A geotechnical review and considerations in the design of a new mining method at Konkola Mine

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Mutambo, Webby
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Konkola Mine of Konkola Copper Mines Plc comprises of Number 1 and 3 Shafts located on the northern most part of the Zambian Copperbelt. The mining licence area is characterised by the Kirilabombwe anticline dividing the West and North Limbs striking generally in the northwest to southeast directions. Average dip angles are 60in the Central region, very flat (about 10) towards the „nose‟ area and 60in the North. The Number 1 Shaft is located in southern part of the ore body and lies between 0mN to 3000mN survey mark positions and extends to 800mS. The current development is below 3150 feet level. The Number 3 Shaft is located on the North Limb and the lowest tramming level is at 1850 feet level. Production is currently below the 2270 feet level.As mining is focused below 2270 feet level at Number 3 Shaft and below 3150 feet at Number 1 Shaft, there is need to determine a suitable mining method. This must take into consideration the geotechnical parameters of the host rock and the ore body especially in the nose area where several mining methods have been applied. The dip and the depth from surface influenced the selection of a suitable mining method.This research involved collection of scan line mapped data. The data collected includes joint spacing, joint orientation, joint condition and rock samples to determine the uni-axial compressive strength. The collection of data at the mine site was done in two parts: the first part involved collection of the existing mapped data while the second part involved underground mapping. The collected data was analysed using a computer based spreadsheet to determine the rock mass rating and the information was subjected to evaluation using specialised geotechnical Phase2D software.A review of the design and implementation of the proposed mining method has been made with the aid of a computer model using Phase2D. Ground support requirements for the mining method have also been defined. This selected mining method has been analysed based on the productivity and safe extraction way of taking out the ore body in the nose area of Konkola. The results show the options that involve mining of primary and secondary stopes with different stope spans and will require cemented backfill in primary stopes.
Mining Engineering