[Code of Federal Regulations] [Title 30, Volume 1] [Revised as of July 1, 2002] From the U.S. Government Printing Office via GPO Access [CITE: 30CFR7.69] [Page 28] TITLE 30--MINERAL RESOURCES CHAPTER I--MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR PART 7--TESTING BY APPLICANT OR THIRD PARTY--Table of Contents Subpart D--Multiple-Shot Blasting Units Sec. 7.69 Approval marking. Each approved blasting unit shall be identified as permissible by a legible and permanent marking securely attached, stamped, or molded to the outside of the unit. This marking shall include the following: (a) The assigned MSHA approval number. (b) The maximum blasting circuit resistance. (c) A warning that the unit's components must not be disassembled or removed. (d) The replacement battery types if the unit has replaceable batteries. (e) A warning placed next to the charging connector that the battery only be charged in a fresh air location if rechargeable batteries are used. (f) A warning that the unit is compatible only with detonators that will-- (1) Fire when an average of 1.5 amperes is applied for 5 milliseconds; (2) Not misfire when up to an average 100 amperes is applied for 10 milliseconds; and (3) Not fire when a current of 250 milliamperes or less is applied.