OMCO owns the rights to Block 10 with well connected roads and towns in its vicinity. It is located approximately 100 km South of Sohar. Block 10 has significant resources of Cu-Au mineralization found during various exploration activities. Besides Cu-Au the block includes significant chromite potentials. OMCO’s strategy is similar with the copper blocks in dealing with the environmental heritage from before and implementing a green and sustainable operation thereafter.
The project was to find out how to apply a cost effective technology to clean up contaminated ground and surface water, and tailings. In parallel the pilot analyzed how to get metals, especially gold, into solution and to test GGT’s proprietary gold extraction technology, mostly to establish cyanide free leaching and a cost effective, environmentally friendly, large scale leaching process to remediate large amounts of mining waste. The proof of concept has been successfully delivered and in extensive serials of tests and analysis it could be established how to proceed with the next phases of the project.
The Gold plant is located in Rakah, Wilayat of Yanqul. The plant was commissioned and commenced production in August 1994. The annual design capacity was to produce approx. 500 kg of gold. The process plant was a simple conventional cyanide leaching method with the gold recovery by activated carbon. The gold ore produced by OMCO was sent to an overseas refinery for further processing.
Run of ore was crushed in jaw crusher. The concentrator utilized autogenous milling and water flotation. This was a two stage fully autogenous circuit; the primary mill provides pebbles for a secondary mill through a pebble extractor valve in the primary mill discharge trunnion actuated by the power draw of the secondary mill.
Thickener concentrates were dried in a gas fired rotary drier. Tailings are pumped to the tailings pond area where surplus water was evaporated.
The concentrate was pelletized and dried to 1% moisture. The pellets were mixed with limestone, silica flux and recycled copper bearing flue dust and fed into a 7 MVA electric furnace. The furnace smelted the copper concentrate and fluxes produce copper matte and slag. The copper was transferred to one of two Pierce Smith converters where sulphur and iron were oxidized by blowing with air. The blister copper was finally fire refined in an anode furnace, blown successively with air increasing the copper grade and the copper was cast into anode.
The slag produced in the Smelter was sold to a local company. The smelter plant was designed to treat 80 000 tonnes of copper concentrate annually.
In the electrolytic refinery, the anode copper was further refined to produce copper cathodes of 99.999% purity, which was exported to various destinations. The designed annual production capacity was 20 000 tonnes copper cathodes. A study was undertaken to increase the capacity to 24 000 tonnes per annum.
The anode slimes produced in the Refinery was again processed in an overseas refinery for recovery of precious metals (Gold & Silver)
Electric power to Sohar Copper Project and Township was catered by two 18 MW heavy duty industrial gas turbines owned and operated by OMCO. Surplus power over OMCO requirement was currently exported to other entities.