Mohave County miner., 1915-01-09
How to Store and Handle Dynamite

are frequently set forth in books and magazines and also in pamphlets issued by the manufacturers of explosives. Nevertheless, the repetition of such di- rections and advice never loses any of its value as safeguard to the lives of miners. In Miners Circular No. 19, which has just been issued by the federal Bureau of Mines, Edwin Hig gins, the author, gives the important facts which one should know in con nection with the prevention of ac- cidents.
 The word dynamite" as used in this circular means that class of explosives in which nitroglycerin is absorbed in or is mixed with other materials. Ordi- nary dynamite consists chiefly of a mix ture of nitroglycerin and such ma terials as wood pulp, sawdust, or some mineral substance. By the use of diff ferent materials and of different methods of mixing, different kinds of dynamite are made, such as the am monia, low-freezing gelatin and grant, lar dynamites.
 Ordinary dynamite of different grades freezes at 40 to 50 degrees F., but the specially prepared low-freez- ing dynamites may be used in tenn peratures above 95 degrees F. without freezing. When heated to about 200 degrees dynamite explodes from shock or blow. Dynamite also ex- plodes from shock or blow at or dinary temperatures, but the violence of the shock or blow required to ex- plode it becomes less as the tempera- ture increases. When dynamite is heated to $50 or 400 degrees it ex- plodes from heat alone.
 When not confined, small quantity of dynamite usually burns without ex- ploding, but if large quantity of it is burned, even in the open, it is likely to explode. Although dynamite when burned in air does not always become highly heated, the experiment is a dangerous one to try. Frozen dyna- mite is different to detonate with a blasting cap," but it is likely to be exploded by friction such as is pro duced by punching hole in it with a metal skewer or by cutting in with a hatchet or axe. Dynamite (especially 40 per cent and stronger) may lose strength if repeatedly thawed and frozen. If dynamite is exposed for long time to temperature of 90 de- grees or higher it becomes more sensi- tive to shock and may lose strength.
 Nitroglycerin is readily taken into mans body through the pores of the skin; it then makes the heart beat faster, and usually causes headache in persons not accustomed to it.
 Concerning the storage of dynamite is a problem for the management; therefore the following remarks apply to small mines or prospects, where the miner himself must take the entire charge of explosives.
 When storing dynamite on the sur face, it is often best to use as mag azine an abandoned drift or other opening on a side hill near at hand; if none is available one can easily be made. Brick or stone buildings are suitable, but are not so cool in summer as an underground storage place. Avoid the use of wooden structures of any kind, for they are liable to catch fire and are often used as targets by thoughtless hunters and others. In selecting storage place, remember that exposure to the heat of the sum- mer sun may make dynamite sensitive and will in time cause it to lose its strength.
 Surface magazines should be well drained and the ground around them cleared of all dry brush and timber. They should be provided with lock and key and should have an easily seen signboard showing that dynamite is stored there.
 If no suitable place can be provided on the surface, small quantities of dy- { namite may be stored underground, in a remote or separate part of the mine , where an explosion will be least likely [