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Research History
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 heavy mineral resource. Our agricultural soil reconstruction research initially involved greenhouse experiments to explore plant growth response to various mixes of tailings/slimed, which 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 our efforts shifted to mapping and characterizing 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. Water quality monitoring was initiated in 2002 for one former mine pit which received land-application of biosolids at higher than agronomic rates under Virginia Department of Health research provisions.
Current Research
The Carraway-Winn Reclamation Research Farm Maps
In 2004, Iluka Mineral Resrouces, Inc., Virginia Tech and the Carraway-Winn family (local landowner) joined forces to establish the Carraway-Winn Research Farm (CWRF). The 97 acre farm enables comparison of different mine soil reconstruction strategies for the return of mined lands to agricultural production. Reconstruction treatments including topsoil replacement and biosoilds application are being evaluated for both row-crop and pasture management systems. The relative effectiveness of deep ripping/tillage treatments to ameliorate adverse subsoil physical conditions also is being studied. To enable comparisons of soil characteristics and crop yields from the CWRF with that of un-mined soils, a control area was delineated on the neighboring Clarke family farm. In addition to these research plots, an entire reclaimed tailings pit is being used to evaluate the growth of different varieties of Bermudagrass.
Twelve groundwater wells, ranging in depth from 5 t 30 ft, have been established around the CWRF to monitor for any impacts from reclamation treatments on groundwater quality. Although elevated nitrate levels have been observed in some of the shallower wells no other significant water quality issues have been observed. |
