|
On this day in engineering history, the River Slope Mine collapsed after the Knox Coal Company tunneled too closely to the mighty Susquehanna River.
The River Slope Mine
Located near Pittston and Port Griffith in Pennsylvania's Wyoming Valley, the River Slope Mine was flooded with 10-billion gallons of water that claimed the lives of 12 miners. Later, the U.S. Bureau of Mines concluded that "the cause of this disaster was the removal of the natural support (coal) in the immediate vein beneath the river where the rock strata was insufficient to support the river".
Coal and Water
On the morning of January 22, 1959, miners from the Knox Coal Company tunneled through rock until the distance between the mineshaft and the river bed was just 6 feet. The company, which had been cited for mining beyond a safety stop line in September 1958, had permission to mine an area about 50 feet inland from the Susquehanna's low water mark. According to the property owner, some 35 feet of rock separated this region from the river and the underlying Pittston vein, a well-mined coal bed.
When the Knox Coal Company tunneled toward the riverbed and beyond the safety stop line, the waters of the ice-laden and swollen Susquehanna rushed into the mine. The main roof overlying the Pittston vein consisted of sandstone, a sedimentary rock with relatively high porosity. The mineshaft's immediate roof was made of slate stone, a rock with a lower water-absorption rate, but the miners trapped inside never had a chance to escape. The collapse of the think rock roof created a 150-ft. hole that resembled a monstrous bathtub drain.
Sealing the Susquehanna
As millions of gallons of water and ice pored into the River Slope Mine, the Knox Coal Company struggled to seal the breach. First, diesel locomotives from the Lehigh Valley Railroad were enlisted to dump 50 gondolas into the gap. Next, thousands of bales of hay, hundreds of railroad ties, and over 400 mining cars were poured into the Susquehanna. Eventually, crews from a consortium of companies installed 2 sinking pumps, 22 deep well pumps, and 16 compressed air driven water-air-lift pumps at various locations. Dams were built, the river was diverted, and tons of clay and rock were poured into the breach. A concrete cap sealed the gap, but deep mining was done in the Wyoming Valley.
Resources:
http://www.msha.gov/District/Dist_01/Reports/Knox/cover.htm
http://www.undergroundminers.com/knox.html
| 
Re: January 22, 1959 – The Knox Mine Disaster
