One Hundred Years of Federal Mining Safety and Health Research

(permissible) type, whereas by 1929 about 50 percent of explosives used were permissible
[USBM 1932].
Figure 24. Explosion test at the Bruceton Experimental Mine, 1927.
Beginning in 1922, the Bureau studied the breaking of ore and coal by explosives to determine
optimum blasting patterns and timing for efficient and safe blasting in underground mines.
Much of this work was completed at the Bruceton Experimental Mine as well as at two new
experimental mines established by the Bureau at Mount Weather, VA, in 1936 and at Rifle, CO,
in 1945. Research at Mount Weather included studies on drilling and blasting and on methods
for setting industrial diamonds in drills to increase drilling speed and efficiency. The
experimental mine at Rifle studied efficient methods for mining of very thick deposits of oil
shale in western Colorado.
3.1.2 Rock Dusting Research
The possibility of using rock dust to prevent coal dust explosions was recognized as early as
1911 [Rice 1911]. Building on this work, the Bureau began an extensive series of tests, and by
1922 these tests in the Bruceton Experimental Mine verified that rock dust could help prevent
dust explosions [Rice et al. 1922]. Some commercial coal mines were already using rock dust as
a preventive measure as early as 1912 and the practice spread, with manufacturers producing
commercial rock dusting machines by 1930.
The practice of rock dusting spread slowly. By 1930, 8.4 percent of underground bituminous
coal mines were using rock dust, and these mines accounted for 33.2 percent of underground
coal production. By 1940, the underground coal mines being rock dusted increased to only 9.1
percent; however, these mines were responsible for 55.7 percent of underground production.
Thus, the large high production mines were much more likely to be using rock dust.
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