As of June 2014, violations per inspection hour at U.S. mines were down 19 percent, according to the U.S. Department of Labor's Mine Safety and Health Administration (MSHA), in its monthly impact inspections report.

Decreases across the board

Significant & substantial violations were down 27 percent, unwarrantable failures were down 53 percent and lost-time injury rates were down 9 percent.

Despite the promising trend, federal inspectors still issued 190 citations and eight orders during special impact inspections conducted at 15 coal mines and three metal and nonmetal mines in July.

Extra attention for noncompliant mine operators

The monthly inspections, which began in force in April 2010 following the explosion at the Upper Big Branch Mine, involve mines that merit increased agency attention and enforcement due to their poor compliance history or particular compliance concerns.

"A review of mines receiving impact inspections between September 2010 and March 2014 and having had at least one follow-up inspection shows that these enforcement actions have made mines safer," said Joseph A. Main, assistant secretary of labor for mine safety and health.

Since April 2010, MSHA has conducted 798 impact inspections and issued 12,817 citations, 1,178 orders and 54 safeguards.

MSHA's Monthly Impact Inspection List for July 2014 is available online.