MSHA has posted a hazard alert to call attention to injuries that have occurred in 2010 that involve machinery.  A total of 200 dfpersons were injured working around machinery, representing 12 percent of all injuries in the aggregates sector that year, according to the alert.  Best practices include de-energizing power and blocking equipment against hazardous motion before performing maintenance.  Miners are also advised to follow lockout/tagout procedures for all types of energy systems and to inspect machinery prior to use for defects.  If defects are found, the machinery should be properly removed from service immediately.  The alert is a product of an alliance between MSHA and the National Stone, Sand and Gravel Association.