Revealing Variation Of Ore Body By Variogram And Its Application In Optimizing Exploration Grid

The variation of ore body is critical for determining reasonable exploration grid. The variogram has been demonstrated as the most effective method for revealing the variation of ore body. The Dongguashan copper deposit, as the largest the copper deposit in the Yangtze River Metallogenic Belt, is a typical example that the mining has been influenced by the overestimated exploration grid. In this thesis, based on comprehensive comparison of common used methods for generating exploration grid and geological investigation, the variogram method is used compute grade variogram of different segment of the ore body, computational simulation is used to reveal the 3D variation of the grade, and the boundary moduls are calculated to indicate the variation of ore body shape. The optimized exploration grid is determined through systematical analysis of variation of ore body in the Dongguashan copper deposit. The outcomes of this thesis include the following 4 aspects.(1) The major ore body (ore body I) shows great variation in its shape, thickness and grade, which was underestimated during the exploration stage. So the used exploration grid is not thick enough to control its shape and grade.(2) Although the general outline of the ore body is almost stratiform, the detailed shape of the ore body boundary is very complex. The variation of the ore body thickness is not so great as the variation of ore body shape, which is related to intrusion, with the thick segment near the intrusion and the thin segment apart from the intrusion.(3) The variation of ore grade, associated with the variation of the ore body shape, is not identical within the whole ore body.(4) According to the experimental semi-variogram of different segment of the ore body, it is suggested to use the grid of 20×13m to explore the south to the profileⅣ, and 31×10m to explore the north to profileⅣ...