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Bismarck Soil Survey Staff Completes Order 2 Soil Survey of Reclaimed Mine Lands

The Bismarck Major Land Resource Area (MLRA) staff recently completed Order 2 soil survey of reclaimed mine land. North Dakota contains some of the largest deposits of lignite coal within the United States. These deposits are a tremendous economic asset to the state with 32 million tons of coal surface mined annually resulting in over 50,000 acres of anthropogenically disturbed soils. A state mandated reclamation process administered by the Public Service Commission (PSC) restores agricultural productivity to premine levels. A soil survey of these areas was needed for conservation and resource planning as well as producer eligibility for farm programs.

Surface coal mining operation.

Surface coal mining operation.

Reshape and grading of a post mine area.

Surface coal mining operation.

Mapping Process

The Falkirk Mine (North American Coal) represents most of the surface mined lands in the Central Dark Brown Glaciated Plains. Soils at the Falkirk Mine have been constructed through the placement of the spoil, subsoil, top soil during reclamation. Information on magnitude of disturbance, respread layer thickness, spoil chemistry, and post mine topography were provided by the PSC and mine staff. This data was critical in setting up soil series and defining mapping protocols. 

Aggregated respread zones along with a post mining elevation and curvature data was used to model the landscape, design map units. The first step in the mapping procedure was to use the re-spread data to pull out the potential soil series. Topographic data from the mine was used to create a classified slope gradient and shape. The final step in the mapping process was field checking the map unit delineations to assure accuracy.

The resulting product was an Order 2 soil survey with established anthropogenic soil series, map unit descriptions, soil physical and chemical properties, and soil interpretations suitable to assist in future management of these soils. 

Delineations based on soil series.

Delineations based on soil series.

Refined delineations on slope.

Refined delineations on slope.

Soil survey product.

Refined delineations on slope.