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Dorion J.F.,Niobec Inc. | Hadjigeorgiou J.,University of Toronto
Transactions of the Institutions of Mining and Metallurgy, Section A: Mining Technology | Year: 2014

The selection and design of rock support systems rarely takes into explicit consideration the susceptibility of the systems to corrosion. The loss in capacity associated with the corrosion of support systems can be a major safety and economic concern in underground hard rock mines. This paper reports on the influence of atmospheric, aqueous and microbiological corrosion on the performance of support systems in several hard rock underground mines. In situ observations were complemented by laboratory investigations aiming to quantify the potential in loss of capacity of the installed support systems. A methodology is proposed to contribute to the selection and design of support systems in corrosive environments. © 2014 Australian Centre for Geomechanics, The University of Western Australia Published by Maney on behalf of the Institute of Materials, Minerals and Mining and The AusIMM. Source


Hadjigeorgiou J.,University of Toronto | Dorion J.F.,Niobec Inc. | Ghali E.,Laval University
46th US Rock Mechanics / Geomechanics Symposium 2012 | Year: 2012

This paper presents the results from a 5 year laboratory and in situ investigation into the cause of corrosivity of rock support systems in underground hard rock mines. Long term in situ monitoring of corrosion was complemented by controlled investigations in corrosion chambers. During site visits, samples of corroded support units were collected from several mines and subsequently analyzed using S.E.M. and photomicrography. A series of controlled experiments in the corrosion chambers qualified and quantified the influence of minerals and rock deposits on the corrosion rate of steel and rock support. Copyright 2012 ARMA, American Rock Mechanics Association. Source


Dorion J.-F.,Niobec Inc. | Hosseini Z.,ESG Solutions
47th US Rock Mechanics / Geomechanics Symposium 2013 | Year: 2013

The Niobec underground niobium mine is located twenty-five kilometres northwest of Ville de Saguenay (Chicoutimi), within the limits of the municipality of Saint-Honoré, Québec. The mine is North America's only source of pyrochlore, the primary niobium ore. All of Niobec ore is extracted by bulk open stope mining with no fill. A mining throughput rate of 10Mtpy is expected with the future block caving method. The life-span of the mine is estimated at about 40 years with the known mineral resource. Some seismic events have occurred in the last number of years. Most of these events occurred in pillars between open stopes or directly in open stopes. Damage from these events has included small rock projections, raveling and fractures. As Niobec has no seismic detection system in place, the epicenter location of each event has been difficult to determine. The design of a seismic system was undertaken in the summer of 2012. Niobec will be able to monitor seismic activity for the current open stope mining operator as well as for the future block caving method by strategically placing the equipment in existing openings above any planned undercuts for the progression of the caves. Copyright 2013 ARMA, American Rock Mechanics Association. Source


Chehreh Chelgani S.,University of Western Ontario | Hart B.,University of Western Ontario | Marois J.,Niobec Inc. | Ourriban M.,Niobec Inc.
Minerals Engineering | Year: 2012

Time of flight secondary ion mass spectrometry (TOF-SIMS) was used to analyse the surface of two different types of pyrochlore, high Fe pyrochlore and low Fe pyrochlore, from Niobec Saint-Honore mine deposit. Pyrochlore grains were analysed in order to identify a potential relationship between pyrochlore matrix composition, the corresponding surface expression and the related effect on cationic collector adsorption. TOF-SIMS analyses of pyrochlore surfaces from a conditioning test show that the species indicative of the cationic collector, favour the surface of Fe poor pyrochlore relative to the Fe rich variety. Lower collector signals on the surface of the Fe-pyrochlore are matched by higher relative intensities of Fe, OH, O and FeOH. The TOF-SIMS results illustrate a negative relationship between a cationic collector adsorption and the presence of Fe and Fe oxidation species on the surface of pyrochlore grains, and supports previous work which identified a negative correlation between matrix Fe content and pyrochlore floatability. The surface analysis illustrates the link between pyrochlore matrix chemistry, the expression of surface species and their effect on collector adsorption. © 2012 Elsevier Ltd. All rights reserved. Source


Chehreh Chelgani S.,University of Western Ontario | Hart B.,University of Western Ontario | Marois J.,Niobec Inc. | Ourriban M.,Niobec Inc.
Minerals Engineering | Year: 2013

The matrix composition and surface chemistry of high iron pyrochlore (Fe pyrochlore) grains from Niobec (St-Horone carbonatite deposit) were analyzed, in order to identify a potential relationship between Fe pyrochlore matrix composition and the related effect on cationic collector adsorption (tallow diamine). SEM-EDX analyses indicate compositional zoning in the structure Fe pyrochlores. TOF-SIMS was used to analyse the surface of different compositional zones of Fe pyrochlore, in order to identify their related effects on tallow diamine adsorption. Surface analyses of high and low iron zones of treated Fe pyrochlore show that species indicative of the collector favour the regions of low iron content The low iron areas also show a lower relative proportion of species indicative of oxidation. This study identifies the link between Fe pyrochlore compositional zoning, surface oxidation and, area selective collector loading. © 2013 Elsevier Ltd. All rights reserved. Source

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