NIOSH looks ahead

WITH sole responsibility for all health and safety matters in all US mines, health agency the National Institute for Occupational Safety and Health (NIOSH) handles a veritable potpourri of research projects.

Staff Reporter

These range from the design of equipment for injury prevention, dust and silica control, and hearing loss prevention to new methods of hazard detection in mines and education for effective mine emergency responses.

NIOSH researchers spoke to ILN about some current projects.

George Bockosh, senior scientist for the Pittsburgh lab, argues that it is important for NIOSH to anticipate future trends in technology, public policy and demographics.

"The future will mean making adjustments mandated by new equipment and mining methods and the influx of new and less experienced workers,” he said.

In recent years, one of NIOSH’s major research contributions into longwall mining technology has been in the design of secondary roof supports and lingual shields. NIOSH’s world-class Safety Structures Testing Laboratory houses the Mine Roof Simulator, a unique load frame designed to simulate weight and movement of overburdened rock masses.

Researcher Tom Barezak, who works with major equipment manufacturers such as DBT and Joy Mining Machinery during the development phase of new support systems, said: "Our goal is to prevent catastrophic rock falls from occurring."

The simulator, according to Barezak, is the largest multi-axial load frame in the world and is the only one in North America where this kind of testing can be done.

A rigorous testing program developed by Barezak simulates the real world environment, allowing manufacturers to conduct development testing, and identify and correct design deficiencies with prototype systems before the systems are commercialised.

The testing facility, in Barezak's view, has had a huge impact on the mining industry. "We have literally changed the way longwall tailgates are supported, with nearly 20 new support systems evaluated and commercialised through this program."

Much has changed over the last five or six years. In the mid 90s, support systems in longwall tailgates in US mines were in some form of wood cribbing or timber posts. Today they are being replaced rapidly so now only 25% of tailgates are supported by conventional wood cribbing.

Barezek lists several reasons why there has been a worldwide movement to newer, better support concepts.

First, the timing was right. Timber prices were going up, Western US timber was in short supply and, if available, the quality was spotty at best. This lead to the development of the CAN support, a thin walled steel container prefilled with entrained concrete before shipment to the mine. The CAN is now standard in the Western US.

Second, mine operators wanted systems that can be installed quickly and with little manual effort. This was prompted by concerns over the aging of the work force as longwall productivity has increased. Hence, less time available to install the supports and a way to avoid possible injuries incurred during installation of supports.

Third, coal mine operations have taken a page from South African gold mines where deep cover and dynamic loading due to blasting and seismic activities required better support system technology. Advances in South Africa have been modified for use in US coal mine operations.

Barczak concluded. "Today support manufacturers and mine operators are much more progressive in selecting what works best as opposed to meeting minimal support requirements."

One of the health areas specifically targeted by NIOSH is hearing loss problems, under Ed Thimons, branch chief of the Health Branch in Pittsburgh.

"We operate a hearing testing van that travels around the country visiting mine locations. In 2000, we had the van at 13 sites conducting the tests."

The van has four testing booths and miners are tested at either a mine site or at a United Mine Workers union hall. The hearing tests, administered by professional audiologists, take about 45 minutes and to test all the miners in an area visited by NIOSH normally takes about a week.

Thimons says miners are consulted on how the quality of their life can be improved when they avoid hearing loss. Miners who have contracted hearing loss cite living problems - they have to play the TV at high volume; they can't go to a movie because they can't hear the sound; their wives can't leave the children in the care of the miner father because he can't hear them cry.

While the testing van can detect hearing problems, NIOSH goes beyond that: they monitor equipment used in longwall mines to determine how much noise the equipment generates.

"We want to find out not only how much noise the equipment makes, but also to monitor the miner's noise exposure and correlate the miner's noise exposure to the equipment noise,” according to Thimons.

This correlation is established by conducting time/motion studies for the miners.

"In this way, we can relate the miner's exposure to his position relative to noisy equipment."

From that, Thimons says, NIOSH can look and see if there is any administrative control that can be implemented to lessen exposure.

"It also tells us where engineering controls are most needed."

Thimons says the hearing loss program was started several years ago, but was fully implemented two years ago when the testing van began operating and several other hearing loss prevention projects got underway. Last year the program attained high visibility when the van logged thousands of miles conducting hearing tests and several mine noise surveys were conducted to evaluate equipment noise levels and their impact on hearing loss.

The increased effort in hearing loss prevention coincided with new Federal noise regulations that became operative September 1, 2000.

David Byrne, another NIOSH researcher in Pittsburgh reports on a five year joint study the agency is conducting with Penn State University. The focus is to draw ideas and approaches on solving hearing problems in other industries and test how they might apply to the coal industry.

Some solutions are simple: inexpensive noise monitors in mines to warn workers when noise levels are too high and the testing of hearing protective devices that allow miners to communicate.

During fiscal 2000, NIOSH listed 13 research projects that involved 72 specific areas of study by researchers.