EXPLOSIVE EXPERIMENTS AT MOUNTEDEN.

New Zealand Herald, Volume XVIII, Issue 6065, 26 April 1881, Page 3

EXPLOSIVE EXPERIMENTS AT MOUNTEDEN.

YjaiERDAY afternoon a series of experiments were made at the Mount Eden Gaol quarries, through the kindness of the gaoler, Mr. B. O'Brien, with dynamite manufactured by the Australian Lithofraeteur Company. The experiments were conducted by Mr. R. C. Gault, the travelling agent for the company, who has recently visited the Thames goldfield for the purpose of familiarising the mining community with explosives manufactured by the above company, and of showing their superiority in many respects over those iu use. The first experiment was made at a mass of rock about '20 tons iu weight, and the hole haring been prepared previously for the charge—S feet S inches deep — eight cartridges, weighing about lib., were inserted and tamped home with a wooden rod. Shortly after the fuse was lit, about half of the mass was toru up aud rolled into the gully, the base of rock hanging to the face of the cliff being so rent and shattered that it could be easily crowbarred out. One peculiarity of the explosion was that pieces of the rock seemed to be completely severed ar.d crumbled to pieces between the fingers. The second experiment was of a much more severe character; the tamping hole was four feet in depth, the charge ,l£lb., or ten cartridges, the mass of rock to be operated on being of huge proportions. This shot tore out a mass of rock aud rent the balance in various directions, so as to make its removal hereafter comparatively easy. A third experiment was to use a small charge on the surface of a boulder two tons in weight. To have given the explosive a fair test a hole three or four inches in depth should have been drilled. : As it was, it was simply laid on the surface, and on being fired the boulder was found to be fissured throughout its entire proportions. Another experiment was made on a stone weighing half a cwt., and a single cartridge used, but as the surface of the stone gave no resisting power and the charge was too small, the result was not so satisfactory. The rapid decline of daylight prevented the experiment being repeated with, a stronger charge. For mining purposes and breaking down it seems admirably adapted. As by a special patent which the company has taken out, it is almost entirely free from the noxious fumes which arise after exploding a shot with that previously in use, this effect being produced by subjecting the nitro-glycerine to a series of chemical baths before mixing with the infusorial earth. The dynamite may be handled easily and safely. The lithofraeteur manufactured by the company contains rather less of the explosive chemical than dynamite, but though slower in explosion/ from the thorough combustion of the ingredients, gives more rending, if less explosive power; and is therefore more suitable for soft or open country. The factory was. established half-a-dozen years ago, at Baysbrook, near Melbourne, under the: direct inspection of Herr Engel, son of the . inventor of lithofraeteur. The company make' both dynamite and lithofraeteur, both of which explosives are nitroglycerine compounds, the former containing 75 per cent, of this chemical and 25 per cent, of infusorial. earth,' a kind of fine silica. Nitroglycerine, notwithstanding its dangerous character singly, when absorbed by the earth, is perfectly safe. A charge.of this company's dynamite and lithofraeteur/ 12501b5. weight, in equal proportions, was recently exploded at the Grey mouth harbour works, affecting a mass of 9000 tons of stone. The. Auckland agents for the sale of the Australian Lithofraeteur Company's ex? plosives are Messrs. T. and. S. Morrin, of Queen-street. . . ■