EXPLORATION 1998 — Reserve boost at Skorpion deposit

London-listed Reunion Mining has reported a 50% increase in tonnage and a 10% increase in the average grade of the Skorpion zinc oxide deposit near Oranjemund, in southwestern Namibia.

The company is earning a 60% interest in the deposit from a subsidiary of Anglo American of South Africa. During the past nine months, Reunion has completed 84 diamond drillholes totalling 5,618 metres, and 113 reverse-circulation drillholes totalling 11,150 metres.

These holes have tested the deposit on a 50-by-50-metre grid; in some areas, in-fill holes also have been drilled. The deposit is 750 metres in length, up to 250 metres wide and roughly 30-60 metres in thickness. Mineralization extends to 180 metres below surface at its deepest point.

Probable reserves (verified by an independent consultant) now stand at about 15 million tonnes grading 11.3% zinc. Total resources and reserves stand at 21 million tonnes at a grade of 8.4% zinc. The overall stripping ratio is 2.5-to-1.

The project is amenable to processing by direct leaching, such that zinc metal would be produced on site. Cash operating costs are projected to be less than US23cents per lb. of zinc metal.

The recent reserve boost has prompted Reunion to examine the possibility of increasing production to between 130,000 and 150,000 tonnes per day over a mine life of 10-12 years.

Reunion has collected a representative bulk sample from drillholes spread throughout the deposit; it will be used to feed a pilot-plant designed to confirm the viability of the flowsheet. It also will provide engineering and operating cost information.

Reunion notes that the increase in reserves has resulted in a slight delay in the scheduled completion of the feasibility study, which is now expected in the final quarter of this year. The delay will allow more drilling to upgrade the new reserves to the proven category.

Tecnicas Reunidas of Spain, a leader in zinc solvent extraction, will be providing preliminary engineering designs for the leaching, purification and solvent extraction stages of the flowsheet. Basic engineering for the balance of the flowsheet (electrowinning, melting and casting) will be provided by Union Mini’re of Belgium. Engineering design and costing will be carried out by Bateman Mineral and Industrial of South Africa.