Designing steel for ground-support applications in underground mines

CIM Journal, Vol. 7, No. 2, 2016

M. R. P. Snow
Queen’s University, Kingston, Ontario, Canada

http://dx.doi.org/10.15834/cimj.2016.10
Abstract This paper outlines geotechnical conditions that commonly exist in underground, hardrock mines and the challenges posed for ground-support steel, specifically rockbolts, used in these environments. A model is proposed whereby the in-situ stress and rock-mass classifications (based on Bieniawski’s rock mass rating) form the basis of determining the desired steel properties of the rockbolts used. Based on the ASTM F432 bolting specification, recommended minimum steel properties are defined for three ranges of in-situ stress levels, each with their own six ranges of RMR values. Heat treatment for the steel can be specified once these minimum steel properties are known.
Keywords: American Society for Testing and Materials (ASTM), Geotechnical, Ground support, Heat treatment, In-situ, Rock mass rating (RMR), Rockbolts, Steel
Résumé Le présent article décrit les conditions géotechniques qui existent fréquemment dans les mines souterraines de roches dures et les défis que cela pose pour le soutien de terrain en acier, plus spécifiquement les boulons d’ancrage utilisés dans ces environnements. Un modèle est proposé dans lequel les contraintes in situ et les classifications de la masse rocheuse (selon la classification de la masse rocheuse de Bieniawski) servent de base pour la détermination des propriétés désirées pour l’acier des boulons d’ancrage utilisés. En se basant sur les spécifications de boulonnage de l’ASTM F432, les propriétés minimales recommandées pour l’acier sont définies pour trois plages de niveaux de contraintes in situ, chacune avec sa propre plage de six valeurs de classification de la masse rocheuse (RMR). Un traitement thermique pour l’acier peut être spécifié une fois que ces propriétés minimales pour l’acier sont connues.
Mots-Clé Acier, American Society for Testing and Materials (ASTM), Classification de la masse rocheuse (RMR), boulons d’ancrage, géotechnique, in situ, soutien de terrain, traitement thermique
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Publication: CIM Journal
Issue: 2
Volume: 7
Year: 2016
Text
Summary: Block caving is the preferred underground mining method to profitably extract massive, low-grade orebodies; however, lack of cave access inhibits understanding the rockmass response to mining, which is needed for safer, more productive operations. Combining large datasets from multiple sources with virtual reality scientific visualization (VRSV) is an alternative method for understanding complex cave behaviour, by providing virtual access to the cave. A customized VRSV module was developed at...
Publication: CIM Journal
Author(s): J. D. Tibbett, F. T. Suorineni, and B. K. Hebblewhite
Keywords: Block caving, Large multiple-source datasets, Time dependency, Virtual reality scientific visualization (VRSV)
Issue: 2
Volume: 7
Year: 2016
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Summary: Some non-flotation chemicals are added to flotation circuits directly and indirectly to control issues such as scaling and dust in other areas of the operations. Since dosage levels are generally not high, a standard laboratory float test may not be able to determine the effect of a specific chemical on the productivity of the flotation circuit. This paper presents a laboratory testing protocol that uses kinetic float studies to test the effect of normal to extreme doses of antiscalant and...
Publication: CIM Journal
Author(s): B. G. Cousins and B. O’Rourke, C. Spence
Keywords: Chemicals, Flotation, Interferences, Kinetics
Issue: 2
Volume: 7
Year: 2016
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Summary: The relative-value (R-value), discrimination-factor (D-factor), and vector-ratio (V-ratio) method (RDVM) provides a geological knowledge-based statistical and geological-genetic interpretation scheme for geochemical data that enhances discovery in geochemical exploration. The practical advantage of RDVM is that it synthesizes geochemical features geologically related to ore-deposit discovery in three steps: reclassifying element concentrations using log-probability plots into R-values;...
Publication: CIM Journal
Author(s): C. I. Godwin
Keywords: Anomalous population; Background population; Discrimination factor; Geochemical evaluation; Geological-genetic interpretation; Geological knowledge–based method; Log probability; Ore-deposit discovery; Relative-value (R-value), discrimination-factor (D-factor), and vector-ratio (V-ratio) method (RDVM)
Issue: 2
Volume: 7
Year: 2016
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Summary: The inverse slope method (ISM) was applied to reinterpret vertical electrical soundings (VES) data from pits at the Al-Sharquieh phosphate mine, in order to demonstrate applicability and suitability of the ISM for interpreting VES data from sedimentary phosphatic environments. The ISM overcomes limitations of the curve matching method and the complexity of lithological sections. The ISM geo-electrical interpretation results correlated well with lithologies of the pits. This method characteriz...
Publication: CIM Journal
Author(s): J. Asfahani
Keywords: Al-Sharquieh mine, Syria; Inverse slope method (ISM); Phosphate; Vertical electrical soundings (VES)
Issue: 2
Volume: 7
Year: 2016
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Summary: Microseismic monitoring provides insight into the location and extent of rock-mass fracturing induced by cave mining, enabling interpretation of the cave profile and validation of predictive numerical models. Source location uncertainties can lead to misinterpretation of the inferred characteristics of the fracture network. One principal source of uncertainty is the velocity model used to invert the location algorithm. Large-scale 3D numerical models of modulus changes across a caved mass can...
Publication: CIM Journal
Author(s): J. M. Reyes-Montes, B. L. Sainsbury, J. R. Andrews, R. P. Young
Keywords: Cave-scale model, Caving, Continuum elastic modulus modelling, Microseismicity, Velocity imaging
Issue: 2
Volume: 7
Year: 2016
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Summary: The St. Lawrence Granite hosts vein-type fluorite mineralization that was mined until 1977. Recent drilling identified a significant fluorite-bearing structure hosted in adjacent meta-sedimentary country rocks. Several phases of vein fill and brecciation indicate there are three phases of fluorite mineralization, of which the later two phases are volumetrically significant. The earliest fluorite is purple and occurs along joint and fracture surfaces, in fault-breccia matrices, and as...
Publication: CIM Journal
Author(s): J. H. Reeves Newspar, B. A. Sparkes, N. Wilson Newspar
Keywords: Burin Peninsula, Fluorite, Fluorspar, Newfoundland, St. Lawrence Granite
Issue: 2
Volume: 7
Year: 2016
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