Author Description

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1918 edition. Excerpt:...bulkheads, are sometimes used. Ordinarily it is sufficient to pile the muck closely and carry the tamping on out to the very mouth of the tunnel. i i Fig. 88.--Diagram of.Wiring for Tunnel Blast TAMPING Ordinarily the word "tamping" is used to cover both the act of closing a bore hole and the earthy material used. A better use is to designate the act or work as "Tamping" and the material as "Stemming." ".' Stemming, except for gopher holes and tunnels should be free from stone and grit. For large holes where the weight of the stemming gives the confinement, dry free running sand is good. For other work a moist, easily packed sand, clay or loam is best. Dry light material such as the "Bug Dust" from drills, augers or cutting machines should never be used. Good tamping is one of the prime essentials of successful blasting. Water Tamping.--When a large amount of water covers a charge of high explosives in a "down" hole, further tamping is sometimes omitted, as the water makes fair tamping. When the explosive used has good water resisting power and an adequate supply of water is convenient, it can be used instead of earthen tamping, even though it is not as effective. FIRING By "Firing" is meant the setting off or exploding of blasts. This should never be done until the blaster is sure that all charges are properly loaded and tamped and that all persons or animals are at a safe distance. What constitutes a safe distance must be governed by the individual blast. It is usually safe within a few yards of a subsoil shot, as there is practically no danger of soil or stone being thrown into the air; but boulder, stump, ditch, quarry and many other blasts throw fragments of earth, wood...