Search Documents

By S. A. Bortz

This report presents the results of an extensive laboratory testing program to determine the physical properties of shotcrete including the use of fast-set agents, controlled set cements, and both wet and dry shotcreting equipment. Shotcrete was placed under simulated field conditions using the dry and wet processes. Mechanical properties obtained for accelerated and nonaccelerated shotcretes include compressive, flexural, and shear strength, elastic modulus and Poisson's ratio, and shear and tensile properties of shotcrete bonded to coal, sandstone, and shale. Physical properties measured were unit weight and permeability to methane gas. The data show that rapid setting shotcrete has the potential for improved coal mine ground control. There is no clear evidence that either wet or dry process shotcrete is superior to the other; however, indications are that regulated set cement is preferred to cement containing fast-setting admixtures.

Jan 1, 1973

1. Domestic Production and Use: In 1982, 13 companies operated 30 primary aluminum reduction plants, with 3 firms accounting for 55% of production. Washington, Oregon, and Montana accounted for 34% of the production; Texas, Louisiana, Missouri, and Arkansas 18%; Tennessee, Alabama, South Carolina, and North Carolina 14%; other central and eastern States 34%. Based on published producer prices, output of primary metal in 1982 was valued at over $5.5 billion. Aluminum consumption by 25,000 firms was centered in the East Central United States. Packaging accounted for an estimated 39% of domestic consumption in 1982, transportation 20%, building 14%, electrical 8%, consumer durables 8%, and other uses 11%.

Jan 1, 1983

Particles of a complex nickel sulphide concentrate (containing pyrite, pyrrhotite, pentIandite, and violarite as the major mineralogical constituents) were entrained in a stream of hot gas the temperature of which was varied from 500 to -1000°C. Chemical analysis of the particulates collected from the furnace was used to detect the rapid change in sulphur content which accompanied the ignition temperature jump. X-ray diffraction analysis was used to characterize the oxidized material.These techniques showed that ignition was dependent on the mineralogical composition and occurred over the temperature range 500-900°C. Pyrite ignited first in the range 500-600°C; pyrrhotite was the least reactivemineral and required temperatures in excess of 800°C for ignition. The nickel minerals <pentIandite and violarite decomposed before ignition and ignited at temperatures intermediate to those required for the pyrite and pyrrhotite. The ignition temperature for the pyrite was found to be independent of particle size and concentration of oxygen in the atmosphere.Ignition temperatures determined by the simulated flash smelting method were compared with the results of differential thermal analysis (DTA) measurements performed on the same concentrate. Temperaturesdetermined in the DTA test as corresponding to the start of exothermic activity were shown to be at least 100°C below those determined by the simulation test.

Jan 1, 1978

By Aline Miranda Pessoa Passagli

No projeto da usina da Vallourec & Sumitomo Tubos do Brasil (VSB), em Jeceaba – MG está contemplado um circuito de preparação de carga para atender dois altos-fornos de 350 m³ de volume útil. Realizaram-se algumas etapas de testes com carga que possibilitaram a verificação da capacidade real dos equipamentos e a eficiência de peneiramento das matérias-primas. Foram também realizados testes de simulação da amostragem e ensaios físicos das matérias-primas. Nesta contribuição técnica descrevem-se os testes realizados, avaliação dos mesmos e melhorias implantadas.

Aug 1, 2018

By Jacob Mathis, Mark Bradford, Alston Noronha, R. M. True

In June 2022, Louisville MSD completed a 6.5-km (4.0-mi), 6.1-m (20-ft.) diameter CSO conveyance and storage tunnel system located along the Ohio River in downtown Louisville, Kentucky. For large diameter shaft and tunnel construction, drill-and-blast operations among other methodologies were used in close proximity to federal, commercial, and residential properties with no impact to stakeholder infrastructure. s one of the rst maor tunneling proects in Louisvilles metropolitan area, this paper explores Black & Veatchs rigorous geotechnical instrumentation monitoring program that provided uality assurance for local stakeholders and afrmed innovative tunneling solutions can be successfully executed in an urban setting.

Jun 23, 2024

By Fennell B

A process for the recovery of cobalt from a speiss produced at Sulphide Corporation is presented. The speiss is leached in oxygenated sulphuric acid to dissolve the metallic iron at a pH of around 4. The resultant iron (11) is subsequently oxidized in the leaching vessel and precipitates as goethite. Acid is regenerated in the precipitation allowing dissolution of further speiss. Subsequent to the conversion of most of the iron in the speiss to goethite, conditions become sufficiently oxidizing to dissolve cobalt. Cobalt is not co-precipitated under the leaching conditions, yielding a pregnant solution containing the cobalt and some iron (11). The principal advantage of such a process is the significantly lower acid consumption over that obtained by complete dissolution followed by selective precipitation. An impure product of cobalt hydroxide can be obtained from the pregnant solution by neutralization.

Jan 1, 1983

The cost of preparing a feasibility study is notoriously difficult to estimate. Studies for mining projects are typically commenced when an exploration programme has identified a mineable resource and pre-feasibility studies have shown that development of the resource would lead to an economically viable project. Pre-feasibility studies will normally include an estimate of the cost of a formal feasibility study and this estimate would then be firmed up before a commitment is made to proceed with the formal study. Data for preparing the feasibility study cost estimate will be sketchy, geological investigations, metallurgical testwork, and marketing studies may be needed before the scope of the project and hence the scope of the formal study can be finally determined. Before an estimate of the work required and hence of the cost of the feasibility study can be prepared the source of project funds must be decided. Studies for internally funded projects are often less rigorous than those which must be "bankable" and subject to the scrutiny of external financial institutions. This paper sets out suggestions for preparing more accurate cost estimates for feasibility studies by ensuring that all activities are included and shows how a staged approach to preparing such studies can minimise costs and guard against cost overruns. It also provides a case study showing how the estimate compared with actual costs for a recent feasibility study completed by Pancontinental Mining Limited.

Jan 1, 1990

By D. Brady

When deciding to deploy rescue teams underground the decision makers need to be able to determine that there won?t be an explosion whilst the rescue teams are underground. Previously general body concentrations in areas likely to be travelled were compared to explosive limits on a one off basis with no formal process looking at trends or other areas. A new approach is being adopted that takes into account the rate of change of gas concentrations with triggers set to enable a withdrawal of personnel prior to a possible explosion and influences such a barometric pressure changes. This paper explains the rationale behind the changes made and the advantages and implications of adopting such an approach.

Jan 1, 2012

By William J. Wiehagen

The training of mining personnel is a large and continuing activity for the mineral industries. Although safety and skills training has long been recognized as an essential element for reducing injuries and improving productivity, the research literature lacks definitive reports documenting the specific value of such training. The training literature presents a variety of testimonials as to the "benefits of training," but lacks data that specifically tie that training to the performance of the worker.

Jan 1, 1983

By S. S. M. Chan

The Bureau of Mines has investigated the structural aspects of shafts and support systems using the finite-element technique. In situ field measurements in deep, vein-type metal mines show that rock stresses are often higher in the horizontal direction than the vertical, and unequal in the horizontal plane. These data and laboratory and field-determined physical properties were used as input to analytical studies. Various design and construction parameters were investigated to deter-mine the effect on shaft stability. Rectangular shafts were studied in detail to determine the effects of applied stress ratio, shaft orientation and dimension, influence of interbedded quartzite and argillite, and rock fracturing. Various support systems were analyzed, including concrete lining, timber, and steel sets. Circular configurations were investigated to evaluate yield zones and liner thickness. Elliptical shafts and time effects were briefly evaluated to illustrate shape and time effects and demonstrate the methodology. It is shown that the magnitude, direction, and ratio of applied stress and rock mass anisotropy are keys to determining shaft stability. A realistic conceptual framework was developed with which to examine the rock and support interaction in deep mine shafts. Structural analysis techniques overcome some of the historical difficulties with shaft de-sign by defining the field data requirements and structural sensitivity of various design and construction parameters.

Jan 1, 1985

By Sávia Cristina Lacerda Poubel Pinheiro

A cada sequencial iniciado, as primeiras toneladas de aços que caem no distribuidor podem ser contaminadas pelos refratários, bem como pelo oxigênio do ar. Na Aciaria da Vallourec Soluções Tubulares do Brasil (VSB), em Jeceaba, desde o start up tem-se como prática o sucateamento de aproximadamente 17 toneladas de aço no início de lingotamento, com o objetivo de minimizar problemas de qualidade no tubo devido fornecimento de barras com baixa qualidade. Neste contexto, estudos foram realizados para avaliar a qualidade destas primeiras barras de primeira corrida do sequencial, com foco em barras de diâmetro de 310mm. A avaliação compreendeu a análise do teor de oxigênio total ao longo da primeira barra e qualidade de tubos laminados provenientes das mesmas. Os resultados indicaram que parte da primeira barra apresenta boa qualidade para ser aplicada na laminação de tubos, reduzindo o sucateamento de barras de início de lingotamento em 7 t.

Oct 30, 2017

By C. G. Williams

IN preparing this paper on Canadian mine taxation, there has been no attempt to detail the requirements of the various taxing bodies; but rather to consider the matter from the standpoint of its underlying principles and give a general idea of the methods adopted. I have added an Appendix setting forth the principal features of the various Acts, which should be used for general reference only, since new rulings alter minor details from time to time. In current legislation, many important points are left to the discretion of the Ministers and their deputies. We are, indeed, fortunate in having in Canada an able and conscientious body of permanent officials, who bring a sense of justice and courtesy to their work which is most commendable, and which has done much to simplify the working out of general problems. The production of metals may rightly be deemed a form of manufacture, but differs from the average manufacturing business in three important respects: (1) In its early stages, it is wholly speculative, since it is impossible to make any definite appraisal of value or possibilities. (2) The principal asset of any mine, i.e., the ore in the ground, is a wasting asset, and is irreplaceable. (3) Any additional burden by way of taxation cannot be passed on to the public but must be borne entirely by the producer. Having regard to the first of these differences, it is apparent that, since the risk of loss is great, the reward in case of success must be correspondingly great. This fact seems to be constantly overlooked by those who regard the all too few outstanding successes in Canadian mining history as fit prey for predatory legislation. As an illustration of the speculative nature of early mining development, let us consider the Province of Ontario-and I take this illustration simply because I am more familiar with conditions there, and not because I believe it differs greatly from any other province. From 1907 to 1933, 165,243 claims were staked and recorded, from which 43 mines were developed which paid one or more dividends. There was, of course, some duplication through re-staking; also, on some claims very little work was done, and most mines have more than one claim. But, since staking and recording cost real money and effort, each of these claims must have been considered to have had merit.

Jan 1, 1935

By M. Abdellatif

Keywords: Magnesium, pyrometallurgy, Mintek Samples of crude magnesium produced by the Mintek Thermal Magnesium Process were refined in two stages. The first stage consisted of co-melting of batches of the crude metal and MgCl2-KCl flux (cleaning), followed by stirring at 30 rpm for 30 minutes and settling of the sludge (mixture of molten salt and solid impurities) from the magnesium melt. The operating temperature was 680?730°C. Most of the contained calcium and significant proportions of iron and silicon were transferred into the sludge phase, which left a metal containing, on average, 950 ppm Si, 470 ppm Fe, and 230 ppm Ca. In the second stage, small-scale refining tests were conducted on cleaned samples from the first stage, as well as on crude magnesium. FeCl3 was used as the refining agent. These tests were carried out at 715?760°C with various amounts of the refining agent. The refined metal was suitable for the production of various magnesium alloys, particularly AZ91D.

Jan 1, 2006

Experimental results are presented for the anode overvoltage as a function of current density for different alumina concentrations in an alumina reduction cell. Voltage changes due to the electrolyte resistance and also the decomposition voltage, have been evaluated as a function of alumina concentration and anode current density. From these values of voltage, changes in the total cell voltage have been derived for changes in alumina concentration for different anode current densities. The results show that for each operating current density there exists a discrete alumina concentration that defines a minimum reduction cell voltage. Discussion is made about potential savings in power consumption when the alumina concentration is controlled.INTRODUCTIONThe standard procedure in the aluminium industry when analysing the cell-voltage required for the Hall-Heroult process for reduction of alumina, is to subdivide the total voltage into the following components (e.g. Pearson, 1955; Maritell, 1960).1. ohmic drop through busbars and joints2. ohmic drop through cathode lining3. ohmic drop through anode4. ohmic drop through electrolyte5. overvoltage at anode6. electrolytic decomposition voltage.(Overvoltages ,at the cathode are of negligible magnitude at all practical current densities.)It is understandable that the voltages assigned for each factor invariably differ for different workers...

Jan 1, 1965

By H. A. Doerner

For the past three or four years attention has been attracted to the deposits of lead vanadate in the Goodsprings , Nevada , district . Some ore running as high as 9 per cent 205 has been produced , but most of it runs from 0.5 to 3 per cent . Only a little ore , and that of the richer sort , has been shipped , since the low- grade ore will not stend the cost of shipment and no concentration mill has been available . Preliminary experiments indicate that chemical treatment of the low- grade ore without concentration is not feasible . Its treatment therefore involves two distinct problems ; first , mechanical concentration ; and second , a smelting or chemical treatment to obtain the lead and vanadium in marketable form . Upon this basis the work has been conducted . The writer wishes to acknowledge the excellent work done by J. T. Norton and Virgil Miller on table concentration and by J. E. Conley , who suggested and did preliminary work on the direct smelting method . Many helpful suggestions were received from Dr. S. C. Lind and John Gross of the Bureau of Mines . The ores were furnished by Mr. Frank Williams and Mr. James Ewing .

Jan 1, 1923

By P Goblet, S A. Séguret, E Cordier, A Galli

In salar-type deposits, lithium grades can be measured by bailers introduced at different elevations in the drill holes at locations where, later, the brine will be pumped out to recover the metal. When they are duplicated, these a priori rudimentary measurements may show large differences without indicating whether this is due to the procedure itself or to some physical causes linked to the dynamic behaviour of the salar (seasonality, rainfall, underground flow etc). In the reservoir presented in the paper, the problem is complicated by the double lack of stationarity of the lithium grades: the grades not only increase importantly with the depth but at the same time their fluctuations decrease, making it necessary to use non-stationary geostatistical techniques to simulate them. Reservoir simulation is developed in two steps: first, geostatistical simulations of the lithium grade create possible realisations of the reservoir; then, each geostatistical simulation is followed by a pumping simulation that calculates, at each drill hole of a given extraction scenario, the lithium produced each year over 40 years. For the set of 100 simulations produced in this way, a scenario reduction is made to choose the five most representative simulations where more complex calculations will be carried out (for example, changing hydrogeological parameters such as porosity and permeability, or the elevation of the filters, the number and the location of the pumping and the reinjection drill holes etc). The paper first presents an analysis of the geostatistical model sensitivity to the grade uncertainty when measured by bailer. Among the 100 measurements at our disposal covering the future production domain, 50 per cent are duplicates measured at the same place but at different times. They are randomly sampled to produce five subsets of 75 values, which will constitute the future 3D conditioning points for the geostatistical analysis and the simulations. For each subset, trend, standard deviation and variogram models are fitted, leading to five sets of 20 geostatistical simulations of grades. In this way, the reliability of the different parameters involved in the procedure is evaluated, as well as its impact on the pumping results. Then, a reconciliation study is conducted between the non-stationary nugget effects encountered in the 3D variograms of the lithium grade and a pure statistical analysis of 25 duplicates measured at different locations and/or different times. The result is that if the nugget effect reaches 20 per cent, which is the case of three conditioning subsets out of five, the reconciliation is good and the nugget effect of the variogram model represents the bailer uncertainty, ie the measurement error. Since the geostatistical simulation incorporates a nugget effect, it handles the bailer uncertainty and the impact on the produced metal is included in the evaluation. The final conclusion is that, after the hydrogeological pumping simulations, the initial differences between the five geostatistical models do not influence the final results: lithium grades measured by bailers can lead to a robust evaluation of the extractable resources, a conclusion that conflicts with conventional wisdom.CITATION:Séguret, S A, Goblet, P, Cordier, E and Galli, A, 2017. Bailer uncertainty evaluation in a lithium salar deposit, in Proceedings Eighth World Conference on Sampling and Blending , pp 395–402 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

There is no doubt that the mining sector is considered to be the backbone of many countries. Furthermore, it has played an important role in the prosperity of nations, whether developed or developing. Saudi Arabia is one of these countries that has a large variety of metallic and non-metallic mineral resources that range in size and value occurrences of limited potential to deposits large enough to sustain profitable exploitation. Therefore, the Saudi government needs to reinforce the capacity of the sectoral institutions to better regulate and promote the sustainable development of the sector. The ability to overcome the administrative and legal complications that constrain private sector participation in the minerals sector, through new mining code which will streamline the procedures for obtaining licenses and will add more predictability and transparency to the application process, are proposed for increasing the sustainable development. This paper will outline how the Saudi government is tackling the major challenges that face the minerals industry. This paper provides the background to the Saudi Arabian mineral sector and its industrial base. Finally, the paper identifies the problems and constraints that face the minerals sector in Saudi Arabia and provides an assessment of the effects of government policies and planning efforts in the minerals sector, particularly during the period of the development plans which started in 1970.

Jan 1, 2009

By Jorge Alberto Soares Tenório, Denise Crocce Romano Espinosa, Amilton Barbosa Botelho Junior

A new step in the Bayer process has been used to recover NaOH and to reduce its content in red mud. After digestion, the residue is separated from the Bayer liquor and goes through press filters, which enables the recovery of NaOH and decreases the moisture content. It is well known that red mud is one of the most important sources of scandium. For this reason, the goal of this work was to characterize a Brazilian red mud (BRM) for scandium recovery. The sample was collected after the press filter system process. Analysis of energy-dispersive X-ray fluorescence (EDXRF), scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS), and X-ray diffraction (XRD) was performed. Microwave digestion using an acid mixture was carried out to determine the concentration of the main elements. Fe2O3 represented 40% of the BRM, and the Sc concentration was 43 mg/kg. The SiO2 content was 24%, which is the highest value found in the literature, whereas the sodium concentration was the lowest. A literature review was carried out to compare results with BRM, as well as the current studies for recovery of scandium by the leaching/ion-exchange process. Scandium recovery using a leaching/ion exchange process may be possible with efficiency higher than 90%. The greatest challenge is the occurrence of silica gel formation during leaching.

Oct 19, 2020

By Andy Fortin, Jeet Basi, Simon Hille

Goldcorp’s Eleonore mine is situated in Ell Lake area in the northeastern part of the Opinaca reservoir in the James Bay region of Quebec. The design of the 7000 t/d process plant includes crushing, grinding, bulk sulphide flotation, separate concentrate and tails leaching and detoxification circuits and residue handling. Detoxified flotation tails are thickened and filtered. A portion of the filtered tails are blended with the thickened detoxified sulphide concentration for paste backfill. The remaining filtered tails are trucked to the waste management facility. This presentation will describe the challenges faced with the commissioning and subsequent ramp-up of the flotation tails filter plant and the successes achieved by the multi-discipline team at Eleonore.

Jan 1, 2016

The stability of parallel underground coal mine galleries and pillars have been investigated using two- and three-dimensional (3D) numerical stress analysis. Anisotropic horizontal in situ stresses and the direction of the excavations have been considered in the numerical analysis. The stability of the tunnels driven in a coal seam at various working depths has been investigated taking into account different strata conditions and then results from two- and three-dimensional numerical modelling studies were compared. Maximum principal stress components have been chosen in three various directions: vertical, parallel and perpendicular to the tunnel axis. Analysis have shown that in the anisotropic in situ stress field, the favourable direction of underground mine openings which have different strata conditions depend not only on the horizontal in situ stresses but also on the vertical in situ stresses. Furthermore, 3D numerical modelling studies have been carried out to investigate stability of multiple entry longwall panel gate roads and pillars with various width-to-length ratios (W/L). Results of the modelling studies have shown that the critical dimension of coal pillars depends on their width and the direction of maximum horizontal stresses.

Dec 6, 2010