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By W. Joseph Schlitt

The use of plate and frame filter presses for dewatering cement copper at Kennecott' s Bingham Canyon precipitation plant is described. The dewatering process begins by periodically flushing a dilute copper slurry from cone precipitators to a rake thickener. The thickener underflows intermittently to an agitated surge tank which feeds the filter presses with a relatively constant slurry containing 10 to 20% solids. The presses operate with a three-stage cycle; loading, air blowing and discharging. Exothermic reactions occur during the air blow which cause actual drying as well as promoting dewatering via simple filtration. At the completion of the air blow, the presses are discharged onto a conveyor belt which transfers material to the load-out building for shipment to the smelter. An extended investigation was undertaken to relate moisture content in the filter cake to maximum press temperature, acidification of press feed, percent solids in the feed, and percent insol in the copper. Of these, press tempera¬ture and feed pH (3. 5 to 1. 0) have the greatest impact on drying. Because the discharged filter cake is hot and continues to undergo exothermic oxidation, significant drying occurs during subsequent handling so that a product containing 8 to 14% moisture is delivered to the smelter.

Jan 1, 1977

By Sihua Lei, Hong Zhong, Shuai Wang, Yu Gan, Zhanfang Cao

High purity MgO is widely used in various fields as an important magnesiumcompound. The separation of Mg and Ca is of great importance for the preparation of high purity MgO from dolomite. In this study, the key effects of carbonization temperature and nano-calcium carbonate agglomeration on the separation mechanism of calcium and magnesium have been investigated. The results indicated that the reaction in the carbonization process was stepwise. Precise control of the carbonization temperature was essential for the formation of Mg(HCO3)2 due to its low reaction efficiency at lower temperatures or decomposition markedly at higher temperatures. Meanwhile, there was a common-ion effect in solutions containing Mg2+ and Ca2+. Nano-CaCO3 particles were formed during carbonization and agglomerated with the prolongation of static time. A product with a purity of 99.56% MgO and 0.16% CaO was obtained under the optimized conditions: ratio of liquid–solid 30 L/g, carbonization temperature 22–25 °C, carbonization time 1 h, and refining time 4 h. This work has important guiding significance for the preparation of high purity magnesium oxide from dolomite.

Apr 21, 2020

By J. Starwood

Post-super-cycle mining executives must exploit every aspect of the value chain to deliver continued value to stakeholders. Integrating enterprise-wide information technology with value-chain-wide operational technology, known as IT-OT integration, is essential to extracting optimal results from the value chain. Mining companies trail other industries with respect to IT-OT integration across the value chain. Manual data consolidation and value chain optimization using spreadsheets and human intelligence are widespread practices within the industry. Increasing automation with smart devices and controllers means the volume and velocity of data will soon increase beyond human abilities. Enterprise Architecture provides a method for aligning information technology with the business operating model to successfully implement IT-OT integration. A Value Realization Framework (VRF) provides a means for predictable traceable value realization from IT investments and assets. With these principles, frameworks, models, methods, and techniques, mining organizations can accomplish IT-OT integration that provides their executives with a strategic value-chain-aligned platform for sustained value realization over the long term.

Feb 23, 2014

By Richard C. Corson

The objective of blending materials in a bedding pile is to reduce the variation in successive samples taken from the materials to be blended. In designing a bedding and reclaiming operation, several mechanisms are available to effect the reduction of variability, or increase in homogeneity, of the materials. These mechanisms can act before stacking, in the stacking process, in reclaiming and after reclaiming. In evaluating alternative methods of stacking and reclaiming, the potential user must judge each method on the basis of certain criteria; the capital cost of the equipment, the allowable absolute variability of the reclaimed product and the effectiveness of blending. Several stacking and reclaiming methods have been tested using a computer simulation. Based on the results of this program, factors were developed to describe the effectiveness of blending for chevron stacking of discrete materials and preblended materials, bucket wheel reclaiming and drum reclaiming. From these factors, the total effectiveness of a combined stacking and reclaiming system can be determined.

Jan 1, 1985

By R. DasGupta

The dissolution behavior of gold in ammoniacal solutions at 75°C has been investigated. The variables investigated include concentration of lixiviants, pH of the solution and various oxidants. The anodic dissolution of gold was studied in the absence of oxidants using the potentiodynamic polarization technique. The cathodic reaction of oxidants was studied on a platinum electrode. Tafel polarization tests were also performed to determine the dissolution rate. The overall dissolution of gold in ammoniacal solutions was examined using a mixed potential theory. A comparative study on the role of cupric am mine, oxygen, hydrogen peroxide, sodium hypochlorite as oxidants for the dissolution of gold in ammoniacal solutions has been carried out.

Jan 1, 1996

By Ronald M. Hays

The White Pine Copper Division of Copper Range Company is a large copper producer operating an underground mine, mill, and smelter on Michigan's Upper Peninsula. Principal water discharges are from the tailings basin where these discharges are high in dissolved solids because of mine water pumped into the basin. Principal air emissions are from the smelter where SO2 emissions are uncontrolled. Although water discharges and air emissions have not had significant environmental impacts, environmental regulations could require additional control procedures. Because of low copper prices and poor profitability, cost of compliance with possible new environmental regulations could have serious impact on White Pine with no apparent significant beneficial environmental impacts.

Jan 1, 1979

By William T. Barrett

It is said that Thales of Miletus, 600 B.C.,1 was aware of the attraction of lodestone toward iron and highly magnetic minerals. However, the birth of magnetic concentration followed shortly after the invention of the first electromagnet by Sturgeon in 1825. Sturgeon's magnet was described in the annals of electricity.2 The first attempts to concentrate minerals by the use of magnets date back to about 18473 but the first commercial drum-concentrator was apparently invented by R. Cook in 1849. Credit must also be given to the invention of P. Righter's machine in 1867,5 and to the highly successful Wenström separator devised in Sweden in 1883.8 Since the advent of these early separators there have been virtually hundreds of patents granted covering minor modifications of drum-type magnetic separators. The more important advances from a technological viewpoint have been the design of stable power supplies for d.c. magnets, the advent of ceramic permanent magnets which are now replacing electromagnets for the concentration of ferromagnetic minerals, and advances in general magnet and machine configurations.7 One of the problems facing both the designer and the user of magnetic separators is the evaluation of the body forces acting on particles in the magnetic field of the separator. Perhaps the most elegant method of evaluating the body force associated with a drum-type magnetic separator is that recently suggested by W. F. Brown.8 Brown measures the radial component of the field intensity one-half inch from the drum surface and fits a Fourier series in the angle about the drum axis (Figure 1). Once the coefficients of the series are known, it is then possible to calculate [ ]

Jan 1, 1970

By Pei‑liang Xu, Jun Wang, Xi Zhang, Deng‑pan Qiao, Tian‑yu Yang

The surface backfill, serving as the operational platform for continuing mining in upward slicing and filling stopes, is required to possess sufficient strength and thickness. Currently, there are limited model methods for determining the strength and thickness of the surface fill body. By analyzing the mechanical actions on the surface backfill, it is determined that its stability is mainly influenced by the combined effects of normal and tangential uniform loads under full-load conditions of trackless equipment. Assuming a circular contact surface between the tire of the trackless equipment and the surface backfill, and utilizing solutions from elastic mechanics theories such as the Boussinesq and Cerruti solution, the stress and displacement distribution of the surface fill body were obtained. Based on the maximum vertical stress condition, where the surface backfill body undergoes maximum deformation while still in an elastic state, and considering the stress–strain relationship, a model for the strength and thickness of the surface backfill has been established. According to the research findings, the design for the strength and structural parameters of the surface backfill has been developed to meet the full-load operation of the Atlas ST7 scooptram, with a compressive strength of 1.32 MPa and a thickness of 0.5 m. Numerical simulation analysis results indicate that the stress and displacement of the surface backfill align with theoretical analysis results. Practical results from industrial application in the western section of the Dahongshan Copper Mine demonstrate that the designed strength and thickness of the surface backfill meet the operational requirements for trackless equipment, resulting in significant engineering application effects and economic benefits. The research findings hold significant importance for advancing the theory of backfill mining and have high applicability and promotional value for similar mines.

Mar 24, 2024

By R. S. Kalyoncu

Materials demands by the advancing process technologies, desire for higher performance and durability, and improved efficiency in combustion processes, such as applications in heat engines, heat exchanges, and batteries have added to the driving force fueling R&D efforts for the development of components with the combined characteristics of metals and non-metals. These new materials involve refined and specialized microstructures that can lead to improvements in the performance characteristics and durability new technological applications require. Fabrication and sintering methods, once believed to be sufficient, alone, have been found to be inadequate in the manufacture of such advanced components. Realization of the importance of the starting powders has led to efforts to produce materials of ultrahigh purity and ultrafine particle size with very narrow particle size distributions. Such powder characteristics are essential for the fabrication of components with high density and with the desired mechanical, electrical, or magnetic properties called for by the specific application. Novel ultrafine and ultrapure powder preparation techniques are discussed and effects of impurities on the powder characteristics, particle size and morphology, sintering behavior and properties of the finished product are elucidated.

Jan 1, 1992

By Richard H. Follis

Activated carbons used for precious metal recovery from carbon-in­pulp (CIP), carbon-In-leach (CIL) and carbon-in-column (CIC) circuits often become fouled with Inorganic precipitates (i.e., CaCOa, CaS04, SI02), and adsorbed organics (I.e., petroleum distillates from lubricants, dissolution products from wood) (1,2). These contaminants occlude carbon pore structure, such that diffusion controlled adsorption and desorption (elution) of Au(CN)2-and Ag(CN)2· are lmpeded(3,4l. Thus, after only short exposure to the hydrometallurgical environment, the characteristic carbon activity is reduced(5l. By frequently regenerating circuit carbons, activity losses associated with fouling can usually be minimized. Regeneration typically Involves (not necessarily Is this order): 1) elution to remove adsorbed ionic species (e.g., until they are removed from the carbon pore structure, Au(CN)2" and Ag(CN)2-are contaminants )(6l; 2) acid washing with 3-15% (wt/wt) hydro­chloric acid, to dissolve soluble Inorganic precipitates such as CaC03; 3) neutralization and/or water rinsing to remove residual acid; 4) thermal regeneration at 350-650 °C to remove adsorbed and/or pyrolyzed organ­ics; and 5) screening to remove fine carbon particles produced by Impaction and abrasion in the various stages of the hydrometallurgical circuit (i.e., adsorption, elution, and regeneration). The overall process Is purposed to reopen the circuit carbon pore structure, and to maintain the activity and qualities of virgin (new) carbon(7,8l. While most CIP, CIL and CIC operators regenerate circuit carbons, few evaluate the effect of the process on carbon quality in a systematic way. Process control usually Involves Iterating critical regeneration parameters such as: acid concentration; time frames for acid washing and water rinsing; and temperature and residence time for thermal regeneration. Carbon quality control frequently comprises only sporadic activity tests performed on non-representative grab samples dipped from conve­niently accessed carbon storage bins. So, regenerated carbon quality may vary and (at times) be unacceptable for effective hydrometallurglcal circuit operation. To verify the efficacy of the regeneration process and assure accept­able adsorption and elution rates for Au(CN)2· and Ag(CN)2·, operators should systematically assess regenerated circuit carbon quality. This paper, then, suggests methods for effectively assessing circuit carbon quality, Including: carbon sampling procedures; standardized physical and chemical test methods; and criteria and general procedures for comparative adsorption rate (activity) testing. Also, a two tier quality control testing scheme is proposed, and techniques for presenting and interpreting test data are demonstrated.

Jan 1, 1992

By Fernando Jorge Dick

Artificial sulphides have been produced on the surfaces of heavy metal-oxide, minerals at elevated temperatures (1) and these sulphides gave consistently similar flotation characteristics as the respective natural sulphides. In the case of tin, the only natural tin sulphide known is herzembergite (SnS) which is found only in minor quantities, and its flotation behavior is not known. Balberyszki, Dorenfeld, and Carmi reported (2) tests with artificial tin oxide and pure cassiterite treated with hydrogen sulphide at temperatures above 750oc. They confirmed that the product could be floated in acid pulps. However, iron sulphides derived from pyrite, limonite, and hematite which are generally the major impurities in tin bearing ores could not be separated from tin sulphides under the conditions used by previous investigators. As a practical matter, if complex tin ores or complex low grade tin concentrates are to be treated by this process, it is necessary to be able to separate sulphidized cassiterite from other sulphidized minerals in the feed. The major metallic minerals, by weight, in complex tin ores are the iron minerals--pyrite, hematite, limonite, magnetite and pyrrhotite. These minerals become (or remain) sulphidized during the sulphidization process.

Jan 1, 1978

By T. L. Barone, J. R. Patts, L. D. Patts, S. J. Janisko

"Controlling float coal dust in underground coal mines before dispersal into the general airstream can reduce the risk of mine explosions while potentially achieving a more effective and efficient use of rock dust. A prototype flooded-bed scrubber was evaluated for float coal dust control in the return of a continuous miner section. The scrubber was installed inline between the face ventilation tubing and an exhausting auxiliary fan. Airborne and deposited dust mass measurements were collected over three days at set distances from the fan exhaust to assess changes in float coal dust levels in the return due to operation of the scrubber. Mass-based measurements were collected on a per-cut basis and normalized on the basis of per ton mined by the continuous miner. The results show that average float coal dust levels measured under baseline conditions were reduced by more than 90 percent when operating the scrubber. IntroductionAirborne coal dust is a byproduct of coal production, and engineering controls exist to deal with both the respirable dust health hazard as well as the float dust explosion safety hazard. Float coal dust, smaller than 75 µm (0.003 in.) in size, can deposit throughout mine entries and propagate explosions that had been initially fueled by methane gas. The inertization of float coal dust with rock dust helps prevent a potential secondary float coal dust explosion, but a preferable course of action is to significantly reduce the hazard by removing float coal dust from the airstream before it has the opportunity to deposit on the mine’s surfaces.Since 1970, disasters due to explosions in underground coal mines have caused 201 deaths in the U.S. mining industry, including 29 deaths in a single mine explosion in 2010 (Wade, 2010; U.S. Mine Safety and Health Administration, 2015). The U.S. National Institute for Occupational Safety and Health (NIOSH) had initiated a fiveyear research project that aims to investigate methods and technologies to reduce the potential for secondary coal dust explosions by the purposeful capture and/or suppression of float coal dust prior to its deposition on the mine roof, rib and floor (NIOSH, 2013). The project aims to evaluate the efficiency of methods to reduce longwall and belt airway float dust in the general airstream as well as methods to capture it at or near the source. Prioritization is given to longwall sections given the amount of coal produced relative to continuous miner sections, but the research is open to technologies that may be adapted from one method of mining to another."

Dec 1, 2016

By Jessica M. Wempen, William G. Pariseau, Dallan J. Coons, Michael K. McCarter, Erik C. Westman

The abstract discusses the importance of proper pillar sizing in underground mining for safety and efficiency. It highlights the use of theoretical models, geotechnical measurements, and numerical modeling in predicting pillar behavior. The research focuses on using seismic tomography to image stress changes in a yield pillar at a longwall mine as the longwall face approaches. The study aims to compare the stress distribution imaged using tomography with theoretical models, geotechnical measurements, and numerical models.

Mar 18, 2022

By J. A. Mejia

The combination of high-resolution X-ray microtomography (HRXMT) image analysis and Lattice-Boltzmann Method (LBM) simulations has demonstrated the ability to describe real multiphase flow problems in fine coal filtration. The single component multiphase flow He-Chen-Zhang LBM model was used to simulate filtration with actual HRXMT images of pore network structures produced in filtration experiments. The analysis performed on coal, silica, and glass bead filter cakes showed that particle shape and wettability are two of the most important factors in the retention of moisture during filtration.

Feb 23, 2014

By Paul B. Valenti

The Nevada Moly Operation of Anaconda Minerals Co., (a molybdenum/copper ore body) was initiated in 1978, with a contract to Bechtel Civil and Minerals Inc. for construction of a mining and milling facility near Tonopah, NV. Ground was broken on the concentrator portion of the project in August 1979$ with a multi-phased startup of the mill beginning in June 1981. Processing design tonnage of 20 000 t/d (22,000 STPD) was reached in early 1982. Major pitfalls of rapid design and implementation of engineering, construction, and startup are considered. The operation of the concentrator including SAG milling, ball milling, bulk rougher flotation, copper/moly separation, moly regrinding and cleaning, thickening, and product loadout are discussed.

Jan 1, 1983

By Zhongran Dai, Nan Hu, Jianhong Ma, Hui Zhang, Zhihua Zhong, Han Zhou, Feng Li, Yonggen Qiu, Yang Ding, Yingchun Yang, Dexin Ding

In the traditional chlorination roasting-water leaching-solvent extraction process for the extraction of rubidium-bearing ore, Rb leaching from the ore and calcium removing from the leachate are conducted separately, and this results in the complicated process and high energy consumption. In order to integrate the Rb leaching and calcium removing processes, Rb-bearing polymetallic ore was firstly treated by chlorination roasting, it was then leached in a micro-reactor with raffinate, and the calcium ions in the leachate were removed in the reactor as carbonate precipitates by passing CO2 at certain pressure into the reactor. The effects of raffinate alkalinity, CO2 pressure, and CO2 reaction time on Rb leaching rate and calcium removing rate were investigated. The experimental results show that when Rb-bearing polymetallic ore was leached for 90 min by stirring with raffinate with 1.125-mol/L alkalinity, and the pulp was made to react with CO2 at 0.8 MPa for 15 min, the Rb leaching rate and calcium removing rate amounted to 92% and 98.2%, respectively. This integrated process including Rb leaching from Rb-bearing polymetallic ore and calcium removing from leachate could simplify the process for the extraction of Rb-bearing ore and increase its economic benefits.

Sep 27, 2023

By R. F. Pearce

The paper in based on laboratory and pilot plant investigations which led to the development of a series of processes for production of high purity metals from nickel-copper-cobalt mattes of a wide range of composition. The selection of ammonia pressure leaching or acid pressure leaching for various mattes is discussed. This is followed by discussion of various methods for leach solution purification and metal separation. The metals of high purity are produced by reduction with hydrogen from purified solutions. Examples are given of complete flowsheets for a number of mattes. Drawing upon those examples, general principles for the selection of the most suitable treatment process for particular material are outlined. Under certain circumstances, those processes may replace part of the pyrometallurgical treatment and all of the electrolytic refining steps which are customary in the treatment of nickel-copper-cobalt mattes.

Jan 1, 1959

By Ali Jaberi Zamharir, Abolfazl Shoghian‐Alanaghi, Hossein Aghajani, Arvin Taghizadeh Tabrizi

In this study, the leaching rate of molybdenite concentrate was evaluated in sulfuric medium, and the influence of the diverse oxidants including hydrogen peroxide, manganese oxide, copper sulfate on the leaching rate was studied. Also, the effect of the addition of the ethylene glycol to the hydrogen peroxide was studied and results showed that with the addition of ethylene glycol, the leaching rate is increased 55% from 41% up to 80.3%. The optimum condition is achieved as 0.7 M of H2SO4, 4.4 M of H2O2, and 3.5 M of EG at 30 °C within 4 h of leaching time and 500 rpm. Also, inserting the oxygen with the pressure of 6 bar to the leaching autoclave, the leaching rate is increased more up to 86.4%. Finally, the leaching process was studied kinetically and the determined mode of controlling factor was specified based on the activation energy which equals 46.252 kJ/mole indicating the chemical reaction mode.

Jun 5, 2022

By Richard E. Gray

Virtually all structures show some signs of distress due to deterioration of the building components, to changed loads, or to changed support conditions. Changed support conditions result from ground movements. In mining regions many cases of structural distress are attributed to mining without considering alternative causes. This is particularly true of coal mining since it occurs under extensive areas. Coal mining is estimated to have already undermined more than eight million acres and may eventually undermine 40 million acres in the United States (HRB Singer, Inc., 1977). Other nonmetal and metal underground mines impact much smaller areas. Although it is sometimes difficult, even with careful study, to identify the actual cause of damage, persons responsible for underground coal mining should at least be aware of possible causes of building stress other than mine subsidence. This paper presents information on distress to structures and briefly reviews a number of causes of ground movements other than subsidence: Mass movements, dissolution, erosion, frost action, shrinking and swelling, yield into excavations and compressibility

Jan 1, 1986

By A. N. Pritchard

The development of vibrating screens over the last century has seen many variations to suit the exacting requirements of industry. Indeed, as each year passes, industry has presented the challenge to screen manufacturers of supplying larger machines than those used in the past and the question is often posed - what is the maximum limit? Not only must size or screen area be considered but excellence of performance in terms of screening efficiency must be maintained or maximized.

Jan 1, 1983