The geotechnical characterisation and stability analysis of BHP Billiton's Cannington Mine paste fill

BHP Billiton's Cannington mine is a silver-lead-zinc mine located in North West Queensland, which utilizes post-placed backfill technology in tailings disposal. The backfill is known as paste fill. Paste fill is simply mine tailings, with typical effective grain size of 5 μm, mixed with a small percentage of cement binder. As mine stopes are removed, the paste fill is used to backfill the empty space. Paste fill provides substantial benefits to mining operations including an effective means of tailings disposal, improvement of local and regional rock stability, greater ore recovery and greatly reduced environmental impacts. The studies undertaken as part of this dissertation has included extensive laboratory testing to study the geotechnical behaviour of paste fill. The testing programme included direct shear, triaxial, UCS in addition to the index property tests. These were prepared and cast in the laboratory and cured over different times to include short, medium and long term properties. The study period ranged from less than 24 hours to one year. Additional in-situ testing was conducted at Cannington mine with James Cook Universities' dynamic cone penetrometer to identify the variation of strength with depth. Additional in-situ samples were taken and tested, with the results compared to the laboratory prepared samples. FLAC³ᴰ was used to study the stress development in paste, taking into account the geometric properties of the stope and material properties of the paste fill. A sensitivity analysis was done on the geometry and material properties of the paste to measure the effect on stress development. Artificial neural networks were used as a predictive tool to tie all the outputs from the geotechnical characterisation phase and stress modelling phases. By combining the two phases of the study an integrated model for the prediction and optimisation of the cement content in the backfill masses was achieved. The results of which have been presented within the findings. The stability of fill barricades was also investigated and a relationship between the horizontal stress and the stope geometry, drive location and fill rate developed.

Name dc:type.qualificationname

phd

Level dc:type.qualificationlevel

doctoral

Grantor dc:publisher.institution

James Cook University

Year dc:date.issued

2004

Author dc:creator

• Rankine, Rudd McAuslan

Language dc:language

en

Repository record dc:identifier.uri

https://researchonline.jcu.edu.au/1260/6/1260-rankine-2004-pastec-program.xlsm

OAI record oai:identifier

https://researchonline.jcu.edu.au/cgi/oai2?verb=GetRecord&metadataPrefix=uketd_dc&identifier=oai%3Aresearchonline.jcu.edu.au%3A1260