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Orange Free State Branch Minutes of a General Meeting held at the Welkom Mine Canteen on Wednesday, 21st November, 1973, at 4-.00 p.m. Present Mr E. T. Wilson (Chairman) in the Chair, 15 Fellows and Members, 12 Associates, Graduates, and Students, and 11 Visitors (Total 38). Book review Symposium on Environmental Engineering in Coal Mining The 20 papers presented at the symposium cover some 14 subjects related to environmental engineering in coal mines, such as dust, heat, gas emissions, ventilation, noise, and lighting. Competition for students Each year the Institute offers a prize (or prizes should the entries warrant it) of up to Rl00 for the best paper or dissertation on a topic appropriate to the interests of the Institute. A.8. & T.8. Trust The A.S. & T.S. Trust has been formed with the specific object of establishing a worthwhile source of funds which can be used to further the progress of science and technology in South Africa. Nim reports Report No. 1573 A pilot-plant investigation of a flotation model. Report No. 1597 The role of sulphur in the flotation of sulphide minerals. Report No. 1599 The analysis of silicate rocks and metallurgical slags by X -ray-fluorescence spectrometry. Report No. 1607 The analysis of ion-exchange resins by X-ray- fluorescence spectrometry. Report No. 1617 An electronic differential precision thermometer.

Jan 6, 1974

By Patricia Dillon

EHS Management Standards Communication and Reporting (8) ! Establish processes for internal and external communications ! Designate responsibilities for communication with COI ! Report as defined by senior management ! Report annually to employees, shareholders, COI on EHS and social performance Community Rights and Public Consultation (9) !Identify COI?s and establish process to hear concerns !Acknowledge and respond to complaints !Support local communities !Plan for closure and conduct public consultation !New projects include identification of COI?s, concerns to be considered in design

May 1, 2004

By F. H. A. Abdalla

A process is described for the recovery of valuable nonferrous metals from steelmaking dust by suiphatizing roasting using ammonium sulphate. Maximum recoveries of soluble metal sulphates achieved at optimum conditions were> 99.0 %. Selective metal separation of the soluble sulphates in the leached liquors were performed either by controlling the roasting temperature or by adjustment the pH values of the leached liquor ranging from 3.6-6.2. Either pure zinc oxide orland tin oxide could be obtained at optimum conditions, and the products were evaluated chemically and by X-ray analyses. The residues rich in iron oxide can be removed and recycled. The mechanism of sulphatizing roasting process was considered. A general flow-sheet for the overall process of treatment the steel making dust to recover its valuable nonferrous metals was suggested, which ca be applied for other nonferrous bearing materials.

Jan 1, 1996

By Raphael Calazans Cardoso

Os procedimentos de dimensionamento de juntas parafusadas devem corresponder adequadamente às condições impostas na prática, para garantir projetos de alta confiabilidade. Por isso, este estudo tem o objetivo de evoluir na compreensão do comportamento mecânico de juntas parafusadas submetidas à carga axial externa. Para tal foram realizadas simulações numéricas variando a pré-carga de aperto, o comprimento do parafuso, o atrito entre os componentes, a posição de aplicação da carga externa e os materiais dos membros apertados, de modo a verificar a parcela da carga externa transferida ao parafuso. Todos os fatores analisados alteram o comportamento mecânico da junta, exceto o atrito entre os componentes. A transmissão da carga ao parafuso se comporta de maneira não-linear pelo aumento da carga externa. Além disso, existe um patamar de carga externa abaixo do qual não há transferência de carga ao parafuso.

Oct 30, 2017

By Marius S. Darrow, William B. White, Rustum Roy

The PbS-PbTe systen has been studied by quench-ing and D.T.A. techniques f?om 400' to 1150°C. Runs were made in evacuated silica tubes so that all equilibria are at the vapor pressure of the system. Lattice parameters of the quenched salnples , measured by X-ray diffraction, show a complete crystalline-solution series existing over a narrow temperature range between approximately 805" and 871°C. An exsolution dome extends from a maximum of about 805"C (approximately 30 mole pct PbTe) to 1 and 96.5 pet PbTe at 400°C. A narrow melting region, deternined by D.T.A., extends form 918c (mp PbTe), The shapes of the liquides and solidus curves imply the existence of a minimum at 871°C at approximately 65 pct PbTe. THe exact composition of the minimum could not be established due to the very narrow two-phase region. At compositions containing less than 50 pet PbTe, liquidus temperatures begin to increase, while the solidus remains almost flat to about 15 mole pet PbTe before beginning to vise toward the mp of PbS (1075 C). LEAD sulfide and lead telluride are isostructural (NaC1 type) semiconductors whose electrical and optical properties have been extensively studied and used in recent years. If appreciable crystalline solution exists between these compounds, the variation of physical properties with composition could be of interest. The purpose of this investigation was to determine the extent, if any. of crystalline solution, and to obtain the phase diagram for the system. To the knowledge of the authors, only three studies of the system PbS-PbTe have been reported, and, in chronological order, each investigation found an increasing amount of crystalline solution. In 1956, Yamamoto reported finding no evidence of crystalline solution between the compounds. Sindeyeva and Godov-ikov,' in 1959, found very limited crystalline solution. but only under conditions of excess tellurium concentration. Finally Melevski s3 investigation in 1963 indicated that one solid phase exists in the region from PbS to 7 pct PbTe and from 82 pct PbTe to PbTe at 886'C, with an eutectic at 55 pct PbTe at that temperature. Detailed data on the solvus boundary were not given. EXPERIMENTAL EQUIPMENT AND MATERIALS Commercially produced PbTe and PbS powders were used as starting materials. Batches of specific mole percent composition were accurately weighed and mixed in a plastic bottle, in a shaker mill. An analy- sis of impurity content is given in Table I for pure PbS and PbTe and for two randomly selected batches after the powders were mixed. Individual samples, ranging in weight from 0.2 to 0.5 g, were sealed in evacuated silica tubes which had been thoroughly washed and rinsed with acetone and distilled water. Thus all data taken were at the pressure of the system. Subsolidus relations were studied down to 400°C by heating the samples in a vertical tube furnace for 24 hr. The sealed tubes were quenched in water with quench time from the hot zone not exceeding 1 sec. Temperatures were measured by a chromel-alumel thermocouple and controlled to 53°C for most runs. The number and composition of phases present were determined from powder X-ray diffraction patterns taken at room temperature on a Norelco diffractome-ter, using silicon as an external standard. Above 850°C quenching techniques were, in general, found to be unsatisfactory, and differential thermal analysis (D.T.A.) was used to determine melting relations. The evacuated tubes were recessed about 1 cm at one end to accommodate the differential thermocouple. Al203 was used as the reference material in a similar tube containing the other side of the differential couple. For temperature measurements, a separate thermocouple was placed in the recess of the tube containing the sample to be measured, thus providing an opportunity to obtain thermal, as well as differential, analysis. All thermocouples for these measurements were Pt-Pt 10 pct Rh. Temperature and differential curves were recorded separately on synchronized strip-chart recorders. Thermocouples and recording equipment were calibrated using NaCl and gold standards, using the melting points 801" and 1063 C, respectively, which span most of the temperature range of interest. Heating and cooling rates generally were from 4 to 7°C per min. It was found, in fact. that rates ranging from 1.5 to 25°C per min did not significantly change the data obtained.

Jan 1, 1967

By John W. Cabot

The fact has long been known, that the temperature at which steel is made and cast bears a very important relation to the molecular condition of the cast ingot. But until quite recently this fact has not received the consideration which its importance seems to justify. That the ingots from a very " hot " blow in the Bessemer converter, for instance, would not roll as well as those made at a lower temperature, was observed very early in the development of the process; but the further investigation of the effects of varying temperature from "hot" to "cold," has not been carried out with that degree of fulness which has been accorded to the effects on the rolling of the chemical elements, and other conditions in the manufacture. In the following pages will be presented the results of an investigation of this subject, undertaken with the view of determining how far the influence of temperature extends, through how great a range its effects can be traced, and what temperature in the making and casting will give the best results in the rolling of the ingots. In the series of observations forming the basis for the conclusions arrived at, while it was not possible to get the full chemical analysis of every heat considered, a complete record of each, in other details, was made, and a large number of these were averaged together to

Jan 1, 1886

The visitors to the October meeting will be given opportunity to visit the coal fields in Illinois, adjacent to St. Louis, the steam-shovel operations near Pittsburgh, Kan., and the Oklahoma oil fields. The coal mines of Illinois, Missouri, Kansas, Oklahoma and Arkansas furnish fuel over all of the central region of the country. Especially at this time, this district is of importance because of the necessity of producing enormous quantities to meet the country's demand. Some of the mines produce as much as 5,500 tons in 8 hr., and. the total output of Illinois, alone, in 1916, was 63,000,000 tons. Visitors may see elaborate underground electric tram systems, large underground machine repair shops, surface plants equipped for rapid loading, and some of the most modern coal-washing installations. The conditions for mining here are somewhat simpler than in the east.

Jan 8, 1917

By George J. Conroy, Angel G. Jordan, Eugene W. Bartel

Time-domain reflectometry has long been an accepted and used method for locating electrical faults in electrical cables. The process has, however, required the use of equipment that is somewhat complex and difficult to use. The skill level needed to operate such equipment is high. Therefore, the use of the time-domain reflectometry process has been limited to selected locations and controlled environments. The process, however, has great potential for mine system applications. The ability to locate and repair trailing power cable without removing it from the mine would result in great savings in cost and employee-hours. Therefore, an automatic microprocessor-controlled time- domain reflectometry system was developed to reduce process complexity and skill level needed to operate the unit. The theory of operations is discussed along with the computer analogies used in the unit. The present unit capabilities are presented and future areas of application and research are discussed.

Jan 1, 1979

By P. Middendorp, Gerald E. H. Verbeek

"INTRODUCTIONStatic Load Testing (SLT) is generally considered the pile testing method that provides the de-facto answers regarding pile capacity and load-deflection behavior. However, as this testing method is time consuming and costly, alternative pile testing methods are applied, such as High-Strain Dynamic Testing (HSDT), commonly referred to as Dynamic Load Testing (DLT), and Rapid Load Testing (RLT), which includes Statnamic Testing (STN) and the Fundex Pile Load Tester (PLT). Extensive descriptions of these pile testing methods as well as comparisons of the results from these two methods have been widely published, but little is written on the choice between HSDT and RLT. This article will address this issue for concrete piles by discussing five different aspects that should be considered when making a choice between HSDT and RLT for either cast-in-situ piles or precast driven piles. TIMINGThe timing of the pile load test is independent of the testing method. For cast-in-situ piles load testing is performed some time after the pile has been installed (to allow the pile to obtain the compressive strength required to withstand the test load), while for precast driven piles load testing is performed after a so-called set-up period following pile installation (to allow the soil to recover from driving induced disturbances and, at least in most cases,regain strength).In other words, the timing of the test does not affect the choice of the testing method.ACCURACY OF THE APPLIED LOADWhen a pile is tested by RLT the applied load is measured by a calibrated load cell placed on the pile head, just as it would be during SLT. This means that the error in the applied load value is less than 0.1% of the maximum range of the load cell.However, when a pile is tested by HSDT the load is calculated from the measured strains, which means that the outcome is dependent on the pile material properties. In this case the applied load (F) on the pile head is calculated by multiplying the measured strain (?) with either the calculated or estimated elastic modulus of concrete (E) and the pile cross section (A).The elastic modulus is generally back calculated from the (average) stress wave velocity (c), which in turn is derived from the reflection time (T) it takes for a stress wave to travel over the pile length (L) from the pile head to the pile toe and back to the pile head."

Jan 1, 2006

By Dae S. Young

A new probabilistic approach is introduced for slope stability analysis including adverse impact of blasting vibrations. The material strength within a slope area is randomized in this bi-variate joint probability analysis. To be a completely general engineering method, the new probabilistic approach employs the random variable transformation technique; the Hermite model of the Gaussian transformation function, which transforms the experimental histogram of strength values to the standard Gaussian variables. Because bi-normal joint probability is analyzed on the true probability region projected on the Gaussian transformed variable plane, it is an exact solution of slope stability based on the available sample data. Details of the probabilistic approach are given through a case study on an iron ore mine. The case study demonstrated that the probabilistic approach is effective and simple enough to be a routine engineering practice for slope analysis.

Jan 1, 1984

By Arcy P., D&apos Banister

Several gold-antimony geochemical anomalies were outlined near Stibnite, Idaho, using the humus sampling technique. Several hundred reconnaissance humus samples were collected and analyzed by a combination fire-assay atomic absorption method. The results partially outlined several gold-antimony anomalies and are very encouraging for further work in this part of Idaho.

Jan 1, 1970

By Ariella Vianna Fontes

A integridade estrutural das tubulações existentes em plantas de extração de óleo e gás é um dos grandes desafios na área de ensaios não destrutivos, visando garantir a segurança e eficiência da produção. Os dutos de plástico reforçados com fibra de vidro (PRFV) tem, progressivamente, substituído as ligas metálicas tradicionais por apresentarem alta resistência mecânica e a corrosão além de baixo peso específico. Todavia as conexões de vários trechos desses dutos, realizadas por juntas adesivas, podem apresentar defeitos como a falta de adesão e a falta de adesivo, tornando-se pontos propícios ao colapso. Até o momento ainda não há uma metodologia de ensaio não destrutivo consolidada capaz de avaliar a integridade das juntas adesivas. O presente trabalho apresenta a caracterização qualitativa e quantitativa dos defeitos típicos encontrados em juntas adesivas do tipo “ponto e bolsa” utilizando as técnicas de ultrassom e microtomografia. Os resultados mostraram que a técnica de ultrassom é promissora no que tange a detecção de defeitos em juntas adesivas, ainda que com limitações. A microtomografia mostrou-se adequada para caracterização qualitativa e quantitativa dos defeitos visto que esta permite analisar a estrutura interna do material.

Oct 30, 2017

By А. V. Aksenov, S. G. Rybkin, А. Y. Senchenko

For gold plants in Russia, it is very complicated and costly to use cyanide leaching for efficient processing of gold refractory ores, where gold is closely associated with sulphide minerals and the significant amount of natural carbonaceous matter present. Oxidative roasting of gold refractory concentrates is a well-known method, making it possible to obtain a high recovery rate of precious metals to a target product. The use of oxidative roasting is limited in general by the expense of capturing and neutralising the harmful components of roasted gas, mainly sulphur (SO2, SO3) and arsenic (As2O3) oxides. This paper addresses testing and development of an optimised technology to process gold refractory gravity and flotation concentrates by means of oxidative roasting which stabilises arsenic as calcium arsenate. The process involves roasting of a gravity or flotation refractory ore concentrate in a mixture with lime and calcium chloride, with a supply of oxygen, and at 600-700°С. During the roasting a carbonaceous matter of the concentrate burns out and sulphide components transform into harmless calcium sulphate (CaSO4) and calcium arsenate (Ca3(AsO4)2), and iron passes into the form of hematite (Fe2O3). After disintegration, the roasting cinder is concentrated on a table to obtain a high-grade gravity concentrate and gravity tailings. The high-grade gravity concentrate is subject to smelting in a mixture with fluxing agents, which results in alloyed gold and slag. The gravity tailings are ground and reported to cyanide leaching. In the case of a flotation concentrate, the roast cinder is ground to minus 30 μm and subject to sorption cyanide leaching. High gold recovery (90-95%) of the target product and environmental safety are typical of the improved technology under consideration. Two national patents were granted for the methods developed to treat refractory concentrates bearing precious metals. Keywords: Gold concentrates, oxidative roasting, cinder, cyanide leaching, smelting, alloyed gold

Jan 1, 2020

By David E. Nicholas

INTRODUCTION In this paper, a numerical process for selecting a mining method, with the emphasis on underground mass mining techniques, such as caving, induced caving, and stoping, is proposed. In the past, selection of a mining method for a new property was based primarily on operating experience at similar type deposits and on methods already in use in the district of the deposit. Then, the chosen method was modified during the early years of mining as ground conditions and ore character were bet- ter understood. Today, however, the large capital investment required to open a new mine or change an existing mining system make it imperative that the mining methods examined during the feasibility studies and the method actually selected have a high probability of attaining the projected production rates. Although experience and engineering judgment still provide major input into the selection of a mining method, subtle differences in the characteristics of each deposit, which may affect the method chosen or the mine design, can usually be perceived only through analysis of measured characteristics. The parameters that must be examined when choosing a mining method include: 1) geometry and grade distribution of the deposit; 2) rock mass strength for the ore zone, the hanging wall, and the footwall; 3) mining costs and capitalization requirements; 4) mining rate; 5) type and availability of labor; 6) environmental concerns; and 7) other site-specific considerations. This paper encompasses a detailed look at the first two parameters since they, plus mining costs, have the greatest impact on the selection of a mining method. The proposed method selection process is for a project where drilling has defined sufficient geologic reserves, but little or no underground development has been done. Since each deposit has its own characteristic geanetry/grade distribution, and rock mechanics properties, mining method selection should be at least a two-stage process. In Stage 1, the deposit is described in terms of geometry, grade distribution, and rock mechanics properties. Using these parameters, the mining methods can be ranked to determine which are most applicable; they can then be considered in general terms of mining and capitalization cost, mining rate, type and availability of personnel, environmental concerns, and other site-specific considerations. In Stage 2, the most likely mining methods are costed out, based on a general mine plan. Mining and capitalization costs are used to determine a cut-off grade fran which a minable reserve can be calculated; economic comparisons can then be made to determine the optimum mining method and economic feasibility. During the mine planning phase of Stage 2, rock mechanics information would be used to provide realistic estimates of underground opening size, amount of support, orientation of openings, and caving characteristics, and open pit slope angles. If ground control or operational problems should be encountered with the methods being considered, modifications could be made. Although planning on paper extends start-up time, it is cheaper to err on paper than to find the error after mining has begun. METHOD SELECTION - STAGE 1 The main purpose of Stage 1 is to select those mining methods which should be considered in greater detail. The simplest way to do this is by defining those characteristics required for each mining method and then determining whether the characteristics of the deposit are suitable. However, no one mining method is so restrictive that it can be used for only one set of characteristics, as indicated by the classification system proposed by Boshkov and Wright (1973). In the mining method selection proposed, geometry, grade distribution, and rock mechanics characteristics are ranked according to their acceptability for ten general mining methods.

Jan 1, 1981

By S. D. Bearden

Color enhances expression and communication in all physical objects experienced in life. Pigments provide color and in some applications have a specific additional function. Natural iron oxides are widely distributed throughout the world but only a few deposits are sufficiently pure and possess acceptable color and brightness properties to merit their processing into pigment form. Ochre, the common name for goethite ore, is the best and most under used material in the buff colored pigment market. The geological occurrence of ochre in the basal Shady Formation of the Cartersville Mining District (Georgia) is described. Exploration, processing, and product applications of New Riverside Ochre Company, Inc. are discussed. An overview of the worldwide pigment market is presented with emphasis placed upon the North American activity in iron oxide production and application. The purpose of this paper is to increase the awareness of ochre and its potential market in the colored iron oxide pigment industry, encourage research on the origin of ochre deposits, and stimulate interest in new applications of this unique substance.

Feb 27, 2013

By V. G. Prikhodko, G. I. Sukhinin, I. V. Yarygin, A. V. Fedoseev, S. A. Novopashin

"The first experiments on the vacuum drying of spherical clay sample are presented and the theoretical model of the process is considered. The model is based on the solution of the heat and the moisture transfer equations with the effective thermal conductivity and water diffusion coefficients for wet porous clay-like medium. The time and radial dependence of the temperature and the moisture were calculated for different initial conditions. The results obtained for the time dependence of the moisture content are in good agreement with the experimental results obtained in the initial period, when all the moisture in the sample did not freeze to form an ice crust. INTRODUCTION Capillary-porous materials very often occur in nature and in industry. A porous medium is a solid matrix with voids, or pores, which are continuously connected. These pores are usually filled with fluids or moisture, water vapor and air that can pass through the medium because the voids are interconnected. The void fraction in the solid matrix is referred to as the porosity. Porosity or void fraction is a measure of the void (i.e. ""empty"") spaces in a material, and is a fraction of the volume of voids over the total volume. The moisture content in porous media determines the properties of the porous body, its mechanical and thermo-physical properties, such as density, plasticity, viscoelasticity, swelling, cracking, and so on. Complex processes of heat and mass transfer occur in porous bodies when they are heated or cooled, during drying or freezing (Luikov,1966). The course of these processes depends essentially on the physical-chemical composition of the solid matrix of the porous body, on its fractal dimension, porosity and morphology. The clay and clay minerals are the most important porous materials in the history of the mankind (Mukherjee, 2013). Clay is a very fine grained, unconsolidated rock matter, which is plastic when wet, but becomes hard and stony when heated. It has its origin in natural processes, mostly complex weathering, transported and deposited by sedimentation within geological periods. Clay is composed of silica {SiO2), Alumina (Al2O3) and water (H2O) plus appreciable concentrations of oxides of iron, alkali and alkaline earth, and contains groups of crystalline substances such as quartz, feldspar, and mica. Building materials, bricks, and tiles, pottery, porcelain and faience are made from clay. Clay is used in the food and medical industry, and, not least, in the mining industry as a carrier containing aluminum, silicon and other valuable elements, as well as metals (copper, gold) as constituents, contained in the pores in the form of micro- and nano-particles or grains."

Jan 1, 2018

The Gosowong epithermal quartz-adularia vein, in the Halmahera magmatic arc, is a new discovery in an area of primary tropical rain forest with no history of gold mining or mineralization. The newly recognized mineral district also contains a number of other epithermal vein systems, two centres of porphyry Cu-Au mineralization, and a number of argillic and advanced argillic alteration zones that may be related to underlying mineralization. Gosowong was discovered and tested through the application of basic exploration techniques including drainage sampling, soil sampling, trenching, magnetics, IP, and diamond drilling. Lapse time from the initial reconnaissance discovery of a stream sediment anomaly to the release of inferred resource estimates of approximately 1.0m ounces was just over 3 years.

Jan 1, 1997

By Thomas Egleston

The adoption of the regenerative principle for burning fire-bricks, pottery, etc., has been delayed beyond what would naturally have been expected, because there bas been until recently little necessity for high heat in burning such material. But the introduction of pro-

Jan 1, 1887

By Bradley C. Bockrath

Some thirty coals were evaluated for liquefaction activity under a mixture of CO and H2 at 425° C. The viscosity of the liquid products was taken as an indicator of the degree of liquefaction. It was found that the direct liquefaction of a particular coal may be beneficially influenced by the presence of pyrite. Active pyrites are often found in the native mineral matter of the coal itself. For example, subbituminous and bituminous coals and lignites of relatively high pyrite content were found to liquefy more readily than similar coals or lignites which were poor in pyrite. The reactivity of inactive coals could be improved by using blends with active, pyrite-rich coals. In addition, pyrite was effective when added separately as pyrite concentrates obtained from coal beneficiation operations. Various other iron- and sulfur-bearing additives were also effective when used in combination as added slurry-phase catalysts, including iron oxides and mineral residues derived from liquefaction of active coals. Under liquefaction conditions, pyrrhotite ( Fe I- x5) is formed from pyrite or from the iron oxides and many sulfur containing species. Pyrrhotite was shown to be a hydrogenation/dehydrogenation catalyst for tetralin but is not active for initiating a variety of free radical reactions that do occur when pyrite is heated with tetralin. The role of pyrite in coal liquefaction is complex and still not well understood.

Jan 1, 1981

By J. T. Winkelmann

The Mineral Park Mine is an open pit copper-molybdenum mine located in northwestern Arizona, approximately twenty miles northwest of Kingman, Arizona. The concentrating facility has been regarded, with the expansion in 2011, as a plant capable of treating fifty thousand short tons of feed per day for the mixture of supergene and hypogene ores available. The grinding circuit consists of two 32? x 14? SAG mills and four 20? x 28? ball mills. As ores became harder with greater depth in the adjacent pit areas, however, the SAG mills became severely throughput limited. The traditional treatment for similar properties is the installation of a recycle pebble crushing circuit. Because the cost of such an installation is quite elevated, and preliminary testing and research was inconclusive regarding the predicted throughput increases, management and technical personnel set out to find another solution to the problem. The result entailed a redesign of SAG lifters/liners and a nearly unique circuit change which was, at best, a difficult step that defied current grinding logic. This paper describes these changes, events leading up to them, and the results.

Feb 23, 2014