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By C. H. Tiernon

"This paper was' prepared to emphasize the part that coal washing tables can play in the development of many of the reserves of coking coals in Western Canada_ It covers a brief history of the development of the coal washing table through the present third-generation unit, which suspends from overhead steel beams and is driven by a counter-rotating gear mechanism. The design and operation of this unique table are covered in detail.An analysis of actual operating data is included, with explicit statistical breakdowns of the table products. The data used were actually produced by operating coal companies, and also produced by the United States Bureau of Mines while gathering data for a research investigation. Table feed capacity is discussed, as well as performance criteria and the parameters of relative table performance. Several typical table flowsheets are described, emphasizing the specific reasons for their use. The paper covers the past and present value of the table to the United States coal industry, and makes mention of the newest addition to the family of suspended, multiple-deck, counter-rotating, gear-driven, coal washing tables, the CONCENCO ""88"" Deister table."

Jan 1, 1973

By Dale Verran, Jared Orynik, Chad Sorba, David Bronkhorst

Denison Mines Corp. (“Denison”) has a 90% interest in the Wheeler River Uranium Project (“Wheeler River”) located along the eastern edge of the Athabasca Basin in northern Saskatchewan between the Key Lake mill and the McArthur River uranium mine. The project is host to the high-grade Phoenix and Gryphon uranium deposits, discovered by Denison in 2008 and 2014 respectively, which include combined Indicated Mineral Resources of 132.1 million pounds U3O8 (1,809,000 tonnes at an average grade of 3.3% U3O8). The Pre-Feasibility Study (“PFS”), completed in accordance with NI 43-101 in September 2018, is highlighted by the selection of the In-Situ Recovery (“ISR”) mining method for the development of the Phoenix deposit, with an estimated average operating cost of $4.33 (US$3.33) per pound U3O8. Phoenix is the highest-grade undeveloped uranium deposit known globally, including Indicated Mineral Resources of 166,000 tonnes at 19.1% U3O8 for 70.2 million pounds U3O8. The paper aims to provide a summary of Wheeler River and an overview of the proposed development of the Phoenix and Gryphon deposits according to the PFS completed for the Project. Further details regarding the PFS, including additional scientific and technical information are described in greater detail in the NI 43-101 Technical Report titled "Pre-Feasibility Study for the Wheeler River Uranium Project, Saskatchewan, Canada" dated October 30, 2018 with an effective date of September 24, 2018. A copy of this report is available on Denison's website and under its profile on SEDAR at www.sedar.com and on EDGAR at www.sec.gov/edgar.shtml.

Jan 1, 2020

By Nicholas Macrae Steven

Abstract - The Shaba-type Luamata Cu-Co(-Ni) deposit (11°50_S, 24°28_E) is located in a tectonic slice of Katangan Roan Supergroup (Mines Group) sedimentary rocks, surrounded by younger Kundelungu Supergroup lithologies in the external fold and thrust belt of the Lufilian Arc. Luamata is a classic central African copper clearing in dense woodland, visible as a tonal botanical anomaly on Landsat imagery. Supergene Cu-Co mineralization (especially malachite and subordinate chalcocite, digenite, covellite, and copper and cobalt oxides) and, probably hypogene, bornite, and chalcopyrite are hosted by altered, but essentially unmetamorphosed, moderately dipping, dolostones and dolomitic shales. Alteration products include talcose dolomite, sericite rocks and intense silicification and brecciation. Friable yellow shale is best mineralized with cobalt (up to 0.43 wt%), whereas, highest copper grades occur in brecciated, silicified shale (up to 13.5 wt% CuO). Soil copper and cobalt contents are up to 2.2 and 0.6 wt%, respectively. A newly identified nickel zone (where soil contents exceed 0.1 wt% Ni) fringes the Cu-Co deposit. Polymictic, matrix-supported breccias with a calcareous matrix that underlie the Cu-Co deposit are interpreted to be fluidization breccias related to thrust tectonics and the emplacement of the Mines Group slice. Although small compared to the Kolwezi district Shaba deposits in the Democratic Republic of the Congo, Luamata exhibits all the classic features of an ore deposit type (with low calcite contents), whose high metal concentrations could potentially be very profitably exploited by low-cost opencast mining and hydrometallurgical recovery methods.

Jan 1, 2000

By Luis Magallanes-Hernández

"Industrias Peñoles, S.A. de C.V. (Peñoles) in Mexico, is a major silver producer. The Peñoles Mining Division has eight Mining Operations and in seven of them, flotation is used to concentrate the metal and mineral values. Common metals and minerals values are: metallic gold and silver, gold-silver alloys, silver sulphide minerals (acantite, pyrargirite, argentite, proustite); lead sulphide mineral, galena; zinc sulphide mineral, sphalerite; and copper sulphide minerals (chalcopyrite and bornite).In the last years, a special emphasis has been given to using modal analysis to identify ore mineralogical limitations, in order to direct efforts into key areas where opportunities exist to improve the metallurgical results.This work aims to share Peñoles mineralogical and metallurgical results, through presenting, discussing and drawing conclusions on these results; as well as pointing out areas where more work is needed to improve the Concentrator´ performance.PEÑOLES BACKGROUNDPeñoles´s mission is to add value to non-renewable natural resources on a sustainable manner. It was established in 1887, and it is a mining group with integrated operations in smelting and refining non-ferrous metals, and producing chemicals. Peñoles is the world’s top producer of refined silver, metallic bismuth, and sodium sulphate, the leading Latin American producer of refined gold, lead, and zinc.Peñoles Mining Division is integrated into eight mining business, located on five different states in Mexico. Metal productions for the Mining Division during 2003 were: 343 thousand gold ounces, 48.4 million silver ounces, 81.3 thousand tons of lead, 235.1 thousand tons of zinc, and 10.6 thousand tons of copper."

Jan 1, 2005

By A. Boehm

"For recycling LD slag into the steel making process, the phosphorous containing calcium silcate phases have to be removed from iron oxide phases. One possible technical solution could be magnetic separation in a wide range of susceptibilities from ferromagnetic to paramagnetic. To check the feasibility of magnetic separation the distribution of the magnetic susceptibility in size classes as well as the liberation of the phosphorous containing phase were evaluated by a new method combining two dimensional physical property analysis with QEMSCAN analysis. The particle size classes of energy controlled comminution products were subdivided into fractions of defined magnetic susceptibility using a hand magnet of well known field properties (pick up method). On the one hand the susceptibility classes were wet assayed on the other hand analyzed by QEMSCAN followed by data evaluation using iDiscover 5.3.1(FEI), which was adapted to the data structure of two physical properties (size and magnetic mass susceptibility). The results allow the comparison of mass based (3D) cumulative distribution of grades from the wet assays with the area based (2D) distribution from QEMSCAN analysis, in order to control a systematic (size dependent) stereological error for this special type of material. As the physical separation property forms a crucial parameter the results from the liberation analysis by QEMSCAN can be interpreted more profound with respect to an expectable separation result. Once the various mineral compositions of the particles are assigned to the physical properties the Henry Reinhardt chart serves to predict the best possible separation result and thus the feasibility of a separation technique.INTRODUCTIONThe two Austrian steel plants operated by voestalpine AG produce about 650,000 t (voestalpine 2014) of LD slag in the course of steel production from pig iron according to the basic oxygen process blowing oxygen in the converter by an oxygen lance. The process is also known as the Linz Donawitz (LD) steelmaking process. By the addition of lime (CaO), carbon, phosphorus, silica, manganese and sulfur, which are present in the molten pig iron, shall be oxidized and bound in the slag either as oxide or silicate phases, or leave the slag in the gaseous phase (CO). The average chemical composition of the investigated LD slag is given in table 1."

Jan 1, 2016

By Paul Clark

Generation - Profile l 9,726 megawatts (MW) of capacity l 46,877 gigawatt hours (GWh) produced at an average plant availability of 88.4% l 47 facilities in four geographies: Canada; the U.S.; Mexico; and Australia l Fuel mix of coal (62%), gas (26%), hydro and renewables (12%) l 23.2 million tonnes of coal mined l 47.0 million gigajoules (GJ) of gas consumed

May 1, 2004

By G. K. Lee, E. R. Mitchell

Designers of combustion processes may select aerodynamic conditions which produce only superfine fly ash. Although it is not usually anticipated that this will create a problem, such as has been found to agglomerate in high-velocity gas streams, to plug mechanical dust separators in a short time, and to contribute to atmospheric pollution. The problem is a fundamental one, and may be approached in several ways. The authors, in the course of their combustion research program, had occasion to examine the agglomeration of ash, ranging from sub-micron to 17 microns in size, produced in a (coal and oil) dual-fuel-fired steam generator. Several theories, supported by extensive laboratory studies, have provided some understanding of a probable mechanism of agglomeration. As a result, certain precautions are suggested in the design and selection of combustion processes and equipment.

Jan 1, 1962

By P. Quinn

"The Venturi-aerated flotation column (VAC) is based on a reactor and separator design for a new generation of flotation machines. The reactor is a Venturi tube, where the air/slurry contact takes place with intensive aeration for efficient particle collection. The separator is a column of 1-3 m length that provides quiescent hydrodynamic conditions for effective separation of bubble-particle aggregates from the remaining slurry.Aeration in the Venturi tube occurs via two mechanisms: air dispersion and nucleation (cavitation). By forcing air through a restricted passage with a fast flowing slurry stream, air is dispersed into fine bubbles. Bubble formation due to cavitation occurs on the surface of particles in the low-pressure section of the Venturi, from dissolved air contained in the liquid.Size-by-size recovery and flotation rate constants were determined for a small-scale laboratory Venturi-aerated flotation column. The results were compared to those obtained in a laboratory 2.2 L Denver cell. It is shown that the Venturi-aerated flotation column has slightly slower flotation kinetics to the Denver cell, but with much higher flotation selectivity. A portable Venturi-aerated flotation column can effectively be used to investigate process or equipment problems in operating plants.INTRODUCTIONFlotation processes can generally be divided into two sub-processes: 1) selective collection of hydrophobic particles by air bubbles and 2) separation of bubble-particle aggregates from hydrophilic particles that remain in the pulp. The methods of aeration, or bubble generation, control the mechanism of particle collection by either collision with, and subsequent attachment to bubbles, or by in situ bubble formation on the surfaces of hydrophobic particles. A flotation device should provide optimal aeration conditions for efficient particle collection and a suitable hydrodynamic environment for effective removal of bubble-particle aggregates from the remaining pulp."

Jan 1, 2002

By Ning Shi

This paper suggests an alternative design approach for an innovative shovel dipper, for use in ground conditions where cutting of virgin ground rather than scooping of blasted material is required. Not only does the new design have an optimized dimension ratio (width:height:depth) and attachment arrangement (angle, position), but also a non-linear pro¯le in 2D and 3D. The approach is based on the simulation of a shovel's duty cycle to verify a pilot dipper model. In order to achieve a realistic simulation that could be used to evaluate a dipper design, the model is e®ectively a descriptor of actual shovel activity under soft ground conditions. The shovel geometry, motion and operation, with an emphasis on digging and dumping kinematics and dynamics are the principal elements of the simulation. The simulation considers a fresh face location, repeating tucking, digging and dumping swing motions within the geometric range of the machine, ending when no more face material remaining within reach without re- positioning. The simulation yields digging force, friction force, trajectory, ¯ll time, ¯ll factor, etc, which may be integrated into two basic considerations: power draw (output) and volume delivered (production), as indicators of dipper performance. The simulation has been used as a tool to modify an existing dipper design, prior to looping further simulation cycles. Ultimately, an optimized or totally-new-concept shape is realized. A prototype dipper as a fractional scale model will be built to verity the performance under actual mining conditions.

May 1, 2004

By R. F. Favreau, L. C. Lang

"In modern blasting technology blasts are designed and analysed on an energy-mass-time relationship. The energy of the explosive is derived by computer analysis and the work potential of the available energy is expressed in numerical values. The mass involved in the blast is determined by the geometry of the blast and by the rock density. Time is also a relevant parameter, because time is required to complete the three basic stages of the breakage process.For successful application of the blasting parameters the basic mechanism of the breakage process must be understood.The physical-mechanical properties of the rock, local structural geology and the thermodynamic properties of the explosives can be brought together to create a computer model of a blast with which it is possible to predict separately the results of each parameter and to express the predicted degree of change in any parameter by actual numbers.A long-range project has started to create a ""bank"" of rock properties for as many Canadian and foreign mines as possible. A computer model has been successfully applied to predicting the effect of varying the ratio of spacing to burden at constant rock volume and significantly improved results are achieved, as the S/B ratio is increased up to about 2 to 2.5.High-speed photography has been applied to determine the time that has elapsed between zero time and the beginning of movement of the mass. The results assist in determining minimum and optimum delay time required for multiple-row blasting.The approach as described in the paper is now well proven and is clearly superior to previous methods based on powder factors and human assessment."

Jan 1, 1972

By F. Doxey

Introduction Numerous papers have been written dealing with the construction and functions of, and the environmental conditions created by, Diesel locomotives. Therefore, it is not my intention to attempt to deal with these phases of Diesel transportation other than to make reference to them in ?relation to and in connection with actual operation. The rapid expansion of industry during recent years and the necessity of products being made available at competitive prices in home and world markets has made the demand for cheaper coal a very serious factor for the coal industry. This condition has meant each coal producing country looking into ways and means whereby greater productivity and reduction in cost could he achieved. Surveys made show that, in addition to face mechanization, savings, in some cases substantial, can be made in transportation. Ventilation The most efficient mines are in-variably the well ventilated ones, for it is true that, where there is good ventilation, there are usually good roads. These combined factors are very essential where Diesel locomotives are used. Good roadways and track allow speed, and good ventilation dilutes rapidly any disagreeable exhaust gases. Locomotive Development In the older types of auxiliary rope haulage, coal hauled per haul-age hand is usually very low.

Jan 1, 1951

By Peter Wells, Adrian Sabau, Turgut Yalcin

"The nickel ores of Sudbury contain substantial amounts of the gangue mineral pyrrhotite (Fe7S&) which causes certain diflculties in the milling of these ores. This paper proposes a process called “magnetoflotation” as an effective means of dealing with pyrrhotite. The method reduces the pyrrhotite content of concentrates by applying a magneticjield on the path product as it leaves the flotation cell.Successful performance of magnetoflotation requires the optimization of several variables. In this study, three of the variables (air flowrate, collector concentration, pother concentration) were investigated by Box- Wilson experimental design, and others (magnet speed, grind size, pulp density, flotation time) were examined individually. The process was tested on a Falconbridge nickel ore, assaying 1.92% Ni, and under the best operating conditions, a concentrate was obtained with 13.56% Ni grade and 74.32% recovery in a single step. Further improvements to grade and recovery were possible by cleaning and scavenging. The same ore was also tested with conventional methods for comparison, and results indicated that magnetoflotation performed better.INTRODUCTION“Magnetoflotation” refers to the process of carrying out magnetic separation and flotation simultaneously within the same device, and is intended to prevent magnetic minerals from reporting to the froth products while non-magnetic minerals are being floated. Typical cases where this method might be beneficial include the processing of magnetite and nickel ores. Its use on magnetite ores has been reported elsewhere [Yalcin, 1992; Yalcin, 19931. This paper describes its application to nickel ores, more specifically to the nickel ore of Falconbridge Limited in Sudbury."

Jan 1, 1999

By G. I. Mathieu, R. W. Bruce

Flotation schemes for the separation of molybdenite from other minerals are based on utilizing the Inherent hydrophobicity of molygdenite (Fuerstenau1). This natural floatability was attributed to the crystalline structure of molybdenite by Gaudin et al.2 who suggested that any surface formed by the rupture of van der Wall's bonds should be hydrophobic and, therefore, naturally floatable. Other authors argued that "natural floatability" is dependent of adsorption of hydrocarbon ions and/or molecu1es on the surface of the minerals. This theory, albeit-c questioned 1,2 has long been recognized in actual practice of molybdenite flotation as the latter in carried out with hydrocarbons, such as fuel oil, kerosene and stove oil. Although conferring ready floatability to molybdenite, these presents generally have little effect on other sulphides and silicates. However, talc is a noteworthy exception because of its innate floatability4. Not withstanding the reason for this behavior which has also been attributed to crystal structure2 its end results as in the case of molybdenite is an immediate flotation response to frothing oils arid kerosene, as was observed by Baranovski5, Sutherland and Wark6.

Jan 1, 1974

By J. P. Harrison, M. Grenon

"This paper summarizes the results of numerical studies on drift stability in moderately jointed rock masses. It investigates the relative pertinence of geomechanical factors such as joint orientation, spacing and stress regime. This is undertaken using a distinct element model and a series of parametric studies. IntroductionIn evaluating the stability of drifts in jointed rock, it is often necessary to compromise by employing models that capture the complexity of the rock mass, but which are still simple enough to allow for their routine implementation. The distinct element method can arguably provide an eloquent method to accomplish this. This paper explores the applicability of the method by means of a parametric study aiming to identify the dominant factors that influence the stability of drifts in moderately jointed rock. To this end a commercially available 2D distinct element numerical model was used. A series of techniques are presented in an effort to quantify the results of any instability predicted by the model.This paper also demonstrates a case study where a 3D joint network model was integrated into the distinct analysis software package. The advantages, as well as the current limitations of this approach, are discussed."

Jan 1, 2001

By Peter Claus

In the last years, supported gold catalysts with particle sizes smaller than 10 nm have attracted a lot of attention. While gold bulk metal is rather inert in chemical reactions and, thus, is of low interest for catalysis, highly dispersed gold particles supported on oxides as TiO2 or ZrO2 show surprisingly high activities in some reactions important for the chemical industry. The oxidation of carbon monoxide at low temperatures is mainly used as model reaction to study the unusual properties of gold catalysts [1]. On the other hand, to evaluate the catalytic potential of gold, other chemical reactions which allow to control also the selectivity have to be considered. The selective hydrogenation of ???-unsaturated aldehydes to allylic alcohols is of both commercial relevance (e.g. in fine chemical and pharmaceutical intermediate production) and specific scientific interest [2]. Note that thermodynamics favors hydrogenation of the C=C over the C=O group (stronger negative free reaction enthalpy of 35 kJ/mol), and for kinetic reasons the C=C bond is more reactive than the C=O group. Thus, in the presence of most of the conventional hydrogenation catalysts, based on Pt, Rh or Pd, -unsaturated aldehydes such as acrolein and crotonaldehyde are hydrogenated predominantly to the saturated aldehydes and only to a minor extent to unsaturated alcohols. Therefore, it is desirable to find catalysts which are able to control the intramolecular selectivity by hydrogenation preferentially the C=O group while keeping the olefinic double bond intact (Fig. 1).

Oct 1, 2003

By Harry V. Warren

THE Dolly Varden Mine is situated in the Kitsault River valley, eighteen miles from the head of Alice arm, in the Nass River mining division of British Columbia. During the years 1919-21 it was operated by the Taylor Engineering Company, Limited, and produced 1,300,000 oz. silver from about 36,000 tons of ore. The ore was transported by narrow-gauge railway to Alice arm, and shipped to the smelter at Anyox for treatment. During recent years, a small quantity of high-grade ore has been extracted by leasers and shipped to the smelter at Tacoma, Wash. Unfortunately, the bonanza ores which occurred near the surface did nor persist to depth, and two hundred feet below the exposures only rare and unimportant patches of ridi ore have been found. Two opinions exist as to the origin of this rich silver ore. One, advanced by V. Delmage (1, 2), is that the ores are hypogene, and the other, by G. Hanson(3, 4, S), is that the ores are the result of supergene enrichment. It is true that Dolmage first advanced his view that the ores are primary because they appeared to be analagous to Premier ore, which he had studied in detail and which he considered to be primary. The present authors have had access to excellent suites of material from both mines and consider the comparison well taken, the only essential mineralogical difference being the presence at the Premier mine, in addition to the silver minerals, of gold and electrum. Although the arguments put forward by Delmage have, in the opinion of the authors, never been refuted, nevertheless R. P. D. Graham(6), in a reference to the mine published in 1924, describes the ore as of supergene origin, and since then nobody appears to have challenged this statement. Indeed, in 1935, Hanson re-affirmed his earlier conclusion(5).

Jan 1, 1942

"In a continuing investigation into the development of uranium alloys for armament applications, some complex base alloy corn positions were modified by varying the amount of alloying elements and by removing one or two of the alloying elements in turn from the base alloys. These uranium-base alloys were specially formulated in a search for heat-treatable, high-strength, ductile, high-density alloys. All alloys studied were ternary, quaternary or more complex alloys of uranium with molybdenum, zirconium, niobium and vanadium. Each cast alloy was studied under three different heat-treatments, and its mechanical and corrosion properties were determined. It was found that although most of the alloys studied had the hardness and strength required, they were extremely brittle and notch-sensitive under tensile stresses."

Jan 1, 1968

By J. Hansen

"ABSTRACTThe paper addresses the application of automated monitoring, control, and navigation to improve dragline performance. SummaryImproving dragline performance in the Canadian coal mines is critical to the continued success of the industry. Draglines represent a large capital investment and coal prices are low by historic standards. This paper argues that the introduction of monitoring, control, and navigation on draglines offers an opportunity to significantly reduce a dragline’s operating cost per cubic metre moved. To place the importance of this in perspective, a North Dakota mine calculates that every 1% increase in dragline productivity means a savings to the mine of US$340,000 per year. MonitorsAutomated dragline monitoring is a well established technology with commercial products available since the early 1980s. The three main reasons for placing monitors on draglines are (Walker, 1993):1. productivity increases: reduce variations between different operators’ performance across different shifts;2. quality increases: increase the percentage of ore and waste loads that go to the correct destination; and3. special projects (engineering projects): justify installing static field exciters and regulator upgrades; implement power management; aid operator training; study high performance buckets, rigging changes, and various excavation sequences.Mines as diverse as Kennecott’s Cordero- Rojo Complex in the United States and Natal Coal Corp.’s Optimum Mine in South Africa report dragline productivity increases of 10% to 20% in the region attributed to the implementation of dragline monitoring."

Jan 1, 2000

By D. S. Speakman

The copper-zinc orebody at Sherritt Gordon's Ruttan Mine occurs in a structurally complex area of the Rusty Lake greenstone belt in northern Manitoba. Problems in interpreting drill results indicated a large deviation, and the structural complexity an erratic deviation, of drill holes. This was confirmed when a surface hole was intersected 420 feet to the left of line on the 800 level. This problem acted as a catalyst in promoting a search for a suitable down-hole survey method. The instruments investigated included magnetic multishot and gyroscopic units as well as the ABEM Reflex-Fotobor. Only the Fotobor came close to meeting the company's needs of simplicity, reliability, accuracy and ownership. In this paper, the methods of operating this instrument, as well as the data extraction and reduction techniques, are described. Data on the accuracy and repeatability of the instrument are presented, and a tabular presentation of the results of surveying on 86 holes totalling 64,000 feet of drilling is made. Preliminary statements of the results of ongoing research on causes of hole deviation are presented and recommendations for minimizing deviation are given. The use of the survey device is recommended in areas of structural complexity, for very steep or backsight holes and where expected ore intersections are missing.

Jan 1, 1978

By H. Warren Newcomen

The southwest wall of the Lornex Pit at the Highland Valley Copper mine has been experiencing slope displacements since 1978. Measures to manage the displacements on previous pushbacks have included stepping out, scheduling pushbacks to unload the crest of unstable areas, slope dewatering and mining with intensive slope monitoring. The final pushback on this wall is currently being mined and substantial modifications to the slope geometry could prove to be uneconomic. As a result, a campaign of surface water collection and diversion, horizontal drainhole drilling and deep well drilling is currently underway to maintain an acceptable degree of stability to the end of mine life. The various factors contributing to instability, including engineering geologic controls, rock mass strength, and surface and groundwater hydrology are presented. Movement trends, displacement magnitudes and stability analyses results are also discussed.

May 1, 2002