ISSN:
1432-0495
Keywords:
Sulfide oxidation
;
Chemical modeling
;
Ground water chemistry
;
Brown coal mining
;
Hydrochemistry
;
Soil gas
;
Pyrite oxidation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Geosciences
Notes:
Abstract Surface mining of brown coal in the Rhineland brown coal mining area (Germany) causes acidification of pyritic sandy overburden sediments. Convective transport of air, indicated by an enrichment of nitrogen gas in oxidized overburden, is, in addition to diffusion of oxygen, the driving mechanism for sulfide oxidation. Products of sulfide oxidation (2SO4 2− + 2H+ + Fe2+) stored in acidic material in the overburden dump are leached by groundwater filling the dump and react with the carbonate phases of nonacidic material. The resulting hydrochemical composition (up to 6000 mg l−1 SO4 2−, 3000 mg l−1 Fe2+, pH 4.5) in groundwaters is controlled by simultaneous solubility equilibria with CaSO4·2H2O(s), Fe(OH)3(s), Fe0.9Ca0.1CO3(s) and CO2(g). Calculated equilibrium concentrations of major components and pH in groundwater, partial pressure of CO2(g) in soil gas, and coupled mass transfer match observed conditions.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00768742
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