| OCR Text |
Show 181 Vermicullte Powderhorn Area, Gunnison County, Colorado Occurrence, and History Vermiculite, a hydromica, occurs in the general area of the subject lands In the vicinity of Iron Hill near the Powderhorn post-office in Gunnison County, where the important occurrences are situated in Township 46 North, Ranges 1, li and 2 West, New Mexico Principal Meridian and Township 47 North, Range 2 West, New Mexico Principal Meridian. The date of the discovery of these deposits is not known, but active exploration was in progress as early as 1935. Mining was spasmodic after the discovery of these deposits, but activities were at an increased rate for the period beginning a few years before the outbreak of the second World War. Interest in the area was keen at the June 28, 1938 date set for the appraisal of the subject lands. No records of production are available, but a study of the mine workings indicates that substantial production of the vermicullte-bearing rock has been made. The vermiculite-bearing rock has been mined by open-pit methods and the vermiculite recovered in a concentrated form in local milling plants utilizing gravity and air-washing methods of concentration after crushing- of the rock. The vermiculite recovered has been used as thermal insulating material, as a constituent of light-weight concrete aggregate', and as a soil conditioner. |
