UBC Theses and Dissertations
An evaluation of bulk ore sorting potential in a copper-gold panel cave mine Cetin, Mahir Can
Block and panel caving are underground mining methods that allow for extracting relatively low-grade and deeply situated orebodies. Caving differs from other underground mining methods and open pit mining regarding the lack of grade selectivity, which results in both ore and waste reporting to the mill, thereby increasing energy and water consumption and processing waste generation. Bulk ore sorting is a preconcentration method that uses sensors measuring grade directly or indirectly to identify and discard waste material before milling. Bulk ore sorting is proposed as a remedy for the lack of selectivity associated with cave mining; however, the potential to implement the method depends on various geological, operational, technical, and financial factors. The primary goal of this research is to comprehensively evaluate the bulk ore sorting potential in the Cadia East copper-gold panel cave mine using a methodology developed to be applicable for similar caving operations extracting copper porphyry deposits. The developed methodology includes a script package that can perform automated and fast bulk ore sorting assessments. The script package mainly requires ore grades measured at various locations of a cave mine and extraction level layouts. As part of the evaluation, the heterogeneities and bulk ore sorting potentials of the individual panel caves of the mine were estimated for the ideal case. The impacts of sorting cut-off grade and metal price on the ideal sorting performances of the panel caves were determined. A reconciliation study revealed that the mixing during the handling of the ore underground reduced the grade variability more severely than the mixing within the cave, and the opportunity to preconcentrate the ore at the surface was almost entirely lost due to mixing events. The cave footprints were analyzed spatially to locate the orebody portions that might be subjected to bulk ore sorting using sensors on production loaders on the extraction level. Lab-scale tests were performed to determine the grade measurement capability of bucket-mounted X-ray fluorescence sensors that could be used for bulk ore sorting or grade monitoring underground. The sensor tests produced promising results, particularly in determining the copper grades of the samples obtained from the mine.
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Attribution-NonCommercial-NoDerivatives 4.0 International