First class toll milling to the local gold mining industry
FMR Investments was formed in 2007 when specialist hard rock underground mining services provider Barminco - founded in 1987, divested its contracting business. Today, the company operates three mining projects in Australia: the Eloise Copper Mine in northwest Queensland, as well as the Greenfields Mill and Gordon Sidar mine, both of which are located in Western Australia.
Stockpile ore delivered by FMR’s customers initially passes through a three-stage crushing circuit consisting of a primary jaw crusher followed by secondary and tertiary cone crushers. The feed from the secondary and tertiary crushers is graded by a double deck screen that removes undersize material from the circuit. The crushing system produces a P80 product size between 6 and 8mm which is then transferred and stored in a 1000 tonne mill feed bin.
The mill circuit consists of 1300, 875 and 500 kW ball mills. Classification of leach feed product is handled by 15-inch cyclones. Free gold particles in the cyclone underflow are separated in a concentrator and sent to the gold room for direct smelting, while the remaining underflow goes back to the grinding circuit to be further reduced.
The overflow product from the cyclones is sent to a CIL (Carbon-in-Leach) circuit. In this process, gold is dissolved from the ore in a cyanide solution in the presence of oxygen, and the resultant gold cyanide complex molecule is then absorbed onto activated carbon. The gold is stripped from the loaded carbon, in a process known as elution. Gold is later recovered from the pregnant strip solution by electrowinning onto steel wool, and direct smelting before shipment to an external refinery.