Colliery engineering by Unknown

Author:Unknown
Language: eng
Format: epub, pdf
Tags: Coal mines and mining -- Periodicals, Mineral industries -- Periodicals
Publisher: London Tothill Press

nCS tRa MINCRUI.

Fig. 1

substituting the various values, A =

.008727 X (5)2 X 106.2604 - ^(5 - 2)

= 23.18-12 = 11.18 square feet. For all practical purposes the angle C may be taken to the nearest whole degree. Thus, if we use 106° instead of the more exact 106.2604°, the area of the sector (the first term of the fonnula) is 23.13 instead of 23.18, which difference is much less than that probably due to errors of measurement in the lengths of the lines A B and E F, respectively equal to Ch and H.

The area of the lower, or rectangular, portion of the airway is, of course, 6X8 = 48 square feet, so that the area of the entire heading is 11.18+48=59.18 square feet.

In a coal mine at Doncaster, near Sheffield, England, while a shaft was being sunk, immense quantities of water were encountered rendering the pumps useless. Those in charge adopted the freezing process. All around the shaft, down to the depth of 130 meters, auxiliary holes were drilled, throvigh which a freezing mixture was introduced. In this way the ground in the vicinity of the shaft was frozen, as also was the water, thus forming around the original shaft a safeguard which made a continuance of the work possible. After the shaft had been walled up water-tight, hot water was nm through the auxiliary pipes, which were then removed.

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