Rock differentiation using microwave irradiation

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dc.contributor.advisorDowning, B Jen_ZA
dc.contributor.authorMercer, Sean Ren_ZA
dc.date.accessioned2014-11-15T19:35:39Z
dc.date.available2014-11-15T19:35:39Z
dc.date.issued1987en_ZA
dc.descriptionIncludes bibliographical references.en_ZA
dc.description.abstractThis project arose as a result of inefficiencies in the diamond recovery process at Premier Mine. A considerable amount of barren waste rock, gabbro, is mined along with the diamond bearing kimberlite. No automated method exists for separating the kimberlite from the waste rock and a device was required to effect ore sorting on a rock by rock basis. Experimentation with a microwave oven indicated that samples of kimberlite were more attenuative than samples of gabbro. The possibility of using microwave heating for rock differentiation was investigated but was impractical to implement. A study of low power microwave attenuation and reflection measurements was undertaken. Reflection measurements were found to be impractical due to the similar amounts of reflected signal from the different rock types. Microwave signal attenuation through rock samples was studied over a broad frequency spectrum. A detectable difference in signal attenuation was found through the gabbro and kimberlite. The difference in signal attenuation increased with increasing frequency. Different techniques to implement signal attenuation measurements through rock samples were investigated. The passing of rock samples through waveguide structures was found to be impractical in this application. Microwave signal attenuation measurements were successful when rock samples were placed between a transmitting and a receiving antenna. Equipment was designed and constructed with an operating frequency of 35GHz chosen due to the small antenna aperture area and the large attenuation difference at this frequency. Static measurements with this equipment revealed the problems with signal scattering and reflection from some irregularly shaped samples of low loss gabbro. The importance of these phenomenon could only be gauged from dynamic measurements. Dynamic measurements were performed using a laboratory test system with a conveyor belt capable of moving at speeds of up to 5 m/s. It was found that 93% of the kimberlite could be correctly detected whilst rejecting 67% of the gabbro. The system functioned satisfactorily and led to the filing of several patents.en_ZA
dc.identifier.apacitationMercer, S. R. (1987). <i>Rock differentiation using microwave irradiation</i>. (Thesis). University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Electrical Engineering. Retrieved from http://hdl.handle.net/11427/9638en_ZA
dc.identifier.chicagocitationMercer, Sean R. <i>"Rock differentiation using microwave irradiation."</i> Thesis., University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Electrical Engineering, 1987. http://hdl.handle.net/11427/9638en_ZA
dc.identifier.citationMercer, S. 1987. Rock differentiation using microwave irradiation. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Mercer, Sean R AB - This project arose as a result of inefficiencies in the diamond recovery process at Premier Mine. A considerable amount of barren waste rock, gabbro, is mined along with the diamond bearing kimberlite. No automated method exists for separating the kimberlite from the waste rock and a device was required to effect ore sorting on a rock by rock basis. Experimentation with a microwave oven indicated that samples of kimberlite were more attenuative than samples of gabbro. The possibility of using microwave heating for rock differentiation was investigated but was impractical to implement. A study of low power microwave attenuation and reflection measurements was undertaken. Reflection measurements were found to be impractical due to the similar amounts of reflected signal from the different rock types. Microwave signal attenuation through rock samples was studied over a broad frequency spectrum. A detectable difference in signal attenuation was found through the gabbro and kimberlite. The difference in signal attenuation increased with increasing frequency. Different techniques to implement signal attenuation measurements through rock samples were investigated. The passing of rock samples through waveguide structures was found to be impractical in this application. Microwave signal attenuation measurements were successful when rock samples were placed between a transmitting and a receiving antenna. Equipment was designed and constructed with an operating frequency of 35GHz chosen due to the small antenna aperture area and the large attenuation difference at this frequency. Static measurements with this equipment revealed the problems with signal scattering and reflection from some irregularly shaped samples of low loss gabbro. The importance of these phenomenon could only be gauged from dynamic measurements. Dynamic measurements were performed using a laboratory test system with a conveyor belt capable of moving at speeds of up to 5 m/s. It was found that 93% of the kimberlite could be correctly detected whilst rejecting 67% of the gabbro. The system functioned satisfactorily and led to the filing of several patents. DA - 1987 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1987 T1 - Rock differentiation using microwave irradiation TI - Rock differentiation using microwave irradiation UR - http://hdl.handle.net/11427/9638 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/9638
dc.identifier.vancouvercitationMercer SR. Rock differentiation using microwave irradiation. [Thesis]. University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Electrical Engineering, 1987 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/9638en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Electrical Engineeringen_ZA
dc.publisher.facultyFaculty of Engineering and the Built Environment
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherElectrical and Electronic Engineeringen_ZA
dc.titleRock differentiation using microwave irradiationen_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMScen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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