The U.S. Department of Labor's Mine Safety and Health Administration announced that the final rule on Rock Dust was published June 21 in the Federal Register on the maintenance of the incombustible content of rock dust.
The rulemaking can be viewed at
http://www.cdc.gov/niosh/mining/pubs/pubreference/outputid2825.htm.
http://www.msha.gov/MEDIA/PRESS/2011/NR110620.asp