Steps to improve safety in mines seem to be making a difference. Federal regulators say last month they found the fewest violations yet, since they began special inspections at problem mines.
The Mine Safety and Health Administration says it inspected eight coal mines and four metal or nonmetal mines in march, and issued a total of 155 citations and two orders.
These impact inspections began after the upper big branch mine explosion killed 29 men in West Virginia, three years ago this month.
MSHA director Joe main says there are fewer chronic violators today, and death and injury rates are at all-time lows.