Dia Bras pours silver bar from leached tailings

Dia Bras Exporation (DIB-V) has poured the first silver dore bar from its new cyanide leaching circuits at the Malpaso mill in Chihuahua state, Mexico.

The company began constructing the leach circuits in August and began leaching the mill tailings in late November.

Dia Bras says having the leach circuits will allow it to increase silver recovery considerably.
This first bar weighs 13.23 kg and contains 42.6% silver (172 oz. silver), 32.4% lead, 6% copper, 1.7% zinc and 17.3% other metals. The gold content is low at 3.5 grams per tonne but that was expected – Cusi mineralization is low in gold.

Dia Bras is able to recover 68.26% of silver through the flotation mill. With the new leach pads, the company can recover another 12.19% of silver from the tailings so the overall recovery is 80.45%.

The company hopes to improve this as the leaching continues. It’s striving for silver recovery between 80-85% based on previous metallurgical testing.

Right now there are two vats in operation but another four vats will be added to the system soon. Construction will begin in early January and all six should be operational by March 2010.

Each vat has a design capacity of 400 tonnes of tailings and has a one-week cycle for leaching. Once the company has six vats constructed, one will be used as a reservoir and the other five will process tailings for a capacity of 8,000 tonnes per month.