Modelling Overburden Thickness for Applications in Mining Technologies

Many drift prospecting methodologies using geophysical and geochemical surveys are dependant on overburden thickness to successfully locate mineral deposits. Efficiency of these methods relies on the overburden’s ability to reflect underlying bedrock. Till sampling for geochemistry or indicator minerals in thick overburden may yield data difficult to interpret. A basic knowledge of sediment thickness and glacial sediment genesis and ice-flow history is required. Most models of overburden thickness are developed from subsurface geological data with abundant “depth-to-bedrock” information, in the form of water well logs, drill holes or seismic shot holes. Overburden thickness models can also be developed where there is limited or no primary “depth-to-bedrock” information, or where the primary information, such as drill holes, is clustered. In these cases, a surficial geology map can provide an important source of overburden thickness data. The best approximate overburden thicknesses are derived from surface morphology of the surficial units, obtained from both air photo/satellite interpretation and traditional mapping activities.