Weathering processes under various moisture conditions in a lignite mine spoil from as pontes (N.W. Spain)

Seoane, S.; Leiros, M. C.

Weathering processes under various moisture conditions in a lignite mine spoil from as pontes (N.W. Spain)

1997

Seoane, S. | Leiros, M. C.

Processes contributing to acid release/consumption during weathering of a lignite mine spoil (2.3% w/w S as sulfides) from As Pontes (N.W. Spain) were studied under three moisture conditions (at field capacity or under alternate wetting-drying or forced percolation), which were simulated in laboratory experiments. Oxidation of sulfides to sulfates was favoured under all three moisture conditions, releasing most acid in spoil kept at field capacity. Hydroxysulfates formed in spoil kept at field capacity or under alternate wetting-drying conditions, thereby contributing to acid release. Acid consumption by dissolution of clay minerals, especially micas, was favoured under all three moisture conditions, but was particularly intense in spoil at field capacity. Dissolution of aluminium oxides was also favoured under all the moisture conditions studied.

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