How will Fox Resume base metal production?

Fox Resources has been developing an in-house bacterial heap leaching process using bacteria indigenous to the Radio Hill ore since mid 2009.  Current resources show that a nine-year heap leaching operation will take place.  Successful exploration targeting disseminated sulphides that is scheduled to take place during 2011 and 2012 could significantly grow the life of the operation.

What will Fox be processing?

The first year of operation will involve processing the ~275,000 tonnes of ore on surface that has been stockpiled over the life of the Radio Hill mining operation.  Subsequent years will treat the remnant ore in the fully developed Radio Hill mine and ore from the Sholl deposits, this latter ore will be mined from an open pit.  Test work has been undertaken both at site and at external metallurgical laboratories on a number of ore blends and has shown that nickel recoveries of approximately 80% and copper recoveries of approximately 55% can be achieved from heap leaching the ores over a one year period.

How do the bacteria release the metals?

Bacterial oxidation is naturally occurring process that takes place on any sulphide mineral exposed to both air and water.  Cultures responsible for oxidation of the sulphide mineral use reduced sulphur species as a feed source, they gain the energy required for the growth and function by breaking the sulphide bond.  In breaking the sulphide bond the associated metals are released from the ore matrix.  In the case of base metals, such as copper, nickel, cobalt and zinc; the acidic solution associated with bacterial oxidation leaches the released metals into solution.

What is Bacterial heap leaching?

Bacterial heap leaching involves crushing the ore to liberate the sulphide mineral, stacking this onto an impermeable engineered pad, installing an aeration system into the heap and irrigating the heap with an acidic leach solution.  The metals released from the sulphide matrix report to the solution percolating through the heap and are collected in a pond.  Once metal levels in the pond reach the desired levels the solutions are pumped to downstream processing where iron is removed via a two-stage iron precipitation circuit followed by copper ion exchange and precipitation and nickel/cobalt ion exchange and precipitation.  Copper carbonate and nickel/cobalt carbonate will be the precipitate products that will be formed from the process.

Radio Hill Processing Route