Placer Mining (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. 1908 Excerpt: ...necessary to experiment before the mine authorities can determine which explosive will give the best results for their mines. Ordinary gases given off from the explosives are carbon dioxide, nitrogen, carbon monoxide, and hydrogen; some of the high explosives give other compounds. Nitrogen is the inert gas in the atmosphere, and neither it nor the carbon dioxide is poisonous, though neither will support life. Carbon monoxide is a highly poisonous gas and the hydrogen is, if anything, slightly poisonous. Explosives that produce nothing but carbon dioxide and nitrogen are the least objectionable, and those that produce the maximum amount of carbon monoxide are the most objectionable. Some explosives also produce various sulphur gases or fumes, and dynamites send into the air about 25 per cent, of their weight of solid matter. 75. Decay of Timbers.--Another cause for the pollution of mine air to be considered is the decay of timbers This is not only a deoxidizing effect, with the evolution of carbon dioxide, but the timber may putrefy, resulting in the emanation of various noxious gases. When timbers left in an old mine decay, they have been known to produce explosive gases, which, when the workings have been broken into, have rushed in on the miners, sometimes producing disastrous explosions. In many instances, the removal of decaying timber cannot be accomplished; but so long as there is an offensive smell arising from such sources, an additional supply of air is needed to prevent injury to the health of the men. 76. Dust.--Metal mines are more likely to be very wet than too dry, but there are some that are very dry. The dust resulting from the handling of ore, from drilling, and from blasting in a dry mine is liable to be very sharp and injurious to the lun...