MSHA issued a Program Policy Letter (PPL) establishing “approval guidelines for communication and tracking devices under Title 30 Code of Federal Regulations (30 C.F.R.) Part 23, Telephones and Signaling Devices, to address the provisions of the MINER Act.”

The PPL explains the guidelines that “are being administered by the Approval & Certification Center when processing applications for approval of communication and tracking products for those underground mines or operations required to have permissible equipment.”

The PPL may be found here.