Stripping ratio plays a major role in the profitability of open cast mines. Precise digital elevation models and other interpolation surfaces used for overburden volume definition are required. This paper uses ordinary kriging to build a 3D overburden model and conditional simulations to model multiple scenarios for the deposit tonnage. The former permits to obtain the best interpolated models. The second provides the tools to assess the uncertainty in mineral resources. Combining overburden volume model and multiple models for the deposit tonnage makes possible to evaluate the range of equally probable expected stripping ratios. The methodology is demonstrated in a clay deposit in Southern Brazil.
stripping ratio; risk; geostatistical methods
