It’s not enough to simply specify certain mining geomembranes during the original construction of a mine. These materials should also play a role in the end of the mine’s lifespan. Reclamation allows for the mine to become a natural and useful site again while preventing waste products from contaminating the surrounding environment. Naturally, geomembranes are a great choice for this challenge. The same mining geomembranes used for setting up bottom liners tend to work well for capping and sealing reclaimed mines from the top as well. Learn a few new tips on how geomembranes are best used in mine reclamation projects.
Primary Containment with Buried Liners
The buried liners used as bottom layers or catchment basins form the first layer of protection against contamination. Without an impermeable layer below the soil or sand, mining storage ponds tend to cause extensive environmental damage over time. Remediation takes many times more resources when there’s no containment designed from the beginning. If you’re working on an older system that isn’t ready for shut down and reclamation yet, consider installing liners now regardless. Adding buried liners at any stage prevents further damage from occurring as the ponds and processing basins age.
Reliable Capping Performance
Geomembranes do more than just keep water from soaking into the ground below the mining deposit or storage pond. In addition to controlling water exchange, capping membranes trap vapors that might escape through layers of soil or natural clay liners. This means that many mining reclamation projects can use the same flexible RPE liners for the bottom layer as for the cap on top. Pairing the same polymers on the top and bottom provides a stronger seal between the two layers, reducing leaks of both liquids and gases. Even if you plan to cap your mine reclamation project with other materials, add a geomembrane layer as well for optimal performance.
Infiltration Control from Above and Below
As mentioned in the previous two sections, geomembranes assist in the mine reclamation process by controlling water infiltration from both below and above. Water rising from a high water table can enter the holding ponds or buried deposits and cause runoff issues. A bottom liner prevents that from becoming an issue, but only if you choose an impermeable material. The same is true when controlling dilution and flooding caused by rainfall entering from the top. Capping with an impermeable geomembrane liner is the best way to ensure rainwater doesn’t drain through the mine’s buried material and cause a runoff problem.
Planning for Re-vegetation
Re-vegetation is one of the most powerful methods for reclaiming a damaged or degraded mining site. However, don’t assume that planting grass or trees is incompatible in some way with using geomembranes. It’s perfectly possible to design capping systems that use both living and synthetic materials in combination for a useful and long-lasting reclamation project. Planted mines recover faster and function better as parks or housing developments than bare areas covered only with soil and geomembranes. You may need to bury the liner deeper to compensate for root growth, but careful plant selection also allows you to work around relatively shallow layers of soil cover.
Combining Layers of Geosynthetics
Most mine reclamation projects involve more than one type of geosynthetic in addition to geomembranes. While geomembranes are impermeable and perfect for controlling water flow, they’re not right for every capping or sealing purpose. Geosynthetic clay liners are commonly combined with these systems to reinforce loose soil above and below the mine deposits. Geotextiles are also regularly added to loose or steep mine sides to prevent collapse after an area is filled or covered. Non-woven matted or extruded geofabrics are also commonly used as underlayment to protect geomembranes from rough soil or the formation of small voids in loose dirt.
Importance of Seam Control
The seams in the liner under a mine reclamation area come under extra amounts of stress as fill material is introduced into old mine pits and storage ponds. If the material is added to a weakened liner, the bottom layers of the material can rip and cause leaks into the soil below. In order to protect the soil and the water table below the surface, it’s necessary to protect the original liners sealing the ponds or pits. Building strong seams from the beginning with the selection of the right geomembrane material is essential to successful mine reclamation years later. Ordering custom fabricated liners is one of the best ways to prevent stress leaks from developing over time.
Get the most from your mine reclamation project by choosing the right mining geomembranes for each stage. Whether you need to add new bottom liners or simply need to finish a cap to start building over the surface, we have everything you need here at BTL Liners.
