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By William J. Campbell

Three types of X-ray analytical instrumentation were compared for applications in the secondary brass and bronze industry. The instruments were a conventional X-ray spectrograph, a portable X-ray spectrograph, and a radioiso-topic X-ray analyzer using balanced filters. The following two general applications were considered: Rapid identification for sorting scrap metals and quantitative analyses to provide guidance in the melting and casting of alloys. Twenty-three analyzed copper-base alloys were used as standards. Although the alloys varied widely in composition, matrix correction procedures were not necessary except for copper. The conventional X-ray spectrograph provides positive identification of the alloys and quantitative values for the six elements investigated--aluminum, copper, iron, lead, tin, and zinc. Equivalent results were obtained with the portable X-ray spectrograph for those elements whose characteristic X-rays are in the wavelength range of the instrument. The radioisotopic X-ray analyzer distinguishes certain groups of alloys and provides quantitative determinations for copper, lead, tin, and zinc. The sensitivity of the analyzer was marginal for the determination of small concentrations of elements of atomic number 26 or lower.

Jan 1, 1972

By C. B. van den Berg

n this study, silver and palladium nanoparticulate inks with different metal-binder ratios were screen-printed onto a paper substrate. The printed layers comprised the metal nanoparticles and an ethylcellulose binder. The layers are not typical metal composites due to the low concentration of binder and high porosity. The electrical sheet resistivity of each particle concentration was measured, and the data fitted using the scaling law of percolation theory and the general effective media (GEM) equation. The percolation parameters, i.e. the percolation threshold and the critical exponent, for each system were determined from the fits and compared. The percolation threshold for the palladium layer (39.8 wt%) was lower than that found for the silver layer (44.9 wt%). The critical exponents determined for the palladium and silver layers were both lower than the universal value for three-dimensional percolation systems. Microscopy observations indicate that the difference in the percolation threshold for the two layers can be attributed to variations in their microstructure.

Jan 1, 2014

By Jose Carlos D’Abreu, Edelink Efrain Tinoco Falero, Mauricio Marcos Otaviano, Helio Marques Kohler

Nowadays the most important Direct Reduction - DR processes in shaft furnaces has to deal with carbon fines precipitation and DRI carburization issues. Based in a cooperative research program joining Catholic University (PUC-Rio) and SAMARCO Mining Co, a project dealing with pellets reduction and those two phenomena was established. This work analyzes kinetically the three reactions mentioned before, considering typical values for the operational variables temperature, flowrate, pressure and gas composition, parameters commonly used to control the DRI formation in the Reduction Zone - RZ of the shaft furnaces. From laboratories experimental results, the kinetic equations for those reactions were established and, using the superposition principle, generated a specific global kinetic model for the iron oxide reduction and the soot formation. Finally, using those experimental results and applying a planned statistical factorial analysis for the experiments, the numerical coefficients for each equation were calculated and the correlation factor determined for the proposed global kinetic equation.

Jan 1, 2015

By William B. Plank

NEVER before have so many men chosen the mineral technology field for their college training. In the college year 1936-'37, 7190 such students were enrolled in the 53 schools of the United States. My last study of the mineral technology schools of the United States and Canada was made for the year -1934-'35, and the current study, as the previous one was made for the A.I.M.E. under the auspices of the Division of Mineral Industry Education. Altogether, four studies of enrollment have been made. The first three were for successive college years beginning with 1932-'33. This present one covers a two-year period, for the purpose of these studies may he served satisfactorily if they are made biannually. The data on the schools were collected in the same way as for former studies, 'namely, by questionnaire, dated in this case Nov. 18, 1936. The figures reported are therefore comparable with those of former cars.

Jan 1, 1937

By H. Conrad

The strain hardening associated with the creep of magnesium single crystals at room temperatu.Je was investigated by shear tests in which the direction of stressing was reversed a number of times after creep in a <100> direction. The strain hardening was strongly anisotropic; the largest amount occurring in the direction of flow and the least 180 deg to this. The time law for creep changed from a parabolic type to logarithmic for the first and subsequent reversals of stress. For a given stress the creep strain decreased significantly for the first and second reversals and then only slightly for subsequent reversals. The logarithmic creep constant a changed in a similar manner. A linear relationship was observed between the creep strain for a given reversal and the stress. The slope for the third reversal yielded a strain hardening coefficient 12 to 16 times greater than that observed for unidirectional flow. Al-though no recovery was observed upon resting at room temperature, the hardening resulting from stress reversals could be completely removed by heating to 450" C. PREVIOUS work1.&apos; indicated that the creep rate of magnesium single crystals tested in the temperature range of 78" to 364°K decreased with time. This was attributed to an increase in internal stress resulting from an accumulation of dislocations at internal obstacles. The object of the present investigation was to further evaluate the nature of this hardening by conducting tests in which the direction of stressing is changed after previous creep in shear in a given slip direction. Previous to 1950 three investigations indicated that a Bauschinger effect3 occurred for single crystals as well as polycrystals brass in tension compression,

Jan 1, 1960

By Nan C. Jensen

Modern high-temperature metallurgical processes have created a demand for raw material for furnace parts and lining that not only will with-stand high temperatures is but will not react with the substance being melted in the furnace. Spark-plug insulators, laboratory ware, tanks for the glassmaking making industry, and saggers and kiln furniture for the chinaware and pottery trades also must be made of materials hat have high melting points. Among the minerals that can be employed for such refractory uses ore those commonly known as the "sillimanite group&apos; -kyanite, andaluste, sillimanite, and dumortierite - and the allied minerals topaz and pinite. Consideration of the occurrence, properties, qualities, uses, and sources of supply of these commodities and the markets for them constitute the subject of this paper. General Features of Kyanite and Related Minerals Kyanite, andalusite, and sillimanite ire composed of three elements - aluminum, silicon, and oxygen ? and are called aluminum silicates. The have

Jan 1, 1943

By O. C. Blade

A summary of the characteristics of motor gasoline for the winter 1951-52 is presented in table I, and for comparison, a similar summary for the winter 1950-51 is shown in table 2. Trends of some of the more important characteristics over a period of years are shown in figures 1 and 2. The results of this survey show that octane numbers have risen slightly since the summer of 1951 but are below the record levels of the winter of 1950-51. The fractions of a unit change since the summer preceding have resulted in the research and motor-method octane values being virtually the same as the figures for the survey of summer 1950. In volatility characteristics the winter gasolines have changed very little. Average Reid vapor pressures are 10.5 pounds for both grades of fuel compared to 10.4 and 10.5 pounds for premium and regular-price gasolines, respectively, of the winter of 1950-51.

Jan 1, 1952

By P Davidson

For many years, in numerous settings, the need for a language-fair and culture-fair assessment test has been identified as a significant issue for employment and selection for training of remote indigenous community members. Pivotal to the successful implementation and application of such a test is for it to gain the acceptance and trust of the local indigenous communities as a fair assessment and for it to provide organisations with an accurate predictive tool. However, when western tests have been used with indigenous groups, inherent language and cultural bias have had a significant negative impact in terms of community acceptance. These have also affected the accuracy of performance predictability. The Queensland Test was developed to overcome these problems. Originally developed for use in Papua New Guinea, it reduced training failures by 20 per cent. Later refinements were made and it was used with Aboriginal Australians. Since 2002, assessment tests have been used by the Freeport mine in West Papua to support their recruitment, selection and training processes for the local indigenous community, the Seven Suku Tribes. The initial process included the application of standard æwesternÆ assessment tests, which did not provide valid selection predictions, with community members and elders describing these tests as unfair and the organisation being concerned that the results were not accurate. A trial of the Queensland Test was conducted and a high correlation was established between the performance of FreeportÆs current Seven Suku employees as assessed by their managers and their Queensland Test results. Based on the results of this pilot the Queensland Test was successfully implemented as the primary selection tool for potential employees from these local indigenous groups. The testing materials and method gained community trust and support, with tribal elders describing the Queensland Test as a fair and suitable selection tool for their community members. Such results have sparked an interest within the Australian Mining industry, with similar results being reported from a recent trial. The Queensland Test has been implemented at a major site in Queensland and is being investigated for use elsewhere.

Jan 1, 2006

By A. Ghalambor

The objective of this investigation was to determine the sensitivity of three selected input parameters in the operational control of continuous bottom-fed thickeners used for the treatment of coal refuse slurries. The three variable parameters were "Feed Flow Rate," "Feed pH," and "Feed Solids Concentration." These three input parameters were studied under three polymeric conditions which were cationic polymer, anionic polymer, and a combination of cationic-anionic polymer. For each polymeric condition, two mathematical models were developed: one for overflow response, the other for underflow response. The combination polymers produced the best desired quality of overflow and underflow. For this polymeric condition, changes in the feed solids concentration was the most sensitive factor in the maintenance of the overflow quality, and the feed pH was the most sensitive factor for the maintenance of the underflow quality. The mathematical models generated a set of plots which would allow an operator to control and/or adjust any of the three variables to achieve optimum conditions.

Jan 1, 1989

CFD (Computational Fluid Dynamic) models have been developed and validated for a pulsed column with disk-doughnut internals, as used for solvent extraction. First a single phase model was developed to simulate the turbulent oscillating flow around the internals of the column. This model was successfully validated using detailed PIV measurements of velocity taken at eight different phases through the pulse cycle. Second, the CFD model was extended to allow for a continuous aqueous phase and a dispersed organic phase (kerosene) flowing counter-currently. The model was a two-fluid model that accounts for droplet breakup and coalescence, and solves for droplet size distribution using a population balance model incorporated into the CFX4 package. PDIA (Particle Droplet Image Analysis) measurements were taken on a pilot scale solvent extraction pulsed column to determine droplet size distribution for calibration and validation of the CFD model. The measurements were made under pulsing intensities ranging from 10 mm/s to 32.5 mm/s.

Jan 1, 2007

By J. A. L. Napier

An analytical solution to the best choice of cutoff grade for a mine is deduced for an assumed model of selective mining. It is found that this choice is determined by the constancy of a special function, the Hamiltonian, over the life of the mine. It is suggested that the appropriate constant value for this function should be determined by the expected long-term average of the paylimit. In that case, the optimum profile can be calculated at each point in time according to the prevailing working cost and product price. In particular, a decision can be made between operation at the true paylimit or at the subsidized paylimit implied by either the lease and tax formulas or the assistance formula for gold mines. It is also shown how the basic formulation can be extended for &apos;use in the determination of the optimum joint paylimit for two products over the life of the mine.

Jan 1, 1983

Draftsman and transitman for coal-mine work in middle West. Salary $125 per month. No. 277. Surveyor and mine sampler for development company in Mexico. Applicant must be willing to interest himself in mine sufficiently to, act as assistant to the superintendent and be able to take charge in case the superintendent should be incapacitated at any time. No. 326. A copper company in Mexico desires services of engineer to act as chief chemist and flotation operator. No. 327. Instructor in mining and metallurgy, the work being chiefly in mining for college in middle West, to start Dec. 1. Salary $1200 to $1400. No. 328. A copper company in Mexico is increasing its force of underground foremen and desires the services of two men competent to act as assistant underground foremen. Chances for advancement excellent. Knowledge of Spanish is required. Salary to start $200 per month. No. 329. Young man for core-drill work for coal company. No. 330.

Jan 7, 1918

GWILLIAM H. CLAMER (Philadelphia, Pa.).-About 16,000 tons of tin is used annually in the production of white metals. The real reason for using the so-called genuine babbitt, which is a high-tin base babbitt, perhaps in the majority of cases, is that tin has always been. a high-priced metal and people naturally believe that what they pay a high price for must be good. Mr. Jones has shown that the common metal, lead, is a superior base for most purposes for Which babbitt metal is used. The addition of lead is often looked upon as adulterant to genuine babbitt, and specifications for this reason rigidly restrict the lead content. A sub-committee of the Society for Testing Materials, at the meeting in June, presented tentative specifications on babbitt metal, in which were included twelve formulas, containing from zero to: 20, per cent. of tin, and several containing from 65 and 92 per cent. Babbitts. containing

Jan 1, 1919

The metallurgical testwork program is generally the most important critical path item for the completion of a bankable feasibility study and hence can become the critical parameter for financing of potential mining projects. This paper presents generic detailed testwork programs suitable for bankable feasibility studies for a gold leaching and polymetallic flotation study. The design of the metallurgical testwork program for each of the two differing processes is discussed and the critical factors that effect the selection of the testwork programs are highlighted. The importance of the metallurgical testwork results in predicting the metal recoveries and cash flow prediction for the project is presented. The detail of the testwork programs costing is broken into activity based methods based on the laboratory and management hours/costs, such that generic rule of thumb costing guidelines can be generated. The scheduling, costing and importance of the metallurgical testwork program to process feasibility studies are discussed in this paper.

Jan 1, 2000

By C. H. Bucknam

A suite of ore and waste rock materials was selected for the interlaboratory testing of combustion-infrared ("Leco") methods used to estimate carbonate and sulfide minerals present in test materials. The objective of the study is to develop ASTM standard methods to be used for metallurgical characterization of ore, acid drainage prediction for ore and waste during ore body evaluation, and for ore and waste control during the active mining of ore deposits. The results may be interpreted for classification of the materials according to their carbonate-sulfide or acid-base characteristics based on net carbonate value (NCV). The test materials were processed by x-ray diffraction and x-ray fluorescence (XRD-XRF) at Newmont Metallurgical Services (NMS) to obtain a semiquantitative mineralogical composition. Results of the interlaboratory testing for total carbon-sulfur, pyrolysis loss carbon-sulfur and hydrochloric acid residual carbon¬sulfur are compared with the mineralogical composition to aid in interpretation of the NCV classifications of the samples.

Jan 1, 2002

By Vincent H. Hartung

The process of estimating tailings deposition for a given basin is a relatively tedious process without dedicated software tools. The amount of time required to generate a tailings surface for a given set of conditions tends to limit the number of design alternatives that can be considered for a particular project. Recent innovations in the Surpac Vision mining software include the widely used scripting language TCL (Tool Command Language) that brings with it the ability for non-programmers to extend the software functionality beyond mining applications alone. A software tool was developed using the Surpac Vision scripting language to take advantage of 3D visualization and create a flexible tailings modeling solution. The result is an application that removes much of the drafting overhead required to produce a tailings surface. It provides the means for reviewing alternatives and performing sensitivity analysis with variables such as pond elevation, dam or spigot location and height without a significant increase in overall time for a project.

May 1, 2001

In a world dependent in part on the consumption of depletable natural resources, development of new areas of mineralization is a necessity for replacing those reserves. Exploration, which is the initial task of replacement, is an information-gathering process which supplies input for management decisions on mine development. If the demand for resources is the driving force of exploration, then the scientific basis for its pursuance is the hypothesis of anomalous mineralization in a metallogenic province, which is tested by measuring physical characteristics of natural phenomenon. The resulting data are reduced, analyzed, and interpreted to locate expressions or responses associated with possible ore bodies. The process is, in fact, repeated in ever increasing measurement detail to increase the accuracy and precision of information for decision making. Exploration ceases when management makes the decision to develop a mineralized area, to hold a property for more favorable market conditions, or to drop a property because it is not economically viable.

Jan 1, 1979

By Forrest T. Moyer

THIS CHAPTER of the Minerals Yearbook contains injury experience and related employment information for the coal-mining, coking, oil and gas, peat, and native asphalt industries in the United States for 1962. Injury experience is measured by the number of injuries sustained per million man-hours of exposure in each industry. No attempt has been made to combine these data and present rates reflecting the mineral-fuel industries because the hazards of the separate industries are not comparable. Tabulations showing the trend of injuries and employment for all mineral industries are presented in volume III of the Minerals Yearbook. COAL The injury-frequency rate for the coal-mining industry of the United States increased less than 2 percent, according to reports received by the Bureau of Mines. The number of fatal and nonfatal injuries per million man-hours in 1962 was 45.86, based on final data for anthracite mines and preliminary data for bituminous coal and lignite mines.

Jan 1, 1963

By Todd M. Ruff

A training software package for new mine employees, called Miner Training Simulator (MTS), has been developed by researchers at the National Institute for Occupational Safety and Health. MTS is a computer-based tool that allows a trainee to enter a simulated mine and interact with his/her surroundings in order to learn basic mining concepts, safety procedures, mine layouts, and escape routes. The training simulator software and instructions for its use are described in this report. Also, each mine using the software will have different requirements with regard to safety training. To customize the simulator for these differences, an interpreted scripting language is used to define interactions between the trainee and the virtual mine and objects in it. The scripting language, called Tool Command Language, uses simple commands to control various actions in the simulation, such as sounds, safety messages, hazards, and movement of objects. The basics of the scripting language are described here, along with many examples and instructions for building a script for MTS.

Jan 6, 2001

By S. K. Kawatra, C. A. Hardison, J. Gurtler, T. C. Eisele, K. Lewandowski

Acid soak tests were used to measure the effectiveness of binders in highly acidic conditions to determine their suitability for use in copper heap leaching. Soak tests involved placing the agglomerates on a screen, soaking them in a solution that replicates the pH of the raffinate used in a heap leach, and measuring the quantity of fine particles that passed through the screen. A wide range of binders were evaluated which had potential for functioning in acidic solution. Only a few binders were effective, with the best-performing binders being nonionic polymers designed for dust suppression applications. The most effective binder prevented all but 1.86% of the fines from being released and passing through the screen, while binderless agglomerates allowed as much as 29% of the fines to pass through the screen. The soak test developed for this study provides a useful method for rapidly identifying promising binders at a low cost, and for examining effects such as curing conditions on agglomerate quality.

Jan 1, 2005