Great Basin Gold Successfully Completes Refurbishment of Esmeralda Milladmin
Monday, August 10th 2009
Great Basin Gold Ltd announces that it has completed the refurbishment of the Esmeralda Mill. The Esmeralda Mill will process material extracted from the Hollister Gold Project at which trial mining is currently underway.
The commissioning process at Esmeralda commenced in mid July. The commissioning will proceed in two phases. Following the completion of a concrete ore pad, low grade material from Hollister was shipped to Esmeralda. This material will be used for the first-phase cold commissioning of the mill with higher grade material to follow in the second phase. A Gekko float and gravity circuit will be installed and commissioned by the end of October 2009 to allow for maximum throughput of 350 tons per day and an estimated 91% recovery of the high metal content material from Hollister.
Until the Gekko float and gravity section has been commissioned, the rate of milling will be determined by the grade of material. The mill will achieve the designed rate of 350 tons per day on material with a contained grade 0.5 oz/ton Au and 3 oz/ton Ag or less, using a standard concentrator. In the interim, higher grade material will be restricted to allow for extended leach time to get optimal recovery as well as the elution of the higher metal values from the loaded carbon.
Construction of a new refinery at Esmeralda will coincide with a design completion that incorporates the new state-of the-art emission controls consistent with the Nevada Department of Environmental Protection Mercury Control Program. Commissioning of the refinery will commence upon receipt of the air quality Permit to Construct. In the interim, concentrate will be refined off site.
Capital expenditure on the refurbishment has increased as a result of an additional upgrade cost (US$1.8 million) that would allow for the plant to be expanded to a 700 tons per day operation in future as well as the cost (US$1.2 million) of certain additional environmental requirements which affect the final design and construction of the mill and associated infrastructure. The total cost of refurbishment (excluding refurbishment and commissioning of the smelter and additional investment to upsize the mill) is forecast to be US$11 million.
Ferdi Dippenaar, CEO commented; “We are pleased with the manner in which the refurbishment and upgrade of the facility was completed. No problems have thus far been encountered with the commissioning of the facility. The addition of the flotation and gravity section will allow higher throughput and recoveries of the high grade material being extracted at Hollister. Projected milling costs of approximately US$110/ton, transportation included, are significantly lower than the treatment costs currently incurred. Since acquiring the Esmeralda mill and property, the Company has evaluated the option of increasing the capacity of the mill to 700 tons per day. A decision to increase the capacity of the mill will be determined by the conclusions from the desk top study due for completion in August. This study includes a review of the Esmeralda deposit, a past producer, to determine the potential to re-open the mine.”