EGEE 101
Energy and the Environment

Acid Mine Drainage

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Acid does not all come from the sky! Pennsylvania has about 3,000 miles of polluted streams, creeks (I am not sure what the difference between creeks and streams are, we don't have "creeks" in the UK!). The culprit is not thousands of miles away, it is much closer to home: abandoned coal mines & culm piles. Recall when we discussed coal mining activities that the pyrite in the coal is uncovered and dissolves in the water, migrating through the abandoned coal mine. When the mines are abandoned, the pumps are taken out and the mines often flood with acidic water that can flow into the streams and pollute the water table. The Culm piles also expose the pyrite to the elements (wind, rain, hail, snow, etc.) and so they too contribute to the acidification of the local waterways. Pyrite is fools' gold and contains iron and sulfur.

(left) yellowish stream flowing out of an old mine entrance (right) discolored stream through the woods.
On the left, an old mine entrance, or perhaps a ventilation entrance, which long ago flooded, leaving visual evidence of acid mine drainage (AMD) here that adds to an already high pH level for rainwater of the North East. On the right, a more picturesque stream (or sulfur creek), in Northeastern PA, discolored because of the Iron Hydroxide (orange color) deposits. The iron comes from the pyrite, and the sulfur will be dissolved, forming sulphuric acid, which lowers the pH and makes the stream more acidic.
Left: Office of Surface Mining. Right: EPA
A short movie about acid mine drainage.
Click Here for a Transcript of the Acid Mine Drainage video

[Video opens panning down a discolored stream.] Dr. Mathews: This is a beautiful area of the anthracite region. This is one of the many sulfur creeks. It gets that name from its yellow or orange color in nature. This is due to acid mine drainage. What happens is the iron discolors the bed, the stream bed, with this yellow coloration, it is called yellow boy, and it is actually iron hydroxide. Unfortunately, it means that the stream is in very poor health and it is not a good spot to go fishing. It is very sad to see the beautiful areas of this anthracite region devastated in this manner. [Video ends panning the stream.]

Credit: JPM
Anthracite breaker in front of a culm pile.
An old anthracite breaker stands in front
of the culm pile.
Credit: JPM

To the left, an old anthracite breaker stands in front of a culm pile. Recall that this culm can be cleaned and used to fuel fluidized bed combustors. The breaker is where the coal was crushed and sized. The coal which was rejected (because the particle size was too small or the coal obviously contained significant quantities of other rocks) was thrown away on top of the pile. The exposed pyrite in the pile will produce acid mine runoff when it rains.

The effects of AMD on wildlife can be significant, as evidenced by the map below. Look at the distribution of fish on this map, then click on the arrow to see where the major coal deposits are in Pennsylvania. See any connection?