SFMI GEO REports

More relevant quotes from "Geology and Metalliferous Resources of the Region Around Silver City, Idaho", by A. Piper and F. Laney, 1926, Bulletin no. 11, 162 pgs.

Pg. 72

... Such records of (ore shoot) past productions, and such additional information as appears to be reliable indicate that, exclusive of the enriched bonanzas (near the surface), the ore shoots were of consistently good rather than fabulously high grade. The value of the ore as mined ranging from $15.00 to perhaps $50.00 and averaging about $25.00 per ton (today's value would range from $700.00 to $2,400.00 per ton and averaging $1,200.00 per ton. These figures are for ore shoots only, and do NOT represent normal ore values in the mines- Ed)

Pg. 89

The question of whether or not the ores are deep and consequently persistent, or shallow and readily exhausted, or possibly already worked out, is of course the most vital economic point in the geology of the region (Silver City mines). The veins are true fissure veins, developed in fissures produced by profound diastrophic forces ( movement of the earth's crust, resulting in ocean basins, continents, plateaus, and mountain ranges- Ed), and are certain to extend to depths far below the possibility of mining. The vein fillings, both gangue (valueless rock - Ed) and primary ore minerals, are those derived from deep-seated sources. They are in no way genetically related to the rocks in which they are found, and their composition is such as to all but prove a deep seated source. We conclude, therefore, that the veins will probably extend to unknown but great depths.

Pg. 91

Careful examination of such material (historical geological and economic geography reports, and newspaper articles) as was available shows clearly that much of the best ore produced in all the important mines is in no way affected by secondary enrichment, and consequently the ore as originally deposited carried workable amounts of gold and silver probably not much below the averages shown by returns from the last several years of operations.

Pg. 92

By way of summary, it may be stated that the field and laboratory studies of the Silver City ores have shown: (1) that the exceedingly rich bonanza ores in the upper portions of the ore shoots were formed by the surfical enrichment of already rich primary bodies, and, (2) that the primary ores range from good to high-grade ores and that they may be expected to continue as good ores to depths much greater than any thus far reached in the district (Silver City mines).