OVERVIEW

The Lefa gold plant was an existing plant in Borneo, Indonesia called Kelian. The plant was disassembled and shipped to site, constructed and is being commissioned. The plant is sized to process is 7.2 MTPA of combined Oxide and Primary ore.

The project consists of 2 separate crushing locations. Each consists of a ROM bin, a rock breaker (Lero Karta only), apron feeder and jaw crusher. The Lero Karta crushing station is located at the Lero Karta pit, and crushed ore will be delivered to the plant site by a 6 km x 900mm wide overland conveyor.

The Fayalala crushing station is located at the plant site. The Fayalala site further consists of a Stockpile, 2 conveyors feeding 2 SAG mills (each 1750kw, 8.41m diameter x 3.23m long), 2 Ball mills (each 3500kW, 5.49m diameter x 7.32m long), 2 Cyclone clusters, and 2 Trash screens makes up the milling circuit. Gravity gold gets recovered in 5 Knelson concentrators and an Intense leach reactor.

Milled cyclone overflow is thickened in two 28m diameter thickeners in parallel, and from there the circuit passes through 6 Leach tanks and 6 Adsorption tanks with a combined volume of 43,660m_, then on through elution, electrowinning and finally to gold production. Raw water pipeline is 400mm diameter x 2km, tailings 500mm diameter x 5.5km, return water 250mm diameter x 2km, process water 450mm diameter x 0.5km. There is ± 18 kilometers of overhead power lines at various HT voltages. The PowerStation is HFO and diesel powered producing 36MW of power. A 6km long overland belt conveyor system has been installed as part of the Lefa Corridor Gold Project. The conveyor links the satellite crushing station at Lero Karta, to the main CIP plant at Fayalala. The conveyor has been designed to handle 825 tonnes/ hour of crushed ore on a 900mm wide conveyor.

The severly undulating topography of the conveyor’s route has been accommodated by the design and installation of free standing idler support steelwork. The topography further demanded an in-depth dynamic analysis, to ensure that all starting and stopping scenario’s were catered for. The analysis also ensures the selection of “fit-for-purpose” cost effective equipment