Page 28 - Advanced Mine Ventilation

Underground Coal Mine Atmosphere 11

Thus in the case of respirable dust, the generation of dust can be minimized by pre-
treating the coal with water and using sharp cutting bits to cut coal. Next, well-
designed water sprays can be used to suppress the dust at the site. The dust that gets
airborne can be next collected by a scrubber on site. Finally, the remaining airborne
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dust can be diluted to a safe level of less than 1.5 mg/m by adequate ventilation air.
Similarly for methane in coal, the emission of gas can be minimized at the source by
drainage of gas ahead of mining. Water sprays on cutting machines create a good mix-
ing of gas and air. Finally, enough air is circulated to dilute the gas to less than 1% by
volume and render it safe.
For diesel exhaust, the control strategy is as follows:
1. Select engines and fuel (low sulfur) that have a low specific diesel particulate matter emis-
sion, preferably less than 5 gm/bhp-hr.
2. Make the exhaust go over a catalytic convertor, where harmful gases, such as CO are con-
verted to CO 2 .
3. Next, let the exhaust go through a filtration system where most particulates are collected with
an efficiency of 90%e95%.
4. Finally, dilute the exhaust with enough air to render it harmless.

1.5 Enforcement of Ventilation Standards

The final goal of a safe coal mining air environment is achieved by the 3 E’s.
Engineering: The purpose of this book is to provide the engineering control principles.
Education: It is the domain of academic institutions. Technology transfer must be a part of
the education process.
Enforcement: The basic requirement for engineering control must be enforced.

An agency of the US federal government does the inspection and enforcement in
coal mines. It is called Mine Safety and Health Agency or MSHA in the United States.

1.5.1 Mine Ventilation Regulations

Each coal mining country has its own ventilation regulations, but they are very similar.
Large countries, such as the United States, have not only federal regulations that apply
to all states but each state also has its own “state regulations” for local situations that
may not be adequately covered by the federal regulations. State regulations generally
are stricter than federal regulations.

1.5.1.1 US Federal Regulations
Federal regulations for all mining activity are specified in the “Code of Federal Reg-
ulations (CFR)”. It is divided into 50 titles. Title 29 of the CFR regulates tunnel con-
struction work. Title 30 is devoted to mineral resources and is the most pertinent for