KREBS’ LITHOFRACTEUR.

New Zealand Times, Volume XXXII, Issue 4999, 2 April 1877, Page 2

KREBS’ LITHOFRACTEUR.

Some interesting experiments with the above compound, which is manufactured by Krebs’ Bros, and Company, patentees, of Cologne, were made bn Saturday afternoon up the Kaiwarra Creek.' ' The agent for. the company is now in Wellington, being on a tour through the colonies for the purpose of making the patent more generally known by bringing !it prominently before the public in the way of exhibiting its power for blasting purposes. It should be unnecessary to make allusion to the importance in a country like New Zealand of obtaining an explosive agent which will safely, efficiently, and economically carry on mining operations, and it is well known that the disadvantages,* of the ordinary blasting agents are numerous. , The compound of which we write has an immense advantage over other agents, and the experiments with it have, it is said, surpassed everything yet accomplished. - The trial ' on Saturday was made under certain disadvantages, and yet the result proved very satisfactory to those who witnessed it, a number of gentlemen having proceeded to Kaiwarra for the purpose. In the first place the agent had found difficulty in getting assistance, and then a .bad choice of country was made for the test, the stone being too soft. However, as before stated, the result was satisfactory. The first hole was bored 2ft. 6in., the charge consisting of 8 ounces of lithotracteur, but the effect of the explosion was not so great as expected, owing to the fact that the hole was bored in a fissure, instead of ’in the solid rock. The ae-“ cond was more successful. Five ounces of the compound were put in a hole on the. hill at bend ,of the creek, and the explosion literally shattered the whole side of the hill, so that large pieces of the stone could he displaced, without any trouble, almost by. the aid of a walking-stick. But it was perfectly evident that the real power of the patent was' not to be seen in.“soft country,” as miners say, this being shown by an experiment made on a large boulder in the bed of the creek. In a hole six inches deep two ounces of the compound were lodged, and the effect of the explosion was to rend it asunder completely. Then a charge was placed in the trunk of a tree, which it opened up for a distance of four feet.. The most interesting of the tests, however, were those made by placing the lithofracteur under water. One charge being placed under an immense trunk of an old tree which lay in the water, it threw up the timber, and cast up an immense volume of water in the shape of spray some fifty or a hundred feet high. One remarkable feature about the com-

pound is that the effect of its explosion seems to have a downward tendency, as was shown by one of the experiments made. A charge being placed on a piece of stone, and covered only by a little earth to keep it in position, the stone was torn to pieces by the shock. Lithofracteur has among other advantages one which will commend itself strongly, the little danger attached to its use—ordinary care being exercised—as compared with other explosive agents. For instance, the compound itself will not explode by contact'with Same, but only by extreme heat. The explosion is caused by the communication of the {me sith the caps, which are separate, and placed in the compound as required. One very imnortant feature iu the lithofracteur is, we understand, that noxious fumes do not result from its proper use, even in badly ventilated mines. The following directions for use are given in a pamphlet published by the manufacturers:— The charging of the holes is effected by dropping the cartridges singly into the borehole either whole or cut into halves—the latter method being preferable—and ramming down each cartridge or piece singly and tightly with a wooden rammer, and with a pushing action rather than a blow, so as to fill the entire circumference cf the hole. This operation is to be repeated until a sufficient quantity of the explosive has been put in, which generally is when one-fourth the depth of the bore-hole has been filled. On this charge another opened cartridge or primer, into which a proper detonator w<th sufficient length of fuse has been inserted, is gently pushed down, and the hole tamped with clay, turf, sand, or water. Water tamping is always preferable, because in the case of a raissfire through a faulty fuse the primer can be withdrawn and another pushed down through the water. The whole of the detonator must be inserted up to its top edge in the priming cartridge, but not deeper, as in that case the top part of the cartri Ige might be set on fire by the burning fuse, and would burn away without exploding. The fuse mustbe gently pushed into the detonator as far as the fulminate, and afterwards tightened round the fuse with a pair of .nippers applied gently to the mouth end of the detonator so as to indent it. On the insertion of the detonator into the priming cartridge, as just explained, the paper of the cartridge is to be bound tightly with twine round the fuse to prevent the detonator slipping out of its place. There is no need to have the fuselonger than is necessary for the safety of the miners, which should be sufficient to enable them to get well under cover. A foot of good fuse burns out in about forty seconds, so that if nine inches or a foot be left hanging out of the blast hole it will be sufficient for all ordinary purposes. It should be observed that the forcing down the charge tightly prevents a vacuum, and is all important for the proper development of tho explosive power of the lithofracteur. Water therefore, as already observed, is recommended to be used in all cases for tamping when possible, as it forms a solid tamping to the closely packed lithofracteur.