Search Documents

By M. P. Brameld, G. Archambault, R. H. McCorkell

"The rates. J. at which materials emit radon are of interest in studies of the sources of radon in mines. buildings. soils overburden and other places where it may indicate the location of ore or be a health hazard. Here J values were determined by measuring the radon concentrations by means of scintillation counters or alpha-particle track detectors in chambers in which specimens were sealed. Errors in the measurements due to leakage from the chambers. lack of secular equilibrium in the decay series of the radon measured, or the limited rate of diffusion of radon from powders or within the chambers were shown to be insignificant or could be corrected. Scintillation counter measurements are highly reproducible; track detector measurements also appear useable and may be made on many small samples using small, simple chambers. J measurements were made for uranium ores, drill cores, standard CANMET pulps. concrete and gypsum board. Powdering of ores had little effect on their J values.IntroductionIn the mining and mineral sciences, radon (222Rn) is of interest chiefly for two reasons: in geochemical exploration for mineral deposits its presence in soil. overburden and water in more than background concentrations may indicate the existence and locations of uranium deposits and, if present in sufficient concentrations, it is a possible health hazard in mines, mills and other places where people live and work. The latter aspect of radon's role has received considerable attention recently(1,2,3,4,5), and surveys of soil-gas radon concentrations have been used for some time in searches for uranium deposits(6,7,8,9,)."

Jan 1, 1981

By Oliver Smalley

EXCEPT for the work of Guillet, who conducted a systematic investigation on the zinc-replacing value of nickel in brass, and extended his investigation with a view to developing commercial high zinc content nickel brasses, the author does not know of any systematic research on the subject. The most promising commercial alloys and their physical properties obtained by Guillet are given below: Maximum Elonga- Reduction Copper Zinc Nickel Stress, tion, of Area, Brinell Tons Per Per Cent. Per Cent. Sq. In. 55.0 41.0 5.0 24.4 46.5 94 Sand cast. 22.6 27.0 90 Chill cast. 56.7 39.74 3.35 30.0 43.0 51.7 97 Casting annealed 2 hr. at 750° C. 33.9 33.0 50.7 144 Cold-drawn bar. 55.15 42.3 2.24 29.8 33.0 116 Casting annealed 2 hr. at 750° C. 32.3 29.0 151 Cold-drawn bar. These test results scarcely justify the use of such quantities of so expensive a metal, and could have been obtained from ordinary commercial brass. For purposes of comparison, the physical properties of ordinary brasses, ranging from 70 per cent. to 50.1 per cent. Cu in both the cast and normalized1 conditions are included in Table 1. These incidentally furnish a useful standard of the properties of castings and of rolled, extruded and forged brass when correctly annealed. A close study of some of the well-known special brasses containing nickel reveals a series of alloys which bewilder by their complexity, and one can only hazard a guess at the function and commercial value of each of the many elements used.

Jan 10, 1925

By David O. DeGagné

While mine backfill plants are becoming increasingly more automated and instrumented, especially with paste fill operations, underground backfill distribution systems have hardly changed over the years. While fill properties are appropriately measured in the preparation plants, as backfill enters the mine borehole, the technology for control, data gathering and reporting is somewhat lacking. Mines typically experience problems with borehole and pipeline plugging, pipeline bursting, bulkhead failure and exposed fill sloughing. With adequate instrumentation of the backfill system it is possible to obtain a complete, continuous and detailed picture of the entire filling operation from preparation to post-pour. Good data will, over time, provide the basis for needed improvements of backfill systems and will be essential to safer, more efficient and less costly fill practices. This paper will review the areas of the filling operations where monitoring would prove critical to eliminate failures such as pipelines, bulkheads, fill exposures, stope walls, etc. The types of monitoring systems currently available will be reviewed and potential areas for development will be highlighted.

May 1, 2001

By Patrick Pelletier Jr., Pierre-Alexandre Bossé, Gianni Bartolacci, Ian Orford, Steve Parent

"Over the last decades, many authors have shown the importance of froth in the flotation process. Mineral recovery is related to froth recovery and flotation. Selectivity is affected by froth characteristics, especially structure and loading. The characteristics of froth textures could therefore be used for diagnosing flotation.Machine imaging, especially image texture analysis, allows on-line measurement of important froth characteristics and process state classification. The measured characteristics include froth texture, loading and stability indicators. To extract information from images, texture analysis tools are used as well as a block-matching algorithm (BMA). For process state classification, images are analyzed with the same tools and clustering is done with multivariate data analysis algorithms.Two case studies, Brunswick Mine Concentrator Cu/Pb circuit and LaRonde Mine Zn circuit, are presented to show that these indicators may be used for diagnosis and control. The influence of manipulated variables on measured froth features is shown as well as the relationship between froth characteristics, mineral recovery and flotation selectivity.INTRODUCTIONImaging is a way to depict abstract characteristics of a scene or an object; it is often related to other types of scientific observations, chemical component concentrations, for example (Geladi and Grahn, 1996). In this paper, the scene is flotation froth. Imaging can be especially useful in applications where it is difficult to obtain the measurements needed for process analysis – froth flotation, for example."

Jan 1, 2006

By T. A. Sullivan

The processing of sweated aluminum electronic scrap was investigated to develop methods for recovering the aluminum and concentrating the other metals, including copper, lead, gold, and silver, into a product that can be separated by known methods. Two molten-salt electrorefining processes were developed and tested. The first process utilized a three-layer refining cell with a BaCI2-NaF-AIF3 electrolyte, which operated at 750° to 850° C. The second process used an all-chloride electrolyte of NaCI-KCI-AICI3 at 750° to 800° C, with separate anode and cathode compartments. High-quality aluminum was recovered that averaged 99.8-percent pure in the three-layer cell and 99.6-percent pure in the compartment cell. Over 94 percent of the aluminum was recovered with cathode current efficiencies of approximately 90 percent in both methods. The copper, lead, tin, silver, gold, and other metals were concentrated threefold in an anode product. Separation of lead and part of the tin by liquation from this product seemed feasible. The anode product was smelted to prepare a 96-percent copper bullion that contained 690 ounces of silver and 65 ounces of gold per ton, with 98 percent recovery of these values.

Jan 1, 1972

By H. A. Dierks

Implementation of the joint Federal-State control program established in 1955 to cope with the mine water problem in the Pennsylvania anthracite region is described in this report. The increasing severity of the water problem in the anthracite mines has necessitated major adjustments as this continuing program has progressed. Since 1941 the Federal Government has recognized the mine water problem as an important factor in the worsening economic condition of the anthracite region by initiating scientific and technologic investigations and establishing the Anthracite Flood-Prevention Section in the Bureau of Mines in 1948. On the basis of comprehensive investigations and studies, the results of which were published in numerous reports and bulletins, the Anthracite Mine Drainage Commission of the Commonwealth of Pennsylvania formulated a plan that served as a background for legislative action in 1955, resulting in Public Law 162, 84th Congress (Act of July 15, 1955 (69 Stat. 352; 30 U.S.C. 571-576)), for the Federal Government, and Act No. 82 of the General Assembly, July 7, 1955, for the Commonwealth of Pennsylvania. The report covers 29 mine flood control projects approved and executed in implementing the aforementioned legislative acts. Essential engineering and cost details for each project are given, together with an evaluation of the effect that the installed facilities have on alleviating the mine water problem as it concerns individual mines and the anthracite industry as a whole.

Jan 1, 1962

By Michael McVay

The use of augered cast-in-place piles has seen tremendous growth under commerical structures in the past twenty years. Problems with vibration, soil densification and/or heave associated with driven piles do not occur with properly installed augered piles. Augered cast-in-place piles were originally constructed (1950s) with diameters of .31 m (12 in.) and lengths up to 6.1 m (20 ft); however with the advent of better drilling equipment, diameters varying from .41m(16 in.)to .61 m (24 in.) and typical depths ranging from 18.3 m (60 ft) to 24.4 m (80 ft) are achievable. Reinforcement may vary from a single high strength rebar (Grade 60) at the top of the pile to a continuous steel cage depending on loading (compression, tension-uplift, and lateral). Typical axial design loads (compression) for a single augered cast-in-place pile are in the 445 kN (50 tons) to 890 kN (100 tons) range.

Jan 1, 1997

By M. Khandrika, B. K. Parekh

Column flotation has proven to be the most effective technique for the flotation and recovery of ultrafine coal. The commercial application of columns in the coal industry is steadily increasing (Parekh et al., 1990; Yoon et al., 1992). For the flotation of coal or mineral air is used for generating bubbles. Using a conventional flotation cell, Miller and Mishra (1985) compared froth flotation behavior of fine coal using air, nitrogen and carbon dioxide gas. They concluded that carbon dioxide gas provided a higher rate of recovery and a lower ash content. The objective of the present study was to investigate the effect of various gases such as compressed air, nitrogen, argon, and carbon dioxide on the column flotation of fine coal.

Jan 1, 1999

By Y. J. Wang

This paper describes a procedure for solving the generalized system of n network equations in n unknowns considering the following ventilation variables and parameters: (a) air quantities, (b) pressure losses or gains caused by the control devices (i.e., fans or regulators), (c) resistance factors, (d) natural ventilation pressure, and (e) fan pressures (as a function of air quantities). The air quantities and pressure losses for all branches in the network are grouped into dependent and independent variables. The branches with an independent quantity are contained in a chord set, and the branches with a dependent pressure loss are contained in a chord set. In addition to the problem formulation, the solution procedure, applying the Newton method, is discussed and illustrated with a numerical example.

Jan 1, 1989

By John W. Tieman

Research on processes to remove sulfur oxides from flue gas has been in progress for many years. Pioneers in this field were the British who, in the early 1930's, installed a full-scale flue gas scrubbing unit on a 120 MW boiler using alkaline water from a Thames estuary plus chalk. Since that time, various methods have been studied by many investigators. Federal laws covering air pollution started with the 1955 Air Pollution Control Act. With the advent of the Air Quality Act of 1967, and subsequent publishing of criteria and available technology for control of sulfur oxides in January 1969, the clamor for information on commercially available control techniques to remove sulfur from fossil fuels has rapidly increased.

Jan 8, 1972

Improve the accuracy of commonly-used mine air velocity measurement techniques. Approach The Bureau of Mines, through a contract with Ketron, Inc., conducted a detailed study to establish appropriate, generalized correction factors for commonly-used air velocity measurement techniques. The techniques used were centerline readings, continuous traverse and split traverse vane anemometer readings, and smoke cloud readings (see Bureau of Mines Bulletion 589 for details on the proper use of these techniques). The various measurement techniques were used at different mine test sites to measure different air velocities. The data collected from the test sites were used in a statistical analysis which determined a generalized correction factor for each measurement technique. The correction factor multiplied by the measured velocity was used to provide the true velocity.

Jan 1, 1984

By Paul M. Linebarger

This paper is one of a series of digests of foreign mining legislation and court decisions prepared in advance of a general report relative to the rights of American citizens to explore for minerals and to own and operate mines in various foreign countries. This interpretation of the laws of Mexico has been pro oared from the best information available in Washington but is released subject to correction and amplification, if necessary, by the proper American diplomatic and consular officers, to whom it has been referred through the courtesy of the Department of State. INTRODUCTION Present-day Mexican mining legislation involves, not only the latest minim enactment (August 1, 1026), but many other enactments and regulations, principal among which are the Constitution, the Civil Code, the Code of Commerce, the Foreign Law, the Mining Tax Law, and. the Civil Jurisprudence of Mexico--the last-mentioned being based in Dart on Supreme Court decisions. Ere Mexican Federal Government is supreme in mining legislation because, among other reasons, a large part of the revenue of the Government must come from the fiscal control of the mines. All circulars, decrees, and rulings that affect the mines not only have their origin in the Central Government but are administered thereby. The Department of Industry, Commerce, and Labor is in control of all mines. Attention may here be called, however,

Jan 1, 1929

By Henry Rawdon

ANY laboratory corrosion test, as judged from the practical point of view, is valuable only to the extent that it foretells what will, in all probability, occur in service. Such a test is most properly to be considered as a "pilot test, " that is, a test which indicates the direction along which action may be expected to occur rather than as a truly quantitative test which would be expected to tell just how and to what extent the action would proceed. It is generally recognized that laboratory corrosion tests should be chosen with particular reference to the character of service expected for any particular type of metal, so far as it can be foreseen. Even when this requirement has been fulfilled, however, the question whether the actual service behavior of the material is in accordance and general agreement with predictions based upon such laboratory tests is always a pertinent one. The information available in the technical literature bearing on the correlation between the service behavior of metals from the corrosion standpoint, and the results obtained with the same metals in laboratory corrosion tests is very meager, indeed. The results which have been obtained in weather-exposure tests of sheet duralumin which form the body of this discussion are presented here for their bearing on this particular phase of the problem of the corrosion resistance of duralumin. Although the exposure tests described have not been completed, in the sense that all of the tests, in the series initially laid down, have been accomplished, still the general trend shown by the results is so clear that a number of definite conclusions at this stage (subject, of course, to possible modification in the light of later results) are believed to be warranted. The tests reported upon here form one phase of the much broader study of this subject which has been under way for several years in which the National Advisory Committee for Aeronautics, the Bureau of Aeronautics of the Navy Department, the Army Air Corps and the Bureau of Standards have cooperated. Without the very helpful cooperation of the manufacturers in furnishing the

Jan 1, 1929

By L. B. Pankratz

Enthalpies above 298° K were investigated for four crystalline sodium borates by copper-block drop calorimetry. Determinations were made to 1,200° K for NaB02, 1,003° K for Na2B407, 1,005° K for NaB305, and 1,046° K for Na2Be013. No phase transitions or other thermal anomalies were found. The enthalpy determinations, when combined with known heats of formation at 298° K and other supplementary data, enabled the calculation of the heats and free energies of formation of the compounds to their melting points. Values of relative enthalpies, entropies, heat capacities, free energy functions, enthalpies of formation, free energies of formation, and equilibrium constants of formation were tabulated at even temperatures.

Jan 1, 1971

By J. Weng

The equations of heat conduction are numerically solved for two kinds of artificial freezing- mechanical freezing and liquid nitrogen freezing. A two dimensional finite difference model simulating the freezing field is developed. The procedure introduces a way to simulate the effect of latent heat released when water transforms from liquid to solid. The procedure also produces a way to calculate the harmonic mean of heat conductivity used when dealing with heterogeneous material. The theoretically derived temperature distributions in frozen soil are given and compared with measured data. An analysis made on the thermal design in shaft freezing. The average temperature of frozen soil is calculated by using numerical integration. The regularity of development of frozen soil radius is revealed and given in an appropriate mathematical model.

Jan 1, 1984

By C. F. Jr. Nagel

THIS paper is written primarily for those who are familiar with the processes mentioned but who desire a further insight into some of the fundamental principles. It does not give a complete description of the various practices employed in the working of aluminum and its alloys, but presents a few illustrations of the essential respects in which aluminum differs from other common metals, and emphasizes the controlling factors of the processes under consideration. HEAT TREATING Certain aluminum alloys are capable of having their mechanical properties greatly altered by a heat-treatment process. The degree of this improvement may be illustrated by the typical properties of duralumin (Table 1). It is essential that the material be in the wrought condition in order to obtain maximum heat-treatment effects.

Jan 1, 1927

By Kaustubh Joshi, Pradip, Beena Rai, Kesri L. Menaria, Venugopal Tammishetti

"Beneficiation of alumina rich iron ore slimes is a major challenge for the Indian iron ore industry. High alumina is deleterious for the performance of both blast furnace as well as sintering plants. Slimes generally contain 5 - 10% alumina, and hence despite assaying as high as 60% Fe, those are dumped in tailing ponds. The slimes are typically less than 37 microns. Selective flocculation of iron ore slimes using highly selective reagents is thus an option worth exploring. Our research is directed at employing state-of-the-art molecular modeling techniques for the selection/design of selective reagents for this separation. We have earlier reported our results on starch as a selective flocculant for iron ore slimes. In this paper, we present our results on the selective dispersion-flocculation of natural iron ore slimes using guar gum flocculant. With careful selection of various process parameters such as flocculant dosage, dispersant dosage, pH and settling time, we were able to obtain a concentrate assaying >66% Fe and <3.5% Al2O3 with an yield of 65 to 68% (recovery of iron values more than 70%) from a natural iron ore slime sample assaying 58% Fe and 7% Al2O3."

Jan 1, 2014

By Daniel T. Brian, O&apos

Exploration targets and results in the mining industry are commonly summarized in terms of tonnage and grade. Business appraisals require, as additional information, the expected profit or loss implied by the physical summary. The early incorporation of knowledge gained through financial analysis computations can provide a means for economically resolving many common exploration and development problems. Examples of such applications from the activities of exploration planning, reconnaissance, land acquisition, and development planning are presented in this paper.

Jan 1, 1969

By D. Bogunovic

The objective of this research was to conduct field-scale experiments at an operating surface coal mine in order to determine the impact of the bucket fill factor on dragline production rate and energy consumption. Data collected from a dragline monitoring system were recorded in a specifically designed software tool and the relationship among these parameters was established. an algorithm for the determination of the ?best? fill factor was developed and integrated in the software. It was determined for the analyzed dragline in the mine that energy consumption in the digging phase can be reduced by 36% and production rate can be increased by 1.4% for a bucket fill factor of about 80%, a fill distance of 19.8 m (65 ft) (i.e., 3.1 bucket lengths) and a bucket fill time of 15 sec. the method developed and applied in this study may help dragline operators to determine the fill factor that will increase production rates and reduce energy consumption in specific surface coal mines. Mining Engineering, 2011, Vol. 63, No. 8, pp. 48-53. Official publication of the society for Mining, Metallurgy and Exploration, Inc.

Jan 1, 2011

By P. R. Geoffroy

Extensive and Intensive Prospecting As often pointed out, the search for new ore deposits may be carried on along two widely divergent lines. It may be either extensive or intensive. By extensive prospecting we mean a search for mineralized outcrops conducted over large and more or less virgin tracts of land, followed by a test of the practical value of any discovery made, the test being limited to the immediate vicinity of the outcrop. Extensive prospecting, was, in fact, the only policy known to the early prospectors. of the American continent and is still the rule in the remote sections of the Canadian Shield and in the African wilderness. It can be further characterized by the lack of emphasis placed on geological and other technical means as an aid to the search for ore. However, very little virgin ground is left, nowadays, for a man or a company to test their luck, and whatever is left is so remote from the necessary means of development that any new discovery will require considerable delay and expenditures to be amenable to profitable mining. On the other band, a great many of the favourable and still unexplored areas (and this is particularly true in Canada) are overburdened to such an extent that outcrops of bed-rock are extremely scarce and extensive prospecting is nearly impossible. Intensive prospecting, to the contrary, must be understood as a detailed search for ore carried on over limited areas in districts already known to be mineralized and covering regional structures whose relation to mineral deposits bas been estahlis.hed with a fair degree ot certainty. The search for deep-seated deposits in the vicinity of successful mines is a perfect example of intensive prospecting. As a matter of fact, the majority of the geologists employed by the mining industry are engaged in some kind of intensive prospecting.

Jan 1, 1950