Tailings and Mine Waste Conference

Rooting morphology and salinity/pH interactions in monolayer soil covers above copper tailings Milczarek, Michael; Steward, Michael; Word, Wesley; Buchanan, Margaret; Keller, Jason

Abstract

In an effort to understand rooting morphology and the long-term potential for upward migration of solutes from tailings of varying geochemical conditions into evapotranspirative cover systems, test pit investigations were conducted in cover systems of varying thicknesses and age in the Southwestern USA. Study results indicate that rooting density is typically uniform throughout the cover system profile and does not exhibit the exponential decay with depth common in undisturbed reference areas. Root propagation was observed into tailings with pH > 4.5. Increased salinity or decreased pH conditions in the cover system were generally limited to the bottom 15 cm of the cover system, directly above the cover/tailing contact. The extent of upward migration and accumulation of solutes in the cover soils varied depending on the tailing geochemical conditions and the cover system depth. In general, cover soils < 30 cm in depth showed greater salinization than cover soils > 60 cm. Increasing tailing acidity generally resulted in decreased pH and increased EC above the tailing/cover contact; covers above tailings with pH > 4 typically did not show accumulation of solutes. [All papers were considered for technical and language appropriateness by the organizing committee.]

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Attribution-NonCommercial-NoDerivatives 4.0 International