The mining industry uses geomembranes for a variety of waste containment systems. Because they are durable, puncture-resistant, and can withstand harsh environmental conditions, chemical solvents, heavy metals, and even radioactive materials, they are ideal for containing mining processes and byproducts.
Here Are Four Ways Geomembranes Are Used for Waste Containment Systems in the Mining Industry:
1. Liners for Heap Leaching
Heap leaching is the process of extracting metals including gold, silver, copper, and uranium from ore. To do so, the ore is crushed into a pile or “heap” and placed on sloping ground. A leaching solvent, such as acid or cyanide, is then applied to the top of the heap. As the solvent trickles through the pile, it dissolves the metals into it, and the drains them into a collection pond.
The entire process takes place on a heap leaching pad lined with geomembrane material that is at least 1.5mm in thickness. These pads must be able to withstand significant weight, extreme temperatures, and abrasive chemicals. Liners must also be exceedingly puncture-resistant and durable as the process can take between two months and two years to complete.
2. Liners for Waste Rock Dumps
When heap leaching is complete, the non-mineral bearing rock is leftover. Often it has been drilled, blasted, or excavated, and is otherwise considered waste. This rock is dumped in storage facilities known as waste rock dumps. Because it takes one ton of rock to produce only one or two grams of gold, waste rock dumps are some of the most massive structures on the earth—some containing up to one billion cubic meters of material. As you can imagine, these often fill medium-sized valleys.
Because the excavated rock may still contain toxic or radioactive materials, as well as heavy metals such as arsenic, once again, geomembrane liners, are employed. The most commonly used HDPE and PVC liners for this instance are 1.5-2mm and 0.75-1.0mm thickness respectively.
3. Liners for Tailing Containment
When gold, silver, copper, and uranium go through the heap leaching process, they leave behind byproducts known as tailings. These sand-like leftovers can be dangerous if accidentally dispersed. Uranium tailings, for instance, contain 85% of uranium’s total radioactivity—which can prove hazardous or fatal if introduced to waterways or food supplies.
For this reason, tailings are stored in impoundments known as Tailings Storage Facilities (or TSFs) or Tailings Dams. These TSFs are lined with geomembrane material to contain the tailings and their properties without leaching them into neighboring soil or water. High-density polyethylene can also be used as a cover for tailings as they are resistant to acidic and alkaline agents, salt solutions, and microbes, as well as chemical attack.
4. Liners for Settling Ponds
Mining operations that extract coal, copper, gold, diamonds, iron, lead, limestone, nickel, salt, uranium and other precious metals and stones produce wastewater that contains dissolved heavy metal ions. These ions can affect the acid/alkaline balance of receiving waterways if not appropriately treated. For this reason, settling ponds or basins are used to remove impurities and improve the water quality leaving the facility.
Settling ponds work by holding water until suspended solids are settled and then removed. Sometimes chemical treatments are used to hasten the settling process. As with our previously mentioned mining operations, these settling ponds are lined with geomembrane material. This prevents contamination of neighboring waterways.
BTL Liners makes heavyweight reinforced geomembrane liners for the mining industry. They are used for a variety of waste management systems including heap leaching, waste rock dumps, and tailing containment processes. Our secondary containment systems protect food and waterways from toxic, flammable, reactive, corrosive, or combustible mining materials.
Our liners can help you lower cleanup costs and insurance premiums, as well as reduce liability risk and environmental damage. Plus, they are available in flame-resistant material. If you are looking to improve your waste containment systems, give us a call. We’d be happy to provide you with a quote on your mining needs.