MINE VENTING TECHNIQUES STILL SIMILAR TO THOSE IN PAST, MORE DANGEROUS TIMES

                         Roanoke Times
                 Copyright (c) 1995, Landmark Communications, Inc.

DATE: SATURDAY, February 6, 1993                   TAG: 9302060047
SECTION: CURRENT                    PAGE: NRV-8   EDITION: NEW RIVER VALLEY 
SOURCE: GREG EDWARDS STAFF WRITER
DATELINE: BLACKSBURG                                LENGTH: Medium
MINE VENTING TECHNIQUES STILL SIMILAR TO THOSE IN PAST, MORE DANGEROUS TIMES
A MINING expert used his distinguished professorship lecture to look at the past and future of keeping workers safe underground.
While most Appalachian coal mines are well kept, some - particularly smaller mines - are not, says a Virginia Tech professor of mining.
Some smaller mines ignore ventilation completely unless something goes wrong, Malcolm McPherson said Wednesday at his distinguished professorship lecture.
McPherson, a specialist in mine ventilation, has been named the Massey professor of mining and minerals engineering at Tech.
E. Morgan Massey, chairman emeritus of the A.T. Massey Coal Co. of Richmond and other coal-industry and mine-safety officials were on hand for his lecture.
One of the darkest eras in the history of mining was during the Industrial Revolution in the 18th and 19th centuries. "The loss of life in those underground coal mines was quite horrific," McPherson said. Thousands of miners died each year in explosions.
Shaft-bottom furnaces fed by methane were used to stimulate air flow in 19th century mines. It was an idea that went back thousands of years: The hot air rising out of one mine shaft drew cold air in another.
Miners used candles to see underground and miners called "firemen" covered themselves in wet sackcloth to crawl back in the shafts and burn off the explosive methane at the start of each shift. Their life expectancy was short.
Explosion dangers now are much smaller, but "as we have seen very recently the problem is still with us," McPherson said, alluding to the Dec. 7 explosion in Wise County that killed eight miners.
McPherson comes from a long line of Scottish coal miners; he went to work in the mines of central England in 1953.
McPherson was a miner for five years before entering the University of Nottingham to study mining engineering. He came to Virginia Tech in 1991 and serves as director of the Generic Center for Mine Systems Design and Ground Control, where he oversees much of the university mining research in the United States.
During his recent lecture, McPherson traced the history of mine ventilation for his listeners and made some predictions.
The idea of using air circuits in mines with separate "intakes" and "returns" for air, which still is used today, traces its roots back to 600 B.C., McPherson said. During the Roman times, slave labor was used to waft air along the shafts of mines.
Circular fans first came into use around 1860 to replace the furnaces used during the Industrial Revolution to move fresh air into mines and explosive methane out.
Methane, which many people used to cook with or for heating their homes, only becomes explosive when it is found in concentrations of between 5 percent and 15 percent. McPherson used a coffee can filled with methane during his lecture to show what happens when the gas reaches those levels.
He lighted the methane pouring out of a small hole in one side of the can. The gas burned gently like a stove burner set on low. As it burned, air entered the can from another small hole on the opposite side of the can.
The flame grew smaller as the gas in the can burned off. When the gas to air mixture reached 15 percent, the remaining gas in the can exploded loudly popping the lid off the can. "Imagine this happening in the entries of a coal mine," McPherson said.
In the future, McPherson suggested, there will be an increased interest in controlling underground environments. While the 20th century has been the era of skyscrapers, the 21st century will be the century of underground spaces, he said.
In the next 100 years, people will work in factories underground and after work will patronize subterranean shopping malls and theaters. McPherson also predicted that in 100 years most underground mining will be done by machines, not people, and that we will be mining the moon and asteroids.

by Archana Subramaniam by CNB