Identification of Soil-Water Chemical Parameters for the Prediction and Treatment of Suspended Solids in Surface Water Reservoirs of Coal Mine Lands

High concentrations of suspended solids in coal mine sedimentation ponds are a factor in lowering water quality. This study focuses on the influence dissolved solids have on concentration and settling of suspended solids. Water samples from sedimentation ponds in Eastern and Western Kentucky were used to evaluate water composition in such ponds. Spoil samples from surface mine sites in both parts of the state were used to evaluate water composition released from the spoils upon introducing water. The results demonstrate that water quality emanating from coal spoils of Eastern and Western coal mines is dependent on the type of spoil and/or geologic strata represented. Water composition of randomly selected sedimentation ponds revealed that the relationship between electrical conductance (EC) in mmhos cm-1 and ionic strength (I) of water is I = 0.012 [EC]. Furthermore, it was determined that there is a linear relationship between the repulsive index, RI = [(0.012)(EC)]-1/2 (based somewhat loosely on double-layer theory), and suspended solids. Kinetic data on settling of suspended solids has shown that upon increasing the ionic strength of the water (consequently decreasing RI), the rate of settling increased dramatically. The critical RI at which complete removal of all suspended solids, estimated by graphic extrapolation, is shown to be dependent on the percent base saturation. The data also demonstrate that the critical RI (RI at maximum flocculation) varies depending on the spoils mineralogical and chemical composition. The overall study shows that decreases in suspended solids in coal mine sedimentation ponds can be brought about by relatively small increases in ionic strength. Several approaches as to how one might increase water ionic strength in sediment ponds are discussed

Identification of Soil-Water Chemical Parameters for the Prediction and Treatment of Suspended Solids in Surface Water Reservoirs of Coal Mine Lands

High concentrations of suspended solids in coal mine sedimentation ponds are a factor in lowering water quality. Colloidal particle settling simulations were carried out in the laboratory to test the influence pH and dissolved solids have on concentration and settling rates of suspended solids. The results of the study reveal that the pH range of colloidal coflocculation for the samples tested is between 3.5 and 4.5. Furthermore, liming simulation of acidic sediments, as expected increased colloid dispersion. This increase was dependent on the magnitude of the sodium adsorption ratio (SAR). The greater SAR systems maintained a greater concentration of colloidal suspended particles. However, for the same SAR value when the ionic strength was increased from 4 meq L-1 to 8 meq L-1, sedimentation rate of colloidal particles decreased. The data also show evidence that for the same SAR values when substituting magnesium for calcium, the rate of particle settling increased for one sample but decreased for another. This unexpected behavior is under further investigation

Grain Sorghum and Soybean Variety Tests on Reconstructed Prime Land - 1985

Prime farmland disturbed by surface mining must by law be returned to a productivity level equal to that before mining. The coal operator has several test crops that can be selected to determine whether these production standards have been met before final bond release will be made. Grain sorghum and soybeans are two of the crops that may be used. The purposes of this research are (1) to determine the crop yield potential of restored prime farmland from surface mined areas, (2) to determine varietal adaptation on restored prime farmland as compared to non-mined prime farmland, and (3) to provide crop yield data to Kentucky farmers on grain sorghum and soybeans from restored prime farmland

Gross Nitrogen Transformation Rates in Soil at a Surface Coal Mine Site Reclaimed for Prime Farmland Use

Organic wastes were used to increase N fertility at a surface mine reclamation site, with the ultimate goal to stimulate microbial activity and improve the reclaimed soil\u27s chemical and physical properties. Gross N transformation rates are indicators of microbial activity but are undocumented in such reconstructed ecosystems. We measured gross nitrification, N mineralization and N immobilization in waste-amended and unamended soil using 15N pool dilution techniques. Measurements were made in June, July and November 1993 at the reclamation site in western Kentucky, and compared to net N transformation rates. The premise that organic waste amendment stimulates microbial activity in reclaimed soils was supported by the data. Gross N mineralization, nitrification and immobilization rates were as much as 4.5 times greater in waste-amended soil than unamended soil. Gross N mineralization and nitrification rates and gross NH4+ and NO3− immobilization rates were significantly greater than net rates in waste-amended and unamended soil. There was net immobilization of NH4+ and NO3− in waste-amended soil, whereas there was net N mineralization in unamended soil. This was consistent with using substrates containing high C-to-N ratios. Reclamation practices created soil environments in which gross N transformation rates were of the same magnitude as those measured for less disturbed soil ecosystems