Joint simulation of coal quality attributes using a new simulated annealing-based method of diagonalisation

ABSTRACT A new approach is proposed for simultaneous diagonalisation of variance-covariance matrices to generate spatially orthogonal factors using based on simulated annealing method. Simultaneous diagonalisation was applied to three quality attributes of a coal seam. The proposed method was successful in diagonalisation due to creating factors with cross-variograms that lie in tighter intervals compared with minimum/maximum autocorrelation factors (MAF). Simulation through the proposed approach showed variable dependent results in terms of reproducing mean values, variances, correlation coefficients, and auto-variograms of variables. However, the new approach showed advantage over MAF in reproducing the cross-variograms of variables, especially in the downhole direction.