MICROWAVE ASSISTED MECHANICAL BREAKAGE OF ROCKS FOR MINING APPLICATIONS

CIM Edmonton 2008
Ferri Hassani, Peter Radziszewski,
Abstract Rock drilling and mechanized boring operations have gone through numerous evolutionary developments over the last century. However, these technologies could be dramatically improved by combining advanced technologies with traditional drilling techniques. The implementation of more effective drilling technologies integrating microwaves energy may yield substantial improvements in rock excavation as well as in mining processes. In essence, the electromagnetic energy from microwaves is used in weakening the rock ahead of the mechanical rock boring equipment. The hard rock is literally transformed into a soft rock increasing efficiency of the boring equipment and even lending itself amenable to techniques normally only applicable in soft rock conditions. Potentially, all the techniques developed for excavating soft rock such as road headers in mechanized mining or tunnelling machines could become applicable in hard rock conditions such as the basaltic rock used in the applicant’s experiments. This opens very interesting avenues for deep mining applications. In these instances, conventional methods using explosives and large openings are not amenable due to the very high stresses conditions. Mechanized rock breakage in hard rock is not efficient. But combining electromechanical and mechanical energies for such conditions could prove very beneficial.
This development could lead to significant cost savings to the Canadian mining industry, to more energy efficient processes and provide a benefit to an overburdened national energy inventory. The authors have designed a patented rock drilling prototype combining microwaves energy with a conventional drilling unit. But this development opens very promising development avenues in tunnel boring machines design as well as mechanized mining. In this paper preliminary results of rock drilling experiments conducted with the microwave drill will be presented and discussed. Potential extensions of this innovative technique toward tunnel boring, raise boring and mechanized mining applications will be commented.

Keywords: Rock breakage, Tunnel boring, Excavation, Deep Mining, Electromagnetic Energy, Mechanical Energy, Drilling, Rock mechanics, Mechanized mining, Microwaves
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