This article presents an investigation for evaluating the relationship between calorific value of lignite and its spatial position using non parametric statistics. Measuring dependence between calorific values and spatial positions is important for production planning and making decisions. For this purpose, a three dimensional data set (easting-x, northing-y, and elevation-z) obtained from Afsin-Elbistan lignite deposit is employed. Rank correlation measurements have been carried out between spatial dimensions and calorific values. In addition, the significances of rank correlation coefficients have been appraised using hypothesis tests. As a result of the study, a strong rank correlation between y and calorific values and a weak rank correlation between z and calorific values are observed, respectively. On the other hand, very low-rank correlation between coordinate x and calorific values is measured for the deposit.