Jan 11, 2015 3 min read

A lengthy report prepared by the University of Pittsburgh on damage caused by underground mine subsidence could be an important document if it leads to better ways to mitigate damage and its recommendations are taken to heart.

Prepared for the state Department of Environmental Protection, the report is the fourth to be completed under Act 54 legislation passed in 1994, which revised the law on subsidence damage and required reports, or assessments, to be done every five years on subsidence impacts.

The report on the latest assessment period, which covered August 2008 through August 2013, and is more than 450 pages, focused in part on the effects of mine subsidence on streams. Among other things, it noted about 39 miles of streams in Pennsylvania were impacted by subsidence caused by underground coal mining during that five-year period.

During the fourth assessment period, 96 miles of streams were undermined, the report said. Of that, 51 miles were threatened by longwall mines, which are only found in Washington and Greene counties. This should make the report required reading for local residents.

“Nearly all reported stream impacts resulted from subsidence associated with longwall mining,” the report states. The impacts included pooling and the loss of stream flow.

Fourteen stream recovery reports, prepared after recovery efforts are conducted, also were filed by coal operators with DEP during the period. Nine streams were released from further monitoring, three remained under review and two had not recovered, requiring the operator to conduct “compensatory mitigation.”

The report also included a follow-up on the third assessment period, during which 55 stream investigations were initiated and 51 resolved. Eight of those streams listed as resolved from the third assessment period, however, were found to be “not recoverable,” the report said.

This report seems to indicate that no matter what efforts are taken to repair damage to a stream caused by mine subsidence, some streams do not recover, at least in the period in which studies were conducted.

The report also considers impacts to land, buildings and water supplies. A total of 1,250 incidents involving subsidence were reported during the fourth assessment period, about the same number as in the previous period.

It is lengthy and appears thorough, but one problem cited by the University of Pittsburgh report makes it difficult to determine whether progress is being made in documenting and analyzing data and addressing subsidence impacts.

It cites the difficulty of obtaining, organizing and analyzing the data, and noted the university’s researchers had to construct a new database to evaluate changes over time. If the agency doesn’t methodically collect and manage the information, obviously, it will be difficult for it to draw any conclusions on the impacts as well as what works in mitigating damage.

A DEP official said the report helps the agency improve its mining program and permitting process.

If a coal operator must mitigate a specific subsidence event, it will help the agency determine the best method to accomplish that. The agency also views it as a tool with which the department can review its programs and consider what might need to be changed. It now has five years to address the problems and implement recommendations included in the report.

We hope DEP makes an effort to do that.