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By D. E. Traut

A fluidized countercurrent ion-exchange system was developed, operated, and evaluated by the U.S. Department of the Interior, Bureau of Mines. The system consisted of integrated multiple-compartment absorption and elution columns in which the solution flows were continuous except for short periods when resin increments were withdrawn. The exchange of uranyl carbonate between a simulated in situ uranium leach liquor and a strong-base ion-exchange resin together with the subsequent elution with an ammonium chloride solution was studied. The effects of the number of sections, section height, amount of resin withdrawal, solution flow rate, and column diameter were investigated. The kinetic and equilibrium relationships for the absorption and elution steps were also examined. The experimental data indicate a strong interdependence between variables. Solution retention time appears to be a major limiting variable in the absorption process, while resin residence time is the determining factor in the elution process. The column was efficient over a range of conditions, but close control was needed for optimum operation.

Jan 1, 1978

Choosing the correct delay time for many blasting applications is an important and critical blast design parameter for controlling fragmentation, muckpile shape, swell, digability, throw, ground vibration and airblast. BAl and its affiliates have monitored thousands of full scale blasts in a variety of field conditions, spanning over 15 countries, with sophisticated blast monitoring instrumentation. In some blast environments, a small change in the choice of delay times used had a dramatic and pronounced effect on the overall blast results. In other blast environments, large changes in the choice of delays used had absolutely no effect on the final results in terms of specific outputs. In environments which were sensitive to the delay selection, the type of explosive, dynamic response time of the rock mass (TMIN), integrity of the material, burden and rock mass geometry, all played a very important ,role.

Jan 1, 1998

By J. Böhlke, B. Friedrich, E. Hecker

The legislation for the disposal of heavy metals contaminated substances is still going to be tightened up in the future. The main criteria for the utilization or deposition of these residues are the content and the water solubility of these metals. Through this, the use of slags from the lead-and zinc-industry in road building may become limited or even not possible at all. From an economic point of view this would lead to Pb/Zn losses and costs for safe dumping. This paper investigates the feeding of the reducing agent via hollow electrode DC smelting and the yield of metal reduction. After carrying out thermodynamic calculations, the process window conditions for electric-arc furnace tests were determined. Doing this, the zinc could be reduced, evaporated and recovered as an oxidic intermediate product flue dust, while the lead was present either in flue dust or in metallic form. The zinc content in the final slag could be reduced by up to 90%. The slag product has undergone an eluation test which allows it to be used as building materials. Keywords: zinc reduction, lead reduction, hollow electrode, slag treatment, electric arc furnace

By M. H. Rogers

Coal has been at the forefront of mankind?s drive to improve his quality of life and also for sustainable development, from the Industrial Revolution onwards. The international coal industry today is large, with some 3,7 billion tons being produced and consumed in 1997. South Africa is an important participant in the coal industry, selling some 220 million tons in 1997 of which 64 million tons were exported. It is the second-largest thermal coal exporting country in the world. Despite the size of the world coal industry, it is not immune to change. The address examines growth projections for the industry and the change drivers that will impact on it in the future. Environmental pressures, the most important of which being the climate change debate, the Kyoto Protocol arising from this debate and the development of clean coal technologies, to reduce the impact of coal production and usage on the environment are considered. Other major change drivers considered are competition from other sources of energy and that between coal producers, the deregulation of the electric power industry, corporate restructuring and for the South African producer, legislative reform. The declining (real term) coal price, the consequent squeeze on margins and the need for producers to actively contain costs is covered. Technology has, in the past, been the driver behind the growth and change of the South African coal industry and its future role in ensuring that coal is the fuel of choice for continued improvement in standards of living and economic development is addressed.

Jan 1, 1999

By William O. Vanderburg

This report3/ gives the results of a reconnaissance of mining districts in Eureka County, Nevada, made from September 25 to October 20 and from October 27 to November 5, 1577. During this time, virtually all the districts were visited and many data obtained on active and inactive properties. This report covers the locations of the various districts, geological background, ownership and brief descriptions of mines and prospects, information on past and current operations, and, other data likely to be useful to those interested in the development of our mineral resources. From the viewpoint of past production in the county, the silver-lead-gold deposits at Eureka have been tie most important, followed by the silver deposits at Cortez and Mineral Hill. The period of greatest activity in the foregoing districts was from 1870 to 1990, when Eureka was one of the principal mining areas in Nevada; the production of lead was sufficient to affect its price in all the commercial centers of the world. Eureka also merits the distinction of being the birthplace of the silver-lead smelting industry in the United States.

Jan 1, 1938

By T Hirsi, M Weatherseed, T Ritasalo

Cooling tower design has not advanced significantly in the last decade. Recognising this, Outotec has developed an innovative horizontal outflow cooling tower with increased performance compared to conventional design cooling towers.Outotec® Cooling Towers operate today in applications such as spent electrolyte cooling in zinc plants and for gypsum removal before copper solvent extraction. In such applications the use of this latest design has enabled increased production and lower maintenance costs in the downstream operations.In actual operations, the cooling performance has been confirmed at start-up, and has demonstrated that the towers operate in accordance with the CFD modelling. In the last three years these towers have proven themselves in commercial operation to operate with high efficiency and availability.This case study will outline comparative data, collected over two years at a site where both Outotec and conventional cooling towers are operating. The data shows that Outotec cooling towers require less than half the maintenance time of conventional cooling towers, when adjusted to a total solution flow basis. A close partnership approach with the site has allowed continual development, ensuring high availability and high performance.Experience with previous cooling tower installations guided the development of maintenance philosophies and procedures; this resulted in a design where maintenance intensive components were accessible from the top of the cooling tower. This allows safe access to components and maintenance with little or no downtime.CITATION:Hirsi, T, Ritasalo, T and Weatherseed, M, 2015. Improving cooling tower performance with innovative horizontal outflow design, in Proceedings MetPlant 2015, pp 396–402 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By A. D. Thomas

Some years ago, the authors developed an analysis of non-Newtonian pipe flow based on enhanced turbulent microscale and associated sublayer thickening. This analysis, which can be used for various rheologic modelling equations, has in the past been applied to smooth-walled pipes. The present paper extends the analysis to rough walls, using the popular Bingham plastic equation as a representative rheological behaviour in order to prepare friction-factor plots for comparison with measured results. The conditions for laminar-turbulent transition for both smooth and rough walls are also considered, and comparisons are made with earlier correlations and with experimental data.

Jan 1, 2007

By J. W. Town

This report summarizes the results of laboratory investigations made by the Bureau c! Mines on the recovery of mercury from caustic sulfide solutions by aluminum precipitation and by electrodeposition. Statistical methods were used to design the experiments and evaluate the resulting data. Precipitation studies demonstrated tint metallic mercury could be recovered from mercury sulfide-sodium sulfide solutions with aluminum. Other metals and their salts and aluminum, salts precipitated only black mercury sulfide. Over 95 percent of the mercury was precipitated from solutions prepared with reagent-grade chemicals and from cinnabar leach solutions. Two equivalents of aluminum were required to obtain 95 percent precipitation of the mercury. Under optimum conditions 1 gram of aluminum precipitated from 4 to 7 grams of mercury; the excess Aluminum was recovered for reuse. The effects of time and temperature on the precipitation of mercury were minor when compared with the effects of mercury concentration and aluminum equivalents. The particle size of aluminum had no significant effect over the ranges studied. When aluminum was used as a precipitant, the mercury concentration in solution was reduced to below 1.0 grams per liter. Adding arsenic and antimony sulfides to the mercury solution resulted in their coprecipitation with the mercury when the aluminum was added From 95 to 99 percent of both the arsenic and antimony were precipitated as metal, which amalgamated with the mercury.

Jan 1, 1962

By Pat McLaughlin

Blast design in the construction industry has often been based on past practice or powder factors. This is to some extent understandable, since construction projects do not have the longevity of mining or quarrying operations and therefore have less opportunity to pursue potential improvements. The main concern of the operator is whether or not the technique will work, and at what cost to the downstream processes. Time, not long term savings, is of the essence.

Jan 1, 1994

By T. C. Davis

Nine organic derivatives of fluorine, silicon, boron, and aluminum were purified for thermodynamic studies using distillation, zone melting, and gas liquid chromatography, The unusual properties of these compounds required the development of special techniques for handling and purification. To determine purities of purified samples, new techniques for analyzing spectral data were developed.

Jan 1, 1965

A description is given of the construction and operation of an automatic version of the coarse batch particle sizer which requires a minimum of operator supervision and which is capable of processing a sample every 4 min.

Jan 1, 1968

By Albert L. Toenges

This paper is the fourth of a series5/ that describes some methods and practices of mining coal mechanically where operations are conducted on more than one shift. Many inquiries have been received regarding methods of extracting pillars with mechanized equipment, and this paper deals primarily with this phase of mechanical mining. Some of the questions that have been asked are:

Jan 1, 1942

The effect of composition on electrical conductivity (resistivity), viscosity and liquidus temperature of the slags encountered in electric smelting of PGM containing suphide concentrates is reviewed, along with the relationsip between slag composition, slag-matte separation and metal losses to slag. Optimization of slag composition at furnace temperature is attempted on the basis of opposite and parabolic trends of the viscosity-conductivity relationships of the slags. The importance of surface tension of slags is emphasized using available and estimated information which are grouped into a useful correlation. These values are coupled with or incorporated into slag viscosity plots to illustrate the correlation between the two factors, which influence slag-matte separation as well as refractory attack. The electrode in the slag-resistance furnace is the central factor in the design and operation of the furnace by its role of conveying the smelting power. The obvious parameters are the size and positioning in the slag bath, which are defined by slag resistively, furnace resistance, cell constant and power input. The flow of heat generated by the electrode current determines the energy distribution and furnace dimensions creating viscosity profiles, which in turn affect flow conditions. Thus the flow of slag and matte are discussed in conjunction with the furnace geometry, stirring action of the electrodes, buoyancy and electromagnetic effects. The action of the electric furnace as a settler is discussed. The rectangular furnace is considered as a channel reactor in this analysis, and the action of the electrodes is described to indicate a balanced settling rate in the area of electrode action. Discussion of the design and production capacity of the electric furnace, with reference too perating current, power input, furnace dimensions and electrode size, are based on considerations derived mainly from slag properties such as its resistively, viscosity and liquidus temperature.

Jan 1, 2004

By D Prior

The Australian mining industry is a significant contributor to the nation’s greenhouse gas (GHG) emissions, and like any industry, it must make efforts to reduce these. Medium- and long-term strategies will include the replacement of diesel engines with alternative energy sources, but what can be done in the short-term to reduce diesel consumption and hence CO2 emissions? Haul trucks are identified as the major contributors of CO2 emissions in the mining fleet and this paper focuses on firstly identifying what drives haul truck emissions and secondly, discussing what is the role of the Fleet Management System (FMS) in reducing these. A key enabler of this is having a robust fuel consumption model within the FMS, and I describe how this may be done. Besides novel approaches to incorporating fuel consumption (CO2) management into truck assignment algorithms, this paper also describes how the FMS can be used to implement and manage procedures and policies to reduce haul truck emissions.

Jun 22, 2022

By David Belknap, Clay Haynes, David Egger

Rehabilitation challenges were met nearly two months ahead of contract schedule for the Design-Build, Fast Track Scituate Aqueduct & Tunnel project in Cranston, Rhode Island. The aqueduct and tunnel were built in the 1920s and consisted of three sections—a 2.3 m diameter reinforced concrete section that extends approximately305 m before it transitions to a horseshoe-shaped 2.3 m wide by 2.1 m high cast-in-place concrete tunnel that continues for approximately 5.3 km until it transitions back to a 2.3 m circular section that extends approximately 1.9 km to the end of this project. Major repairs were required to assure sustained operation of this water supply tunnel.

Jan 1, 2005

By Lawrence K. Requa

The property being worked by the Lewiston dredge of Placer Development (Ltd.) is on the Trinity River in Trinity County, Calif., about 9 miles north of the town of Lewiston (see fig. 1). The nearest rail point is at Rending, Calif., which is exactly 50 miles bar road from the dredge camp. Recently a very good section of State highway has been constructed from Redding to Weaverville, and it is now possible to use this highway for 35 miles of the distance between the dredging property and Redding. The remaining 15 miles, however, are over ordinary dirt road. No trouble is experienced in reaching the property except for a few weeks during the middle of the winter when snowstorms may make travel difficult but not impossible. At present the property consists of about 500 acres of patented land, which extends for about 3 miles along the main Trinity River and Stuart's Pork. It is being worked with one 7-cubic foot, Bucyrus-type dredge, which has an average monthly capacity of about 100,000 cubic yards. To the end of 1931 approximately 10,000,000 cubic yards of gravel had been dredged.

Jan 1, 1932

By Kevin M. Connor, O&apos

This report documents-the process of literature review, site selection, instrument installation, data acquisition, and preliminary data reduction performed to evaluate the influence of rock mass discontinuities on coal mine subsidence. A system of surface, subsurface and mine level instrumentation was installed at the Armco No. 7 Mine in Montcoal, West Virginia where the overburden varied in thickness from 630 to 1040 feet. Survey monuments, borehole pressure cells, full profile borehole inclinometer-extensometers, mine level extensometers, stressmeters and tape extensometer convergence stations were installed to monitor displacements and stress changes. Final design of the instrumentation system was based on: a) review of available information, b) field mapping and analysis of areal photography, c) drilling, and d) borehole geophysics. The report contains the complete graphed data of stress and displacements accompanying the longwall mining of a 4800 ft long by 480 ft wide coal panel.

Jan 1, 1983

By James W. Reil, Douglas A. Anderson

Blast vibration monitoring has generally been regarded as a necessary evil. New instrumentation and computer programs can change this. Rather than the usual trial and error methods to control vibration problems, an integrated, intelligent approach is possible. There is also the possibility of diagnosing problems with the blast vibrations.

Jan 1, 1989

By John B. Sabey, Vernon R. Degner

The industrial coal processing trend toward greater fines production, due to mining techniques and customer requirements for reduced ash and sulphur content in the fine coal product, is the basis for ongoing efforts to improve the performance of the flotation machine. WCO has successfully adapted the principles of the beds Column to a full size machine prototype. Recent plant evaluation tests confirmed the initial promise of this concept by achieving a considerably lower ash product while maintaining the combustible recovery level of conventional flotation machinery. The paper will include a review of the fundamental principles of the beds Column concept, together with a summary of the WEMCO R&D Program from concept evaluation and laboratory testing, through pilot, to full size machine tests. The performance of the WEMCO/Leeds flotation column will be compared to conventional flotation concepts using a flotation "kinetics" approach, which quantifies the floatable and non-floatable specie recovery performance using the Klimpel model as the basis for analysis. The variety of distinct features unique to this concept include a series of barrier rods which are used to advantage, often together with countercurrent reflux water flow, to achieve a significant improvement in product grade. The hydrodynamics associated with the mechanics of "gangue stripping" from the rising "air bubble-floatable specie" matrix will be briefly reviewed.

Jan 1, 1988

By G. D. Andria

Contract J0275007 was to consist of a thorough two-phase statistical analysis of respirable coal mine dust data from USBM Contracts H0232061, H0232060, H0230029, H0230031, H0210050, and H0242013. Consequently, BCR cataloged and assembled relevant data items from these contracts and formulated procedures suitable for the evaluation. The selected procedure was a Multilinear Regression Analysis which related dust concentrations measured in the mine to other mine parameters. Under the first phase, a thorough analysis of the date from USBM Contract No. H0230029 was completed. Primary results from this analysis are as follows: (1) The five variables that significantly affect dust concentrations in the return behind the brattice are the spray system utilized; the distance from the face to the return brattice; the return airflow; the production rate; and the water consumption rate, in that order. These five variables describe about 85 percent of the total variation in the return dust concentration. (2) Results at the miner and jack-setter locations were somewhat less conclusive due to the fact that only 17 percent of the variation in dust at the miner could be resolved and only 48 percent of the variation at the jack-setter location could be explained. The decision of the sponsor was that these initial results revealed as much information as could be expected; thus, per instructions from the USBM, the second phase (analysis of the other five contracts) was abandoned.

Jan 1, 1978