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By Jun Xiao, Jianwen Yang, Yanhong Dong, Daixiong Chen

"MANGOTE Surface oxidizied mine is a gold-bearing deposit in Congo's Mai-Ndombe Province. In the past decades, the ore has been exploited in a crude way by local farmers, which directly causes the severe processing difficulty and lack of economy of cyanide leaching. Hunan Research Institute for Non-ferrous metals (HRIM) is currently investigating options to recover gold through understanding the mineralogical characteristics of MANGOTE surface oxidized ore. Chemical analysis , X-ray diffraction(XRD) and Quantitative Evaluation of Minerals by SCANing electron microscopy (QEMSCAN ) were conducted on samples from mine site. The bulk analysis results showed that gold separation of gold from gangue minerals was feasible after grinding the ore samples to 86.53% -74µm and adjusting the pulp specific weight at 100g/L, and gravity separation was conducted with using spiral chute after grading of fine particles. The research results highlight relationship between mineralogical characteristics of abandoned ore and economy of comprehensive utilization that might be directive experience to similar cases. INTRODUCTION The occurrence state of gold in natural gold minerals determines the basic recovery and recovery effect of gold(Komnitsas, C., & Pooley, F. D. 1989). The occurrence of gold in the ore refers to the form of gold in the ore.Generally the existing state of gold can be divided into four major categories according to the viewpoint of the dispersion system: independent minerals and gold, a coarse dispersed system;colloidal gold, a colloidal dispersion; solid solution gold, is atomic ion dispersion; adsorptive gold, according to the adsorbed particle is the micelle or ion, respectively is a colloidal dispersion or ion dispersion(Mao, S. D., & Yang, R. S. 2009; Liu, J. J. et al. 2007; Horisberger, M., & Rosset, J. 1977; Li, Y., & Audétat, A. 2013).With the increasing technology of comprehensive utilization of resources,varied plants can now process different gold ores with various occurrence states(Neesse, T. 2014; 7. Ogundare. et al.2014)."

Jan 1, 2018

By Richard N. Appling

This compilation presents information obtained through investigation of manganese deposits and a reconnaissance of potential manganese-bearing areas of southwestern Oregon and Del Norte County, Calif., from October 1952 to September 1955. The report includes maps, assays, and preliminary examination data on 39 manganese deposits distributed throughout Curry, Coos, Douglas, Josephine, and Jackson Counties, Oreg., and 1 deposit in Del Norte County, Calif. On the basis of mineral content the deposits can be divided into three groups: 1 Manganese silicate deposits, manganese oxide deposits, and manganiferous iron de-posits. Generally the oxides occur along the coast in the Curry-Coos County area, the manganiferous iron deposits are in the Josephine-Douglas area, and the manganese silicates are found in both the Josephine-Douglas and Jackson County areas. The deposits are characteristically irregular in form and usually small. Most silicate and manganiferous iron deposits are in metasediments of Triassic (?) age; oxide deposits are in sediments varying in age from Jurassic to Eocene.

Jan 1, 1957

By O Arafat, R E. McIvor, K M. Bartholomew

It is well known in the industry that good classification system performance is vital to efficient ball mill circuit performance. But what is meant by good classification system performance, and how is it achieved? Unfortunately, the perceived complexity of classification systems, and the day-to-day time demands placed on the practicing metallurgist, all too often put the low-hanging fruit of classification system optimisation in the ‘I’ll do it later’ basket. Additionally, lingering confusion about basics such as the relationship between circulating load ratio and ball mill circuit performance makes the optimisation objective seem nebulous to both plant metallurgist and designer.Some of this confusion can be eliminated by taking a step back from the overwhelming detail of sharpness of separation curves, circulating load ratios, cyclone feed pressures, vortex and apex sizes etc, and focusing on the purpose or function of the classification system – to apply mill power to particles that need further size reduction! The classification system efficiency (CSE) metric captures how well the classification system is performing its function with two quick and easy size distribution analyses.Once CSE is understood and implemented as the optimisation criteria, well-tested methods for improving CSE can be implemented and quickly measured at plant scale to give confidence that the right change was made.This paper will describe CSE and how it is measured in practice. Next, a guide for improving CSE through manipulation of design and operating variables in the classification system will be provided. Examples and case studies will illustrate the gains in ball mill circuit efficiency that can be achieved by maximising CSE.CITATION:Bartholomew, K M, McIvor, R E and Arafat, O, 2018. A guide to maximising ball mill circuit classification system efficiency (CSE), for operators and equipment designers, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 553–558 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By D. J. Frey

While costs of most commodities and services have increased markedly over the past 25 years, the cost of electricity has steadily declined. One of the reasons for this price decline is the improved efficiencies of generating plants which is shown in Fig. 1. 1,2 Another reason for this is the decline in coal production costs. Efficiencies for the best plant increased from about 32 percent in 1540 to about 40 percent in 1962 and then decreased slightly to 38 percent in 1965. The increase in efficiency for all plants (US average) has been even more notable, progressing from less than 15 percent in 1940 to about 32 percent in 1965. The chief reason for the improved efficiency is the change in operating steam temperatures. These increased about 12 F per year until 1200 F was reached in 1962. At this high temperature excessive corrosion of super-heater and reheater tubes was experienced and steam temperatures were dropped back to 1050 F and even 1000 F in some cases. To successfully compete against other energy sources for generating electricity, this corrosion problem must be solved so that operation at higher temperatures and thus, increased efficiencies will be possible.

Jan 1, 1967

By C. V. Millikan

THE year 1930 in the petroleum industry has been characterized by the establishment of large potential production of crude oil. This has resulted in closer cooperation between companies by proration and unit operation agreements in order to afford an equitable outlet to all, and to prevent a flood of oil being forced on the market with attendant tremendous material and economic waste. Drilling wells in proved areas and wildcat wells are fewer than in the past several years. Restricted production and low prices have caused greater effort to increase producing and recovery efficiencies. Increased refinery efficiencies have amplified the effect of overproduction. Pipe line departments have been especially busy. New oil lines have reached more refineries by new and shorter routes. Establishing greater gas reserves by new fields has justified new gas lines to industrial centers, and has brought this fuel to thousands of new domestic consumers. Two long gasoline lines, a new venture in pipe lines, are being built to obtain a lower cost of transportation and less loss between the refineries and their distribution centers. The chairmen of the various divisions have discussed the developments of their respective branches more fully in the following reviews.

Jan 1, 1931

This paper describes the integration of the mineral resource management philosophy within strategic long term planning at Anglo Platinum Limited. Consideration is given to the philosophy, processes, techniques and supporting systems.

Jan 1, 2007

By Charles Camsell

At the last annual meeting of this Institute the programme very properly was drawn up and carried out with the special object of calling attention to the Dominion's position and problems with regard to fuel supplies. That subject, always one of serious concern, was a source of considerable anxiety twelve months ago. It is still so, but in a decidedly less degree than at that time. So far as the immediate fuel situation is concerned our anxieties have been relieved. And I think we can safely say that such a consciousness of our difficulties and determination to overcome them, has been developed in the minds of our people that there will be no slackening of the offensive until a final solution is reached. In selecting a subject of major importance for the present occasion I have felt free to digress from the pressing problems of last year and to go back, for a starting point, to the presidential address of two years ago .. I do not, however, wish to enter the controversy that has developed as a result of that address, though in spite of my own failure to amass a fortune from participation in certain mining ventures, I am decidedly inclined to the optimistic view that Dr. Corless presented of the future of our mining industry. You will perhaps have observed that in its general wording the title of my paper bears a marked resemblance to that of that address. This simila1ity of titles is not accidental. It is intentional on my part.

Jan 1, 1924

By C. C. Jobes

Operating large face equipment, such as continuous mining machines, is one of the most basic and most dangerous elements of an underground coal mining operation. The operator usually performs cutting and tramming tasks in a restricted workspace with reduced visibility. During the execution of these tasks, operators often cannot see all of the locations needed to safely operate the continuous mining machine (CM ), which has sometimes resulted in accidents. In an effort to prevent these accidents, researchers at the National Institute for Occupational Safety and Health (NIOSH), Pittsburgh Research Laboratory, examined the continuous mining machine operator?s current information cues, or visual attention locations, so that risk of injury relative to the task, equipment and workplace environment can be evaluated in the future. The eventual goal is to develop interventions to enhance the information cues, and thereby increase the safety and health of machine operators. This paper details the operator interview process, determination of visual attention locations (VALs) and simulation of various mining scenarios.

Jan 1, 2011

By Luis Martín Tejada Cervantes

Generalmente, después de la etapa de cierre del depósito de relaves, se utilizan sistemas de protección ambiental tales como las coberturas -en tanto evitan el derrame de los residuos en suelos y fuentes de agua y las inestabilizaciones físicas y químicas. En ese sentido, el presente texto describe una evaluación geotécnica de flujo, equilibrio y deformación para la etapa de cierre de minas, considerando aspectos técnicos, de seguridad y medioambientales con fines de mitigación del impacto ambiental.

Jan 1, 2014

By M. P. Oommen

This paper provides a brief look at a proposed short-longwall for coal, development. The proposed method is an attempt to realize the advantages of longwall mining in deposits that, historically, would only be minable by continuous mining methods. An overview of the proposed layout, development requirements, production rate, ventilation scheme and other associated features is provided. This mining method could help operators in above-drainage seams where minable areas are smaller. It may also have application in areas that are peppered with gas wells and in environmentally sensitive areas which preclude the use of conventional longwalls.

Jan 1, 1993

By Pascual Martínez Rosales

El presente trabajo describe el proceso de mineralización de plata en rocas estratificadas del Paleozoico Inferior en el distrito de Santa Rosa, departamento de Cerro de Pasco. Dicha provincia metalogénetica posee las siguientes característicias: vetas en fillitas y cuarcitas que en otras provincias metalogenéticas no son favorables a la mlneralización; asociación de minerales de alta y baja temperatura mezclados como estanita, marmanita, pirrotita; poca fugacidad de azufre en la solución mineralizante, alta temperatura; baja presión en la mineralización del yacimiento, y su alta ley de plata en los cuerpos mineralizados dentro de las estructuras mineralizadas. En este sentido y dada sus particularidades, el tipo de flujo mineralizante de dicho yacimiento minero resulta ser el más adecuado e importante dentro del proceso de mineralización.

Oct 14, 1980

By Deming Wang, R. A. Overfelt

"This paper presents a computer-aided heat transfer simulation method to predict the thermal characteristics of an alloy sample in a special furnace for directional solidification. A two-dimensional transient heat transfer by conduction combined with radiation is developed to calculate the energy exchange between a directional solidification furnace and the sample. Finite difference equations with control volumes are used to calculate the transient heat transfer. A special boundary control volume is used to combine heat conduction and radiation in the transient heat transfer. Heat radiation effects on the surfaces of the special control volumes with a changeable view factor during directional solidification processing are also represented. The simulation results are verified by measurable experimental data. Using the computer simulation model, many thermal properties of the directional solidified castings can be obtained, such as temperature distribution, solidification velocity, the shapes and positions of the liquid/solid interface and thermal gradient at the interfaces. These are very important to analyze microstructure of casting alloys, avoid casting defects and control casting quality. 1 IntroductionIn directional solidification (DS) processing of castings, the temperature distribution, the interface between liquid and solid zone, thermal gradient in the mushy (pasty) zone and solidification rates are very important factors to analyze the microstructure and the casting quality. These variables affect the orientation and size of dendrites, shapes of grains, solute segregation and deleterious casting defects, such as microporosity, freckles and segregation channels. In order to avoid the casting defects, the temperature distribution and thermal gradients of castings during directional solidification must be strictly controlled. However, the structure of furnaces used for directional solidification is often complex. Heat transfer and temperature distribution within a casting not only depend on furnace temperature but also on the thermal properties of the casting alloy, crucibles, retorts etc. A more accurate heat transfer analysis."

Jan 1, 2001

By A. S. MacNeil

In the operation of any colliery, a factor of prime importance is power, of which there are three sources available--man, horse, and mechanical. It is obvious that man-power is by far the most expensive, .and that animal-power, also, is more costly than mechanical. In recognition of this fact, mine owners must, for economical ?reasons, reduce the use of man-and horse-power to the minimum by the increased use of machinery. In other words, they must aim at as complete mechanization as conditions will permit, taking advantage of existing physical factors that are favourable and making the necessary adjustments and modifications to meet the less favourable conditions. Intensive coal-mining, or the concentrated production of coal, has two distinct objectives: First, the maximum production from a limited area, in a given time, thereby reducing the pit-room to be maintained; and second, reduction in cost. To this end the coal should be mined, loaded and delivered to the surface by mechanical means wherever possible. To do this, however, requires the solution of many problems arising out of the varying conditions that obtain underground. The system of longwall mining lends itself to a more efficient scheme of mechanization than does pillar-and-room, as, in the former, the first step has already been taken by the removal of all the coal in one operation, and the opening-out of one face, the equivalent in mining area of fifteen or more rooms. Much has been clone of late towards mechanization in the longwall mines of the Sydney coal-field, and with gratifying results, but not without great difficulties and frequent disappointments. In 1923, an attempt was made with shaker conveyors. The introduction of conveying was a step to bridge the gap between the face, where the coal is produced, and the main transportation arteries leading to the slope or shaft. The receiving of the coal at the faces and its delivery to main loading points on main haulage-ways was the part allotted to the conveyors.

Jan 1, 1932

By Héctor Ugarte y Chamorro

El presento trabajo revisa las diversas medidas preventivas de seguridad minera que se dieron en el periodo colonial peruano. Durante la colonia, la deplorable situación económica y social del indio, conlleva una reacción de defensa humanitaria por parte de los frailes a través de leyes en favor de los indios. Posteriormente en 1551, el virrey La Gasca elaboró una serie de medidas como "Las leyes de indias", "Las ordenanzas de nuevos descubrimientos y poblaciones",entre otros, que protegian a los indios. En 1783 se dictaron "Las Ordenanzas de minería" para la nueva España y fue el virrey Francisco de Toledo, el primero en dictaminar la construcción de pozos y puentes en lugares convenientes, castigando a los infractores. En su Ordenanza II, refiere el caso de las minas de Potosí y ordena no desbaratar puentes ni pilares para evitar riesgos inútiles, mientras que su Ordenanza III dispone la regulación de las escaleras seguras de scrinejas. Asimismo prohibió el trabajo de menores de edad y el "pallaqueo" de mujeres en la mina. En cuanto a la salud ocupacional refiere, el virrrey Toledo dispuso la distancia entre el humo generado por el plomo y zinc, y los trabajadores, asi como su indemnización durante tres meses. Don Juan Solórzano fue otro de los partidarios que ordenó la eliminación del régimen de "obrajes"puesto que era excesivo para la salud de los indios. Las "Ordenanzas de la minería" rescatan también la valía de los operadores mineros, así como las "Declaraciones de Escobedo", donde se estableció la ventilación en el lugar a explotar y la supervisión adecuada de parte de un guardaminas calificado por algú facultativo de la minería. Tanto estas ordenanzas como otras disposiciones tuvieron su base en el Derecho romano. Finalmente, en los inicios de la República, el químico y primer director general de minería, Mariano Eduardo de Rivero y Ustaríz inspeccionó los centros mineros de Puno y Huancavelica, y dictaminó un decreto como medidas de protección para los obreros expuestos a enfermedades y accidentes ocasionados por el mercurio. Dicho decreto está compuesto por 8 considerandos y 4 artículos y apela a los conciudadanos a cumplir las normas en beneficio, salud y seguridad de los trabajadores mineros.

Jul 20, 1959

By D. J. DeLeo

In recent years the hue and cry of American industry concerning the pressure of foreign competition on the domestic marketplace has become all too familiar to most of us, as we are all well aware, the steel industry has not been exempted from this pressure, reduced production levels, work force cutbacks, and in some extreme cases, plant closings and company liquidations have resulted, new regulations governing imports and quotas have been enacted, foreign trade agreements reached, and more strict regulation enforcement practices undertaken, despite these, and other measures, the impact of aggressive foreign competition has not lessened, the concensus of numerous management consultants is that in order to successfully cope with these problems we must draw on all available technology to provide the tools which will enable us to enhance our management effectiveness, one area requiring particularly close attention in any mining operation is that of managing critical resources - namely time, energy and equipment in a fast and efficient manner, In mining, with critical resources deployed over a large geographical area, any degree of success involved with resource management is dependent upon knowing the current status of all work related activities, if we, as mine operators, are to be more successful in this area, additional tools are a necessity and modern technology has provided a multitude of new options from which to choose.

Jan 1, 1985

By Alexandre Alex) J. Bredikhin

"DISCLAIMER: the statements presented herein are those of the author and do not necessarily represent the views of US DoD or its Components.ABSTRACTProgress on the $750M lock project on the Monongahela River was derailed by discovery of large anomalies in the 6.5-7-ft dia. drilled shafts of the new river wall foundation. The anomalies were located 45 to 50’ below the top of the wall at the critical shaft-to-wall interface, and ranged in thickness from several inches to 2-plus feet. A Specialty team, comprised of representatives from the contractor, the Government, and structural design consultants, was formed to evaluate the extent of the problem and the impact on the new lock wall. With no standard method in place, the Government took the lead to develop acceptance criteria for the repairs while the contractor took the lead to identify the repair means and methods. The Government developed a detailed Quality Control plan to capture and document all of the repair data and to approve each shaft repair in a timely manner. This paper provides an overview of the anomalies encountered and the need for repairs; discusses the details of the repair plan; and provides details on the unique quality control measures employed to verify the repairs. By developing and adhering to a detailed quality control plan, the structural integrity of all of the shafts was successfully restored.INTRODUCTIONThe new Charleroi Locks Project is currently under construction by the U.S. Army Corps of Engineers (USACE) in Pittsburgh, Pennsylvania. In the region, the Corps of Engineers is modernizing the series of locks and dams on the Monongahela River. One facet of this modernization is replacement of the existing Locks #4 (aka Charleroi Locks) located upstream of Pittsburgh, Pennsylvania with new and larger capacity locks. The relative location of the project is shown on Fig. 1. The original construction of twin locks (56’x720’ & 56’x360’) and the fixed-crest dam was completed in 1932, with lock walls supported on timber pile foundations. The fixed crest dam was replaced with a gated dam in the 1960’s. The existing lock is undersized and in poor condition and thus needs to be replaced. The project requires the construction of the new river chamber adjacent to the existing land chamber which must remain operational to navigation throughout the construction. In order to accomplish this, the lock walls need to be constructed in the wet. The river wall was constructed using two construction methods referred to on the project as “cofferbox” and “non-cofferbox” construction."

Jan 1, 2017

By R. Carson Dalzell

The use of nuclear fission for chemical process heat offers the special advantage of high temperature, limited only by materials of construction. The process heat may be supplied economically at elevated pressures, since no compression of combustion air is required. For the initial effort in developing a high-temperature reactor, the indirect cycle, using helium as the heat-transfer medium, was chosen. The major problems are the design of high-temperature fuel elements, construction of an exchanger to transfer heat to process streams in the range of 2,500° F., and development of compressors capable of recycling helium at 1,000° F. and above. A conceptual design of a nuclear reactor to furnish process heat for coal gasification has been made. Spherical fuel elements utilizing a graphite structure, impregnated with uranium carbide fuel, were chosen, as spheres offer the possibility of easier loading and unloading of the reactor. Calculations of pressure drop and gas-pumping power for the system are included.

Jan 1, 1959

By Robert W. Burns

Gentlemen, my subject today is glass reinforced plastics. By definition, this encompasses a wide variety of materials: at least a half dozen basic varieties of polyester, epoxy, and phenolic; virtually infinite compounding variations within the basic groups: literally limitless variations in the amount and the nature of the glass reinforcing. Complicating all of this is the fact that different modes of application of the same material fall appreciably alter' the product's general strength and suitability. These many, many differing materials are what we conveniently call "glass reinforced plastics" or, more simply, fiberglass". This common name is actually a large part of the problem when dealing with fiberglass materials. Far too often a specification is written calling for simply "fiberglass reinforced polyester', based on successful prior use of a polyester laminate. Such a specification is very nearly worthless since such tremendous variation is possible under it. Success of a laminate furnished under such a specification is entirely dependent on good fortune

Jan 1, 1962

By Julio Tovar, Samuel Quisca

La lixiviación de metales pesados y la inestabilidad de taludes de los depósitos de relaves en la minería causan serios problemas ambientales de contaminación, que originan riesgos de salud y de seguridad de las poblaciones. Frente a esta problemática, es primordial eliminar o controlar los lixiviados tóxicos de los relaves y mejorar su estabilidad física, con el propósito de reducir el impacto ambiental de los contaminantes en los recursos de agua y suelos, así como asegurar la seguridad física de las relaveras, a fin de ganar la confianza de los stakeholder.

Sep 29, 2023

By William W. Adams

Not since complete records of accidents first became available has the safety record of the quarrying and related industries of the United States been as favorable as it was in 1940. The combined accident-frequency rate was lower and therefore better than in any year since 1916, the first year for which complete and comparable figures are available. Although operating companies began to furnish accident reports to the Bureau of Mines in 1911, the reports for that year and the next few years were obviously incomplete as to number of accidents reported, especially slight injuries involving only 1 or 2 days of disability of the injured employees. By 1916 the reports from operating companies appeared to be reliable as to completeness of coverage of slight injuries. Although the number of men employed in 1940 was by no means a record, it represented a gain over each of the 2 preceding years. Likewise, the number of man-hours worked during 1940 was larger than in 1938 and 1939.

Jan 1, 1942