Sunstone Metals (ASX:STM) said a metallurgical test work program on the Brama-Alba-Melonal porphyry deposits at its Bramaderos project in southern Ecuador has returned revised average recoveries of 80% for copper and 93% for gold, above the scoping study assumptions of 75% and 85%, respectively, according to a Tuesday Australian bourse filing.
The company said locked-cycle flotation testing achieved copper recoveries of up to 83% into concentrates grading about 18% copper, the filing added.
The company's shares closed 4% up on Tuesday.