Milling Methods - - - Santa Maria De La Paz - Introduction

The Negociacion Minera Santa Maria De La Paz mining operations are located at La Paz (some eight miles West of Matehuala), State of San Luis Potosi, Mexico. These operations consist of a single copper-silver property, called the Dolores mine and a number of silver-low base metal properties. The ores from these several mines are transported by rail, or truck, to the central milling unit. The milling unit has two separate sections to treat the two types of ore. The ores from the several silver-base metal mines are mixed at the mill as they arrive. Up to the present time the silver-base metal ores have been milled to produce a bulk concentrate which carries valued in gold, silver, copper, lead, zinc, cadmium and considerable arsenic. In such concentration the zinc and cadmium values are lost to the operations in their liquidations as they are shipped as lead concentrates. Since these ores have exceptional quantities of arsenic which is concentrated in the milling process, these bulk concentrates have to be sent to a smelter for pre-smelting operations to remove the arsenic.