Phenomenology of Control Blasting in Close Proximity to Densely Populated Communities: A Case Study of Mopani’s Area J Open Pit

Mwale, Timothy (2016) Phenomenology of Control Blasting in Close Proximity to Densely Populated Communities: A Case Study of Mopani’s Area J Open Pit. Masters thesis, University of Zambia.

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Abstract

Blasting is the process of fracturing material through the detonation of industrial explosives placed into drilled holes suitably located to a free surface. Every blast hole containing a calculated amount of explosive charge undergoes impulsive loading when detonated and results in the dynamic transfer of a powerful shock wave to the surrounding rock. It is this shock wave that brings about rock breakage when the tensile stress is produced after the stress wave reflects on the free face or change in material density of rock material tensile strength. However, this shock wave comes along with unwanted destructive consequences such as ground vibration, noise and flyrock. The consequences highlighted above are likely to affect the Wusakile Community in Kitwe as Mopani Copper Mines (MCM) Plc. wishes to expand the pit towards the community that lies within 150m from the pit rim. As part of the commitment given by MCM to the Zambia Environmental Management Agency (ZEMA), all blasting operations close to a community must maintain at least below the maximum vibration threshold of 10 mm/s with no flyrock. Furthermore, all noise levels must be kept below the maximum threshold of 134dB in order to reduce environmental concerns raised by the community. In order to meet the above requirement, the phenomenology of rock breakage and other factors such as the maximum projection distance, size of the fragment, shape of the fragment, angle of projection, the state of confinement of an explosive charge, design faults, deviation in implementation and unforeseen geological conditions were considered during the study. Analysis of data showed that vibrations directed towards the community were kept below the maximum acceptable limit of 10mm/s. Furthermore, all higher vibration readings recorded at MCM Synclinorium offices were quickly dumped on the subsequent seismograph positions located at Kalela Basic School thereby confirming its dumping effect. In addition, no flyrock was observed to have gone beyond the safe blast limit of 100m and over 90% of crack monitors on cracked houses revealed no expansion during the project life. This dissertation therefore illustrates the possibility of conducting blasting operations close to a community with improved fragmentation while mitigating all adverse effects to the environment by use of controlled blasting techniques. It further suggests the possibility of incorporating such blasting techniques and their threshold values onto the Zambian Regulations.

Item Type:	Thesis (Masters)
Subjects:	T Technology > TN Mining engineering. Metallurgy
Divisions:	Africana
Depositing User:	Geoffrey Obatsa
Date Deposited:	02 Aug 2018 12:36
Last Modified:	02 Aug 2018 12:36
URI:	http://thesisbank.jhia.ac.ke/id/eprint/8259

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