Actual Answers.
Act: - Answer The federal mine safety and health act of 1977
Active workings - Answer Any place in a coal mine where miners are normally required to
work or travel
qualified person - Answer as the context requires
Rock Dust - Answer Pulverized limestone, dolomite, gypsum, anhydrite, shale, adobe, or
other inert material, preferably light colored, 100 percent of which will pass through sieve
having 20 meshes per linear inch and 70 percent or more of which will pass though a sieve
having 200 meshes per linear inch; the particles of which when wetted and dried will not cohere
to form a cake which will not be dispersed into separate particles by a light blast of air; and
which does not contain more than 5 percent combustible matter or more than a total of 4
percent free and combined silica (SiO2), or where the Secretary finds that such silica
concentrations are not available, which does not contain more than 5 percent of free and
combined silica.
Working Face: - Answer Any place in a mine where material is extracted during a mining
cycle.
Working Face: - Answer Any place in a mine where material is extracted during a mining
cycle. Inby the last open crosscut.
Working section: - Answer All areas of the coal mine from the loading oiunt if the section to
and including the working faces
Air Course: - Answer An entry or a set of entries separated from other entries by stoppings,
overcasts, other ventilation control devices, or by solid blocks of coal or rock so that any mixing
of air currents between each is limited to leakage.
Intake air - Answer Air that has not yet ventilated the last working place on any split of any
working section, or any worked out area, whether pillared or nonpillared.
Return air: - Answer Air that has not yet ventilated the last working place on any spolit of any
working section or any worked-out area whether pillared or nonpillard. If air mixes with air that
has ventilated the last working place on any split of any working section or any worked-out
area, whether pillared or nonpillared, it is considered return air. For the purposes of 75.507-1,
air that has been used to ventilate any working face if such air is directed away from the