Relative-value, discrimination-factor, and vector-ratio method for defining anomalies in geochemical data

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

C. I. Godwin
Department of Earth, Ocean and Atmospheric Sciences, The University of British Columbia, Vancouver, British Columbia, Canada
and
Godwin Consultants Ltd., Port Moody, British Columbia, Canada

http://dx.doi.org/10.15834/cimj.2016.13
Abstract 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; calculating geologically defined D-factors from R-values; and determining V-ratios. D-factors are the sum of R-values, divided by the number of R-values summed. Based on the analyses selected, D-factors mimic rock or mineral deposit signatures. V-ratios refine interpretations of rock type and vector to orebody locations.
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)
Résumé La méthode de la valeur relative (valeur R), du facteur de discrimination (facteur D) et du rapport de vecteurs (rapport V) (RDVM), fournit un schéma d’interprétation des données géochimiques basé sur les statistiques et les connaissances géologiques et la génétique géologique; ce schéma contribute aux découvertes en exploration géochimique. L’avantage pratique de la RDVM est qu’elle fait la synthèse des caractéristiques géochimiques reliées géologiquement à des découvertes de gisements de minerais en trois étapes : une reclassification des concentrations des éléments au moyen de courbes de probabilité logarithmique en valeurs R; un calcul des facteurs D définis géologiquement à partir des valeurs R et la détermination des rapports V. Les facteurs D sont la somme des valeurs R divisés par le nombre de valeurs R additionnées. Selon les analyses choisies, les facteurs D imitent les signatures de la roche ou des gisements minéraux. Les rapports V peaufinent les interprétations des types de roches et dirigent vers des emplacements de gisements.
Mots-Clé Découverte de gisements minéraux; évaluation géochimique; facteur de discrimination; interprétation basée sur la génétique géologique; méthode basée sur les connaissances géologiques; méthode de la valeur relative (valeur R), du facteur de discrimination (facteur D) et du rapport des vecteurs (rapport V) (RDVM); population anormale; population de fond; probabilité logarithmique
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Publication: CIM Journal
Issue: 2
Volume: 7
Year: 2016
Text
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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 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
Text
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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Summary: 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...
Publication: CIM Journal
Author(s): M. R. P. Snow
Keywords: American Society for Testing and Materials (ASTM), Geotechnical, Ground support, Heat treatment, In-situ, Rock mass rating (RMR), Rockbolts, Steel
Issue: 2
Volume: 7
Year: 2016
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