Assessing geological vein size and intensity using Discrete Fracture Network modelling at the EI Teniente Mine, Chile.

摘要

Using the commercial FracMan software package, discrete fracture model (DFN) of the geological stockwork veins has been built at the El Teniente mine that honoured data collected in drill cores and mine drives. DFN models explicitly represent key vein structures in 3D and require as a minimum data, the orientation, the size and the intensity of the veins to be defined. The orientations of the structural data observed in oriented cores were used to bootstraps veins orientations within the modelled volume. The correlation between observed and simulated orientation data sets was evaluated by applying Chi-Square tests and the results were outstanding. Vein size was assessed through applying the simulated sampling technique to match the observed trace length measurements collected in wall mine drives. The results showed the stockwork veins as having small size with a mean around 1.0m for both lognormal and exponential size distributions. Discontinuity intensity was determined by conditioning linear vein frequency of the three different core measurements using vein orientation and size properties determined in previous modelling steps. Veins intensity, measured as the area of fracturing in a unit volume, was estimated as 46m~2/m~3,but for veins that control fragmentation and caving propagation, intensity values were estimated between lm~2/m~3 and 5m~2/m~3.