The formation and potential importance of cemented layers in inactive sulfide mine tailings

Journal Article · Mon Apr 01 04:00:00 EST 1991 · Geochimica et Cosmochimica Acta; (USA)

DOI:https://doi.org/10.1016/0016-7037(91)90155-X· OSTI ID:5470074

Blowes, D W; Reardon, E J; Cherry, J A ^[1]; Jambor, J L ^[2]

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1. Univ. of Waterloo, Ontario (Canada)
2. CANMET, Ontario (Canada)

Investigations of inactive sulfide-rich tailings impoundments at the Heath Steele (New Brunswick) and Waite Amulet (Quebec) minesites have revealed two distinct types of cemented layers or hardpans. That at Heath Steele is 10-15 cm thick, occurs 20-30 cm below the depth of active oxidation, is continuous throughout the tailings impoundment, and is characterized by cementation of tailings by gypsum and Fe(II) solid phases, principally melanterite. Hardpan at the Waite Amulet site is only 1-5 cm thick, is laterally discontinuous (10-100 cm), occurs at the depth of active oxidation, and is characterized by cementation of tailings by Fe(III) minerals, principally goethite, lepidocrocite, ferrihydrite, and jarosite. At Heath Steele, an accumulation of gas-phase CO{sub 2}, of up to 60{percent} of the pore gas, occurs below the hardpan. The calculated diffusivity of the hardpan layer is only about 1/100 that of the overlying, uncemented tailings. The pore-water chemistry at Heath Steele has changed little over a 10-year period, suggesting that the cemented layer restricts the movement of dissolved metals through the tailings and also acts as a zone of metal accumulation. Generation of a cemented layer therefore has significant environmental and economic implications. It is likely that, in sulfide-rich tailings impoundments, the addition of carbonate-rich buffering material during the late stages of tailings deposition would enhance the formation of hardpan layers.

• OSTI ID: 5470074
• Journal Information: Geochimica et Cosmochimica Acta; (USA), Journal Name: Geochimica et Cosmochimica Acta; (USA) Vol. 55:4; ISSN GCACA; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540320 -- Environment
Aquatic-- Chemicals Monitoring & Transport-- (1990-)
58 GEOSCIENCES
580000* -- Geosciences
ALKALINE EARTH METAL COMPOUNDS
CALCIUM COMPOUNDS
CALCIUM SULFATES
CANADA
CHEMICAL REACTIONS
CHEMISTRY
DEVELOPED COUNTRIES
FLUID FLOW
GEOCHEMISTRY
GOETHITE
GROUND WATER
GYPSUM
HYDROGEN COMPOUNDS
HYDROLOGY
MILL TAILINGS
MINERALS
NEW BRUNSWICK
NORTH AMERICA
OXIDATION
OXIDE MINERALS
OXYGEN COMPOUNDS
PRECIPITATION
QUEBEC
ROCK-FLUID INTERACTIONS
SEPARATION PROCESSES
SOLID WASTES
SPOIL BANKS
SULFATE MINERALS
SULFATES
SULFIDE MINERALS
SULFUR COMPOUNDS
TAILINGS
WASTES
WATER