According to pages 100-101 of the Oil and Gas Operator’s Manual, a region may be determined to be unsuitable for mining if the mining operation will:
- be incompatible with existing State or local land use plans or programs;
- affect fragile or historic lands in which such operations could result in significant
damage to important historic, cultural, scientific and esthetic values and natural
- affect renewable resource lands in which such operations could result in a
substantial loss or reduction of long-range productivity of water supply or of
food or fiber products, and such lands to include aquifers and aquifer recharge
- affect natural hazard lands in which such operations could substantially
endanger life and property, such lands to include areas subject to frequent
flooding and areas of unstable geology.
These seem like worthy goals. So if these areas are unsuitable for coal mining, why is it OK to put gas wells there?
Surface coal mine. Source: http://en.wikipedia.org/wiki/File:Coal_mine_Wyoming.jpg
Granted, drilling a well is not quite the same impact as a surface mining operation, but to protect an area from one mode of mineral extraction and not the other seems inconsistent. After all, many of the problems with coal are still relevant for gas drilling, since the drilling operator must go through the coal seam to get to the gas. The pyrite associated with the coal is still exposed to air, meaning that the drilling mud and drill cuttings probably contain sulfuric acid, the key component of acid mine drainage (AMD).
And it’s not just the drill cuttings that could be a source of problems…it could be the well bore itself. Consider the Hughes Bore Hole, which, according to Wikipedia was drilled in the 1920’s to drain underground mines in the area, then capped in the 1950’s. So what’s the big deal? In the 1970’s, pressure built up and the hole burst open, and has been spewing about 800 gallons per minute of acid mine drainage ever since.
Hughes Bore Hole releasing acid mine drainage. Source: http://en.wikipedia.org/wiki/File:Hughe%27s_Bore_Hole_071.jpg
Could drilling a gas well in the wrong place have the same effect?
Maybe to be safe we ought not drill in areas where geologists have determined that AMD could exist. That wouldn’t affect that many wells, would it?
Oh. Well then let’s hope the well casing experts don’t have any bad days.
[Note: if you want to watch a video of Hughes Bore Hole and don’t mind salty language, click the Youtube link on the “Hughes Well Bore” link above.]