C.—4.

tubs. Of four Inspectors of Mines giving evidence before the British Royal Commission all recommended that sufficient clearance should exist between the trucks and the sides. A recommendation as to this appears further on. The use of chains on jigs, or self-acting inclines, where usually only one loaded tub during its descent by gravity pulls up the empty tub, was frequently unfavourably referred to in the evidence. The haulage chain passes through a staple on a single prop, and runs on a metal plate, causing so much noise when running that it is a source of danger. The extra jar through the roughness of the running was considered not only a source of accident on the incline itself, but to some extent likely to cause accidents through the jig-props springing, and also by increasing the liability to falls of the roof. On the face-jigs — those lowering from the working-face, being the first stage of the self-acting incline — chains, on account of their suitability for lengthening as the face advances, are required. We therefore recommend— (1.) That the use of chains should be prohibited on all but face-jigs, and that wire ropes be substituted therefor. (2.) That provision be made for anchor chains to be supplied and their use made compulsory on all face-jigs. This simple method of preventing runaway tubs, where such occurrences are not infrequent, is likely to reduce the percentage of accidents under this head. (3.) That all haulage inclines, self-acting inclines, and all jigs except face-jigs, be fitted with bells or adequate signalling-appliances. (4.) That Special Rule 89 under the Coal-mines Act, 1908, be amplified to include the compulsory provision and use of adequate stopblocks on all working-jigs. (5.) That a backstay or trailer should be attached to each ascendingtub or set of tubs on every inclined haulage road where mechanical haulage other than endless rope or chain is used. (6.) That in all mines where cages are used by the men travelling in or out of the mine the engine-driver should always be within hearing of the signals when men are underground, and that this should be provided for in both the Coal-mines Act and the Mining Act. (iii.) Explosions of Gas and Coaldust, and Shot-firing. (1.) In almost all the large coal-mines in this Dominion ventilating fans have been installed, but the further measure of prohibiting the use of furnaces and steam boilers in fiery mines has been considered. Not only has the possibility of firedamp been taken into consideration, but the further contingency of ignition of the coal-seam. We are of opinion that both ventilating and boiler furnaces should be prohibited in fiery mines. (2.) The question of the position of the ventilating-appliances has been fully discussed under the head of " Ventilation." It is therefore unnecessary to deal with the matter here further than to emphasize the fact that, as a precautionary measure in case of accident, it is essential that they should be outside the mine, with a proviso for auxiliary fans underground where required. (3.) Coaldust explosions have formed the subject of much inquiry and research by the British Royal Commission on Mines, 1909, and the following extract from their report (pages 85, 86, 97) shows succinctly some of the reasons, in addition to the evidence tendered to us, for the recommendations which follow :— For the starting of coaldust explosions two conditions are necessary : (1) A disturbance sufficient to suspend a cloud of fine dust in the air, and (2) the projection of a flame into this cloud of dust. . . . The means for preventing coaldust explosions may be roughly classified into those which prevent the initiation of an explosion and those which prevent its extension. Again, they say,— It is quite clear that the entire removal of coaldust from a mine so as to render it completely immune against an explosion is out of the question.

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