Study On Three-dimensional Orebody Surface Modeling Algorithms

A three-dimensional orebody surface model is extremely useful for the comprehension of complex orebody structure, and thus can be used as a guide for the planning and production of metal mines. However, so far there are no complete and sound algorithms available for three-dimensional orebody surface modeling and many problems still remain to be solved.Through an in-depth study of three-dimensional orebody surface modeling theories and techniques, the author proposes in the paper a new approach of reconstructing3D orebody surface from a set of planar contours, to be specific, geological section contours. The algorithm is named Constraint-conditions-based Synchronization-first Shortest Diagonal Algorithm (CCBSFSDA).As we know it, it is a commonplace in the medical imaging industry to reconstruct3D surface from planar contours. But due to their limitations, these algorithms usually end up with failure if used as it is, in3D orebody surface reconstruction, especially when adjacent contours are too different in shape, or the number of nodes for one contour completely outweighs that for the other, or their structures appear extremely complex. As a result,"cones" or "partial cones" and "dangling edges" are formed as such. By introducing a control parameter, namely Synchronization Constraint Ratio (SCR), to the algorithm proposed, the problem is solved to some extent. The underlying principle is this:by making a comparison of the forward speed of the respective pointers for adjacent contours as well as the stride distance of the attempted next moves, and thereby taking appropriate intervention steps as advised by the algorithm, the triangulation is assured to occur synchronously along the paths. However, there are times when the overall shape of adjacent contours looks similar, but some parts, usually rather small, differ greatly. This is also addressed in the algorithm so that reasonable synchronization is guaranteed and no distortion or misconnection would ever take place. The effectiveness and efficiency of the algorithm have been proved in an experiment to model the No.3Iron Orebody of Nanfen Open-pit Iron Mine in Benxi. The solid orebody reconstructed with the algorithm looks both smooth and natural.Branching and correlating of contours, among other things, need to be done prior to surface reconstruction. The process is detailed in the paper. In addition, tailing-out is also discussed.A three-dimensional orebody surface modeling module developed by the author with C++Builder can either run standalone or be used as an interface ready to be called by any third-party software that conform to the protocols required by the algorithm. UML (Unified Modeling Language) is used throughout the development cycles for visual representation and easy communication, whether it is in the requirement analysis, general design or detail design phases.