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Show Liquiidl Oxygen Is Cheap Explosive considerable first cost, and this plant must be kept running regularly to obtain ob-tain low cost explosive, as the main cost is in the power used. That the power of liquid oxygen as an explosive Is favorably comparable with other explosives Is shown In the fact that 6,300,000 pounds of liquid oxygen are equal to 8,000,000 pounds of dynamite. One of the Interesting features of the high development of this explosive In Germany has been the designing of small portable liquid oxygen-making plants to produce three liters an hour. Such plants have been constructed to move about on trucks, making the material ma-terial much more available for small operators. U. S. Bureau of Mines Recommends Recom-mends It for Use in Non-Gaseous Non-Gaseous Mines. Washington. The use of liquid oxygen oxy-gen as an excellent and cheap explosive explo-sive In salt, metal and other nongaseous nongas-eous mines and In quarry and other outside blasting, Is recommended by the United States bureau of mines after a series of tests. Preliminary experiments In this novel explosive, conducted at the bureau's experimental experimen-tal station at Pittsburgh, Pa., Indicate that it may be used to advantage where dusts and gases are not present, pres-ent, but is especially useful elsewhere In lessening the cost of blasting. While liquid oxygen has not been used in this country so far for this purpose, it Is already widely used In Mexican mines; has been employed In large quantities In the Upper SUeslan mines of Germany since the war, and bus been adapted to tunnel work. Iron mining, subway and excavation work In cities In that country. It was used not only in Germany but In the French Iron mines of Lorraine after the der-man der-man seizure, and applied by them also to the destruction of French steel plants. French ofllclals of the Brley Iron district believe the explosive has come to stay, and the bureau is conducting con-ducting negotiations with Alaskan companies for Its adoption there. I Production Cost Low. An advantage Is that It can be prepared pre-pared on the Job at low cost after the erection of con. pressing plants, which Will make It of especial value In Alaska. As liquid oxygen can be made et the place of consumption, dangers common to the transportation of other explosives can be done away with. Low production cost, lessening the cost per unit of material blasted, Is another advantage. In the use of liquid oxygen explosives explo-sives there is pructlcally no danger of premature ignition, It was found. The danger of misfires, too. Is eliminated by a wait of 30 or 40 minutes after the fuse la lighted, when practically all of the oxygen will have evaporated. Another An-other advantage Is the elimination of the danger of unexploded sticks In shoveling and subsequent handling of coal or ore going out of the mine. Other sources of dunger avoided are the handling and thawing processes such as are necessary with frozen dynamite, dy-namite, and the hazard from lightning or fire when stored. More Power Than Dynamite. But there are certain disadvantages tn the use of this explosive, the bureau bu-reau says. Because of Its rapid evaporation evap-oration liquid oxygen must be used quickly and within a definite time after the hole Is charged, thus limiting limit-ing the number of holes that can be fired simultaneously, although In Germany Ger-many as many as 23 have been flre-J at once. Its use virtually requires the Installation of a llquefing plunt at |
