ABSTRACT
In this research, semi-variograms of different directions, are used to form a three-dimensional variogram surface. A simple and practical surface generation technique, namely bilinear surface fitting method is used for this purpose. Co-variance between any of two sample points (drill holes) can be found on the surface easily. Angle and distance between are used to calculate the co-variance. The aim is to provide a practical approach for data extension in anisotrophic structures. The algorithm is coded in C++ and applied to a real case. Semi-variograms are drawn at 45° intervals. Then, the developed system fits a 3D bilinear surface through semi-variograms. Kriging process is performed and node points on the grid system are assigned the thickness of coal seam and topographic elevation values. Reliability of the approach is examined by cross-validation. The results are reasonable and encourage further detailed studies.
