Abstract mv$gL
The collection of geomechanical data in the mining industry is often hindered by limited access to rock exposures. Consequently, o9]!*Y!RA
there is a need for a tool that permits fast and safe acquisition of information that best characterizes a geological structural regime. iM8l,Os]<f
This paper presents a digital face mapping methodology used to construct discontinuity trace maps from photographs of rock faces. @qA11C.hq
The method is applicable under a range of ground conditions, while at the same time trying to keep user intervention to a minimum. sVnpO $
The developed procedure uses a series of photographs of a rock face taken under symmetrical lighting orientations. All digitized (CYQ>)a
pictures are then introduced into the developed software, where pre-processing optimizes subsequent analysis. Discontinuity traces Tz\v.&? $
are then extracted from the enhanced images using edge and line detection algorithms. This results in a binary image where black 1^WkW\9kO
pixels correspond to the detected features. The nature of these features is identified using artificial neural networks, specifically KYg'=({x
trained for this application. As a result, it is possible to distinguish between segments in the image that are due to the presence of a
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discontinuity and those due to other phenomena. This classification process provides a series of binary images that represent AuB BSk8($
discontinuity traces in the area of interest. These images are superposed and merged. All processes described above are fully ,n>K$
automatic. In order to complete the process, the system operator ensures that incomplete discontinuity segments are reconstructed. [ 8 WG
Following this, a discontinuity trace map is constructed and the discontinuity network is characterized using geomechanical criteria. {G|= pM\'
The methodology to construct discontinuity trace maps is illustrated using an example from a rock exposure in an underground Ycxv=Et
mine. Subsequently the methodology is implemented in two case studies from underground mines and one in a quarry. These case LTb#1JC
studies represent different geological and lighting conditions. This information is then used to successfully characterize the >4=7t&h
investigated rock masses. Present limitations of the method are also identified. W E
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r 2003 Elsevier Ltd. All rights reserved.
