ESTIMATING RATES OF GROUND RETREAT ON MINING SPOILS USING CESIUM-137

The potential for using the artificial radionuclide caesium-137 to estimate rates of ground retreat on mining spoils is introduced. The Cs-137 contents of cores from slope transects on a regraded opencast infill at Waunafon, Gwent are compared with long-term erosion pin measurements from adjacent slopes. The data suggest an inverse relationship between Cs-137 inventory and measured ground retreat. Additional measurements from an unvegetated slope indicate that Cs-137 depletion is partially explained by topographic factors, particularly slope curvature. Anomalies between the Cs-137 measurements, erosion pin data and erosion estimates from a mass balance procedure are discussed. The results suggest that Cs-137 measurements may provide an efficient means of obtaining data on erosion rates in mining spoil environments but a number of uncertainties remain to be resolved.