not provided, the excess supply should be returned to the magazines from which it was distributed. Explosives, detonators, and fuse left in the mine are likely to absorb moisture and become unreliable, as well as being a hazard if left lying around. TRANSPORTATION OF EXPLOSIVES, DETONATORS, AND FUSE When a shipment of explosives is unloaded from a freight car or truck and put in a storage magazine, or when a supply is taken from a magazine for use, certain precautions should be observed. Any sparks, fire, or friction that would cause intense heat might start an explosion; therefore, sparks or flames must be excluded from the vicinity; men should never smoke while handling explosives or working near them; and no matches or smoking materials should be carried by such men. Cases of explosives should always be lifted and set down carefully and should never be slid one over another or dropped from one position to another. REQUIREMENTS FOR VEHICLES CARRYING EXPLOSIVES Automobile trucks used for transporting explosives should be sufficiently strong and in good repair; the brakes and steering mechanism should be in effective working condition; there should be no accumulation of oil or grease, and the fuel line and tank should have no leaks; the electric wiring should be well-insulated; and two suitable fire extinguishers should be provided. The floors of such vehicles should be tight, and any exposed metal on the inside of the body that might come in contact with any package of explosives should be covered with wood or other nonsparking material. Covered vehicles are preferable; if open bodies are used the cases should not be piled higher than the covered sides, and a fireresisting tarpaulin should be placed over the load. No metal tools, carbide, oil, matches, firearms, electric storage batteries or any flammable substances, acids, or oxidizing compounds should be carried with explosives. Vehicles transporting explosives should be conspicuously marked on the sides and ends with the word "Explosives" or display a red flag clearly lettered "Explosives" or "Danger." Explosives should not be transported in any pole-type trailer, nor should any such trailer be attached to a vehicle hauling explosives. Vehicles transporting explosives should be driven only by authorized persons of reliable character; no unauthorized person should be allowed on them. Such vehicles should be kept under full control and no unnecessary stops made; they should not be taken inside a garage for repairs or other purposes. Vehicles transporting explosives should not be left unattended at any time except while making actual deliveries. Motors should be stopped before explosives are loaded or unloaded. The transportation of explosives over public highways is regulated by the Interstate Commerce Commission; many of the foregoing are among the regulations established by that body. Dangerous emergencies arise if vehicles by which explosives are transported are not maintained and operated according to the regulations given. A truck operated by an explosives dealer was carrying a full load on a main highway when the driver discovered that it was on fire. He was able to turn off on a side road and into the middle of a large field without delay. Jumping from the cab, he found the fire too large to combat with an extinguisher and realized that his duty was to keep spectators and volunteer assistants at a safe distance. Fortunately, this effort was successful, and when the truck exploded a few minutes later no one was injured. The fire was thought to have started in the gasoline line from the tank to the engine. In another State, two trucks loaded with explosives were traveling close together when the driver of the leading truck noticed that the other truck was on fire. He stopped quickly to warn the other driver of the fire, and a collision occurred. The second truck left the road, turned over, and exploded; the driver and his relief man on this truck were killed. HANDLING EXPLOSIVES The transportation of explosives from the storage magazine to the places where they will be used either on the surface or underground. should be in accordance with the same general principles to be observed in all phases of the handling and keeping of explosives. Briefly stated these principles are: 13 Explosives and detonators should be kept apart until the charge is loaded. When working conditions permit, they should be transported in separate conveyances or carried by different men; in any case, they should be placed in separate insulated containers. High explosives and detonators should be handled carefully at all times to avoid shock and friction. Explosives and detonators should be protected from flame, sparks, or extreme heat. They should be protected from moisture. Wires of electric detonators, if not short-circuited, should be kept from contact with stray electricity or electrically charged surfaces. TRANSPORTATION UNDERGROUND Two factors influence the quantity of explosives that should be taken underground at any one time: (1) In most cases, the quantity stored in the mine should be as small as possible; and (2) the time spent in transporting the explosives and the number of trips should be reduced to a minimum. In shaft operations, explosives in the original containers usually are lowered at a suitable time when there will be the least conflict with the movement of other materials or supplies and very few men will be in the vicinity of the shaft or stations. Some mines set aside a specific time for lowering explosives, during which period all hoisting of rock is discontinued; this rule applies to both two- and three-compartment shafts. Men do not ride with explosives, loading at the surface and unloading below being done by different men. Supplies of explosives left at shaft collars or level stations should be moved ahead as soon as possible; previous notice of such deliveries should always be given. Where explosives are taken into the mine in a car, a covered, preferably insulated, explosives car should be provided. The car body should be so constructed that no metal will be exposed on the inside, and it should be lined with wood, rubber, or other insulating material (figs. 7, 8, and 9). A rubber-lined steel car having a capacity of 24 boxes 13 E. I. duPont de Nemours & Co., Blasters Handbook: 1942, pp. 70-71. of dynamite, and used at a West coast gold mine, is shown in figure 10. Explosives and detonators should be hauled on separate trips, or the detonators should be in an insulated container safely separated from the explosives; in the latter case at least 1 empty car should be between the explosives car and an electric locomotive, and such trips should be pulled and never pushed. FIGURE 7.-Insulated car for transporting explosives into mine. Explosives cars should never be taken into the mine with a man-trip, and explosives or detonators should not be transported on a man-trip. A trip with explosives should not follow a man-trip closely, but should move at a time when men will not be congregated on haulways or at shaft stations. Some mines reserve a definite time for the movement of explosives in the mine, and the route used is cleared of other trains or cars. Explosives should be taken from one magazine to any other with as little delay and handling as possible. A truck with side boards and used for bringing explosives to a level magazine is shown in figure 11. Where explosives or detonators are not transported in the original containers they should be brought into the mine or taken to the working places in separate insulated containers. Canvas bags are used widely for carrying loose explosives to working places, and where the conditions do not favor the use of rigid containers, specially constructed strong bags with straps or handles may be suitable for this purpose. A plastic container for carrying electric detonators to the face is shown in figure 12. Capped fuse should be carried in insulated containers separate from those containing explosives. Carrying fuse and detonators in canvas bags is much better than simply in an unprotected roll but less safe than in a rigid container. TRANSPORTATION FOR SURFACE WORK Most of the recommendations given for the transportation of explosives to a magazine apply in surface work to their transfer from the magazine to the drill holes. Detailed regulations for quarry blasting have been adopted by representatives of cement and quarry industries, explosives manufacturers, and the Bureau of Mines, which cover safety in open-cut blasting rather completely. 14 The following important provisions of these standards relate to handling of explosives supplies in loading boreholes: Explosives and detonators should be brought to working places in 14 National Safety Council, Storage, Handling, Transportation and Use of Explosives-Standards for Safety in Quarry Operations-Cement and Quarry Section: 1944 revision (in press). Explosives SIDE ELEVATION END ELEVATION FIGURE 8.-Detailed sketch of large insulated explosives car. FIGURE 9.-Detailed sketch of small insulated explosives car. Note: Interior of car is lined with rubber mat covered with tongue and groove flooring the original containers or in separate insulated containers and kept there until removed for placement in drill holes. Capped fuse should be carried in covered insulated containers separate from those containing explosives, but single containers may be used if detonators and explosives are separated by a substantial partition. Explosives should not be transported on the quarry property, handled, or used immediately before or during an electrical storm. 921 |