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Show 4 INTER-MOUNTAI- N Notes on Dynamite. MINING REVIEW. bined the product is a safe mixture. Unskilled labor and Impure can be had for less money, but the product of this combination is a mixture subject to decomposition. Decomposition in such a compound is nitro-glyceri- ne Harry A. Lee, Commissioner of Mines of the State of Colorado, contributes the following: Mr. Under the most favorable conditions the manufacture of dynamite is a hazardous business, safety being entirely dependent upon the purity of materials used and the skill and care of the workmen employed. If the manufacture of explosives, as in all lines backed by American ideas and energy, the American product stands Although the first plant was established in this country only a little over twenty years ago, the art has today reached that point of perfection, brought feats of engineering within the range of possibility and exerted an influence upon modern civilization, which entitles it to take rank with the application of steam power. The aim of the various powder companies is to supply a product which can be transported and handled with safety, which will give uniform results in blasting, keep in good condition when properly stored, and, as far as possible, neutralize all poisonous fumes when exploded. The explosives used almost universally throughout Colorado are for compounds having .a base, commonly called by the miner 30 per cent powder or 60 per cent powder, according to percentage of in the mixture. The strength of the American nitro-powdis not, as Is generally for supposed, wholly dependent force upon the amount of nitroglycerine present in the mixture. The pre-emine- nt. nitro-glyceri- ne nitro-glyceri- ne er compound is composed of various ele- ments which in manufacture not only absorb the desired amount of nitroglycerine, but are in themselves an explosive. In blasting, the exploder or cap, which is charged with fulminate of e, mercury, explodes the and the in turn, the remainder of the mixture. A line of experiments, conducted by experts, shows that the force exerted by this combine tion exceeds that of the sum of the three exploded separately. The American dynamite of today is not an accident, but is the result of a long line of careful experiments, conducted by eminent chemists, and demonstrated by practical tests. These tests, aided by great advances In the art of manufacturing, have demonstrated that the products can be handled with greater impunity than many other things common to transportation by common carriers. They have also demonstrated that the safety of the compound is dependent upon purity of materials used and care in mixing. During the past few years competition among various powder companies has been so keen and bitter that gradually but steadily the cost of dyna-mlat-e to the consumer has been reduced. It is a dangerous contest, and a rivalry in which, sooner- or later, If continued, safety will be sacrificed. To be more explicit on this point skilled labor commands a certain price, likewise chemically pure the two being the most expensive parts in the compound of dynamite; com nitro-glycerin- nitro-glycerin- e, - nitro-glyceri- ne practically explosion. Decomposition may not set In for some time, and the great danger of the competition, in the manufacture and sale of dynamite, is that of forcing some of the competitors to use impure or cheaper materials and labor, in order to meet a lower price, and take chances upon decomposition not commencing before the stock thus manufactured is disposed of. This danger point may not as yet have been reached. The older powder companies have much invested and a reputation to maintain; the newer companies have much invested and a reputation to make. From the standpoint of safety, however, the bottom price is very little below the market price of today. Powder should be stored in a dry, cool and well ventilated magazine built for that purpose. A brick or stone magazine is preferable to a frame, both on account of being affected less by sudden changes in temperature and freed from any danger of bullets from careless marksmen. When built of wood the frame or studding should be covered inside and out with boards, and so set that the air can circulate all around, and the inner boards be but little effected by the heat of the hot sun. Caps should not be stored with powder. Regarding the age of powder when powder has had proper care in manufacture and storage, decomposition will not set in. If there is no decomposition there is no chemical change, and under these circumstances powder ten years old or older is just as good and safe to handle as powder ten days old. One of the main sources of accident is from thawing powder, and the only safe plan is the use of heat from hot water. The powder should not be dipped in the water but placed in a watertight vessel and the vessel set in hot water, or a regular powder warmer should be made. These vessels can be obtained from any of the mechanical firms or from the powder companies at nominal cost. Do not place powder under or on a stove, or in the oven. Do not lay on boiler wall or on back plate Do not heat around a blacksmith forge, or over a burning candle. Do not lay on hot sand, or, In short, do not thaw powder with dry of a boiler. heat. Do not consider these precautions unnecessary, or reason that because you have done so many times there is no danger. An explosion is usually fatal, and numberless escapes in no manner reduce the explosive force. Constant care In preparing charge and loading will avoid missed holes. Next to warming powder with quick, dry heat, picking out a shot is the cause of the most fatal accidents. If a hole misses do not be in a hurry to return, and especially If the hole was More accidents are tamped close. caused from supposed missed holes than from actual. A small, sharp rock may be tamped into a piece of fuse, so that the fire will not pass that point for hours; this is often mistaken for a missed hole. The hole is picked out, this particular rock removed, and an explosion follows. To fully demonstrate this, put some clamps on a piece of fuse and see how long it will take to bum by certain points. Long after the fuse is supposed to be out, loosen the clamps and see how quickly it will spit at the other end. Some holes do miss fire and have to be picked out. In these, great care should be exercised to clean down not nearer than 5 Inches from cap, then reload with another charge, and, instead of using a small piece of powder, use plenty. A heavy charge on top may destroy the effectiveness of the lower charge, but it will explode it and get rid of a bad job. If the collar of the hole is simply blown off and the lower charge has not broken to the bottom of the hole, do not drop in a drill or spoon to see how much hole is left; leave it alone as long as possible. The lower powder may have frozen, and all may not have V-shap- ed been consumed. Caps are charged with fulminate of mercury, one of the most violent explosives, and one of the most unstable chemically, and may explode from the slightest jar or least amount of friction. The caps at all times should be stored well away from the powder and at no time in or around a miners pocket. Powder should under no circumstances be stored underground. Poor ventilation with damp air will produce decomposition and decomposition explo- There is practically no danger in transporting powder in cases, and esEven well pecially when frozen. thawed powder will not explode from any of the Jars occasioned by wagon haul or pack train. A case dropped several hundred feet upon rock might explode, but separate sticks would simply break out of the wrapper and no explosion. sion follow. Powder freezes at from 40 to 44 deg F., explodes, when confined, at from 320 to 360 deg. F. From a quick application of dry heat, powder is liable to explode at 120 deg F. A stick of powder heated to 120 deg. F. can be held in the hand with little inconvenience, and this degree of heat is soon reached when placed under or above a stove. That frozen dynamite is liable to explode from heat quickly applied has been demonstrated many times, and to ignorance, or carelessness of this fact, most accidents are due. If you have heated powder about a stove for. years without harm, consider yourself fortunate and stop it. If the warning of those who make the powder has no effect, let the accidents constantly occurring from this cause convince you. If you cannot procure a d lard powder warmer, take a bucket, fill it with powder, and set in warm water. If you have no warm water, put some sharp rocks in the bottom of a larger vessel to keep the smaller vessel off the bottom, surround the inner vessel with water and set two lighted snuffs about an inch long under the big can. throw an ore sack over the whole, and in a short time the powder is in good condition for use and non-appreciat- ion five-poun- |