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By T. Egleston

SOME months ago samples of black oxide of copper and of pig copper from Colorado were sent to me to examine for arsenic and

Jan 1, 1882

By David A. Bacca

Hydraulically powered submersible borehole dewatering pumps and emulsion/ANFO blends evolved at about the same time and for the same reasons. Mining operators needed safe, efficient dewatering systems and water resistant products.

Jan 1, 1994

By David Regalado

En los últimos años se presentaron pérdidas en el proceso de ejecución de chimeneas principales (por derrumbes y rehabilitaciones) en Unidad Minera Orcopampa. Este artículo muestra cómo se viene superando el problema con un proyecto basado en el conocimiento de la geología del terreno y la aplicación de conceptos y herramientas de geomecánica, de forma tal que la ejecución de una chimenea principal —bien sea para ventilación con Raise Bore o Raise Climber (Alimak)— cumpla su función y perdure a través del tiempo.

Feb 28, 2019

By J. M. Dean, R. L. Grayson, R. D. Begley, G. L. Winn

Evidence has accumulated indicating that cultural change toward safer workplace behaviors is beginning to occur systematically in the coal industry. Through a range of programmatic mining company successes, enforcement and litigative actions, economic responses to competition and integrated efforts by federal and state agencies, a broader participation of safety and training professionals is being achieved to address prioritized workplace problems at mines. Small steps in workplace-related improvements have been realized already, but the trends in industry safety statistics, coupled with focused programmatic initiatives, indicate that more definitive and systematic steps are occurring to improve safe behavior in the workplace routinely.

Jan 1, 1998

By Brian D. Bornhold

A comprehensive multi-disciplinary marine geological survey of northwestern Graham Island, Queen Charlotte Islands, British Columbia, Canada was conducted by Offshore Survey and Positioning Services Ltd. of Vancouver, B.C. on behalf of the Geological Survey of Canada; Energy, Mines & Resources Canada, Pacific Geoscience Centre, Sidney, B.C. Canada during October 1984 and July 1985. The aim of the survey was to map both the surficial geology and geomorphology in order to identify and evaluate the nature of the nearshore sedimentation and recent tectonics including stability (slumps and scarps) seafloor faults (frequency and displacements) and both the classification and consistency of soil type boundaries and properties. Data was acquired by utilizing conventional indirect applied marine geophysical techniques including side scan sonar, precision echo sounding and complimentary soil sampling. During October 1984 a total of 320 line kilometres of data including 180 soil samples were acquired. During July 1985 a total of 300 line kilometres of data were acquired including 150 soil samples.

Jan 1, 1985

By Robert A. Colten, Frederick C. Hull, Robert F. Mehl

It is known that pearlite forms from austenite by a process of nucleation and growth, and that the rate of formation of pearlite may be described by a rate of nucleation and a rate of growth.l,2 The manner in which these two quantities operate to produce the observed isothermal reaction curve has been analyzed in a paper published in I939.3 Two types of process were described: (I) that in which nucleation occurs at the grain boundaries of the parent phase, with the nodules growing toward the centers of the grains, initially as hemispheres and then after impingement as roughly radial-columnar structures; and (2) that in which nucleation occurs generally, with the nodules growing to full spheres until impingement with other growing nodules restricts growth. Both cases are met in the formation of pearlite from austenite (Fig. I);2,4 the former, occurring near the knee of the S-curve, has been named "grain-boundary transformation," and the latter, occurring at temperatures near Ael, has been named "group-nodule transformation." In developing our knowledge of the factors that determine the rate of formation of pearlite from austenite, it is important1,2 to obtain data on the rate of nucleation and the rate of growth of pearlite. Such data, when obtained near the knee of the S-curve, will furnish information of use in understanding the factors that affect hardenabil-ity; when obtained at higher temperatures, such data will be useful in understanding the behavior of steels that during heat-treatment react to pearlite.2 It is the purpose of this paper to present data on the rate of nucleation and the rate of growth of pearlite in dependence upon composition, grain size, temperature, and the degree of homogeneity of the parent austenite. The studies are restricted chiefly to plain carbon commercial steels." Previous Data on Rate of nucleation and rate of Growth Data on the rate of nucleation and the rate of growth of pearlite have been published by Scheil and Lange-Weise,5 by Mirkin and Blanter,6,7 by Meh1,l and by Dorn, De Garmo and Flanigan.2, It is difficult to interpret the data, for in most cases too little information is given on austenitizing temperatures and times, the state of homogeneity of the austenite (presence or absence of carbide, etc.), austenite grain size, and mode of formation of pearlite at the temperatures given. Except for the approximations of Mehl and the work of Dorn, austenite grain size was disregarded, though it is well known

Jan 1, 1942

By Louise Reber

THE town of Jerome is located in Yavapai County in north central Arizona. It has a population of over 6000 people and the two important mines of the district, the United Verde and the United Verde Extension, lie almost within its limits. Perched high on the southwest side of the Verde Valley, at elevations of 4800 and 5500 ft.. (1463 and 1676 m.), both mines have long tunnels from their lower levels through which ore is hauled to their respective smelters. The two smelter towns of Clarkdale and Verde, out in. the center of the valley and about 2000 ft. (609 m.) below, form part of the wide panorama that meets the eye at Jerome. This panorama and the topographic and surface features and the geologic formations are shown in a separate pamphlet. In the vicinity of Jerome, the great southern escarpment of the Arizona plateau forms the northeast side of the Verde valley. The general level of this escarpment, or "the rim" as it is called, is about 4000 ft. above the Verde River. A corresponding elevation is reached only by the, highest parts of the Black Hills, which bound the valley to the southwest. The two lava-capped mesas, known as Mingus and Woodschute Mountains, form the culmination of the Black Hills. That part of the old Black Hills mining district which lies between their crests -and the Verde River is now known as the Jerome or Verde copper district. However, if the smelters are not included, a strip about 7 mi. long and 3 mi. wide (11 by 5 km.) embraces practically all the properties belonging to the Jerome district. This strip lies parallel to and along the side of the Verde valley from about First View, 2 mi. northwest of Jerome, to the neighborhood of Allen Spring, near the south end of Mingus. Mountain. The rank of the district in copper production, as well as features of peculiar geologic interest in connection with the ore occurrences, entitle the district to much more consideration than it has received in the literature of copper mining. Arizona stands preeminent as a copper-producing state. In 1918, it produced four-tenths of the total amount produced in the United States, and nearly equaled the, combined production of its three chief competitors, Montana, Michigan, and Utah. The production of the Jerome district places it in the sixth place among the copper

Jan 8, 1920

By C. K. Leith

The question as to what grades of ore it pays to conserve for the future, and the valuation of low-grade reserves, are becoming immediate and definite as applied to the individual ore deposits, and seems to call for some sort of quantitative answer.

Jan 1, 1915

Organization Place Date 1917 American Institute of Architects Philadelphia., Pa. Dec. 26-29 American Society of Mechanical Engineers New York City. Dec. 4-7 American Mining Congress State Chapter Phoenix, Ariz. Dec. 26-29 1918 American Society of Civil Engineers New York, N. Y. Jan. 22-25 American Institute of Mining Engineers New York, N. Y. Feb. 18-21

Jan 12, 1917

By M. Karmis

"The process of coal mining, as indeed of the mining of any stratified mineral, is inevitably followed by some degree of sinking of the superjacent strata and consequently of the surface." Royal Commission on Mining Subsidence, Second and Final Report, London, 1927. INTRODUCTION The above statement was used to describe mining subsidence in the classic report of the "Royal Commission on Mining Subsidence," published in 1927. In fact, this phenomenon has been recognized in Britain since the early fifteenth century, as revealed from court records of disputes and litigations related to property damage above mine workings (Shadbolt, 1978). The first attempts to investigate and analyze the mechanisms associated with mining subsidence, however, date back to the 1800's and were pursued by Belgian Engineers. This research effort was initiated as a result of the widespread movements and subsequent structural damage suffered by the City of Liege in the 1820's. The most notable achievement of the Belgian school of that era was he publication of Gonot's treatise "Loie de la Normal" in 1871 (Gongt, 1871).

Jan 1, 1982

By Upfold RW, Velzeboer MD

An underground mine fire will influence the ventilation equilibrium in several ways which results in a redistribution of the ventilating quantities and pressures throughout the whole mine. The ventilation carries the combustion products which constitute the greatest danger of mine fires through the mine and provides the oxygen on which the intensity of the fire depends. However, as a result of the ventilat- ion disturbances created by the fire, changes in airflow patterns can take place which are not always obvious, especially when the mine is being served by several fans. The use of com- puter simulation techniques allow for the likely effects to be tested and the different ventilation options to be evaluated as an integral part of the overall emergency/rescue planning and control procedures.

Jan 1, 1981

By Lindbeck K

The mining industry in Western Australia is a large sector of the WA economy providing $12 billion (1993) of the export income for the State. Historically, mining in WA developed from traditional prospecting in the late-1880s leading to major underground operations by the turn of the century. Large open pits were developed in WA following World War II and became increasingly common since the gold boom of the 1980s. With the development of the open pits has been concomitant evolution of mining legislation, principally the Mining Acts of 1904 and 1978, which has been also accompanied by a practical evolution of the administrative system within the Department of Minerals and Energy. The mining industry has recognised the need for sound environmental management at mine sites, taking up the challenge and becoming a world leader in rehabilitation techniques. Any environmental management program in the industry has three stages: approval by government; management by the industry; and return to the State in an environmentally acceptable condition. The WA environmental requirements, procedures and industry performance in these three stages are discussed.

Jan 1, 1994

By A. Gene Collins

Potassium, lithium, strontium, barium, and manganese are present in many oilfield brines, None of them except barium is determined routinely in brine analyses. Therefore, sensitive and accurate flame-spectrophotometric methods were developed. Potassium, lithium, and strontium were determined by a standard-addition technique in ethyl alcohol solutions. Barium and manganese were determined in ethyl alcohol and normal propyl solutions, respectively, after interfering substances were removed.

Jan 1, 1962

Jan 1, 1935

By A. E. Back, S. F. Ravitz

When manganese ores are leached with sulphur dioxide, a large part of any zinc in the ore usually is extracted with the manganese.1 In the dithionate process,2,3 in which the manganese ore is leached with dilute sulphur dioxide gas and the manganese is subsequently precipitated by adding lime to the pregnant solution, the zinc is precipitated with the manganese. These facts suggested the possibility of applying the dithionate process to the recovery of zinc from oxidized ores or calcined sulphide concentrates. Accordingly, an investigation was begun, and preliminary tests were made on several ores and concentrates. The results were encouraging, but the need to devote available funds and personnel to other projects made it necessary to drop the work before the various factors involved in the process could be studied in detail. A brief mention of the process,4 however, elicited a number of inquiries, so that it appeared desirable to report the results of the preliminary work. The dithionate process as applied to zinc may be summarized briefly as follows: The ore or calcined concentrate is leached with dilute SO2 gas to dissolve the zinc, largely as zinc sulphate, in accordance with the following equation in which [ZnO] represents the "oxide zinc" in the ore or calcine: [ZnO] + SO2(g) + 1/2 O2 = Zn++SO4— [1] If, in the leaching step, the ore or calcine is suspended in calcium dithionate solution, the sulphate ion, as it is formed, is precipitated immediately as calcium sulphate, which is subsequently filtered off with the insoluble ore residue: Zn++SO4— + Ca++S2O6— = CaSO4(s) + Zn++S2O6- [2] An alternative procedure is to suspend the ore in water, filter off the insoluble ore residue after leaching, add calcium dithionate to the resulting zinc sulphate solution, and then filter off the calcium sulphate precipitate. In either event the zinc is obtained in the form of a pregnant solution of zinc dithionate, from which it can be precipitated as relatively pure zinc hydroxide by adding milk of lime: Zn++S2O6— + Ca(OH), = Zn(OH)2(s) + Ca++S2O6- [3] The zinc hydroxide precipitate is calcined to form the final zinc oxide product: Zn(OH)2 = ZnO(s) + H2O(g) [4] Theoretically the process is completely cyclic with respect to dithionate ion, the calcium dithionate required for reaction 2 being replaced by that formed in reaction 3. In practice, of course, small amounts of dithionate would be lost in the various filter cakes, depending on the economic washing limits. In the leaching step, however, some of the SO2 is oxidized to dithionale instead of sulphate, accord- ing to the following overall reaction: ZnO + 2SO2(g) + 1/2 O2(g) = Zn++S2O6-, [5] so that the dithionate losses are made up, at least in part. Ores and Concentrates Tested The analyses of the ores and concentrates tested are summarized in Table 1, which also includes the analyses of the calcines produced from the concentrates. The concentrates were roasted in a laboratory muffle furnace at the temperatures indicated until evolution of SO2 could no longer be detected; shallow clay dishes ordinarily were used; but calcines 2a and 2c were prepared in iron dishes, with the result that these two calcines were badly contaminated with iron scale. The "complex" concentrate, sample 1, consisted essentially of sphalerite grains containing inclusions of pyrite and other sulphide minerals too minute to be liberated by grinding within economic limits. In the " marmatitic" concentrate, sample 2, the iron was present largely as marmatite (that is, as iron sulphide in solid solution in zinc sulphide) rather than as pyrite inclusions. The zinc was present largely as the carbonate in the two "oxidized" ores, samples 3 and 4, and as the silicate in the "willemite" ore, sample 5. Leaching Tests The leaching cell was a 3-liter glass beaker placed in an electrically heated water bath manually controlled to maintain a temperature of 35°C in the leach slurry. The slurry was agitated by means of a flat paddle-type stirrer

Jan 1, 1950

By S H. Algie, D P. Taplin, S G. Doig

"Suboptimal performance of clusters of hydrocyclones (cyclones), relative to the performance of the individual cyclones that comprise the cluster, is a common phenomenon. The primary cause is well known: uneven distribution of the slurry feed into the individual cyclones. The direct result of uneven distribution is that each cyclone in a cluster performs somewhat differently. Hence, some, if not all, of them do not work at their intended operating points, and the classification is not as sharp as intended. The impact on grade, recovery and milling efficiency will vary depending on the duty of the processing circuit, but the most immediately apparent consequence of uneven distribution is a difference in wear rates in the individual cyclones; this exacerbates the problems of unequal performance of the individual cyclones. In severe cases, and as differential wear proceeds, flows from the individual cyclones may become visibly different. Uneven distribution, once the phenomenon was identified, was seen to be a significant issue in the high-solids hydrocyclone cluster in the ball mill recycle section of Evolution Mining’s Edna May Operation (EMO, Westonia, Western Australia) gold processing plant. In 2012, a FloCEP® hydrocyclone feed distributor system was installed to alleviate the problem. Over the next four years of operation, this innovation has proven its value in the metallurgical and maintenance areas. Individual cyclones now wear at the same rate, greatly reducing the need for operator intervention, as well as increasing overall plant availability through minimising unplanned maintenance. The costs of the installation can be justified by savings in maintenance alone, though the greatest value, as is described in this paper, is in allowing the plant to produce consistently closer to its operational design limits. The FloCEP® system is a low maintenance, readily installed retrofit, based on two patented devices that are combined with complementary proprietary design methodology allowing customisation for specific flow rates and slurry particle properties. Together, these devices produce and distribute a pseudo-homogenous slurry flow without moving parts.Citation:Taplin, D P, Doig, S G and Algie, S H, 2016. Experience with FloCEP® Slurry Flow Conditioning at Evolution Mining's Edna May Operation, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 251–260 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By R. N. Chakravorty

It is well established that coal can react with oxygen in air at ambient temperature and as a result heat is produced. If the heat is not fully dissipated the temperature of the coal mass will increase, thereby enhancing the rate of oxidation with a greater production of heat. If this phenomena continues, the coal mass can ignite under favourable heat accumulation conditions. A number of mine fires are caused each year due to this phenomena, commonly known as spontaneous combustion. The early detection of spontaneous combustion is of prime importance to mining engineers since any fire which could be detected at an early stage may save the mine from considerable damage and subsequent loss of production. Obviously, there is no single general criteria by which one can assess whether the under- ground mining of a coal seam will result in liability to spontaneous combustion. This has made it imperative to develop systems for the early detection of heating and to follow its development. In recent years considerable advances have been made in the design and development of methods for the early detection of spontaneous combustion. The Mining Research Laboratories (CANMET) is presently investigating the problem of spontaneous combustion in coal mines with Kaiser Resources Ltd. at their hydraulic mine at Sparwood, B.C. on a co-operative basis, and some of the work was described earlier in the Canadian Institute of Mining & Metallurgy Bulletin (1,Z). This paper summarizes and updates the work done by CANMET on the detection of spontaneous combustion in coal mines.

Jan 1, 1980

By R. J. Davidson

The mechanism of gold adsorption on activated charcoal by R. J. DAVIDSON: M.Se., Ph.D. (Rhodes) (Visitor) The adsorption of gold onto activated charcoal is most dependent on the concentration and character of the 'spectator' cations present in the adsorption medium. In the presence of calcium ions, gold is adsorbed as the calcium aurocyanide complex. The degree to which the aurocyanide complexes are adsorbed follows the series Ca> Mt:> H> Li> Na> K, calcium aurocyanide being the most stable complex and potassium aurocyanide the least firmly bound. If a loaded charcoal, where the gold is present as the calcium complex, is treated initially with either sodium carbonate or potassium carbonate solutions, the gold can subsequently be eluted from the charcoal with hot deionized water as either the sodium or the potassium complex respectively. The elution of gold with deionized water appears to be most attractive practically and economically, and has several potential applications in the recovery of gold from dilute solutions.

Jan 10, 1974

By Sigmund J. Sulinski

The following is a progress report on a continuing study being made by the Sanitary District for purposes of developing reliable data for predicting costs and progress on future tunnel contracts. All data available to date on five separate tunnel contracts has been analyzed. All were machine-mined in soft ground, all used steel ribs and wood lagging and finished inside diameters varying from 5'6" to 6'6". Basic data regarding progress per shift, hours mined per shift, hours of downtime per shift, cause of downtime and type of soil mined were reported by the District's resident engineer at the job site. Figure 1, Weekly Mining Report is an example of the form used. Data regarding manpower and equipment used during tunnelling operations was also supplied by the resident engineer during the course of construction. Soil type being mined was verified by the resident engineer during construction, by visual observation, and compared with data listed on a previously prepared soil profile. The soil profile is a graphic presentation of anticipated soil stratas superimposed on a cross section

Jan 1, 1997

The optimization of sample spacing In South African gold mines by J. M. RENDU*, Eng. Se.D., M.S. (Min.) U.S.A. (Graduate Member) A first attempt is made at optimization of sample spacing in South African gold mines. The De Wijs model, which is shown to give a good representation of the geostatistical properties of gold values, is used to analyse the influence of the distance between samples along a stope face on the error of estimation of the stope value. The influence of other factors such as the face advance before resampling, the sample density, and the stope size, is also considered. Practical conclusions are drawn concerning the optimum sampling policy to be followed in various situations, and it is shown that sampling on a regular grid does not necessarily give the best results.

Jan 4, 1976