Mining is necessary to extract the essential ores, oil, and coal we rely on every day. However, it does produce a large volume of potentially hazardous material that requires special care. While the overburden material excavated from above a valuable seam of ore or oil isn’t the most hazardous material from the mine, it still requires containment to prevent environmental damage. Failing to keep overburden contained and in place can result in losses of important reclamation material as well. Consider these risks to the surrounding environment before settling for a less reliable liner or compromising on containment measures like berms.
Topsoil Stripping
Almost every site that qualifies for surface mining techniques has a thick layer of topsoil and vegetation to start with. Focusing too much on the overburden material that lies below this initial topsoil layer can leave it wasted in the rush to get started. Keeping topsoil intact and separated from other overburden materials is essential to maintain the organic material necessary for rapid site recovery. While overburden is a good fill material to restore the height of the surface after mining, it is not always the best material to leave exposed. It can erode away easily and is often too harsh to let plants establish directly. Yet, topsoil can also be lost if it is simply dumped back on the surface. Applying topsoil at the right stage in remediation is only possible if it is separated from the overburden from the start during containment.
Wind Scouring and Dust Storms
Due to the removal of the vegetation and even the surface of the ground itself, surface mining operations are at specific risk for wind scouring. Even just the loose material on the active surface of a mine and its roads can create serious dust problems for the site. Add in the material stored in heaps around the site and there’s a compounding chance for hazardous dust storms to begin. Since overburden dust often contains heavy metals, toxic compounds, and other problems, it is best to contain and keep it from leaving the site or even entering the air whenever possible. Watering the heaps of overburden material is one of the most effective ways to control dust, but this creates leachate that must be contained as well. Using liners and covers from BTL Liners can give you complete control over the loss of both moisture and dust from an overburden pile.
Acidification
Overburden material tends to be highly acidic. In fact, some coal mining materials often measure a mere 2 or 3 on the pH scale. This kind of extreme measurement makes it hard to establish vegetation. Yet, covering the site with vegetation as rapidly as possible is the exact thing necessary to prevent erosion and wind scouring alike. Letting the material escape from the overburden pile or wash away into the nearby streams and waterways also risks soil and water acidification. Acidification of the natural aquatic habitats around the mining site can result in high remediation expenses and long-term effects. Acidification of the site can be kept under control by lining the storage areas and keeping overburden material buried under a cap of more pH balanced material.
Leaching and Runoff
Leaching through the piled overburden material is one of the main handling concerns. While overburden is not the most hazardous material produced by the mining process, it still has its own risks. Rainwater that leaks through the material tends to dissolve the minerals, heavy metals, and salts found within it. Sand, clay, and gravel overburden can be full of a dozen different potentially toxic compounds. If it remains mixed within the dry material, it is easy enough to contain in either a waste facility or the mining site itself during remediation. However, the size of the piles used to store overburden makes it challenging to keep the material perfectly dry with covers. Instead, most facility owners choose to contain the leachate and dispose of it safely underground. A durable and impermeable liner from BTL Liners is the first step in containing the runoff without putting the environment at risk.
Erosion and Landslides
All forms of mining are at risk for erosion and landslides, but the greater area of a surface mining operation inherently puts it at greater risk than pits or deep mines. Even the slightest amount of slope in the surface mine can trigger large scale landslides that put equipment and mine employees at risk. The removal methods chosen for excavating the overburden largely determine the erosion and landslide risk within the mining site. Yet, only proper storage and containment techniques will prevent it from collapsing after its removed. Steep-sided, tall piles are commonly used for storing overburden, but these structures are prone to sliding and are harder to line for leachate control due to their total weight. Smaller piles, that are built carefully with multiple flattened lifts of material, are easier to stabilize and control to prevent both landslides and erosion over the course of storage.
Get a new perspective on dealing with these challenges by exploring the containment and stabilization options offered by BTL Liners products. We offer both liners and covers to ensure that even the riskiest forms of overburden are well-protected. Don’t let environmental damage or other issues interfere with the operation of a surface mining facility by building secure overburden pads with our help.
