital investment of A$26 million. Production costs are forecast at $0.39/lb of payable zinc after credits for the other metals.
The Fossey deposit will be accessed via a 910-m-long decline and will be mined by underground methods. To increase revenue and to benefit from economies of scale, Bass is also evaluating the restart of its Hellyer tails retreatment project, as well as several toll treatment options, which have the potential to fully utilize the 1.5-million mt/y capacity of the concentrator.