Strip mining is back in the news. The coal industry claims that Americans need the coal for energy, and strip mining is safer than sending miners underground, but at what cost?

Strip Mining – a Definition

One third of America’s coal is mined in the Appalachia using the strip mining technique called Mountain Top Removal which literallymeans the actual removal of the mountain top.The coal is found in the mountain stacked up in layers similar to the frosting in cake and mining operations are set up to remove the coal as effectively and as cheaply as possible.It used to be that mining operations dug tunnels into the mountain and retrieved the coal that way, but with the demands for energy and coal growing it became necessary to find quicker and cheaper ways to obtain the coal. In strip mining, the land is first bulldozed and dynamited to expose the bedrock and coal. Using some of the heaviest and biggest equipment that run on diesel, the top layer (called the overburden) is hauled away and is deposited into the valleys or put back onto the mountain when the operation ends. This effectively exposes the coal, which is mined and hauled away.

Environmental Impact – Water Resources

• The waste sludge from coal mining is a toxic brew of mercury, diesel and other chemicals that are placed into unlined slurry dams, which in turn seeps into the groundwater and eventually finds it way into the drinking water supply. Overburden placed in valleys increase metal burden of the water or in some cases completely covering up the stream.

Environmental Impact- Air Quality

Strip mining affects the air quality in different ways. When all the vegetation is removed the ground is exposed the elements, causing windborne particulates. These naturally occurring particulates like arsenic and lead are harmless when in the ground but when airborne they can cause ailments that affect the respiratory tract when inhaled or a group of other adverse health effects when absorbed through the skin or ingested. The diesel engines of the onsite heavy duty equipment also release toxic particulate matter and toxic gases.

Environmental Impact – Ecology

The increase in soil erosion and metal loading affects the native aquatic life leaving behind fewer species. Ecosystems are truncated by the areas of bare ground caused by the abandoned mines. Despite the federal laws and regulations like Resource Conservation and Recovery Act (RCRA), Comprehensive Environment Response, Compensation and Liability Act (CERCLA) and the Surface Mining and Control Act (SMCA) which are geared to reclaim the savaged ground, restoring the land is near impossible. Re-vegetation is difficult as trees almost always fail to grow leaving mountain tops that have been hydro-seeded. These new ecosystems support only a limited amount of wildlife.

THE ENVIRONMENTAL SCIENCE OF SURFACE MINING

By Alecia M. Spooner

The environmental damage caused by surface mining is related to the large amount of surface material that humans remove during mining operations. The environmental effects of surface mining include

• Habitat destruction
• Soil erosion
• Air pollution from dust particulates
• Pollution (especially from sediments)

All surface mining techniques negatively affect the environment, though some methods are more damaging than others.

STRIP MINING

Strip mining, as the name describes, is a process of removing rock and soil in strips to get to the valuable mineral ores below. After miners extract the resources, they put back the leftover rock and soil, called mining spoilsor tailings, to fill in the hole.

One way to replace tailings is to simply dump them; luckily, U.S. regulations require mining companies to replace tailings in a way that restores the landscape (and ecosystem) more closely to its pre-mined state, even though doing so is often expensive and difficult. When tailings aren’t restored properly, they’re often left in valleys where they cause flooding and disrupt watershed ecosystems with water pollution and increased sediments.

MOUNTAINTOP REMOVAL MINING

Mountaintop removal mining is similar to the strip mining approach in the preceding section but on a much larger scale. This technique removes large amounts of rock and soil — whole mountaintops — to access the resources buried deep inside the mountain.

The mountaintop material is left in surrounding areas of lower elevation, such as nearby river and stream valleys, where it reshapes the landscape, pollutes water, and disrupts ecosystems. The figure illustrates how mountaintop removal mining dramatically changes a mountainous landscape

Credit: Photograph by Getty Images/Pete Mcbride

PIT MINING

Sometimes valuable geologic resources appear at the surface of the Earth but extend deeper into the Earth — sort of a tip-of-the-iceberg kind of thing. In this situation, pit mining (also called open-pit mining) is an option. Pit mining involves digging a large hole to gather rocks and minerals from the Earth’s crust.

Pit mines extend both into the ground and across the surface and are some of the largest mine operations in the world. Like other surface mining operations that remove materials, pit mining operations scar the landscape, destroy habitat, and pollute the air with dust and particulates.

PLACER MINING

Placer mining is a way of obtaining mineral and metal resources from loose river sediments. The water helps sift the valuable resources (such as gemstones or gold) from the sand, mud, and gravel in the riverbed. Placer mining occurs on a much smaller scale than other methods of surface mining.

Whereas other methods go straight to the source of the valuable material, the sought-after materials in placer mining have already been removed from their source by natural processes of erosion and weathering and have been carried downstream. Due to the smaller scale of placer mining, it does less damage to the surrounding environment compared to other methods of surface mining, though it can still disrupt river ecosystems with pollution and sediments.

In some places, such as the Yukon Territory in Canada where placer mining is common, miners make an effort to maintain the water quality by periodically testing for pollution and sediment overload. In some areas, miners have even developed placer mining systems that recycle the water used to sift gold so that polluted water isn’t discharged back into the environment.