INVESTIGATIONS OF EXPLOSIVES USED IN MINING. PHYSICAL TESTS OF EXPLOSIVES. The Bureau of Mines at the Pittsburgh experiment station makes physical tests of explosives to determine the safety and efficiency of the explosives for use in coal mines where the presence of inflammable gases or coal dust produces unfavorable conditions to safety. Such tests were first made by the Government in 1908, and in 1909 the total quantity of permissible explosives sold was 8,598,027 pounds. In 1913 the total quantity sold was 18,149,977 pounds. In accordance with the provisions of the act of Congress, establishing the Bureau of Mines, as amended February 25, 1913, fees covering actual costs were charged for tests made for manufacturers of explosives. After a careful consideration of "the actual necessary expenses" involved in testing explosives a schedule of fees for testing coal-mine explosives and another for testing metal-mine explosives were prepared, were later approved by the Secretary of the Interior, and were published in Schedule 1. During the year 10 explosives were submitted for tests to determine their permissibility for use in coal mines; 7 of these passed the required tests and were placed on the permissible list and 3 failed to pass the tests. Three special experimental shots were made with the ballistic pendulum and three experimental shots were made in gallery No. 1 for manufacturers. The total sum collected for the above tests was $1,315. On July 1, 1912, there were 95 explosives on the "permissible list" established by the bureau. During the year 7 explosives were added. to the list and 5 were withdrawn for the reason that they were no longer being manufactured or had shown unfavorable results in field tests, and on June 30, 1913, there were 97 explosives on the list. The testing of explosives during the year included the following examinations and tests: Informal tests to demonstrate the safety features of permissible explosives were witnessed by various organizations and persons, as follows: Sixth Congress of the International Association for Testing Materials, September 12; Eighth International Congress of Applied Chemistry, and a few representatives of the United Federation of Miners, September 18; State mine inspectors, September 19; the Assistant Secretary of the Interior, Maj. Edward P. O'Hern, of the Bureau of Ordnance, State mine inspectors, and others, September 20; Westinghouse Club, of Wilkinsburg, October 26, 1912. The following special tests were completed during the year: 1. Tests of Trojan powder to determine whether it is equivalent in disruptive force to the commercial grades of dynamite. 2. Tests of fuse igniters to determine whether they are safe when used in the presence of inflammable mixtures of gas. 3. Tests of Daniel's safety mining cap to determine whether it will stand immersion in water for a definite period. 4. Tests of trinitrotoluol and ammonium picrate (for the Ordnance Department of the War Department). 5. Tests of four metal mine explosives from Hancock, Mich., to determine their relative disruptive and propulsive effects and quantity of noxious gases evolved. 6. Tests of detonating fuse to ascertain the best method of using it for determining the rate of detonation. 7. Tests of electric detonators to determine the time interval between the detonation of four electric detonators connected in series when the capacity of the firing machine is and is not taxed. 8. Tests of various high explosives to determine the probability of each detonating when thrown on a fire. 9. Tests to determine the rate of burning of black blasting powder. 10. Tests to determine the time interval between the firing of electric detonators of different makes and under different conditions of storage when connected in series and fired with blasting machines of different capacities. 11. Tests to determine the cause of premature shots in August, 1912, in the Arnold No. 11 mine of the St. Bernard Coal Co., Earlington, Ky. 12. Compilation of tests of seven foreign explosives. 13. Investigation of blasting methods in the removal of the "hump" in Pittsburgh, Pa. 14. Investigation of the use of explosives in the Canal Zone and tests to determine the comparative efficiency of the different explosives being used. 15. Investigation of the nitroglycerin explosion March 17, 1913, at the works of the Burton Powder Co., New Castle, Pa. 16. Investigation of the explosion of 600,000 pounds of dynamite, March 7, on the steamship Alum Chine in Patapsco River, Baltimore. 17. Investigation of dynamite explosion at the stone quarry of the A. C. O'Laughlin Co., Belwood, Ill., December 10, 1912. Two bulletins and a technical paper, prepared wholly or in part by the engineer in charge of the physical tests of explosives and his assistants, were issued during the year. A bulletin on "Tests of Permissible Explosives" was submitted for publication. The work described above was in charge of Clarence Hall, explosives engineer. He was aided by S. P. Howell, engineer; H. F. Braddock, junior chemist; and J. W. Koster, A. J. Strane, and J. E. Tiffany, junior engineers. EXPLOSIVES CHEMICAL LABORATORY. The work of the explosives chemical laboratory at Pittsburgh includes the analysis and chemical testing of explosives submitted to the bureau for tests to determine their permissibility for use in coal mines. In addition to such examination of original samples, additional analyses are made of samples collected from time to time in the field, in order to determine whether the permissible explosives sold to consumers are manufactured in accordance with the composition of the samples originally tested by the bureau. All explosives purchased by the Isthmian Canal Commission are before acceptance submitted to analysis and tests by this laboratory. As a result of the investigations made in the laboratory, many of the usual methods employed in the analysis of explosives have been improved and new methods have been devised. The following is a summary of the analyses, tests, and determinations made by the explosives chemical laboratory during the fiscal year 1912-13: Analyses tests and determinations by explosives chemical laboratory. Analyses of dynamite_--- Analyses of mining explosives.. Analyses of black powder.. Analyses of electric detonators__ Analyses of blasting caps (detonators). Analyses of products of combustion of explosives_. Analyses of railroad torpedoes. Analyses of nitrating acid___ Analyses of military shell explosives.. Analyses of safety-lamp igniter compositions-- 297 135 10 30 17 43 3 1 Determinations of nitrosubstitution compounds (experimental)_ Determinations of solubility of nitrosubstitution compounds (experimental)__ Determinations of moisture in explosives (experimental)__ Determinations of nitrogen in nitrosubstitution compounds (experimental) --. Determinations of nitrogen in nitroglycerin and other explosives.. Determinations of melting points of nitrosubstitution compounds____ Determinations of ignition temperature_. 85 44 40 23 4 Physical tests of electric detonators_. Physical tests of railroad torpedoes- 2,034 9 291 9 81 1,215 Heat tests of explosives___ Physical tests of blasting caps (detonators) – Special stability tests of explosives (experimental). Exudation tests of dynamite_-_ Analyses, tests, and determinations not included in the above_. 164 The work of inspecting and testing explosives for the Isthmian Canal Commission occupied approximately the following time (estimated as the work of one man): Analyses and tests of dynamite, 280 days; analyses and tests of electric detonators and blasting caps, 30 days; total, 310 days. The following special reports and investigations were completed during the year: A report on the stability of various explosive mixtures containing nitrosubstitution compounds (for the Bureau of Ordnance, Navy Department); an investigation of the behavior of nitroglycerin when heated under known conditions of temperature and pressure with water in a closed vessel; tests of two shell explosives (for the Ordnance Department, War Department); a report on the presence of explosives in road dust used for stemming; a report on the composition and ignition temperature of two types of safety-lamp friction igniters, and the ignition temperatures of dusts from two types of cerium-alloy igniters for safety lamps; a new method for the determination of chlorates. A paper on "The Quantitative Separation of Nitrosubstitution Compounds from Nitroglycerin " was prepared by A. L. Hyde. During the year a bulletin was published describing the methods used by the bureau in analyzing the more common types of explosives. A bulletin on the analysis of permissible explosives is in course of preparation. The personnel of the laboratory during the year was as follows: C. G. Storm, explosives chemist, in charge of the laboratory; A. L. Hyde and W. C. Cope, assistant chemists; J. H. Hunter and J. E. Crawshaw, junior chemists. CORROSION OF IRON AND STEEL IN MINE EQUIPMENT. An investigation of the corrosion of iron and steel used in mine equipment was continued. The results of laboratory experiments in connection with the development of an electrolytic method for preventing the corrosion of iron and steel exposed to acid water such as is found in mines were reported in a technical paper. The laboratory experiments made in the course of this investigation were supplemented by tests with large steel plates immersed in the water of Monongahela River at Braddock, Pa. The investigation was in charge of J. K. Clement, physicist. TUNNEL METHODS. An examination into the safety and efficiency of the methods used in driving tunnels of the size used in mining was completed, and the results were submitted for publication as a bulletin. A separate report on the precautions that superintendents, foremen, and miners should take to prevent accidents was compiled for publication as a miners' circular. The inquiries relating to safety and efficiency in tunneling were made by J. A. Davis, assistant engineer, under the supervision of D. W. Brunton, consulting engineer. MINING INVESTIGATIONS IN THE LAKE SUPERIOR REGION. Fifty-eight metal mines in Michigan and Minnesota were investigated with reference to special efficiency and safety features, ventilation, mining methods, mine signs, signal codes, and accidents. This investigation showed that most of the large mining corporations in the Lake Superior region are alive to the need of protective devices and warning signs in and about mines and to need of educating miners in the prevention of mine accidents and in rescue and first-aid methods, and that the death rate from mine accidents is beginning to show a gratifying decrease. Some of the smaller companies, however, have not followed the example of these companies, and there is need of bringing the necessity of safety precautions to all miners and operators. Special studies relating to the use of uniform warning signs in mines and to the cause and prevention of mine fires were undertaken. The work was in charge of Edwin Higgins, mining engineer. IRON MINING IN THE UNITED STATES. An investigation of the iron-mining industry was continued during the year. This investigation includes methods of exploring for iron and measuring the ore in the ground, mining methods and costs, efficiency engineering and scientific management at mines, treatment of iron ores, safety measures in mines and sanitary precautions in miners' settlements, mine taxation and, in general, all the questions that arise in the iron-ore industry from the prospecting of a deposit to the dumping of ore at the furnace. This work, which is now approaching completion, is being carried on by Dwight E. Woodbridge. During the year two preliminary reports, one on "Mineaccident Prevention at Lake Superior Iron Mines," and the other on "Sanitation at Mining Villages in the Birmingham District, Ala.,' were completed for publication. A complete bulletin on iron-ore |