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A laboratory size solvent extraction apparatus has been constructed, which incorp- orates three stages of countercurrent extraction, followed by two stages of counter- current stripping. The model uses a gravity flow system from one stage to another and air lift pumps to recirculate organic and aqueous phases. A novel pump/mixer system is used to transfer solutions from the mixer compartments to the settler compartments. The model has proven valuable in the teaching of solvent extraction principles.

Jan 1, 1999

By S. Schina

Part of the Imittos Western Peripheral Motorway in Athens is the twin road tunnel in the vicinity of American College, with 20m excavation diameter. In the paper, the environmental and other requirements, the geometry and the geological – geotechnical characteristics of the rock formations in the construction area are given. Information regarding the modeling and analysis methods that are used for the design of the temporary support, the final lining and the wedge and slope stability analysis is described thoroughly. Finally, the results of the analyses are compared with these of measurements and general remarks during the construction of the tunnels.

Jan 1, 2001

By Jean-Marc Simard, Vincent Jourdain, Denis W. Roy

"Seven lithologic units, informally characterized, were recognized in the vicinity of the Montauban orebody. The first five lie in stratigraphic order. From structural bottom to structural top these are: (1) grey composite gneiss; (2) dark grey quartz-biotite gneiss; (3) quartz-biotite-garnet gneiss hosting several calcareous, aluminous and magnesian members and gold mineralization; (4) light grey quartz-muscovite-(sericite)-biotite gneiss; and (5) metabasafts. The last two intrude the sequence: (6) amphibolite dykes and (7) pegmatite veins. The orebody lies on the inverted limb of an overturned synform verging to the west with the metabasafts marking the core of the fold. As the foliation is folded, this fold is attributed to deformation ""D2""; deformation ""DI"" being responsible for the formation of the foliation. A late brittle deformation developed shear zones with probable strike-slip motions. The refined stratigraphy and the identification of the structural position of the orebody provide new tools for regional interpretation and prospecting.RESUMESept unités lithologiques ont été définies informeffement à proximité du gisement de Montauban. Les cinq premieres reposent en ordre stratigraphique; ce sont de la base au sommet structural: (1) le ""gneiss mixte gris""; (2) le gneiss gris forcé à quartz biotite; (3) le gneiss a quartz-biotite-grenat comprenant plusieurs membres calcareux, alumineux et magnésiens ainsi que la minéralisation aurifère; (4) le gneiss gris clair à quartz muscovite- Isericitel-biotite; et (5) les métabasaltes. Les deux autres unites sont intrusives dans la sequence: (6) les dykes d ‘amphibolite et (7) les veines de pegmatite. Le gisement se sitlie sur le flanc inverse d'un synforme déverse vers I' ouest dont les métabasaltes occuperaient le cœur. Comm e la foliation est plissée, ce pli est considère appartenir d la deformation ""D2""; la deformat ion ""DI"" etant responsable de la formation de lafoliation. Une deformation cassante tardive se traduit par des zones de cisaillement, d rejet apparemment directionnel. Cette stratigraphie plus précisé et l'indentification de la position structurale du gisement fournissent de nouveaux omits de prospection et d'interprétation regionalé."

Jan 1, 1987

By W. C. Lacy

Stratabound copper ore bodies in thick Proterozoic metamorphosed sedimentary and volcanic rocks at the Tong Kuang Yu Mine in southern Shanxi Province of China were considered as possibly being amenable to block cave mining. Initial evaluation of caving characteristics was based upon old calyx drilling records, limited underground mining experience and geological mapping, a few diamond drill holes and measurements in surface subsidence features. Classification and mapping distribution of rock quality types aided in mine design, prediction of fragment sizing and explosive requirements, cave assist and ground support requirements. Comparison is made between early feasibility predictions and actual mine experience.

Jan 1, 1989

By M. Abzalov

"Control of analytical data quality is usually referred to in the mining industry as Quality Assurance and Quality Control (QAQC), and involves the monitoring of sample quality and quantification of analytical accuracy and precision. QAQC procedures normally involve using sample duplicates and specially prepared standards whose grade is known. Numerous case studies indicate that reliable control of sample precision is achieved by using approximately 5% to 10% of field duplicates and 3% to 5% of pulp duplicates. These duplicate samples should be prepared and analyzed in the primary laboratory.Bias in the analytical results can be identified by inclusion of 3% to 5% of the standard in each sample batch. Several different standards are used, with values spanning the practical range of grades in the actual samples. A blank (a sample in which the concentration of metal of interest is below detection limit) should also be included. Standard samples alone cannot identify biases introduced during sample preparation, and therefore approximately 5% of the duplicate samples (coarse rejects and pulp) should be processed and assayed at another, external, reputable laboratory.This paper discusses techniques used for estimation of errors in precision and accuracy, and overviews diagnostic tools. It is shown that one of the most commonly used methods, the Thompson-Howarth technique, produces consistently lower results than other methods. These results reflect the nature of this method, which relies on the assumption of a normally distributed error, and thus produces biased results when errors have a skewed distribution. This study concurs with the suggestion of Stanley and Lawie (2007: Exploration and Mining Geology, v. 16, p. 265-274) to use the average coefficient of variation (CVAVR(%)) as the universal measure of relative precision error in mine geology applications: Le contrôle de la qualité des données analytiques est habituellement désigné sous l’appellation d’Assurance et Contrôle de la Qualité (ACQ), elle implique le suivi de la qualité des échan¬tillons et la quantification de la reproductibilité et la précision analytiques. Les procédures des pro¬grammes d’ACQ impliquent habituellement l’usage de duplicata et de standards analytiques dont la teneur est connue. Plusieurs études de cas indiquent qu’une bonne fiabilité du contrôle de la précision des échantillons est atteinte par l’usage de 5% à 10% de doublons sur le terrain et de 3% à 5% de doublons de pulpe. Ces duplicata devraient être préparés et analysés au laboratoire principal.Un biais des résultats analytiques peut être identifié par l’inclusion de 3% à 5% d’échantillons standard dans chaque envoi d’échantillons. Plusieurs standards sont utilisés, avec des valeurs couvrant l’étendue des teneurs habituellement rencontrées dans des échantillons réels. Un blanc (un échantillon dans lequel la concentration d’un métal donné est sous la limite de détection) devrait aussi être inclus. L’emploi exclusif d’échantillons standards ne permet pas l’identification de biais résultant de la préparation des échantillons, de telle sorte qu’environ 5% des duplicata (rejets grossiers et pulpes) devrait être traités a un autre laboratoire indépendant et fiable.Cet article passe en revue les techniques utilisées pour évaluer l’erreur liée à la précision et a la reproductibilité, et effectue aussi un survol de divers outils diagnostiques. Il ressort de cet examen qu’une des techniques les plus fréquemment utilisées, la méthode Thompson-Howarth, fournit des estimés systémati¬quement inférieurs à ceux provenant des autres méthodes. Ces résultats sont un reflet de la nature de cette méthode, laquelle assume une distribution normale de l’erreur, biaisant ainsi les résultats lorsque l’erreur présente une distribution asymétrique. La présente étude recommande de privilégier l’usage du coefficient moyen de variation (CVAVR(%)) en tant que mesure universelle de la précision relative de l’erreu"

Jan 1, 2008

By Cordner G. D

Titanium is not yet being produced on a commercial scale despite the facts that it has some impressive properties, and that it occurs very abundantly in easily-mined, highgrade oxide ores. One important reason for this is that the excellent mechanical properties of the metal were not widely recognised and appreciated until about twenty years ago.Another factor which has tended to retard progress in titanium metallurgy has been the realization that the oxide minerals of titanium are very stable; in other words, considerable energy has to be expended to reduce the oxide to metal. Table 1 presents the minimum energies which would have to be expended to produce one ton of each of the metals, aluminium, magnesium, titanium and iron from their respective oxides under theoretically ideal conditions at normal temperature and pressure. At higher temperatures, the minimum energy requirements are different, but the values for the various metals still fall in the same order as indicated in Table 1.In actual fact, the energy consumption in the case of any particular metal is higher than the ideal value by an amount which can be determined only by' the results of plant practice. The only general conclusion that can be drawn from the data in Table 1 is that it might eventually prove...

Jan 1, 1950

By Robert C. Merritt

Laboratory amenability studies as well as a pilot heap-leaching investigation of low-grade sandstone uranium ores from Wyoming, New Mexico, and Colorado are described. Sulfuric acid heap leaching with oxidation, for 120 days, extracted up to 98 percent, 90 percent, and 79 percent U308 from Wyoming, New Mexico, and Colorado ores, respectively.

Jan 1, 1976

By R. Romano

Some topics, which difficult the effective use of RMR for dam foundations, are reviewed and a new geomechanics classification system, DMR (Dam Mass Rating), is proposed -as an adaptation of RMR- giving guidelines for several practical aspects in dam engineering and appraisal of dam foundation. On revise quelques problems qui ont fait difficile l’application du RMR pour les fondations des barrages. On propose un nouveau classification système, DMR (Dam Mass Rating)-comme un désarroi du RMR-qui donne recommendations pour quelques problèmes pratiques dans le projet et construction des barrages, et de ses fondations. Es werden einige die praxisgerechte Nutzung des RMR (Rock mass Rating) erschwerende Themen betrachtet und ein neues Geomechanisches Einteilungssystem, das DMR (Dam Mass Rating), eine Anpassung des RMR, vorgeschlagen. Daraus resultieren neue Richtlinien für verschiedene praktische Aspekte beim Dammbau und bei der Beurteilung von Dammunterbauten

Jan 1, 2003

By Harushige Kusumi, Yuzuru Ashida, Toshiki Watanabe, Toshifumi Matsuoka

ABSTRACT: The technique of various kinds of numerical analysis offered remarkable results to explication of many rock mechanical phenomena. These techniques regarded a rock stratum as a continuum body and solved the governing equation of continuum mechanics by using finite differ-ence method, finite element method and/or others. Using numerical analysis based on continuum mechanics, however, the simulations of destruction phenomena caused by elastic waves and on the other hand, the elastic wave propagation which generated by fracturing events are quite difficult. In this paper, we express a rock stratum by a granular body model and develop a simulation tech-nique can simulate both wave phenomena and destruction phenomena at once. The DEM (discrete element method) simulation results are compared with finite difference solutions of elastic wave equation. Furthermore, we simulate Hopkinson effect by this proposed method. Hopkinson effect is famous as a destruction phenomenon caused by elastic wave propagation. ABRISS: In dieser Studie drücken wird eine Felsschicht durch ein Granularkörpermodell aus und entwickeln eine Simulationstechnik, die sowohl Wellenphänomene als auch Zerstörungsphänomene simulieren kann. Die Ergebnisse der Simulation mit DEM (Diskrete-Elemente-Methode) werden mit denen der Finit-Differenz-Lösung von Gleichungen elastischer Wellen verglichen. Desweiteren simulierten wir den Hopkinson-Effekt mit dieser vorgeschlagenen Methode. Der Hopkinson-Effekt ist als Zerstörungsphänomen berühmt, verursacht durch Fortpflanzung elastischer Wellen. RESUME: Dans cette étude, nous exprimons un lit de roches par un modèle à corps granulaire et développons une technique, permettant de simuler d'un coup le phénomène des ondes et le phé-nomène de destruction. Les résultats de la simulation DEM (méthode d'éléments discrets) sont comparés aux solutions à différence finie de l'équation d'ondes élastiques. En outre, nous simulons l'effet d'Hopkinson par la méthode proposée. L'effet d'Hopkinson est connu comme phénomène de destruction, causé par la propagation d'ondes élastiques.

Jan 1, 2003

By Roy F. Abernethy

All samples tested showed some loss of heating value for the 5-month period under all 4 storage conditions. The losses increased as the time of storage increased, with the pan-storage samples showing somewhat greater losses than those in cans. The individual daily analyses for the first 2 weeks and the analyses every other day for the third and fourth weeks of storage vary within the approximate tolerance of the test for heating value. During the first 2 months of storage the changes in heating values were not Significant for the samples from Pennsylvania, Indiana, and Colorado. The Ohio coal indicated some loss by the end of I month, which increased to a value measurable with certainty by the end of 2 months. These data show that (1) small changes may occur even to samples in closed cans and (2) the laboratory sample should be handled as expeditiously as is practical until the analysis is completed. The statement by the ASTM that "If the B.t.u. determination is an important consideration in the sale of coal, the time elapsed between sampling and analysis shall not exceed 30 days,"3/ is quite adequate for 3 of the 4 coals tested. The change in the Ohio coal stored for 30 days is merely indicated and could not be determined with certainty by the techniques normally employed. The data on free-swelling indexes determined on can samples, after 30° C. air drying, show that only the Indiana coal lost more than one unit in free-swelling index number in 120 days. No significant changes were observed with the samples from Pennsylvania, Ohio, and Colorado in the 5-month period.

Jan 1, 1958

This paper contains an account of some creep tests on electrolytic lead and some of its alloys. The stresses used in determining creep were 500, 350, and 200 lb. per sq.' in. The alloys contained silver, bismuth, tellurium, antimony and zinc respectively. All were castin vacuo, and tested "as rolled." Tests were done also on electrolytic lead which had been cast in air.The electrolytic lead contained 0.0005% total impurities.The preparation and vacuum casting of this lead have been described in a previous paper in this series. The preparation of the alloys, and the air casting of the electrolytic lead, are described in the next section.EXPERIMENTAL PROCEDURE.Every effort was made to keep the vacuum-cast specimens from contact with the atmosphere throughout their history.The ingots were stored eIther in a vacuum desiccator or immersed in heavy oil. The creep specimens were coated with vaseline except during rolling, etching and photography, which involved exposure to the atmosphere for about 45 minutes all told.It is not claimed that vaseline is a perfect shield against the intrusion of atmospheric gases. Possibly during the months that some tests were in progress the gases diffused through the vaseline and gained a limited access to the lead.Nevertheless, the use of vaseline gave protection that brought the tests nearer the ideal at which the author aimed, *Research Fellow, Dept. of Metallurgy, University of Melbourne.

Jan 1, 1936

By Otto Sandovel Zea

El compromiso de minería perfecta se limita no solo a la preservación del medio ambiente, sino a la prevención de riesgos por desprendimiento de rocas y aplastamiento en el interior de la mina. En ese sentido, el presente texto señala la factibilidad de minar a sección plena todos los tajeos a través de la simulación de las condiciones más favorables y desfavorables de la mina, determinando como la alternativa más viable la bóveda en arco. Dicha estructura otorga estabilidad a las labores de minado -en tanto da sostenimiento activo a través del (Shotcrete SFR y Pernos Hydrabolt), así como desarrolla mayor productividad y menores niveles de riesgo por desprendimiento de rocas, menores grados de sobre excavación y genera de vibraciones al haber implementado la voladura de Pre-corte en sus labores.

Sep 12, 2011

By W Donovan

Concern exists about the potential release of metals from the proposed mining operation at Martha Hill to the Ohinemuri River. Speculation on possible impacts is fuelled by the dearth of published data on existing metal levels not only for this river system but for streams throughout the Coromandel. At first sight this lack of data is surprising given the apparent interest in this subject and the fact that future mining activity in this region has been a possibility since at least 1979. That such a situation has arisen is not altogether unexpected given the difficulties faced by various organisations, including the mining industry, in determining metal levels which are generally acknowledged to be low. This paper presents data for a number of stations in the vicinity of the proposed operation; it explains the analytical procedures which were adopted and the rationale for them and relates the information which has been obtained to water quality criteria.

Jan 1, 1986

By Marlion T. McQuinn

This paper will discuss the design, construction, and performance of the support of excavation on the Dulles East and West Automated People Mover Tunnels and Station projects. The elements of the system included drilled soil nails and rock anchors with reinforced shotcrete to the excavated face. We will discuss the geotechnical characteristics, design and construction considerations, loading criteria, construction techniques, schedule constraints, and performance of the support of excavation system. In consideration of the conference theme, there will be a discussion of the application of the real-time instrumentation monitoring program. The project team worked to design and install approximately 710,000 square feet of shotcrete and 19,000 soil nails/rock anchors as well as excavate over 720,000 cubic yards of rock materials within 15 months and in such a manner as to minimize the disruption to airport passengers and operations.

Jan 1, 2006

By T. Rasmussen, T. G. Jørgensen, T. Fischer, R. K. McLimans, C. Knudsen, D. Frei

Ilmenite-bearing paleo-beach deposits were discovered in Jylland, Denmark using a combination of Ground Penetrating Radar (GPR), portable X-ray fluorescence (XMET), bulk XRF analyses, Computer Controlled Scanning Electron Microscopy (CCSEM), and wire line logging. The Miocene-age paleo-beach deposits are located below a thin Quaternary cover in a region of very moderate relief and essentially no outcrop demanding unique approaches in exploration. Initially, an isopach map of the Quaternary is prepared from existing water well data. A geological model for likely occurrence of Miocene paleo-beach deposits is generated and the coincidence of thin Quaternary cover and potential paleo-beach deposits define targets for detailed exploration. The defined targets are traversed with GPR to identify paleo-beach structures which are then used to define a drilling program. This methodology located a paleo-barrier island at the Vorslunde location with more than 10% ilmenite in the sand. During the drilling process, the TiO2 and heavy mineral contents of the sand were logged every meter with a portable XRF unit (XMET) and subsequently calibrated more accurately by comparison to bulk XRF and CCSEM analyses for selected samples. The bulk XRF data also provided more complete compositional information. Insitu determination of geology, heavy mineral abundance, and corroboration of the XRF logging was done using wire line logs, a combination of spectral gamma and induction conductivity logs. Detailed characteristics (abundance, grain size, shape) and chemical composition of minerals was determined by the GEUS CCSEM methodology (Frei et al, this vol.). The average weight percent TiO2 for all Ti-minerals is 62%, 60% excluding rutile. That elevated TiO2 content (>> ilmenite stoichiometric value, ca. 50 %) indicates that ilmenite experienced an iron-leaching environment. The source of the sand deposit was investigated by dating contained zircon. The results show that the likely sources of zircon are in southern Norway and southwestern Sweden with common zircon ages of ca 1100 Ma. and 1500 Ma.

Jan 1, 2005

By Michel C. Frippel

This section of the Minerals Yearbook reviews the minerals industries of 29 countries: the 12 nations of the European Community (Belgium, France, the Federal Republic of Germany (FRG), Italy, Greece, the Netherlands, Denmark/Greenland, Spain, Portugal, Luxembourg, the United Kingdom, and Ireland); 6 of the 7 nations of the European Free Trade Association (Sweden, Nor-way, Finland, Iceland, Austria, and Switzerland); Malta; the 8 Centrally Planned Economies of Eastern Europe (the German Democratic Republic (GDR), Poland, Yugoslavia, Albania, Hungary, Czechoslovakia, Romania, and Bulgaria); and the U.S.S.R. Western Europe Western Europe [loosely defined to include the 12 nations of the European Com-munity (EC) and the 7 nations of the European Free Trade Association (EFTA)] is the single largest trading area and consumer of raw materials in the world. If Western Europe was at one time an important mining sector, it has now increasingly relegated the role of supplying minerals for its minerals processing industry to its ex-colonies in North and South America, Africa, and Australia. In this regard, Western Europe is the most important determinant of raw materials consumption (and thus raw materials production). There is an important reason for this since Western Europe lies somewhere between Japan at one extreme and the United States and the U.S.S.R. at the other extreme as regards the availability of natural resources.

Jan 1, 1992

By Lee Nichols

Convergent Bitumen Recovery Context of discussion It should be noted that the CBR process is a conceptual bitumen recovery feed methodology, designed to provide supplemental bitumen to the oil sand operations of Northern Alberta. To date the following have beencompleted. ?Bench Scale testing. ?Peer group brainstorming. ?Energy Balance ?Confidentiality agreements have been signed with several companies Discussions are ongoing with industry and although conceptual atthis stage the process holds significant promise.

May 1, 2007

By K Pery, J Leahy

Established metallurgical plants operate in a complex environment of interdependent drivers including technology change, operating and maintenance practice, evolving markets, HSEC requirements, statutory and plant requirements, personnel turnover, ore supply, and financial conditions, to name a few. A successful optimisation program should comprehend these factors and drive towards not only lower operating costs, but also higher rates of return for a given level of investment. Optimisation programs have the potential for very high rates of return on capital that Greenfield projects rarely have. This paper presents a robust strategy and methodology for plant optimisation initiatives as well as a case study of how it was implemented at the QNI Yabulu refinery in Queensland, Australia by an integrated team of researchers, engineers and operators. The methodology is premised on the fact that nobody knows the production asset as well as the current operating team. It covers the optimisation process from ideas generation, various stages of selection against the agreed criteria, development, including testwork, funding approval and implementation. It highlights the benefits in the use of integrated teams, the establishment of a sound project basis, and a diligent, phased approach.

Jan 1, 2004

By C. Musingwini

Traditionally, mineral reserves management at most underground mines in Zimbabwe focus on maintaining large mineral reserves so that the time between development and production is as long as possible. Historical data at Shabanie mine, a Zimbabwean sub-level caving underground mining operation, confirms this practice. However, the high cost of underground development means that the luxury of large buffer mineral reserves cannot be justified. Furthermore significant increases in the costs of production, exacerbated by the current unfavourable economic climate, make the wisdom of extending development workings well ahead of use questionable. Poor ground conditions at Shabanie mine, mean that some development ends have to be re-mined two or three times due to partial or complete closure between the time they are mined and the time they are utilized. In order to reduce the inordinately high support costs associated with closure of development ends a new ?just-in-time? (JIT) approach that provides development ends as and when they are needed, has been adopted. Accordingly a model to determine an appropriate ?just-in-time? rate of development has been created. The JIT development model indicated that the mine could reduce development rates from 330 m/month in 2001, to 160 m/month in 2002 and achieve savings of about 50% on annual support costs, but still assure customers of a long-term product supply. The mine accepted the model in November 2001 and began implementing it in 2002. Results of the implementation will be reviewed in 2003.

Jan 1, 2003

By F. D. Ford, Z. Dai, A. Byers

Manitoba Mining and Milling operations consist of three underground mines (Thompson T1, T3 and Birchtree), feeding the Thompson Mill. Three years ago, a collaborative effort involving Mines Exploration, Mines Project Development Group, Mill Technical Services and Vale Base Metals Technical Excellence Center was initiated to establish and verify the cause of high variability in concentrate quality and Ni recovery at the Thompson Mill. One outcome of this work was a program to systematically characterize the mineralogy and metallurgical performance of current and future orebodies feeding the mill. Mineralogy results show that high value enabling ores typically have a high pentlandite to pyrrhotite ratio and benign silicate mineralogy (mostly quartz and feldspar from sedimentary host rocks), while metallurgically challenging ores contain some combination of pyrite and/or hexagonal (non-magnetic) pyrrhotite and/or elevated quantities of talc (with associated carbonates) derived from altered ultramafic host rocks. The metallurgical performance of these two ore types has been simulated by an Excel particle flotation model, which calculates the relative floatability of particles based on the particle’s mineral composition and mineral locking determined from MLA images. The relationship between these mineral properties measured by MLA and metallurgical performance was established using 13 monthly composite samples from Thompson Mill. The model was then validated with results of laboratory flotation experiments on individual orebodies submitted for evaluation. The validated model can be used to predict plant metallurgical performance based on individual ore bodies feeding the mill. Individual orebody’s grade-recovery curves are assumed to be additive, and can be weighted in proportion to the mill feed to predict mill recovery over the same time period. The ore mixing can be done with a simple Excel spreadsheet and comes with a graphical output for easy visualization of the resulting grade-recovery curve.

Jan 1, 2015