Straits Resources has announced a temporary suspension of processing activities at Hillgrove mine in Armidale, NSW.
The company commenced construction of the Hillgrove antimony/gold mine as a Demonstration Plant in 2007.
The Demonstration Plant was an innovative process designed to produce antimony metals (and gold as a by-product) on site on a commercial basis.
While the plant has produced a saleable antimony metals to LME specifications for the past 12 months, the quantities produced have been significantly below design levels due to a number of issues in the processing plant, according to a company statement.
According to the company, while some rectifications to the plant have been made, issues still remain with effective waste water treatment, the floatation configuration and the interface between leaching and electrowinning.
The company anticipates that processing activities will initially be suspended for up to six months to fully investigate the technical issues, the costs and the time required to implement the required plant modifications to achieve commercially viable production levels.
During the suspension a core group of employees will be retained to continue metallurgical investigations, underground development and exploration.
During the period that processing activities are suspended the cash operating costs for Hillgrove Mine will reduce from $3.6 million to less than $700,000 per month.