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By A. Tylczak, C. Shook, A. Doogan-Smith, S. Loif, B. Hilscher, P. Nayak

"This paper discusses how to effectively conduct energy efficiency studies during the design of new mineral processing plants and plant expansions. Energy management studies for new plants are ideally conducted as part of the feasibility study, but can also be done at the detailed design stage prior to the purchasing of equipment. Energy management engineers work as part of the mineral processing plant design team.Such studies usually result in energy savings of approximately 3-8% of the predicted plant’s energy consumption and energy demand. Potential cost savings can be significant. A variety of mineral processing systems – crushing/grinding, pumping, materials handling, fans/blowers, compressed air, and others – are assessed within this study.Energy Management Information System (EMIS) studies can also be performed for the new plant or plant expansion, as an independent study. EMIS can be incorporated into the electrical and controls design of the plant.Most Canadian Utility companies fund new plant design studies and provide financial incentives based on the predicted energy savings and incremental cost of the more energy-efficient design. A new plant energy efficiency study improves the potential for energy reduction because only the incremental equipment cost is included in the project return-on-investment calculation. After the design and construction phases, energy efficiency projects must justify the entire cost of the upgrade, which is significantly higher than the incremental cost alone.This paper outlines the major steps of a new plant/plant expansion energy efficiency study, the available utility company incentives, and the areas yielding the largest potential energy savings.IntroductionThis paper discusses energy efficiency studies and energy management systems with regards to mining operations. Energy management refers to the systems of monitoring, analyzing, and optimizing energy usage within a facility. It includes energy efficiency optimization of the initial plant design as well as the implementation of an Energy Management System (EnMS) and Energy Management Information System (EMIS) for optimizing energy usage over the lifetime of the facility. An EnMS is the organizational framework and procedures for managing energy use; an EMIS is the system of monitoring, reporting, and tracking process energy use against targets."

Jan 1, 2016

By Fathi Habashi, Ahmet Deniz Bas

"The mechanism of leaching of semiconducting minerals such as PbS, ZnS, UO2, etc., has been the subject of intensive speculation by hydrometallurgy researchers in the early 1950s who assumed the formation of intermediate surface complexes that could be neither separated nor identified by physicochemical techniques. The electrochemical theory of leaching introduced in the late 1960s resolved this problem by comparing the leaching process to a corrosion phenomenon similar to the corrosion of metals. Few years later, experimental evidence showed that anodic and cathodic zones are formed on the dissolving mineral although no electric current is imposed on the mineral during dissolution. A discussion of these findings is outlined.INTRODUCTIONIn the early 1950s researchers realized that kinetic studies for leaching ores are as important as thermodynamic calculations. It was also during this period that the concept of species adsorption on mineral surfaces has dominated the interpretation of the mechanisms of most reactions. This may have been due to the fact that many researchers of this period came from the mineral dressing sector and were influenced by flotation theories. However, when the knowledge of lattice defects and the semiconductivity of minerals became known and their importance in extractive metallurgy was realized, there was a need to explain the leaching reactions in light of these modern theories (Habashi, 1969, 1970). Semiconducting minerals of importance in metallurgy are two categories: the sulfides such as those of copper, lead, zinc, and the oxides such as those of uranium."

Jan 1, 2016

By Amyn S. Dahya, David J. King

"The object of the paper is to discuss the developments in Carbon-In-Pulp (C.I.P.) technology for gold recovery. The CIP process is comprised of four major operations:(a) adsorption of precious metals onto activated carbon;(b) elution (stripping) of precious metals from the loaded carbon;(c) electrowinning of the precious metals from the concentrated eluate;(d) regeneration of the eluted carbon before recycle to the adsorption process.A detailed review of the technological developments in each of the above operations is presented together with a brief theoretical background of the underlying processes. The advantages and disadvantages of the CIP process are discussed in comparison with conventional zinc precipitation. IntroductionThe carbon-in-pulp (CIP) process involves the use of activated carbon for treatment of pulps containing dissolved precious metals, and provide s an alternative to the conventional gold recover y processes using filtration or counter-current decantation in conjunction with the Merrill-Crowe zinc precipitation process. The commercial application o f the CIP process in gold processing technology is a fairly recent development and it is of growing importance around the world.The fact that activated carbon ha s the property of adsorbing precious metals from solution was first published in 1847. In the following years , a great deal of work was carried out to develop an over-all recover y process using carbon, but all attempts were uneconomical because the loaded carbon had to be smelted to recover the gold.It was not until 1950 that Zadra, at the United States Bureau of Mines Research Centre in Reno, Nevada, developed a technique for stripping the loaded carbon using sodium sulphite-sodium hydroxide mixtures and then recovering the gold from the stripping solution by electrolysis. However, this process was not effective for stripping silver and further testwork was carried out on alternative stripping techniques. In 1952, Zadra published a paper describing the use of a hot sodium hydroxide- sodium cyanide stripping technique, which was effective in stripping both gold and silver. This paper included a description and flowsheet for the CIP process which is essentially the same as we know it today. This technique was used in the first major CIP plant, constructed and commissioned in 1973 by Hornestake Gold Mining Company. Since then there have been numerous CIP plants built in the U.S A., South Africa and Australia."

Jan 1, 1983

By Ronald C. Schimmel

In 2006, the Corus IJmuiden pellet plant produced approximately 4.6 mln tonnes of pellets. Corus IJmuiden is about to increase its pig iron production to 6.4 mln tonne HM per annum. The burden of the Corus IJmuiden blast furnaces consists of approximately 50% high basicity sinter and 50% acid pellets, both produced in-house. To enable an increased iron production, the capacity of the pellet plant needs to be raised to 5.0 mln tonne per annum. The capacity is increased by modifications to the plant layout, which were implemented during the 2006 cold maintenance stop. In addition, the composition of the ore blends is optimised to gain productivity.

May 1, 2007

By Gorzalczynski. Stan

The recent trend in underground mine developments is ?big is better?. This is most certainly evident in the mine shaft and the conveyances that operate within its compartments. Today, there are several new installations requiring mine cages that can transport up to 170 passengers. The technology in mine hoisting is advancing to address a combination of higher capacity requirements, deeper hoisting depths and faster winding rates, however, some areas of the hoist plant have not changed for the past fifty years. The most notable of these areas is the shaft compartment guide string and the conveyance mounted safety arrest mechanism. The technology in use today for the protection of passengers in a shaft conveyance from a hoist rope severance incident, remains conceptually unchanged from Elisha Otis? design of 1850. The actual retardation components, the safety dogs, have taken on several forms since Elisha?s invention with the last major design change occurring in the late 1940?s. The arrest of a free falling shaft conveyance requires that the shaft guides withstand the energy imparted on them by the safety dogs. There are some very real limitations presented by the use of wood for this application. The new hoisting era will most certainly continue to demand larger capacity equipment but also, an increased awareness toward safety.

May 1, 2002

By F. Kapeller, G. Herget

"The need for monitoring the effect of changes in ground stresses due to mining in hard rock has existed for many years. The Mining Research Laboratories of CANMET, EMR have developed a new tool which monitors with high precision the radial deformation in boreholes. The result is the Mining Research Laboratories strain monitoring system (MSMS) which uses the highly stable and very sensitive vibrating wire principle to monitor deformations in relatively large boreholes, e.g. 76 mm to 153 mm diameter.The vibrating wire is strung across a relatively large proving ring and operates at a frequency between 600 to 1800 Hz. The read-out system is based on continuous vibration.The ring is installed with a hydraulic tool and brought into contact with the surrounding rock through precisely machined and guided wedges. The resolution of the system is in the neighbourhood of 4 x 10-4 min/ Hz. The data collection can be carried out with a portable read-out unit and provisions are available for automatic data collection. Stresses may be calculated from strain readings.The system was tested in cooperation with the Centre de recherches minérales at the Niobec Mine in Quebec for the purpose of monitoring the effects of drill drift development and slope mining on surrounding ground stresses.After access was available to the site, 153 mm diameter holes were drilled for the determination of in situ ground stresses. These holes were then used to install the strain monitoring system. The effect of drill drift development and production blasting in stopes C-203-13 and C-203-15 on ground stress distribution could be observed clearly.The horizontal relaxation in the core of a pillar which occurred during mining of adjacent rooms was between 0.082 mm to 0.111 mm. Calculations of stresses from these deformations indicate that the rock material is still in an elastic condition.Roctest of Montreal has obtained a license on the manufacturing and distribution rights. A patent has been registered and CANMET will assist in installation of the MRL strain monitoring system and the interpretation of records."

Jan 1, 1989

By H. T. John

"The objective of this paper is to demonstrate how the optimum cut -off grade can be calculated for typical large tonnage openpit mines. In the examples, it is assumed that the concentrator tonnage is fixed and that there are no market restrictions. The mining rate is assumed to be variable. This is usually the situation at an operating property.ModellingA model of the ore body is required to examine alternate cutoff grade strategies. The model must be accurate in its relationship between grade and tonnage. Table I shows a typical relationship between ore tons and grade for various cut-off grades. The average strip ratio is also shown. For higher cutoff grades, the ore tonnage is decreased and the ore grade is increased. Strip ratio increases with the cut-off grade.Using the relationship between ton s and grade, and assuming a homogenous, long life orebody, a simple calculation of the optimum cut-o ff grade can be made. The objective is to maximize the present value of cash flows. For the long life homogenous orebody example this objective is satisfied by maximizing present cash flows.Cash flow is calculated by subtracting operating cost from revenue . Operating cost will increase with the cut -off grade as the strip ratio increases."

Jan 1, 1985

By Donka H. Andreeva

Gold catalysts based on different supports, titania, zirconia, ceria and mesoporous titania and zirconia, nonpromoted and promoted by vanadia in the reaction of complete benzene oxidation have been studied. XRD, HRTEM, TPR, Raman and ESR spectroscopy were applied for the characterization of the catalysts. The influence of gold on the reduction behavior, state and structure of vanadia on the surface was studied, as well as the role of supports nature on the properties and catalytic activity. A strong synergistic effect between gold and vanadia was observed for the all studied catalysts with an exception of the catalysts supported on mesoporous zirconia. In the last case the catalysts containing gold and gold-vanadia exhibit high and equal catalytic activity. The catalysts on ceria show highest and stable catalytic activity in the studied reaction among the all studied catalysts.

Oct 1, 2003

By R. D. MacEchern, M. C. Rockwell

"This paper describes the research and tests carried out to recover the readily available barite from the tailings produced by the Nystone Chemical Ltd. operation at Debert, N.S. The tailings comprised 70-80% of the original feed and contained about 20-25% Baso4 .The objective of the research, undertaken during 1982, was to produce a barite concentrate which would meet the American Petroleum Institute (API) barite requirements for use in drilling mud. Samples from the tailings pond were examined and analysed to determine the tailings characteristics.Preliminary test work was performed on the tailings samples using a Haultain Superpanner, Wilfley tables and Humphrey's spirals. The grade of the barite concentrate retrieved did not satisfy the API barite requirements.The fineness of the tailings and the fact that approximately 80% of the barite was contained in the -200 mesh (0.074 mm) size fractions, indicated that flotation of barite from the tailings might be successful."

Jan 1, 1984

By Roy EI. Durr, Glen R. Davidge

"This paper presents the results of structural analyses and full-scale destructive tests conducted on liner plate culverts. The purpose of this work was to establish a design method and evaluate the suitability of using these structures in potential roof-fall areas for a rehabilitation application in lower stress and relaxed mining environments. Field evaluation of the design is currently in progress.Theoretical ultimate resistance functions were established for two different culvert shapes and were found to be representative of their experimental behaviour. The ultimate resistance function was used to determine their plastic behaviour to a rapidly increasing deflection condition, to determine the energy absorption capacity of these structures, and to predict their response to impact loading.IntroductionThe Kidd Creek mine of Falconbridge Limited is located justnorth of Timmins, Ontario. The area under rehabilitation for which this program was developed is the 2600 level of the No. I mine. The problem of effectively securing selected drifts at the 2600 level in NO.1 mine, for access to a high-grade ore block, is key to the economics of the operation. Diamond drill test holes had indicated a loosened rock mass above the 2600 level of about 7.5 m thick in response to the extensive mining operation below this level. This level forms the arbitrary boundary between the No. I and No. 2 mines, and has extensive volumes of cemented rock fill below it and largely untouched ore above it to the 2000 level in the North orebody. The walls at that level were showing relaxed ground conditions typical of de-stress: sub-horizontal joints opening up, and peeling.Due to the ground conditions, the consequent safety risks, the high grade of the ore, the potential production delays, and the likelihood of several phases of rehabilitation, regularly used drift rehabilitation employing rock bolts, cable bolting, or shotcrete was not practical. Two options were deemed possible alternatives to suit these conditions, steel sets with blocking and lagging, and liner plate culverts with backfill. Culverts were chosen."

Jan 1, 1995

By J. R. Goode

Rare earth elements (REE) and their compounds are critical ingredients in numerous necessities of modern life including: the permanent magnets used in electric motors, generators, speaker and hard drives; high performance automobile tires; catalysts; phosphors; optical glass; etc. World production of REE in 2014 was about 110,000 t with about 98,000 t/a being “Light” (LREE) and the balance “Heavy” (HREE). Unlike other mined commodities, the majority of the LREE produced in the world is a by-product and that from a single iron ore mine in China. The balance of the LREE production comes from four REE-only mines, two in China, one in Australia and one in the USA (now on Care and Maintenance basis). The LREE operations comprise very unusual flotation processes and complex hydrometallurgical plants. In contrast, most of the HREE come from a multitude of small in-situ leach operations exploiting a single, dispersed deposit in China using hydrometallurgy alone. All of the current REE operations produce an intermediate mixed REE product that must be separated to yield the high purity, individual, REE required by the market. This paper describes the processes being used to produce LREE and HREE intermediate products and the separation plants used to make the high purity REE compounds that are key ingredients in the magnets in earbuds, turbines, and automobiles; catalysts used in the production of gasoline, and so on.

Jan 1, 2016

By D. Xia

Pt-Bi intermetallic Nanoparticles was prepared by the polymer-anchor method. The electron micrographs shows that the dimensions of particles sharply distribute in the range of about 3-6 nm. The elemental ratio of Pt/Bi in the bimetallic particles is estimated by the electron probe microanalysis method. Pt-Bi intermetallic Nanoparticles shows a higher activity for the ORR than pure Pt. No significant dependence of the oxidation currents on the rotating speed of the electrode could be observed in the presence of methanol. This clearly indicates that the Pt-Bi is inactive to methanol.

Jan 1, 2005

By M. D. Quinn

THE sand and gravel used for backfilling at the Hollinger mine is obtained from deposits in a low range of hills some three miles north of the mine, where the Company owns a number of claims. The material is transported to the mine by aerial tram. Shipments from these deposits to the Hollinger mine commenced in June, 1927, and since May, 1936, sand has been supplied also to the McIntyre mine. During 1942, Hollinger requirements were 1,700 tons per day, and 900 tons per day was delivered to McIntyre. For the past seven years production has averaged 900,000 tons annually, and total deliveries to the end of 1942 were 13,129,022 tons, of which 11,075,339 tons went to Hollinger and 2,053,683 tons to McIntyre. Some years ago, when the original pit was approaching exhaustion, new workings were opened on claims east and south of the tramway terminal. It soon became apparent that the sand varies considerably in character from place to place. The weight per cubic foot was found to range from 85 to 130 lb., and the water percolation rate from 2 to 50 inches per hour. As the mine requirement is a sand with percolation rate of 6 inches or better per hour, it was evident that in certain parts of the deposits the material was not suitable for use as backfill. As a consequence, it was decided to carry out a programme of systematic sampling of the claims in order to select the areas containing suitable material for back-fill and at the same time estimate the tonnage available.

Jan 1, 1944

By M. Moghadami

Design and construction of underground openings are associated with many uncertainties with regard to input data. In the construction process of underground openings various levels of risks exist and these affect the safety and profitability of the project. The development of underground openings can be broadly categorized into three major phases of data collection, design, and construction. A significant level of uncertainty is associated with some of the key parameters involved in the aforementioned development phases. Moreover, it is very difficult to evaluate and quantify the effects of uncertainties on the underground project construction process. Additionally, the interactions between important risk elements are typically not well understood. The intention of this study is to develop a general risk model for underground opening projects located in soils and weak rock masses. The goal of the research is to identify and quantify important geotechnical risk elements. Moreover, a weighting procedure will be proposed for the identified risk elements. Finally, all important risk elements will be assembled into a general model with emphasis on geotechnical parameters. The final objective of this study is to apply the proposed model to a real underground project scenario and verify it for actual field conditions. The proposed model, once calibrated properly, will provide a useful support tool for the decision making process.

Aug 1, 2013

By F. Schulz

NA's primary smelter has continually increased its production output in the past decade, making it necessary to improve the lifetime of the casting moulds for copper anodes. The current throughput of more than 1,100,000 tonnes per year of copper concentrates amounts to an output of about 450,000 tonnes per year of anode copper at NA's Hamburg plant. The anodes are cast on a single casting wheel with 24 anode moulds. Besides the stable chemical analyses, the reproducible geometry of the anodes is an important precondition for the success of the subsequent electro-refining process. The anode moulds are subjected to thermally-induced alternating stress and side reactions with the melt. Typical signs of wear will be shown and discussed. Different processes to produce anode moulds will be introduced and the results in terms of their lifetime and the quality of the anodes themselves will be discussed. Finally an outlook is given on possible efficiency improvements.

Jan 1, 2007

By Roger M. Nendick

"IntroductionThe stages of development for bringing a mill into production demand that a flowsheet for the process be developed at an early stage. Detailed engineering of the mill may then proceed without duplication of engineering effort on alternative processes. In the case of gold and silver mills, several process alternatives exist which must be evaluated before the flowsheet is finally fixed. The recently developed Carbon-in-Pulp process has added to this choice.Clearly, the major factor in determining the most suitable process is the amenability of the particular ore to a given treatment. Other factors that will also influence the choice are location, climate, power and water supplies, and available capital.Gold and silver milling processes can be divided into three main types:Gravity Concentration;Flotation;Cyanidation.Combinations of the three are frequently used; i.e. flotation followed by cyanidation of the concentrate, or gravity concentration in the grinding circuit with cyanidation of the classifier overflow. The following are the salient advantages and disadvantages of the three main alternatives.Gravity ConcentrationGravity concentration is suitable for free-milling gold ores, i.e. ores in which the gold is relatively coarse and free from sulphides. It should be noted that just because an ore is high grade, it is not necessarily free milling.Gravity concentration methods include jigs, shaking tables, spirals and more recently Reichert cone concentrators. All methods exploit the density difference between gold, which has a specific gravity greater than 15, depending on how it is alloyed, and the gangue, which usually has a specific gravity range of 2.7 to 3.5.A concentrate grade of several hundred ounces per ton might be produced, but recoveries by gravity alone are generally low in comparison to other methods. For this reason, gravity circuits are usually used in combination with flotation or cyanidation circuits."

Jan 1, 1983

By Christina Graf

A synthesis of colloidal gold shell particles with a silica core is described. Small gold nanoclusters were attached to the functionalized surface of colloidal silica particles. Reductive growth and coalescence of these clusters lead to the formation of a closed gold layer. By variation of the thickness of this gold layer and the radius of the shell it is possible to adjust the plasmon resonance of the gold shell particles over the whole visible and infrared region of the spectrum. The optical properties of the particles made are in good agreement with theoretical calculations for coreshell particles. Due to their low polydispersity these gold shell particles form in solution large crystals with submicron lattice constants. It is also possible to produce hollow gold shells by dissolution of the silica core. A new method to coat the silica core gold shell particles with an additional outer silica shell is also presented. This allows due to a reduction in the Van-der-Waals forces to make more permanent dried crystals and facilitates functionalization of the particles for use in various photonic applications.

Oct 1, 2003

By K. Enns, J. J. Byerley

"While thiocyanate (SCN-) is used in a number of industrial processes (production of polyacrylonitrile filaments, synthesis of agricultural chemicals and certain metallurgical solvent extraction and flotation circuits) it is recognized more as an undesirable by-product associated with ' the metallurgical industry. Thiocyanate is present at low concentrations in some waste streams from the iron and steel industry. Of particular significance is the formation of thiocyanate during cyanidation of gold and silver ores, concentrates, tailing s and residues. The thiocyanate levels present in the resulting effluents may range from a few mg/I to several thousand mg/I.At present, thiocyanate does not appear to be as hazardous in the environment as cyanide (CN-) at the same concentration although its interaction with other species and resulting decomposition of products may be unacceptable. Of course the presence of thiocyanate in the leaching circuit and ultimately in the effluent streams may add considerably to the oxidative requirments of any non-selective treatment process for cyanidation wastes.With respect to the thiocyanate as it relates to the cyanidation process, two aspects are evident. Thiocyanate forms and persists in the cyanidation circuit resulting in a ""fouling"" condition with subsequent loss of leaching activity. In order to reduce or control this problem, it is common practice for some mills to discharge daily as much as 20% of the barren leach liquor. Besides contributing to fouling of the leach liquor the formation of thiocyanate represents an irreversible loss of reagent cyanide. It is noteworthy that in some present or proposed mill practice reagent cyanide loss through thiocyanate formation may reach 50%(1). The purpose of this paper is to discus s the application of controlled electrooxidation of thiocyanate with the view of suggesting a process for regenerating cyanide from waste thiocyanate(2). The paper describes the important theoretical aspects and presents experimental data obtained for thiocyanate electrooxidation using both small and large scale electrochemical reactors. Some economic conclusions are presented."

Jan 1, 1984

By A. Tohn, K. Adham, R. Lu, D. Lemieux

"To remove sulphur, carbon and arsenic from the gold concentrates of Dundee Sustainable Technologies (DST), Hatch has designed a demonstration plant roaster using the fluid bed technology. The fluid bed was selected for its ability to maintain stable temperatures and uniform reaction conditions. Data points from a small pilot plant (operated by DST) were used for setting the parameters of the demo plant roaster.The DST demonstration plant is being built to further prove their patented gold extraction process at an industrial scale. Their gold extraction process is based on halogenation at atmospheric pressure and relatively low temperatures. Before the halogen leaching, most of the sulphur, carbon and arsenic should be roasted out of the feed concentrate.The Hatch fluid bed roaster design includes a moist feed introduction system, simple bed cooling for temperature control, and cyclone fines recirculation. The demonstration plant roaster is planned for construction in 2014, and the performance results will be presented in a future paper."

Jan 1, 2014

By R. Kwiatkowski

Agenda ? Health Canada Protocol _ Screening Level Risk Assessments (SLRAs) Contaminants Foods Exposure Pathways COPCs _ Site Specific Risk Assessments (SSRAs) In-depth, quantitative Monitoring Exposure estimates Food Issues in Environmental Impact Assessments ?Country Foods? ? Foods gathered from the project area and consumed by local residents.

Apr 1, 2005