Bulletin . on may produce apparently discrepant results by actingin different order in different tests, and that when properly under-stood and accounted for such results may yet be brought into , if this were not credible, all attempts to determine adequatelengths of protection zones in mines by extrapolation would appearfutile. At the time of writing this report no information could be obtainedat either station as to any existing ratio of increase between varyinglengths of coal dust and stone dust. But as the recording instrumentsat Altofts have shown that the pressure increases
Bulletin . on may produce apparently discrepant results by actingin different order in different tests, and that when properly under-stood and accounted for such results may yet be brought into , if this were not credible, all attempts to determine adequatelengths of protection zones in mines by extrapolation would appearfutile. At the time of writing this report no information could be obtainedat either station as to any existing ratio of increase between varyinglengths of coal dust and stone dust. But as the recording instrumentsat Altofts have shown that the pressure increases but slowly over adistance of 200 to 300 feet, and then suddenly rises to the maximum,it may be assumed that if a coal-dust zone of, say, 600 feet wereemployed for originating and propagating an explosion, the pressuresobtained in an adjacent stone-dust zone would be very differentfrom those obtained by shorter lengths of the propagating the employment of the relatively short propagating zones at. .1. TIME MARKER, ALTOFTS EXPERIMENTAL GALLERY.
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectminesandmineralresou
