Owing to lack of information in regard to the exact relationship between the percussive and the heaving force in particular explosives, this waste, as compared with the quantity required for the work with a properly balanced material, will continue; but it is to be hoped that it will soon be possible to give the mining and quarrying industries suitable information in regard to the properties of the various explosives, so that the railroad contractor and the metal miner may have the same simple and exact means of discrimination between suitable and unsuitable explosives that is now being provided for the benefit of the coal miner.
Another of the important but indirect benefits of this work has been the production of uniformity of strength and composition in explosives. An example of this helpful influence is the standardization of detonating caps and electric detonators. In the early days of the explosive industry, it was apparently advantageous for each manufacturer to have a separate system of trade nomenclature by which to designate the strengths of the different detonators manufactured by him. The necessity and even the advantage of such methods have long been outgrown, and yet, until the past year, the explosive industry has had to labor under conditions which made it almost impossible for the user of explosives to compare, in cost or strength, detonators of different manufacturers; or to select intelligently the detonator best suited to the explosive to be used. After conference with the manufacturers of detonating caps and electric detonators, a standard system of naming the strengths of these products has been selected by the
Testing Station, and has met with a most hearty response. It is encouraging to note that, in recent trade catalogues, detonators are named in such a way as to enable the user to determine directly the strength of the contained charge, which is a decided advantage to every user of explosives and also to manufacturers.
The uniformity of composition of explosives (and many difficulties in mining work and many accidents have been rightly or wrongly attributed to lack of uniformity) may be considered as settled in regard to all those on the Permissible List. One of the conditions required of every explosive on that list is that its composition must continue substantially the same as the samples submitted originally for official test. Up to the present, all explosives admitted to the Permissible List have maintained their original composition, as determined by subsequent analyses of samples selected from mines in which the explosive was in use, and comparison with the original samples.
The data assembled by the Testing Station in regard to particular explosives have also been of great benefit to the manufacturers. When the explosives tests were commenced, comparatively few explosives were being made in the United States for which it was even claimed by the manufacturers that they were at all safe in the presence of explosive mixtures of gas or coal dust. It was evident that, without systematic tests, very little knowledge of the safety or lack of safety of any particular explosive could ever be gained, and, consequently, the user of explosives was apt to regard with incredulity any claim by the manufacturer in regard to the qualities of safety. Owing to lack of proof, this was most natural; and it was also evident that the very slow process of testing, which was offered by a study of mine explosions during past years, was sufficient only to prove the danger of black powder, and not in any way to indicate the safety of any of the brands of mining powder for which this property was claimed. Indeed, one of the few explosives to which the name, “safety,” was attached, at the time the Government experiments were first undertaken, was found to be anything but safe when tested in the gallery, although there is no reason to believe that the makers of this and other explosives claiming “safety” for their product, did not have the fullest confidence in their safety.
The Testing Station offered the first opportunity in the United States to obtain facts in regard to the danger of any particular explosive in the presence of explosive mixtures of gas or coal dust. With most commendable energy, the manufacturers of explosives, noting the early failures of their powders in the testing gallery, began at once to modify them in such ways as suggested by the behavior of the explosives when under test, and, in a short time, returned to the Testing Station with improved products, able to stand the severe
tests required. In this way the Testing Station has been a most active agent in increasing the general safety of explosives, and the manufacturers have shown clearly that it never was their desire to offer inferior explosives to the public, but that their failures in the past were due solely to lack of information in regard to the action of explosives under the conditions which exist before a mine disaster. The chance being offered to duplicate, at the Testing Station, the conditions represented in a mine in the presence of gas, they showed an eagerness to modify and improve their explosives so as to enable them to answer severe mining conditions, which is most commendable to American industry.
In regard to the unfavorable conditions existing in mines in the past, the same arguments may be used. In spite of the frequency of mine accidents in the United States, and in spite of the high death rate in coal mining as compared with that in other countries, it must be said in fairness that this has been the result of ignorance of the actual conditions which produce mine explosions, rather than any willful disregard of the known laws of safety by mine owners. Conditions in American mines are far different from those obtaining in mines abroad, and, as a result, the rules which years of experience had taught to foreign colliery managers were not quickly applied to conditions existing in American mines; but, as soon as the work at the Pittsburg Station had demonstrated the explosibility of the coal dust from adjoining mines, and had shown the very great safety of some explosives as compared with others, there was at once a readiness on the part of mine owners throughout the country to improve conditions in their mines, and to take advantage of all the studies made by the Government, thus showing clearly that the disasters of the past had been due to lack of sufficient information rather that to any willful disregard of the value of human lives.
Another of the indirect benefits of the work of the Station has resulted from its examination of explosives for the Panama Canal. For several years the Isthmian Canal Commission has been one of the largest users of explosives in the world, and, in the purchase of the enormous quantities required, it was found necessary to establish a system of careful examination and inspection. This was done in order to insure the safety of the explosives delivered on the Isthmus, and also to make certain that the standards named in the contract were being maintained at all times. With its established corps of chemists and engineers, it was natural that this important work should be taken up by the Technologic Branch of the United States Geological Survey, and, during the past three years, many millions of pounds of dynamite have been inspected and samples analyzed by the chemists connected with the Pittsburg Testing Station, thus insuring the high standard of these materials.
One of the many ways in which this work for the Canal Commission has proved of advantage is shown by the fact that, as a result of studies at the Testing Station, electric detonators are being made to-day which, in water-proof qualities, are greatly superior to any similar product. As the improvements of these detonators were made by a member of the testing staff, all the pecuniary advantages arising from them have gone directly to the Government, which to-day is obtaining superior electric detonators, and at a cost of about one-third of the price of the former materials.