What do Tesla, Apple, and Ford have in common? They all rely on mines that produce metals like lithium, which drives our technology-hungry world. Now, more than ever, mining operations must run efficiently to meet increasing demand. Equally as important is supporting positive public beliefs on mining. Environmental reports from end-users aside, mining operators must incorporate high safety standards to ensure a prosperous future because public opinion can make or break industries.
Fortunately, there are ways to use products like geosynthetics to improve safety in mining applications. In this article, we will briefly describe geosynthetics, explain how geosynthetics can improve safety factors in mining applications, and explore ways to help improve environmental safety.
What are geosynthetics?
Mining operations rely on evaporation ponds, heap leach pads, tailings storage, process ponds, and more. An effective mining solution can positively affect these operating segments to protect the project’s long-term investments and minimize ecological impact. Geosynthetics are products made with polymers and used for terrain stabilization. Often, geosynthetics manufacturers incorporate multiple products into a solution to manage various functions such as separation, reinforcement, filtration, drainage, and barrier (low permeability).
Nonwoven geotextiles, a slope stabilization fabric, can contribute toward separation and filtration when covering tailing impoundments, while geogrids offer stabilization and reinforcement for new nearby roadways. When combined with vertical drains, installers can safely and sustainably reclaim tailing ponds (1). Other products include liners with built-in texturing that support slope stability, essential for improving safety factors.
At the heart of each geosynthetic product is the polymer. One of the best polymer options for liners in mining applications is high-density polyethylene (HDPE), which features exceptional resistance to chemicals, stress cracks, tears, punctures, and ultraviolet (UV) radiation. Engineers may prefer a linear low-density polyethylene (LLDPE) liner for applications that require improved elongation at break and tensile properties.
How can geosynthetics improve factors of safety?
Engineers use safety factors to reduce risk when constructing heap leach pads or other mining constructs, and safety factors create a margin between rated limits and failure points. For example, most mines rely on slopes to help improve mining efficiency by enabling taller builds or introducing gravity to create flow into trenches or holding ponds. By using a liner or slope stabilization fabric with improved shear performance, installers can incorporate improved factors of slope stability to reduce the risk of failure (2).
These liners function by adding texturing that increase the interface shear strengths between the membrane and the subgrade and/or other liner material. The texture digs into geotextile / slope stabilization fabric, soil, or geocomposite to prevent sliding and other movements. Geosynthetic products, like geogrids, can also help reinforce other soil structures like berms, embankments, and crusher walls.
How do geosynthetics improve environmental safety?
Mining operations use acids and other toxic chemicals in various processes. In heap leaching, the byproduct (pregnant solution) requires containment to increase recoveries and prevent the solution from seeping into the soil or local waterways. Installers can use low-permeability products such as geosynthetic clay liners (GCL) or geomembranes to avoid environmental contamination. These liners can help create safer pregnant solution trenches and other onsite containment spaces. A mine’s service life is often dynamic, but one constant is the eventual need for closure. Engineers can minimize the environmental impact of post-mining operations by isolating mining zones with a capping system. For example, tailings or heap leach closures can reduce acid rock drainage from entering the groundwater. Most closure solutions typically incorporate multiple products for padding, protection, low permeability, drainage, and stability. However, combining these layers into one geosynthetic solution can improve installation time and reliability, and AGRU produces such solutions.
- 1. F. Ewart, G. Heerton, and M. Lersow, “Using Geosynthetics for Safety Mine Closure, Closure of Mining and Milling Residues and for Groundwater Protection.” Conference: 10th IMWA Congress, 02.-05. (2008). Accessed online 20 September 2021. https://bit.ly/3u1DFpp.
- 2. Kelsey, “The Use of Geosynthetics in Mining Works.” Geosynthetica. (2020). Accessed online 20 September 2021. https://bit.ly/2XyFRJp.