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By P. R. Khangoankar, S. Devasahayam

An experimental study of the particle charac¬teristics of the magnesium carbonate crystals formed by the reaction between magnesium chloride and sodium bicarbon¬ate at different temperatures is described. The rate of growth of magnesium carbonate crystals for any constant tempera¬ture is established, and this rate of growth is related to the degree of supersaturation at the given temperature. The activation energy calculated using empirical constants de¬rived from the relationship between the crystal growth rate and supersaturation, is indicative of a surface-reaction mechanism.

Jan 1, 1996

By A. W. Deurbrouck, W. W. Agey

Introduction The modern wet concentrating table is a rectangular or rhomboid shaped normally rimed-deck operated in essentially a horizontal plane (Fig. 23). A drive mechanism imparts a differential motion to the deck along its long axis while water flows by gravity along the short axis. Tables are currently employed for processing large tonnages of coal and lesser tonnages of barite, beach sands, chrome, glass sand, garnet, iron, manganese, mica, phosphate, potash, tantalum, tin, tita-

Jan 1, 1985

By C. P. Parsons

Caliper logging is a practice of measuring the variations in the diameter of the open hole in a well. This information is useful for many purposes, among which are: Determining the volumetric capacity of the portion of open hole to be cemented; the amount of gravel to be used for gravel-packing a well; the size and location of seat for a packer to be placed in a well; studying the effects of nitroglycerin shots; studying the effects of acidizing; studying the cause of drill-pipe failures; studying drilling technique; geological correlations. This is a new practice in oil fields and is eliminating considerable guesswork. Introduction Caliper logging of the open hole in oil wells, recently introduced and now showing initial results in many sections of the country, is providing information that is filling a long-felt need in oil-well cementing and in numerous other oil-field practices. Briefly, it measures the variations in diameter, of the open hole in a well. This direct physical measurement of the strati-graphic profile has considerable value for subsurface interpretations by the geologist, engineer, driller and others charged with the responsibility of properly completing and repairing oil and gas wells. The caliper shown in Fig. I is run into a well in closed position. The four arms are released when logging is to start. These arms are independent of each other. As the calipers are pulled upward through the open hole, the arms are like nimble fingers feeling the changing profile of the hole. This mechanical action is in turn converted into an electrical circuit, which is connected to a recording mechanism at the surface. a. Lowered into well in closed position. b. Arms released. Readings are made while caliper travels upward. Direct recording is made at surface, in inches. The recording of the diameter of the hole is directly in inches.

Jan 1, 1943

By Lon D. Santis

The Code of Federal Regulations Title 30, Parts 56, 57, 75, and 77 require that detonators and explosives be separated by four inches of hardwood or equivalents when transported together in mines. This standard was developed to protect the explosives from initiation by the more sensitive detonators. The research reported here is an attempt to quantify the fire protection offered by four inches of red oak and other materials. Boxes with a volume of 6.75 cubic feet were made from four-inch thick rough green oak (RGO), two-inch thick RGO plied, two-inch thick #1 common (dried) red oak plied, and a metal/plywood composite. These and boxes meeting the Institute of Makers of Explosives' (IME) Safety Library Publication No. 22 were tested in bonfires. The boxes were instrumented with thermocouples, filled with detonators, and placed over a kerosene fire imparting about 16 kilowatts per square meter heat flux for up to 3 hours.

Jan 1, 1997

By D. N. Collins, J. R. Stevens

New expressions in the technical assessment of mineral concentration processes have been defined as Concentration Efficiency: Concentration Index: where h is the percentage of head grade; c, percentage of concentrate grade; maximum percentage of concentrate grade obtainable at 100 pct recovery; and R, percentage of recovery. In developing these expressions, the basic requirements for the technical assessment of concentration operations have been defined and the various expressions suggested by others for asses-sing the results of such operations reviewed and criticized. The derived expression for E, depends on a simple combination of recovery (R) and a new term selectivity (s), where S is (c-h)/(c,,, -h), by definition. Limitations of the new expressions are discussed and examples given of applications to concentration operations. It is also shown that the formulae for E, and I, can be applied to scatter diagrams, multi-component systems, size-assay analyses, and classification data. Many methods of quantifying concentrating operations have been proposed. These include direct presentation of weights and assays together with the derived data for other items such as ratio of concentration, recovery, rejection losses, and enrichment ratio. These terms are now accepted mineral dressing nomenclature, and in the assessment of the results of concentration processes, concentrate grade and recovery are together the most widely accepted measures of concentration efficiency. For practical purposes when the concentrate grade is equal to or greater than a predetermined acceptable value, test or operation results may be assessed by the recovery figures alone. Similarly when recovery is within specification, the operation can be assessed by concentrate grade. The ultimate assessment and selection of a concentration operation is—admittedly with a few ex-ceptions—a matter of economics. There is however an intermediate stage in laboratory and pilot plant testing when evaluations must be made without the assistance of an economic yardstick. Numerous techniques are employed to facilitate such evaluations among which may be mentioned graphical plots of grade vs recovery, cumulative weight vs cumulative recovery, scatter diagrams, etc. The desirability of combining metallurgical results and product weights and assays into a single value has been recognized and discussed by many workers1-" with the resultant suggestion and use of such terms as Metallurgical Efficiency ,' Summation Index,' Selectivity Index,'- and Absolute Efficiency B None of these expressions completely satisfies all the requirements of a selectivity or efficiency formula and it is proposed in this report to define the terms, relating to the technical efficiency of a concentrating operation, concentration index and concentration efficiency. Examples are given of their application and a comparison is made of their use in relation to other formulae. All product grades in this paper will be referred to in terms of mineral percentages and a list of symbols is given in Table I. CONSIDERATION OF EXISTING FORMULAE A number of the existing efficiency and index terms used in quantifying concentrating operations are considered below. Metallurgical Efficiency:

Jan 1, 1961

By A. V. Deforest, A. R. Anderson, C. W. MacGregor

One of the important problems in the design of structures and machine parts subjected to rapidly applied loads is the determination of the strength and ductility of the material itself under such conditions. Realizing the need for such information, many investigations have been carried out in the past. Most of these experiments have been made using notched bars in bending either with the Charpy or Izod impact machine. While yielding valuable data on the effect of notches in the energy absorption of the material and on the condition of heat-treatment, this form of test does not lend itself readily to a determination of fundamental stress-strain relations. For this and other reasons, more attention has been paid recently to the tension impact test. An extensive literature already exists on the subject and only those investigations somewhat closely related to the present paper will be mentioned. For a more comprehensive list, the reader is referred to the Symposium on Impact Testing or the A.S.T.M., 1938. The work of Mann.' Clark and Dätwyler,2 Nádai and Manjoine,3 Winlock and Leiter,4 Deutler,5 and Brinkmann,6 however, deserves especial mention. In most of the previous investigations on the subject, when stress-strain relations were obtained under high rates of loading, it was the common procedure to determine stresses based on the original area and strains based on the original length. Stress-strain curves were then constructed by P ALo plotting So = 1/A0 as a function of eo = ALr,o where A0 and Lo refer to the original area and gauge length, respectively. At present there exists a paucity of true stress-strain data in the impact problem. The advantages of constructing so-called true stress-strain curves in order to reveal the fundamental physical properties of the material for the tension test were discussed recently by one of the authors.7'8 It was shown that the true physical behavior of the material in the tension test could best be represented P by plotting the average true stress, S = 2P as a function of 6 = q' = log —r = log ~9L where P, A, L, S, E, and q' refer to the load, the cross-sectioned area while the load P is applied, the actual gauge length, the average true stress, the true strain and true reduction in area, respectively. Besides giving a better physical representation, the method has certain additional advantages in that the stress-strain curve so plotted becomes a straight line from the maximin load point to fracture. The construction of such curves, however, while comparatively simple for the slow rates of loading customarily used in the tension test, presents certain dificulties for tensile impact in that both loads and diameters are required throughout the test. The continuous measurement of test-piece diameters to fracture under impact conditions offers considerable experimental difficulty. In order to make it feasible to

Jan 1, 1942

By D. Harrington

"While distribution of air currents to working faces is a necessity in coal mines, especially those having explosive gas, advancing faces in metal mines rarely have circulating air other than the ordinarily inadequate amount supplied through the compressed air system. Even where comparatively large quantities of air pass through main mine shafts and levels. whether the circulation is actuated by fans or by natural ventilation, only occasionally can a metal mine be found where any considerable percentage of the ""blind ends"" has circulating air of sufficient velocity to be measured by an anemometer or even be discerned by deflection of flame of candle, or of acetylene lamp; and unfortunately these ""blind ends"" include nearly all of the places from which rock is taken.During several years study of metal-mine ventilation in various mining districts of the United States, it has been found that in some mines many of the workers in ""blind ends"" practically continually breathe air with 0.02 to 0.04 per cent of CO gas from unremoved fumes from explosives; in other mines CO2 chiefly from timber decay and breathing of men, is so high that a candle will not burn though usually the acetylene lamp will, hence oxygen is below 17 per cent but above 12 per cent; in some regions CO2 from strata fills the entire mine forcing cessation of work; in other mines in dead ends, gases such as nitrogen, H2S, SO2, etc., are found under some conditions. In many regions with hot rock or water (especially in deep workings) men in blind ends must work with little or no circulation, in air above SO degrees F. and even above 90 degrees, relative humidity only too frequently being around 100 per cent; in other regions workers in blind ends in practically ""dead"" air must continually breathe enormous quantities of finely divided rock dusts. All of the above conditions are decidedly harmful to health and prevent the worker from delivering anything approaching an adequate quantity of work, and in addition, some of these conditions have direct or indirect effect in bringing about definite increase of accidents; all of the above mentioned bad conditions in ""blind ends"" in metal mines as well as their ill effects, are remediable by providing at those places adequate quantities of fresh circulating air."

Nov 1, 1923

By Galen Clevenger

THE losses of gold and silver occurring during the conversion of the precipitate, resulting from the cyanide process, into bullion may occur in two ways: first, there may be mechanical losses during the handling of the precipitate up to the time that it is charged into the melting furnace; and second, there may be losses after the precipitate reaches the melting furnace. Much of the loss during the handling of the pre-cipitate can be eliminated, and in fact, in modern plants this loss is known to be very small; particularly since preliminary acid treatment of the precipitate with the attendant extra operations has been abandoned in all but certain plants where gold predominates and this extra step is still deemed necessary. The losses in the melting furnace are from dusting and volatilization; losses in the furnace bottom and linings; floor sweepings; and slag and matte. The gold and silver in the: products which do not: go out of the flue are readily recoverable by standard methods, and while there may be considerable gold and silver tied up at times, the ultimate loss with careful "work should be small. The losses resulting from volatilization and dusting in connection with the melting of the silver slime from copper refineries have been determined by standard methods, and the possible recovery: definitely estab-lished through the installation and operation of electro-static precipitation units. This subject has not been thoroughly investigated in connection with the melting of`. cyanide precipitate; at least, there are no published accounts of such tests. Experiments have been made in the past to determine melting losses by weighing and assaying the precipitate, but this method gives results which are uncertain on account of the difficulty of accurately sampling and assaying cyanide precipitate. Attempts to ascertain these losses by bubbling a measured sample of the gas through cyanide solution or, other absorbent have likewise failed to give depend-able results.

Jan 1, 1922

By Sam S. Taylor, H. M. Smith

"INTRODUCTION In most oil fields, natural gas is the major source of energy causing flow of oil to the well. The amount of gas Produced with the oil generally exceeds actual energy requirements, so that in time the gas reserve of the field becomes seriously depleted and the oil production must be stimulated by some auxiliary means. One of these is to repressure the oil formation with natural gas; or, where a gas supply is not available, often air is used.Although P.ir is a Cheap and convenient repressuring medium, its use sometimes is attended with several disadvantages. First, the return air-gas mixture decreases rapidly in fuel value, often until it can be used no longer as a source of power. At the same time, explosive mixtures may result if recycling is used, causing hazards to life and equipment. Second, some fields experience considerable trouble with the formation of emulsions which become increasingly difficult to treat. Although there is no definite proof that air repressuring always causes these emulsions, many operators are convinced that this is the case. The Petroleum Experiment Station of the United States Bureau of Mines at Bartlesville, Okla., has been interested in problems connected with air-repressuring for a number of years. Some time was spent in studying the so-called ""bad gas""--return,mixture of low fuel value. However, it appeared impossible to attack the problem successfully from this angle, and an approach was made through a laboratory--scale study of direct oxidation of crude oil."

May 1, 1934

By Florian Kongoli

While calcium ferrite slags have been successfully used in continuous copper converting for the last 30 years, ferrous calcium silicate slag was proposed about 8 years ago as an additional alternative for copper smelting. Although both slags are normal extensions of each other their phase relations have not been completely clarified. In this paper the liquidus relations of both slags have been quantified at various areas that cover both of them. The existing experimental data have been first reviewed and discussed in relation to the solidification procedure. An original physical model is then used to predict various diagrams of the liquidus surface of both slags. It is shown that the ternary liquidus diagrams normally used for FeOx-SiO2-CaO system are not suitable for industrial slags. The new model diagrams of Fe/CaO versus SiO2 and Fe/SiO2 versus CaO as well as Fe/CaO versus Temperature and Fe/SiO2 versus temperature are proven to be much more convenient for ferrite and ferrous calcium silicate slags. Based on these diagrams the effect of SiO2 and CaO on the melting temperature is quantified. The effect of Cu2O is also quantified through the model. Some Fe/CaO versus Cu2O and Fe/SiO2versus CaO at various copper contents are predicted and the results show good agreement with the experimental data. It is also shown that in the presence of liquid copper, Cu2O is dissolved in the slag depending on the oxidation degree of the system and might lower the liquidus temperature. Some discussions are also presented taking into account plant observations and important conclusions are drawn for copper smelting and converting

Jan 1, 2006

Alpha Portland Cement Co.'s mining operations at Manheim W. Va., produce 750,000 bbl of limestone yearly, averaging 2200 bbl per working day. Thirteen parallel entries have been driven to date, each almost 30 ft high and about 45 ft wide, extending back 5000 ft to the working faces. Pitch of the seam from the lowest to the highest entries is steep enough to provide excellent year- round natural ventilation, and this, together with the size of the entries and a good bottom, has allowed face crews to drive right up to the working areas in the family car.

Oct 1, 1956

By I Mason, G Turner, J Hargreaves

One of the key objectives in production from any mine is the minimisation of ore loss and dilution. This can only be achieved when the distribution of ore within the mine is known. The distribution of ore is usually evaluated from a combination of drill hole information and underground mapping data. Three-dimensional models of the ore distribution are then constructed by interpolating grades, contact locations and confirming these estimates through mapping. While the interpolation procedure can incorporate an understanding of the local geological conditions, it is an approximation and thus susceptible to some degree of ore loss or dilution. Naturally, such problems increase in areas of sparse geologic information or greater geologic complexity. Borehole radar offers an approach to decrease the interpolative aspects of modelling by providing a continuous image of some ore contacts. Borehole radar works by building a two-dimensional image of an ore contact from radio waves bounced off the contact from closely spaced positions along a borehole. This image can be imported into Datamine (or a similar design package) and incorporated into geological models of a given ore block. The results of a trial survey from the Mariners nickel mine at Kambalda are presented to illustrate the improved level of detail and accuracy that can be achieved through the incorporation of borehole radar into orebody delineation practice. Once implemented on a large-scale this technique has the potential to greatly increase the cost-effectiveness of long hole stoping at Kambalda, through increased ore recovery and reduced dilution.

Jan 1, 2000

By P. E. Nielsen, T. L. Loga, B. B. Mauko

A numerical model is presented which simulates the dynamic fracturing process for a circular geometry fracture in a uniform stress medium. The dependence of crack aperture and net pressure in the crack upon various dominant parameters of the fracturing process is discussed. An analysis of a 75% nitrogen foam fracture in a coal seam at 5600 feet (1707 m) is also presented. The analysis is based upon the discussed parametric trends, the job records of treatment parameters, and a Nolte plot of net downhole pressure. It is interpreted that fracturing with water, in pre-foam fracture pump tests, resulted in significant fracture height growth. However, the subsequent foam fracture had reduced height growth due to the high effective viscosity of the foam and due to the higher magnitudes of elastic modulus and stress in the bounding rock strata with respect to the coal.

Jan 1, 1986

By R. W. Utley

The purpose of this study was to seek and evaluate possible relationships between the composition of coal refuse, as expressed by washability data, and factors affecting the product ion of a lightweight aggregate from refuse by bloating. The study was related to an intense program in the Department of Mineral Preparation at the Pennsylvania State University to study the possible elimination of air pollution from coal refuse fires by producing a low- carbon secondary refuse. Another phase of this program is considering possible uses of such a secondary refuse. Thus one study was to determine if a lightweight aggregate could be produced from this new refuse material and what effect the nature of refuse beneficiation would have upon the characteristics of a commercial aggregate product.

Jan 1, 1965

By Juan H. Rojas

The Chuquicamata mining and metallurgical complex is the main division of CODELCO-CHILE. Its comparative advantage in the world of primary copper producers had deteriorated severely and, consequently, its top management launched an extensive modernization plan. This paper shows how Chuquicamata recovered its position as a low-cost copper producer and is now well positioned to face the end of this century, as far as competitiveness is concerned. It also shows the company's vision for the )(XI century. Given the volume of its ore reserves, one possibility is expanding the sulfide production line capacity, while in the case of the oxide production line, ore reserves are limited so that there is a need to maximize the effectiveness of both organization and technology use. A final consideration has to do with the balance of supply and demand. Most observers of the copper market agree that supply is growing faster than demand. On the other hand, copper is facing severe environmental problems, especially in the piping business, plus the usual threat of substitution. Nevertheless, copper producers are making very weak efforts to defend the market and increase copper consumption through the promotion of new uses of the metal. This issue is crucial and must be considered if copper producers want to maintain a profitable market.

Jan 1, 1998

By Roque Benavides

El artículo describe el enfoque de minería comprometida con el desarrollo sostenible de Compañía de Minas Buenaventura, el mismo que está basado en cuatro importantes pilares: fortalecer las actividades tradicionales a las que se dedican las comunidades vecinas; impulsar con ellas una “hermandad del agua” para obtener y compartir este valioso recurso; fortalecer la educación y la salud como estrategia para potenciar capacidades individuales y colectivas; y velar por la vida de sus colaboradores, aspecto en el cual la innovación y la tecnología juegan un rol muy importante. Adicionalmente, el autor destaca el rol solidario y reactivador de la industria minera en el marco de la emergencia nacional por COVID -19.

Jul 30, 2020

By Zhonglin Ye, Yifeng Shi

"This paper has outlined forms of Au & Ag losses in copper smelting process and methods for increasing Au & Ag recovery, analyzed factors influencing Au & Ag recovery in copper converting process, presented Au & Ag behavior in copper electrorefining process, and reviewed effect of current density/electrolyte circulation rate during electrolysis and surface finish of cathode on Au & Ag losses. Measures and research direction for decreasing Au & Ag losses in electrolysis have also been introduced. Based on Au & Ag behavior in copper electrorefining process and previous studies by others, new approach for increasing Au & Ag recovery in copper smelter has been discussed. And brief comparison has made between continued multiplication method and equilibrium method application in the case of calculation of Au & Ag recovery in copper smelter.IntroductionAs gold and silver are the major by-products from copper smelting process, efficient Au & Ag recovery has become one of the key approaches for copper producers to increase economic efficiency. With similar physicochemical properties, Cu, Au and Ag belong to the first subgroup of elements in the same periodic table. Au and Ag will be enriched into Cu phase firstly when both matte-slag phase and copper-matte phase appear in copper smelting process. However, great changes have taken place in Au & Ag proportions into individual phase due to changes of physicochemical conditions in each smelting process. Metallurgists at home and abroad have carried out a great deal of pilot plant tests and laboratory tests in order to increase Au & Ag the former Soviet Union with regard to Au & Ag losses in copper smelting process in the 1970s and 1980s, and he proposed solutions to increase Au & Ag recovery in copper metallurgical plants. As more than 20 years passed, Jingchun Lu's paper, Discussion on Increasing Au & Ag Recovery in Copper Smelting System, remains as a literature of the most comprehensive study. Based on Jingchun Lu's literature, the authors of this paper discussed new approaches to increase Au & Ag recovery in copper metallurgical plants with combination of many researches done by other researchers for over 20 years."

Jan 1, 2013

By G. R. S. Smith

In any filtration, it is primarily the filter medium (cloth) and cake filtering properties that control the type of filtration equipment used and filtration conditions. The advent of new types of filter cloths, such as the membrane cloth discussed in this paper, can result in significant changes in filtration techniques and areas of application for filtration. For many suspensions, for instance, conventional filtration is uneconomic compared to gravity separation or not filtering at all (as with product recovery from dilute streams) because the solids are very fine, are hard to retain and build up filter pressure rapidly, and once retained are hard to remove. As a result of the developments discussed here, this is no longer the case. This technique and the use of the membrane filter cloth is well established. This filtration is currently being used for white liquor filtration in twenty-four mills worldwide in the chemical recovery step of the kraft process for producing paper pulp where it is replacing gravity thickeners in new plants. Filters up to 1000 sq. ft. (100 sq. meters) are filtering large volumes of solids from hot caustic solutions. The filtration materials and techniques discussed in this paper open the way to new methods and applications for filtration in the mining industry. It is not the intention of this paper to give a vigorous analysis of the different separations, but to outline some of the ways in which this filtration technique might be used in the mining industry.

Jan 1, 1989

This Volume documents the Phase 111 effort on the Seismic Detection and Location of Isolated Miners on Contract H0122026 undertaken during the fall of 1972 by a task team composed of ADL staff and several seismic consultants. The team was assembled specifically to work together on complementary tasks, at an accelerated level of effort for four months, to meet the Bureau of Mines' time schedule for obtaining independent, objective, technical judgments regarding seismic methods and systems for detecting and locating isolated miners. The impetus for this work resulted from a compilation and analysis, during the first half of 1972, of new experimental data obtained from a series of in-mine field tests conducted by Westinghouse Corp .+ using the CMRSS* interim seismic location system. The Bureau of Mines took advantage of the availability of these new data to reassess the potential and limitations of various seismic methods and systems, and to direct its seismic system improvement program accordingly. ADL assisted the Bureau in this reassessment by drawing on the skills of seismic consultants from industry, universities and government, to supplement the skills of the ADL project team. The consultants were principal resources of broadly-based and detailed technical expertise in the areas of seismic signal-source and signal-propagation characteristics, natural and cultural seismic noise, seismic sensors and field instrumentation, seismic signal and data processing for detection and location, and overall seismic system utilization in the field under operational emergency conditions. Specifically, the participating consultants were: F. Crowley, Air Force Cambridge Research Laboratories ; W. Dean, Teledyne Geotech, Alexandria Laboratories; R. Greenfield, Pennsylvania State University; J. Kuo, Columbia University; D. Peters and R. Crosson, University of Washington; and F. Pilotte, U.S. VELA Seismological Center. The principal ADL participants were J. Ginty, R. Lagace, M. Roetter, and R. Spencer.

Jan 1, 1974

By Franklin R. Carpenter

In area, the Black Hills are about equal to the State of Connecticut. As the accompanying geological map indicates, they exhibit in the main a simple structure, presenting a central mass of granite and Archæan rocks, on all sides of which the later sedimentary rocks dip

Jan 1, 1889