CFR > Title 30 - Mineral Resources > CHAPTER I—MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR > SUBCHAPTER K—METAL AND NONMETAL MINE SAFETY AND HEALTH (parts 56 to 58) > PART 57—SAFETY AND HEALTH STANDARDS—UNDERGROUND METAL AND NONMETAL MINES > SUBPART E—Explosives (§57.6000 to §57.6960) > 57.6501—Nonelectric initiation systems.

57.6501—Nonelectric initiation systems.

(a) When the nonelectric initiation system uses shock tube—
(1) Connections with other initiation devices shall be secured in a manner which provides for uninterrupted propagation;
(2) Factory-made units shall be used as assembled and shall not be cut except that a single splice is permitted on the lead-in trunkline during dry conditions; and
(3) Connections between blastholes shall not be made until immediately prior to clearing the blast site when surface delay detonators are used.
(b) When the nonelectric initiation system uses detonating cord—
(1) The line of detonating cord extending out of a blasthole shall be cut from the supply spool immediately after the attached explosive is correctly positioned in the hole;
(2) In multiple row blasts, the trunkline layout shall be designed so that the detonation can reach each blasthole from at least two directions;
(3) Connections shall be tight and kept at right angles to the trunkline;
(4) Detonators shall be attached securely to the side of the detonating cord and pointed in the direction in which detonation is to proceed;
(5) Connections between blastholes shall not be made until immediately prior to clearing the blast site when surface delay detonators are used; and
(6) Lead-in lines shall be manually unreeled if connected to the trunklines at the blast site.
(c) When nonelectric initiation systems use gas tube, continuity of the circuit shall be tested prior to blasting.