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UBC Theses and Dissertations

Use of measurement while drilling techniques for improved rock mass characterization in open-pit mines Babaei Khorzoughi, Mohammad

Abstract

Rock mass properties for a mining area are generally determined based on information obtained from the ore - body model (based on exploration data), visual observations in combination with other indices obtained from physical sample testing or geophysical logging. One of these indices is the blastability index. Blastability is generally dependent upon the geological and geomechanical properties of a rock mass in terms of such factors as intact strength as well as the degree and extent of fractures. Accurate determination of the blastability is a critical element that can be used for mine planning towards achieving higher loading and hauling efficiency through more optimal fragmentation. Based on previous works, a reasonable estimate of the rock mass blastability has been shown to be derived from the performance monitoring of blasthole drills using tricone bits. The current work aims to build upon the previous efforts through the creation of a comprehensive model and approach that can predict a range of blastability results for a broad array of variables such as: operating conditions, structural features, etc. More specifically, the research will evaluate and enhance an Alpha Blastability. Index Algorithm (Compensated Blastability Index) originally defined by a mining technology company (Peck Tech Consulting Ltd.) in 2008. This Alpha CBI algorithm was never fully tested, validated nor verified in terms of its ability to consistently and repeatedly generate accurate blastability data. The Alpha CBI algorithm was based on Measurement While Drilling (MWD) data and an associated suite of geophysical logs for the same blastholes during comprehensive field studies in an open-pit copper operation in British Columbia, Canada. The improved Alpha CBI algorithm that results from the current research has been designed to use drill monitored data to generate improved blastability indices that provide more detailed information on in-situ rock mass properties than the previous approach. It accomplishes this by an enhanced ability to identify zones of fractured rock and subsequently compensating for their presence. The resulting blastability indices thus derived through this new method have been shown to more closely reflect the true in-situ rock mass conditions as validated when correlated to the geophysical logs.

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Attribution-NonCommercial-NoDerivatives 4.0 International