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By George J. Young

The nature of slimes handled in the treatment of gold- and silver-ores has been discussed in technical literature to a considerable extent. The subject of slime-filtration from the practical worker's stand-point has also received much comment, arid scattered through the literature of the subject are descriptions of many slime-filtration installations. Articles of this nature serve a valuable purpose and assist materially in the design of new and the improvement of old plants. The subject of the physics of slime-filtration has been touched upon to only a slight extent. The underlying principles are worthy of niore intensive study and experimeritation than they have received, and the main purpose of this paper is to present the results of such study and experimental work as will serve to make clear in part at least many of the principles which control the filtration of slime. Nature of Slime. Much has been written concerning an accurate definition of the term "slime," but no comprehensive definition seems to be gcnerally accepted. The reason for this is clear. A slime consists of at least three different substances, each, when separated, possessing distinctly different physical and to a certain extent chemical properties. These substances are extremely fine sand, a colloidal material which may bc and generally is in a coagulated condition, and a colloidal material which is in a non-coagulated condition. Suspending a slime in a relatively large volume of water by shaking and allowing sedimentation to take place, results in the fine sand settling out with comparative rapidity, followed by the coagulated material, which settles niuch more slowly and finally a certain portion remains

Jan 1, 1912

By C. Gregory Knight

Adequate planning for the development, operation, and reclamation of a surface mine requires attention to present and future uses of land, both on the mine site and in the mine vicinity. This paper outlines land use implications of surface mining, and suggests procedures that could link mine planning, mine operation, and reclamation to more general land use concerns. Mining is viewed as a temporary use of land that may irretrievably commit land resources away from some future activities, but may allow other uses, some of which may have been impossible without mining. The paper accepts the premise that surface mining should attempt to minimize environ-mental damage and to maximize future alternative uses of land by appropriate reclamation. I. The Effect of Surface 1'1ining on Land Use Surface mining is a temporary utilization of the land most often criticized because the disturbances it creates are of far greater duration than the actual extractive operation, Resource recovery disrupts existing activity on the land, at least temporarily, and

Jan 1, 1977

By W. M. Bangert, F. S. Boericke

"INTRODUCTION Determination of the thermodynamic properties of metallurgically important compounds of chromium has been one of the activities of the Pacific Experiment Station of the Bureau of Mines. Earlier reports have dealt with the entropies 4/ 5/ of chromium, chromic oxide, and chromous and chromic chlorides, with the thermodynamic properties of the chlorides of chromium, 6/ and wits the thermodynamic properties of the carbides and oxide of chromium. 7/ Evaluation of the thermodynamic properties of chromite, FeO.Cr2O3, is desirable, as this material in impure form constitutes the only natural source of chromium of any consequence.Two general methods are available for directly determining heats of formation - (1) measurement of heats of combustion and (2) measurement of heats of solution. Neither of these methods is directly applicable at present to ferrous chromite, which accounts for the lack of previous data. Combustion of a stoichiometrical mixture of iron and chromium under conditions prevailing in a calorimetric bomb yields a mixture of iron and chromium oxides rather than chromite. None of the usual calorimetric solution media dissolve chromite at temperatures low enough for solution calorimetry. Sulfuric acid and an oxidizing agent, such as MnO2 or CrO3, are known to dissolve chromite, but the possible calorimetric use of t is medium would require long preliminary investigation. Consequently, recourse must be taken to some indirect method. At the start of the present work, the most promising method appeared to be the determination of equilibria in the selective, reduction of the iron in chromite by hydrogen;"

Jun 1, 1945

By A. R. Elliott

In the early part of the your 1919 the Bureau of Mines undertook a study of methods of handling oil after it had buon produced, with the view of pointing out the losses due to evaporation and other causes. Observations on present methods show that the oil is subject to largo losses in both quantity and quality from the time it loaves tho well until it is recoivod by the pipe-lina company. During this time it is splashed into four or more tanks of various sizes and with little or no protection over the tops. From the settling tank, where the flow of oil is tamporarily stopped in order to permit sparation of ter and sediments, through the gago tanks and leaso gathering tanks to the largo tank storage where it is hold for many days, rich gasoline vapors roadily escape, especially from tho ghor gravity oil. As no effort is made to measure the oil before it reached the storage tanks, where it is delivered to the pipe-line company, the lossos of the light products of the oil can only be approximated, and, as final results will show, are no doubt usually very much underestimated. In conducting this investigation, the Bureau has endeavored to make tests that would show quantities and values lost, in order to impress better upon those concerned what might be saved through a little more diligence. Eperiments were conducted on both California and Mid-Continent oils. The field operimental work done in California, on which a report is to be published in the near future, is cutlined briefly below: The field work consisted in collecting from operating companies data on storage of oils in large tankage and in performing experiments in the field on storing and piping oil to small lease tanks under practical conditions. Acourate Easurements were takon on the volume, gravity and gasoline content of the oil as it passed through the various stages in its removal from the lease. The work extended over the four seasons of the year in order to obtain better the effect of varying winds and high and low atmospheric temperatures during those periods. Thanks are due to the many oil operators who have taken a personal interest in the work and gave valuable information and assistance. One company furnished the oil and tanks and much of the apparatus and labor. This company also per- mitted the work to be done on its properties in the Coalinga field. This was of material aid, as the results were to be comparative and therefore it was necessary that the same gravity oil be used throughout the experiments.

Oct 1, 1920

By Gislan William Guimarães

Neste trabalho avaliou-se o efeito de diferentes ciclos térmicos na microestrutura e propriedades mecânicas de um aço Dual Phase revestido por imersão a quente, da classe de resistência de 800 MPa, a partir de simulações em escala piloto no equipamento HDPS (Hot Dip Process Simulator), ensaios dilatométricos, tração à temperatura ambiente e flangeamento. Nas simulações de recozimento contínuo foram experimentadas duas temperaturas de encharque no recozimento intercrítico (740°C e 780°C) e três temperaturas de patamar isotérmico no resfriamento rápido (610°C, 560°C e 510°C). A caracterização microestrutural evidenciou que a temperatura de encharque de 740°C não foi suficiente para dissolução completa dos carbonetos formados na laminação a quente, resultando em frações reduzidas de segundo constituinte. Com isso, o limite de resistência mínimo de 800 MPa não foi alcançado. Além disso, os resultados de ductilidade e flangeamento se mostraram aquém dos obtidos nas simulações com encharque a 780°C. Nas simulações com temperatura de encharque a 780°C e isotérmicas de 510°C e 560°C no resfriamento rápido foi atendido o limite de resistência mínimo, com capacidade de expansão de furo ligeiramente superior à obtida nas simulações com encharque a 740°C.

Aug 16, 2017

By S. A. Swensrud

NINETEEN Thirty-Six was the biggest year in volume in the history of the oil industry, and unquestionably the best since 1929 in respect to profits. The quota of new and difficult problems to face seemed a little smaller during 1936 than in most recent years, and a somewhat better balance existed between the different branches of the industry. 'Domestic consumption of gasoline in 1936, estimated at about 475 million barrels-the highest on record, was approximately 11 per cent above 1935, and 26 per cent above 1929. Demand for crude oil increased in about the same proportion: over 1935, and the average production, of about three million barrels daily,' constituted a new high level.

Jan 1, 1937

By L. Don Leet

Abstract Earthborne vibrations from blasting and other sources, including rock bursts, can now be recorded effectively. The nature and magnitude of vibrations from various sources have been investigated and certain applications of the knowledge thus gained have been made. Vibrations from blasting have been measured on special equipment over a range from an electric blasting cap at a few feet, through the largest quarry shot in history to date ( 1,-362,985 lb.), to the first atomic bomb, in uew Mexico on July 16th, 1945. Laws relating amount of explosive to amount of vibration at different distances have been developed and tested. Special studies have been made of the effects of vibrations on buildings, particularly from the standpoint of possible structural damage. Recorded vibrations are used to study the effects of modern short-period delay shooting. It ?has been found that short-period delay firing is extremely effective in reducing vibrations under the right conditions, but with certain limitations. In quarry shooting, there appears to be a minimum number of holes below which vibrations are not appreciably reduced by short-period delay firing. In several instances this minimum has been near 7. Vibrations in the ground from rock bursts and the effects of mining in stresesd ground have been studied both underground and on the surface in a search for a rock burst warning system. Introduction Earthborne vibrations from blasting and other sources, including rock bursts, can now be recorded effectively. Analyses of blasting records have been yielding increasing funds of information of practical as well as theoretical interest. The nature and magnitude of the vibrations have been investigated with special reference to their effects on structures.

Jan 1, 1951

By J. A. Procarione

Introduction Ventilation engineers have always felt somewhat uneasy when, in the normal course of their work, they are forced to consider the flow in any mine entry as "wholly rough." Under such conditions in pipes, friction factor is no longer a function of Reynolds' number. This assumption serves to simplify the problem and overcome an evident lack of information concerning the variability of K-factors. During the summer of 1985, a unique opportunity to investigate the reaction of friction factor to changing flow rates presented itself. A Utah coal mine was temporarily directing a substantial airflow through a single entry. By regulating the quantity, it would be possible to obtain a wide range of Reynolds' numbers in an entry composed of two distinct coal thicknesses. This paper describes the conducted study. The theory covering basic fluid flows in pipes that led to the questioning of constant K-factor is presented first. Experimental procedures are then described, including the use of a view camera in determining entry area and perimeter. Finally, a discussion of the observed variations in friction factor versus Reynolds' number is given. Changes of 34% and 45% in K-factor were seen in this study for the two entry heights. The implications of ignoring the relationship in this case and a call for an expanded research effort are also presented. Theory Since a gas is a fluid, the general principles of fluid mechanics are equally applicable to airflow in a mine entry as they are to the flow of water in a pipe. The Darcy equation is, therefore, equally applicable to pressure drop calculations in both situations. This famous formula was originally derived for use in circular cross sections and may be modified for any other shape by the use of hydraulic radius (defined as the area divided by the "wetted" perimeter). The Darcy equation relates the physical parameters of the pipe (diameter, length, and resistance to flow) and fluid velocity to the energy needed to create the flow. A study by Nikuradse (1933) brought to light the suspected dependency of the friction factor term in the Darcy equation upon Reynolds' number. By performing a large number of laboratory experiments, he established some basic concepts upon which other researchers built. Chief among these contributors was Colebrook (1939). Using commercial-grade pipe, he established an empirical relationship between Darcy's friction factor and Reynolds' number that is still in use today. If Colebrook's system of equations is plotted on log-log paper (as was done by Moody, 1944), the curves have some very distinct features. Of importance to the subject at hand is the relative response of friction factor to Reynolds' number at a given relative roughness. Simply stated, a pipe can appear to be either smooth or rough, depending on the flow conditions. As the Reynolds' number increases, the friction factor decreases at a decreasing rate until it becomes nearly a constant value. At this point, the flow is said to be "wholly rough." It is upon this condition that many traditional ventilation solution methods depend. For calculating pressure drops in a mine entry, Atkinson's equation is much more popular than the Darcy equation. Both of these formulas describe the same phenomenon and so have similar forms and functions. The K-factor in the Atkinson equation is equivalent to the Darcy friction factor and can be related by simply changing units, equating the pressure drops, and canceling like terms. A generalized form of this relationship is presented below as equation 1. K = yf/28,800g = [q]f/28,800 (1) where K is Atkinson's friction factor in kg/m3 (lb - min2/ft4), Y is the specific volume in Nt/m3 (lb per cu ft), p is the fluid density in kg/m3 (slugs per cu ft), g is the acceleration due to gravity (9.8 m/s2 or 32.2 fpsz), and f is Darcy's friction factor, which is unitless. The objective behind Eq. 1 is to show the strong correlation between K and f. Since these two quantities differ only by a constant (q]/28,000), the assumed independence of K-factor and Reynolds' number is suspect in light of the known response of f. Unfortunately, the formulation does not provide information concerning the actual relationship, as entry geometry likely plays a major role in the response curve. Only an indirect indication that such a relationship might exist is provided. Previous work on this subject was performed by Thomas Falkie (1958). The study involved a laboratory model composed of sections of straight, steel duct and a range of Reynolds' numbers from 15,610 to 137,200. Results from this work show a variation in friction factor with Reynolds' number in much the same way as it was found to vary in pipes. Over the range of velocities examined, a decrease of approximately 38% in K-factor was observed. This previous experience provides additional incentives to investigate the phenomenon under field conditions. Past model studies done at the University of Utah by Ozukurt (1945), Biron (1944), and Greenhalgh (1942) present similar evidence of this variability. More recently, Kharkar's (1974) study of coal mine friction factors contains similar indications that K-factor is not constant in all situations. Taken together, the data

Jan 1, 1988

By A. Y. Lee

Prior work at the Bureau of Mines resulted in the successful development of a bench-scale, combination electrorefining-electrowinning method for recycling the lead from scrap batteries using waste fluosilicic acid (H2SiF6) as electrolyte. This paper describes larger scale experiments. Anodes cast from scrap battery lead were electrorefined in a 20-L multielectrode cell for 3 to 7 days. The anodes, containing 2 to 2.5 pct antimony, were ideal for obtaining firm and adherent slime blankets. Cathode deposits, assaying 99.99 pct Pb, were obtained, with current efficiencies near 99 pct. Sludge leaching was done in 100-L tanks followed by filtering in 61 cm square vacuum pan filtersu Lead of greater than 99.99-pct purity was recovered from the filtrate by electrowinning in a 20-L multielectrode cell using insoluble Pb02-Ti (lead dioxide-coated titanium) anodes and pure lead cathodes. The fluo-silicic acid electrolyte depleted in lead was repeatedly recycled to leach more sludge, and there was no problem with impurity buildup. The amount of Pb02 formed on the anodes during electrowinning was less than 1 pct of the total lead deposited on the cathodes, as long as the phosphorus concentration in the electrolyte was greater than 1.3 giL. Emissions of lead in air were less than 10 ~g/m3, well below the proposed OSHA limit of 50 ~g/m3.

Jan 1, 1984

By Shae K. Kim

The aim of this study is to manufacture magnesium alloys with alkaline earth metal oxides (BeO, CaO, MgO or SrO) additions with the objectives of (1) ensuring safety during processing and applications by raising the ignition temperature and reducing oxidation, (2) protecting the environment by reducing or eliminating use of protective gases, (3) maintaining or improving elevated temperature properties with lower amount of Ca or Sr or rare earth metals when compared with conventionally developed high-temperature magnesium alloys, (4) developing cleaner strip casting and continuous casting processes without hot tearing and (5) obtaining all of these objectives without sacrificing mechanical properties or increasing the cost of magnesium alloys.

Jan 1, 2006

By B. Hayen

The principal advantages of fibre optics as compared to copper wire are well known and include almost perfect electromagnetic isolation, light weight, small size, excellent transmission security and substantially better bandwidth/distance performance. The decreasing cost of the optical fibre technology (both fibre cable and equipment) has led to another generation of private networks, which provide much larger bandwidths, very high reliability and an increase of the maximum geographical coverage. The larger bandwidth allows to transport all types of information on a single network. Typical communication requirements are speech (audio), computer data, LAN info, control information, video, etc. OTN or ‘Open Transport Network’ is a transmission system based on the latest available technology in fibre optics. It is characterized by the dual ring approach, resulting in high network availability, and the integration of different types of services in one network. As such, it can fulfil almost all transmission requirements for voice, data, LAN, video and any special service required.

Sep 1, 2001

By F. R. Jones, B. W. Taylor, A. R. MacPherson, L. J. Lamb

"The Lake St. Joseph Iron Deposit is in Northwestern Ontario. Exploration to date by Steep Rock Iron Mines Limited has indicated an ore reserve of 683 million long tons. Metallurgical investigations have proved that suitable oxide pellets and/or superconcentrates can be economically produced from this ore. Studies of the Lake St. Joseph iron ore deposits have covered the period 1956-71, and have embodied applications of the improvement in mining and processing technology over this period. Market demand in the early 1960's for high-grade oxide pellets as a replacement for natural iron ores for the blast furnace first drew attention to the potential of the Lake St. Joseph deposit. The current market trend toward utilization of sponge iron to replace steel scrap as feed to electric furnaces and cupolas now suggests that the deposit can better be exploited as a prime source of superconcentrates."

Jan 1, 1972

By Leon H. Bruner

This paper presents a case study describing how a global consumer products company with 138,000 employees that markets over 300 brands in 180 countries is building sustainability into the rhythm of its business. This strategy extends beyond social investment programs by incorporating sustainability into the fabric of product design, manufacturing operations, employee engagement and stakeholder partnerships. During the implementation of this program it has been necessary to be explicit about sustainability and its importance to the business, to broadly define sustainability, to ensure that sustainability is not added work, to eliminate trade-offs between performance, value and sustainability and to implement programs to ensure that sustainability is incorporated into the DNA of the company. Our program continually emphasizes the importance of making no tradeoffs between consumer acceptance of sustainable products and sustainability investments. We also work diligently to overcome the challenges of engaging employees around the world to implement a single coherent sustainability strategy that delivers great results.

Jan 1, 2010

By Charles G. Maier

It has long been supposed that when crystalline materials are comminuted the energy used in the production of increasingly smaller grain sizes is not entirely dissipated as heat but that a certain portion is "stored" as a part of the internal energy of the material. This portion usually has been called the "surface energy" of the particles. The practical interest of the Bureau of Mines in this subject in connection with the energy requirements of crushing processes has led to the author's attempt to measure the "stored" energy in finely divided calcite by heat-of-solution methods1.t The experiments on calcite showed that "storage" of energy could not be proved for this material, because fine grinding caused a lack of chemical homogeneity evidenced by loss of carbon dioxide and subsequent adsorption of water on the surfaces of the calcite particles. When thermochemical correction was made for composition changes the corrected heat of solution was less for fine material than for coarse. Continuation of the experimental work into the problem of comparing work and heat in the deformation of metallic crystals, where the calorimetric difficulties were less, showed, however, that in the case of copper and aluminum a real discrepancy between work and heat could be shown. Similar results had previously been obtained by Farren and Taylor2 and Hort3 and more or less simultaneously with the author's work by Rosenhain and Stott4 and by Taylor and Quinney9 The results obtained by the different investigators were not satisfactorily consistent, but the experiments of Taylor and Quinney constitute by far the best figures obtained to date. The previous paper1 presented evidence to show that if energy is stored in the surfaces of crystals the densities of fine crystals should differ

Jan 1, 1936

By Robert J. Evans

Capital and operating costs were estimated using a wet suppression, fabric filter, and a combination system of the two for hypothetical hard rock stone crushing plants located in central Pennsylvania, operating at 300, 600, and 1,000 tons per hour. Fixed capital expenditure for the dust abatement systems ranged from $49,129 to $249,162. Annual operating costs for the dust abatement systems ranged from $8,394 to $46,606 (0.9 to 3.2 cents per ton). If these dust abatement systems are properly sized, installed, and maintained, efficiencies approaching 95 percent can be expected for reduction in weight of dust particles emitted before control.

Jan 1, 1975

By A. W. JR. Whitaker

Introduction Within the last quarter of a century the Lake St. John-Saguenay valley has been converted from a quiet agricultural district to one of the important industrial centres in the Dominion. First there was the expansion -of the pulp and paper industry, and then, starting a little over ten years, ago, the development, in large .blocks, of the enormous hydro-electric power resources of the Saguenay river. Coincident with this power development, the world aluminum industry was rapidly expanding and looking for a new source of cheap power. This was found in the Saguenay valley-and so, in 1925, Arvida was established by the Aluminum Company of Canada as a location for one of the largest aluminum plants in the world. Arvida, an incorporated city comprising an area of some ten square miles, is ideally located on a more or less level plateau about 350 feet above the Saguenay river. Seldom has industry stepped boldly forth and carved out of Nature a community with full city status. The process usually goes through the steps of camp, village, town, and city, involving improper planning or lack of planning; all of which has been avoided at Arvida by starting out in the right way. While this community has only a population of approximately 2,000 at the present time, it is carefully planned for a population many times this figure. Streets, city parks, business and residential sections, have been definitely planned, and, with a City government, proper ordinances were passed at the beginning to ensure the building and maintenance of a model industrial community. As the crow flies, Arvida is about 35 miles due east of lake St. John, and 0 miles west of the St. Lawrence river at Tadoussac. From a shipping standpoint, it is well served by the Canadian National railways, with direct lines to Quebec and Montreal, and by ocean shipping facilities at Port Alfred, which is about 15 miles to the east on the Saguenay river and is served by the Roberval & Saguenay railway. The latter has interchange connections with the Canadian National at Arivda, and also operates a branch line into the city of Chicoutimi.

Jan 1, 1933

By J. N. Brooke

"This paper deals with the training of the mining and mineral engineer and the role that these professional people must play in their company environment, particularly in relation to management.THERE IS SOME CONCERN in the mining industry that the numbers of engineering graduates attracted to it and the academic training that these people have received is inappropriate. Evidence for this is:1. -The meetings and studies initiated by the various mining engineering societies to discuss:(a) attracting students and graduates to the industry; and (b) the appropriateness of the present academic training for the needs of the industry."

Jan 1, 1968

By David Van Horsen

Operation and maintenance of California?s water tunnels is an important factor and vital link in California?s infrastructure. These tunnels are owned and operated by a variety of large and small private and public water and power utility companies, municipal agencies, and irrigation districts. Visionary pioneers such as Michael O?Shaughnessy (San Francisco Hetch Hetchy Water Supply System), William Mulholland (Los Angeles Department of Water and Power and Metropolitan Water District of Southern California?s Colorado River Aqueduct), and John Eastwood (Southern California Edison Big Creek Hydroelectric Project) built large and small water supply, irrigation and hydroelectric tunnels, which have supplied environmentally friendly-water supply, renewable electricity, and uninterrupted service to a burgeoning population and economy. This paper introduces these pioneers and describes several case histories and lessons learned during condition assessment and rehabilitation of tunnels providing enlightenment of California?s vital water projects.

Jan 1, 2008

By Barry James

Energy, like labour and materials, is one of the basic production inputs in the industrial minerals industry. This paper discusses the significance of the changing energy situation in Canada as it affects the industry. It is apparent that the importance of energy as a management concern has increased considerably since 1973. The importance placed on energy management today will undoubtedly be an important factor in determining company and industry sector strength and profitability tomorrow.

Jan 1, 1978

By J. W. Matousek

Cobalt behavior in pyrometallurgical processes is traditionally analyzed using slaglmatte distribution coefficients as functions of matte grades or matte iron contents. L(s/m) = (%Co) I [%Co] = f [%CuNi] or f [%Fe] The method is inconvenient to use in predictive mass balance work because of the interdependence of assays and mass quantities. An alternative procedure is proposed based on cobaltliron ratios for slags and mattes: Js = (%Co) / (%Fe), Jm = [%Co] / [%Fe], and J, = b + m [Jm]

Jan 1, 1993