As 2014 draws to a close, there have been 15 coal mining related deaths, the previous record being 18 in 2009.

Federal mine safety officials have credited the changes they’ve made since the UBB disaster, pointing to more aggressive use of team inspections at problem sites and other measures.

Following UBB, which killed 29 people when worn and broken equipment sparked a build-up of methane and coal dust, the US Mine Safety and Health Administration set up a list of mines with a pattern of violations and targeted them.

Inspectors went to the sites, which at first numbered 51 mines and 42 coal operations but have now been reduced to 12 mines, six of them coal-related.

In total, the agency has conducted more than 830 impact inspections since the operations began.

“I do think we’re seeing a cultural change in the mining industry that’s for the better,” Mine Safety and Health Administration official Joseph Main told the Washington Post.

Also thought to be a cause in the drop in deaths is the closure of a number of coal mines around the country.

The number of coal mines in the US fell from 1944 in 2010 to 1701 last year, according to the MSHA.