GroundRules
30 CFR 57.6406: Duration of current flow.
Where this section sits in the code
- Title 30—Mineral Resources
- CHAPTER I—MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR
- SUBCHAPTER K—METAL AND NONMETAL MINE SAFETY AND HEALTH
- PART 57—SAFETY AND HEALTH STANDARDS—UNDERGROUND METAL AND NONMETAL MINES
- Subpart E—Explosives
If any part of a blast is connected in parallel and is to be initiated from powerlines or lighting circuits, the time of current flow shall be limited to a maximum of 25 milliseconds. This can be accomplished by incorporating an arcing control device in the blasting circuit or by interrupting the circuit with an explosive device attached to one or both lead lines and initiated by a 25-millisecond delay electric detonator.
Collected 2026-08-27T02:25:24Z. Source file · JSON