The daily mining rates, scale of single-site operations, and costs associated with mining increase every year. Advances in extraction technologies have greatly increased recovery rates from ore bodies. Mine designs previously thought to be too big to be possible are achieved every year or two so that an average mine today is signifi cantly larger than an average mine just 10 years ago.
To construct on this scale, which is often necessitated by marketplace price points and competition for investor support, requires substantial engineering to make mines economically feasible and environmentally sound.
A large amount of the world’s annual production of geomembranes is used by the mining industry, and for good reason. Heap leaching has grown substantially as a technique for extracting valuable material from ore. Ore heaps of 200 m are being constructed. Mountaintop and “valley leach” designs are implemented. Geosynthetic lining systems contain the pregnant solution so that it is not lost in seepage into soils and does not flow into local waterways. Gold, copper, nickel, uranium, and even rare earths are being heap leached. Geosynthetics contain the valuable reserves and isolate the waste (the tailings), thus providing economic and environmental advantages to the site.
“Raincoat” liners keep stormwater out of ore heaps so that the pregnant solution is not diluted. Processing is more efficient this way. Also, geosynthetic lining systems protect water resources on site. With water costs in some regions having increased by 300% in the past fi ve years, conserving water on remote mining operations significantly reduces expenses.
Containment isn’t the only solution needed to keep mining operations competitive and viable. A vast range of geotechnical works is required for operational performance and environmental security. Geogrid reinforcement stabilises berms, embankments, crusher walls, and other soil structures. They support access roads so that 100 ton payloads can pass daily for years on site without costly roadway failures. (A mine can lose millions of dollars, USD, per day if an access road fails.) Geotextiles provide separation of granular layers, fi lter stability in geotechnical constructions, and protection of other geosynthetics.
In combination, these materials improve the recovery of valuable materials, isolate contaminated waste, keep sites open, and make closure a more effi cient and less costly endeavour.