Investigating in situ variability and homogenisation of key quality parameters in continuous mining operations

Abstract

The delivery of in-spec qualities out of the mine is essential for an efficient and environmental friendly operation of the subsequent beneficiation process. One goal of the extraction and production process in mining operations is to reduce the deposit inherent grade variability to a usually contractual defined level. The design of blending opportunities along the mining chain plays a key role in homogenising variability and improving the prediction of key parameters, such as the calorific value in the case of coal deposits. Geological conditions of deposits to exploit are becoming more complex. Typical currently exploited coal deposits in Europe are already characterised by multiple seams with multiple splits, each split representing a different variability in seam geometry and quality. Modern methods of conditional simulation in geostatistics allow for generating several spatial models or possible scenarios for large deposits capturing in situ variability. Integrating simulated models with the excavation sequence and transport and blending models of the mining operation leads to valuable insights into the expected performance as a function of the technical design and operational mode. The presented case study uses the technique of conditional simulation in geostatistics to investigate the variability of the calorific value in exploiting a complex lignite deposit. The study analyses the behaviour along the extraction, transportation and blending process in a continuous mining environment. Results provide valuable inside into the performance of a continuous mining system in terms of homogenisation and allow identifying sources for controlling variability. Conclusions can be drawn to adjust the mine design and scheduling of key equipment as well as to adjust the operation mode according to the customer's requirements in terms of coal quality variability.