The performance of covers on tailings piles to limit oxygen migration to the acid generating materials beneath are the topic of an abstract in the latest CIM magazine. In brief, the abstract tells us that measurements of a cover in Quebec since 1996 establish that, except in the upper parts of the sideslopes, the soil of the cover remains moist enough to limit the entry of air to the encapsulated tailings. About five percent of the cover is cover is susceptible to desaturation in dry periods, presumably as a result of downslope migration of the moisture in the cover.

Sadly we cannot access the papers—need to be a CIM member for that. Or see a paper on the same topic from 2003, unless you subscribe to the Canadian Geotechnical Journal. As most TechnoMine readers are not CIM members, and cannot afford the Canadian Geotechnical Journal let me tell you what I did find out on this topic from free sites on the web.

Natural Resources Canada describes the site closure. Similar information about the site and others in Quebec at this link. Hong Kim and Craig Benson have written on the theoretical aspects of the phenomenon—their paper is readily available and worth reading if the topic concerns you. Another good paper that deals more with the practical aspects of acid drainage control including the use of moist covers is my Murphy and Leake of Earth Systems. The most practical and case history oriented is the 1999 Environmental Progress Report from The Mining Association of Canada

One of the delights of trawling the web is to find a superb volume you had not previously seen—here are my picks from this trawl—not much to do with the topic of the CIM paper, but worth your time, nevertheless: