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By A. McLean, A. Hue, K. Le, Y. D. Yang, P. Wu

While the treatment of relatively inexpensive ferrosilicon alloys is a potential refining route in order to generate solar grade silicon, phosphorus is one of the more difficult impurities to remove by conventional processing. In this project, the use of an electromagnetic levitation technique was used to investigate the dephosphorization of ferrosilicon alloy droplets exposed for various times and temperatures to a hydrogen-argon gas mixture. It was found that approximately 40% of the phosphorus was removed from an 85%Si-15%Fe alloy after 20 minutes exposure at approximately 1673K, to a gas mixture containing 48.5% hydrogen. Further dephosphorization is expected with longer reaction times. The effect of increasing temperature was found to be insignificant, although processing at lower temperatures is not only economically advantageous, it also decreases evaporative silicon losses, thus resulting in a more efficient process.

Jan 1, 2015

By R. Lasmanis

"Washington State's diverse geological setting is reflected by its several types of porphyry Cu-Mo deposits. All are associated with calc-alkaline intrusions, and they range in age from Jurassic to Miocene.The largest is the Mount Tolman Mo-Cu deposit located in the Omineca Belt. It contains 2.18 billion tonnes of material averaging 0.093% MoS2 and 0.09% Cu. There are intermediate-size Mesozoic deposits in the Intermontane Belt. The Cascade volcanic arc hosts small- to medium-Tertiary deposits. Among these, of particular interest is the Sunrise breccia pipe, which has been explored over a vertical distance of 1000 m. It contains reserves of 64.6 million tonnes averaging 0.319% Cu and 0.071% MoS2 with significant tungsten values. The Glacier Peak deposits have potential resources of 1.7 billion tonnes averaging 0.334% Cu and more than 0.015% MoS2 and also contain tungsten. The Margaret deposit can be classified as a porphyry Cu-Au type; it has reserves of 200 million tonnes averaging 0.434% Cu, 0.0175% MoS2> 0.27 g!t Au and 1.92 g!t Ag. Drill intercepts of the North Fork deposit also show significant gold values.Mineralization and hydrothermal alteration of these deposits are typical of porphyry deposits, although some differences can be noted. The Mount Tolman molybdenum deposit contains topaz alteration zones and is transitional between a plutonic type and a Climax-type molybdenum system. Other deposits, such as the Kelsey, Mazama, North Fork, and Margaret, are low-sulphide systems that contain significant amounts of magnetite."

Jan 1, 1995

By Frank Arthur Forward

FRANK ARTHUR FORWARD was born in Ottawa and attended the University of Toronto, where he received a B.A.Sc. in chemical engineering in 1924. From 1924 to 1929, he was a smelter operator and research metallurgist with the Consolidated Mining and Smelting Company of Canada Ltd. (Cominco) at Trail, B.C. Moving to Australia in 1929, he was assistant smelter superintendent, Mount Isa Mines Ltd., Queensland, until 1934, when he returned to Canada, spend-ing one year as metallurgist with B.C.

Jan 1, 1970

In the present work, the effect of pH, non-ionic polyacrylamide flocculant and anionic polyphosphate on rheology and settling behaviour of colloidal TiO2 suspensions (15 ? 50 wt% solid) is investigated. Maximum particle aggregation, reflecting in the highest suspension settling rate and maximum shear yield stress was achieved at pH 7.2, the isoelectric point (iep), consistent with DLVO expectation. However, the maximum aggregation condition at the iep also resulted in the poorest suspension consolidation behaviour. Significantly enhanced consolidation was achieved for a more dispersed suspension at pH values away from the iep but at reduced settling rate. Thus, when pH alone is used to control conditions which facilitate strong interparticle attraction, a high settling behaviour which is not conducive to compact consolidation results. Improved suspension consolidation may be achieved at the iep via anionic polyphosphate addition which leads to attenuation of the strongly attractive van der Waals forces and emergence of "soft" repulsion due to weak inter-particle electro-steric forces. The weak repulsion act to lubricate particles involved in the hydrodynamic interactions which controls the compressibility of the sediment bed, allowing a compact consolidation of solids to be obtained. Alternatively, non-ionic polyacrylamide homo-polymer (Magnafloc 333) was fairly effective in flocculating titanium dioxide suspensions leading to high settling rate and acceptable pulp consolidation at the iep.

Jan 1, 2006

By Henrik Saxén, Mikko Helle

The operation of hot stoves used for preheating the blast in the ironmaking blast furnace has a strong effect on the consumption of reductants, economic performance of and CO2 emissions from the steelmaking site. Generally, it is recommended to maintain as high blast temperature as possible, because this minimizes the rate of reductants in the blast furnace. The blast temperature is affected in a complex way by the time periods of heating and cooling of the stoves, and by the amount of gas combusted in the stoves. Furthermore, as the hot stoves show degraded performance with age, it is a non-trivial task to select optimal operation parameters for the stoves. The paper addresses this computationally by applying a one-dimensional heat-transfer model of the hot stoves for optimization of the performance of the system. The complexity and strong coupling of the decision variables is demonstrated by numerical examples, where the blast temperature is maximized under different constraints.

Jan 1, 2015

By Claude Bourgoin

"The Copra massive sulphide deposit occurs as a continuous slab of ore dipping at approximately 40 degrees within a sericite schist formation. The orebody has been delineated over a distance of more than 5,000 feet down dip. This paper is mainly concerned with the mining procedure, and particular reference will be made to the use of steel mill holes and hydraulic roof supports. The gravel backfill line, which is operated both by gravity and hydraulically, is described. The paper mentions some of the operational problems, discusses the feasibility of longwall mining and presents the information obtained from stope testing."

Jan 1, 1966

By M. Sagedahl

The off gas from a smelter is cooled and dust removed in an electrostatic precipitator before approximately 95% of the sulphur dioxide (S02) is converted to sulfuric acid. However, the tail gas may need to be polished to remove the rest S02 to meet demands. A flue gas desulphurization (FGD) system, as usually applied to S02 removal on coal and oil fired Power Station, is suitable for polishing tail gases from copper smelters. The ALSTOM Seawater FGD process makes use of the alkalinity in the seawater to absorb and neutralize S02. Before being returned to the sea, the seawater is treated to comply with environmental regulations. As the ALSTOM Seawater FGD process uses no reagent and produces no byproduct, it is extremely cost-effective for coastal installations. The first SWFGD plant started operation in 1968. Over 60 of these units have been installed worldwide. The ALSTOM Seawater FGD process removes S02 from flue gas flows corresponding to a total of 70,000,000 Nm3 /h. Suitable for thermal power stations, smelters and oil refineries, ALSTOM Seawater FGD plants efficiently treats flue gases in the range of 300,000 Nm3/h to 2, 700,000 Nm3 /h per FGD plant, containing 20 - 6,500 ppm of S02.

Jan 1, 2007

By T. R. Kostecki, K. V. Jessu

"Roof bolts are subjected to axial stresses, shear stresses, or both. Axial and shear stresses were compared between roof bolts machined with two and three slots. Shear stresses perpendicular to and at an angle to the shear planes were evaluated by analyzing a three-slot instrumented roof bolt, performing laboratory tests on two- and three-slot roof bolts, and conducting in-situ test analyses. Threeslot bolts appear to provide a complete bending strain profile, requiring no prior knowledge of the estimated shear-plane orientation. Minimum displacements occur in roof bolts installed perpendicular to rather than at an angle to the shear planes.RÉSUMÉ Les boulons d’ancrage dans le toit d’une mine sont sujets à des contraintes axiales, des contraintes de cisaillement ou les deux. On a comparé les contraintes axiales et de cisaillement de boulons d’ancrage usinés avec deux ou trois fentes. Les contraintes de cisaillement perpendiculaires et à angle aux plans de cisaillement ont été évaluées en analysant un boulon d’ancrage de toit à trois fentes, en effectuant des essais en laboratoire sur des boulons d’ancrage de toit à deux et à trois fentes et en effectuant des analyses de tests in situ. Les boulons à trois fentes semblent fournir un profil complet de résistance aux contraintes de flexion, sans avoir besoin de connaître l’orientation estimée du plan de cisaillement. Des déplacements minimums ont lieu dans les boulons d’ancrage de toit installés perpendiculairement, plutôt qu’à un angle, aux plans de cisaillement."

Jan 1, 2016

By M. H. MacLeod

"IntroductionTHE ORE PASS raise system at the H.B. mine as contracted by the Patrick Harrison Company consisted of two raises 6 ft. by 10 ft. in section •at 60 degrees to the horizontal. No. 88-88 raise, the longer of the two, was a straight raise 690 feet long, with access only from the bottom. In addition, this raise had two branch knuckle-backs only one of which was driven by. the Patrick Harrison Company. The other, known as 88-89 raise, was 540 feet long with knuckle-backs at 280 feet and 410 feet. Its access, also, was from the bottom (see Figure 1)."

Jan 1, 1954

By E. J. Wasp, T. L. Thompson, T. C. Aude

The paper will deal with some of the more important technical aspects of slurry pipelines as they apply to the mineral field. In addition, the use of these technical concepts in arriving at realistic economic figures will be discussed.

Jan 1, 1970

"In many gold deposits, a reasonable amount of the gold that remains in the cyanide leach tailing is associated with pyrite. Some gold plants have found it economical to incorporate gravity circuits on the cyanide leach tailing to recover the gold bearing pyrite before subjecting it to fine grinding, then recycling the ground pyrite back to the cyanide leach circuit. For low grade gold deposits the loss of gold bearing pyrite is exacerbated as the broader process economics normally favour a coarse grind (> 150 ?m). An option that has received attention over the last decade is to recover the gold bearing sulphides in the milling circuit by gravity, similar to the widely-practiced gravity recovery of free liberated gold. The modelling and simulation of a gravity gold circuit in a milling flowsheet is relatively simple compared with a gold bearing pyrite circuit, as the recycle advantages and breakage functions for gold and pyrite are quite different. This current work represents an attempt to simulate the gravity recovery of gold bearing sulphides in a milling circuit that also incorporates fine grinding, using relatively simple simulation models. The simulation results are further explored with reference to the economics of this type of circuit.INTRODUCTION It is well known that gold is associated with pyrite in most sulphide gold deposits and that the amount of gold associated with pyrite will vary from deposit to deposit. Most of the gold associated with pyrite is liberated in the grinding circuit during the processing of a gold ore. However, some gold remains occluded in the pyrite and is lost in the final leach tailings. Little information is available in the literature on methods to enhance gold liberation from pyrite by specifically removing pyrite, either in the grinding circuit or from the final tailings stream, and grinding it finer. One of the earliest record of this approach is described by King (King, 1949) where pyrite present in Witwatersrand gold ores was recovered by circular jigs and Johnson barrels followed by fine grinding of the concentrate prior to cyanide leaching. Dominy et al., 1970, provides information on the use of Yuba jigs to recover pyrite from the discharge end of ball mills. Again, the jig concentrate was ground to a fine particle size before cyanide leaching to recover the liberated gold. Unfortunately, no information is provided in these articles on the additional gold recovery from implementing these circuits in a flowsheet. Martins et al., 1993, provides details of a gravity circuit using Reichert cones and spirals to recover gold bearing pyrite from a cyanide leach tailings followed by fine grinding of the pyrite concentrate in a Tower mill. The ground concentrate returned to the front end of the already installed leach circuit. Overall recoveries were increased by some 2% to 4% depending on the amount of gold and pyrite in the plant feed."

Jan 1, 2017

By V. G. Papangelakis, M. Cheung, M. Dry

The high pressure acid leaching of laterite was modelled and simulated using a combination of two commercially available software packages, namely Aspen Plus 11.1 and the OLI Stream Analyzer. New kinetic parameters for the acid-controlled metal dissolution and precipitation reactions at temperature were first determined from previous experimental data on the leaching of limonite. A grain model with cylindrical pellets was used to model the solid-liquid dissolution reactions. Precipitation reactions were modeled via aqueous equilibrium chemistry. A dedicated thermodynamic database previously developed at the University of Toronto was used in conjunction with the OLI software to model the solution chemistry and calculate the concentration of hydrogen ions in solution at the leaching temperature. Mass balances were handled by Aspen Plus. The simulation gave good predictions of nickel dissolution under industrial and laboratory conditions, for the dissolution of limonite and limonite/saprolite blends. Computational

Jan 1, 2005

By A. Banerjee, J. P. Weiler, J. Jekl, J. T. Wood, R. Berkmortel

"The work presented here is part of an ongoing project designed to develop predictive capabilities of the local mechanical properties, and thus, structural behaviour of a thin-walled high-pressure die-cast AM60B magnesium alloy component. This work focuses on developing correlations between process parameters and local microstructure. Numerical simulations of the die filling and solidification behaviour of the AM60B component were used to estimate local process parameters such as solidification rate, temperature gradient, filling velocity, etc. These estimated parameters were used to establish semiempirical correlations with measured VALUES (of the local microstructure measured in regions throughout the component of different solidification conditions. INTRODUCTIONHigh-pressure die-cast magnesium alloys are experiencing increasing use in structural automotive components. A strength-to-weight ratio comparable to steels and its ease of castability allow for these alloys to be utilized in such capacities as instrument panel beams, seat and door frames, and engine cradles, among others (Gjestland and Westengen, 2007). However, the current use of these alloys is limited due to variations in local mechanical properties. These local property variations restrict part designers to assume lower than actual properties, resulting in larger sections, thus diminishing the light-weighting advantages of magnesium alloys. If these local property variations could be predicted, part designers would be able to optimize die-cast magnesium alloy components and fully take advantage of the light-weighting capacity of these materials.The work presented here is part of an ongoing project aimed at developing predictive capabilities of the local mechanical properties, and bulk mechanical performance, from variations in local microstructure, and ultimately from local process parameters in die-cast magnesium alloys. This project, unique in its nature, is based upon the results determined from fifty sequentially cast AM60B magnesium alloy instrument panel beams provided by Meridian Lightweight Technologies (shown in Figure 1)."

Jan 1, 2012

By Gurupraveen Ramanathan

Shallow-dipping orebodies (45°–60° dip) present significant challenges for underground longhole stoping, particularly due to limited gravity flow, drill misalignment near the footwall, increased potential for dilution from hanging wall overbreak, and deviation from drill string sagging at shallow angles. These geometrical and operational constraints often lead to unblasted ore wedges and excessive overbreak when standard practices are applied. This study develops a structured, data-driven framework to optimize longhole stoping in such conditions by integrating five key focus areas: (1) mining method selection, (2) stope and drift design, (3) drill and blast optimization, (4) equipment selection, and (5) performance evaluation. The suitability of longitudinal longhole stoping was validated for narrow vein geometries using orebody analytics and prior case studies. Geometric modeling was employed to determine optimal stope height (15–20 m) and stope width (1.5–2.5 m), with drift widths adjusted based on orebody dip to maintain drill access and minimize unbroken ore. Drill and blast design emphasized sequential blasting over multi-ring methods to improve void control, reduce wall damage, and enhance fragmentation. Specific burden and spacing guidelines (e.g., 1.8–2.3 m burden; 2.5–3.0 m spacing) were applied based on stope width and dip angle, and patterns were selected based on geometry—dice-5 for narrow stopes, and 3-hole rows for wider stopes. Drill rigs—including top hammer and ITH models from Sandvik, Epiroc, Boart Longyear and CMAC-Thyssen—were evaluated for compatibility with drift dimensions and alignment accuracy. Equipment was matched based on dip, drift width, and the ability to access the footwall at shallow angles. Sensitivity analysis quantified how changes in geometry, drilling accuracy, and blast design affect ore recovery, dilution, and operating cash flow. Results show that tailored drift and stope geometries, combined with proper blasting and rig selection, can boost ore recovery to over 95% and reduce dilution to below 5% in optimal conditions. This methodology offers a practical and economically optimized solution for shallow-dip mining scenarios.

May 4, 2025

By F. J. Hrach, S. A. Gasiorowski, J. D. Bittner

"Separation Technologies, LLC (ST) has developed a processing system based on triboelectric charging and electrostatic separation that provides the mineral processing industry a means to beneficiate fine materials with an entirely dry technology. In contrast to the other available electrostatic separation processes that are typically limited to particles greater than 75 µm in size, the ST belt separator is ideally suited for separation of very fine (<1 µm) to moderately coarse (500 µm) materials with very high throughputs.. The technology has been also successfully applied to the beneficiation of a variety of minerals including calcium carbonates, talc, and potash. TECHNOLOGY OVERVIEWThe ST separator utilizes electrical charge differences between materials produced by surface contact or triboelectric charging. When two materials are in contact, material with a higher affinity for electrons gains electrons and thus charges negative, while material with lower electron affinity charges positive. This contact exchange of charge is universally observed for all materials, at times causing electrostatic nuisances that are a problem in some industries. Electron affinity is dependent on the chemical composition of the particle surface and will result in substantial differential charging of materials in a mixture of discrete particles of different composition.In the ST separator (Figures 1 and 2), material is fed into the thin gap 0.9 – 1.5 cm (0.35 -0.6 in.) between two parallel planar electrodes. The particles are triboelectrically charged by interparticle contact. For example, in the case of coal combustion fly ash, a mixture of carbon particles and mineral particles, the positively charged carbon and the negatively charged mineral are attracted to opposite electrodes. The particles are then swept up by a continuous moving open-mesh belt and conveyed in opposite directions. The belt moves the particles adjacent to each electrode toward opposite ends of the separator. The electric field need only move the particles a tiny fraction of a centimeter to move a particle from a left-moving to a right-moving stream. The counter current flow of the separating particles and continual triboelectric charging by carbon-mineral collisions provides for a multistage separation and results in excellent purity and recovery in a single-pass unit. The high belt speed also enables very high throughputs, up to 40 tonnes per hour on a single separator. By controlling various process parameters, such as belt speed, feed point, electrode gap and feed rate, the ST process produces low carbon fly ash at carbon contents of 2 % ± 0.5% from feed fly ashes ranging in carbon from 4% to over 30%."

Jan 1, 2012

By W. W. Rudolph, L. N. Trevani, P. R. Tremaine

UV-visible spectroscopy, Raman spectroscopy, and vibrating tube densimetry have been used in our laboratory to determine equilibrium constants of aqueous species at temperatures as high as 325 °C. The UV-visible and Raman spectra of solutions containing metal complexes and ionized acids or bases can be used to yield formation constants by applying curve fitting methods to resolve the contribution of each species. Colorimetric pH indicators identified by Johnston and coworkers at the University of Texas (Austin) provide an alternative means of determining ionization constants and the pH of complex mixtures. High precision density measurements over the same range yield standard partial molar volumes, which are key parameters for "equations of state" for aqueous species. Examples are given for the copper-ammonia system, simple carboxylic acids, and the iron-sulphate system.

Jan 1, 2004

By C. E. Dowker

"IntroductionMechanization underground at the Buffalo Ankerite mine in Deloro township, Porcupine district, had reached a high level by 1944, both in equipment available, and in the use of this equipment, for all stoping operations. Power feed leyners and the latest type of stopers for drilling, slushers for moving ore and fill, and tugger hoists for all servicing, did much to halt rising stope costs, and in some cases decreased them. On the other hand, little beyond the use of mucking machines and power feed leyners had been adopted in the effort to reduce level development costs, or to increase the advance per man-shift.Faced with ever increasing level development costs, caused by rising prices of equipment and supplies, coupled with increasing wage demands for less physical effort, it was realized that more mechanization of development work was essential. The objectives of such further mechanization were:(1) Decreased development costs(2) Increased footage per man-shift(3) Less physical effort by development crews, with greater take-home pay (4) A more satisfied and stable labour force"

Jan 1, 1950

By J. C. Loretto, H. A. Simons

The paper discusses how, in the routine testing of ores, insufficient communication between the laboratory and the design personnel can lead to misunderstanding or misinterpretation of test results and consequent design errors. A number of examples are given together with suggested modified interpretations and the resulting dollar savings indicated by these new interpretations.

Jan 1, 1972

By George P. Demopoulos, Yan Zeng, Zhibao Li

Precipitated silica is marketed with a rising demand as reinforcing filler in the rubber industry and as a potential raw material for the synthesis of lithium-ion battery electrodes. Due to an awareness of the environmental impact of the existing processes for the production of precipitated silica, a green and sustainable process was proposed by using sodium bicarbonate (NaHCO3) as an alternative to sulfuric or hydrochloric acid in the precipitation reaction with sodium silicates. The use of NaHCO3 allows for better control of the supersaturation and pH to form silica with desired quality. Additionally, Na2CO3 solution as the process by-product is recyclable because it could be recovered to produce NaHCO3 by absorbing CO2. The solubility of sodium metasilicate nonahydrate (Na2SiO3·9H2O) in the Na-CO3-HCO3-OH-H2O system was measured using a dynamic method in the temperature range from 288.15 to 308.15 K. It is found that the solubility of Na2SiO3·9H2O decreases with increasing concentration of either Na2CO3 or NaOH over the investigated concentration range. With the aid of the OLI platform, a chemical model for the Na2SiO3-Na-CO3-HCO3-OH system was established with newly obtained interaction parameters of the Bromley-Zemaitis model by regression of experimental solubility data. The new model predicted the solubility of Na2SiO3·9H2O in multi-component systems with good agreement and was used to conduct a preliminary feasibility study of the new process.

Jan 1, 2015

By Jack F. McQuat, Ross D. Lawrence

"Most geologists and mining engineers, in the course of their professional careers, frequently become involved with the appraisal of metalliferous mineral deposits and develop a familiarity with and standard approach to the evaluation of these deposits. When the same individuals approach the industrial mineral field, however, their usual approach pattern can be rudely disturbed.This paper highlights the difference in appraisal approach and outlines the factors common to both but which have entirely different emphasis. These comprise geological appraisal, analytical requirements, the importance of transportation, marketing requirements and standards, including appropriate allowances for product development, and marketing penetration.Out of these ""different"" considerations, however, a pat-tern or standard approach emerges which is as common to the industrial mineral field as that used either consciously or subconsciously in the metallic field.The paper reviews the different factors and points of emphasis and offers an outline of the common pattern of appraisal for industrial minerals."

Jan 1, 1971