Tamp′ing.
1. (Smelting.) Stopping with clay the issues of a blast-furnace.
2. (Military Mining.) Packing with earth, sandbags, etc., that part of the mine nearest to the charge to increase its effectiveness in a given direction.
3. (Blasting.) a. Filling up a blast-hole, above the charge, so as to direct the force of the explosion laterally and rend the rock. b. The material used for the above purpose; it may be fragments of stone, earth, sand, or even water. Lieutenant-General Sir John Burgoyne, of the English Engineers and Inspector of Fortifications, states that the desideratum in tamping is to obtain the greatest possible resistance over the charge of powder; if it could be made as strong as the rock itself, it would be perfection. a. The different materials employed for tamping are: — The chips and dust of the quarry itself. This is what is most commonly used, unless there be stone in it that strikes fire. b. Dry sand poured in loose, or stirred up as it is poured in, to make it more compact. General Burgoyne cites the favorable notice of sand in this connection, in the memoir of the works at Cherbourg, and also by a writer in the Journal of the Franklin Institute. He also cites the experience of General Pasley, of the English Engineers, who condemns sand as utterly unfit. An extended series of experiments were made in the granite of Dalkey, Kingstown Harbor, Ireland, in which sands of various qualities and fineness were tried, as against the baked clay. The results of the experiments were all unfavorable to the sand. c. Clay, well dried, either by exposure to the sun or by a fire. d. Broken brick. It is used in small pieces and dust, and is improved by being slightly moistened with water during the ramming. It is pronounced inferior to the dried clay. Several mechanical devices to assist in tamping have been suggested. The evident one would be a mere plug of a tapering shape, and driven into the hole. The most satisfactory of these devices has been an iron cone, with arrows around it, driven in as wedges. Another plan is a barrel-shaped plug, with a groove for the passage of the fuse. In a third instance, the iron cone was secured by tamping above it.
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| Tamping cones and plug. |
| a, tamping-cone. | b, tamping-plug. | c, tamping-cone. |
