§ Mr. W. Whiteleyasked the Secretary for Mines whether any recent official tests in shot-firing with stemming plugs have been made, and with what result?
§ Mr. LloydSome further trials have recently been carried out, and I have reviewed the matter generally. These and previous trials indicate that as compared with some of the methods of stemming previously used, advantage may in certain circumstances be obtained from the use of stemming plugs. In particular there may be an economic advantage in cases where coal can be got more effectively or in better condition by means of "cushion blasting."
There are, however, other stemming materials and other methods of "cushion blasting" by which similar results can be obtained with equal safety and efficiency. As the conditions in which shots have to be fired vary so widely, there is scope for the use of all these different materials and methods of stemming.