Mine explosions remain a threat to underground coal miners, requiring constant
vigilance to prevent accumulations of combustible gasses and dusts and to limit
sources of ignition. Accumulations of combustible dust in coal mines create the
risk of large-scale explosions that can result in multiple deaths and traumatic
injuries. The explosion hazard can be effectively controlled through the
application of rock dust, such as limestone dust, to render inert the
combustible coal dust generated during the mining and transport of coal.
Traditionally, determining when additional rock dust should be applied or
evaluating the effectiveness of existing rock dust application has been limited
to a subjective visual evaluation or to the collection and laboratory analysis
of dust samples-a process that requires days or weeks to identify a hazard.



For decades, miners have been able to monitor the concentrations of methane and
other combustible gasses using handheld, direct reading gas detectors. These
detectors have allowed miners to take immediate action to dilute gasses and
prevent explosions. With this same purpose in mind, researchers at the National
Institute for Occupational Safety and Health (NIOSH) developed a real-time dust
explosibility measuring instrument to provide instant feedback to miners on the
relative hazard of dust accumulations in the mine and the effectiveness of
their rock dusting practices. This instrument, the Coal Dust Explosibility
Meter (CDEM), is a simple-to-use handheld device that provides a pass/fail
assessment of coal mine dust samples. With this device, miners, mine operators
and regulators will have the information necessary to take immediate action to
eliminate an explosion hazard.

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AplusA-online.de - Source: National Institute for Occupational Safety and Health (NIOSH)