Mineral Sands Mine Reclamation

Since 1990 Virginia Tech has cooperated with Iluka Resources Inc and their predecessor (RGC Mineral Sands Inc.) on a variety of environmental issues related to the development of the Old Hickory and Concord heavy mineral resources.

Our agricultural soil reconstruction research initially involved greenhouse experiments to explore plant growth response to various mixes of tailings (sand) and slimes (clay and silt). This led to the development of preliminary reclamation strategies for the return of the mined area to row-crop productivity. Subsequently, an intensive mine soil reconstruction experiment was installed over pilot-scale mining pits to characterize and compare soil properties and crop productivity on the reclaimed mine soils vs. directly adjacent undisturbed soils. This field study also directly compared productivity of reconstructed mine soils with and without topsoil replacement.

Since mining was initiated in 1997, we have mapped and characterized chemical and physical soil properties within reclaimed mining pits. This included hundreds of auger observations of mine soil profiles in various reclaimed pits and detailed soil profile descriptions and classification of 30+ backhoe pits. We also monitor water quality in a former mine pit which was reclaimed with biosolids applied at reclamation rates under Virginia Department of Health research provisions.

In 2004, Iluka Mineral Resouces, Inc., Virginia Tech and the Carraway-Winn family (local landowner) joined forces to establish the Carraway-Winn Research Farm. The 97 acre farm enabled comparison of different mine soil reconstruction strategies for the return of mined lands to agricultural production.  Reconstruction treatments including topsoil replacement and biosoilds application were evaluated for both row-crop and pasture management systems. The relative effectiveness of deep ripping/tillage treatments to ameliorate adverse subsoil physical conditions was also studied.
 

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