About the 1996 TMS Annual Meeting: Wednesday Morning Sessions (February 7)

PROCESS MINERALOGY II: Image Analysis

Sponsored by: EPD Process Mineralogy Committee

Program Organizer: Dr. W. Petruk, CANMET, Natural Resources Canada, 555 Booth St., Ottawa, Ontario Canada K1A 0G1

Wednesday, AM Room: A14-15

February 7, 1996 Location: Anaheim Convention Center

Session Chairperson: William Petruk, CANMET, Department of Natural Resources Canada, 555 Booth St., Ottawa, Ontario, Canada K1A 0G1

8:30 am

TECHNIQUES FOR MEASURING MINERAL LIBERATIONS BY IMAGE ANALYSIS: W. Petruk, R. Lastra, CANMET, Department of Natural Resources Canada, 555 Booth St., Ottawa, Ontario, Canada K1A 0G1

Several image analysis techniques are used to measure mineral liberations observed in polished sections of crushed ores. The techniques were compared to determine whether the same results are obtained by each, and to establish a base for developing a standard technique for measuring mineral liberations. The simplest and least valuable technique involves separating images of liberated grains from images of unliberated grains and measuring areal fractions coverd by grains in each occurrence. A second technique involves measuring the areal fraction of mineral in each particle and classifying the particles according to areal fraction of mineral in the particle. A third technique insoles measuring the areal fractions of all minerals in each particle and calculating (using standard S.G.) the weight fractions of the minerals in the particles. The resulting data are classified in the same manner as for the second technique, but can be readily correlated to assays.

9:00 am

MULTISPECTRAL IMAGE BASED APPROACH APPLIED TO INDUSTRIAL ORE MODELLING: MINERALS IDENTIFICATION AND LIBERATION: G. Bonifazi, Dipartimento di Ingegneria Chimica, dei Materiali, delle Materie Prime e Metallurgia, Universita' Degli Studi di Roma "La Sapienza", Via Eudossiana, 18-00184 Roma, Italy

The possibility of recognizing different mineral species in an ore by an imaging multispectral approach is examined. The procedure involves acquiring microscopical optical images from polished and/or thin sections and applying new segmentation strategies to correctly identify mineral species which are not easily identified by classical B&W image analysis techniques. The main aim of this paper is to introduce some of the new techniques and to stimulate the use of such procedures in the field of applied mineralogy and mineral processing. The adoption of these procedures, would in many cases contribute to better identification of the minerals, permit a better and more accurate quantitative characterization of mineralogical textures and consequent better set up of the further beneficiation strategies to apply to the ore.

9:30 am

A DIGITAL MULTISPECTRAL APPROACH APPLIED TO CHARACTERIZE A SWEDISH WOLLASTONITE ORE AND THE RESULTING PRODUCTS OF BENEFICIATION: Girolamo Belardi, Roberto Gorga, Istituto per il Trattamento dei Minerali Consiglio Nazionale delle Ricerche, Via Bolognola, 7-00138 Roma, Italy; Guiseppe Bonifazi, Dipartimento di Ingegneria Chimica, dei Materiali, delle Materie Prime e Metallurgia, Universita' Degli Studi di Roma "La Sapienza", Via Eudossiana, 18-00184 Roma, Italy

Minerographic and petrochemical research was carried out on a wollastonite ore from Sweden to establish a correlation between ore mineralogy and petrographic characteristics and the resulting products of beneficiation. A structural and textural characterization of the ore was numerically developed, with emphasis on morphological and morphometric features of the products according to their mineral compositions. All the procedures tested and developed were multispectral digital image based. Reflected and transmitted light microscopy images were utilized. The results can be applied to assess future strategies for designing beneficiation processes, involving similar ores.

10:00 am

A COMPUTER DESIGN APPROACH TO TOPOLOGICALLY CHARACTERIZE AND MODEL A HYDROTHERMAL SULPHIDE VEIN DEPOSIT (JALES, VILA REAL, NORTHERN PORTUGAL): G. Bonifazi, Dipartimento di Ingegneria Chimica, dei Materiali, delle Materie Prime e Metallurgia, Universita' Degli Studi di Roma "La Sapienza", Via Eudossiana, 18-00184 Roma, Italy; S. Serranti, Dipartimento di Scienze della terra, Universita' Degli Studi di Roma "La Sapienza", P. le Aldo Moro 5, 00185 Roma, Italy

A digital procedure has been developed and discussed in order to identify, recognize and characterize mineral associations and textural properties of a sulphide deposit containing electrum and gold. The deposit is located in the vila Real region in northern Portugal. A computerized full color image analysis system was used to define structural and textural characteristics of the ore, with particular reference to electrum distribution. The procedures were based on a combined use of reflected and transmitted light microscopy techniques. All the analyses and determinations were carried out in order to obtain detailed information for the further beneficiation processes.