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By Henry Schwellenbach

LABOR shortages, rising wages, and changes in moisture and fines content of the ore necessitated a review of the flowsheet at Warren Foundry & Pipe Co's. Mt. Hope, N. J. Mines Div. This plant had been designed prior to World War II, and started operations in January 1945. When this operation was designed there was an oversupply of labor in the area, wages were at a reasonable level, the run-of-mine ore was low in moisture, and there was a limited amount of fines. These factors all favored use of hand picking for cleaning rougher lump concentrate. Since that time, many changes have occurred. The proximity of defense industries and large military installations, has created one of the most acute labor shortages in the country. This labor shortage together with present wage levels, and the increase in moisture and fines in the ore created several problems. The increase in moisture and fines may be attributed to changed mining methods, the extensive use of sprays, and the opening of new mining areas bringing an increase in ground water. [ ] Two problems were presented by the increase in moisture and fines. The first was that lump ore arrived at the open hearth in an unacceptable condition, due to the segregation enroute of the large amount of fines that had adhered to the lumps. The second problem was that high magnetite content fines coated the large lumps, making it difficult for pickers to distinguish middling by other than the relative weight. [ ]

Jan 1, 1952

By Antti Porvali, Vivek Agarwal, Mari Lundström

Hydrometallurgical recovery of rare earth elements (REE) from NiMH battery waste can be performed using sulfuric acid leaching followed by selective precipitation as double salt (REENa(SO4)2·H2O) by adding Na2SO4 as a precipitating agent. The formed double salts can then be further converted with NaOH solution to form REE hydroxides. However, present literature has paid little attention to how to minimize the consumption of reagents in this recovery process. In the current study, a process model was built using HSC Sim software, and metamodeling of the simulated flowsheet was conducted with the design of experiments (DOE), after which the basic functionality of the flowsheet was verified by experimental work, starting from sulfuric acid leaching of spent batteries. As the process is based on chemical circulation internally in the process, the objective was to investigate the accumulation of the elements in solution, specifically Na+ , K+ , SO4 2− ions and impurities liberated in the NaOH conversion step. It was found out that metamodeling could be utilized in obtaining first estimate of the process behavior, prior to any experiments. Flowsheet functionality with circulated solution was confirmed, obtaining at best 96.9% La recovery.

By Monte J. Pool, Rudolph Speiser, George R. St. Pierre, William T. Ebihara

Standard free energies of formation of WO,, W O W20058 and WO3from oxygen and the lower oxide or tungsten have been determined in the tempel-ature range of 700° to 1220°C. A tentative W-O phase diagmm is presented based on the evidence that the oxide phases, "W18O49" and "W20058", are unstable at l~atm total pressure, below 585° and 485°C:, respectively. A HE need for a complete quantitative treatment of the phase equilibria of the W-O system has been establishedby metallurgists during the past few years. In an attempt to improve the endurance of tungsten exposed to oxidizing atmospheres at high temperatures, many research groups have studied the kinetics of tungsten oxidation. The reverse process, the reduction of the tungsten oxides to metal, has also been investigated to some extent. Regardless of the particular interest, metal to oxide or oxide to metal, a knowledge of the phase equilibria of the W-O system is required to properly interpret all of the kinetic observations. It should be possible to state the stable phases of the W-O system at any given values of the chemical potential of oxygen and the temperature.

Jan 1, 1962

By C. C. Nitchie, G. S. Brooks

With the gradual depletion of the natural-gas pools of the Kansas district, together with the uncertainty of further cheap fuel developments, some of the western zinc companies turned to the coal fields, attracted by their permanency and the success of the Matthiessen & Hegeler Co. and the lllinois Zinc Co. Being then confronted with the problem of using a relatively high-priced fuel, although the ultimate supply was very great, the fuel economies of the kilns and furnaces became of far more importance, and the more modern equipments, as a result, embodied distinct gaias in this phase of the business. In addition, there have been some pronounced advances in the actual making of gas from these coals. Increased efficiency in gas making has contributed its hare to lowering costs and those plants located in the higher priced fuel districts have probably been obliged to study these economies somewhat more closely. Naturally, many beneficial changes have resulted in both practice and apparatus in these sections. On certain western coals, for instance, the actual saving in fuel consumption has been 50 per cent. By this is meant that, where about 1.75 tons were burned to smelt 1 ton of oxidized ore, 0.7 to 0.9 ton is now required. While comparisons by T. R. Ingalls1 of fuel economies in smelting in this country and Germany before the war may, in general, be correct, they do not appear to do justice to the more progressive American practice. It is doubtful whether German plants were substantially bettering these fuel ratios. Data furnished by Bender and Frams do not afford records averaging less than 0.9 ton coal per ton ore on materials from 40 per cent. to 50 per cent. zinc. Fuels As producer fuel, Illinois, Indiana, and Kansas coah offer a wide range of material, although varying much in their amenability to gasscation. The proper fuel for each plant can only be determined after com-

Jan 1, 1920

By X. Q. Cui

The surficial collapse pits of the mining areas are continuously spreading in Beiminghe iron mine of Hebei Province as a result of the exploitation, which has done a lot of damage to the circumjacent ecological environment of the mine. It is a new path to handle the mine tailings at the present time that the thickened tailings are used to backfill the collapse pits, in which way the problems of the surficial collapse and the nowhere discharge of the tailings are both solved, and the rational utilization of the mine tailings and the clean production of the mine enterprise are realized. The?200 mesh content of the tailings of Beiminghe iron mine is 76.87%, and?325 mesh content is 63.50%. Semi-industrial dehydration experiments to the tailings have been done using the hydro-cyclone classified thickening process. The results show that when FX125 hydrocyclone is adopted, the concentration of underflow can achieve 73.31%, and the yield ratio is 61.78%; when FX150 hydrocyclone is adopted, the concentration of underflow is 70.57%, and the yield ratio is 54.31%, which indicate that the minor diameter hydrocyclone is propitious to improve the yield ratio of the underflow. The semi-industrial dehydration system of hydrocyclone classified thickening process is com-posed of FX125 hydrocyclone, D3600 high-efficient thickener and D2000 thickening bucket. The capacity to tailings disposal can achieve 3.07t/h and the tailings can be thickened from 28.86% to 62.45%. Compared with the traditional thickening-filtrating process and the total tailings directly filtrating process, the hydrocyclone classified thickening process has the merits of simple flow and high thickening efficiency, so it is easy to be realized in the mine.

Jan 1, 2014

By James R. Boyle

The value of Alabama's nonfuel mineral production in 1982 was $299.4 million, a decrease of $14.4 million from that of 1981; the decrease continued a downward trend that started in 1980. Output of most nonfuel minerals declined; cement, crushed stone, lime, sand and gravel, and clays were the major commodities produced in the State. Despite the decrease in mineral output, Alabama led the Nation in the production of crushed marble; was second in bauxite; third in ferroalloys and oyster shell; fourth in bentonite and dimension marble; fifth in common clay. fire clay, and kaolin; and sixth in masonry cement and lime.

Jan 1, 1984

By W. W. Kephart

The glass container industry is the largest producer of glass in the United States. As of this writing, there are approximately 89 active domestic production locations. In 1984, the industry shipped 11.8 million tons of glass containers. Approximately 70% of this production was clear or flint glass, 20% amber, 7% green, and the remainder miscellaneous colors. Although the production of nearly 12 million tons of glass is impressive, anyone following the industry over the last five years is aware that the industry has changed from a pattern of growth in the 1970's to one of maturity in the 1980's. Some observers, less generous, perhaps, have described the 1980's as a period of decline. In 1981, there were 119 production facilities which produced 13.2 million tons of glass the previous year. This equates to a 10% reduction in glass container production from 1980 to 1984, with a corresponding impact on the segment of the industrial minerals producers serving the container glass industry, as shown in Figures 1 and 2.

Jan 1, 1986

By A. H. Daane, J. F. Haefling

The limits of miscibility in some of the uranium rare-earth alloy systems have been determined in the temperature range 1000°to 1250°C. The solubilities of lanthanum and cerium in uranium are greater than those of the remaining rare earths by a factor of more than two. The solubility of uranium is greater in cerium, braseodymium, and neodymium than in the other rare-earth metals studied. The values found in this study are in qualitative agreement with those which might be expected if the solubility rules of Hildebrand and Scott are applicable. AS interest in nuclear reactors intensifies, many new types of fuels are being suggested in attempts to improve the economics of some of the proposed reactor schemes. To remove some of the difficulties inherent in the use of solid-fuel elements and their reprocessing, many types of liquid-metal reactors have been suggested. One of the more attractive features of several of these reactor concepts is that they include a continuous or semicontinuous process for the extraction of fission products and "bred" fissionable materials from the fuel, utilizing immiscible metal extractants. This would enable a much higher burn-up of fissionable material to be achieved and would present a very attractive economic picture. Several studies have been reported on equilibrium systems in which there exists a high degree of immiscibility between uranium and another metal that might be used as an extractant in such a processing scheme.' Two of these systems in which a high degree of immiscibility exists are those of uranium with the two rare-earth metals, lanthanum, and cerium. Since the rare earths constitute a significant fraction of the fission products, their removal is of prime importance. It is reasonable to believe that this might be accomplished by equilibrating a rare-earth phase with the contaminated uranium fuel in the liquid state. In order to make a more complete study of those systems which would be of interest either as extractants in a liquid-liquid extraction process, or as fission products formed in the fuel, the alloy systems of uranium with lanthanum, cerium, praseodymium, neodymium, and samarium were studied in some detail in the temperature range 1000" to 1250°C; less detailed studies were made with the other rare earths. In addition to being of value to the reactor program, the data obtained in this study should be of help in making a study of the role played by the electronic structures of metals in determining the nature of metallic solutions. The unique electronic structures of the rare-earth elements make them particularly interesting in this respect. EXPERIMENTAL The usual procedure for a solubility determination was to seal equal volumes of uranium and the particular rare earth in a tantalum crucible under an atmosphere of helium; this crucible was then sealed in a stainless steel jacket in an atmosphere of helium. These samples were equilibrated by repeated inverting of the crucibles in a furnace for 15 min at the desired temperature, left in an upright position for 15 min to permit separation of the two phases, and then quenched under a stream of water. In some runs the temperature of the furnace was held 50' to 100°C above the desired quenching temperature while inverting in order to insure good mixing. However, it was found that above 1200°C the crucibles were subject to failure and for these runs the furnace temperature was not raised above the desired quenching temperature. A small amount of tantalum was dissolved in the uranium and the rare earths in these runs, a maximum of 3 wt pct in the uranium phase at 1250°C and up to 1 wt pct in the rare-earth phase at this temperature. On cooling, the major portion of this tantalum precipitated as primary tantalum crystals. Any residual tantalum would probably have a negligible effect on the mutual solubility of uranium and the rare earths in each other. Samples for analysis were cut from each phase with an abrasive cutting wheel; the region near the interface between the two metals was carefully avoided. In the case of the rare earths with melting points above 1250°C no solubility data were taken on the rare-earth phase since this phase could not have achieved equilibrium in a reasonable length of time. (For the same reason no data were taken on the uranium phase below its melting point of 1132°C.) Equilibrium appeared to have been reached in the uranium phase in these cases although the rare-earth phase had not melted. To verify this, samples were melted together in an arc furnace similar to that described by Kroll.2 These samples were sub-

Jan 1, 1960

By Charles Austin

IN an earlier series of studies on 18-8 stainless steel at 600°, 700°, and 800°C.1 one pretreatment was used throughout; viz., 15 min. in hydrogen at 950°C., followed by an air quench. Several manufacturers of this alloy since have expressed doubt as to the suitability of the temperature employed, recommending instead the more customary Strauss treatment as promising superior results. In this subsequent investigation on the effects of the temperature of pretreatment several interesting points have arisen, which are described in this paper. Previous work on our equipment had shown a marked difference between alloys of "similar chemical composition" that had been manu-factured by different companies. Accordingly, one mill-bar length was selected from which to prepare all specimens. It could then be assumed that any marked differences in creep characteristics would be due to effects resulting from variations in the pretreatment of the alloy. The material was furnished by the Allegheny-Ludlum Steel Co. in the form of 5/16-in, dia. rod, finished by air cooling from a mill anneal at 1950°F. (1066°C.). It was analyzed only for the elements shown: carbon, 0,07 per cent; chromium, 18.73; nickel, 9.46; manganese, 0.40. Three pretreating temperatures were chosen, the specimens being held for 15 min. in hydrogen at either: (1) 1150°C., to conform to the recom-mended Strauss treatment; (2) 950°C., to compare with the results of previous tests; or (3) 750°C., to initiate precipitation of carbides in the material before testing. As the test cross sections were only 1/8 -in. dia., air cooling followed the annealing treatment. These treatments per-mitted two direct comparisons: (1) between the 1150° and 950°C. treat-ments to indicate the effect of grain size when all carbides were probably in solution at the start of the test; and (2) between the 950° and 750°C. treatments to indicate the effect of carbide "nucleation" for similar grain sizes.

Jan 1, 1940

The new, internationally-owned Savage River Mines iron ore mining, concentrating and pelletizing project, built and operated by Pickands Mather & Co. International, was dedicated March 6 at Port Latta, Tasmania, Australia. Construction of the $79 million project began in 1965 and involved an open pit mine and concentrating plant plus a complete town for about 350 employees at Savage River; a 53-mile pipeline to transport the concentrates; a pelletizing plant and shipping facilities at Port Latta, which is on Bass Strait separating Tasmania from the Australian mainland. The project has a rated capacity of 2.25 million Ltpy of high-grade magnetite pellets, which will be sold to five Japanese steel companies under 20-year contracts. The open pit mine is located in the central portion of the Savage River deposits. Mining equipment, capable of moving 10 million tpy of ore and overburden, consists of four 6-cu yd electric shovels and 12 50-ton trucks. The concentrating plant, with a design capacity of 5 million tpy of ore, will use magnetic separators to upgrade the ore, which averages 38% iron, to a concentrate averaging 67% iron.

Jan 4, 1968

By Franklin J. Stermole

L. Alan Weakly, member SME, is a senior staff engineer, Exxon Co. Weakly chaired a Mining Engineering committee formed to solicit materials for six planned "personal skills" articles, to be used in ME this year. What follows are Weakly's introductory comments to the series. Upon graduation from college several years ago, I thought that I was sufficiently prepared to embark in my chosen profession. A short time later I realized that several years of on-the-job training was going to be required before I could use my technical training effectively. It never occurred to me that, professionally, I was seriously lacking in any other skills. My spelling could use a little upgrading, but this was not a serious deficiency. I have been very fortunate to have had two employers that recognized that their engineering professionals did lack other skills and made every effort to give them training to correct these deficiencies. The skills I am referring to are those in administration and interpersonal relationships. Most mining engineers and geologists receive very little, if any, college training in these areas. In addition, many companies do not provide this training and many mining engineers and geologists are unaware of their deficiencies. It is for this reason the subject of personal skills development is being introduced in Mining Engineering. The mining engineer or geologist can pursue one of two basic career directions, managerial or technical. In today's technically sophisticated society and highly competitive business climate, both orientations require administrative and interpersonal skills. Most of us are technically qualified and we continue to upgrade our technical skills. But many studies indicate that we, as a group, are significantly weaker in administrative and interpersonal skills than other professional groups. In addition, these studies indicate that engineers, in general, take longer to reach managerial levels and fewer do so. This series in Mining Engineering, then, should help readers strengthen and broaden their professional capabilities. In all industries, including mining and petroleum, economic analysis of potential investment projects is done to select the projects that will give maximum future value from the investment of available capital. Rather than looking directly at the future values to be generated by investing capital in alternate ways for economic decisions, evaluators usually use either rate of return, present value, annual value, a profit to investment ratio, or various break even analysis results to reach economic analysis decisions in evaluating alternative investments. Alternative economic evaluation techniques are used in industry to properly analyze the economic potential of various investment projects. "Discounted Cash Flow" analysis is the phrase commonly used to describe these techniques. Whether you want to analyze projects in mineral, petroleum, real estate, refining, pipe-line transportation, or any other industry, proper application of discounted cash flow analysis techniques enables you to fairly compare the economic potential of alternative projects as well or better than you can using any other project evaluation approaches. It should be pointed out that investment analysis generally involves more than economic analysis. Financial and intangible considerations sometimes are as important or more important to investment decision-making than economic considerations. Economic analysis refers to evaluation of the profit generating potential of projects, that is selecting which alternative projects will generate maximum future value possible from available investment capital. Financial analysis, on the other hand, relates to analysis of where money is going to come from to finance various projects. Regardless of the economic potential of a project, if financial analysis indicates that we cannot finance the project, it likely will be shelved for financial reasons even though it may be economically satisfactory. Many evaluators use the terms "economic analysis" and "financial analysis" interchangeably, but this author considers that to be undesirable. Intangible analysis relates to project factors that are difficult to quantify in

Jan 2, 1984

By J. P. Downey, L. G. Twidwell

"The high density sludge process (HDS) is a commercially proven acid rock drainage wastewater treatment process that is based on acid neutralization and metal precipitation. Previous studies have established that metal removal efficiencies in precipitation-based wastewater treatment applications can be improved through metal ion adsorption on ferrihydrite and/or aluminummodified ferrihydrite. This study was conducted specifically to determine whether the metals removal efficiencies at an existing industrial facility could be improved by promoting ferrihydrite and/or aluminum-modified ferrihydrite precipitation during the pH adjustment stages of the HDS process. The metal tenors of the treated wastewater samples are compared with those obtained through baseline experiments, which were designed to simulate the conventional HDS operation. The subject metals were: aluminum, arsenic, cadmium, copper, iron, manganese, nickel, and zinc.IntroductionThe HDS process is commercially proven ARD wastewater treatment technology that involves raising the wastewater pH by adding hydrated lime, caustic soda, or another alkaline substance. In addition to neutralizing the acidity, many dissolved metals precipitate as pH is elevated. Waste volume is minimized by capturing and immobilizing the precipitated solids.However, ARD streams characteristically contain multiple dissolved metal species. The response of various metals to pH adjustment in the HDS process is neither uniform nor quantitative, so minor to trace concentrations typically remain in the treated wastewater following solid-liquid separation. The effectiveness and applicability of the process would be improved if a means were found to further reduce the metal concentrations.Previous research and industrial applications have proven that metal ion adsorption on ferrihydrite (FH) and/or aluminum-modified ferrihydrite (AMF) increase metal removal efficiencies. Ferrihydrite and AMF are considered ideal for cation and anion adsorption from an aqueous solution at the appropriate pH [1]. Ferrihydrate adsorption of dissolved heavy metals is widely practiced throughout the world [2, 3]. It is established that FH and AMF effectively adsorb As contained in aqueous solutions [4]. Arsenic removal by adsorption on FH is the U.S. Environmental Protection Agency’s (EPA) Best Demonstrated Available Technology [5]. Twidwell and Leonhard also demonstrated that heavy metals (Cd, Cu, Ni, and Zn) are effectively removed from solution by coprecipitation/adsorption using AMF and FH [6]."

Jan 1, 2008

By E. Yalçin

The data set often contains one or more secondary variables. These secondary variables are usually spatially cross correlated with the primary variable. The addition of the cross-correlated information reduces the variance of the estimation error by using the cokriging method. The grade estimation results of ordinary kriging and cokriging methods are evaluated and it was found that the estimation variance of cokriging method is slightly lower than ordinary kriging. The effect of variation of block dimension on the estimation results is also investigated and it was seen that the cokriging estimation variance values also decrease as the block dimension increases.

Jan 1, 2005

By William G. Pariseau

Solvay Chemicals Company mines trona in south-central Wyoming and has done so for many years. The mine is one of several in a mid-continent sedimentary basin that hosts the largest trona resource in the world. Trona is an evaporite, a sesquicarbonate that occurs in several seams of varying thicknesses and depths. Trona is processed into soda ash which has a number of industrial uses in the manufacture of glass, detergent, paper and chemicals. Figure 1 shows the location of the Solvay Mine. A ventilation shaft was recently excavated at Solvay Chemical Company’s mine in the trona patch. In fact, a 22 ft (6.7 m) diameter shaft (inside diameter) was bored upwards from the 1500 ft (457 m) level to the surface. The first bored section was 26 ft (7.9 m) in diameter that allowed for a 2 ft (0.6 m) thick concrete liner. This section began at a depth of approximately 1500 ft (457 m). A second bored section was 24 ft, (7.3 m) in diameter that allowed for a 1 ft (0.3 m) thick concrete liner. This section began at a depth of approximately 750 ft (229 m). This shaft is the #5 Shaft. Figure 2 shows the cutter head used to excavate the shaft.

Feb 1, 2025

By J. A. Lamonica

The Bureau of Mines studied two types of approved coal mine dust personal samplers to determine the effect of decreasing the amplitude of airflow velocity fluctuations on cyclone performance. Results indicate that more dust is collected when pulsation free flow is used. Velocity fluctuations were reduced by means of a pulsation damper; damper efficiency of about 85 percent was needed to reduce the fluctuations to an acceptable level. The data were obtained employing both pulsating and non-pulsating flow. A comparison was made of (1) the masses of respirable coal dust as determined by weighing and of (2) the particle size distributions as determined by an electronic counter. An empirical relationship is given between the ratio of masses collected using pulsating and nonpulsating flow (M') and the ratio of the maximum air velocity to the minimum air velocity (V') as measured in the cyclone entrance channel.

Jan 1, 1972

By E. W. Pehrson, J. W. Furness

THE five charts presented here- with are part of an original group prepared by the U. S. Bureau of Mines showing the international trade in the principal metals and metallic ores. Charts 011 anti- mony, chromite, copper, lead, manganese, mercury, nickel, tin, tungsten, and zinc were published in the February, 1936, issue of the Engineering and Mining Journal. Those shown here include bauxite, aluminum, iron ore, pig iron, and the platinum-group metals.

Jan 1, 1936

By A. T. Iannacchione

Recent fatal injuries occurring during pillar retreat coal mining call for better identification of the hazards and recognition of risks. Ground control hazards associated with room-and-pillar retreat mining tend to intensify with depth, requiring extra precautions in the form of additional controls. In many locations these activities are further complicated by local complexities often associated with unique or novel circumstances, such as over-mining or under-mining. One technique recently studied by NIOSH, Major Hazard Risk Assessment (MHRA), may help mine operators to mitigate the risks associated with pillar recovery operations. The approach was trialed at two underground coal mines in southern West Virginia that are currently practicing pillar recovery. The first step in the MHRA process involved reviewing the segments or parts of the pillar extraction mining system and identifying associated hazards and threats to the operation. Some of the high risk hazards at these two sites included: ? Rock fall during pillar extraction covers equipment and injury occurs during recovery operations, ? Rock fall above the roof bolt horizon, potentially injuring ? workers and/or requiring recovery action, ? Rib fall under deep cover, potentially injuring workers, and; ? Strata instabilities associated with subsidence of the interburden due to simultaneously mining two seams in close vertical proximity to one another. The mines? risk assessment teams then considered each threat individually in order to systematically identify potential unwanted events. The top unwanted events were examined individually using structured risk analysis tools. The output from the process includes a list of priority existing controls for monitoring and auditing, and a second list of potential new controls. These controls consisted of: Examples of best practices, ? Enhanced communication, ? Implementing standard operating procedures (SOP), ? Protocols for emergency response actions, ? Effective layouts, ? Efficient monitoring, and; ? Successful audits. This paper documents the process as it unfolded at the two mines, and analyzes the strengths and weaknesses of the MHRA technique as it applies to pillar recovery operations. This work was part of a larger NIOSH research project. NIOSH was responsible for: 1) facilitating the risk assessment process known as Major Hazard Risk Assessment (MHRA), 2) documenting the risk assessment process, and 3) providing mine management with a written draft summary of the risk assessment process. The results of the risk assessment represent the thoughts and opinions of the individual risk assessment teams and should in no way be construed as an endorsement of the risk assessment output by NIOSH or the University of Pittsburgh.

Jan 1, 2009

By Shunli Z, Jin X, Guanzhou Q

Flotation behaviour can be controlled, due to diminishment of granula quality and extension of specific surface area, by adding coarse particles (high- grade concentrates) to condition pulp. It has been substantiated that coarse particles can intensify fine particle flotation and its mechanisms are effects of carrier, intermedium and assistant aggregation of coarse particles. Calculation and analysis of Reynolds numbers and their variation for different size particles, under specific turbulent dynamic conditions, reveal that agglomeration among granulae is subject to specific turbulent dynamic conditions. Furthermore, sizes and adhesion strength of flocculated particles are the function of specific physical and chemical factors. Based on this research an innovative ramification carrier flotation process has been developed, which has been applied to Fankou Lead- Zinc Mine, Guang Dong province, China, etc, with satisfactory results. These results shed light on distinction between conventional flotation and fine particle flotation, meanwhile, provide a basic approach for further solution of fine particle flotation problem.

Jan 1, 1993

By Zhanjun Wang, Yongqi Sun, Mei Zhang, Zuotai Zhang, Min Guo

The role of fluorine on the viscous and crystallization behavior of CaO-SiO2-MgO-Al2O3-FetO-P2O5-(CaF2) slags were explored using the rotating cylinder method, non-isothermal differential scanning calorimeter (DSC), X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. It was found that the viscosity slightly decreased with increasing CaF2 content. It was also found that CaF2 addition can promote the primary phase transformed from MgFe2O4 spinel to Ca3(PO4)F, which was beneficial to the enrichment of phosphorus. Additionally, the structure of the slags explained by X-ray photoelectron spectroscopy (XPS) and magic angular spinning nuclear magnetic resonance (MAS-NMR) were further analyzed, which was well in accordance with the above analysis.

Jan 1, 2016

By Xianxin Shi

In surface electrical exploration the high resolution earth resistivity method (HRRM) is a very effective method for detecting abandoned drift mines workings. When the abandoned mines are more than 500 ft (150 m) deep, its detection capability reduces greatly and requires more effort to implement. In Yan Quan coal mine, Shanxi province, we tried to adapt this method for underground application. Two survey lines were designed with the spacing of current and potential poles 20 m and 10 m, respectively and measuring points at 2m. The measurement radius of I line and I1 line were 140 m and 60 m, respectively, and the infinitely far pole was 1200~2000 m from the survey line. (Note the I and II lines are located on the north and south ribs of main tunnel, respectively). The survey results showed that abandoned workings were located at 25-70m, Survey Line I and at 80-1 10m, Survey line 11. Based on this finding, the longwall panel gateroads and set up entry were properly located thereby providing safe mining of the No. 15 Coal seam. Key Words: Abandoned coal mine, High resolution earth resistivity, Underground electrical exploration

Jan 1, 2005