ABSTRACT
Oxygen consumption was investigated in covered pyritic mine waste deposited on land near Maarmorilik in West Greenland. Pore gas concentrations of oxygen and carbon dioxide were measured in waste and in cover material. Samples of mine waste were collected for calorimetric evaluation of site-specific and temperature-dependent sulfide oxidation. To evaluate the mineral composition of waste material, additional samples were taken for quantitative X-ray diffractometry. Results show that reactive pyrite grains exist below the cover material and that pyrite oxidation results in an oxygen gradient across the cover. The rate of oxygen consumption was generally low, which is consistent with the observed pH values between 8 and 9. However, a sample from a spill of pyritic sediment near the covered area indicates that sulfide oxidation occurs at high rates, in accordance with the high concentrations of heavy metals observed in water draining from the area.
