WHERE AMD CAN OCCUR
Pyrite is a mineral that is also known as “Fool’s Gold”. Pyrite glitters like a thousand tiny mirrors and is found in the ground with coal. Deep mining, surface mining and spoil and refuse piles expose pyrite, which was once buried in the ground, to air and water. This causes a series of chemical reactions which produces the mine drainage. (See Formation of AMD ) The word “abandoned” is used because much of the Abandoned Mine Drainage (AMD) is caused by mining that occurred before laws were written to protect the water and land. When the mining companies had removed all of the coal that they wanted they simply “abandoned” the mining operation and left the area without any concern of what it looked like or what dangers there were. Therefore, many of these abandoned sites have highwalls, steep spoil piles and open shafts.
It should also be noted that clay was mined heavily in Clearfield County. This causes the same problems as coal mining and can produce more severely polluted water.
Anyone interested in more detailed information should visit http://www.amrclearinghouse.org/.
It should also be noted that clay was mined heavily in Clearfield County. This causes the same problems as coal mining and can produce more severely polluted water.
Anyone interested in more detailed information should visit http://www.amrclearinghouse.org/.
Deep mines were the most common way to take out coal and clay when mining first began. To get the coal, tunnels were dug into the coal seams. The roofs of the tunnels were supported by wooden timbers. Since these mines were underground, airholes or boreholes were dug so air could reach the miners. Over time these tunnels filled up with water and caused the timbers to rot and collapse. The water then comes in contact with the pyrite that is still in the mine and becomes contaminated. Underground pressure pushes the water out at the easiest place to exit. In many cases at a deep mine discharge a person can still see the opening of the mine.
Surface mining or strip mining is the method most used today. The layers of rocks and soil are taken off or “stripped off” by huge machines until the coal is found. This forms dangerous highwalls which can be 100 or more feet high. Today’s mining laws require that highwalls are backfilled and graded so that the land looks as close as possible to what it did before the mining. Before these laws were passed, highwalls were left when the mining was completed. This has left some dangerous conditions in Clearfield County, especially to hunters, hikers, and ATV riders. A number of people are killed each year when they or the ATV they are riding on, falls into one of these pits. Also some pits fill with water that looks like great swimming holes. There are many unseen dangers in these areas. People die from jumping in and hitting an unseen rock or by becoming overwhelmed by the cold temperatures of the water and drowning.
Coal refuse piles or spoil piles are big hills of waste rock from mining. Many times they are formed by material that surrounded the coal but had no value. It was brought out, separated from the coal, and dumped in huge piles, often near streams. Unfortunately, this leftover material is also full of the pyrite that surrounded the coal. Therefore when water flows through the pile it reacts with pyrite forming AMD. Today, due to newer technologies, some material from coal refuse piles is being used as a fuel source to generate electricity.