Bulletin of the American Institute of Mining Engineers Volume 133-136 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1917 Excerpt: ...any of the district. The ore is pyrrhotite, plentifully intermixed with crystals of pyrite and some chalcopyrite. The sulphur content is between 25 and 30 per cent, and the copper is less than 2 per cent. The orebody is nearly 3000 ft. long and varies from a few feet to a maximum of 150 ft. in thickness, the latter being across a longitudinal fold. The workings extend to a depth of over 1000 ft. There are probably tens of millions of tons of ore in the deposit. South of the southwest extremity of the Burra Burra mine is a small deposit known as the Culchote. No sulphide has been mined, but the deposit has been proved by diamond-drilling to be similar to the Burra Burra. Somewhat more than a mile to the southeast of the Burra Burra mine is the Isabella-Eureka orebody. This is in the form of a large anticline, with a fault longitudinally along the crest. The Isabella part is thrown to the northeast and dips to the southeast; the Eureka part is thrown to the southwest and dips to the northwest. The ore is mostly pyrrhotite, well intermixed with pyrite and but little chalcopyrite, a small amount of quartz and lime silicates being present. The sulphur content is approximately 30 per cent, and the copper less than 1 per cent. Very little development work has been done, although there are two shaft to depths of 200 ft. and the deposit has been diamond-drilled to a depth of 500 ft. As the ore has been found to be wide near the surface, as well as where crosscut by diamond-drilling, there are probably more than ten million tons and perhaps many times that amount of ore in the deposit. About 2 miles to the southwest of the Isabella-Eureka deposit is the Mary-Polk County deposit, which shows more faulting and folding than any of the other deposits of the district. To ...