Abstract :
A new-type electrically driven mining machine is being now tried out in various coal regions of the country. It is a powerful machine that cuts its way into the face of a bed of coal, breaks the coal loose and loads it into mine cars without the exercise of manual labor or the firing of a single ounce of powder or dynamite, such as often cause mine explosions. In a test run, this machine was able to bore its way into a coal seam at the rate of one foot in ten minutes and at a total mining cost of half that prevailing in the handworking sections of the same mine. The entry driven in coal by the machine is 6 ft. high and 11 ft. 6 in. wide. Soc. of Elee. Dev. May 30th, 1926.