The Mine Safety and Health Administration says 36 miners died in 2012 -- 19 in coal mines and 17 in metal and nonmetal operations.
The safest year was 2009, when fatalities hit a low of 35.
But MSHA Chief Joe Main says more needs to be done to prevent injuries, illnesses and deaths.
In all, eight of those killed had less than one year of experience in their mines, and 13 had less than five years' experience in their particular job.