Waste-rock piles

Site 2 is situated on the south shore of Moore s pit (Figs. 1 2b). This site consists of i) a pyritic waste rock pile, covered with a thin veneer of Fe-oxide tailings and ii) a down stream acid drainage affected area that is characterized by a Fe oxide + sulfur-rich hard pan surface layer that overlies a stratified unit comprised of intensely altered (Fe-oxide stained) and unaltered Quaternary glaciolacustrine deposits. A small creek (product of beaver activities) flows along the eastern margin of the site into Moore s pond. 

In this work, 6 Lac Tio waste rock samples are investigated 3 samples were freshly blasted waste rock and 3 were weathered samples from an old waste rock pile (approximately 25 years old) which underwent significant natural alteration. The ilmenite content varies from approximately 20 to 60 wt% in both... 

This study allows a better understanding of the Ni geochemistry in near-neutral conditions. Kinetic cell tests run for 75 weeks on 6 waste rock samples suggest that the pH will remain near neutral in the waste rock piles. Sorption phenomena seem to drive Ni leaching in laboratory kinetic cells, and the sorption type and capacity vary between fresh and... 

The rate of oxygen diffusion is proportional to the diffusivity of the waste-rock pile. Although the diffusivity of waste rock is high because of the low moisture content of the waste rock, diffusive transport of oxygen is sufficiently slow that this process limits the rate of sulfide oxidation. Advective transport of oxygen results from changes in gas pressure between the waste-rock pile and the atmosphere. Wind has the potential to drive oxygen deeper into the pile than would occur... 

Figure 7 Measurements of temperature and oxygen concentration in the Rum Jungle mine waste-rock pile (after Harries and Ritchie, 1985).

Of basic importance when determining risk is the absolute and relative amounts of the exposed pyrite that occur above or below the water table. Above the water table, oxidation rates are usually catalyzed by bacteria and can be very fast in fine-grained waste-rock piles. Rates in water-saturated spoil materials or below the water table are generally much slower because of the unavailability of free oxygen. 

Cotter-Howells ID, Champness PE, Chamock JM (1999) Mineralogy of Pb-P grains in the roots of Agrostis capillaries L by ATEM and EXAFS. Miner Mag 63 777-789 Courtin-Nomade A, Soubrand-Colin M, Marcus MA, Fakra SC (2008) Evidence for the incorporation of lead into barite from waste rock pile materials. Environ Sci Technol... 

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