Swaths of Pennsylvania and numerous other states are riddled with outdated and unstable mines, posing a serious threat to the safety of both people and properties due to the risk of sudden collapses. This fear became a grim reality in Westmoreland County, located just southeast of Pittsburgh, where 64-year-old Elizabeth Pollard went missing while searching for a lost cat alongside her granddaughter. The frantic search efforts took a turn for the tragic on Monday evening as a sinkhole developed approximately 20 feet from her parked vehicle, in a region known to be above an old coal mine. Fortunately, her granddaughter was eventually found safe in the car, but Pollard’s situation turned from a rescue mission to a recovery operation by Wednesday, as officials expressed doubts about her chances of survival.
Mine subsidence has caused extensive financial damages across the United States. In Pennsylvania, which boasts a coal extraction history that dates back to the late 1700s, nearly half of the state’s 67 counties have experienced coal mining, and currently, there are at least 5,000 abandoned underground mines. These mines present hidden hazards, which authorities warn can emerge with little to no warning. Nationally, it is estimated that there are about 500,000 abandoned mines, outnumbering those currently in operation, according to data from the federal Mine Safety and Health Administration. These abandoned sites are prevalent, especially in coal-producing regions and western states with a history of mining, leading to numerous fatalities, with some criminals even attempting to conceal victims by discarding them in open mine shafts.
According to Professor Paul Santi from the Colorado School of Mines Geology Department, the sinkhole in Westmoreland County appears to have been caused by a rapid and catastrophic roof collapse of an ancient mine that had been sagging for years. He explained that while gradual sinking can often be monitored using satellite data, unpredictable collapses like this one occur suddenly, turning previously stable ground into a sinkhole overnight. The Marguerite Mine, which authorities suspect is the source of the sinkhole, ceased operations in 1952 and was managed by the H.C. Frick Coke Co. The coal seam sits approximately 20 feet under the surface, a depth that increases the risk for sudden collapses in areas where coal has been extracted, leaving behind large voids that may have filled with air, water, or debris over time.
The sinkhole itself was described as teardrop-shaped, featuring a small opening above a more extensive cave-like space. If the collapse had been deeper, it would have manifested as a cone and taken longer for its effects to be visible on the surface. Various mines once employed support systems such as steel arches to minimize the risk of collapses, while others relied on leaving pillars of coal intact to prop up the roof. Despite these measures, settling can still occur over time, leading to dangerous conditions.
Authorities from the state Bureau of Abandoned Mine Reclamation are expected to inspect the sinkhole once recovery efforts conclude to determine if it was indeed caused by mine subsidence. The dangers associated with old mines are significant, with the U.S. Bureau of Land Management noting that 381 fatalities and 152 injuries occurred at abandoned mine sites nationwide between 2000 and 2013. Often, owners of these mines abandoned them when they became too costly to operate, leaving safety hazards and environmental pollution that must be managed by public agencies.
Tragic incidents often unfold as individuals fall into flooded shafts, wander through unintended underground tunnels, or encounter toxic gases present in many abandoned coal mines. With mine shafts that can extend hundreds of feet below the earth’s surface, many remain unmarked and can present substantial risks. Although state and federal agencies have sealed off numerous old mines, many more continue to be discovered annually, and thorough risk assessments have yet to be conducted on the majority of abandoned mines located on federal lands.
The issue of subsidence is widespread, affecting various regions, as reflected in a recent sinkhole incident in a neighborhood north of Rapid City, South Dakota. Santi emphasizes the challenge posed by increasing population pressure, urging for improved mapping of these mines and advising against construction in affected areas or ensuring awareness of their depths to mitigate the risks of sinkholes. Additionally, millions of gallons of contaminated water, laden with arsenic, lead, and other harmful metals, flows daily from polluted mine sites without treatment.
In Pennsylvania, the agency responsible for managing abandoned mines reported responding to 75 cases of subsidence in the current year alone and a total of 578 since 2017. This issue has long jeopardized homeowners in the state’s historical coal mining regions, prompting Pennsylvania to offer mine subsidence insurance starting in 1961 to protect properties from potential damages. Today, over 62,000 of such policies are active, with the program having addressed more than 2,200 claims.
