:: Burnakura Plant Optimization Study Underway
ATW Gold Corp. reports that it has received several engineering proposals for optimization studies on the Burnakura gold plant. The selected consultant will be announced this week and the work is expected to commence by the 15th of June 2009. The scope of the study includes a number of plant optimization measures that will allow the plant throughput to increase from the current 18-20 tonnes per hour (tph), to a target of 25-30 tph. This will allow an increase in gold production from the current rate of 35,000 ounces gold per annum to 50,000 ounces annually during the fourth quarter of this year.
The scope of works will be carried out in 2 stages as follows:
The addition of a gravity circuit
Gold mineralization at Burnakura is predominately free of entrapment from other minerals and as such is recoverable through gravity separation. Plant operating efficiencies will improve with the incorporation of a gravity concentrator into the grinding circuit of the plant. ATW owns a Falcon concentrator, which will form the critical component of the gravity circuit being installed.
Refurbishment of the existing regrind ball mill
The Burnakura plant assets include a 1.7 metre (m) x 1.7m 90kW regrind ball mill that has not been commissioned. The intent is to refurbish and commission this secondary grinding mill to treat the gravity tailings stream.
Additional leach capacity
The leaching capacity of the plant is limited as a consequence of tank capacity. ATW proposes to install an additional 8.5m x 5m diameter leach tank and install inter-tank screens to start the adsorption of gold earlier.
The tailings discharge pipeline and pumping capacity are being doubled to accommodate the increased plant throughput.
Commissioning of an atmospheric elution and electrowinning circuit
In anticipation of expected increases in gold production, an atmospheric elution and electrowinning circuit is being installed and commissioned, to generate significant cost savings over the existing third party carbon stripping arrangements. ATW’s first onsite gold pour is expected in mid July.
The existing two stage crushing circuit, in addition to its operational support equipment, will undergo major upgrading in a staged process to improve availability and reliability. The existing crusher screen will be replaced with a unit of at least double the capacity allowing tighter product tolerances and improved output. Provision will be made for inclusion of an additional tertiary crusher and for conversion to three stage crushing, ultimately providing even greater output and finer feed to the grinding circuit.
Conversion to a CIL circuit
The existing leaching circuit at Burnakura consists of 3 CIL tanks and 6 smaller CIP tanks. The conceptual plan for upgrading the plant consists of converting the leaching circuit to an 8 tank CIL circuit. ATW has already acquired additional 8.5m high by 5m diameter leach tanks from the adjacent Reedy’s mine, and these tanks will be incorporated into the leach circuit to increase the plant throughput to 30 tph.
Brent Butler, President and CEO, states “We are extremely encouraged with the performance of our crews and operations at Burnakura since production began three months ago. Based on early results, we are expediting our efforts to significantly increase Burnakura’s gold production."
In order to focus efforts on development, production and continued exploration at both Burnakura and Gullewa, ATW has decided to withdraw from further exploration and to drop its interest in the Gunbarrel Property in Western Australia.