Canadian base metals miner Capstone Mining has been granted approval from the US Federal Trade Commission (FTC) to proceed with the $650m acquisition of the Pinto Valley copper mining operation and the associated San Manuel Arizona Railroad Company in Arizona, from BHP.

Capstone entered into an agreement with BHP Copper, a subsidiary of BHP Billiton, to acquire these assets on 28 April 2013.

The Canadian company also announced that the restart of the Pinto Valley Mine is proceeding according to the schedule. As of 27 May 2013, throughput over a 20-day period during May averaged about 49,100 tons per day at an average grade of 0.33% copper, producing approximately 6.5 million pounds of copper.

Copper recovery averaged 84.2%, producing a copper concentrate with an average grade of 29%.

Capstone Mining president and CEO Darren Pylot said, "The successful restart and FTC approval are two important steps towards closing of the Transaction."