USE OF EXPLOSIVES

Dominion, Volume 28, Issue 247, 16 July 1935, Page 11

USE OF EXPLOSIVES

Simple Precautions For Avoiding Danger

ACCIDENTS INEXCUSABLE

"Holding cartridges over a fire on a shovel or a frying pan, or placing on the top of a domestic range or in an oven should never be used as means of thawing,” an expert on explosives stated yesterday to "The Dominion” when lie commented on the recent wrecking of a home and the injuring of seven of its occupants when plugs of gelignite were placed in an oven for softening. There were inexpensive and reliable means of thawing explosives, such as by tlie use of warming pans, he said, and there was really no excuse for accidents, for full instructions on the storage and handling were given by dealers and by the Public Works Department. Explosives containing nitroglycerine, particularly gelatinous or plastic types.are liable to become frozen or chilled at temperatures considerably above the freezing point of water. Experts hold that the only safe way of ensuring the best results and freedom from accident in cold weather is to treat all explosives as if they were frozen. This necessitates softening. The only officially recognised way of thawing is in warming pans which are on sale in all parts of New Zealand. The warming pan consists of a jacketed vessel covered with a non-conducting material with an inner compartment in which the explosive is placed. The heat is secured by placing warm water in the jacket between the outer and inner containers. Explosive softened in this way may be handled and used in complete safety. Softening is necessary because, when cold, explosives are not only inefficient but also dangerous. Cases have been known of cold sticks of gelignite exploding when broken in two. "Explosives, detonators and fuses should never be placed near fires, stoves, steampipes or heated bodies,” the authority consulted yesterday stated. “Neither should they be left in a moist atmosphere or in the direct rays of the sun. Extremes in temperature for the storage of explosives or their accessories should be avoided, and smoking when using or standing near explosives is highly dangerous. A good rule is never to resolve a doubt by experiment, but always to consult an expert.” Regulations Should be Studied. He stressed the tact that regulations to ensure safety were in force and should be studied and obeyed by all using any form of explosive. The Public Works Department has issued a pamphlet discussing all phases of the storage and handling of explosives. Some of the advice given is: “Danger and inefficiency lie not only in gelatines that are frozen hard, but also in explosives that are chilled, although they may be still more or less plastic. In au emergency, when blasting must, be done in very cold weather, and properly constructed warming-pans are not available and cannot be obtained, the warming of explosives may be done by putting the cartridges into a thoroughly watertight can with a closefitting lid and setting the can in another vessel containing hot water. In such an instance, care must be taken that the water does not cover wholly the can containing the cartridges. “It is of paramount importance to keep in mind that gelatine explosives are Hable to freeze, to become chilled in cold weather, and no gelatine should be put in shot holes in a frozen or chilled condition. There is great danger in doing so, and, apart from the extreme danger to the workman, it is quite certain that the explosives will not do their work satisfactorily.” An engineer who was consulted, said that placing gelignite on top of a stove was risky, because any shock would explode it, and heating in an oven was even more dangerous, as the nitroglycerine might decompose and give off fumes, the heat being sufficient to cause an explosion. This, lie suggested, was probably what happened at Halcoinlie.

Any form of heat near gelignite was to be avoided, he added. At Nelson some years ago two or three tons were landed on the beach in hot weather. The inspector of explosives would not allow anyone near it for several weeks. There were, however, simple rules which made explosives quite safe to use, and it was surprising that there were accidents. “With reasonable precautions there is no danger,” he said. “Dealers are very good in the way they provide information for purchasers, and there is really no excuse for accidents. Carelessness and ignorance, for neither of which there is excuse, are the main causes.”