(Kitco News) – Preliminary data from the U.S. Department of Labor’s Mine Safety and Health Administration show that U.S. mine fatalities were the lowest ever recorded in 2015.

The agency reported this week that 28 miners died in work-related accidents at the nation’s mines during 2015, down from 45 in 2014.

“The figure represents the lowest number of mining deaths ever recorded and the first year that mining deaths dropped below 30,” the government said.

Eleven deaths occurred in coal mines, with three in Pennsylvania and two each in Kentucky, Illinois and West Virginia. One each occurred in Alabama and Virginia. The leading causes were powered haulage and machinery accidents, which accounted for six deaths, the government said.

Of the other 17 deaths in metal and nonmetal mining, four occurred in Nevada, followed by Missouri with two, and one each in California, Florida, Georgia, Iowa, Massachusetts, Nebraska, New Hampshire, North Dakota, Ohio, Pennsylvania and Virginia. The leading cause of death at these mines was machinery accidents, which led to five deaths, followed by falling materials that killed four miners, the Labor Department said.

“While coal-mine closures had some effect on the historic low number of mining deaths, actions by MSHA (Mine Safety and Health Administration) and the mining industry to improve mine safety have been a major factor,” said Joseph A. Main, assistant secretary of labor for mine safety and health.

Main cited enforcement efforts, including inspections that address problem mines and retooled procedures for “pattern of violations” that target mines with chronic violations, along with compliance assistance, training and outreach efforts to the mining industry.

“While record-low numbers have been achieved, we are mindful that things could change in a heartbeat if we let down our guard. There is still much more to be done to ensure that miners go home after every shift, safe and healthy,” Main said.

By Allen Sykora of Kitco News; asykora@kitco.com