The Mine Safety and Health Administration (MSHA) also released two final rules in the last days of the Clinton Administration. The rules will protect all underground miners from diesel exhaust particulate matter, a health hazard created by diesel-powered equipment.
The rules appeared in the Federal Register on Friday.
Diesel particulate matter (DPM) consists of tiny particles present in diesel engine exhaust that can penetrate into the deepest recesses of the lungs.
Despite ventilation, the confined underground mine work environment may contribute to significant concentrations of particles produced by equipment used in the mine, said MSHA.
Underground miners are exposed to higher concentrations of DPM than any other occupational group. As a result, they face a significantly greater risk than other workers of developing such diseases as lung cancer, heart failure, serious allergic responses and other cardiopulmonary problems, according to the agency.
The new diesel regulations will affect 145 underground coal mines employing nearly 15,000 miners and 196 underground metal and nonmetal mines employing nearly 19,000 miners.
MSHA said the new rules will ensure that miners exposures do not exceed those of other groups of workers regularly exposed to diesel exhaust, such as truck and bus drivers.
Since underground conditions vary between coal mines and metal and nonmetal mines, the regulations take different approaches to reduce DPM exposure to the same level.
The final rule to protect underground metal and nonmetal miners establishes an "interim" DPM concentration limit of 400 micrograms of total carbon per cubic meter of air and, after five years, that level must be reduced to 160.
Under the regulation, metal and nonmetal mines have up to 18 months to reach compliance with the interim concentration limit in their underground operations.
These operators have the option of using engineering controls and best practices to reduce DPM to the required limit.
In underground coal mines, the new rule sets a specific limit of 2.5 grams per hour of DPM for permissible and non-permissible equipment.
These limits will be phased in for an operation''s existing equipment inventory over a 48-month period, but new equipment must meet the emissions limits sooner.
Under the rule, coal mine operators may use a combination of controls to comply with the emission limit.
Annual training for all underground miners exposed to diesel emissions is also included in the rule.
Workers must be trained on health risks associated with DPM exposure, control methods being used at the mine, identification of personnel responsible for maintaining those controls, and actions miners must take to ensure the controls operate as intended.
MSHA is offering compliance assistance and a series of informational workshops throughout the country to assist mine operators in understanding the requirements of the rules.
A compliance guide and tool-box also will be available on MSHA''s Web site at www.msha.gov.
by Virginia Sutcliffe