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By K. J. Miller

A laboratory electrophoresis column was designed to separate pyrite from fine coal by utilizing an observed difference in the electrophoretic mobilities of the two materials in water. The apparatus worked well when tested with synthetic mixtures of coal and pyrite, but some modifications in design and procedure were necessary to provide a sharper separation. After these changes were made, the column was tested with a high-pyritic-sulfur raw coal sample. The column successfully fractionated the sample, removing not only the pyritic refuse, but a siliceous refuse as well. The invest ion demonstrated on a laboratory scale that pyrite and other impurities can be separated from fine coal by electrophoresis.

Jan 1, 1970

By E. J. Rapperport, J. P. Pemsler

We have made calculations to evaluate the sensitivity of atomic absorption as a technique to measure vapor pressure changes with temperature. Our conclusion, supported by the experimental findings presented in this work, is that the ultimate sensitivity of the technique is well below lo-' Torr. This magnitude of vapor pressure sensitivity makes the method extremely attractive for thermodynamic studies. Atomic absorption techniques have been used previously in this connection by Scatchard and Boyd' and by vidale2 with a much lower sensitivity reported. Scatchard and Boyd's work measured cadmium pressure over Ag-Cd alloys in the range 0.02 to 0.3 Torr, and Vidale estimated that sensitivities of only 10"5 to 10"6 Torr are to be expected. Atomic absorption appears to be particularly well-suited to thermodynamic studies for several reasons: A) It is extremely sensitive; our experiments indicate an ability to measure vapor pressure changes of 10"9 Torr. B) It is highly selective; there is seldom interference among the resonant wavelengths of the various species. C) It may be performed in an absorption cell under static conditions. This alleviates such problems as surface impoverishment of alloys, attainment of equilibrium, and temperature measurement and control. D) Simultaneous, or near-simultaneous, vapor pressure measurements may be made for several elements in a given system. Experimental. The physical basis of the technique is the highly selective absorption of particular wavelengths by specific atomic species. In most atomic absorption work the element of interest is incorporated into a hollow cathode lamp to provide a characteristic spectral source of high intensity. The spectra lines characteristic of the element in the cathode are attenuated by atoms of that element in the radiation path. Radiation from silver or cadmium hollow cathode lamps was directed along a path containing a 10-cm evacuated silica cell. The cell was positioned within a silica windowed furnace and contained silver, cadmium, or an Ag-Cd alloy. As the furnace temperature was elevated, the number of atoms of the absorbing element in the vapor phase within the cell rose, and the resonant radiation was increasingly absorbed. Intensities were measured by passing the radiation through a Techtron Model AA-4 one-half meter grating atomic absorption spectrometer equipped with a photo-multiplier detector. In order to minimize instabilities in the source, the hollow cathodes were allowed to warm up for several hours and were run at only 2 5 to 30 pct of their maximum rated amperage. In addition the attenuated beam was monitored before and after each reading. The attenuation of resonant wavelengths may be related to vapor pressure by the following relationships.

Jan 1, 1969

By Myung Bae Kim, Yong Hack Lee, Woll Seung Lee

The Slag Fumer is the first Ausmelt furnace system adopted at the Onsan Refinery of Korea Zinc. This plant continuously treats the QSL lead smelting slag in the molten state. It has developed progressively since its first commissioning in October 1992 and has generated a confidence that it can produce an environmentally acceptable slag for use in cement manufacture and recover the zinc and lead in the slag as a fume oxide. This paper provides the operating experiences accumulated during the last eight years of operation, a summary of problems and solutions, and the current status of the operation.

Jan 1, 2000

By R. G. L. McCready, G. Dr. Heinrich, V. I. Lakshmanan

The objective of this study was to prove repeat loading capacities of physically stabilized fungal biomass from Penicillium sp. for the removal and recovery of uranium from mine water (Denison Mines). The testwork was carried out on a bench scale in small columns and proved that it is possible to stabilize the biomass in an inorganic compound. A lifetime of 10 loading-eluting cycles of the stabilizer biomass product was obtained by additional pretreatment. Sodium carbonate proved to be an effective elution medium. Loading and elution can be controlled by the pH values of the column. The effective loading capacity until the breakthrough point is approximately 70 % of the overall loading capacity. The loading capacities of the stabilizer biomass product are comparable to that of the original biomass. Uranium recoveries of 90 to 99 % were achieved during the loading and eluting under optimized conditions. Depending on the used biomass the described process might be applicable to remove uranium or other dissolved heavy or rare metals from effluents.

Jan 1, 1989

By Yoshio Waseda

A laser flash method has been applied to obtain the thermal diffusivity values of Zr55Al10Ni5Cu30 alloy in the liquid, glassy, crystallized and supercooled liquid states. The electrical resistivity of this particular alloy was measured in the glassy, and crystallized states by a direct current four probe technique. A specific heat of Zr55Al10Ni5Cu30 alloy was also determined by a differential scanning calorimeter in the glassy state. On the other hand, thermal diffusivity values for two alloys of Zr60Al15Ni25 and Zr65Al7.5Cu27.5 were measured in the crystallized and liquid states. The thermal diffusivity values of three Zr-based alloys in the liquid state are summarized in the linear equations with positive temperature dependency and it is noted that the lower the thermal diffusivity values of Zr-based alloys at liquidus temperature, the lower the critical cooling rate to obtain metallic glass phase becomes. The thermal diffusivity values of Zr-based alloys were compared with those of Pd-based alloy case. These results suggest that thermal diffusivity of alloy liquids might be an indicator of the glass-forming ability of Zr-based and Pd-based alloys.

Jan 1, 2006

By Grinbaum B, Stevens G. W, Dalton R. F

Many hydrometallurgical processes produce large amounts of acid waste. This is illustrated by the copper S/X-E/W process which produces a bleed from the electrolysis tank house in the form of a concentrated sulphuric acid stream. Currently, the bleed stream is necessary to remove impurities such as iron that decreases the efficiency of the electrowinning process. However, this comes at a high financial cost owing to large quantities of make-up sulphuric acid required. A process has thus been developed with Zeneca Specialties (UK), ICI Australia and Gunpowder Copper Co at the University of Melbourne for the recovery of sulphuric acid from copper tank house bleed liquor. The recovery process uses the method of solvent extraction. Solvent extraction has the advantage of being a well-established technology in the mining industry and will reduce the environmental impact of the S/X-E/W process, as all additional chemicals can be completely recycled. A simplified diagram of the process is shown in Figure 1. Tank House

Jan 1, 1997

By D. E. Norquist, J. E. Moeller

The results of wear on marked balls, 4, 31/2, 3, and 2 in. diam are given. All balls were forged steel of practically the same chemical analysis and hardness. The results indicate that balls in a given mill for a given length of time will have equal diameter losses, regardless of size.

Jan 6, 1950

By P. B. Scotland

THE mines of the Arizona Copper Co. are situated in the Morenci-Metcalf copper district in southeastern Arizona. This copper-bearing district covers a triangular mountainous area of about 3 square miles, rising abruptly from the gravel plateau of the surrounding country. In this area, an immense intrusion of porphyry has displaced, shattered, and engulfed the shales, limestones, and quartzites formerly bedded on the basal granite. Outcrops of oxide ore were discovered in 1873, and these surface ores were found to connect in depth with large bodies of high-grade oxide ores in the limestones and shales. The smelting of these ores in blast furnaces continued until about 1893, when the rapid exhaustion of the high-grade ore led to the discovery and exploitation of the low-grade sulphide ores in the adjoining porphyry. Methods of concentration were then devised and the low-grade ores finally rendered profitable. The Arizona Copper Co. and the Detroit Copper Mining Co., operating in the same district, were the pioneers in the successful development of the low-grade "porphyry" properties of to-day. The largest mines of the Arizona Copper Co. are the Humboldt and Clay at Morenci, and the Coronado, Metcalf, and King at Metcalf. These mines produce about 4,000 tons daily of concentrating ore containing from 2.5 to 2.8 per cent. copper. The topography of the country is very rugged and mining operations are conducted principally through adit levels. A few of the mines are opened by shafts, the deepest being 1,100 ft., in the Coronado mine. ORE OCCURRENCE The low-grade sulphide ore occurs as: (1) disseminated deposits in the main stock of quartz porphyry; (2) lode deposits in fault fissures in granite. The high-grade oxide ores were found as tabular deposits in limestone and shale close to contacts with porphyry. Low-grade oxide ore formed the outcrop of some-' the sulphide orebodies; the majority of the outcrops, however, were barren.

Jan 2, 1915

By Thomas G. Langton

The demand for mineral raw materials, especially in the major industrialized nations, has grown rapidly during the past three decades. One consequence of this growth has been an increasing reliance by the large industrialized countries upon nondomestic mineral supplies. These mineral supplies, to a large extent, have been developed by capital from the major industrialized countries. Until recently, most foreign mining ventures were either wholly-owned subsidiaries or joint ventures between two or more mining companies. The recent rise of economic nationalism has substantially changed the business climate and parameters under which foreign investors operate. This paper describes some of the underlying reasons for this change and notes how investors have adapted to the new business conditions.

Jan 1, 1974

Mr K.C. Owen started his mining career as a learner official after matriculating at the Parktown Boys' High School, Johannesburg in 1967.

Jan 1, 1991

By Zhang Youdi

A two-step approach has been developed for surface mine short term planning by the authors. The first step is mid term control and planning by the use of Goal Programming. This step gives optimal results for mid term planning (i. e. yearly or quarterly mine plan) as well as a macro control for short term planning (i. e. monthly or weekly plan.) The second step of the approach deals with short term production scheduling by the application of CAD technique and Systems Simulation. An interactive color character graphic design system has been developed with a software package. The menu-driven and module- structured package provides sufficient functions for surface mine short term planning and makes the model very flexible and user-friendly. This model has been applied to a large surface coal mine for short term planning optimization. Satisfactory results have been obtained. It is concluded that for complicated mining conditions this two-step combined approach gives an optimal control of mid term planning, makes the short term planning easier to avoid blindness; it has been proven that the Goal Programming is a powerful tool for solving multi-objective decision-making problems; guided by GP mid term planning, the CAD technique and simulation software package for short term planning are able to be concentrated on their practicality and flexibility.

Jan 1, 1992

By S. F. Guo, Z. F. Zhan, X. L. Huang, Y. Zou, S. W. Qi

"FLAC3D is an important numerical analysis software to study dynamic response of rock slope. In application of the program, the common issues such as absorbing boundary and the method to apply wave have been well studied. However, effects of model mesh size, damping and width of slope are still unknown. In order to make the result more convictive, this article has discussed the above issues systematically. It found that when the maximum mesh size is smaller than 1/10~1/8 of the smallest wavelength, the mesh size is smaller, the computational accuracy is higher. Meanwhile, values of damping and width of slope have no effect on the result. Additional, results of FLAC3D modeling on wave transmission across rock joints agree well with analytical solutions, so it has verified the capability and accuracy of FLAC3D on dynamic response of rock slope.INTRODUCTIONChina is a mountainous country accompanied with many earthquakes. Thousands of geological disasters are triggered by the Wenchuan Earthquake in Sichuan Province, and the majority of the disasters are landslides induced (Xu et al., 2009). Meanwhile, the paper (Li et al., 2003) points out five significant issues about dynamic loading in the area of geotechnical engineering, which includes the study of rock slope stability under earthquakes, and the dynamic response of rock slopes is one of its important study issues."

Jan 1, 2015

The mining industry continues to faces significant challenges due to increasing resource constraints (quality of ore bodies, water, energy, human resources) and increasing license to operate requirements (safety, health, environment, location) from society, employees and shareholders. Technology advancements and hence research are necessary to ensure that the industry remains viable in this changing environment. Collaborative research is an important part of a company's research portfolio and offers the opportunity for the industry to work on generic issues that it is facing. Obvious benefits include the reduced cost to individual companies by sharing the costs, the opportunity to leverage government funding and the opportunity to conduct longer term projects resulting in skills development (PhD and MSc). Limitations of collaborative research include the reduced focus on company specific issues and the loss of competitive advantage from owning the outcomes of the research. The challenge for researchers and research managers is for them to demonstrate the value derived from longer term, pre-competitive collaborative research. The competitive advantage is not necessarily derived only from the outcomes of the research but rather from the company's ability to direct the research, translate the generic research outcomes to address company specific issues and to implement improvements at its operations. Implementation remains the greatest challenge. In this paper, case studies of selected collaborative research projects are presented to demonstrate key success factors required for implementation of research outcomes. This is an ABSTRACT ONLY. A full-length paper was not prepared for this presentation.

Sep 13, 2010

By N. S. Petersen

As part of the Demand Evaluation Program of the Bureau of Mines to determine future needs for minerals, a study was instituted to develop and describe a methodology for approaching the problem of substitution between mineral commodities and between mineral commodities and other materials. The report comprises three sections: A review of general factors relative to substitution, a case study of the effect of substitution on zinc die-casting markets in recent years, and a general methodology for reviewing materials substitution with specific emphasis derived from reviewing substitution in the domestic zinc die-casting markets.

Jan 1, 1971

By R. E. Ogilvie, E. T. Peters

The X-ray Kossel-line method has been used preaioz~sly for measuring lattice parameters to accuracies of 1 part in 100,000.5 A second application of this method is described for determining the crystallographic orientation of a randomly positioned single-crysta1 spherical volume that can he as small as 50 µ in diameter, within accuracy limits of ±1/2 deg. The theory, experimental procedure, and interpretation of Kossel-line patterns and an experimenta1 verification of the predicted orientation relationship of the cph k and fee a Cu-Si phases are presented. This orientation relationship can be described as (111)a, (00.1)k; [110]a [11.0]k. In addition, the lattice parameter of the a phase was found to he a. = 3.62154 ± 0.00014Å. The Kossel-line method when used in conjunction with electron microanalysis is shown to he capable of providing a complete chemical and structural analysis of a given crystal. THE most easily accomplished methods for determining the orientation of a single crystal are variations of the Laue X-ray diffraction method. Although certain materials can be oriented to within ± 1 deg accuracy by observation of exterior macroscopic features, such as etch pits, cleavage faces, or growth features, the Laue method is generally preferred for routine laboratory application. Both back-reflection and transmission patterns are coordinated by appropriate reference charts and are plotted in terms of reflection plane poles (normals) on a stereographic projection. Orientation is deduced by relating the pole distribution (which is fixed by the crystallographic symmetry of the specimen) to two specified external reference directions. The Laue method has several limitations. 1) Orientation can rarely be determined to better than ±l deg accuracy. Principal errors involve inaccuracy in specimen-to-film distance, measurement confidence of individual Laue spots, and stereographic plotting. 2) Because of the indeterminacy of the X-ray wave length diffracted to a given spot, it is not possible to determine supplementary crystallographic data, such as interplanar spacings and lattice parameters. 3) The method is generally limited to specimens of cubic symmetry or to specimens of high symmetry and known structure. 4) The relatively large cross-sectional area of the incident X-ray beam generally precludes the measurement of relative grain orientation in a polycrystalline material.* _____ Several of these limitations can be overcome by application of the Kossel-line method, which has been previously employed for precision lattice-parameter determinations.'-= For this method, a point source of divergent monochromatic X-rays is generated within the crystal by means of an incident electron beam. The divergent X-rays which fulfill the Bragg law are diffracted by the specimen and are recorded on a film placed either in transmission or back reflection. Analysis of the film yields a direct measurement of orientation and lattice-spacing values to an accuracy of ±1/2 pct. As analyses can be obtained from spherical specimen volumes as small as 50 µ in diameter, the method provides a means for structural analysis of second-phase or impurity precipitates within a given matrix. The primary limitation of the Kossel-line method is the requirement for an electron microanalyzer or similar apparatus capable of producing a finely focused electron beam. This paper is designed to present the theory, experimental procedure, and geometrical interpretation of Kossel patterns. The experimentally determined orientation relationship between the k and a phases occurring in the Cu-Si system and a precision measurement of the a lattice parameter are presented as a practical application of the method. THEORY OF KOSSEL LINES Divergent X-ray beam photography utilizes an effective point source of characteristic X-rays which, when diffracted from a single crystal, form numerous diffraction and absorption cones that are recorded on film.7 The cones generated from a source lying within the crystal are called Kossel lines.' Although the X-ray scattering from a divergent point source contained within a crystal is described in terms of Laue dynamical theory,9 the directions of the diffracted spectra can be ade-

Jan 1, 1965

By Samuel Taylor

IF I LIVE another fourteen months and am still con-nected with the coal industry, I shall then have com-pleted a half century with it. Since May, 1874, when .I first entered the bituminous workings as a miner, I think I have held almost every position connected with a mine except possibly that of mule driver, for which I was unfitted by reason of my religious upbringing. We are all agreed, at least I have not heard it contra-dicted, that there is serious over-production in the bituminous industry. This has come about in various ways and is easily explained. During the Fuel Admin-istration, I recall making an estimate of the possible output of the bituminous mines of the country provided they were given a full force of men and a full-car supply; my estimate was a little over a billion tons a year. A few months ago, the late Francis H. Peabody, of Chicago, made a practically identical estimate. If, however, both of these conditions should happen con-currently, there would very soon be no market for the coal, and many of the mines would close down. Even today, if 10 per cent. more cars were furnished, to the bituminous mines, market prices would drop very seriously.

Jan 4, 1923

By Axel Preusse

To detect improper deformations of a roof bolted roadway in order to reduce inner mine damages in the most early stage and to initiate suitable countermeasures if necessary, several different measurement systems were used for monitoring a roadway's stability on the hardcoal mine "Auguste Victoria" (DSK AG). In this paper the different convergence measurement procedures are described and their respective results are introduced. Subsequently the results of the single measurement methods and procedures are correlated with each other.

Jan 1, 2000

By H. J. B. Couto, J. G. S. Puelles, M. L. Torem, R. H. Rojas, A. G. Merma

Understanding the limits of fine particle flotation is fundamental to achieving a significant and selective separation. Conventional flotation processes are not suitable to treat these particles because of their low collision efficiency. This problem can be overcome by decreasing the bubble size or by increasing the apparent particle size. However it is worth noting that the use of small bubbles or micro bubbles also involves some disadvantages such as their low momentum resulting in a slower process comparing with conventional flotation. Electroflotation is an attractive alternative for treating fine particles with small bubbles less than 100 µm, generated by the electrolysis of water. In this sense, this study assesses the effect of current density and pH on bubble size in a binary electroflotation cell. An increase in the bubble generation rate was reported with an increase in current density. In addition, at acid pH values, the size of oxygen bubbles increased and conversely decreased at basic pH values; this may be due to the electrostatic attraction between the oxygen bubbles and the anode resulting in a greater nucleation time. An opposite trend was observed with the hydrogen bubbles. These results are in agreement with their electrokinetic studies, which reported that at acid conditions the bubble surface may be positively charged for both the hydrogen and the oxygen bubbles. Finally the bubble size was slightly affected by the electrolyte concentration, resulting in smaller diameter bubbles at higher concentrations.

Jan 1, 2016

By Xingshi Yang, Ghislain Bournival, Seher Ata

"Particle-laden interfaces are a fundamental research topic in froth flotation since the process involves particle-coated bubbles in both the pulp and the froth phase. In most experimental studies the characteristics of the particle layer in multi-bubble systems are poorly defined. An experimental setup has been developed based on a Langmuir-Blodgett (L-B) trough. The modified trough allowed introducing an air bubble beneath the particle monolayer formed at the air-water interface which made the study of the interaction between the bubble and the monolayer under various pH values possible. The monolayer characteristics of the particles were also studied and compared in terms of surface pressure (?-A) isotherms and packing factor. On compression, the particles formed branched structure at high pH whereas a uniform monolayer was formed at lower pH. Observations related to the behavior of particles during compression and expansion cycles, and the coalescence of a bare bubble with the flat particle laden interface were provided and the implication of the results for flotation process was discussed.INTRODUCTIONFroth flotation is known for its versatility and ability to concentrate low-grade, complex ores. It is considered a physico-chemical process in which particles attach to air bubbles, depending on their hydrophobicity as well as other factors, and are carried to the surface to form a froth layer. Reagents are used to stabilize bubbles and the froth layer (Pugh, 1996). However, particles, which are carried by the bubbles or entrained, significantly contribute to the stability of the froth phase (Ata et al., 2003; Zanin et al., 2009; Bournival et al., 2015a). Their relevance in mineral processing has led to a number of fundamental studies on the effect of particles and their properties on the process of froth flotation.Flotation systems are particularly difficult to characterize due to the broad range of properties of particles (e.g. size, liberation, hydrophobicity, etc.) and inconsistent operational conditions (e.g. changes in water quality, reagent addition, etc.). Several studies have made the use of well characterized particles in laboratory conditions. Such studies allowed the finding of an optimal contact angle for the stabilization of the froth phase (Johansson and Pugh, 1992; Ata et al., 2002). Froths have a large number of bubbles so that individual interactions are not observed. The study of two bubbles allows to determine the stability of the bubbles, with particles, and to some extend the stability of the bubble-particle aggregate (Gourram-Badri et al., 1997; Bournival et al., 2015b). The removing of particles between two bubbles may also be studied from a Scheludko cell (Johansson and Pugh, 1992) or by observing a bubble with a flat interface (Sethumadhavan et al., 2002). However, these systems provide limited information on the arrangement of the particles."

Jan 1, 2018

By R. C. Ellman

In the United States, the consumption of lignite and subbituminous coals is increasing. A variety of energy-oriented companies have leased large blocks of reserves, new large power plants are in operation and being constructed, and new producing mines are being developed. The Bureau of Mines has maintained an active interest in the utilization of low-rank coals for many years. In 1951, with the completion of the Bureau's Grand Forks Coal Research Laboratory, an organizational unit was established for studies in lignite preparation. Since that time, numerous investigations have been completed. This research has dealt almost exclusively with lignite, but since subbituminous coals have many similar characteristics, the findings can often be applied to both types of coal.

Jan 1, 1970