Soil moisture and bulk density monitoring at Syncrude Canada Ltd.

Authors: Drozdowski, BL; Faught, RL; Underwood, A Download Paper

DOI https://doi.org/10.36487/ACG_rep/1152_16_Drozdowski

Cite As:
Drozdowski, BL, Faught, RL & Underwood, A 2011, 'Soil moisture and bulk density monitoring at Syncrude Canada Ltd.', in AB Fourie, M Tibbett & A Beersing (eds), Mine Closure 2011: Proceedings of the Sixth International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 143-152, https://doi.org/10.36487/ACG_rep/1152_16_Drozdowski



Abstract:
Soils disturbed by surface mining in the Athabasca oil sands region must be salvaged and replaced during reclamation in accordance with the current provincial legislation. Historical replacement strategies have been dependent on mining approval conditions, waste materials and targeted vegetation. To determine if the reconstructed soils provided adequate moisture for the post-reclamation vegetation community, a long-term monitoring study was established. Thirty-seven sites were established and monitored for soil moisture and bulk density in reclaimed soil covers and natural soils from 1994 to 2010. During the course of the study, the natural coarse textured Brunisolic (Cryochrepts and Dystrochrepts) soils had volumetric water content values ranging from approximately 3 to 10% and the finer textured Luvisolic (Boralf) soils had values ranging from 17 to 30% during the growing season. Reconstructed soils had moisture contents ranging between the Luvisolic and Brunisolic soils and the most seasonal variability occurred in the soil caps with the finer textured secondary layer and to a lesser extent the peat-mix over tailings sand cover. Based on laboratory derived available water holding capacity, all of the reconstructed soil covers were capable of holding more water in the upper metre of soil than the coarse textured natural soil and were variable (45–138%) compared to the fine textured natural Luvisolic soil. Bulk density of the reconstructed soil covers ranged from 1.4 to 1.7 Mg m-3 which was similar to the values for the finer textured Luvisolic soil. The underlying tailings sand had values of approximately 1.4 Mg m-3 which were similar to the values for the coarse textured Brunisolic soils. Results of the research indicate that current reclamation practices are appropriate for providing soil moisture to support vegetation covers.

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