The 1989 feasibility study of the chessy, france, copper, zinc, pyrite and barite orebody was based upon a classical flowsheet. The flowsheet included, three stages of crushing, conventional rod and ball mill grinding in series, and sequential flotation of four products utilising conventional mechanical flotation cells. To improve the profitability of the project the partners commenced a search for ways to reduce the projected capital and operating costs of the proposed development. This paper presents the improvements in the projected capital and operating costs as a result of design and concept changes. The major changes included:_x000D_
the simplification of the crushing section with the adoption of semi autogenous grinding (SAG) milling of primary crushed ore._x000D_
the deferral of pyrite and barite flotation circuits until market conditions were positive._x000D_
the simplification of the flotation circuit by the use of column flotation cells for combined rougher/cleaner duty._x000D_
the purchase of second hand equipment. The result of these changes was to reduce the capital cost estimate of the plant from US$ 21 million to US$ 11 million and operating cost estimates from US$ 18.90 to US$ 13.60 per tonne of ore for a decrease of approximately ten per cent in potential revenues.