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By J. I. Paige

The effect of fluoride inclusions on the properties of titanium produced from the Bureau of Mines-developed induction slag melting process is of concern to the titanium industry. The objective of the research was to determine the effect of removing the nonconductive molten calcium fluoride (CaF2) slag used as an insulator between the titanium and the segmented copper crucible. The data were obtained from single-induction-melted ingots prepared with no CaF2 insulating slag and an ingot prepared with the normal addition of 4 pct CaP2 slag. The results showed that the mechanical properties of single-induction-slag-melted and annealed Ti-6AI-4V alloy exceed the minimum values specified in "Aerospace Materials Specification for Titanium Alloy Bars and Forgings AMS4928H." High-cycle, tension-tension fatigue testing yielded similar results. The data from 44 of the 45 specimens were contained within the typical scatter band for fatigue data on wrought Ti-6AI-4V alloy. Although the removal of the insulating slag is a desirable change, the data from the specimens with the previously standard 4 pct slag addition showed no detrimental effect from the slag inclusions.

Jan 1, 1988

By Jianmin Qin, Raja V. Ramani, Wilson Miola

"The number of underground work entities operating under reduced dust standards in U.S. coal mines has been increasing since the start of the decade of the 80s and is currently approaching 10,000. The concern for controlling the quartz levels in airborne respirable dust in coal mine has manifested itself in several improvements in equipment selection and operation, face ventilation practices, and dust control procedures. At the same time, fundamental studies have been initiated on determining the source-sink relationships of the airborne quartz dust. The P-7 method is the prescribed method for the determination of quartz in the respirable airborne dust samples from coal mines. Questions have been raised on the reliability of the P-7 infrared spectrometry method for quartz analysis in powders. No specific method has been defined for quartz determination in bulk samples from the mine.In a recent study on the relationship between quartz in the airborne dust and that in the materials being mined, both infrared (IR) and x-ray diffraction (XRD) methods were used on a suite of samples from several coal mines. These samples encompassed airborne respirable dust samples, airborne total dust samples, the oversize fraction from the respirable samplers, ROM samples, channel samples, and chip samples from the face, roof, and floor materials. In this paper, the sample preparation and analysis procedures for the samples are discussed. The data, analysis results, and comparisons of the P-7 and XRD results are presented. The quartz percent determined for the same sample by the two methods are different. In 85% of the samples analyzed, the quartz percents determined by the XRD method are higher than those obtained by the P-7 method. However, there is a strong linear relationship between the results from the two methods. Further, the XRD method indicates an average of 20 percent more quartz than that from the P-7 method. The reasons for the differences in the results and the need for additional studies are explored.Since the enactment of the Federal Coal Mine Health and Safety Act of 1969 and the Federal Occupational Safety and Health Act of 1970, the prevalence of free silica as an occupational hazard in dusty work environments has been a matter of increasing concern. In underground coal mining, sometimes, roof, floor, clay veins and other non-coaly material must also be mined along with the coal. Mining these materials may increase the amount of quartz in the airborne dust (Pimentel and Adam, 1985; Taylor et al., 1984; Colinet et al., 1985). The problem of high quartz levels in the respirable airborne dust is widespread in continuous miner sections. In addition to the need for controlling the silica amount in mine atmosphere, a need for a sensitive, easily performed method for the determination of free silica in airborne dust samples was also recognized."

Mar 1, 1992

By Yihan Liu, Jintao Zhang, Chen Xiao, Xiaomeng Zhao, Guanglei Song

To estimate the performance of the inert anode materials based on NiFe2O4 spinel ceramic during it used for aluminum electrolysis, we investigated the wetting process of cryolite molten salt which is in composition of industrial aluminum electrolysis with carbon anode and NiFe2O4 based cermet materials, by means of determination the interface wetting angle between the molten cryolite electrolyte and the solid anodes interface. The results show that the wetting angle between the electrolyte and carbon anode is larger than 90 angulation, this means that they basically can not wetting; however the nickel ferrate spinel ceramics behaves much better. In regard to the NiFe2O4 matrix materials, their initial wetting angles is 76.9. The initial wetting angles for 1.0wt%MnO2, 2.5wt%TiO2 and 0.5wt%V2O5-doped samples are respectively 56.86°, 52.98° and 51.93°. However, after 50s later, all the wetting angles came down below 15°.

Jan 1, 2015

By Robert P. Bruno

This report covers the study of the feasibility of using a hand-held infrared viewer as a methane indicator to observe methane gas at the face of an underground coal mine. The objective of this program was the development of a hand-held device to remotely detect the presence of concentrations of methane gas in underground coal mines. Convenient "mapping" of methane from a remote location would allow rapid and safe corrective procedures for working personnel. Modified commercially available equipment was evaluated both in the laboratory and in a working mine. Although readings were obtained and the general principle of operation demonstrated, the power levels necessary, and protective enclosures required, would raise the weight of the instrument beyond practical limits of portability. Based on currently available technology, it is the conclusion of the investigations that a practical, portable, hand-held visual methane indicator is beyond the state-of-the-art. The recommendation was, therefore, made that work be suspended, and the results and data compiled and presented in a final program report.

Jan 1, 1979

By Seth Robertson, Daniel Belardo, Travis Coleman

Thermal Integrity Profiling (TIP) is a non-destructive method used to evaluate drilled deep foundation integrity. This integrity testing method is specified more frequently, and is becoming an industry standard in the transportation and private construction sectors. This testing method utilizes heat generated during the concrete/grout curing process to assess deep foundation integrity over the evaluated length. With compilation of the measured temperature versus time and installation records, a model of the Effective Average Radius versus measurement depth is generated. The generated effective shaft model is highly dependent on specific construction details, subjective modeling parameters, and proper interpretation of concrete/soil heat dissipation characteristics. Key components of the TIP analysis include both qualitative and quantitative assessments. Qualitatively, variations or sharp reductions in temperature profiles may indicate potential anomalous regions. Quantitatively, a correlation is established between measured temperatures and estimated Effective Radii for subsequent integrity evaluation. Best practices in processing the TIP measurements are presented, including selecting the optimal time for analysis, normalizing the thermal profile, and proper interpretation of potential anomalous regions. Recommendations for implementing mitigation efforts and interpretation of the TIP results are presented.

Sep 8, 2021

By A. W. de Villiers

This paper explores the behaviour of methane in the goaf during longwall mining, together with some methods for the control of methane emissions into the goaf, the working face, and the ventilation system. Experimental work done at Twistdraai Colliery, Sasol Coal, is referred to, as well as the gas-drainage system being practised at West Cliff Colliery in New South Wales, Australia. Gas drainage is discussed briefly, and certain suggestions are made in regard to coal mining in South Africa.

Jan 1, 1989

Charles H. White, Harvard University, Cambridge, Mass, (communication to the Secretary*):—In answer to Mr. Jar-man's questions I am able to say that constant use (during term-time) since 1901 has shown the new appliances in our laboratory to be very satisfactory. The draft in the hoods is sufficient to lift the fumes promptly from the baths and hotplates ; and the occasional application of stove-polish,—usually about three times a year, at the recess-periods,—so well protects all iron-work in the hoods that, up to the present time, there is very little evidence of the corroding action of acid fumes. Iron should never be used in the construction of hoods above

Jan 1, 1906

By Tobin GJ

Testwork carried out in the cooling water circuit at the Yabulu treatment plant of the Greenvale Joint Venturers (Metals Exploration Queensland Pty. Ltd. and Freeport Queensland Nickel Incorporated) since 1980 has resulted in significant improvements to both fouling and corrosion control. At the same time corrosion inhibitor costs have been reduced.Acrylate-type silt dispersants were identified as the most effective means of sediment control in the circuit. An increase in the cathodic component of the corrosion inhibitor coupled with a relatively minor adjustment to water pH has yielded a two to three fold reduction in corrosion rate. It has been established that these lower corrosion rates can be sustained in the face of a 20% reduction in corrosion inhibitor addition rate. Further improvements are indicated with a change of raw water algicide.

Jan 1, 1985

By E. M. Tignor

As a part of the program of promoting the conservation and efficient utilization of petroleum, studies are being made by engineers of the Bureau of Mines on secondary oil-recovery projects throughout the United States. In furthering that aim, engineering data concerning the reservoirs, methods of stimulating the production of oil, and other pertinent facts are collected, studied, and subsequently published so that others may profit by the experience gained. This report presents the results of a study made by engineers of the Franklin, Pa., office of the Bureau of Mines of secondary oil-recovery operations in the Boggs field, Spencer district, Roane County, W. Va., whore natural gas is injected into the reservoir to stimulate the production of oil from a so-called stripper field. The Boggs field, like most others in the Appalachian region, is one in which the major part of the natural energy that caused oil to flow through the reservoir to the producing wells during the primary stage of oil production has been dissipated. For all practical purposes, most of the oil produced in the Appalachian region at the present time can be considered to be from stripper fields. Consequently, secondary recovery methods are being used extensively in the oil-producing areas of New York, Pennsylvania, West Virginia, Ohio, and Kentucky for recovering some of the oil that was not produced by primary production methods.

Jan 1, 1949

By Donald G. Wieland, James H. Meinholz

INTRODUCTION The Milwaukee, Wisconsin Metropolitan Area provides an ideal opportunity to review the advancement of the art and science of mixed face tunneling in the past 65 years. Although there were earlier tunnel projects in the Milwaukee area, by other agencies, the majority of those driven in the Twentieth Century have been done under contract with the Milwaukee Metropolitan Sewerage District through the agency of the Sewerage Commission of the City of Milwaukee and the Metropolitan Sewerage Commission of the County of Milwaukee. Legal Description of District The Milwaukee Metropolitan Sewerage District was created by the Wisconsin Legislature in 1921 together with the Metropolitan Sewerage Commission of the County of Milwaukee. This concept of subregional wastewater control was an outgrowth of an investigation and report from a commission appointed by the Common Council of the City of Milwaukee in 1909 to study final sewage disposal for the City. In 1911 that Commission, comprised of J. W. Alvord, George C. Whipple and Harrison P. Eddy, recommended that the City construct a water filtration plant, construct a Menomonee River flushing works, expand the intercepting sewer system and, after a thorough study of the then existing and developing methods of sewage treatment, construct a sewage treatment plant. In response to those recommendations, the Wisconsin Legislature, in Chapter 608 of the Laws of 1913, created the Sewerage Commission of the City of Milwaukee. Recognizing that the improvement of surface water quality would require action on a watershed basis, the Legislature, in Chapters 554 and 590. of the Laws of 1921, created the

Jan 1, 1979

By John D. Spencer

Surveys to establish the quantity and quality of coals available for metallurgical, industrial, and energy use, investigations to develop better mining methods, and studies aimed at improving the health and safety of those who mine the coal highlighted Bureau of Mines research and technologic work on coal in 1968. Also being developed are more efficient methods of coal preparation, transportation, storage, and utilization. Supplementing this effort are projects designed to assure minimum disturbance of land, water, and air resources. Research centers and laboratories of the Bureau of Mines are listed in appendix A. Publications released during 1968 are cited with the various projects and in appendix C. Organizations that cooperated in the work in various ways are cited in appendix B.

Jan 1, 1969

By B. A. Hancock

It is not at all surprising that causticized potato and potato derived amylopectin starch solutions performed much better than their parent starches. Some preparation is required to rupture the starch granules to effect the polymeric adsorption and interparticle bridging necessary for selective flocculation. In laboratory work comparing the deslime performance of causticized and autoclave cooked laboratory corn starch solution preparations, it was found that higher deslime weight rejections, with attendant proportionally greater iron unit losses, occurred with the causticized starch. These results may be specific to the ore involved but they do suggest that cooking and causticizing cause different starch granule rup- ture and/or starch breakdown, which have an effect on desliming response. I calculated from the data in the article that the slimes product grades were high - 24.3% and 20.3% Fe when 53.7% and 54.5% Fe concentrate products were obtained, respectively, in Table 4, and 21% Fe with a 62.6% Fe concentrate in Table 5 - using the natural tailings sample, which had a head of 34.3% Fe. It may be advisable for the authors to consider different starch preparations in future investigations. The combination of upgrading and selectivity results presented in Table 4 are not as good as the authors suggest. The authors' claim that a system has been developed to produce saleable concentrates from the Kudremukh tailings is quite disconcerting. There are many hurdles yet to be crossed before commercial application of selective flocculation becomes possible because differ- ences between the very small-scale laboratory tests conducted and commercial application are rather large. Among the many differences are varying circuit feed grades that will occur from use of tailings, the apparent face that much lower tailings grades will be encountered in practice (it is much easier to achieve a high concentrate grade with reasonable recoveries using 34.3% Fe tailings as in the study rather than 25.3% Fe tailings grades that the plant apparently averages), the hydraulic nature of the thickeners used in operations compared to the static system used in laboratory tests, the different size distributions that will be obtained from a plant closed grinding- classification circuit, and differences in water used in a plant operation and the laboratory. The authors wrote that it was necessary to overgrind to be sure that the coarse gangue would not settle with the iron oxide floccules. This situation is likely to be exaggerated in commercial operations where it is assumed cyclones would be used for classification. Because cyclone classification is greatly influenced by particle densities, there will probably be an even greater difference in size between the iron and gangue particles in the plant, which would make the gangue slightly coarser still in relation to the iron. This would make the selective flocculation-desliming separations using the procedure employed by the authors even more difficult and, using the dispersant system the authors employed, greater overgrinding would be required. To grind finer to minimize the coarse gangue in the flocculated iron oxides is quite inefficient and appears not to broach the problem. The actual problem appears to be insufficient dispersion of the ground pulp. In this situation, addition of a dispersant would likely be required to attain a sufficiently high pulp dispersion level to efficiently effect a selective flocculation-desliming separation. Although the very coarse particles would still have a tendency to settle with the floccules, it probably would be found unnecessary to overgrind as much as indicated. Use of an optimum combination of dispersant and pH modifying reagents may also significantly improve the selectivity of desliming. Additionally, although it is possible that sufficient dispersion may be obtained by pH control alone in some situations, it is quite probable that added dispersity was obtained in the reported work from using distilled water. It is research experience that distilled water enhances dispersion. In commercial operations it may not be expected that sufficient dispersion will be obtained by pH control alone, unless the water used in the process is by nature quite dispersive. Overall, a change in the Kudremukh tailings dispersant scheme appears necessary where a dispersant is used in conjunction with a pH modifying reagent. With this change, different dispersion-flocculation responses will result that would have to be further evaluated. Therefore, it is still an open question whether an efficient and effective selective floccula- tion separation using Kudremukh tailings may be obtained that will produce saleable concentrates.

Jan 1, 1987

By D. Grosse

At the beginning of the 1960's, the Hannoversche Portland-Cementfabrik A. G. needed to open a new quarry. The land on which this quarry was to be developed was completely flat and separated from the existing quarry by a navigable canal. The area had been exploration-drilled previously, so that enough reliable data on the chemical properties of the deposit were available. From the geologic point of view, the deposit under a very moist surface belongs to the Turon (Upper Chalk) formation, soft on the surface and medium to very hard farther down. Between the 15% sloping banks of chalk (with a calcium carbonate content of 75 to 90% and running from west to east), there are numerous beds, up to 3 m deep, which are rich in alumina and iron oxide but contain only 50 to 60% CaCO3. In the old quarry-worked conventionally by deep-hole drilling, a 2-cu-m shovel, and 900-mm track with 6-cu-m dump cars-an adequate and modern crushing plant was available. The plant crushed the moist material (11 to 13% H2O content) down to 0 to 50 mm. INSTALLATION OF ORIGINAL MOBILE CRUSHER It was decided to employ a mobile crushing unit in the new quarry; the moist and soft ground did not permit the use of heavy trucks for transporting the material, and a road network would have entailed a large investment. The use of a rail system was eliminated from the beginning, since the ground would be very uneven after the quarry was developed. At that time only one prototype of a crawler-mounted mobile crushing unit existed. This unit was operating in a nearby works as a primary crusher. A similar, slightly improved machine (Fig. 1) was purchased

Jan 1, 1969

The problem of thin and very thin coal seam extraction in a long perspective of Ukraine?s fuel and energy industry development was determined. Technical and economic benefits of coal seams selective mining technique including beneficial environmental impact were substantiated. The scientific and practical aspects of development of borehole underground coal gasification (BUCG) technology are considered. The technological scheme of underground gas generators is offered on the basis of the authors? criteria of fitness and adaptability to the mine and geological conditions. These charts foresee the preparation of gas generators from earth surface and directly from the present mine working by inclined horizontal boreholes. Basic research is directed at abandoned supplies extraction in coal mines. Concepts of technological decisions and technical implementation of the underground part of the gasification system are worked out with analytical models, with subsequent test verification on special options and a mine experimental gas generator. Forming the technological scheme of gasification is founded on the basis of tying up spatial and sentinel factosr of coal seam gasification taking into account sufficient impermeability of the system a «gas generator ? rock massif» and to dirigibility by thermochemical processes that flow in a rock massif. The offered solutions contain the possibility of creation of the power and chemical enterprises of gasification, taking into account the complex use of BUCG products in the ecologically reserved technological cycle. Gas generator efficiency is evaluated from an economic standpoint.

Aug 1, 2013

By Drain P, Dibdin T. R

THE completion of the Linda incline man and supply haft at the Mount Morgan Gold Mining Oompany's mine led to an investigation of the various safety gears in general use in mining shafts. One of these gears completely fulfilled the necessaryconditions. This paper endeavours to give a description of the man car and safety gears now operating in the before mentioned shaft, together with the main considerations leading to their design and sub equent adoption. Fig 1 diagramatically shows a longitudinal section of this shaft.

Jan 1, 1911

By Gordon Kidd

Inflation and burgeoning costs are two among many factors which have generated a new surge of interest in "fringe benefits" (sometimes referred to as "supplementary remuneration" or "supplementary compensation"). Other specialized forms of compensation ("perks", in the vernacular) such as company cars, windowed offices, etc., which also are the subjects of current study, are outside the scope of this paper. For businesses, interest in fringe benefits is based on concern for employees? welfare, compliance with government requirements, and an increasingly burdensome impact on bottom lines. In 1980, according to Fred D. Lindsey in the October 1980 issue of Nation's Business, employee benefits will cost American employers an estimated $420 billion. To paraphrase Winston Churchill, "some fringes!" Indeed, few if any administrators consider employee benefits as fringes. Employee benefits impact other major areas of a company's operations as well. As listed by Beadle (1980), these areas include employee relations, collective bargaining, short-term costs, long-range funding, manpower planning, compliance with legislation, taxation for the company and for the employee, corporate image in the community, competitiveness for staff, communications, administration, claims cost containment, etc., etc.

Jan 1, 1980

By Johan Sundström

Anhydrous DyC13 was prepared by dehydration of DyCl3?6H20 in a fluidized bed using both batch- wise and continuous feeding. A gas mixture with varied composition of argon and HCl was used. The productivity was high, reaching values of 0.25 mol H20/m2-st during the reaction step 6- 1 and 0.062 mol H2O/m2.s during the reaction step 1-0. The product was free from hydrolytic compounds, such as DyOCI, if control of inlet gas composition versus temperature was achieved. From the results of various experiments, some relations between HCI-concentration and temperature in order to avoid hydrolysis have been deduced. The fluidization process efficiency decreases drastically after the dehydration has proceeded down to about 10 mol% of remaining water. Therefore, in a final treatment the last traces of water were removed by slowly purging gas through a packed bed. The water content could thereby be reduced to less than 1 mol%.

Jan 1, 1997

By Denholm WT

The main objective of the experimental study was to investigate the dissolution kinetics of various forms of carbon under iron bath converting or smelting-reduction conditions, i.e., particulate, free moving carbon in contact with a turbulent iron melt. Iron/carbon melts were contained in cast magnesia-lined silicon carbide crucibles heated by a medium frequency induction furnace. The melts were stirred by injecting nitrogen through 2 mm I.D. alumina lances submerged to a depth of 50 mm in the 100 mm deep baths. Particulate carbon in the form of graphite, brown coal char and petroleum coke, were dropped directly onto the turbulent bath. The dissolution rates of the various carbon types were monitored by taking periodic bath samples for subsequent carbon analyses. The effect of carbon particle size (1-6.25 mm), the degree of bath turbulence (nitrogen stirring rates of 0-20 litres/min), and bath temperature (1300-1500¦C) were assessed. The analysis of the results was complicated by particle buoyancy effects, but it was established that the dissolution rates of the three carbon types investigated were similar, and increased linearly with increases in the gas stirring power inputs. Particle size had relatively little effect on the dissolution rates.

Jan 1, 1984

By R. J. Sherman, M. R. Achter

Creep rates have been measured for nickel at 1200°F in air and in vacuum, and related to the depth of surface cracks in the specimens tested in the two environments. The surface cracks were observed to grow faster in air than in vacuum in both short-time and long-time tests. Crack depths, however, could be correlated with creep rates only in the short-time tests. Although no cracks were observed in a relatively brittle Ni-Cr-A1 alloy creep tested at 1300°F, the appearance of alloy specimens fractured after interruption in creep indicated that there was a decrease of intergranular cohesion resulting from the diffusion of atmospheric gases into grain boundaries. PREVIOUS investigations1-3 have demonstrated that the effect of atmosphere on the high-temperature strength of nickel and nickel-base alloys may be reversed by changes in the stress or temperature of the test. At high stress and low temperature the creep-rupture life is longer in vacuum than in air, while at high temperature and low stress the relative strengths are reversed. A mechanism to explain this behavior was proposed based on two competing processes. Oxidation hardens and strengthens a metal, but adsorption of gas, by lowering surface energy, reduces the work required to propagate an intergranular crack. The controlling process is determined by temperature and stress. Basic to this mechanism is the concept that environment determines the ease of propagation of intergranular cracks and thus affects creep rate and rupture life. To explore the mechanism in greater detail, this investigation was undertaken to determine the effect of atmosphere on crack initiation and propagation rates in nickel1 and a relatively brittle Ni-Cr-A1 alloy.3 EXPERIMENTAL PROCEDURE The materials were the same as used previously. Nickel of 99.8 pct purity had the following impurity content: 0.02 pct Co, 0.03 pct Fe, 0.02 pct Mg, 0.03 pct Si, and 0.008 pct C. Rods were cold swaged from 1/2 in. to 3/8 in. in diam and machined into speci- mens with gage sections 1/4 in. in diam by 1-1/4 in. long. They were annealed in vacuum at 1600" F for 1 hr to achieve a grain size of 0.07 mm. The alloy was composed of 19.1 pct Cr, 3.6 pct Al, 1.7 pct Si, 0.57 pct Fe, 0.10 pct Mg, 0.027 pct C, 0.004 pct S, and the balance Ni. Sheet specimens of 0.500-in. width and 1.25-in. gage length were machined from 0.033-in.-thick strip and annealed in vacuum at 2000° F for 2 hr, resulting in a grain size of 0.036 mm. Large amounts of an intergranular phase were introduced as a result of the anneal. Creep tests on both materials, using equipment previously described by Shahinian; were conducted in air and in a vacuum of 1 x 10-5 mm Hg. They were continued to rupture and interrupted at various stages of the test. Although extensions were measured from dial gage readings of movement of the lever arm, it is considered that valid comparisons of creep rate may be made in this manner.l Two parameters were measured metallograph-ically* on longitudinal sections of nickel specimens interrupted during creep—the mean depth of surface cracks 2, and the density n as the number of cracks per unit length of surface. They were combined into one parameter by the relation p = n-d [1] As used here, p is equal to the total of crack depths per unit length of surface. RESULTS Nickel. It is well known that the incidence of intergranular cracking is increased with increasing rupture life. Indeed, it is evident in Tables I and I1

Jan 1, 1962

By J. C. Kerkering, J. C. Franklin, T. O. Meyer, R. W. McKibbin

A continuous survey of radon gas was made in two interconnecting stopes in a southwestern U. S. uranium mine to determine how the various phases of the mining cycle affected the radon concentration. The radon was monitored continuously with five detectors. One detector monitored the intake air, one the exhaust air, and three the stope air. The radon concentrations present during slushing, blasting, and exhaust fan shutoff were compared with concentrations on a nonwork day as a base level. Inside the stope, the radon concentration increased about 40% during slushing and 425% after blasting. Intake air radon increased 1600% and the stope air increased 550% while the surface exhaust fan was off.

Jan 1, 1979