Professor Column: Possible consequences of the extractive industry

Resource extraction in Appalachia has taken several forms over the years. Here, I will focus on the lasting environmental impacts of coal mining and the emerging impacts of shale gas extraction.

Coal was mined for many years in Appalachian Ohio, leading economic development and great environmental impact. Coal was formed from buried plant and animal matter over a long period of time and both high temperatures and pressures underground. The atmosphere contained far less oxygen than ours does today. Coal and the rocks directly above and below it often contain both metals and sulfur, often in the form of pyrite or iron sulfide. When we mine coal, we expose the coal and the associated metals and sulfur to the higher level of oxygen in our atmosphere. In contact with both oxygen and water, the minerals release metals — particularly iron, aluminum and manganese, and sulfur — in the form of sulfuric acid. The resulting metal rich, acidic water is called acid mine drainage.

Acid mine drainage discharging from abandoned underground mines, abandoned surface mines or piles of mining waste (called gob piles or slag heaps) pollutes streams. The acid mine drainage acidifies streams and kills most aquatic life, including fish and bugs. Hundreds of miles of streams in Appalachian Ohio are polluted by acid mine drainage. Over the past decade, local watershed groups and the Ohio Department of Natural Resources have invested millions of dollars into treatment and have restored 46 miles of stream to good ecological standards. The slow progress and high cost of acid mine drainage treatment demonstrates the lasting legacy that a relatively short-term extractive industry can have.

The exploitation of natural gas trapped in deep shale formations is the newest round of resource exploitation hitting Appalachia. This exploitation is now possible due to advances in drilling technology; companies can now drill a horizontal lateral from a vertical bore very accurately using horizontal drilling technology. This so called ‘gas boom’ is fueled by large quantities of water, silica sand and chemicals. A horizontal shale well is first drilled over a mile deep and often up to a mile horizontally into the shale layer. The well is cased with steel that is concreted to the rock to try to protect groundwater supplies. The drilling process produces a large amount of drill cuttings that must be landfilled.

After the well is drilled and cased, the production casing (the layer of steel that is placed along the entire well bore) is perforated using charges deep underground. The fracturing fluid, a mix of water, silica sand and various chemicals, is then pumped under high pressure into the well bore to hydraulically fracture the shale to allow the gas to flow from the shale layer. The process is an industrial process that brings many risks with it. Each pad is about 5 acres of land and are placed about one half mile apart, about eight well bores are drilled on each well pad. Each well uses approximately 5 to 10 million gallons of hydraulic fracturing fluid made up mostly of water, usually made up of fresh surface water or of water from city supplies. Of this water, sand and chemical mix, about 25-40 percent of the water returns to the surface during production; the rest is removed from the surface fresh water cycle indefinitely. The produced fluid may be reused to drill more wells, applied to roads for dust and ice control or re-injected deep underground.

Ohio is the main recipient of this wastewater from Pennsylvania and West Virginia. Beyond the infrastructure damage caused by the industry, some of the key risks to water include large amounts of extraction to make up fracturing fluid, cracked or poorly cemented casings allowing for fluid migration, leaking holding ponds for produced fracturing fluid and truck crashes and spills. Given the time and money put into cleaning up streams in Southeast Ohio, shale gas exploitation poses huge risks to Appalachian water resources and threatens the future environmental quality of the region.

Natalie Kruse is an Assistant Professor of Environmental Studies in the Voinovich School of Leadership and Public Affairs. Kruse holds a Ph.D. in Civil Engineering and Geosciences from Newcastle University, and a B.C. in Civil Engineering with a minor in Geological Sciences from Ohio University. A winner of the Marshall Scholarship, Kruse won the Best Paper award from Mine Water and the Environment in 2009. She also won the Barry M. Goldwater Scholarship and the Morris K. Udall Scholarship. 

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2 comments
  1. Bethany said:

    Thanks for this informative post! Very well-written. I look forward to future posts like this!

    • Austin said:

      Bethany, check back every Wednesday for professor columns. Four professors have already shared their expertise with us on various issues as well. Check out the rest of the environmental blog for more

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