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By H. Arima

The Akita Zinc Company is the only refinery which produces hematite from the iron content in the zinc leach residue. The Akita Hematite Process consists of five stages, which are SO2 pressure leaching, the first neutralization stage, the de-arsenic process, the second neutralization stage and pressure hematite precipitation. In order to strengthen its cost competitiveness and stabilize its operation, the Akita Hematite Process has been modified continuously. Most recently, two process modifications were carried out. The first was an improved ability to maintain a lower arsenic concentration in the de-arsenic process, and the second was an increased throughput in the hematite precipitation autoclave. The details of these recent changes in the Akita Hematite Process are presented in this paper.

Jan 1, 2006

By J. A. Finch

The metallurgical performance of a flotation cell is strongly influenced by the features of the bubble population, characterized by the gas dispersion properties, a collective term including bubble size, superficial gas velocity and gas holdup. It is required that gas be well distributed throughout the cell. Gas distribution is estimated here by simultaneous measurement of gas velocity (Jg) at different distances from the center (radial Jg mapping). This communication describes a technique to perform radial Jg mapping together with fundamentals for the interpretation of the data.

Jan 1, 2009

By A. K. Verma

This paper provides a brief overview of evolution of deformations, stresses, and pore pressures due to different excavation stages during construction of an URL. Excavation of a rockmass develops a damage zone of finite width around the excavated zone which is associated with changes in permeability and which affects the fluid flow mechanism. In this study, a coupled hydromechanical (HM) analysis has been conducted for a water saturated porous rock mass which has been created by sequential excavation and backfill of vertical disposal pit of an URL. For this purpose, an Atomic Energy of Canada Limited?s in-floor concept for a deep geologic repository suitable for Indian conditions has been used. Changes in rock deformations, stresses, strains and mechanically induced pore pressure in an undrained condition, during excavation, as well as those caused by mechanically induced rock deformations after backfill of the disposal pit, have been modeled. A three-dimensional finite difference tool FLAC3D has been used for the analysis.

Jun 1, 2012

By J. B. Yianatos, F. A. Contreras

Mineral carrying rates across the pulp-froth interface in the range of 1.4-3.2 tph/m2 and bubble surface coverages between 7 and 22 %, have been determined in large rougher flotation cells operated under normal conditions. To evaluate these variables, measurements of bubble size distribution, bubble load and size distribution of particles collected by true flotation, were performed at different concentrators. A model for estimating the bubble surface coverage at the pulp-froth interface level as a function of bubble load, Sauter mean bubble diameter and particle size distribution of the mineral collected by true flotation, was developed. Bubble loadings in the range 24-70 kg/m3, bubble sizes between 1.5 and 3.2 mm and superficial gas rates between 1.2 and 2.0 emfs, were measured in copper rougher flotation cells under normal operating conditions. Estimated bubble surface area fluxes were in the range 31 to 62 cm2/s/cm2- Results of carrying rates and bubble surface coverage, at the pulp-froth interface, were significantly lower than the maximum carrying rate for the collection zone, indicating that in this case is difficult to achieve maximum carrying rate at the pulp-froth interface level. The main constraints regarding carrying capacity limitations are then related to the froth transport characteristics (i.e. cell design, froth residence time, froth stability, froth recovery). Advances in Mineral Processing Science and Technology Proceedings of the 48th Annual Conference of Metallurgists ofCIM Sudbury, Ontario, Canada Edited by

Jan 1, 2009

By J. Lu, M. Mohammadi, C. Pelletier, B. Wassink

Chemical reduction of selenate by chromous ions is proposed as a novel method to remove selenate from sulfate-bearing solutions Chromous ions were generated by electrochemical reduction of chromic ions using an electrochemical cell. The investigation was conducted in sulfate medium and under various concentrations of chromous ions (0.0062 to 0.05M), pH 1 to 2.2 and temperature 10 to 60°C. Selenate ions were rapidly reduced by chromous ions to hydrogen selenide. The overall reaction at a chromous/selenate molar ratio of 8 or higher can be expressed by the following reaction. At an initial chromous/selenate molar ratio below 8, the products are hydrogen selenide and elemental selenium. At a lower chromous/selenate molar ratio and pH, more elemental selenium and less hydrogen selenide are produced. The reduction kinetics is controlled by both chromous ion and hydrogen ions concentrations. The reaction rate is first order with respect to selenate, hydrogen ion and chromous ion concentrations. It was found that the selenate reduction rate with chromous is independent of the concentration of sulfate present in the solution. The general rate equation was proposed and the rate constant was calculated as k= 0.38 M-2s-1. An activation energy of 58.7 kJ/mol was obtained in the temperature range from 10 to 50°C. Nearly 100% of selenate can be reduced to H2Se from solution containing 17 ppm selenate in less than 30 minutes at pH 2.2 and 60°C. Various strategies have been tested to remove the produced H2Se from solution. INTRODUCTION Selenium in nature is mostly associated with metal sulfide minerals such as copper, iron, zinc, and lead sulfides (Zingaro & Cooper, 1974). The extraction of metals from ores has the potential for selenium contamination of ground and surface water which can pose an environmental and health concern. Therefore, selenium contamination in the receiving environment is a key issue for many industries (specifically copper industry) and the treatment of wastewater contaminated with selenium is a growing challenge. The effective removal of selenium from contaminated water is very important to support sustainability in the copper industry and the other industries with selenium pollution issues.

Jan 1, 2019

By E. C. Goodhue, R. D. Coleman, I. E. Puddington, A. F. Sirianni

Iron ore samples containing apatite are fractionated to acceptable products by spherical agglomeration methods. The phosphorus is upgraded by a factor of 10 at an elevated pH. High-grade iron products are obtained in good yields from the tailings in a second step of the operation. The grade of the phosphorus separated appears to reach a maximum at about pH = 10; recovery of iron decreases below about pH = 4. Both the recovery and grade of iron are found to be reduced sharply above about pH = 8.

Jan 1, 1968

By M. Kuyumcu

With annual production of almost 3.5 million metric tonnes of K20, former East Germany (GDR) was the world?s third-largest producer of potash, ranking behind only the Soviet Union and Canada. More than 80 % of production was intended for export to earn urgently needed hard currency. For this reason, beginning in the 1970s, East Germany began to mine unprofitable hard-salt sources and carnallitite fields, which are geomechanically problematic. In the course of restructuring from a centrally planned to a market economy after German reunification, only two of the nine existing potash mines were classified as economically viable for privatization. All six potash mines in the South Harz Region were closed between 1991 and 1993. The orderly safekeeping of these potash and other decommissioned ore mines and the rededication of mining areas were assigned in 1992 to a German state-owned company GVV founded especially for this purpose. Elaboration in the present documentation covers the local necessity of the type and extent of filling and safeguarding measures. As a result of the remedial measures taken, it was possible to prevent the collapse of cavities and damage to surface facilities. This documentation describes the safeguarding successes to date, with appreciable reduction and stabilization of surface settlement and with significant lessening of seismic events. Also presented are concepts updated to the state of the art for safeguarding of numerous potash mining shafts for long-term effectiveness in separation of the workings and watercourse levels in the cap rock. In the course of 100 years of production, six mining dumps resulted with a total volume of approximately 170 million m3. They consist of up to 95 % of water-soluble salts. Every year, precipitation dissolves up to 500,000 tonnes of this salt, which enters as a highly concentrated solution into watercourses and ground water. Explanation follows of measures for minimization of environmental pollution by covering of dumps and controlled drainage of alkaline solutions from the dumps. Finally, presentation is made of the results of the successful work until now by GVV for reuse of decommissioned mining sites with settlement of new companies for creation of additional jobs and for revitalization of the monostructured South Harz Potash Mining Region.

Aug 1, 2013

By Norman A. M Macleod

FOR the past seven years, all flotation at the Britannia mill has been done in Forrester Air-Lift cells. Prior to 1931, the roughing and part of the cleaning operation had been performed in four 21-cell and two 14-cell M.S. machines. The resulting economies in reagent, power, maintenance, and general operating costs, and the increased recovery, more than justified the exclusive use of the Forrester machine. About three years ago, the possibility of still further improving the efficiency of the flotation section was the subject of considerable discussion and experiment. Arising from these experiments, tests were made of the practicability of using a cell of greater depth than that of any pneumatic or mechanically-agitated machine in common use. Cells were constructed with depths of 7 .5 feet, 10 feet, and 15 feet, and, in all cases, a very definite improvement in operation was indicated. The cell now being used in the mill treats from 5,500 to 6,200 tons of dry feed per day. It is 100 ft. long by 5 ft. wide by 8 ft. deep, and has replaced a total length of over 500 feet of standard Forrester machine. The choice of a depth of 8 feet was governed by the type of blower which was available-in this case, a Roots-Connersville blower, driven by a synchronous motor and delivering 6,000 c.f.m. of free air at 4.0 pounds per square inch. At the Chelan Division of the Howe Sound Company, where a new mill was recently built, all flotation is carried on in cells 10 feet deep, with good results.

Jan 1, 1938

By J. P. Harrison, R. Roostaei

"In this paper we investigate the consequences of using conventional triaxial peak strength criteria in the polyaxial stress conditions that occur around the end of a long circular underground opening. A series of 3d boundary element analyses were performed using Examine3D to determine the stresses induced around the tunnel in different in-situ stress conditions. To discuss the applicability of a triaxial strength criterion in failure prediction, strength factors were computed for both the Ottosen polyaxial strength criterion and the triaxial Hoek-Brown criterion. Assuming that the Ottosen criterion is an accurate indicator of strength factor, the discrepancy from this value due to the Hoek-Brown criterion is the error in prediction.In order to simultaneously show the error in prediction and actual strength factor, a quantitative bivariate colour scheme is used to visualize the results. This allows rapid identification of regions with large error, and where either unsafe or overly conservative conditions occur. We show how the inappropriate use of triaxial criteria rather than polyaxial criteria leads to an under- or over-estimation of strength factor, and can result in uneconomic or unsafe design. Extending the analysis to different in situ stress regimes shows how the in situ stress conditions affect the assessment."

Jan 1, 2015

By J. M. Harrison

"The Nor-Acme gold mine is near the shore of Snow lake, northern Manitoba, about 75 miles east of Flin Flon. The claims that form the nucleus of the present property were staked in 1927 by C. R. Parres, but it was not until 1941 that diamond drilling disclosed the potentialities of the deposit. In that year a large-scale drilling programme was begun under the direction of F. Ebbutt, of the Howe Sound Exploration and Development Company. Two orebodies were outlined containing about 5,000,000 tons of ore assaying $5.25 in gold per ton. In August, 1945, construction of the mining plant was begun.All information and interpretations contained in the following brief description of the deposit were obtained from surface mapping.GEOLOGYThe ore lies at the contact between a coarse, basic, pyroclastic rock, which is the hanging-wall, and grey, acidic lavas and sediments, which form the footwall. These rocks are cut by irregular basic intrusions that vary in composition from diorite to hornblendite, and by small acidic dykes . Tourmaline is locally common in the hanging-wall rock near the ore.The ore occurs in brecciated, silicified, and ·slightly carbonatized rock. Arsenopyrite is the main sulphide and the gold is associated with it. Pyrrhotite is locally abundant and minor pyrite, chalcopyrite, sphalerite, galena, and cubanite have been noted. Two orebodies are known, the Dick and the Toots. The Toots, which is much the smaller of the two, is about 1,000 feet west of the Dick."

Jan 1, 1954

By T. Sakai

Present authors have succeeded in single pass large draught rolling of AZ31 and ZK60A magnesium alloy sheets below 200 °C without heating rolls by raising rolling speed above 1000 m/min. Heavy reduction larger than 60% can be applied by single pass high speed rolling even at room temperature. The rolled sheets showed fine recrystallized microstructure by dynamic recrystallization. The improvement of workability at lower rolling temperature is due to temperature rise by plastic working. In high speed rolling, almost all of the work done by plastic deformation is converted into the heat that raises the temperature of the sheet during rolling because the heat did not flow out of the sheet by conduction and radiation within very short time.

Jan 1, 2006

By François Baillargeon

Two types of ore deposit provide the bulk of the world nickel production. They are the hypogene magmatic massive sulfide deposits and the supergene lateritic deposits. Platinum group elements (PGE) are also extracted from magmatic sulfide deposits. Recent sky-rocketing price of palladium has prompted the mineral industry to seek alternative resources. In such a manner has emerged the Lac-des-Iles type of target, a very low sulfide-bearing bulk tonnage type of deposit. Furthermore, unconventional (e.g. non-magmatic) types of deposit are now sought more intensively (Wilde et al., 2003). Considering both this trend of the PGE Industry, and that only a few magmatic deposits account significantly for the world nickel production, someone may wonder if a diversification of the hypogene nickel resources base would not be needed in the near future. Laterites are residual deposits developed on ultramafic rock under wet tropical climate. Are all ultramafic protoliths equal to generate high-grade lateritic deposit? Are some preweathering processes important to generate favourable ultramafic protoliths? The mineralogical heterogeneity of some ?dry? lateritic nickel deposits renders their ore beneficiation difficult. Is the type of nickel-bearing mineral found in the protolith a significant factor influencing the laterite heterogeneity? To contribute to answer all these questions, we have undertaken a research project on the nickel occurrences of the southern Quebec serpentinite belts. Why choosing this specific region for such a project? First because, due to continuous mining of asbestos ore since 1870, the serpentinite belts of this region are among the best exposed and studied in the world. Secondly, this region host a complete spectrum of nickel deposits that have been described before in the scientific literature. Furthermore, this region is slightly to moderately metamorphosed which make it perfectly suited to study the departure from magmatic nickeliferous paragenesis through various metamorphic conditions. As a matter of fact two orogenic events affected this region, the Taconian, in Ordovician time, and the Acadian during the Devonian. The magnitude and the timing of these dynamo-metamorphic events vary considerably through the region (Gauthier et al., 1994). These variations are now well constrained due to precise age dating.

May 1, 2003

By E. G. Baltuch

Natural Ventilation in mining and metallurgical processing applications is key to proper operation function. There are number of ventilator designs available to a project team or design engineers, the selection of which will affect both the type of building structure required, project costs and design performance which is difficult to rectify or re-engineer once implemented. Research and applied results, such as that performed by Air-Therm Inc., demonstrates that computational fluid dynamic simulation allows for 5 dimensional observation, analysis and optimization at significantly lowered cost than previously possible. These results have been fully implemented on a number of mining and metallurgical applications and the company continues to study, optimize and innovate as new tools become available to provide the best possible engineered solutions for particular applications.

Aug 1, 2013

By D. L. Griffith

THE realization by metallurgists of the important effect that traces of impurity may have upon the properties of a metal, and their steady demand for purer and still purer metals, have made the special cools for 'trace' analysis of increasing value. In the United States at least, spectrographic analysis is becoming the standard method for determining the impurities in zinc die-casting alloys. The Hudson Bay Mining and Smelting Company, as a producer of virtually pure zinc, uses the spectrograph to control the purity of its products, and-as the electrolytic method is employed here-to control both the impurities in the electrolyte and those 'trace' elements, which, while they do not contaminate the zinc, have a great effect on the plating efficiency. The general plan of the laboratory is shown in Figure l; the housing for air purification, which is on the roof, is indicated by broken lines. One of the chief factors affecting the layout was the easy way in which a spectrographic assay can be spoiled by contamination. To minimize the quantity of dust tracked in, the laboratory was made separate from the general research laboratories, and an office was placed between the two. This arrangement has its drawback because of the traffic through the office, but it has effectively cut down dust. For similar reasons, the available space was subdivided into a number of small rooms, and the air currents in the laboratory were so arranged that dust would be carried where it would do least harm. Air is drawn in at the roof over a 50-kilowatt bank of Calrod heaters, through Annis air filters, by a No. 4 Sirocco fan. Most of it is forced into the spectrograph room, but some goes to the office and darkroom. The air flow is from the spectrograph room, through the plate-measuring room, into the chemical laboratory, where it is exhausted by a No. 1% Sirocco fan on the fume hood. Air can also re-circulate from the plate-measuring room back to the heater. The arrangement is such that the air in the laboratory is maintained at higher pressure than the outside air; consequently, no dirt enters through cracks about the windows and doors. A thermo-regulator holds the temperature constant within one or two degrees; only on the hottest days in summer does the temperature rise enough to affect the focus of the instrument.

Jan 1, 1940

By JOHN H. HUDSON

Ceramic clays of the Prairie Provinces range in age from Lower Cretaceous to Pleistocene and Recent. Two significant ceramic clay horizons are the Paleocene Willo wbunch Member of the Ravenscrag Formation in Southern Saskatchewan and the Upper Cretaceous Whitemud Formation, which is found in Saskatchewan and Alberta. The Willowbunch Member is worked at one locale in Saskatchewan; the Whitemud Formation is worked at several locales in Saskatchewan and Alberta. Bentonite operations are found at Morden in Manitoba, Rosalind and Onoway in Alberta, and Wilcox in Saskatchewan.

Jan 1, 1984

By Dirige. A. P. E.

A study was conducted for an operating mine to determine the appropriateness of its tailings material to be used for the preparation of a low modulus, high density backfill. The research was initiated due to issues arising from increased observations of compressive failure of backfill placed in stopes and inconsistent backfill behaviour (i.e. increased backfill brittleness and modulus). Backfill materials investigated were classified tailings and de-slimed tailings. Characterization of the physical properties of the classified and de-slimed tailings materials was conducted to assess the effect that these material properties would have on the strength and deformation behaviour of high density backfill products made using them. Such behaviour was investigated to determine whether differences in tailings physical properties would influence the strength and modulus character of the backfill materials. Uniaxial (UCS) and consolidated-undrained triaxial compression strength tests were conducted to determine strength performance and deformation behaviour of backfill. This paper presents the results of the backfill material characterization study and how different particle size distributions affected the strength performance and deformation behaviour of the different backfill mixes. It also demonstrates how stress-strain curves generated from material strength tests were used to evaluate variation in high density backfill mix response when such materials were subjected to unconfined and confined (triaxial) compression loading.

Aug 1, 2013

By S. Ando

The fatigue crack growth behavior of magnesium single crystal has been investigated, CT (compact tension) type specimens with different notch orientations were prepared. In the case of notch plane and direction are (1-210) and [10-10], fatigue crack propagates parallel to notch, From TEM observation, it is found that pyramial slips occures at the crack tip. When notch is normal to basal plane, a fatigue crack propagates [0001] and parallel to basal plane depending on stress intensity factor range, In the case of notch parallel to basal plane, a fatigue crack propagates through straight route with some {10-12} twin, Fatigue crack growth rate, da/dN of A- and B- specimen is lower than F-specimen with crack parallel to basal plane.

Jan 1, 2004

By J. -C. Sztuke, M. Cao

ABSTRACT Wash water and polyethylene oxide (PEO) were used in the flotation of quartz and coal. Wash water decreased entrainment of –15 µm quartz. The optimum superficial wash water rate was 0.05 cm/s. PEO also lowered entrainment. The combination of wash water and PEO led to a slight further reduction in entrainment. For 1:1 mixtures of –15 µm quartz and –300 µm oxidized coal, the combined use of wash water (0.05 cm/s) and PEO increased the separation efficiency from approximately 30% to > 70%, whereas wash water alone at 0.05 cm/s did not lead to a discernible increase.

Jan 1, 2014

By Ron Bradburn, Derek Perkins

"The Brenda mine is located in south central British Columbia, 22 km north west of Peachland, in the heart of the Okanagan Valley. Situated at an elevation of 1500 metres, the mine area straddles the divide between the headwaters of Trepanier Creek and Peachland Creek. These flow into Okanagan Lake, the chief valley water resource located 1100 metres below. The creeks are of great significance to the water management of the area as they constitute the water supply for the Municipality of Peachland, a thriving retirement community with a population of 5000. A location map is shown in Figure 1.The history of the Brenda Mine operation has been well documented previously. After twenty years of operation, the open pit mine shut down in June 1990 due to the depletion of its ore reserves. During the course of its life, it produced 109 million tonnes of waste rock which is thought to contain approximately 0.10% copper as chalcopyrite and 0.015% molybdenum as molybdenite stored in four rock piles around the pit. Similarly, approximately 200 million tonnes of tailings were produced grading 0.015% copper and 0.005% molybdenum. During operation, tailings were hydrocycloned to produce a coarse sand for dam building with the fine slime stored behind the dam. It is estimated that 40% of the tailings were used for the dam construction. The layout of the mine site is shown in Figure 2.The mine was operated under a zero discharge permit. This was achieved by diverting practically all surface water flowing towards the mine area around the site. Water affected by mine operations, was discharged to the tailings impoundment, and recycled to the mill for reuse. The recycle rate was 90% and seepage from the tailings embankment and saddle dam was pumped back to the tailings pond. Because acid drainage was not a problem with the low grade Brenda rock, runoff from the rockpiles was initially released to the local environment. However, due to the alkaline nature of the waste rock, dissolution of low concentrations of molybdenum in the site runoff waters became evident by the late 1970's. The molybdenum content of Peachland Lake, the water reservoir for the municipality of Peachland, approached the Canadian Drinking Water Standard of 0.25 ppm. By 1979, a series of diversion and collection ditches was completed to direct all runoff water from the rockpiles to the tailings impoundment area. This had a significant detrimental effect on the site water balance causing it to go into a considerable surplus condition. During normal operation, this oversupply was contained by the rate of tailings dam building. An economic shutdown of the mine during 1984 forced a limited discharge from the site to protect the integrity of the tailings dam."

Jan 1, 1995

By W. J. Jenner

"Introduction The Saskatchewan Power Corporation is a provincial crown corporation which operates under a mandate to supply all customers within Saskatchewan with electricity and natural gas. The Saskatchewan Power Corporation operates two coal mines within the province of Saskatchewan. The Souris Valley Mine is located a few miles south of the city of Estevan and produces approximately 300 000 Mg of lignite per year. The lignite is shipped about four kilometres by truck and burned at the 882 MW Boundary Dam Power Station, also owned by the Saskatchewan Power Corporation. The Poplar River Mine is located just south-west of the town of Coronach, Saskatchewan which is some 190 kilo metres west of Estevan. This mine produces approximately 1 675 000 Mg of lignite per year. The lignite is shipped seven miles by rail to the Saskatchewan Power Corporation's Poplar River Power Station. The Poplar River Mine is the sole sup plier of fuel to the Poplar River Power Station, which generates some 300 MW of electrical power. A second 300 MW unit is due to be commissioned at the Poplar River Power Station in mid-1983 and the Poplar River Mine will have doubled its capacity to approximately 3 350 000 Mg per year by that time: Souris Valley Mine Geology The Souris Valley Mine extracts lignite from the Estevan seam of the Ravenscrag Formation. This formation is of Tertiary age and was deposited during the Paleocene Epoch. The Ravenscrag Formation outcrops throughout southern Saskatachewan and all coal mined in the province occurs in this formation. Ravenscrag sediments are deltaic in origin and are composed of a series of fine sands, silts, clay and lignite deposits."

Jan 1, 1985