The mining industry –which has become a major user of geosynthetic materials – recognises the value of using geosynthetic products for environmental protection, says geosynthetic products manufacturer and supplier Fibertex South Africa (SA) geotechnical engineer Johnny Oriokot.
Therefore, geosynthetics experts at Fibertex SA work closely with mine engineers throughout Africa to provide critical solutions for mine water projects that reduce environmental threats and enhance safety on mines.
Oriokot explains that typical applications for geosynthetics include mine tailings facilities, heap leach pads and water retention ponds. Geosynthetics are also used for mine closures, as well as for access roads and other geotechnical structures.
Oriokot adds that geotextiles have advantages in installations where the cost of failure may be extreme, both in financial and environmental terms.
“Fibertex’s highly UV-stabilised, 100%-virgin polypropylene (PP) geotextiles and geosynthetic solutions take the uncertainty and risk out of the design of crucial applications, like landfills, dams and tailings dams.”
Virgin PP offers a high level of chemical stability under a wide pH range and for this reason, Fibertex geotextiles are particularly well-suited for installation in areas where the textile may be in contact with alkaline conditions, for example, in certain types of slimes dams and waste sites.
Fibertex geotextiles have important functions – the company’s products can be used for separation, filtration, drainage, protection and reinforcement.
“It is critical that mine tailings facilities are isolated to prevent long-term environmental damage,” Oriokot says.
“The Fibertex team has been involved in several tailings management projects, including the installation of geosynthetic products for rehabilitation at a chrome smelter in the North West province.
“In the first phase of this project, Fibertex geocells, silt fence, biodegradable geojute and geobags were used for erosion control and stabilisation of the tailings storage facility.”
Fibertex Greencells are highly efficient cellular containment systems (geocells) used to stabilise structures like embankments, river profiles, sand dunes, base courses and drainage canals.
Greencells are manufactured from alternatively stitched UV-stabilised, coated geotextile strips to form a continuous honeycomb-type square cellular mat. The geocell is then filled with concrete, or a variety of natural materials, like earth and gravel.
The walls of the material are impermeable and can be perforated on request, with one side textured and the other side smooth. The lightweight, durable material has a high tensile strength of 25 kNm. It is resistant to alkaline conditions and is easy to install.
Geocells are beneficial in the mining industry as they provide a three-dimensional stabilisation structure, constraining the infill material from lateral movements, which, in the slopes of tailings facilities, prevents erosion of surface material. In addition, geocells can be incorporated in access roads, as they ensure the use of the in situ material, without excessive development of rutting, he adds.
Fibertex Polytex silt fence geotextiles allow for water to pass through the fabric, restricting the loss of important top soil particles. This material is used to retain sand and silt particles and protects lakes and streams from harmful silt build-up.
Oriokot notes that Fibertex silt fences prevent the loss of material from tailings that would eventually clog up the drainage piping systems and channels. In addition, excessive loss of material from the slopes could potentially result in structural damage and collapse of the structure.
Biodegradable geojute is used to aid in rehabilitation of old mining tailings structures and the re-vegetation of slopes that are susceptible to excessive erosion.
“In this project Fibertex geobags, manufactured from UV-stabilised woven PP geotextile materials, filled with the tailings, were incorporated alongside the access steps of the storage facility to prevent scour erosion of the structures. The function of geobags is similar to silt fences, in that they hold solid particles back, thereby preventing erosion,” he says.
“This environment-friendly system has advantages over conventional methods, which are often unaffordable to mining authorities and contractors with limited budgets. Benefits of using geobags include ease of operation, efficient retention of solids, compliance with environmental regulations and cost optimisation.”Creamer Media Deputy Editor: Features