INJURY EXPERIENCE AND WORKTIME BY STATES 
41 
 
man-hours worked within the general groupings of mining and milling industries
were as follows: Coal—West Virginia, 
metal—Minnesota, nonmetalL~~_California, stone—Pennsylvania,
and sand and gravel 
—California. 
 
ACTIVE OPERATIONS 
 The number of active mineral-extractive and processing establishments in
the United States during 1966 are presented in table 1 for each of the general
groupings except for the oil and gas industries. Similar data for 1967 are
not available. 
 Producers and processors of minerals reported 29,256 active mine&, quarries,
pits, 
 
dredges, brine, well and other types of mineral-extractive operations in
1966. The largest numbers of mining establishments were in Pennsylvania (2,463),
Kentucky (1,917), and West Virginia (1,806). Active mineral-cleaning and
processing mills totaled 5,606.