North-West University, Potchefstroom, South Africa; Mine Water Re-Search Group, North-West University, Vanderbijlpark, South Africa
Schrader, A., North-West University, Potchefstroom, South Africa; Winde, F., Mine Water Re-Search Group, North-West University, Vanderbijlpark, South Africa; Erasmus, E., Mine Water Re-Search Group, North-West University, Vanderbijlpark, South Africa
Some of the world’s deepest goldmines are located in the Far West Rand (FWR) goldfield operating below of up to 1.2-km-thick dolomites hosting some of the largest karst aquifers in South Africa. Associated impacts include the dewatering of the overlying karst aquifers as well as linking previously disconnected compartments by mining through aquicludes (dykes). The focus of the study is on predicting groundwater balances in re-watered aquifers after mining ceases as this will determine whether or not associated karst springs that dried-up due to dewatering will ever flow again. Critically revisiting, Swart et al. (Environ Geol 44:751–770, 2003a) who predict that all springs will flow again, this study uses significantly larger data sets and modified assumptions to increase the robustness of findings as the question is crucial for post-closure development. As a first of two papers, this part develops a conceptual model on the mega-compartment concept that predicts a flat water table across all linked compartments that would leave the springs dry. The model identifies the ratio between inflowing surface water (recharge) and underground water losses to downstream compartments via mined-through dykes (‘inter-compartmental groundwater flow’, IGF) as a key factor governing the elevation of the post-mining water table, creating the base for part 2, where the IGF and the post-mining water tables are determined using unique large data sets that have not been evaluated before. © 2014, Springer-Verlag Berlin Heidelberg.
Aquifers; Dewatering; Forecasting; Gold; Groundwater; Groundwater flow; Groundwater resources; Hydrogeology; Landforms; Springs (water); Surface waters; Conceptual model; Deep-level mining; Dolomitic compartments; Karst hydrology; Large datasets; Mega-compartment concept; Re-watering; Spring flow; Recharging (underground waters); conceptual framework; Darcy law; data set; dewatering; dike; dolomite; environmental impact; gold mine; groundwater flow; karst hydrology; prediction; recharge; water budget; water table; South Africa; Centrostegia thurberi