The Mine Safety and Health Administration has released its preliminary fatality data for last year.Thirty-six miners died on the job last year—19 of them in coal mines. The federal government has been keeping records for more than a century, and 2012 was the second-lowest year for fatalities on record. The only year that was lower was 2009, when 35 miners died.Five of the miners that died on the job last year were from Kentucky, and seven were from West Virginia. The leading causes of death were from machinery and conveyer belt accidents.MSHA estimates that three of last year’s deaths could have been prevented by proximity detection systems, which are designed to automatically shut off machines when people get too close. The agency issued a proposed rule requiring the devices in 2011, but still hasn’t finalized it.