RECL2019 Soil Reclamation

The evolution of successful soil reclamation practices

The Land Surface Conservation and Reclamation Act introduced the need for soil conservation

Topsoil and subsoil are salvaged together at a surface mine near Grande Cache. 1975
Land reclamation is the process of returning disturbed land to a stable, biologically productive state (equivalent capability). The success of reclamation is dependent upon the development of favourable conditions in the root zone of reconstructed soils.

The 1973 Land Surface Conservation and Reclamation Act introduced the need for soil conservation and planning, recognizing that soil is a valuable resource. This legislation was implemented to focus reclamation efforts on salvage and replacement of soil rather than relying on management practices that would become the responsibility of the land user.

Soil placement requirements dictated soil salvage practices and prompted significant research to determine “how much of what is necessary” for problematic substrates such as sodic spoil or to grow vegetation for specific land uses. 

The evolution of successful soil reclamation practices

The Land Surface Conservation and Reclamation Act introduced the need for soil conservation

Land reclamation is the process of returning disturbed land to a stable, biologically productive state (equivalent capability). The success of reclamation is dependent upon the development of favourable conditions in the root zone of reconstructed soils.

The 1973 Land Surface Conservation and Reclamation Act introduced the need for soil conservation and planning, recognizing that soil is a valuable resource. This legislation was implemented to focus reclamation efforts on salvage and replacement of soil rather than relying on management practices that would become the responsibility of the land user.

Soil placement requirements dictated soil salvage practices and prompted significant research to determine “how much of what is necessary” for problematic substrates such as sodic spoil or to grow vegetation for specific land uses. 
Topsoil and subsoil are salvaged together at a surface mine near Grande Cache. 1975
Topsoil on far right over subsoil layer over graded spoil on left. 1983
Soil quality criteria were developed to provide guidance for soil salvage and subsequent replacement. Use of the soil capability approach to evaluate reclamation success led to development of a number of capability classification systems for different land uses.

Soil salvage practices evolved rapidly from virtually no salvage prior to 1973 to salvage of specific depths and horizons that varied with site characteristics. 
Soil replacement practices similarly evolved from none to just surface soils, to replacement of two or three layers depending on quality of the underlying material. Direct placement (transport of salvaged soil from the pre-disturbance area to the reclamation area) is practiced wherever and whenever possible to reduce soil handling costs, minimize soil degradation and enhance reclamation success. Soil stockpiling for subsequent replacement is required to some extent in all regions.
Oil sands reclamation practices evolved from peat salvage to overstripping, resulting in peat-mineral mixes. This was followed by salvage of the surface organic layer and shallow topsoil. Salvage and replacement are generally conducted during winter because of ease of trafficability and improved soil structure in reclaimed soils. 

In higher elevation mountain coal mines, where surface soils are limited, salvage usually involved a one-lift operation which included the surface organic soil and underlying mineral soil above bedrock. The replaced soil cap needed to be deep enough for planting bare root or container seedling stock. 
Soil salvage at a surface mine near Grande Cache. 1975
In the plains region, soil salvage evolved from no salvage to salvage of topsoil only, then to salvage of topsoil and subsoil. Current replacement practice includes a topsoil layer over up to one metre of subsoil over graded spoil.
Current soil management practices reflect the fundamental importance of soil caps and underlying layers in providing an adequate reservoir for rooting, soil water storage and nutrient cycling.    
Peat-mineral mix placed over secondary material over tailings sand. 1995
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