SAN DIMAS

PROCESSING

Milling operations are carried out at Tayoltita. The Tayoltita mill processes ore from throughout the district and has a current throughput capacity of 2,100 tonnes per day. The mill facility is a conventional operation that employs cyanidation and zinc precipitation for recovery of gold and silver.

The Tayoltita mill has undergone a series of plant expansions over its operating life.

In December 2005, crushing capacity was increased to 2,100 tonnes per day, as well as improvements to the chemical treatment / leaching area.

The Tayoltita mill employs fine crushing and single stage ball milling to achieve a fine grind before passing into the leach circuit. Leaching is completed in a series of tanks providing 72 hours of leach residence time. The pregnant solution is recovered in a CCD circuit with the gold and silver recovered from solution in a zinc precipitation circuit.

Tailing is pumped by a newly installed single stage pumping station to the tailings impoundment area in a box canyon east of the mill site. The gold and silver precipitate is refined using an induction furnace to produce 1,000 ounce gold and silver dore bars.

The Nukay mill uses the cyanide process and Merrill Crowe precipitation.  Run-of-mine ore is fed to a three-stage closed circuit crushing plant. Crushed ore is fed to two ball mills via two storage bins.  Sodium cyanide solution is added to the ball mills. The milled ore is sent to a classifier where the pulp is separated from the pregnant solution.  The pregnant solution is sent to filters and then to the Merrill Crowe precipitation unit.  The precipitate is melted in a crucible to produce doré.