OTTAWA – At the behest of the Mine Environment Neutral Drainage (MEND) program, CanmetMINING conducted a survey of mine drainage treatment and sludge management practices at more than 100 sites around the world. They contacted a wide variety of mineral producers and scoured technical papers, company press releases, website information and public documents.
Canmet investigated the site background and history, mine drainage characteristics, type of treatment and reagents used, treatment issues, sludge composition, sludge management practices, and other issues. Most sites expect to treat mine drainage, particularly if it is acidic, in perpetuity. Therefore, the choice of treatment is important both for reasons of cost and of environmental concerns.
Some basic trends were uncovered. About 30% of sites control their influent flow through water management. Active treatment processes were prevalent with chemical application more common than the use of membranes or biological means. Of the sites, about half used basic treatment and half use high density sludge (HDS) processes.
The average cost to treat 1 m3 of mine drainage was $1.54. The average cost of a treatment system was $7.5 million, although the range was wide – from $20,000 to $42 million.
The results have been assembled in MEND Report 3.43.1 available as a free PDF download by clicking here.