The federal Mine Safety and Health Administration is publishing a proposed rule tomorrow that could require all mine operators to eventually install safety devices on certain types of mining equipment.MSHA’s proposed rule would phase in a requirement that mine operators use proximity warning devices on their continuous miners—the large machines that scoop coal from the face of the mine. Proximity warning devices are safety features that automatically shut off the machine when miners are too close, and they’re meant to protect coal miners from being crushed by machinery while underground.Since 1984, 30 coal miners have been killed and more than 200 injured in machinery accidents. The hope is that the technology would prevent those. Dave Chirdon is MSHA’s New Technology Manager.“Most mining knowledgeable people understand that this technology can prevent those accidents,” he said. “About the only objection I can imagine would be on a cost basis.”Chirdon says to retrofit an existing continuous miner would be about $25,000 to $40,000, but the machinery new can cost up to $1.5 million.This rule is a step back from what was originally proposed. It only covers continuous miners—rather than all moving equipment in a mine. And MSHA initially wanted to put an Emergency Temporary Standard into place to protect miners while they worked out the kinks.“As we got into the review process there was some feedback received by some other areas, particularly the presidential office, the [Office of Management and Budget], that encouraged us to allow that public comment process to take place before we implemented this,” Chirdon said.The public has sixty days to comment on the proposed rule, and Chirdon estimates the final rule should be published in early spring.