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By T. Gupta, T. Ghosh

Rare earth elements (REEs) and their compounds are essential in a multitude of mundane and sophisticated applications such as renewable energy technologies, catalysts, medicine, and defense applications. The global supply deficit could be attributed to the destabilization of REE market that has, as a result, incentivized indigenous production of REEs. Cost-effective and environmentally benign opportunities are being explored for the production of REEs from non-conventional mineral sources including coal and coal by-products to stabilize the supply chain. Coal from Healy coal mine and Wishbone Hill deposits in Alaska have been quantified for REEs and were found to possess elevated total REE concentrations as compared to world average levels (60– 70 ppm). The objective of the study was to concentrate the REEs in the froth phase by froth-flotation of the fine size fraction (< 75 μm). A Box-Behnken design of experiment was employed to ascertain the main and interaction effects of operational parameters on response variable by analyzing 3D response surfaces. Experiments were carried out to maximize REE recovery and concentration by modeling and optimization of three operating variables (frother dosage, pulp density (% solids), and collector dosage). Based on the results, the optimum flotation conditions for maximum recovery at an elevated concentration of REEs in the froth fraction was obtained at 4.2% solids and 32.7 ppm of frother dosage for Healy sample and 10% solids and 37.9 ppm of frother dosage for Wishbone Hill coal sample. The quadratic relationship between the input and response variable was found to be independent of collector dosage suggesting good surface hydrophobicity and floatability of the two coal samples.

For tax purposes a mining company is a New Zealand company whose principal source of income is from the business of mining, or exploring for certain specified minerals in New Zealand. New Zealand tax law distinguishes between a non-resident mining operator and a mining company, with the only major difference in tax treatment being the corporate tax rates. New Zealand mining companies are taxed at 28 per cent, whereas non-resident mining operators are taxed at 33 per cent of taxable income. These provisions also apply to the petroleum mining industry. Individuals who carry on the business of mining are also specifically defined in the Act. They are termed as &apos;resident mining operators&apos;. Non-resident mining operators are non-residents of New Zealand who carry on mining ventures as a business in New Zealand. Mining ventures are defined as the exploring, searching and mining of specified minerals, including development work carried out for profits. Similar provisions apply to the petroleum mining sector. Specified minerals are defined in the Income Tax Act 1976 (&apos;the Act&apos;) and while no useful purpose is obtained by listing them in the paper, they include a larger number of industrial and commercial minerals. The Minister of Finance is also empowered to add to the list by publishing his determination in the Gazette.

Jan 1, 1988

By Lindsly. Ben E.

"The recovery or partial recovery of the oil remaining in oil sands after the usual methods of production have become unprofitable is perhaps the greatest problem in the petroleum industry today. The amount of this oil remaining in the sand is variously estimated by those familiar with the subject to be 25 to 90 per cent of the original content.2Lewis3 states, ""The estimate of 80 to 90 per cent of the oil left underground does not seem incredible.""It is estimated by the writer that approximately 91 per cent of the oil originally held in the Elliott pool, was still in the formation on January 1, 1924, and that it would take at least 12 years, at the 1923 rate of production, to further reduce this quantity by one per cent of the original content.The progress made in the oil industry during the past few years relative to the prevention of evaporation losses; to improvement in cracking processes, whereby the gasoline yield from many crudes has been doubled and trebled; to the increased recovery of gasoline from natural gas; and many other developments, remarkable as they are, can be applied only to that comparatively small portion of petroleum products which are raised to the surface. A device or process which would cut development costs to one-half would probably result in a much smaller profit to the oil industry, than the profit derived from an additional 10 per cent recovery of the total amount of oil in a pool. Various methods have been used and many others proposed, for the increase of oil recovery from normally depleted sands.In France, oil sands are being mined by means of shafts and galleries. In other places, notably the Bradford, Pennsylvania field, the yield has been increased by means of water flooding, wherein water is introduced into the sand to displace oil, and drive it to producing wells."

Oct 1, 1926

By D. W. MacFarlane

In the formation of Oil and Gas Producing Units lawyer& and engineers are interdependent members of the same team. Management is, there-fore, entitled to expect no less than a total cooperative effort from the members of these professions. The petroleum and natural gas lawyer must diligently inform himself on the implications of engineering evidence. Otherwise he can be of little assistance to his engineering witness in a thorough, systematic and convincing presentation of his technical evidence. Conversely, the engineer must appreciate the concern of counsel that quasijudical hearings, whether technical or otherwise, be con-ducted in such a manner as to pre-serve some semblance of organized judicial procedures in the adjudication of property rights. The principal problems in unitization are the participation formula and the adjustment of investment in unit facilities. The equating of oil to gas, the effect of unit infill drilling, the relative values of producing zones and well productivity have •been controversial factors in several Saskatchewan units to date. Perhaps the most perplexing of these has been well productivity. While preserving current income, it may also preserve an ability to drain adjacent tracts plus an inequitable sharing of .reserves properly attributable to secondary recovery operations. However, inequity may also result in depriving an operator of the benefits accruing to him under competitive operations by virtue of his favourable reservoir position or his use of advanced production techniques. The Saskatchewan Oil and Gas Conservation Act has been construed by the Department of Mineral Resources as •completely negating any benefits inherent in the rule of capture when determining equities under unit operations. Under adjustment of investment provisions, large cash flows between owners of exploited acreage should be avoided upon the creation of a unit. These provisions should not deprive any company of the benefits it may have obtained under competitive operations in producing its fair share of the reservoir at a lower net cost per barrel than its competitors. Unitization should be concerned with physical conservation rather than in equalizing production costs as between operators.

Jan 1, 1960

By M. T. Thomas

Sufficient development of the X-Ray Photoelectron Spectroscopy (XPS), the Auger Electron Spectroscopy (AES), and the Secondary Ion Mass pectroscopy (SIMS) has made these instruments ideal for solving problems related to mineral processing -particularly gold ore processing. XPS can determine both the surface composition and chemistry of ores and tailings, and the various phases within either of them. AES can also determine surface composition with the further advantage of having greater spatial resolution so the surface chemistry associated with specific minerals in the ore can be identified. This identification helps to clarify why some minerals pass through a chemical process unaffected, while others can be successfully treated. SIMS has an elemental sensitivity from one to four orders of magnitude greater than XPS or AES which makes it useful for detecting the presence of some elements in very low concentration (parts per million).

Jan 1, 1981

By R. E. Robinson

A novel variation of the GYPCIX process for the treatment of the acid mine effluent water from Grootvlei is described, in which a number of valuable by products can be obtained and the product water can be used for a variety of different purposes. A conceptual case study is presented in which the important cost parameters are described and certain critical path activities are indicated in order to derive a Return on Investment evaluation according to methods previously published. The study indicates that the treatment costs can be dramatically reduced, provided that proper utilization of the by products is taken into account. There are many possible uses for the water. However, by far the most advantageous contribution to the RDP and the best return on capital is derived if the water is used to establish small-lot farming activities providing work opportunities for thousands of people and contributing several hundred million Rands to the GDP. Vastly improved social conditions will be generated in an area of Gauteng that is in danger of rapid deterioration and a contribution will be made to maintaining mining activities in this area. The environmental impact is positive.

Jan 1, 1998

By AIME AIME

THE Coal Division holds its fall meeting in the Pocahontas coal field, at the West Virginian Hotel, Bluefield, W. Va., Oct. 9 and 10. The first day will be a busy one-two sessions for the presentation of papers and a dinner in the evening. Hon. E. Fudge, Assistant Undersecretary, Mines Department, and R. V. Wheeler, head of the Mines Research Board of Great Britain, will be the guests of the Division. Mr. Wheeler will discuss the British Mining Act as relates to the coal industry. George S. Rice, Chief Mining Engineer, U. S. Bureau of Mines, will present an account of the recent meeting at Buxton in England, of representatives of England, Germany, France, Belgium and the United States to formulate a plan and to correlate research work now in progress in the various countries. The second day the members will be the guests of the operators on a trip through the Pocahontas field. The work of preparation for the meeting is being actively pushed by committees headed by T. H. Clagett, R. M. Lambie and H. D. Smith, and a good attendance, both local and from the general membership of the Division, is anticipated. Because many will make the trip by car the principal automobile as well as rail-road connections to Bluefield are given here. The program for Friday, Oct. 9, follows:

Jan 1, 1931

By G. Konak

In-pit crusher location selection has had an important role recently, since increasing diesel prices. One way of reducing the haulage costs is to shorten the truck haulage distance by bringing the truck dump point into the pit. This study covers the work done on the optimum crusher location definition for a company that produces aggregate near Izmir, a city of Turkey located in the west. This paper will discuss the effects of pit geometry and mine access requirements on optimum crusher location selection that are mainly based on the establishment of minimum haulage distance. The method will be introduced first and then the computer algorithm developed for this study will be discussed later in the paper. Keywords: in-pit crushing, optimum location selection, optimizing haulage, computer aided design.

Jan 1, 2007

By Margaret R. Egan

The Bureau of Mines experimentally burned Pittsburgh Seam coal and other combustible materials found in mines in order to obtain a better knowledge of their emission products. These experiments were conducted in the Bureau&apos;s intermediate-scale fire tunnel, which simulates environ-mental conditions in underground mines. Smoke characteristics, gas concentrations, mass loss, and ventilation were measured. From these values, heat-release rates, particle sizes, obscuration rates, combustion yields, and production constants were calculated. This information was sought as part of a comprehensive study of combustible materials that will ultimately advance the design of more efficient fire detection and suppression systems. The coal combustion measurements presented in this report, together with previous analyses of wood and transformer fluid fires form a data base by which future studies of other mine combustibles can be compared.

Jan 1, 1987

By Carrol A. Quam

DURING the first years of operation of the titanium and iron mine of the National Lead Co. at Tahawus, New York, efforts to increase production were hampered by the increased load put on the facilities for sharpening churn-drill bits. The ore and rock are extremely hard and abrasive and it was necessary to sharpen and harden a large number of bits per day to keep the churn drills supplied. Efforts to increase the capacity of the bit shop by a two-shift operation were not wholly successful in that it was hard to train men to do a satisfactory job of sharpening and tempering the bits. The number of bits that were improperly tempered increased, thus boosting the daily requirements for bits at the drills and increasing the load on the bit-sharpening facilities.

Jan 1, 1949

By P. Schloth, H. van Swygenhoven, N. Chobaut, J-M. Drezet

"In the current trend toward thicker aluminium plates, a major concern is the stress build-up during quenching which causes distortions during machining. Indeed, cooling rates are not high enough, especially at the core of such thick plates, to prevent any precipitation and quench induced precipitates lower the hardening potential. Multi-scale modelling is required when predicting macro-scale stresses after quenching for thick heat treatable aluminium components. The reason is the instantaneous strong coupling between phase precipitation at the nano-scale and material hardening due to precipitation or softening owing to solute depletion at the microscale. For thick parts, quenching intensities decrease when going from the skin to the core of the component, thus introducing a gradient of nanostructure and consequently a gradient of mechanical properties. In addition, large thermally induced deformations lead to high macroscale residual stresses although part of them is relaxed by plastic deformation. These stresses have been measured in water quenched thick plates of 7040 and 7449 aluminium alloys using neutron diffraction and layer removal techniques and the results when compared with a thermomechanical finite element model of quenching highlight the influence of precipitation.IntroductionIn the processing route of heat-treatable aluminium alloys (AA), a critical step is quenching from the solutionizing temperature. High cooling rates are desired, as they avoid formation of coarse precipitates, which reduce mechanical properties. Fast quenching, however, cannot be achieved in the centre of thick components, where the quenching rate can be more than one order of magnitude lower than at the surface. The existence of a thermal gradient between core and surface leads to a differential thermal deformation which is accommodated by elastic and plastic deformation to comply with the compatibility of deformation. Whenever the material yields, especially at high temperature when the yield strength is low, residual stress remains after quenching due to the irreversibility of plastic deformation. After quenching, the plates are in a state of residual stress that causes unacceptable distortions during machining and may reduce service life drastically. Since stress relaxation is negligible during ageing treatments [1 ], agehardened aluminium parts are usually stress relieved prior to ageing. This is typically achieved by applying plastic deformation: stretching from 1.5 to 3 % in the rolling direction (L) can reduce the internal stresses by a factor of approximately 10 [2, 3]. However, complex geometries or thicker components like thick sheets require other approaches. Reducing the quenching rate by using boiling water for instance leads to lower residual stresses [1, 4]."

Jan 1, 2013

By Harold E. Rowen

Sintering is accomplished at a temperature of more than 2000°F. For the purpose of this discussion it will be defined as the art of burning a solid fuel with 90 to 95 pct ash content. Think of the problems of combustion involved in keeping a home furnace burning properly with 12 to 20 pct ash in the fuel and remember that the amount of fuel involved in the 5 to 10 pct combustion loss represented by the definition has to be just about right or nothing is going to happen. Our forefathers discovered that many ores containing metals csscntial to the steadily rising standards of living were associated with other minerals, sulfur and arsenic, for example, which had to be removed before ultimate refining. They did this by utilizing the solid fuels they had available-the sulfur or other readily combustible components- to create roasting heat.

Apr 1, 1956

By Rudolf Gahl

THE history of flotation in America is very short, at least as far as the large-scale application of the process is concerned. It is remarkable how many important developments have taken place inn the last few years and are already being extensively utilized. What was new a year ago, seems almost commonplace now. For this reason it is with hesitation that I follow the suggestion: of Dr. Ricketts, President of the Institute, to describe the experiences of the Inspiration Consolidated Copper Co. with the flotation process. TESTS CONDUCTED IN SMALL TEST-MILL When the Inspiration company first decided to build a concentrating plant, nothing was known about flotation, and the process was to be gravity concentration pure and simple. Demonstration Tests Conducted by Minerals Separation Co. While plans were being prepared by H. Kenyon Burch (who had been intrusted with the design and construction of the concentrator) the Minerals Separation Co., a concern at that time little known in America, asked and obtained permission to demonstrate the value of its flotation process for Inspiration ore. As. a consequence, a small 50-ton flotation machine of standard design was added to the company&apos;s test plant and started to operate in the beginning of 1913. This marks the beginning of flotation at Inspiration. The results obtained with this machine, which was operated by members of the Minerals Separation staff, so far surpassed what this company anticipated that it was decided to continue flotation tests for this purpose, and two of the flotation experts of the Minerals Separation Co., I. L. Greninger and G. A. Chapman, were retained. L. R. Wallace, now superintendent of the Miami works of the International Smelting Co., was at that time metallurgist of the Inspiration company and in that capacity took an active part&apos; in these tests. Great credit is due to him for his quick recognition of the possibilities of flotation.

Jan 9, 1916

By B. W. Howlett, M. B. Bever, Somnath Misra

The heats oj- formation at 0°C of the compounds AuSn,, AuSn2, AuSn, and the £ phase were measured in a metal -solution calorimeter with liquid tin or a liquid Sn-Bi alloy as solvent. The melting point, heat of fusion, and heat capacities near the melting point of- the compound AuSn in the solid and liquid state were measured in a constant temperature gradient calorimeter. The free energy and entropy of formation of the compound AuSn at its melting point and at 298 °K were calculated from the experimental results and published data. The heats of formation are discussed in relation to the nature of the compounds. The heat capacity below the melting point, heat of fusion, and entropy of fusion of AuSn are interpreted in terms of processes oc-curring before melting. The atomic arrangement in liquid Au-Sn alloys and the bonding in the intermediate phases of. the Au-Sn system are discussed in the light of the measured thermodynamic properties. THE available thermodynamic information on the intermediate phases in the Au-Sn system consists of the heats of formation of the compounds AuSn4, AuSn2, and AuSnly2 and of one composition of the < phase2 besides values of the heat content of the compound AuSn from 0" to 635".&apos; However, the heats of formation refer to different temperatures ringing from 90" to 450°C. Also, the reported error limits of some of the values are large and several inconsistencies are apparent. In the investigation reported here the heats of formation of the compounds AuS-, AuSnz, and AuSn and of three compositions of the < phase were determined for a single reference temperature of 0°C by liquid metal-solution calorimetry. The compound AuSn, which is the only congruently melting intermediate phase in this system, was further investigated in a constant temperature gradient calorimeter by measuring its heat of fusion, melting point, and heat capacity in the solid and liquid states near the melting point. From these data and published free energies of the liquid of composition Au~n,&apos; the free energies of formation of the compound AuSn at the melting point and at 298°K were calculated. The results shed light on the solid-liquid transition of AuSn and on the atomic bonding and state of association of gold and tin in the solid and liquid phases. 1) EXPERIMENTAL PROCEDURES 1.1) Preparation of Samples. Stoichiometric amounts of gold and tin, each 99.99+ pct pure, were melted in evacuated Vycor capsules (12 mm ID). The melts were maintained approximately 150°C above the liquidus for about 12 hr and shaken repeatedly. Samples of the compound AuSn were cooled slowly to room temperature. Melts of the other phases, all of which solidify by peritectic reactions, were transferred to the narrow end (5 mm ID) of the capsule, which was then quenched into iced brine. The solidified samples were annealed in the unopened capsules for 10 days at 30" to 50° C below the respective solidus temperatures. The absence of microsegregation and second phases was confirmed by metallographic examination. At least two batches of each composition were prepared. 1.2) Solution Calorimetry. The heats of formation were determined by liquid metal-solution calorimetry. In this technique, the difference between the heat effects on dissolution in a liquid metal, or alloy bath, of the compound and a mechanical mixture of its annealed components, adjusted for changes in composition of the bath, is the heat of formation of the compound at the temperature from which the samples are added. Details of the equipment and technique have been described."&apos; A tin bath at 300" or 350°C was used with the compounds AuSn,, AuSnz, and AuSn. The high gold content of the £ phase would have caused it to dissolve with an appreciable exothermic heat effect. In order to achieve thermal compensation, the samples were added from 0°C to a bath at 350°C consisting of 66.2 wt pct Bi (99.999+ pct pure), balance Sn (99.99+ pct pure). This solvent gives thermal compensation because gold dissolves exothermically in tin and endothermically in bismuth. The calorimeter was calibrated by adding from 0°C approximately 0.015 g-atom of the solvent.

Jan 1, 1965

By Stephen C. Tadolini, Steve Bessinger, James Pile, Christopher Mark

The San Juan Coal Mine, located near Farmington, New Mexico, supplies the San Juan Generating Station with more than 6 million tons of coal annually. To replace dwindling surface mine production, San Juan installed a longwall in 2002. The roof rock in much of the underground reserve consists of interbedded coals, carbonaceous shales, and mudstones. Roof support consists of fully-grouted roof bolts, both tensioned and non-tensioned, supplemented by modified cable trusses. Short-encapsulation pull tests conducted by San Juan’s geotechnical engineering department showed that some of the immediate roof layers provided variable bolt anchorage. To ensure that the roof bolts were obtaining the necessary anchorage, additional tests were conducted in a variety of locations. The results have been used to determine the optimum support design for different areas of the mine. Another series of tests evaluated the performance of several bolt and hole diameter combinations. The experience at San Juan Mine shows that short-encapsulation pull tests can provide the information necessary to improve ground control in variable roof conditions. It also illustrates how a pro-active geotechnical engineering program can be an essential component of a state of the art underground coal mine.

By P. T. Velu

Solubility of metal oxides in the molten salt electrblytes is an important parameter in the electrochemical processing of metals and alloys. The efficiency of an electrochemical process primarily depends on the quantity of metal oxide present in the electrolyte in the dissolved form and its thermodynamic properties. The activity of CeO2 was calculated using the free energy of fusion of CeO2,{ AG°m, CeO2. The AGOm,CeO2 }was deduced from the values of enthalpy, heat of fusion and melting point of Ce02. The activity coefficients of CeO2 as a function of temperature and melt composition were calculated. The thermodynamic data such as integral molar enthalpy, entropy and Gibbs energy of formation were calculated as a function of composition and temperature.

Jan 1, 1994

By W. D. Walker

All pipelines used to transport liquid fuels over coal mines are potentially hazardous; however, this publication deals only with dangers in transporting gasoline. Since transporting gasoline by this method is an established practice, the hazards connected therewith should he recognized by coal-mine operators and pipeline companies so that every known precaution may be used to reduce and keep the hazards to a minimum. The purpose of this paper is to direct the attention of coal-mine operators and employees, pipeline-company officials, and other interested persons to the explosion and fire hazards that arise from seepage of gasoline into underground mines. A hazard is not only presented in an individual mine when gasoline enters underground workings; but, in cases where mines are interconnected, a hazard exists in mach such mine.

Jan 1, 1954

By G. L. Oldright

THE metallurgist is familiar with the rapid development of concentration -by flotation and smelting in the reverberatory in recent years, brought &apos;about chiefly by the exhaustion of&apos; bodies of .rich, coarse, direct smelting ore. Geologically speaking, in many porphyry-copper districts, the richer contact or replace let deposits surrounding &apos;the main ore-forming igneous intrusion have been exhausted, and it is necessary to beneficiate the copper minerals disseminated throughout the mass of the intrusion itself. The organization of great companies to treat such low- grade ores on a large scale and the practices resulting from the necessity for an economic method of treatment &apos;are among the most prominent metallurgical developments of the past decade. It is interesting to note the effect of the present trend of practice on the inter-relationship of the concentrator and smelter, on the constituents of the smelter charge, and on smelting in general.

Jan 1, 1925

By Jon C. Volkwein

The U.S. Bureau of Mines has developed a method to measure methane and other gases during the auger mining of coal. An intrinsically safe commercial gas detector with a built-in data logger was mounted in the center of the hollow conveying auger. A sampling head through the wall of the auger conducted a gas sample to the detector. Results showed that gas levels can be monitored on a continuous basis during the auger mining of coal and the data retrieved upon completion of the hole.

Jan 1, 1994

By Rafael Lioji Kogake

O Alto Forno n° 2 é responsável por cerca de 40% da produção de gusa na CSN. Uma das principais utilidades responsável pela transformação do minério de ferro em gusa é o ar soprado que é fornecido por dois turbo sopradores da Central Termoelétrica n°2. Para que ocorra o processo de transformação do minério é necessário que o ar soprado seja aquecido. Isto é feito através dos regeneradores, os quais aquecem o ar para cerca de 1.300°C. Como cada regenerador tem um tempo de campanha, é necessário fazer a troca do mesmo a cada 1 hora. Nesse momento de mudança de regenerador, uma parte do ar soprado é desviado para o regenerador que está entrando em operação e ainda está vazio. Com isso, há uma perda pontual de produção indesejada, além de causar instabilidade no processo. A solução encontrada para reduzir este problema foi aumentar a vazão de sopro durante o período de troca de regeneradores, garantindo assim uma maior produção e melhor estabilidade do Alto Forno 2. Este trabalho apresenta o estudo do problema em questão, a metodologia utilizada para a sua implementação e os resultados alcançados.

Jul 31, 2018