THE SPANISH MINERS.
The Spaniards had a keen eye for valuable things, and no sooner did they find what the country contained in mineral wealth, than they proceeded at once to develop it.
They opened mines wherever there were indications of silver, and so fast did they progress that it was estimated, at the beginning of this century, that operations were going on in from four thousand to five thousand localities, which might all be included in about three thousand distinct mines. These were scattered along the range of the Cordilleras in eight groups, the principal of which, known as the central group, contains the famous mining districts of Guanajuato, Catoree, Zacatecas, and Sombrerete, and furnished more than half of all the silver produced in Mexico.
The great vein, or Veta Madre, is referred to elsewhere, and is one of the most remarkable deposits anywhere known. It is contained chiefly in clay slate, and crosses the southern slope of the hills in a northwest and southeast direction, dipping with the slates (the range which it follows) from forty-five to forty eight degrees toward the southwest. The width averages a hundred and fifty feet, and the depth is unknown. It has been traced about twelve miles, but its most productive portion thus far, or rather, the portion operated, is only about a tenth of that distance.
The mines of Zacatecas, opened in 1548, are also upon a single vein, called the Veta Grande, averaging in thickness about thirty feet. The formation is of green stone and clay slate, the former the most productive. The veins of Catoree are in limestone, supposed to be of carboniferous age.
THE ORE IN THE MINES.
The greatest proportion of silver in every mining district of Mexico is obtained from the sulphuret of silver, an ore of gray color, disseminated through the quartz matrix in minute particles, and more or less combined with other metals. The other varieties of argentiferous ores are numerous, but comparatively small in quantity; they are the chloride of silver, ruby silver, native silver, argentiferous pyrites, and argentiferous galena.
The comparative quantities of these, at the different mines, is very variable, and few of the miners are able to determine them with exactness. Notwithstanding the antiquity of the silver mining business in Mexico, the processes which are employed are still far from perfect, and greatly behind those of the Nevada and other mines. The ore in Mexico is so rich that it has not been considered worth while to practice any economy or to bring science to the miner’s aid.
Col. Albert S. Evans, who made a journey through Mexico, a few years ago, gives a graphic account of a visit to the Serrano mine, in the vicinity of Guanajuato. He was invited, with several others, to a pyrotechnic display in the mine, and thus describes it: