Show SILVER ORES IN THE SAN JUAN REGION one of the most interesting mining regions in the united states scenically historically and geologically is that including the san juan mountains in southwestern colorado which contains silverton telluride ouray rico and other mining towns in these mountains are camp bird smuggler union liberty bell tomboy yankee girl sunnyside Sunny side silver lake Enter enterprise prie and other well known gold and silver mines some of which have yielded also much lead it many of the ores of the san juan mountains contain minerals that are rich in silver and the question has often been asked were these minerals formed by water that percolating downward collected the silver silve r from the upper part of the vein and it at a lower level 0 or were they formed by the hot ascending waters from which the ores were originally deposited if formed by the first process the rich silver ores would represent the downward enrichment of a comparatively low grade vein and would be confined to its upper part if formed by the second process the rich silver minerals might continue to as great a depth as any other of the ore minerals it was therefore important to determine if possible the process by which the rich silver bearing minerals were formed this problem was studied by E S bastin of the united states geological survey whose report has recently appeared as bulletin D silver enrichment in the san juan mountains colorado mr bastin finds by and chemical study of the ores that though some of them were formed by downward enrichment others were deposited originally in i the vein and may therefore occur at depths far below the bottom limit of enrichment this discovery is decidedly encouraging to the future operation of some of the mines the report is illustrated by many diagrams s showing the relations of the several silver bearing minerals as seen under the microscope in thin sections of the ores |