MSHA - Code of Federal Regulations - 30 CFR 56.6902
30 CFR § 56.6902
(a) Where heat could cause premature detonation, explosive material shall not
be loaded into hot areas, such as kilns or sprung holes.
(b) When blasting sulfide ores where hot holes occur that may react with
explosive material in blastholes, operators shall--
(1) Measure an appropriate number of blasthole temperatures in order to assess
the specific mine conditions prior to the introduction of explosive material;
(2) Limit the time between the completion of loading and the initiation of the
blast to no more than 12 hours; and
(3) Take other special precautions to address the specific conditions at the
mine to prevent premature detonation.
[58 FR 31908, June 7, 1993; 58 FR 69596, Dec. 30, 1993]
NOTE: At 58 FR 69596, December 30, 1993, the effective date of §56.6902(b) is
stayed until January 31, 1994.