Philadelphia, Pa. Paper - Notes on the Patio Process

The hacienda Sauceda is one of the largest and finest haciendas in the vicinity of the City of Zacatecas, Mexico, and is said to reduce ores by the Patio process more cheaply than any other establishment. It receives its supply of ore from the San Acacio mine. This mine has been for some time, like most of the Zacatecas mines, out of bonanza, and yields, at present, ore of rather low grade. The silver occurs principally as silver-glance, ruby-silver and native silver, associated with pyrites of iron and copper, and some galena and zinc-blende, in a gangue of pure quartz, which takes the form of amythyst whenever the ore is of high grade. All the ore, as it comes from the mine, is broken by hand into small pieces, and sorted before it is delivered to the hacienda. Here it is first crushed dry in Chili mills, and then ground wet in arrastras to an impalpable powder. The sulphurets not decomposed in the patio process are separated in the settlers from the tailings and concentrated by hand. By roasting them in a reverberatory furnace with carbonate copperores, "magistral" is obtained. All machinery is driven by mulepower.