Mine Rescue Field Exam From the 2013 Ohio Valley Mine Rescue Contest, Cadiz, OH Progress Indicator: Question 4 of 10 4.  In accordance with 30 CFR §49.6(b)(3), “Mine rescue apparatus and equipment shall be maintained in a manner that will ensure readiness for immediate use. The certification and the record of corrective action shall be maintained at the mine rescue station for a period of _____ and made available on request to an authorized representative of the Secretary.” Choices: three months six months one year five years