The Carosue Dam Operations (CDO) processing plant, modern accommodation village and other vital infrastructure are all located within the South Laverton gold field, situated 120km North East of Kalgoorlie in Western Australia.
The CDO processing plant was constructed by JR Engineering in 2000 and commissioned in November of that year. The CDO operated continuously through to June 2005 when it was put on a care and maintenance program, due to a depressed gold price and at that time a known lack of gold resources.
In February 2006 Saracen acquired the CDO processing plant as part of a package of tenements known as South Laverton from St Barbara Limited. The processing facility and associated infrastructure remained in an excellent condition ready for a potential restart if required. In late 2009 a minimal refurbishment was required to reinstate the mill facility to its full nameplate capacity of 2.4Mtpa.
Historically, the CDO processing plant was designed to treat 2.0Mtpa of primary ore. This could be increased to 2.4Mtpa by blending softer oxide and transitional ore types into the mill feed. The process flow is simple, incorporating a two stage crush for a final product size of P80 12mm and single stage grind to a P80 of 200µm. Gold recovery occurs via gravity concentration and carbon-in-leach cyanidation (CIL). The CIL circuit comprises of seven tanks with an additional two additional tanks to be constructed in 2019 / 2020.
A thickener and paste plant were constructed in 2019 as part of the continued growth of the operation. CIL tails are sent to a thickener and then onto the paste plant which is then utilised as a back-fill product in the Karari mine thereby maximising the gold extraction from reserves.
The plant has processed over 10Mt of ore in its previous five year operating life – averaging 2.2Mtpa, and over 700koz of recoverable gold was produced.
At the beginning of 2010 processing at the CDO plant re-commenced, with gold production being sustained at a rate of 120koz pa from within the South Laverton region of Western Australia. In FY19 the processing plant produced a record 200koz of produced gold as higher grades were processed from predominantly underground ore sources.
Historical performance reflects a well-designed plant, suited to the range of ore types included in the current project reserves. Comparison of actual versus design performance indicated a progressive optimisation of operating conditions over the mine life. No deficiencies or concerns with the design or historical performance in respect of the current project ore sources have been identified, and current performance has the plant operating at a throughput of 2.5Mtpa, which is in excess of the nameplate capacity.
GR Engineering were engaged in 2019 to commence an expansion of the current processing circuit from 2.4mtpa to 3.2mtpa. Completion of this expansion is expected in Q2 FY21.
The on-site facilities also include an administration office, electrical and maintenance workshops, light vehicle workshop, stores warehouse, first aid rooms and emergency response facilities, all of which are fully operational.
Approximately 3km to the South of the CDO processing plant is a modern and well-appointed accommodation village. The village was constructed in 2000 and expanded over the years as required and now consists of 445 bedrooms, wet and dry messing facilities, gymnasium, internet café, EFTPOS facilities, Wi-Fi connections, Foxtel, tennis court, laundries, dining room and recreation room.
A fully sealed all-weather airstrip was also constructed in 2018 / 2019 that can handle 100-seater jets with personnel flown directly to site from Perth.