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Jan 1, 1943

By P. Khattri

At Tata Steel, Coal is washed in gravity and froth flotation circuit at 13-15 mm size and below. Being coal is high in ash (~35%) and difficult washability characteristics (having high (~40 %) NGM at desired ash levels) needs more and timely quality data of ROM for effective optimization and process control. Conventional approach of supplying quality data takes 4-5 hours time. This means during this period, it is assumed that coal is having similar characteristics as of previous set and it is not possible to fine tune during this time which resulted in yield loss. Hence producing clean coal on agreed ash value consistently is a challenging task because of high NGM and variation in input quality. To overcome the problem of collection of representative sample and timely result a new technology was adopted Prompt Gamma Neutron Activation Analysis (PGNAA) technology which is basically an online analyser using Gamma rays as the source to measure the ash content in coal running on a conveyor which gives real time ash analysis. The details of this technological intervention are discussed in details in this paper. Keywords: near gravity material, PGNAA

Sep 1, 2012

By Edward J. Way

+1KLEINFONTEIN GROUP CENTRAL ADMlNISTRATION, BENONI, TRANSVAAL, S. AFRICA. The cost and the speed of sinking a shaft are factors of so great importance in operating a mine, that the data given in Table I., herewith published, will be of interest and value to all engaged in practical mining; and for this reason the data are communicated for permanent and accessible record in our Transactions. The figures 'of cost cover the period from January 1, 1903, to May 31, 1903, during which time the total depth sunk was 858 ft. So far as I know, the cost of sinking per foot (£13,15s., 11.04d.) of a shaft of the dimensions 21 ft. by 6 ft. in hard rock, is the cheapest yet on record; and the speed of 213.5 ft. per month, which was attained during May, 1903, is also the best record for speed in sinking in rock so hard as that of this shaft. During the period from January 1 to May 31, 1903, there were 144 rounds worked, involving 4,032 holes, of a total depth of 28,963 ft. 2.4 in., which is equivalent to an average depth of 7 ft. 2.2 in. per hole bored. These data are of added interest from the fact that the work was done practically by native labor.

Jan 1, 1905

The paper will cover the basic reasons for alkaline leaching, a brief description of the circuit and the reasons for the flowsheet used. Changes made to the flowsheet, including the use of mechanical agitation of pachuca slurry, the use of oxygen and its effect on extraction, the use of lime and its effect on process economy, and the environment, will be described. A brief description of a unique semi-autogenous mill and future circuit changes will be included.

Jan 1, 1979

Commodities statistics and otter information are available through the following t et systems: Internet Access: To acccess the USBM Gopher server on Internet, connect to: gopher.usbm.gov port 70, using gopher client software. Or contact the Systems Administrator for technical questions: Matt Klevemann, 412-892-6499 (klevemmc@miner.usbm.gov) These USBM materials are available on Internet, with more to come in the future: Publications and other research findings, including this bimonthly publications list, newsletters, tech transfer updates, enviromental technology research, health and safety information. USBM software products Media materials and speeches. Mines Data: Computer bulletin board. Log on via modem through 202/501-0373, or call 202/501-0406 for technical assistance. Mines FaxBack: Return fax service. 1. Use the touch-tone handset attached to your fax machine's telephone jack. (ISDN [digital] telephones cannot be used with fax machines.) 2. Dial 202/219-3644. 3. Listen to the menu options and punch in the number of your selection, using the touch-tone telephone. 4. After completing your selection, press the start button on your fax machine.

Jan 1, 1995

By J. J. Bean

This paper, describing the milling practice at the oxide concentrator of the International Smelting Co., is one of a series on milling methods and costs being published by the United States Bureau of Mines. GENERAL DESCRIPTION The oxide concentrator is properly an integral part of the Tooele plant of the. International melting Co., located 5 miles from Tooele, Tooele County, Utah. It has a capacity of 300 tons of ore per day and uses an all-flotation process to treat custom siliceous oxidized lead ores obtained principally from the Tintic district in Utah. Ores found amenable to the process are purchased on a custom basis, the principal tonnages being obtained from the Tintic Standard and North Lily mines.

Jan 1, 1933

By Henry S. McDevitt

External Shock Mitigation (ESM) is being studied as a possible means of retrofitting existing buried structures to provide additional protection from ground shock. As part of this study, two tests were conducted on four ESM models and a control structure. The test articles were placed at a carrnon distance and subjected to the ground motions created by a buried explosive charge consisting of 2,ODO pounds of nitranethane (NM). Adequate instrumentation data were obtained to assess the response of the four ESM models. The assessment relied heavily on direct comparison of horizontal motions measured in the models, with similar measurements in the control structure. From the tests, it was observed that peak accelerations were reduced by a factor of 5 by the ESM. However, the particle velocities and displacements were not significantly affected by theEIS.

Jan 1, 1997

Theories of ore genesis. have both practical and philosophical application-practical in that they influence our search for new ore bodies; philosophical in that they provide a test for our theories of petrogenesis-and our ingenuity.For example, the theory of granitization requires an explanation of ore genesis compatible with the general concepts of granitization.Our understanding of some processes of ore formation, such as supergene enrichment, or the formation of residual lateritic iron ores, is so complete as to permit of nq controversy.For other ores, like the oolitic iron ores of England and France, and elsewhere, or the segregations of chromite or ilmenite in basic igneous rocks, the broad principles are generally agreed on; dispute is limited to details of process.But for a wide range of ore deposits there is no such agreement. Completely incompatible hypotheses are advanced to explain' identical facts, and we have difficulty in finding new facts or criteria that will distinguish unambiguously between them.In thinking about such ores, a co:n;venient starting point is provided by Schneiderhohn's (1953) fourfold division of ore deposits:1. The secondary hydrothermal ore deposits occurring in Mesozoic-Neozoic cover strata of Europe.2. The "regenerated" younger ore deposits in Alpine type mountain chains.3. Post-Cambrian primary hydrothermal ore deposits.4. Ore deposits of the PreCambrian shields.To these we may add a fifth group:5. Stratigraphically controlled sulphide deposits.

Jan 1, 1956

By Scales PJ

Fatigue is the primary cause of failure of structural and mechanical components subject to dynamic loading. Recognition of this basic fact and the development of appropriate techniques and details are important in the design and repair of off highway trucks (OHTs). The frames and appendages of OHTs and other mobile plant used in the Pilbara are subject to tough operating conditions. Any fatigue-prone details quickly show up and become a maintenance liability of considerable concern. Much of this equipment is approaching the limit of its fatigue life and maintenance managers face decisions on whether to repair or replace. Even new equipment often contains some poor details which suffer distress soon after commissioning. In those cases a repair is required which will reinstate the detail to its original intended design life. Repair details must be practical and cost effective. They must also be tailored to the capability and expertise available in the field or in local manufacturers' establishments. This is particularly important where original equipment was manufactured overseas and long delivery times are involved. Lessons are drawn from components which have failed, using the evidence constructively, to provide an upgraded part or an improved substitute. With the experience now available it is relatively easy to extrapolate to cover new problem areas. This paper describes specialised techniques of mechanical fastening and detailing for low fatigue susceptibility, built up over many years of experience with OHTs and other mining plant and equipment in the Pilbara.

Jan 1, 1982

By Ivette E. Torres

The series summarizing the prices of the major nonferrous metals on the stock exchanges of the United States and the United Kingdom (London Metal Exchange) has been continued this year in tables 22 and 23. Time constraints have prohibited preparation of other price information that has appeared in this study in previous years. Users are urged to consult the 1993 U. S. Bureau of Mines publication Metal Prices in the United States through 1992, which gives an analysis of historical price series and trends, or the 1993 edition of Mineral Commodity Summaries for current U.S. prices on non fuel commodities, and to utilize U.S. Department of Energy sources for information on fuel material costs.

Jan 1, 1994

By E. J. Ripling, S. I. Liu

IT has been shown in a number of recent publications that much information on the mechanical behavior of metals can be gleaned by first deforming test specimens under one set of conditions, and then evaluating the effect of this deformation by means of a subsequent tensile test. A straining procedure of this type has been applied to study the flow behaviors of a number of metals.1, 2 In these studies the prestraining and testing were both tensile strains, while the straining temperature was varied between the prestraining and testing steps. These data indicate that there is a more or less general flow behavior exhibited by all metals which are pre-stretched at one temperature and then tested in tension at a second temperature. Prestraining a metal at a high temperature produces a lower yield strength during the subsequent low temperature strain than would the same total strain at the lower temperature. On reversing the order of the strains, low temperature prestraining produces a higher yield strength during the subsequent high temperature straining than would a single high temperature strain of the same magnitude. Unlike the flow behaviors, the fracturing characteristics of metals when prestrained under one set of conditions and tested under a second set of conditions is quite material dependent. The fracture behavior of a number of steels2" as well as of a commercially pure zinc,4 have been investigated by these two-step tests and was found to depend upon the position of the transition temperature with respect to the prestraining and testing conditions. Since these fracturing phenomena are complicated by the appearance of the transition temperature, it has been difficult to reliably define the basic effect of a two-step straining procedure in fracturing. Metals crystallizing in the face-centered cubic system do not exhibit transition temperature effects so that the mechanical characteristics obtained on these materials could serve as a base for two-step straining behaviors. Consequently groups of specimens of the aluminum alloy 24s-T4 were prestrained various amounts at room temperature in either tension or compression after which these strained specimens were further strained to failure, or tested in tension, at either room or some lower temperature. Other groups of 24S-T4 specimens were prestretched at various low temperatures after which these were tested in tension at room temperature. These straining techniques then made it possible to compare the behaviors of aluminum with the behaviors previously presented for steels. Material and Procedure The commercial aluminum alloy 24S-T4 in the form of 3/4 in. rods was used in this investigation. The material was subjected to the following treatments before machining: 1—resolution treating at 920" & 10°F for 45 min, 2—quenching in water at room temperature, and 3—aging at room temperature for four days. The re-heat treated material was then machined to either of the specimen shapes shown in Fig. 1. Fig. la shows the threaded-end specimen used for prestraining in compression. Fig. 1b shows the specimen used for both prestrain in tension and final testing. The material subjected to precompression in the form of the specimen shown in Fig. la was re-machined to the specimen shape in Fig. 1b for final testing. Prestraining in tension and final testing were done without any intermediate machining. All straining was performed on a 10,000 1b Riehle tensile testing machine. Tensile strains were conducted in a specially designed concentric fixture which produced an eccentricity of less than 0.001 in." The change in diameter at the minimum section of

Jan 1, 1954

By D. R. Gibbons

This morning I would like to speak to you about an area of chemistry that is enjoying a revival-organometallic compounds. This renewed interest, principally stimulated by defense needs, has already created new markets for the products of the mineral industry. Although the consumption of metals in these new products is modest at oresent, several hold promise of importance. Because this is a new and growing market, I am sure the Council of Economics is aware of many of its facets and is interested in new developments. Of course, the chemical industry has been a significant consumer of minerals for many years. I estimate that in 1957 the chemical-industry purchased a total of $1175 million worth of minerals as raw materials (not including fuels). This estimate can be broken down as follows: [Metals and metallic minerals $375 million Nonmetallic minerals (excluding hydrocarbons ) 330 million Hydrocarbons 470 million $1175 million]

Jan 1, 1958

By Paul W. Zimmer, Carl E. Dutton

Iron ore in the Menominee district is mined from two iron-formations of middle Precambrian age. The older formation is present in the northeastern part; is composed mainly of hematite, magnetite, quartz, and minor silicates; and contains about 34 per cent iron. The rock has been so coarsened by meta- morphism that concentration of magnetite and hematite is feasib!e, and pellets containing more than 60 per cent iron are being produced. The older formation is also present in the southeastern part where it has 1:een only slightly metamorphosed. Ore containing more than 50 per cent iron was formerly mined from local residual concentrations of iron oxides from which silica had been sufficiently leached, or replaced by iron oxide, or affected by combinations of these processes. The younger iron-formation occurs in the western part of the district and, if unaltered, is interlayered siderite and chert. The ore in this area also contains more than 50 per cent iron and formed as local residual concentrations but in two stages. The siderite was converted to iron oxides (hematite and "limonite"), and silica was contemporaneously or subsequently removed by leaching, or replacement, or combinations of these processes.

Jan 1, 1968

By Carroll Wegemann

THAT Colorado was producing oil and gas before the fields of the Mid-Continent were discovered is a fact too frequently overlooked. As early as 1862, oil was obtained in the Florence district (see Fig. 1) from seepages and shallow holes. The first well that could be regarded Fig. 1. as being truly commercial was drilled in this field in 1876. The field is now producing 100,000 bbl. per year, and is credited with a total production of approximately 11,000,000 bbl. The small field near Boulder, Boulder County, was opened in 1901; production has now practically ceased but the field is credited" with a total production of 610,000 bbl. Oil was discovered at Rangeley in 1901, and the field supports a small local refinery at the present time. The first shallow well in the White River gas field was drilled in 1892, and the wells now producing have been

Jan 3, 1925

By Albert Sauveur

Some writers believe that when austenite transforms completely into pearlite on slow cooling through the thermal critical range, such transformation does not imply the formation of any of the so-called transition constituents: martensite, troostite and sorbite. Might it not be claimed with as much justification that when water freezes it does so suddenly, solid ice being obtained without passing through the intermediate stages of ice and water? Obviously, regardless of the speed of solidification, this would be erroneous. Before reaching the completed solid condition, this must of necessity pass through an unbroken series of stages when the system consists of mixtures of water and of ice, the former decreasing and the latter increasing in amount. Are not these "transitionV stages in the freezing of water similar to the transition stages occurring in the transformation of austenite into pearlite? To clarify, let us consider in Fig. 1 the mechanism of the transformation of eutectoid steel from its austenitic to its pearlitic condition as it cools slowly through its thermal critical range. It is generally admitted that this transformation is the result of two distinct phenomena: (1) the allotropic change of gamma iron into alpha iron and (2) the crystallizing out of solution of the carbide Fe3C. Whether this crystallizing of Fe3C implies also its formation is immaterial for our purpose. In other words, whether it is the carbon in atomic dispersion which is present in gamma iron or molecules of Fe3C has no bearing upon the matter to be discussed. The transformation of gamma iron into alpha iron cannot take place suddenly. It must of necessity be progressive, regardless of the speed with which it may take place. At A, for instance, there would be present AB gamma iron and BC alpha iron. The distance MN does not refer to falling temperature, but to the passage of time. It may be assumed that the transformation takes place at a constant temperature (the Ar321 point). In a similar way, the crystallization of Fe3C out of the austenite solid solution must be progressive as depicted between M and N. At A there would be present AB gamma iron, BC alpha iron, CD carbon dissolved in gamma and in alpha iron and DE Fe3C. This condition may be described according to individual preference as martensite or troostite. To sum up, can the metal pass from condition

Jan 1, 1931

By Howard M. Graff

The Inland Steel Company operates five underground iron mines in the Lake Superior District. The two largest of these, from the standpoint of productive capacity, are the Sherwood Mine in Iron River and the Bristol Mine in Crystal Falls, both on the Menominee Range of Michigan. It is at these two mines that we have had our principal experience with belt conveyor installations underground, .At the Sherwood Mine, which has an annual capacity of about 450,000 tons, the first conveyor belt installationwas made in 1947 when conveyors were installed in the main haulage drifts on the 1200 ft, level, It was estimated at that time that approximately 5,000,000 tons would be mined from the stopes above the 1200 ft, level and. that if all this material could be moved to the shaft by belt conveyor, the entire cost of operation, including maintenance and the amortization of the equipment, would be about $,05 per ton, which was slightly more than half of what the cost would have been by conventional tramming methods employing locomotives and cars. Now, ten years later, the 1200 ft, level is almost completely mined out and we have actually removed. 5,200,000 tons and. the average cost of transporting this material to the shaft by belt conveyor has been $.095 per ton. Since there has been a substantial increase in hourly rate of pay and also in the cost of materials since 1947, we feel that the anticipated savings were very nearly realized., The 1200 ft, level installation at the Sherwood consisted of two 36" trunk line conveyors 815 feet long and 380 feet long, respectively, deliverying ore to the shaft. These in turn were fed. by three lateral 36" conveyors which paralleled the sides of the orebody, These gathering conveyors passed under draw points to which ore was brought from the stopes by mea S of scrapers or shaker conveyors, Shaker conveyors were used for a number of years in conjunction with the conveyor belt system of haulage but it was finally concluded that with this particular type of ore, the maintenance on shaker conveyors was excessive. Therefore, more recently, we have gone back to scrapers for the shorter distances and. are using belt conveyors in the scraper drifts for the longer distances. After this belt system had been in operation for about three years, it had proved to be so successful that it was decided to proceed with the same system or. a new level to be opened up 200 feet below. Instead of sinking the shaft and driving a horizontal drift to the orebody on the 1400 ft, level, an inclined conveyor drift was started near the shaft at the 1200 ft. level and driven downwards toward, the orebody at a slope of 15 degrees. The conveyor installed in this inclined drift is 36" wide, 990 feet long, is powered. by a 100 hp motor, and is capable of delivering 300 tons per hour to the 1200 ft, level shaft pocket. It is fed by lateral horizontal conveyors on the 1300 ft? 1400 ft., and 1425 ft, sub levels. Wien the inclined drift was started, the rock was scraped from the breast directly to the rock pocket at the shaft. As the distance increased., double scraping was employed, until the advance had reached 350 feet, At this point a portion of the final conveyor was installed, with a scraper slide near the breast, T e drift was then advanced be scraping on to the conveyor until a sufficient distance had been driven to permit the installation of an additional 200 feet of conveyor. This proved to be a very efficient and economical means of moving the development rock to the shaft and obviated the need of using cars or an inclined skip way, At the present time 85 percet of tie entire mine output is being mined below the 1200 ft, level and is delivered to the shaft via the inclined conveyor. The system appears to be working as well and as economically as did the conveyor systemonthe 1200 ft, level.

Jan 1, 1958

By D. J. Houlahan

ABSTRACT Sorting has the potential to massively improve the pro?tability of mining base metal, hard-rock ores. However, several barriers to the increased application of sorting have been identi?ed, including a lack of mineral-speci?c sensors available to the industry. This paper presents the outcomes of acollaborative project to develop an induction-balance sensor speci?cally for low-grade copper and nickelores. A review of the basic principles of induction-balance sensing and of the sensor-rock interaction is presented. Early development and testing of the sensor on ores from the Thompson nickel belt in northern Manitoba is discussed. Shortcomings of the prototype identi?ed in early testing have now been over-come, leading to improvements in design and construction, as well as sensor accuracy. The improve dsensor has now been tested on additional ores from the Sudbury Basin, with good results. A discussion of potential applications is presented and recommendations for future development are made.

Jan 1, 2010

NEW YORK SECTION Executive Committee DAVID H. BROWN, Chairman JOHN H. JANEWAY, Vice-Chairman F E. PIERCE, Secretary, 35 Nassau St., New. York, N. Y. P. A. MOSMAN, Treasurer LEWIS W. FRANCIS BENJAMIN B. LAWRENCE At the meeting of the New York Section held at the Machinery Club on Dec. 8. 1915, the subject was "The Engineer in Modern Warfare, with Especial Reference to the Present European Conflict." Dr. Henry S. Drinker, who is Chairman of the Institute committee on the Engineer's Reserve Corps movement, opened the evenings' talk with a short statement of the aims and advantages of the Students' summer military camps, fostered by the Society of the National Reserve Corps, he being a member of the Advisory Committee of University Presidents. The speakers of the evening were Col. William M. Black and Col. John Biddle, both of the Corps of Engineers, U. S. Army. Col. Black is the

Jan 1, 1916

By Bradford F. Townsend, Gary Peach, Roger Rothenburger

From the experience of the authors on recent large infrastructure Design-Build projects this paper reviews major lessons for Contractors and Owners in the delivery of large Design-Build infrastructure projects and some major pitfalls and warnings to both Owners and Contractors. The paper is written from both the Design and Construction perspective. A case history is presented that details the approach employed to ensure a quality project consistent from the initial design phase through construction and outlines the strategy used to guide the Design-Build process to an acceptable completion. Suggestions are made for Contractors and Owners for handling the Design and the Construction elements of Design-Build contracts.

Jan 1, 2003

By Gordon DM

Tyres account for 25-30 per cent of the operating costs of large capacity haul units as used in open-cut mines.Tyre operating costs can be substantially reduced and often contained in real terms by applying knowledge that is now available.This paper describes certain specific advances in tyre management, namely batching, bias adjustment, cumulative plotting and the so-called "pressure-temperature" system of tyre pressure control, originated on the Mt Newman Mining Company's Newman minesite, and discusses the contribution that each has made to improving tyre management and reducing costs.

Jan 1, 1983