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By M. R. Yalamanchili, W. H. Jang, Y. Ye, J. D. Miller

Typically, rougher molybdenite flotation and recovery from bulk copper/molybdenum concentrates involves the use of alkalisulfides, Nokes reagents, cyanides, oxidants, and/or thermal treatment to depress copper sulfide minerals. The bulk copper/molybdenum feed generally varies from 0.2% Mo to 1.0% Mo, and with traditional reagents the single-stage rougher flotation recovery of molybdenite varies between 40% and 90% at a concentrate grade of 5% to 10% Mo. With ozone conditioning for copper depression, however, improved separations appear to be possible, as demonstrated by tests with Cu/Mo concentrates from both the Phelps Dodge Morenci Operations and the Kennecott Copperton Operations. Single-stage rougher flotation after ozone conditioning can provide a molybdenum concentrate at a recovery of more than 90% and a rougher concentrate grade higher than 20% Mo in some cases. Subsequent cleaner flotation with additional ozone conditioning resuIts in relatively copper-free molybdenum concentrates containing as much as 52% Mo. Preliminary analysis indicates that, with a multistage ozone conditioning/fotation strategy, the process is technically and economically viable and should be suitable for industrial ap¬plication.

Jan 1, 1991

By K. Narayana Swamy

The traditional approach to improving the operating efficiency of a metallurgical plant has been to study individual unit operations and focus on improving the poor-performing unit operations. The complex nature of most metallurgical plants call for a holistic approach that will consider the whole rather than just focus on the individual units of a plant. This holistic approach is part of the systems thinking principles. Numerous case studies highlight the importance of the need to apply systems thinking principles in improving the effectiveness of metallurgical operations. Improving the efficiency of one unit operation without considering its effect on the performance of other unit operations has in many cases lead to lower overall operational efficiency. Modeling and simulation are key to the application of the systems thinking principles. Standard flowsheet models are very useful in scenario analyses though they have to be supplemented with other models for useful predictions.

Jan 1, 2006

Study on Basic Theory of the Grain Settlement in Fluidised Bed This paper takes thick goal grains (less than 1.5 cm) as research object. According to different densities and particle sizes, thick goal grains are divided into 20 kinds of narrow density and narrow size level average grains. Free settling and hindered settling tests are respectively carried out in ?100 fluidised bed thick goal separators. Hindered settlement includes hindered settling velocity test and measurements of suspension density. Results show follows. (1) Fluid state in separator belongs to transition region. Alien's law is the appropriate formula of thick coal particles free settlement terminal velocity. (2) The main factors affecting hindered settling velocity are the number of solid particles in medium and the structure feature of the particle group. The bigger volume fractions of solids ? is, the smaller decreasing velocity coefficient of particle hindered settlement ¯ becomes. In the organism from bottom to top, density of suspended particles in fluidised bed gradually decreases, but near the top of the suspended particles, the density increased slightly. With increase of density and size, suspension density reducing extent increases from bottom to top of separators.

Sep 13, 2010

By C. E. Shoenfelt

Wildcat drilling in the Rocky Mountain region did not suffer as large a decline in 1942 as was anticipated. The drilling program laid out by the Government at the beginning of the year stressed wild-catting operations and called for reduction of drilling in proved fields. The increased wildcatting campaign did not yield a great many new discoveries, nor important extensions to old fields. Several interesting wildcat wells were drilled in Colorado in 1942 but no new fields were discovered. The Wilson Creek field was extended and about 400 acres added to its reserves. In Montana two new oil fields and two small gas fields were discovered. The developments in the marketing situation had improved, however, making the prospects especially bright for 1943, as will be shown presently in the section on Montana in this report. In New Mexico eight wells were completed, which constituted discoveries ol either oil or gas but none of these was of major proportions. In Wyoming one new oil field and one new gas field were discovered, and one old oil field and one old gas field were extended. Most important was the disco-very of prolific oil producers in deeper sands in three old oil fields, of which one at least, Elk Basin, probably is of major proportions. Government Action On Dec. 26, 1942, President Roosevelt signed the O'Mahoney bill, calling for a flat 12.5 per cent royalty on lands in the public domain. It is expected that the enactment of this bill will encourage wildcatting in the public land states. Opportunity for a full discussion of the problems of reserves and production was afforded at the hearings conducted on the O'Mahoney bill by the minerals subcommittee of the Senate Committee on Public Lands and the statements submitted at these hearings last fall placed the situation, its causes and the logical remedy, clearly on record. It was established at the hearings that for several years the volume of oil discovered per wildcat well drilled has steadily declined; new fields discovered have not been of major proportions; drilling costs have advanced rapidly; a sharp decline in exploratory drilling took place in 1942, while the proportion of dry holes increased; the inescapable conclusion is that to find new reserves the search for oil must be intensified and much more wildcat drilling ' must be done. To ensure an adequate drilling campaign, the Petroleum Industry War Council, the Interstate Compact Commission and other representative oil organizations have voiced by resolution their opinion that an upward revision of crude prices is necessary to provide an incentive to the prospector to undertake the hazards of wildcat drilling, since statistics prove that only ope in five or six wells drilled results in actual production. Former Price Administrator Henderson rejected the recommendations for price increases and declared himself unalterably opposed to a general price advance, On the ground that such advances would contribute to inflation. Now that Mr. Hender-

Jan 1, 1943

By Guanghui Li

Nickel pig iron (NPI), used as a substitute for electrolytic nickel, is able to reduce the production cost of stainless steel greatly. Aiming for preparing NPI from nickeliferous laterite ore, a pilot-plant scale test of coal-based rotary kiln direct reduction of laterite ore was performed and reported in this study. In this process, the ground laterite sample (18.85% TFe and 1.52% Ni) mixed with additives, pulverized coal and binder was briquetted into briquettes with the size of 40mm×40mm×31mm, laterite ore briquettes and reducing coal were charged into a rotary kiln with the diameter of 1.6 m and the length of 16 m, for a retention period of 6~7 hours, in which reduction section temperature was ranging from 950~1050 oC. The reduced briquettes were water quenched, ball mill ground and beneficated via low intensity magnetic separation. A magnetic concentrate, Ferronickel powder, with 86.9% TFe and 8.0% Ni was obtained, and the corresponding magnetic recovery of iron and nickel are 75% and 96.3%, respectively.

Jan 1, 2014

By M. Karmis

For several centuries surface subsidence has been recognized as an inevitable consequence of most underground mining. In fact, British court records of disputes and litigations related to property damage due to mining subsidence can be traced to the early fifteenth century (Shadbolt, 1978). The first systematic investigations of the mechanisms involved in mining subsidence can be credited to Belgian Mining Engineers. The re- search effort was initiated after the widespread movements and the resulting structural damages suffered by the City of Liege in the 1920's. The publication of Gonot's 1871 treatise "Loie de la NomZ" (normal theory) was one of the most not- able achievements of the Belgian school of that era (Gonot, 1871). During the past 100 years the phenomenon of mining subsidence has been the subject of intensive research, particularly in Europe where long- wall is the most common method of underground coal mining. Many theories have been advanced to explain the mechanism of ground movement as it develops from the excavation, through the superincumbent strata, to the surface. Such theories include the original concepts of beams, arches, domes and the contemporary mathematical modeling principles of strata movement assuming two extreme concepts-- a continuous elastic medium and a stochastic medium for the superincumbent strata. An excellent review of the development of these theories ?-s given by Shadbolt (Shadbolt, 1978). In conjunction with the theories of mass strata movement in the vicinity of mine workings, the subject of surface subsidence predictions has also been the subject of extensive research. The development of reliable and rational techniques of subsidence prediction is imperative, if this phenomenon is to be recognized and controlled within acceptable environmental levels. Empirical as well as mathematical methods have been proposed to fulfill this objective and a comprehensive analysis of these methods has been presented in the literature (Bramer, 1973; Shad- bolt, 1978; Virginia Polytechnic Institute and State University, 1980). As a result of this intensive research effort, it is now accepted in many )coal fields-- mainly in Europe-- that the state of art in subsidence prediction and control has approached a level where mining induced surface displacements can be predicted to a suggested accuracy of less than + 20 percent. Furthermore, such movements can be translated into anticipated structural failures using established damage criteria, thus enabling appropriate precautionary measures to be implemented. In this country, subsidence is rapidly gaining emphasis as an important environmental problem of underground coal mining. Damage resulting from this phenomenon ranges from land settlement to severe structural damage and has been witnessed in rural (Illinois, Colorado, West Virginia, Virginia, Pennsylvania) as well as in urban areas (Pennsylvania, West Virginia, Illinois, Wyoming). Yet, the art of subsidence prediction and hence control in this country, for both longwall and room-and-pillar coal mining, is far from approaching the maturity reached by the Europeans. In this paper, field measurments and computer modeling techniques have been used to develop some basic relationships of longwall subsidence and its related parameters. Because the objective of this study was to develop regional subsidence trends, all processed information pertains to the Appalachian coal region.

Jan 1, 1981

By Foudoulis C, Smith CB, Drew RM, Sun S-S, Sheraton JW, Hall AE

Primay (syngenetic and protogenetic) inclusions - i.e. minerals formed during or before diamond growth and encapsulated in the diamond - provide important information on the origin of diamond. Recent Rb-Sr and Sm-Nd dating of such inclusions has yielded crystallization ages older than their volcanic host, implying that diamonds are mantle xenocrysts. In this paper we report results of studies on the nature of syngenetic inclusions and the carbon isotopic compositons of the host diamond from the West Australian diamond deposits at Argyle and Elllendale. The Argyle diamonds are dominantly, of eclogitic paragensis and are characterized by strongly C depleted compositions. We have recognized an association of stone morphology, inclusion type and carbon isotopic composition amongst the Argyle stones, and on the

Jan 1, 1989

By Francis Kendorski

The mining engineering design professional has limited practical and reliable tools for planning successful room-and-pillar stone mines using readily-available and collectible information. Three techniques are in common use today: the hard rock CANMET method of Hedley and Grant, the hard rock method of Stacey and Page, and the oil shale method of Hardy and Agapito. Other methods have been proposed, such as the USBM method of Obert and Duvall, the CSIR/Penn State method of Bieniawski, and the soft rock confined core method of Abel, Wilson, and Ashwin. However, the latter have practical shortcomings when applied to room-and-pillar stone mines such as developed for construction aggregate production. Ideally, the use of multiple techniques resulting in the same acceptable and reliable answer is the goal. Recently, in several underground stone mines areas of undersized pillars were examined. These undersized pillars apparently resulted from non-adherence to a mine plan. These undersized pillars now exhibit strong evidence of incipient failure such as slabbing, opening of through-going fractures, and hour-glassing. This situation allows examination of pillar designs at a ?safety factor? of essentially one. This rare opportunity allowed the examination of the suitability and adjustment of the first three design methods discussed, resulting in greater overall confidence in the methodologies.

Jan 1, 2007

By P Andrieux

By 1996 ground control-related problems at Brunswick Mine had raised serious concerns regarding the safe and economical extraction of large portions of the reserves. These difficulties were mainly caused by high stress levels in pillars, instabilities resulting from wide spans supported by ageing support elements, and chronic difficulties supplying rock fill from the surface quarry to the underground workings, which resulted in many large voids remaining open for long periods of time. Significant changes have been implemented at the site since 1996, amongst which were a change of mining method, the introduction of paste backfill, the establishment of stress management measures, and the introduction of shotcrete on a large-scale. This paper focuses on the regional ground conditions associated with both the previously used primary-secondary mining method and the newly implemented pyramidal pillarless technique, as well as on some of the stress management measures implemented at the mine.

Jan 1, 2000

By Hare S. M, Griffin P. T, O&apos

Chalcopyrite ore and converter slag treatment to produce copper concentrates is undertaken at the Copper Concentrator of Mount Isa Mines Limited. This concentrator was commissioned in May 1973, replacing the original No 1 Lead-Zinc Concentrator, for the processing of all chalcopyrite ore coming from Mount Isa Mine.Treatment of chalcopyrite ore at rates of up to 125 000 l/week is described here; the treatment of converter slag is described later.

Jan 1, 1993

By Jacqueline A. McClaskey

The U.S. Bureau of Mines (USBM) Information and Analysis Directorate collects worldwide data on virtually every commercially important nonfuel mineral commodity. These data form the base for tracking and assessing the health of the minerals sector of the U. S. economy. The USBM's data collection activity was instituted by the 47th Congress in an appropriations act of August 7, 1882 (22 Stat. 329), which placed the collection of mineral statistics on an annual basis. The most recent authority for the USBM survey activity is the National Materials and Minerals Policy, Research and Development Act of 1980 (Public Law 96-479, 96th Congress). This act strengthens protection for proprietary data provided to the U.S. Department of the Interior by persons or firms engaged in any phase of mineral or mineral-material production or consumption.

Jan 1, 1994

By C. W. Spencer, J. Singer

A PARTIAL phase diagram for the As-Te system is given in Hansen.' The only compound reported is As2Te3, melting at 362°C. Stoichiometric quantities of reagent-grade elements were reacted in evacuated quartz and directionally cooled. The resulting ingot consisted of very thin threadlike crystals from which only very small single-crystal fragments were isolated. A powder diffraction diagram disclosed nonisomorphism with the analogous V-VI compounds insofar as these have been reported; Sb2S3, As2S3, Bi,S,, and Bi2Te3 data in the ASTM index of powder patterns, together with the single-crystal data on Sb2Se3,2 were used for the com- parison with the observed spacings. Single-crystal data confirmed the uniqueness of the As2Te3 structure. Single-crystal Weissenberg diagrams have so far yielded the following data: As2Te3 is monoclinic, space group C-m (OkO data still lacking), a = 14.4A, b = 4.05A, C = 9.92A, ß = 97". The cell volume is about 5802. The set of isomorphous ortho-rhombic cells of Sb2Se3, Sb2S3, and Bi2S, are apparently related to As,Te, in having one lattice constant close to 4.0 and with cell volumes as large as 540A8. Assuming Z = 4 for As2Te3 also, the density is calculated as 6.1 which agrees well with a roughly determined value of 6.0. A complete structure analysis is under way.

Jan 1, 1956

Organization Place Date 1917 American Institute of Architects Philadelphia,.,; Pa. Dec. 26-29 American Society of Mechanical Engineers New York City. Dec. 26-29 American Mining Congress State Chapter Phoenix, Ariz. Dec. 26-29

Jan 11, 1917

A test model is presented for the simulation of dewatering by gas injection of a porous aquifer above longwall workings. A finite difference model used in the oil industry was modified to match the underground mining conditions. The model is suitable to cope with the problem of dewatering reservoirs of low transmissivity. After comparing more versions, it has been concluded, that the investigated dewatering method can be proposed under special hydrogeological conditions only.

Jan 1, 1988

By John J. Secretary Egan

The present list of problems relating to the physical chemistry of steelmaking has been prepared by the Committee on the Physical Chemistry of Steelmaking, from answers to a questionnaire submitted to a number of metallurgists engaged in both industrial and educational work throughout the United States. The purpose of the project is to make available to research laboratories a list of problems, all reduced to their simplest terms, the solution of which would aid in creating a better understanding of the steelmaking process. It is not intended to restrict the problems to practical steelmaking. The list also includes the study of the properties, and their correlation, as well as the physical and chemical reactions, of all substances that occur or that may be in any way associated with steelmaking operations, such as metallic substances, refractories, nonmetallic inclusions, and the constituents of slags. Many of the problems can be carried out in university or other research laboratories. Others may be most successfully attacked by cooperation of the research men with the operating personnel. It is the Committee's earnest wish that this cooperation be fostered. It is requested that investigators who are working on any of the problems listed and who anticipate future publication of their results, notify the Secretary of the Committee that such investigation is in progress. Suggested additions to the present list are also requested. The Committee is undertaking to act as a clearing house for information regarding the topics in this field that are being actually studied. Interested persons are invited to correspond with the Secretary. I. Data involved in the state of equilibrium for the various systems (laboratory work, almost entirely). A. Specific heats, heats of formation, entropies and free energies of various PURE ELEMENTS OR COMPOUNDS; ALSO CERTAIN TYPICAL SLAGS AND REFRACTORIES I. Determination of specific heats and entropies of oxides, sulphides, nitrides, etc, over a wide temperature range. 2. Determination of free energies of oxides, sulphides, nitrides, etc., over a wide temperature range. 3. Determination of the heats of formation of the oxides, sulphides, nitrides, etc. 4. Determination of the thermodynamic properties of the more important mineral-ogical constituents of the basic open-hearth slags such as calcium silicates, calcium phosphates, calcium ferrites, manganese silicates, FeO and Fe2O3. 5. Determination of the specific heats of open-hearth slags, including liquid silicates, if possible.

Jan 1, 1941

By Armando Vazquez

This paper will provide an overall technology update on Tenova’s modular i BOF® technology package for improved endpoint detection (Carbon and Temperature), slop detection and auto-tapping control, with a primary focus will be on Tenova's Slop Detection System (SDS). Accurate Slopping prediction is a critical tool in the operation of a BOF. It provides the steelmaker with an additional protective system to increase yield & productivity while reducing operating costs. Tenova Goodfellow's i BOF® slop-detection technology uses lance vibration analysis with real-time alerts to give steel makers advance warning of the onset of a slop and a measurement of the slop severity. The system is designed to provide direct feedback control of lance position and oxygen flow rate, for rapid mitigation of potential slopping events. This paper will provide a summary on how the i BOF® technology package has been implemented, including trials and general results.

Jul 30, 2018

By K C. Williams, A W. Roberts, J D. Prigge

For stockpile design, the flowability and structural interfaces are critically dependant on the stress conditions throughout the pile. Historically, the predictive methodologies for stress determination have been too conservative, which adds inefficiency to the stockpile reclaim interface selections, especially for live reclaim stockpile systems. In addition, accurate pressure profiling throughout stockpile is essential to correctly design the stockpile support structures, which are buried within the stockpile. Such buried structures include trestle legs or columns to support load-out conveyors or the roof of bulk storage sheds. Improved methodologies with respect to the development of the hoop stress condition which exists in material ædrawn-downÆ within the stockpile has been developed. This hoop stress approach has significantly improved the live capacity prediction to over 90 per cent accuracy and improved rathole structure prediction within live reclaim stockpiles. Additionally the methodologies in estimating the vertical and circumferential stress variation acting on buried stockpile structures have been significantly progressed, with experimental testing shown good agreement with the theory.CITATION:Williams, K C, Roberts, A W and Prigge, J D, 2013. Recent developments in stress analysis and live reclaim prediction within iron ore stockpiles, in Proceedings Iron Ore 2013 , pp 501-510 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By Seshadri Seetharaman, Nurni N. Viswanathan, Haijuan Wang

The present work aims at some process modifications in specified metallurgical processes, wherein CO2 can be used successfully as an oxidant for decarburization in steelmaking and applied in some non-ferrous metals production processes. During the decarburization of Cr-containing high alloyed steels, the present researchers investigated the possible use of CO2 instead of Ar-O2 mixture and could successfully decarburize the steel melt without significant loss of alloyed Cr to the slag phase. A mathematical model was developed based on the bubble formation accompanying the chemical reaction: C(molten steel)+ CO2(gas)= 2 CO(gas). The model predictions were tested by laboratory scale (1 kg) experiments carried out in an induction furnace and very good agreement between the model predictions and experimental results were observed. A national project has been sanctioned in China for the implementation of CO2 in decarburization of ferroalloys as well enable the addition of pig iron in the electric arc furnace process when the scrap supply is limited. New processes have been developed for the utilization of CO2 in the case of non-ferrous processes. A novel method of treatment of Al dross by leaching with water and capturing the evolved NH3(formed by the hydrolysis of AlN) has shown very promising results.

Jan 1, 2015

By Peter K. Weissenborn, Robert J. Pugh

The contrasting behaviour of electrolytes in inhibiting coalescence of bubbles was explained by the positive and negative distribution of anions and cations at the gadwater interface. Further, the efficiency of electrolytes which do inhibit coalescence of gas bubbles can be linked to a counter ion hydration mechanism and the effect of electrolyte concentration on gas solubility. A correlation was found between the transition concentration of electrolyte needed to prevent the coalescence of bubbles and the reduction in gas solubility. Hence, the inhibition of bubble coalescence in electrolyte solutions appears to be linked with the utilization of water molecules in the hydration of cations and a consequent reduction of water available for gas solubility.

Jan 1, 1995

By Han-Tao Hu

Keywords: RH refining process, flow of molten steel, two-phase flow, gas holdup, circulation rate, mathematical modeling A three-dimensional mathematical model for the flow of the molten steel in the whole degasser during the RH refining process has been proposed and developed with considering the physical characteristics of the process, particularly the behaviors of gas-liquid two-phase flow in the up-snorkel and the momentum exchange between the two phases. The fluid flow fields and the gas holdups of liquid phases and others respectively in a 90 t RH degasser and its water model unit with a 1/5 linear scale have been computed using this model. The results showed that the flow pattern of molten steel in the whole RH degasser could be well modeled by the model. The liquid can be fully mixed during the refining process except the area close to the free surface of liquid and zone between the two snorkels in the ladle, but there is a boundary layer between the descending liquid stream from the down-snorkel and its surrounding liquid, which is a typical liquid-liquid two phase flow, and the molten steel in the ladle is not in a perfect mixing state. The lifting gas blown is rising mostly near the up-snorkel wall, which is more obvious under the conditions of a practical RH degasser, and the flow pattern of the bubbles and liquid in the up-snorkel is closer to an annular flow. The calculated circulation rates for the model unit at different lifting gas rates are in good agreement with the determined values.

Jan 1, 2005