Mining Uses for Geomembranes

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In addition to being universally popular for road construction and pond lining projects alike, geomembranes are essential for the mining industry. Other industries only have a handful of uses for these liners, but mining facilities often have half a dozen or more uses per location. While different purposes may call for slightly different thicknesses or other characteristics, most applications can be solved with a similar kind of material. Find out how to adapt geomembranes to every need in the mining industry for more reliable production and a healthier profit margin.

Bottom Liners for Full Containment

The foundation of any modern mining treatment plant is the bottom liner. Installed below any equipment or ponds designed for processing holding mining materials and waste, this is the primary containment method for preventing spills and losses of valuable products. Using a continuous layer of geomembrane under an entire facility may sound like a major challenge, but it&#;s easier than you think with the right materials. Mining tailing ponds and heap leaching pads definitely require at least one bottom liner layer to prevent contamination. These features may also need secondary layers and leak detection systems, depending on local regulations and the particular material being handled in the system.

Pond Liners

Geomembranes are particularly popular as pond liners, even when the pond in question is holding mining waste rather than fresh water and fish. Ponds are the most popular option for holding large amounts of water and waste in the mining industry. Digging into the ground to support the weight of a large storage area makes more sense than building above ground and spending extra money to reinforce the holding structures. Even if above ground tanks are preferred for holding smaller amounts of the total wastewater for processing, ponds are better for bulk storage and long-term holding.

Heap Leaching Pads

Heap leaching is a widely used technique that efficiently separates valuable minerals and metal ores without much energy use. However, this technique requires a durable liner that can withstand the heavy weight and sharp edges of the heaped material. Since leaching involves the gradual dissolving of desired ores and minerals, this runoff must be captured for later refinement. If the heap is built without a proper leaching pad, the runoff will escape into the environment and waste valuable materials. Leaching processes also involve harsh chemicals such as cyanide to break the minerals and ores loose from the bulk crushed rock material. Make sure to choose a liner that can handle that kind of chemical exposure year after year.

Dams and Secondary Containment Basins

Dams blocking the overflow areas for large ponds and other in-ground structures require careful lining too. For the best results, pond lining materials like geomembranes should flow seamlessly from the main structure over the dam. This ensures a leak-free design that doesn&#;t stretch or bulge at the base of the dam where pressure is the highest. If secondary containment basins are needed for other tanks and storage units, flexible geomembrane liners are generally the easiest choice. Pre-cast and temporary containment methods are both expensive and highly limited. Flexible liners are easily cut and shaped to fit the largest secondary containment structures with a low permeability surface that stops leaks and seepage.

Soil Reinforcement for Slopes and Roads

Mining sites generally require miles of continuous and interconnected roadways and paths to link the various extraction and processing sites. While these roads are generally left unpaved and covered only with gravel, lining them with a geomembrane is often a recommended practice as well. Geomembrane works well as a road base material whether used for temporary or permanent roads. Roads built with a geomembrane layer are less likely to erode or collapse, especially when built on the steep sides of a large strip mine. Slopes prone to erosion are also commonly reinforced with geomembranes or other geotextiles to prevent soil loss and landslides.

Ditch and Canal Liners

Canals and ditches are needed to connect the many tanks and ponds used in the mining refinement stages. These in-ground, open air, water carrying structures offer far more volume and flow capacity than any enclosed pipe. Yet just like ponds and other storage units that make up the mining system, these ditches and canals need proper lining to prevent water loss and evaporation. Flexible liners are essential for filling in the smaller spaces of these parts of the system. To eliminate leaks as much as possible, use the same geomembrane material for the ponds and tanks as you use in the canals and ditches.

Covers and Evaporation Controls

Don&#;t forget about the potential need for covers on top of the process pond or heap leaching pad either. Many mining ponds and tanks are left open to the air in order to let gases escape as they form. However, this can cause either unwanted water gains due to the flow of rainfall into the pond or a high concentration of minerals due to evaporation. Covers made from materials like ArmorCover are ideal for keeping vapors, gases, unwanted water intake and evaporation under control. These flexible liners can be removed and replaced as needed if conditions change between seasons.

With so many uses for a quality geomembrane in the mining industry, it&#;s unsurprising that nearly half of all relevant materials are purchased by these companies. The same tough and flexible liners that work well for primary containment in large ponds also double as secondary containment and ditch liners when used with care. Find the geomembranes you need, including plenty of cover options, here at BTL Liners.

Are you interested in learning more about Geomembrane Pond Liner for Mining? Contact us today to secure an expert consultation!

Which Geomembrane Materials Work Best for Mining Applications?

With so many uses for geomembranes in the mining industry, during both active and closed stages of a project, it&#;s no wonder they&#;re so widely used. However, not all geomembrane products will work for mining applications. Using the wrong material for a hydraulic fracturing brine pond or a heap leaching pad will only result in failures and costly losses. Making the right choice from the start is easier than you might think. Simply choose a polymer based on their characteristics, decide on reinforced and textured features, and consider how you plan to install the liner.

Choosing a Polymer

There are over a dozen different common polymers used for manufacturing geomembranes. These products are further divided into dozens more specific formulations of additives and plasticizers. Start with a general polymer category and then narrow down the options based on product specifications. The materials commonly used for mining geomembranes include:

• High density polyethylene (HDPE). This durable material is widely available, but it&#;s far more prone to cracking under stress than other types of polyethylene. It offers decent chemical resistance and less UV resistance than RPE. Welds are reasonably strong for reliable seams. Unfortunately, this is balanced out by poor puncture resistance and extensive thermal expansion in applications with hot wastewater. This material isn&#;t a great choice for use on its own in a mining project.
• Polyvinyl chloride (PVC). More flexible than HDPE liners, PVC isn&#;t very durable and lacks the chemical resistance necessary for mining use. The material resists wrinkling relatively well due to its flexibility, but it&#;s less durable and offers poor tear resistance in rocky soils. It&#;s also not entirely UV resistant in most formulations and will break down eventually when installed in an exposed setting. High and low temperatures also damage PVC liners, both of which are possible on the mining site. Skip this material for process and storage ponds.
• Chlorosulfonated polyethylene (CSPE). Based on the popular polyethylene polymer, this particular formulation is strongly resistant to certain chemicals like bleach. Few of its particular strengths are needed by the mining industry. With a low tensile strength, it&#;s a particularly poor choice for heap leach pads and similar high weight applications. The stretching force of sediment or ore will cause too many tears and punctures to develop in a CSPE liner. Unless the specific chemical resistance is needed from this liner, avoid it for most mining geomembrane purposes.
• Flexible polypropylene (FPP). Polypropylene is generally used in rigid forms, but it&#;s also available as a flexible liner material. Unfortunately, its weakness against hydrocarbons mixed into the mining waste makes it a bad choice for most natural gas, petroleum, and hydraulic fracturing purposes. It&#;s easy to manufacture in large sizes, but it&#;s harder to find in general and tends to cost more per square foot than other commonly available liner materials. It&#;s generally not a good fit for most mining geomembrane specifications.
• Low density polyethylene (LDPE). For the combination of chemical resistance and flexibility, LDPE is a relatively good choice. Yet it still has some disadvantages that keep it from being the ideal choice for most mining projects. First, this material is even less UV resistant than HDPE geomembrane. It&#;s also less chemical resistant. While the softer material is less likely to wrinkle than stiffer membranes, especially when reinforced, it&#;s not as durable as you need for mining purposes. Rough ores and sediments will quickly wear out a liner made of LDPE alone. LDPE is not an ideal liner when used alone, but it may work well in combination with other geomembranes.
• Reinforced polyethylene (RPE). For the best features of all the above polymers in a single package, look for RPE geomembranes. These mining geomembranes offer the highest grade of both chemical and UV resistance due to the combination of both HDPE and LDPE in a single product. The reinforced design provides strength, wrinkle resistance, conformation to unusual curves, and tear resistance all at once. RPE also works well for covering both active and closed mines. If you&#;re in search of an RPE geomembrane product that can handle the challenges of mining installations, check out our selection at BTL Liners.

Benefits of Reinforced Geomembranes

Reinforced geomembranes are recommended for the mining industry. These liners offer a better lay flat experience, reducing the number of wrinkles formed during installation. Wrinkles that aren&#;t removed, slowly compress over time due to the weight of the water and combined sediment. Ores being processed in ponds are especially heavy and tend to stretch non-reinforced liner products. Reinforced polyethylene (RPE), in particular, is designed to resist stretching and expansion under heavy loads. These liners are also more resistant to freezing damage caused in cold climates, making them a good choice for mines located in the higher and lower latitudes of the world.

Surface Texture and Why It Matters

The surface texture of a particular geomembrane product also determines how well it will bond with the soil above and below it. Smooth membranes may spread easily, but they don&#;t offer as much grip as products with some kind of texture on the surface. Interfaces that create more friction help prevent movement of the liner, especially when using steeper slopes around the sides of the pond or catchment basin. Textured liners also help control erosion by slowing the flow of water over the surface when there&#;s a runoff issue. If you&#;re installing any exposed liners, you&#;ll definitely want a textured product to keep surrounding material from shifting onto the surface.

Weight, Durability, and Stiffness

Consider how weight, stiffness, and durability work together to control the functionality of a particular mining geomembrane. Thicker geomembranes tend to be more durable, but they&#;re also generally stiffer and heavier as well. Stiff liners are at greater risk for cracking, especially when wrinkled. It&#;s also harder to get the material to fit smoothly into corners and form good seams in uneven areas. Thinner materials are less stiff and therefore more flexible, in addition to offering a lower weight. Low weight materials are easier to install, as are flexible products. If you choose a material like RPE that is durable and strong despite being thin and flexible, you can enjoy the best of all three factors in one package.

Features Essential for Mining Use

Geomembranes need more than just flexibility and chemical resistance to qualify for mining use. Ease of installation and seam sealing determines a large proportion of the total cost. If you choose a less flexible and heavier material that is hard to spread out and seal together, it&#;ll cost more in the long run than an easier to handle material. Make sure you&#;re choosing a vapor blocking barrier as well if that&#;s specified in the project plans. Don&#;t forget about wear and tear resistance if you plan to use any heavy equipment to scrape or empty the processing ponds of valuable sediments and ores at the end of the treatment cycle.

Exposed vs Buried Installation

Only geomembranes explicitly labeled for exposed use should be installed that way. Using liners designed for buried and covered installation in an exposed setting will only lead to rapid failure. UV exposure is detrimental to liners that aren&#;t designed to withstand it on a daily basis. Even short-term exposure to a buried liner due to shifting ballast can lead to leaks. Check on ballast regularly to keep low spots well covered so UV damage can&#;t occur.

Don&#;t become overwhelmed by the options available today for mining geomembranes. If you need help making your selections for various parts of your project, contact us here at BTL Liners. Our team will advise you on product choices based on each section of treatment or processing steps. No matter what kind of ponds and channels you need for your mine, we can help you find the right liner.

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