Coal set the stage for natural-gas free-for-all

By Stephen P. Kunz

The current wave of Marcellus Shale gas drilling has many Pennsylvanians worried about the impact on their water supplies - understandably so. The state's natural-gas industry faces significantly less environmental regulation than the coal industry does, but its potential repercussions are at least as serious. Gas reserves underlie most of the commonwealth, so gas drilling can be expected to span a much greater area than coal mining, which is now largely confined to 10 southwestern counties.

There is an important lesson to be learned from Pennsylvania's experience with coal mining. A few decades ago, a relatively new, high-extraction mining technology was arriving on the scene. Called "longwall mining," it allows the removal of huge blocks of coal - 5 to 6 feet thick, several miles long, and up to 1,600 feet wide.

Extracting that much coal causes the ground at the surface to literally collapse, in a phenomenon that has been aptly compared to a slow-motion earthquake. This has damaged buildings and infrastructure and has harmed streams, aquifers, and waters that were supposed to be protected under state law.

Longwall mining is about maximum extraction. The room-and-pillar mining technology that was used in Pennsylvania for nearly two centuries just wasn't profitable enough for some companies. It left more coal in place, which also happened to prevent the earth above from collapsing.

Causing surface collapse had been specifically prohibited by Pennsylvania law since 1966. But in 1994, the General Assembly changed the law to permit the damage that longwall mining inevitably causes. The amended law (known as Act 54) required remedies for certain damages, but the remedies don't come close to addressing or restoring all the damage that occurs, especially to water resources.

As gas drilling expands across Pennsylvania, we should ponder our experience with coal mining. In the name of maximum resource extraction, the natural-gas industry is also using an environmentally risky strategy, called hydrofracturing. It entails drilling deep, horizontal wells into shale formations, after which huge volumes of water laden with chemicals are forced in to break the gas loose.

For more than a century, gas drilling had been taking place in Pennsylvania in relatively shallow, vertical wells. It's this new deep drilling and "fracking" technology that has allowed the industry to greatly increase gas production, profits, and environmental damage.