Subsidence is one of the lingering reminders of the long, often bloody, history of coal mining in Northeast Pennsylvania. According to a history of anthracite coal mining compiled by the federal Mine Safety and Health Administration, anthracite mining in the area began in 1775, peaked in the 1910s and steadily declined after.
By 1987, the total weight of anthracite pulled from the ground was less than 10 percent of what it was in 1917.
For residents with long ties to the area, subsidences barely raise an eyebrow. As the earth’s surface settles into the voids below, hundreds of these events occur every year.
Bernard Walko, planning unit engineering manager at the Bureau of Abandoned Mine Reclamation, said between Jan. 1 and June 30, 2013, the department received 105 inquiries regarding abandoned mine lands. He said it received a total of 185 inquiries in 2012, 359 in 2011 and 218 in 2010.
Walko said the number of possible subsidences reported to the DEP fluctuates every year. In years with heavier precipitation, he said, underground water pressure can lead to more subsidences.
The risk of such an event happening to one person is low, said Lawrence Ruane, administrator for the Mine Subsidence Insurance Board. Only one in 2,000 people who take out subsidence insurance policies ever sustains a loss, he said. This explains why only 5 percent of people at risk of subsidence purchase insurance.
“They just think that they’re not going to be that unlucky person,” Ruane said.
Plumbing The Depths
Digitizing the thousands of maps will help the board and the public see what lies beneath their homes or businesses, he said. More complete maps will be especially useful in the anthracite region, which has not been mapped thoroughly.