Search Documents

By Collin Bartlett, H. Storch

"Modern metallurgical processes operating with oxygen enriched air, such as the Outotec Flash Smelter and Flash Converter, generate very concentrated SO2 off-gas, which in combination with Outotec sulphuric acid plant technology allows the production of high pressure steam to be used for power generation. Outotec combines well proven technology of sulphur burning plants for this purpose with metallurgical plants.The application of Outotec’s proven LURECTM process enables processing of SO2 gas of up to 25 vol.-%. This process maximizes the energy recovery from the SO2 oxidation at a suitable high temperature level which can be turned into high pressure steam. The application of the Outotec HEROSTM heat recovery system enables the generation of low pressure steam from the absorption energy released at the intermediate absorption step. Additionally, energy is also recovered in the acid coolers for boiler feedwater pre-heating.The concept of integration of high and low pressure steam in combination with the pressurized operation of the boiler feedwater deaerator, thus heating up the boiler feed water to temperatures around 160…170°C, enables indirect transfer of low pressure steam (for deaerator operation) into more valuable high pressure steam, which improves the degree of heat recovery. This is the characteristic of Outotec’s HEROS+TM process.The increased generation of high pressure steam will in turn enable the generation of more electricity when compared to a standard traditional sulphuric acid process."

Jan 1, 2014

By Ernest Bohnet

Each mining operation is unique in some aspect ownership; ore body location, size, geometry, grade, mineralogy, hydrology, or geotechnical parameters; or constraints such as environmental regulations. However, all mining operations are alike in one aspect; the prime objective of any mining project is to maximize the return on the investment. This is the golden rule, or in the language of mining, the investor?s law of conservation. A mineral resource, by definition, does not become a minable reserve unless the mineral or minerals can be extracted economically (and legally). The three preceding sections have covered the various types of surface mining options. The choice of the most economic method is dictated primarily by the type of de-posit to be mined, the mining rate, and the physical characteristics of the deposit.

Jan 1, 2008

A number of gases, such as carbon dioxide, methane, water vapour, nitrous oxide, ozone and chlorofluorocarbons are transparent to incoming short-wave radiation, but are relatively opaque to outgoing longwave radiation. Variations in the concentration of these gases in the troposphere can alter the thermal balance of the earth's atmosphere. Outgoing terrestrial radiation which would otherwise escape to space, is trapped within the inner layer of the atmosphere, resulting in a greenhouse effect. It is estimated that at present greenhouse gases other than carbon dioxide, contribute about 50% to the greenhouse effect. However, in the future, the contribution made to the greenhouse effect by gases other than C02 will become increasingly more significant. Greenhouse gases arise from a wide range of sources and their escalating increease is largely related to an increase in the world's population, an increase in the standard of living of many areas and changes in lifestyle. The effect of increasing man-made greenhouse gases in the troposphere is unknown but it is proposed that it may increase temperature and may modify climate, agricultural response and land use. The sources of greenhouse gases are identified and found to comprise a wide range of activities. The contribution that coals use makes to the greenhouse effect is examined in detail. It is concluded that coals total contribution is small being about 10% of man made greenhouse gases. Envisaged expansion of coal's use will only cause a small increase in greenhouse gas emissions. Whilst developing technology for coal's use for power generation has the potential to reduce greenhouse gas emissions from new plants by approximately 25%.

Jan 1, 1989

By John F. Haberer

DURING the twentieth century Canadians have been steadily improving their standard of living. Originally, this improvement depended almost entirely upon the export of basic raw materials and a triangular system of trade with Great Britain and the United States. However, since the Second World War, Canadian living standards have improved still further because of the very rapid d0evelopment of secondary industries. As a result of this development, the present demand for scientists and engineers exceeds the supply, and interest in scientific research has never been greater. It is the purpose of this paper to discuss the professional and economic status of Canadian scientists and engineers over the past half century. GROWTH OF RESEARCH It is difficult to determine accurately the amount of scientific research conducted in Canada since 1900. However, ?prior to World War I, it was limited and was connected mainly with primary industries and health. Government departments did some; university science faculties, overloaded with teaching responsibilities, did a little; and industry, which consisted mainly of subsidiaries of American and British firms, depended chiefy upon foreign sources for new information.

Jan 1, 1956

By J. Laganiere

A considerable part of the sulphuric acid requirements of the Aluminum Company of Canada's Arvida smelter comes from the burning of 180-200 tons per day of zinc '"'sulphide concentrates in a 22-ft.-diam-eter fluidized bed roaster. The plant and its operation were fully de-scribed in a publication that appeared about ten year ago (1). A simplified flowsheet of the roasting and gas-cleaning sections of the plant is given in Figure 1. The wet zinc sulphide concentrates are un-loaded into a pug mixer, by means of a Pay loader, and mixed with water in a mixing tank to make a slurry of 80 per cent solids. The slurry is transferred to a .feed tank and then introduced into the roaster at a point four feet above the constriction plate, which is the height of the settled bed of zinc calcines. The roasting temperature is con-

Jan 1, 1963

By L. Morin, S. Mortazavi, K. Volchek, A. Demers, A. Di Feo

The objective of this paper was to investigate the possibility of reducing process (fresh) water and increasing recycled water (thickener tank overflow water). As part of the investigation, rougher flotation tests were done with the two water types and a mixture of the two (50%/50%). The effect of recycled water on the grade-recovery response and rougher recoveries was investigated. When thickener tank overflow was used (50% and 100%), the nickel+copper grade versus nickel recovery decreased. The decrease in the grade-recovery was due to higher pyrrhotite recovery. Also, there were no effects on nickel and copper recoveries, which was confirmed using multivariate statistical analysis at the 95% significance level. Keywords: Flotation, nickel, copper, water recycling, multivariate statistical analysis, MANOVA, reverse osmosis

Jan 1, 2020

By D R Quick

The Goodall gold mine is located 30 km east of Adelaide River, within the Pine Creek 1:250 000 map sheet, at 8 525 000 mN: 750 000 mE, on the AMG grid. The first gold was poured in April 1988 and the mine closed in September 1993, having produced 228 400 ounces of gold from 4.095 million tons of ore, at a head grade of 1.99 g/t. Oxide and primary ore was mined from one large open cut and low grade oxide ore from three smaller pits. The gold mineralisation was discovered in 1981 by means of a helicopter borne rock chip sampling survey, which delineated 13 discrete anomalies. Systematic grid sampling of rock chips outlined an area of 1300 m by 300 m within the 2.0 g/t contour. Over 7500 m of costeaning was used to delineate the A and B-Pod mineralised areas. Geochemical soil sampling played only a minor role in the discovery and geophysics none at all. By the end of 1984, 40 diamond drill holes had been completed and a resource of 3.63 million tonnes at 3.0 g/t calculated. In January 1985, Western Mining Corporation Ltd became a joint venture partner and funded exploration to cam a 60 per cent interest. Additional drilling led to a feasibility study in 1987, based on a Measured and Indicated resource of 4.25 million tonnes at a grade of 2.35 g/t. The host rocks are quartzo-feldspathic wacke and interbedded phyllitic siltstone, of the Proterozoic Burrell Creek formation. The main zone of gold mineralisation, A-Pod, occurs in a sub-vertical vein array, up to 50 m wide and 800 m in length, of quartz and sulphide veins (5-20 mm wide), It is parallel to and on the east limb of an upright, north plunging anticline. Five types of veining have been recognised, with the bulk of the gold mineralisation associated with quartz-pyrite-arsenopyrite and chlorite-quartz-pyrite veins. The gold occurs as particles, from 1-20 micron, as inclusions and along fractures in pyrite and arsenopyrite and to a limited extent in chlorite. The mineralisation is epigenetic and structurally controlled by fractures developed during an earlier folding event. The gold is assumed to have been derived from the underlying sediments of the Koolpin Formation by hydrothermal fluids emanating from the deep seated northern margin of the Cullen Batholith. Precipitation of gold may have been controlled by variations in temperature and pressure.

Jan 1, 1994

By Michel Dagbert

With the growing demand for energy, explora¬tion for uranium deposits has dramatically increased in the past few years. Since the early ages of uranium exploration, natural gamma ray logs has proved fast and convenient in locating and evaluating mineralized bodies. However, natural gamma ray logging is an indirect measure of the uranium content and in some circonstances, the radiometric signal can be 'altered in a very significant way. To check the presence of any distortion, statistical comparision of radiometric counts and chemical assay values for the same samples is generally performed. Of course in such studies, one inevitably mixes samples where the radiometric signal is really proportional to the uranium content and samples where this signal is influenced by many other sources or distorted before being recorded. Nevertheless, the average tendency leads to correction factors which are then applied to every radiometric reading in the deposit or portion of the deposit where the statistical comparison is made. To account for the "average" character of these correction factors, a parameter of uncertainty like a standard deviation of possible errors is associated to each corrected value. This parameter can be latter used in an ore reserve estimation when the weights assigned to samples should depend on the precision of their grade. The purpose of this paper is to present a new regression technique which can be used without any restrictive hypothesis like a normal or lognormal distribution. Different standard ways which can be used to statistically compare radiometric and chemical assay values for the same sample and to derive a correction factor for the latter will first be reviewed, after a general discussion of disequilibrium problems. The discussion and the examples will be restricted to the case of natural gamma ray logging in drill holes but the methods presented in this paper can also be applied to data from the radiometric probing of a working face or a truck load in an operating mine.

Jan 1, 1979

By George T. Motock

The author prepared the following report as the result of a trip to Germany in the summer of 1945 for the Technical Industrial Intelligence Commitee Subcommittee on Metals and Minerals. The purpose of this committee, which functions under the Joint Intelligence Committee of the Joint Chiefs of Staff of the United States Armed Forces and of which the Bureau of Mines

Jan 1, 1946

By Jirí Faltus

The paper deals with studying the impact of structural properties and anodizing of surface on the corrosion properties of extruded rods from commercial aluminium alloys: AA6082, AA6262, AA6012, AA2007 and new lead-free aluminium alloys AA6023, AA2015 and AA2111B. Samples were exposed to the corrosive atmosphere NSS, AASS in the chamber by EN ISO 9227. Surface of samples were either in the original state or anodizing by selected mode. The depth of corrosion attack and the form of corrosion attack are evaluated depending on the type of alloy, the metallurgical condition and surface treatment of the samples.

Jan 1, 2015

By W. J. Taylor

Every one having practical experience in making heating-gas knows how much room there is for improvement,, in order to avoid not only the production of poor gas, when good gas is most wanted, but also the waste due to burning gas on top of the fuel-bed, and the loss of both time and fuel in cleaning.* The producer which I have recently designed, and with which I am now experimenting with every prospect of success, at the oreroasting kilns at Chester furnace, is intended to remove these difficulties as far as possible, and at the same time to be continuous in operation. I have not had it at work long enough to get beyond the stage of experiment; hence, I will only at this time explain it in a general way, and illustrate it with a drawing, promising a more elaborate paper if it becomes the practical success I anticipate. The features of the producer are : 1st. The round dome-shaped revolving bottom; and 2d. Metallic water-cooled walls in place of the usual brick lining. As shown in the drawing, the bottom has a sleeve, which fits over the air-admission pipe, coming up through the center of the

Jan 1, 1887

By A. E. M. Warner

Inco Limited has long and extensive experience in converting nickel-copper primary smelting mattes over a broad range of nickel/copper weight ratios and combined nickel-copper-cobalt contents. At the Copper Cliff Smelter, the composition of the converter product matte has to meet the requirements of the matte separation process; at the Thompson Smelter, converter matte of a different composition is cast into anodes for nickel electrorefining; and in Soroako, Indonesia, a very low copper product matte is granulated for the Japanese market. Recently, Inco has conducted pilot plant testing of three possible nickel-copper matte continuous converting routes, namely flash converting, oxygen top blowing-nitrogen bottom stirring, and tuyere blowing. This test work has generated substantial new information on nickel-copper matte converting chemistry. This overview paper reviews the metallurgy of nickel-copper matte converting, in particular the behaviour of cobalt and the operating conditions required to meet the iron and sulfur specifications of the product matte. The relevant thermodynamic information is used to discuss the industrial data.

Jan 1, 2003

By J. E. Ostberg, G. Phragmen, A. Hultgren, S. Wohlfahrt

Detailed study was made of a number of rimming ingots, both low and high carbon, and especially upon effects of superimposed air pressure. Requirement to suppress core bubbles is between 10 and 15 atm; at 6.5 atm freezing was in semikilled manner and at 3 atm, steel was of rising type. Probable mechanism of freezing under various conditions is discussed. AN earlier paper' reported an investigation made by a committee for studying rimming steel ingots appointed by Jernkontorets in Stockholm. The present paper is the outcome of some further work done by the same committee. Since the characteristics of ordinary rimming steel are connected closely .with the amount of gas liberated during freezing and since this amount of gas is governed by the pressure, it was considered of interest to ascertain in what manner and to what extent definite pressures applied to the top of the liquid steel in the mold would affect the solidification process and the consequent structure of a rimming steel of ordinary composition. The experiments were made at the Domnarfvets Steel Works. The steel was made according to normal practice in a 4-ton Rennerfelt electric furnace. Ferromanganese was added in the furnace; no aluminum was added, with one exception. Analyses of the four heats are given in Table I. The top-poured ingots measured about 12 in. sq x 48 in. and weighed about 1300 lb. One or two ingots of each heat were allowed to solidify under pressure, using a special device for admitting compressed air to the upper closed part of the mold, as shown in Fig. 1. A heavy plate sealed with asbestos was bolted to the top of the mold. The plate had a tapered aperture for pouring. Immediately after pouring the hole was closed by a wedged plug, and compressed air was admitted through a hole in the plug. Because of some delay in applying the plug, full pressure was not reached immediately. The pressure was adjusted to the desired value as indicated by a manometer. In order that the interior of the ingot might have the benefit of the pressure, the freezing of the top crust was delayed by a refractory lining applied to the top part of the mold, Fig. 1. Ingots were also cast from each heat without applied pressure, and with and without refractory lining at the top. Axial sections of ingots were cut either of the whole ingot or of some part of it of special interest; sections were polished and usually etched.' To facilitate description of structures the following terms may be used for different types of ingots solidified under gas evolution: 1. Box-hat or boot-leg ingot: Abundant gas evolution during casting and during rimming; no rim holes. 2. Normal rimming ingot: Lively gas evolution during rimming; usually rim holes in lowest part of

Jan 1, 1952

By Ahmad Ghahreman, James McNeice

Separation of rare earth elements (REE) is often achieved by acid leaching of mineral concentrates followed by subsequent solvent extraction (SX), to purify individual rare earth metals (REM). Cerium, the most abundant REE, is usually the largest component of these ores. Demand for less prevalent REE, such as praseodymium and dysprosium; have led to a market saturation and price collapse of cerium. One method of improving the economics of REE separation is to remove cerium from solution prior to SX. This is accomplished via the oxidation of cerium (III) to cerium (IV), which precipitates as cerium hydroxides. This study probes the efficacy of four oxidants; hydrogen peroxide, sodium hypochlorite, potassium permanganate, and Caro’s Acid with the goal of improving cerium removal whilst minimizing REE and reagent losses. The effect of oxidant type and dosage, pH, cerium concentration, and temperature on the kinetics of the process will be discussed.

Mar 1, 2018

By Min Chen, Qinghua Liang, Weishan Yan, Yuan Feng, Shigang Wang

Various coal mine robots (CMRs) and unmanned aerial vehicles (UAVs) are implemented to explore unknown mines for improving the safety and efficiency of mining. It is challenging for CMRs and UAVs to achieve accurate positioning due to the absence of GPS, poor lighting conditions, and similar geometric features in complex mine scenes. LiDAR-based localization and mapping methods are admittedly more accurate than others, while long-time running in large-scale scenarios will also introduce non-negligible cumulative errors. This study presents a semantic-aided LiDAR simultaneous localization and mapping (SLAM) with loop closure, which leverages the uniqueness of mine intersection structure to establish stable semantic loop closure. Specifically, we propose a semantic intersection descriptor of translation and rotation invariance, which encodes 3D point clouds of the same intersection from different positions and viewpoints into a unified image. By using the semantic descriptor, we can construct a constant loop constraint when the same intersection is revisited from different directions to reduce cumulative drift. We provide experimental validation using large datasets collected in two large underground mines, namely, a simulated Edgar mine deployed in ROS Gazebo and a public underground mine dataset provided by ETH. Experimental results show that the proposed method has higher localization accuracy and outperforms the existing LiDAR-based SLAM strategies.

Aug 10, 2023

By J. P. Wilson

The Tessenderlo-Kerley Leach process has been shown to be effective in the removal of residual copper from molybdenite concentrates. Concentrates of varying mineralogy, including those containing relatively large amounts of chalcopyrite, have been successfully leached on laboratory and pilot plant scales. The lixiviant system is ammonia and ammonium bisulfite with air / oxygen addition. An abrasive is added which greatly enhances the kinetics, and it is subsequently screened out and reused. The dissolved copper is easily recovered using existing technology. Extraction profiles, reagent consumptions, and mineralogical data are presented.

Jan 1, 1999

By Wan-sub Kim, Joon-Tae Lee, Seongkyu See, Yong-Kyu Park

Softening heat treatment of CHQ alloy steel (Cr-Mo Steel) is a bottleneck process that requires 90% or more of the entire manufacturing process. In order to reduce the property deviation between edge and center and remove the low-temperature structure problems, CHQ products is heat treated by customers. This technology comes from the idea to solve the problem by applying the concept of “In-line isothermal transformation through initial quenching + heat source addition. Consider the stability of field operations, durability from high ambient temperature and fall of scale, Instantaneous heating and cooling control was required for the conversion of slow cooling and rapid cooling products. An electric heating system was applied to the underside of Stelmor air-cooling nozzle. Using the Scan Pyrometer, the feedback control was performed and fine temperature control was performed through the thermocouple by zone. Through the this technology, it is possible to develop and expand products that can be shortened or omitted by the heat treatment process of customers.

Oct 1, 2019

By Abolfazl Eslami, Masoud Zare, Ali Asadi, Ali Abrang

"Physical small scale models for study of deep foundations can be performed in simple chambers (1g), calibration chambers (CC), and centrifuge apparatus (ng) which involve some limitations and difficulties. In recent years, Frustum confining vessels (FCV) have been developed for physical modeling of deep foundations. This device is frustum of a cone shape that applies a steady pressure on its bottom and creates a linear stress distribution along its vertical central line. A new FCV which has been built in AUT is introduced. This device has a height of 1200 mm, top and bottom diameters of 300 and 1300 mm, respectively. Through the application of bottom pressure up to 300 kPa, the insitu overburden stress conditions equivalent up to 40 m soil deposits consistent to the embedment depth of commonly used piles. Observation indicated that there is approximately a linear trend of stress distribution, and this device can create realistic overburden stress in the desired control volume along the central line. Moreover, a couple of compressive and tensile load tests were performed on steel tubular open end model piles driven in sand with length of 750 mm and different diameters and L/D ratio between 8-15. Comparison of load capacity between tested and full scale piles demonstrate a suitable conformity for similar confinement conditions. Therefore, the FCV can be realized as an appropriate apparatus for investigation of piling geotechnical behavior and examination of construction effects.IntroductionDeep foundations are designed as foundation system for supporting heavy loads, high rise and important structures. Different theoretical, numerical and experimental approaches have been developed to study the geotechnical behavior of deep foundations. Experimental methods are employed to clarify directly pile-soil interaction and because of repeatability, analogy, rapid measurement and cost efficiency, physical modeling can be realized as an intermediate technique compared to element testing and full scale load tests."

Jan 1, 2015

By J Arola, B Kettunen, W M. Bond

Separation of fine and coarse particles as separate streams prior to flotation, and their differential treatments, could substantially increase recovery and reduce collector consumption. A series of simulations was carried out to quantify the benefits from plant scale implementation of such a treatment at the Ispat Inland flotation circuit (Minorca mine). The study involved detailed plant sampling and sample analysis to generate the data needed for simulation studies. Samples were taken from all the streams from flotation feed to final concentrate, as well as cell lips and cell pulp. Sampling was repeated for the second ore blend that was processed by the plant during different periods of a year. Sample analysis involved sieve analysis and size by size chemical analysis for total iron, magnetic iron and silica. Raw data were mass balanced, and flow rates within the circuit were calculated. Mass balanced data were used to calculate model parameters representing the existing conditions. Usim Pac was used for both mass balancing and simulation studies. Available pilot and bench scale data were utilised to define the modified flow sheet and expected performance. The simulated flow sheet included classification of flotation circuit feed by hydrocyclones. While the coarse fraction followed the existing flow sheet, the fine fraction was sent to a magnetic separator. Magnetic and rougher flotation concentrates were combined to form the final concentrate. Two simulations for each blend were carried out. The first one assumed that there would be no change in size by size kinetic behaviours of both gangue and magnetite due to this modification. This was named as the worst case scenario, in which particles had a longer residence time due to reduced flow rates within the flotation cells. The second scenario anticipated that there would be an increase in recoveries of gangue and magnetite going into froth launder due to more efficient use of collector in absence of fines. Results showed that pre-classification of flotation feed could improve the flotation recovery by 0.3 - 0.5 per cent, with the major benefit being significant reduction (40 - 60 per cent) in the amount of collector used.

Jan 1, 2005

By László Guczi1

Nanosize model gold particles with varying size were fabricated by deposition of a 10 nm thick gold film onto SiO2/Si(100) substrate by electron beam evaporation followed by modification using low energy Ar+ ion bombardment. The change in particle size were monitored by the Au 5d valence band states determined by ultraviolet photoelectron spectroscopy (UPS). The gold/iron oxide interface was studied by iron oxide deposition on gold. It was found that the energy profile of Au 5d valence band states are strongly redistributed with decreasing the gold particle size mostly affecting at the lowest and at the highest binding energies. The size effect in the UPS spectra can be interpreted by the energy redistribution rather, than by narrowing the 5d states. The iron oxide deposition increases the catalytic activity in CO oxidation whether it is on gold nanoparticles or on a continuous 80 nm thick gold film. The activity enhancement is significantly larger in case of gold nanoparticles. The interface interaction is operative in enlargement of the catalytic activity even if gold particles are not exposed to the surface, but they are located below the iron oxide layer.

Oct 1, 2003