Mining Simulation Incorporated with Information on Rock Discontinuities.

In order to efficiently operate a mining system, it is important to construct the computer aided mine design and planning systems. These systems, which require the information concerning topography and geology of planned site, estimate optimum mining method, investment effect and changes in scene with the progression of mining. This paper presents the methods to construct a highly precise terrain model and to estimate appearance patterns of rock discontinuities on the model for mine design.In this study, a quarry located at the northern Kumamoto prefecture near the northern limit of Beppu-Shimabara Graben is chosen as the subject area. First, the characteristics of the five fracture zones observed in the planned site are revealed by the analysis of X-ray diffraction, summit levels, azimuth frequency of lineaments and joints. As a result, it is shown that clay minerals are conspicuous in the fracture zones, and that the strikes of the zones are parallel to the dominant trends of the fracture systems on several scales in the graben occurred in the regional tectonic stress field. Furthermore, the maximum gradient method is proposed to generate DTMs (Digital Terrain Models) with arbitrary dimensions of mesh intervals from the contour lines traced by a digitizer. Directions, dimensions and locations of center of the five fracture zones are used for an example of the mining simulation with information on rock discontinuities such as fracture zones. The changes in appearance of those fracture zones on mining slopes and floors with the progression of mining are simulated and clearly shown on the computer graphic screen.