The objective of reclamation of surface mined lands in the Athabasca Oil Sands Region in northern Alberta is to return the land to an equivalent land capability. The native soils disturbed by surface mining must be salvaged and replaced during reclamation in accordance with the current provincial legislation, consequently, the topsoil (LFH or Ah, Ahe, Ae, Oa, Oi, Oe horizons) and subsoil (B and C horizons) or upper two meters of organic soil are removed and stockpiled during overburden and resource extraction activities and are replaced over tailings sand or overburden during reclamation. The objective of this research was to assess the carbon (C) balance within the reclaimed landscape by monitoring the soil, biomass and dead organic matter carbon pools from the time of initial reclamation forward at the operations of Syncrude Canada Ltd. To achieve this objective C losses and gains were monitored through respiration and biometric assessments, respectively. These methods were then used to evaluate the C dynamics of various reclamation strategies and soil prescriptions compared to targeted natural undisturbed ecosites. Net C accumulation was determined using biometric measurement techniques for three years at several long-termmonitoring sites representing six soil cover prescriptions and three of the most common natural soil types. Measurements of the annual production of above and below ground C biomass and soil respiration were used to develop biometric estimates of net ecosystem productivity. The soil component comprised a substantially larger proportion of the total C pools in the reclaimed areas. The soil C pool was larger for all reconstructed sites with a peat-mix or LFH cap than for the natural sites, especially sites with mature tree stands 70 years of age or greater which had substantially more C stored in the above ground biomass than in the soil. Measurement of inputs to and output (losses) from the total C pool for reclaimed sites with different soil covers indicated that losses were nearly balanced by inputs in the early years following revegetation.

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Abstract; In 1983 the Alberta Research Council and Luscar Ltd. initiated a study to monitor the physical and chemical properties of newly mined and reconstructed soils at the Paintearth Mine. The objective was to determine what changes were occurring and the impact, if any, of these changes on long-term soil quality and productivity. Baseline soil sampling and neutron access tube installation were completed shortly after spoil leveling and soil replacement at six locations representing different slope positions and thickness of replaced subsoil. Monitoring sites were also established in unmined soils adjacent to the mine area. Neutron probe measuremen!S to determine soil moistute and bulk density status in the upper 4 m were conducted annually from April to October. Forage crop harvests were completed to determine yield and forage quality in three different years. Sampling of soils in 15 cm intervals to a maximum depth of 210 cm for analytical purposes was completed in seven of the ten years of the study.Soil moisture data indicated that moisture content and distribution pattern in the reconstructed soils were similar to that of adjacent unmined soils. Bulk density at the reconstructed sites decreased with time during the term of the project and was similar to the bulk density values measured at unmined sites. The electrical conductivity data indicated salts were leached or rediJ,tributed downward in the profiles over time. Measurements to date indicate that in terms of soil moisture regime, bulk density status and forage yield the reconstructed soils are similar to unmined soils in the area. The overall improvement in the chemical properties of the reconstructed soils from the time of reconstruction could be largely attributed to leaching of salts.