Permitted mining explosives—

Monobels. Brit permitted mining expls made by Nobel s Explosives Co (Refs 1, 2 3) ... 

Non-Permissible (Amer) or Non-Permitted Brit) Explosives. See under Commercial or Industrial Explosives in Vol 3, C435-R to C437-R, and Coal Mining Explosives, Testing for Permissibility in Vol 3, C368-R ff... 

D. Permitted special explosives. They may be used in coal mines where the content of methane in the air is less than 1.5% and in mines where particularly sensitive coal-dust occurs. 

Further development of expls safe against firedamp and/or coal dust will be discussed in section II of this item, entitled Coal Mining Explosives, Permissible. In section I, which follows, are described commercial expls which are not permitted in gaseous and/or dusty coal mines, but can be used for many other purposes... 

Coal Mining Explosives, Permissible (Permitted in GtBritain). This term applies to explosives which, because they have passed special prescribed tests, can be used in coal mines eontg firedamp and/or coal dust. These tests are described under COAL MINING EXPLOSIVES, TESTING FOR PERMISSIBILITY- Approved expls will not ignite expl mixts of firedamp, coal dust 8t air, when used under prescribed conditions. 

Compex. One of the Brit "permitted mining expls which are designated as EqS (equivalent in safety to sheathed explosives). It is listed in Ref without giving the composition Ref Taylor Gay (1958), 96... 

Current Non-Permitted Explosives (Brit). See under Coal Mining Explosives in this Volume and in the books of Taylor (1952), p 14 and of Taylor Gay (1958), p 26... 

Oynobels. A series of British mining explosives, of which the older type passed the Rotherham Gallery Test and was on the British Permitted List K chlorate 27, NG 32.5, Collod Cotton 0.7, Amm oxalate 29.5 woodmeal 10.3%. Its swing by Ballistic Pendulum was 2.6l inches compared with 3.27 for "Standard 60% Gelignite (Power... 

U.S S.R. mining cxpU>sives Permitted in sulphur mines and oil fields Modern Japanese mining explosives... 

All the above considerations lead to imposing a limited storage time on mining explosives. In Poland ammonium nitrate permitted explosives should be used within 114-3 months from the production date. Non-permillcd ammonites... 

Permissible or Permitted Explosives. In many coal mines there is a continual evolution of methane (firedamp) into the air of the workings. 

From the days of Nobel to about 1950 the scientific basis of commercial explosives remained relatively unchanged, although continuous and numerous improvements in manufacturing methods occurred throughout the world. There were, however, many advances in military explosives, note of which will be made later. These advances were, of course, largely due to the two world wars, which occurred since the death of Alfred Nobel. There were also many advances in the development of permitted explosives designed for use in gassy coal mines. 

It will, therefore, be seen that the best and safest practice is to use in each situation in the coal mine an explosive which is best adapted for the operation in hand. The use of unnecessarily weak explosives, even though apparently safer in some tests, is often a disadvantage and can be dangerous. These considerations have led to the development of a series of types of explosives suited for particular purposes in coal mines and subjected to tests relevant to their individual uses. Thus, in Britain there are now five classes of permitted explosives. In Germany there are three classes. In the U.S.A. geological conditions are different and the hazards are less than in Europe, and it has been possible to work throughout with the strongest types of permissible explosives. 

It was early recognised that an explosive is more hazardous in a coal mine if it is fired in a borehole from which the stemming is omitted or blown out early by the explosive than if it is fired in a properly stemmed hole and does adequate work in bringing down rock or coal. The tests which led to the original permitted explosives, now called P1 explosives, were therefore designed to test the product under these conditions. 

It must be remembered that methane can be liberated in a coal mine, not only in the coal itself, but in the nearby stone. It is therefore necessary to use permitted explosives, both in and near a seam of coal. Further, before any shot is fired in a coal mine, tests are made for the presence of methane in the air by means of a safety lamp. This safety lamp is the well-known Davy lamp and an experienced operator can judge the presence of methane in the air from the appearance of the flame. Tests are made... 

The method of mining is somewhat like driving two sets of tunnels at right angles through the strata. Most mines of this type do not present any hazard from methane and therefore non-permitted explosives can be used. The selection of powder or gelatine type of explosive depends on the nature of the rock and particularly on the wetness of the mine. 

Permitted Explosive. An explosive which is authorised for use in gassy coal mines. 

The U.S. 3.5" high explosive antitank rocket (or similar rockets used by other modem military forces) can be cannibalized or altered and used in a variety of improvised techniques. It can be placed as a shaped charge or land mine or it can be launched either electrically or nonelectrically without use of the rocket launcher. Such improvised firing offers the advantages of rigging the rocket as a booby trap or, at least, permitting the operator to be well out of the area before the rocket fires. 

At that time, Dynamit Nobel A.G., still in a healthy over-all financial condition, was permitted by the Treaty to make explosives for mining. The parent company could have carried Rottweil without staggering, or put it to work on fibers. But this latter enterprise would compete with Farben, and that may have forced the decision to sell. Was Farben s acquisition of Rottweil really the opening gun in the later Farben campaign which swept across Europe If it was, Gajewski would not freely admit it ... 

Summary of Landmine Flux Results Since no one has devised a method of directly measuring the flux of explosive molecules from a mine, whether in situ or in the laboratory, several laboratory measurements have been reported in which the mine was placed in a sealed container, surrounded by soil, water, or air. The concentrations of explosive molecules in the surrounding media were then measured at intervals of several days and the flux inferred from the total concentration divided by the elapsed time. This likely provides the best estimate that can be expected. The various measurements have substantial variation, depending on the techniques and media used. Phelan and Webb describe several experiments [1, pp. 23, 24], It appears that a reasonable expectation of flux of explosive compounds from a buried landmine that move into the surrounding soil will be in the range of 1 to 200 pg/day. There are some complications, of course, since the surrounding soil produces a level of resistance, or back pressure, to the flux of the molecules. While the mechanisms are complex, the net effect is that wet soil permits a lower diffusive flux than dry... 

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