The life of a mine varies wildly. It could be shuttered after 6 months due to a swift decline in market prices for metals. That same site might be reopened 10 years later when a rise in prices makes the site economically viable again. A mine might operate for 20 years with little interruption, but over the course of those years change three times the type of valuable ore it processes. Ownership of the site can transfer multiple times. The development of new extraction technologies might cause some long-closed facilities to be reopened so that ore can be further exploited.
Whatever occurs during the active phase of a mine’s life, the need for responsible closure is always present. Mining activities involve signifi cant disturbance of soils. Dangerous chemicals are used. Environmental threats will remain after operations cease.
A number of measures will be used to treat and clean sediments on site in closure and a number of potentially harmful materials will be buried. Many sites strive to return similar vegetation to the area that existed there prior to the mine’s development.
One of the most effective ways to improve the long-term safety of the site is to isolate what had been the mining zones (e.g., former heap leach or tailings storage facility) by installing a geosynthetic capping system.
Geomembranes, geosynthetic clay liners, geotextiles, and geocomposite drainage materials are used to cover, encapsulate, and cleanly isolate contaminated soils. These systems eliminate infi ltration of precipitation, prevent polluted runoff, allow clean soil to be installed on top to support healthy vegetation re-establishment, and much more.
NAUE Solutions for mine closure
Carbofol® high-density polyethylene (HDPE) geomembranes feature exceptional chemical, biological, and stress crack resistance. Their long service lives in buried installations makes them an ideal impermeable barrier for isolating contaminated soils, old tailings, and other environmental legacy concerns in mining.
Bentofix® GCLs provide efficient, long-term lining performance and strong environmental protection in capping applications. The polymeric coating on the Bentofix® X series provides additional protection against desiccation and root encroachment as well as enhanced gas barrier characteristics.
Secutex® geotextiles provide long-term, robust protection of liner system materials, encapsulation and separation of soils, and filter stability for efficient drainage within closure designs.
Secudrain® is a multifunctional composite material (geotextile and drainage core) that provides filtration, protection, and drainage for gas and water venting in closure systems.
Secumat® erosion control mats have a synthetic matrix that prevents the sliding and washing out of soil and cover layers while facilitating rapid vegetation growth.