Search Documents

By Chin J. Chang

Powder metallurgy (P/M) technique is known for its capability of producing near-net-shape parts. Its specific characteristics have resulted in low cost and eliminated of many secondary machining. However, more and more P/M parts do require additional operations to fulfil their complex geometric features and surface roughness. Many of the machining factors that influence the machinability of cast and wrought steel parts, such as cutting speed, feedrate, coolant, tool geometry and shape, are also considered in the machining of P/M components. The special feature in P/M structure is the porosity that can decrease the machinability and shorten the tool life. Different variables have been considered in the machinability of P/M materials. Densities and the free machining additive manganese sulphide (MnS), are the two main factors of material composition, which dominate the P/M machining performance. Machining process is the main method that generates the desired working surface of machining components. This paper will discuss the metallurgical structure of the powder metallurgy components, their physical properties and possible issues when encountering machining operation. Turning operation has been tested in this investigation to show the relationship between the cutting speed, federate, cutting forces and chip formation. This investigation also discusses how the free machining additive, manganese sulphide, affects the P/M structure and machinability in order to understand how the metallurgical structure can affect the machining operation and, how to obtain the optimised surface results.

May 1, 2001

By William J. Campbell

This Bureau of Mines report describes a study conducted to determine the relationship of mineral habit to particle size and shape characteristics for prismatic, acicular, fibrous, and asbestiform varieties of tremolite. Particle measurements were made with the petrographic microscope at X 1,250 and the scanning electron microscope at magnifications up to X 10,000. All of the varieties of tremolite, upon Wiley milling, produced a significant percentage of particles that meet the Federal regulatory criteria for counting as asbestos fibers. However, only the asbestiform variety gave milled particles that fell into a size range of >10 µm in length and <0.5 µm in width; some medical scientists consider this range significant for production of adverse health effects.

Jan 1, 1979

By R. A. Jankowski

Laboratory tests were conducted to evaluate the silica collection efficiency of flooded-bed scrubbers using six different filter panel designs at two operating velocities. Test results indicated that reductions in filter density negatively impacted respirable dust collection. Silica collection efficiency for the least-dense filter was as much as 33 % lower than the collection efficiency of the most-dense filter. At the low operating velocity, the least-dense filter allowed more than 40% of the respirable silica dust in the scrubber intake air to pass through the unit and back into the mine environment. Operation of the scrubber at the higher test air velocity increased silica collection efficiency regardless of the filter panel tested The density of the filter panels also impacted the quantity of air moved through the scrubber, with higher-density filters reducing scrubber airflow. For each filter, the relationship between dust-collection efficiency and air-moving capacity must be considered to determine the overall effectiveness for each mine application.

Jan 1, 2000

By Naohiro Kurokawa

Isa Limestone Quarry with an annual production capacity of 18 million metric tons is known as the largest limestone deposit in Japan located in the mountainous region about 20 mile northwest of Ube City, Yamaguchi Prefecture, Japan adjacent to Isa Cement Factory to which it belongs, and which constitutes a mainstay of Ube Industries? cement operating division. Isa Cement Factory is equipped with a N.S.P. kiln of capacity of 3 million metric tons per year, which is the largest of its type in the world. Geographically, it is situated in the south- western tip of the Mainland of Japan (Mid City, Yamaguchi Prefecture) and is bordered by the scenic Akiyoshi Karstic Plateau which is world famous for its huge stalactite grotto.

Jan 1, 1982

By Y Pan

The recycling of steel is a crucial aspect of the shift toward a sustainable metals industry. The emphasis on steel recycling through the introduction of the scrap based mini-mill concept is also matched with a desire for greater product quality and reduced environmental impact, which, in turn, has generated important innovations. There have been significant advances in the technology for recycling steel over the last 20 years and this paper will provide an overview of these developments and discuss future directions in steel recycling including scrap management, control of tramp elements, electric arc furnace technology and ladle metallurgy.

Jan 1, 2004

By Wilfrid R. Foster

The industrial importance of the sillimanite group of minerals depends upon the beneficial properties exhibited by porcelains and refractories in which substantial amounts of these minerals are utilized as raw materials. The presence of "sillimanite" (now known to be the closely related mineral, mullite) in conventional porcelains and refractories has been known since before the turn of the century. As early as 1906 German investigators observed a direct correlation between the "sillimanite" content of a porcelain and its electrical and mechanical properties. Acting upon this discovery, U. S. Bureau of Standards investigators during World War I developed improved pyrometer tubes and spark plug porcelains, by increasing substantially the amount of "sillimanite" at the expense of quartz. The success of these experiments, first reported in 1918, at once aroused a lively interest in the location of natural sources of sillimanite and its related minerals. As a result of diligent search, the large andalusite deposits in California were discovered in 1919. Within the next several years large deposits of kyanite and sillimanite in India and kyanite in the United States had been reported. The search for these minerals in quantity, by both private and governmental agencies, has continued unabated during the ensuing forty years. A number of domestic deposits of kyanite have been worked during the past 30 years. Of these, only the Virginian and South Carolinian deposits are currently in substantial production. The only commercial andalusite production in the United States has been in California and Nevada. A dumortierite deposit in Nevada, known since 1917 but ignored for want of a commercial use, began production in 1925. A topaz occurrence in South Carolina has yielded a small production since about 1940. Domestic production of andalusite, dumortierite and topaz had virtually ceased by 1950. There has never been any commercial development of domestic sillimanite deposits. Kyanite has been mined almost continuously in India since about 1922. The remoteness of the large deposits of Indian sillimanite had caused it to be neglected until 1949. In that year sillimanite production began, and it has continued to the present. South African andalusite has been marketed from the 1930&apos;s until the present time. From 1944 to 1955 Kenya, British East Africa, was an important producer of kyanite. Commercial deposits of kyanite in Ontario, Canada should soon be in production. The first production of kyanite in Europe began in Austria in 1953. No commercial deposits of mullite are known anywhere in the world. It is of interest to note that synthetic mullite, which as "sillimanite" first elicited interest in the A12O3-rich aluminosilicate refractories, has enjoyed a marked increase in production in recent years. This is a result of the gradual depletion of known deposits of high-quality kyanite and related minerals."&apos; Composition The sillimanite group includes kyanite, andalusite, and sillimanite, all having the same chemical composition (A12O3•SiO2) but different physical properties. Two other minerals, dumortierite and topaz, are also included in

Jan 1, 1960

By R. V. Wheeler, W. Francis

Of the methods that have been used for studying the chemical composition of coal, attack by reagents has not, in general, yielded much information. Most of the reagents used have been strong oxidants such as nitric acid or Schulze&apos;s solution. The use of a milder oxidizing agent, such as air at low temperatures, enables progressive changes in the character af the coal substance to be studied and thus helps toward an understanding of its constitution. British bituminous coals frequently have a banded structure. These bands (of four types) can be separated one from another and have been found to possess markedly different chemical characteristics, even when taken from contiguous portions of the same lump coal. It has been found convenient to give each of the ingredients of banded coal a distinctive name, more or less descriptive of its appearance, and the study of the chemistry of bituminous "coal" in England has resolved itself into a study of each ingredient separately. The coal chosen for this work was taken from the Top Hard seam at East Kirkby colliery, Nottinghamshire, a detailed chemical analysis of which has been recorded by Baranov and Francis.&apos; The banded structure was well marked and the bands could readily be separated. The research was confined to the brilliant vitreous bands (vitrain), the dull hard bands (durain) and the "sooty partings" main); for previous work had shown that the fourth type, to which the name clarain has been given, is intermediate in character, chemically, between vitrain and durain. The method of experiment was, briefly, to draw a slow current of moist air through weighed samples (50 gm.) of the three ingredients, vitrain, durain, and fusain, in the form of powder (through a 60-mesh and on a 90-mesh sieve) contained in glass tubes which could be maintained at a constant temperature during prolonged periods. After passing through the coal, the air bubbled into a measured volume of

Jan 1, 1925

With the iron ore industry in Australia producing hundreds of millions of tonnes of ore per annum, the associated costs of these operations extend into the billions. It is no surprise in the current economic climate that more and more companies are looking into different ways of optimizing their costs to keep their sites operational. One way of improving operations is the use of electronic initiating systems like i-kon and Uni tronic detonators. These systems have been used around the world to improve current practices and optimize drill and blast costs. However, these systems have yet to make an impact upon the iron ore sector in Australia. Some of the potential improvements include:pattern expansion and a subsequent reduction in drilling and explosive costs;improved fragmentation and hence increased dig rates, thereby driving $/tonne down;embracing the &apos;mine-to-mill&apos; concept by reducing the downstream costs of crushing and milling;improving the overall condition of pit walls and floors, leading to a safer working environment in which optimal haulage performance can be achieved; and improvements in vibration management around heritage sites and critical infrastructure, thereby saving the cost of relocation works. This paper introduces some of these concepts and the process of making the changes leading to potential savings from the improvements, using various examples as proof of the concepts.

Jan 1, 2009

By Tom Leistner, Urs A. Peuker, Martin Rudolph

"It is well known, that for conventional froth flotation techniques the processing of ultrafine mineral particles is generally inefficient and results in rather low-grade concentrates and relatively high losses of valuable minerals. Therefore, the investigation of other possible methods, which can selectively separate such fine particle systems effectively, is of considerable interest. In this study, the application of two-liquid flotation, a flotation-related process using oil droplets instead of air bubbles, is investigated as a possible processing strategy for the separation of ultrafine particle systems. The investigation involves the testing of the two-liquid flotation technique as simple laboratory-scale batch trials and moreover, the up-scaling to a semi-continuous process by using a modified lab scale flotation column. Magnetite and quartz particles, with particle sizes below 10 µm respectively, as academic mineral mixture and iso-octane and water as the two immiscible liquid phases are chosen for the experiments. To manipulate the wettability of the magnetite particles as well as the interfacial tension of the oil/water interfaces, surface active reagents of fatty acid basis are introduced in the system. The selectivity of the process is characterized by determining the removal of magnetite particles from the aqueous suspension through selective accumulation at the oil/water interface or extraction into the oil phase, respectively. Operational parameters including pH of the aqueous suspension, additional electrolyte addition and surfactant type as well as dosage are varied in order to maximize the efficiency and stability of the process."

Jan 1, 2014

Confirmation of significant mineable reserves of high grade silver ore at Elura Mine has led to the development of a high cost, high recovery mining system. At the contact of oxidised and sulphide ores lies a supergene zone of enrichment which has provided a contrast, not formerly imagined, to Elura&apos;s primary development and stoping operations. Because of the soft nature of the ore, intense ground support practice has been combined with a panel cut and fill continuous mining system to extract a reserve of small, but most valuable Proportions.

Jan 1, 1988

By A. W. Schlechten, R. P. Abendroth

Equilibrium H2S/4 ratios were determined as functions of temperatunz and composition in a hydrogen recirculation apparatus. A high-temperature solid solution exists in the range two-phase regionfrom TiS 1.96, to TiS1.30, Various thermodynamic quantities were calculated from the data. COMPOUNDS in the titanium -sulfur system have not receiyed much attention in the past, probably because they do not occur naturally in the earth&apos;s crust. However, titanium-sulfur compounds have been used in various metallurgical processes. The U.S. Bureau of klines&apos; studied the formation of ti- tanium-sulfide mattes from charges composed of rutile, pyrite, and carbon, with the resulting sulfide matte being chlorinated to form titanium tetrachlo-ride. Fishel, Roe, and Ellis&apos; investigated the de-sulfurizing action of titanium in steels, and Schwarz and Koster studied the preparation of metallic titanium from the sulfide using aluminum and magnesium reduction. The thermodynamic properties of some of the compounds present in the titanium-sulfur system may prove to be of some use in the consideration of future processes using these sulfides, and would

Jan 1, 1960

By Daniel Gendron, Luc Morin

"Concentrate sampling is a growing concern in the world's mining and smelting industry. The main modes of transportation for concentrate to the smelter are by truck or rail car in a bulk form, thereby limiting access to sample extraction equipment. In many cases, concentrate is shipped to a smelter by several suppliers therefore requiring individual manipulation of different customer samples in a safe and reliable manner. The Heath & Sherwood Bulk Product Sampler offers this feature as well as an economical and effortless way of obtaining samples in rail cars or truck boxes.In 1994, Noranda Metallurgie in Rouyn-Noranda, Québec purchased a self contained Bulk Product Sampler to extract samples directly from inside rail cars before unloading the concentrate. After testing and comparing the results with the conventional sampling method, the bulk product sampler proved to be a practical and advantageous solution for concentrate sampling both for the customer and smelter. Since its installation at the Horne smelter in Rouyn-Noranda, the Bulk Product Sampler has been steadily used on rail cars which contain concentrates from around the world."

Jan 1, 1996

By D. G. Cerigo, D. M. Bryce, P. H. Jennings

This paper summarizes the results of an experimental and economic study undertaken to evaluate the feasibility of treating an oxidized orebody of about 10 million tons, grading about 0.75 per cent copper, by agitation leaching and by percolation leaching.

Jan 1, 1968

By P. G. Sprang, S. Rosen

The Y-Al- C ternary phase diagram for the com -position range from 55 to 100 at. pct Y and for a temperature of 950°C has been constructed from metallographic and X-ray diffraction data. The significant features of the isothermal section which is presented are the small solubility of aluminum in the binary Y3C phase and the presence of a ternary carbide phase with a small homogeneity range around the composition Y3AlC. The similarity in structure and composition between these two carbide phases is discussed in the light of the misci-bility gap which exists between room temperature and 1300°C, which was the temperature range studied. THE occurrence and stability criteria of ternary T3BC, carbide phases having the L&apos;12 structure and the general formula T3BCx have been discussed in detail by stadelmaier1 and more recently by the present authors., Stadelmaier found many representatives of these phases formed between the T metals Mn, Fe, Co, and Ni and the B metals Mg, Al, Zn, Ca, Ge, Cd, In, Sn, Hg, T1, and Pb. The present authors reported on a new series of iso-structural carbide phases formed between the T metals of the Sc group and the B metal, aluminum. These new phases are unique in that many of the Sc group elements form stable binary carbide phases which occur about the composition T3C and which crystallize with a structure similar to that of the T9BCx ternary carbide phases. Furthermore, these binary and ternary phases are found to coexist in equilibrium with each other. The similarity in structure and composition between, for example, Y3C and Y3AlC in the light of the mis-cibility gap which had been found to exist between these two phases indicated a need for a more thorough knowledge of the phase relations which occur in alloys based upon these compositions. Consequently, an investigation of the phase equilibria in the yttrium-rich portion of the Y-A1-C phase diagram was undertaken. The limiting Y-A1 binary diagram determined by Lundin and Klodt3 and the results of Spedding et al.4 governing the Y3C phase were used as guides in , constructing the diagram. EXPERIMENTAL Alloys weighing about 10 g were prepared by arc-melting powder compacts made from the various components on a water-cooled copper hearth using a tungsten electrode in a gettered argon atmosphere. Good homogeneity was obtained by melting the alloys three times. The purity of the yttrium used was 99.9 pct (0.07 pct rare earths). The purity of the aluminum and the carbon was 99.99 pct. The results of chemical analysis on five representative alloys showed that losses during the alloying process were predominantly carbon losses and that in no instance did the measured concentration of this component differ by more than 3 at. pct from the intended composition. For this reason the alloy compositions which are reported are those of the charges prepared for melting. Three alloys which were analyzed for copper, tungsten, nitrogen, and oxygen compositions showed that no contamination had occurred either during casting or during the subsequent annealing treatments. For the major part annealing treatments were carried out on specimens which were placed in

Jan 1, 1965

Jan 1, 1950

By Thomas Brownfield

Development and production activity in Oklahoma during the year 1940 was of routine nature. Production, according to the Corporation Commission&apos;s figures, averaged 409,100 bbl. daily as compared with 421,000 bbl. for the year 1939. Discoveries were of minor importance except for the Cumberland pool in Marshall and Bryan Counties, in the southern part of the state. Maintenance of a relatively stable producing rate is attributable to the drilling of new wells and the recompletion of many old wells in the previously established producing areas. During the year 1785 new wells were drilled, a decline of approximately 10 per cent as compared with the previous year. Of the wells drilled, 962 were oil wells with a combined initial production of 241,000 bbl. daily, 172 were gas wells having aggregate capacities of 1205 million cu. ft., and 651 were dry holes. Wildcat activity increased 20 per cent over 1939 and 227 such wells were completed during the year; that isl 43 oil wells, 16 gas wells, and 168 dry holes. In addition to the new work completed, 603 wells were recorded as having been drilled deeper or plugged back to test new horizons; included were 334 producing wells with total initial production of 65,000 bbl. daily, 37 gas wells with initial aggregating 305 million cu. ft., and 232 abandonments. Footage drilled amounted to 4,730,000 ft., an average of 2650 ft. per well as com-pared with an average depth of 2600 ft. recorded the previous year. The principal new pools discovered as a result of the exploratory drilling were Cumberland; East Cromwell, in Okfuskee County, and Prague, in Lincoln County. At the end of the year Cumberland had 13 completed wells, which averaged 700 bbl. initial through tubing from the Simpson Bromide formation (Ordovician) at 4750 ft. East Cromwell had 10 wells with average initial of 435 bbl. in the Cromwell sand (Pennsylvanian) at 3460 ft. Prague had II wells with an initial average of 220 bbl. from the Senora sand (Pennsylvanian) at 3260 ft. There were notable extensions to the Dill pool, Okfuskee County, and to the Hewitt pool, Carter County. At the end of the year, 19 producing wells had been drilled in the former, with initials averaging 1000 bbl., and 63 wells averaging 150 bbl. daily in the latter. There were no notable changes in the policy of State conservation authorities with respect to proration. The Bureau of Mines recommendations for the year averaged 413,000 bbl. daily; the State author-ities fixed allowables at an average of 406,000 bbl. daily, while, as noted above, production averaged 409,100 barrels. The most important development in the older areas occurred in the following pools: Billings.—Seven oil wells with an average initial production of 2500 bbl. and two dry holes were completed during the year. Production from the Simpson horizon averaged 6025 bbl. daily as compared with 5950 the previous year. Production from this field has been almost steady since reaching its peak early in 1937. The major portion of the pool is efficiently operated as

Jan 1, 1941

By Chappel R. A, Fishburn B. R

The Eastern Distributor Tunnels - the first major road tunnel project in Australia - are the preferred solution to traffic congestion problems, when compared with alternatives, in this inner urban environment. This is because of the reduced impact on residential housing, the improvement of the existing environment, less restrictions on future developments, and a reduction in noise and pollution. Developments leading to a tunnelled solution, traffic needs and reasons for route location are discussed. Criteria for design of tunnel alignments and geometry are described, including the restraints imposed by surface connections on profiles and grades resulting in low rock cover at tunnel portals. The main geotechnical restraints are a major weathered dyke at the shallow large span underground fork and the weathered Ashfield Shale capping the Hawkesbury Sandstone at a portal. Rock cuttability and excavation methods are discussed. Roadheader machines are the most suitable for the varying shallow arched cross sections required and the tunnel lengths involved but the use of blasting in special situations cannot be ruled out. Initial support for the major tunnel lengths will be provided by rock reinforcement in conjunction with shotcrete. Steel ribs are proposed in areas of low cover and weak ground. Final support will comprise an insitu concrete lining. Construction concepts and special tunnelling methods required at the shallow underground forks and tunnels are described.

Jan 1, 1987

After some 50 years of worldwide research in relation to coal pillar mechanics and design as well as numerous workshops and technical papers related to these issues there is still some significant disagreement as to the approach one should adopt in the assessment and design of a coal pillar. Of course there are many different types of coal pillars that fulfil a wide range of roles at any particular mine and in this instance it is appropriate to have a &apos;tailored&apos; approach for each pillar type in relation to the role it fulfils. However where it can become very difficult for the mine operators is when various researchers or consultants use or recommend significantly different approaches for the same type of pillar fulfilling the same role. By 1999 two pillar design techniques had been developed specifically for the Australian underground coal mining industry (ie The University of New South Wales Pillar Design Procedure, UNSW PDP and Analysis of Longwall Tailgate Serviceability, ALTS) and several other pillar design techniques were being practiced by individual consultants. The Australian industry hoped to resolve the issue of what technique to use for each pillar type and role, when it funded UNSW in 2000 to develop a &apos;Systems Approach to Pillar Design&apos;. The findings of the abovementioned project were published in 2005 and while every attempt was made by UNSW to include the views of various local and overseas researchers and consultants it would be fair to say that a unified approach to pillar design in Australia was not adopted as a result of that project. This is the experience of one country where there has never been one central group solely undertaking such research in relation to pillar design (such as the Chamber of Mines in South Africa). This paper explores the Australian experience in terms of pillar research and what that experience may offer to researchers in Australia and other countries. At the First Australasian Ground Control in Mining Conference (2003) the first &apos;update&apos; of the ALTS Design Methodology (ie ALTS II) was presented. In subsequent years the ALTS database was continually updated and significantly expanded such that it now includes detailed information in relation to both the tailgate (148 cases) and maingate belt road (58 cases). In addition to tailgate roof support and chain pillar design, the current version of ALTS (referred to as ALTS 2009) includes a maingate belt road roof support design module. This paper is also intended to update and summarise the development and application of the ALTS Design Methodology for longwall gateroad design over the last decade both directly and in the context of coal pillar research conducted in Australia over the last 15 years.

Nov 25, 2010

By L. G. Truby

This paper presents the results obtained after calculating matches of the observed pressure performance of five fields completed in a common aquifer. A general dejcription of the Central Basin Platform area in West Texas in which the five fields, Andector, Embear, Martin, TXL, and wheeler, are lo. cated is contained in the paper. The method of utilizing the electric analyzer to calculate simultaneously matches of the observed pressure performance of the five fields is outlined. The determination of boundaries of pressure communication is discussed and the extent of pressure interference between fields consistent with the configuration of the area aquifer is shown graphically. INTRODUCTION Anomalies in the pressure performance of the Andeector Ellenhurger Field resulted in an investigation of pressure interference between several Ellenburger fields located on the Central Basin Platform in West Texas. Four fields, Embar, Martin, TXL, and Wheeler, were found to contribute significantly to the pressure drawdown at Andector. An initial investigation of the pressure performance of the Andector Ellenburger Field revealed that the reservoir pressure could not be matched by the calculation technique usually applied to water drive reservoirs. In the past, many have advanced the opinion that fracturing in the Ellenburger was a local condition restricted to the immediate uplifted area around the field, in which case each field would in all probability be surrounded by its own relatively small aquifer. Following several unsuccessful attempts to account for the pressure performance at Andector, a system assuming a common aquifer involving several fields in the immediate vicinity of Andector was placed on the electric analyzer and the effect of lo. interference was noted. A refinement of the initial analyzer calculations involved the determination of the approximate boundaries of the aquifer, the calculation of detailed matches of the pressure performance of the interfering fields, and an evaluation of the degree of communication between fields. DISCUSSION Geology and Development The fields considered in this work are located in the Central Basin Platform, a north-south trending structural feature in West Texas lying between the Delaware Basin to the west and the Midland Basin to the east. The locations of various individual Ellenburger fields in this general are shown in Fig. 1 with the five major fields which appear to be definitely intercommunicating colored in black and located in the circled portion of the figure. Production from the five fields was first obtained from the Embar Field discovered in July 1942, followed by the Wheeler Field in 1943, the TXL Field in 1945, and the Martin and Andector Fields in 1946. The total reservoir fluid production from these fields is indicated in Fig. 2. As illllstrated in this figure, very little production was taken from these fields prior

Jan 1, 1952

By A. Niedbalska

A technique was developed for low pressure diamond synthesis using a specially prepared glassy carbon. The glassy carbon is produced in the form of solid plates by slow carbonization process of phenol formaldehyde resin interrupted at temperatures of 1273° K, 1073° K, and 923° K. The diamond synthesis is performed using cobalt plates as a catalyst-solvent. Synthesis was carried out at applied pressures of 6.0 and 3.8 GPa and a temperature of 1970° K and 2170° K. The products were analyzed by the x-ray powder dyffraction method and by microprobe to identify the diamond crystallites. The samples were taken from the place of contact between the glassy carbon and the cobalt catalyst. They were separated from the charge by a chemical method. Diamonds of the best form and the largest size were obtained at pressures that were much lower than those used in the traditional graphite method of diamond synthesis.

Jan 1, 1989