Engineering and Contracting . andling of cars. A convenience for saving time was theuse of a flanged valve on the headingend of the pipe line, instead of the screwvalve commonly employed. There wasalso a telephone system, one station ofwhich was kept well up toward the head-ing. In case of accident, or when it wasnecessary to communicate with the portalor power house, the use of the telephonesaved valuable time. Vcnti!atio)t.—The removal of powder makes a comparison of this work withthat done in the Cinderella mine, in Trans-vaal, account of which appeared in En-gineering-Contracting Nov. 20,
Engineering and Contracting . andling of cars. A convenience for saving time was theuse of a flanged valve on the headingend of the pipe line, instead of the screwvalve commonly employed. There wasalso a telephone system, one station ofwhich was kept well up toward the head-ing. In case of accident, or when it wasnecessary to communicate with the portalor power house, the use of the telephonesaved valuable time. Vcnti!atio)t.—The removal of powder makes a comparison of this work withthat done in the Cinderella mine, in Trans-vaal, account of which appeared in En-gineering-Contracting Nov. 20, 1907, page^91. Mr. Dinsmoor has the following tosay: Taking the figures from these two ar-ticles we have the following comparativetable: Rand. Cripple Ck. Size of bore 5x7 ft. 9x9 ft. Rate of progress per mo. 225 ft. J7S ft. Number of machines usedper shift 3 2 Number of men em-ployed per shift 8 6 Number of holes drilledper round 15 20 Length of shift, hours. 8 8 Max. distance over which spoil had to be trammed 800 Fig. 3—Showing Tunnel Work in Progress. smoke after shooting was accomplished bymeans of a blower and the compressed airsystem. As soon as the work of drillingstopped, the engineer would notice the factthat the demand for compressed air hadceased; he would then fill the receiversand pipe lines with air at 100 lbs. the holes were loaded and fuses spit,the drillmen would open the gate valve atthe heading, allowing a full stream of airunder 100 lbs. pressure to play on the facethrough a i-in. whistle cock. This volumeof air, coming with a high velocity, stirredup the smoke and mixed thoroughly with pressure in the pipe lines droppedrapidly, and as soon as the pressurereached 20 lbs. the engineer started thecompressor and kept the pressure at thispoint, and also started the blower, if itwas not already running. A is-in. ventil-ating pipe was used and the smoke wassoon thoroughly mixed with fresh air. Itwas seldom that men could not get t
Size: 2045px × 1222px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookpublisherchicago, bookyear19
