@mastersthesis {51828,
	title = {Characterizing the geochemical reactions in overburden waste pile: Syncrude Mine Site Fort McMurray, Alberta, Canada},
	year = {2005},
	month = {01/2005},
	pages = {145 pages },
	school = {University of Saskatchewan Department of Geological Sciences },
	address = {Saskatoon, SK },
	abstract = {Potential environmental risks of constructing waste piles from sulphide-bearing saline- sodic overburden include acid-mine drainage and salinization of surface soils. Acid-mine drainage may result from the production o f sulphuric acid during the oxidation o f sulphide minerals. Acid production during the oxidation o f sulphide minerals may also increase the concentrations of S04 (from sulphuric acid), Ca (from dissolution of carbonates), and Na (from cation exchange with saline-sodic overburden) in surface soils. To identify and quantify these potential environmental risks, in situ S04and Caproduction rates were calculated using two different methods. Sulphide mineral oxidation rates were calculated using simple one-dimensional analytical modelling (assuming diffusive gas transport) of in situ pore-gas 02 concentrations. Ca loading from carbonate mineral dissolution (resulting in C02 production) was also calculated using the simple one-dimensional modelling of measuredpore-gasC02concentrations. Massbalancecalculationsusingsolidsample chemistry (totalS, soluble ion and TIC concentrations) were also used to quantify the rate of S04 and Ca production rates. Geochemical and geotechnical parameters controlling acid production and salt loadings were measured by installing gas probes to a depth of25 m (n = 34) for in situ pore-gas 02, C02, CH4 and N2 concentrations, and b13Cc02 values), diviner tubes to depths of 1.6 m (n = 3; for shallow moisture contents), a neutron access tube to 25 m (for deep moisture contents), and a thermistor string to 20m (for temperatures). Pore-gas 02, C02, CH4 and N2 concentrations were measured using a field-portable gas chromatograph. Depth profiles of solid sulphur (samples stored in anaerobic chambers) and carbon concentrations and forms were measured and used for acid-base accounting. Pore-gas chemistry showed that 0 2concentrations decreased from atmospheric to less than 13\% at 5 m depth. C02concentrations increased from atmospheric (0.04 \%) to less than 4\%at the same depth The () derived primarily from an inorganic carbon source. The moisture content data indicated higher moisture contents between 0.5 and 2.5 m depth than at greater depths in the profile. The pore-gas chemistry in conjunction with solids chemistry suggested the presence o f an oxidation zone (acid producing) in the top 3m ofthe profile. However, the results suggested that the oxidation zone was limited to the top 3 m ofthe profile by the presence ofasaturatedshalezone. Acid baseaccountingresultssuggestedthattheacid-producing potential o f the shale only slightly exceeded the neutralization potential (NNP = -6.5). The rates of02 and C02flux through the reclamation cover were estimated to be 0.07 moles 02/m2/dayand0.03molesC02/m2/day. The corresponding sol-production and CaC03 dissolution rates were estimated to be 1.3 and 4.2 g/m2/day respectively. These results were in keeping with rates estimated from mass balance calculations. The results show that a current moisture content conditions, the waste pile was not at risk for acidification or salinization.},
	keywords = {acidity, alkalinity, laboratory, model, modeling, overburden characteristics, pH, sulphur and SO2, Syncrude, UofS},
	url = {http://library.usask.ca/theses/available/etd-07112012-152130/unrestricted/Wall_Susan_N_2005_sec.pdf},
	author = {Wall, Susan N.}
}
