Circuit testing.

§ 57.6407 Circuit testing. A blasting galvanometer or other instrument designed for testing blasting circuits shall be used to test the following: (a) In surface operations— (1) Continuity of each electric detonator in the blasthole prior to stemming and connection to the blasting line; (2) Resistance of individual series or the resistance of multiple balanced series to be connected in parallel prior to their connection to the blasting line; (3) Continuity of blasting lines prior to the connection of electric or electronic detonator series; and (4) Total blasting circuit resistance prior to connection to the power source. (b) In underground operations— (1) Continuity of each electric detonator series; and (2) Continuity of blasting lines prior to the connection of electric or electronic detonators. [61 FR 36801, July 12, 1996, as amended at 85 FR 2027, Jan. 14, 2020] Nonelectric Blasting—Surface and Underground