US Mine Safety and Health Administration assistant secretary for mine safety and health said in a regulatory agenda conference last week the issue can no longer be ignored.

"When you look at the number of deaths that have occurred regarding miners being crushed in these underground mines, and you look at the number of miners that have perished this year in those accidents, I think it's time to act," Main said.

"We can't go into the details of what the regulation is going to entail. The title of the rule as it stands is underground compliance."

The underground compliance rule is one of 11 new standards MSHA will issue proposals on this year.

While some of the nation’s mines already have proximity detection systems installed on continuous miners, there are currently no comprehensive regulations regarding the technology, which includes alerts for pedestrians and operators when an individual enters a hazardous area or “red zone” and also can power down a machine if the person remains in danger.

According to federal data, 70 miners have died since 1984 in incidents involving mobile equipment.

Aside from proximity detection, MSHA is also looking at new rules for coal and silica dust exposure, saying they would make it easier to discipline safety law violators, as well as new requirements for the adoption of health and safety programs by US mines.

Main told media and other members of industry during the conference that enacting any significant policy will take time.

The agency has the ability to issue an emergency temporary standard on mine safety and health issues, but final regulations require a process that includes public hearings and an opportunity for comments and input from industry stakeholders.

"The regulatory process is not something you snap a finger at and you finalize the action tomorrow," he said.

"It's a process that takes time to effectively develop the rule-making action that you're seeking to do."

The National Mining Association told the Associated Press it is wary of hasty regulation development.

"Many of the major new proposals rest on technical studies that require significant review. That's why we are concerned about the speed at which this is being done," spokesperson Carol Raulston said.

"It's challenging our ability to do the kind of rigorous analysis that can really improve mine safety. That makes everyone uneasy."

The US coal industry recorded 48 deaths in 2010 – the highest level since 1992. Nine of them were classified by MSHA under Powered Haulage.