Berkeley Mineral Resources (BMR), which extracts metals from tailings at former mines, said that losses widened in the first half, causing its share price to sink sharply on Friday.The company said it "made further progress towards its strategic goal of becoming a processor and supplier of key base metals" in the first half, but is yet to generate any revenues. Losses before taxes at constant currency were £0.9m in the six months to December 31st, down from £0.6m the year before, after spending increased due to the ramping up of production facilities. BMR previously centred its operations at the Kabwe zinc and lead mine in Zambia, which was found to have high grades of minerals in tailings after mining ended in 1994. However, the company has now entered into the much larger copper industry in the country.During the period, the firm secured sources of material, advancing beneficiation studies and processing plans in readiness to start production. The company is now waiting on permission from the Zambian Environmental Management Agency (ZEMA) before starting lead and zinc processing and copper production.ZEMA has set a public meeting for April 11th.The stock was down nearly 15% at 1.26p by 13:22 and has now fallen over 45% since the start of 2014.BC