Show HUMIDITY OF MINE AIR an investigation of the humidity of mine air with especial reference to the coal mines in illinois has just been completed under a operative cooperative co agreement between the united states bureau of mines the department part ment of mining alining engineering of the university of illinois and the illinois geological survey the results of this investigation are contained in bulletin 83 of the bureau of mines written by ar R Y williams the bureau of mines paid particular attention to those phases of the investigation that were of general interest from their bearing on safety and efficiency in the coal mining industry as a whole thus it studied the occurrence of gas in the southern part of tile the state tested the inflame ability of coal dust of many mines examined the efficiency of the control of vent ventilating nat currents and investigated the factors affecting the humidity of mine air with reference to their bearing on mine explosions plo experiments in ill the gas and dust gallery at the pittsburgh testing station of the bureau of mines verified the fact that certain dusts that explode violently when dry are rendered inert by proper humidification of the atmosphere within the gallery and the importance of humidity as a factor in limiting the inflammability of coal dust in a mine is demonstrated by the fact that there has never been in illinois a dust explosion during the summer months whereas the records show a number of dust explosions plo during cold weather it is easy to see that the warm moisture laden air that enters a mine in the summer must deposit moisture on cooling whereas the cold and relatively dry air that enters in winter must take up moisture as it becomes heated in traveling through the mine A study of humidity in the coal mines of the state was begun in january 1912 by the illinois coal mining investigations previously mentioned in operation cooperation co with the united states weather bureau and the operators of twenty typical mines in the state in this study records were made that show the changes both underground der ground and on the surface during the seasonal changes of a complete year these records afford a basis for generalizations as to humidity the records with pertinent discussion are presented in this r re port for the purpose of supplying information that will assist operators and miners in making mines safe from coal dust explosions plo the following general conclusions are reached by the author the fact that dry bituminous coal dust will explode under certain conditions has been proved both by the experience of the past and by laboratory tests and is now generally admitted by coal men the coal dust may be rendered inert by the proper application of moisture has been shown both by laboratory tests and by the absence of explosions at mines in which moisture is present in the proper proportion to the quantity of dust produced the result of the investigation in illinois of the humidity of mine air leads to the belief that steam may be supplied to the intake air in such a way as to offer the most economical and efficient effi cent method of dampening coal dust 0 |