Search Documents

By Stephen H. Chung, Kevin Atherton

The main purpose behind this preliminary study was the reduction of costs while maintaining productivity. Finding a way to achieve this balance without compromising controls on safety and quality of blasting results is of continual interest to the mining industry and of particular interest when ore of lower grade is being mined.

Jan 1, 1998

Adsorption of Starch on Kaolinite Surfaces

Sep 13, 2010

Lead Removal from Contaminated Soils with Chelating Agents

Sep 13, 2010

By S. Banisi, H. R. Iran-Manesh, M. R. Shayestefar, H. Shekarchyan

"Flotation circuit of the Sarcheshmeh copper mine processes 41,000 t/d of ore at 0.9% Cu. Chalcopyrite and chalcocite are the main copper bearing minerals which are concentrated in three stages of roughing, cleaning and recleaning. Due to major changes in the reagent addition regime, make-up balls combination, and throughput to the primary mills an increase of 2.6% (from 87.2% to 89.8%) in the sulfide copper recovery was obtained during a period of six years. In order to investigate a rather large variation of monthly recovery (i.e., from 89.0 to 91.2%) of the plant after implementation of the changes, a study was undertaken to trace mineralogically possible causes of such a behavior. During a five-month period, monthly composite samples of feed and tailings of the flotation circuit were taken. At the first stage, the polished sample preparation method and the mineral counting procedure were optimized through a detailed study. Liberation degrees and types of locking of valuable minerals in both streams were determined in three size intervals of +75, +38 and –38 microns. It was found that for both recovery levels (i.e., 89% and 91.2%), there was no significant difference in the liberation degrees of valuable minerals in the flotation feed; the average liberation degree was 57.1% with a standard deviation of 3.1%. On the other hand, in the case of high recovery level (i.e., 91.2%) there was a reduction of 15% in the amount of free valuable minerals in the tailings stream. The highest reduction was found for the -38 micron size range in particular for chalcocite. It was concluded that compared to the grinding circuit the change in the flotation circuit had the significant effect on the plant recovery increase.INTRODUCTIONThe Sarcheshmeh copper ore body contains 1 billion tonnes averaging 0.90 % copper and 0.03 % molybdenum. It is located southeast of Iran and currently processes 41,000 t/d of ore. The concentrator has been in operation since 1982. Last year, the concentrator produced 130,000 tonnes of copper and 4,000 tonnes of molybednite concentrate. An expansion to the plant which will increase the throughput by 50% is under construction and will be effective in 2003.After three stages of crushing, the ore with a F80 of 12.7 mm is fed to 8 parallel ball mills in closed circuit with cyclones to produce a product 70% finer than 75 microns. The concentrate of the first stage of flotation is reground and the tailings constitute the main component of the plant final tailings. A concentrate with an average grade of 30.5% Cu is obtained after cleaning and re-cleaning stages. At the present time, the average sulfide copper recovery of the plant is 89.8% which varies depending on the operating conditions and ore type."

Jan 1, 2003

By Robert B. Hopler

The hazards which naturally prevail in underground coal mines, always severe and unpredictable due to the loosely-consolidated strata in which coal is frequently found, are increased by the commonly-occurring combination of coal dust, methane, and explosives. It was recognized by the mid-nineteenth century that coal dust was the basic factor contributing to disastrous explosions killing hundreds of miners, and that the ignition of methane gas was often the source of the coal dust explosions. It was apparent that preventing the ignition of methane was a critical part of avoiding these disasters, and it was also apparent that one cause of such ignitions was the firing of explosives. In addition, it was found that dust explosions were often initiated by blown-out shots of explosives in the absence of methane.

Jan 1, 1996

Background Chronology 2008 Positions May 8, 2010 Summit Going Forward Say one thing and do another ??Genuine passion to see our customers succeed?, ?A passion for exceeding our customer?s expectations? Self serving actions to gain competitive advantage at the expense of the customer No single supplier or technology can manage the overall mine and its integrated operation - April 2005: Informal meeting at Toronto CIM 2004 -Unanimous interest - July 2005: Formal Calgary Meeting, developed: - Scope and vision statement , - OEM/OTM communication plan, - industry communication plan - Aug?Nov 2005: Aligned with SMART - Nov 2005?May 2006: Direct OEM, OTM communication - May ?Sept 2006: Developed baseline standards - Sept -April 2007: Developed SMART document - Sept 2007: Document distribution and request OEM OTM response - Jan ?May 2008: Acquired OEM OTM feedback and positions May 2008: Results presented to SMART and discussions on next steps

May 1, 2010

By R. Benito

This paper describes the development of a life of mine schedule (LOM) for one of the world?s largest known sedimentary Copper-Cobalt districts located in the Katanga Province, Democratic Republic of Congo (DRC). A particular feature of the Tenke Fungurume LOM schedule is the considerable number of pits/phases for scheduling, each competing to provide the best ore available to a capacity constrained process facility. This paper discusses the main scheduling objectives and constraints, data pre-processing as a scheduling aid, the mine scheduling approach, and results and conclusions.

Jan 1, 2011

By G. Denton, P. den Hoed, A. Luckos

The potential application of fluidized beds in several sectors of the ferroalloy industry is promising. They can be used in the direct reduction of iron ores to produce a feed for steelmaking, in the reduction of manganese dioxide to produce a lesser oxide for feeding to smelters, in the preheating of chromite for the production of ferrochrome, and in the calcining and pre-reduction of nickel laterites for the production of ferronickel. This paper discusses the potential of fluidized beds in theses processes and highlights the advantages of the technology over other technologies, such as rotary kilns. Two primary advantages?(1) that fluidized beds can treat fine materials and (2) that fluidized beds can be integrated with smelters in a way that allows for more efficient use of energy?may well see the technology gain prominence as more deposits of lower grade are mined and industries strive to use their resources more efficiently. In discussing the potential of the technology in the ferroalloy industry, this paper focuses on the application of fluidized beds in the smelting of chromite, nickel laterites, and manganese ores. Central to the successful operation of this technology is a knowledge of how particle properties influence the behaviour and design of fluidized beds.

Jan 1, 2007

By Vinay Kumar

The present investigation describes R & D studies carried out for recovery of copper from the sulfate solution expected from the leaching of e-wastes in presence of minor constituents such as cadmium, zinc and nickel using solvent extraction process. In order to extract copper in continuous mode in mixer settler unit (MSU), basic studies have been made to optimize the experimental condition using 5%LIX84 in kerosene. Subsequently, the solvent extraction of copper was made in MSU maintaining leach solution flow rate 4.0 L/h and A/O ratio 1. The results showed complete extraction (~97%) of copper in three stages at A/O ratio 1 from the aqueous solution containing 1.98g/L Cu at pH 1.91 in presence of impurities. Loaded metal was completely stripped after scrubbing with 10% sulfuric acid in two stages. The stripped solution could be used for metal/ salt recovery by electrolysis/ crystallization.

Jan 1, 2010

By Todd Wanless

This paper addresses the challenges experienced by the designer and three government agencies during implementation of major improvements for the Turkey Creek Tunnel in Kansas City, Kansas. The tunnel serves as a vital stormwater conveyance system for upstream flood control. Major structural deficiencies were identified within the tunnel including complete loss of sidewall and invert. Without immediate attention, complete loss of the tunnel arch could lead to blockage and extensive remedial repairs under difficult conditions. Considering that tunnel flows must be maintained during construction, a phased design and construction process has been implemented to expedite stabilization of the erosion cavities followed by tunnel liner repairs.

Jan 1, 2008

By R. J. McLeod

"CONTROL STRATEGYThe Lake Dufault Division of Falconbridge Copper Limited has been concentrating a complex copper zinc ore since late 1964. An ARL X-ray on stream analyzer was installed in 1966 for process control. A Digital Equip-ment Corporation PDP8 was added in 1968 for more complete control. To improve the system the computer was exchanged for a Moded PDP-81 in 1971.The new computer is time sharing with 8K core memory and 32K disc storage. A new interface was installed to accommodate 14 X-ray streams and additional analog signals for process control. The system gave us additional capacity and flexibility to make changes in operating programs and control strategy while on line. As the computer is used for process control a modified focal language was chosen as the operating language for ease of operation. This language is more suitable for process control than for statistical work.The main components of the control system are(a) Computer(b) Interface(c) Production Control X-ray Quantometer(d) Teletype terminals(e)Reagent feeders(f) Sample SystemThe operation of the system consists in the computer selecting the various streams to be analyzed by a PCXQ Quantometer. When the flowing sample is presented to the X-ray the intensities of the various elements are read by the computer from analog to digital converter, the assays are then computed. From the tonnage and assays the computer is programmed to determine the amount of reagent added to various parts of the circuit. The computer drives the feeders via the interface for the required amount of reagent. After following a certain sequence the computer prints out the performance and control data on an ASR35 Teletype. The data is printed out approximately every seven minutes. Any des¬ired changes in the program or strategy can be made during operation via an ASR33 Teletype connected to the computer."

Jan 1, 1973

By B. J. Arnold, N. Terblanche

The features of the ‘Turbo’ froth flotation column will be discussed, including the double aeration system that improves flotation yield while not sacrificing grade, the internal launder system, and the unique feed/tailings sump that evens out flow to the flotation column preventing upset conditions. Results from various test programs and installations will be presented.

Jan 1, 2001

By Lathrop E. Roberts

The opinion is general among smelter operators that magnetite formed in the converter and reverberatory furnace has much to do with the loss of copper in the slag. Its action appears to be due in part to its relatively high infusibility, chemical stability, and specific gravity, as a result of Which it tends to form a layer of highly viscous "magnetite mush" between slag and matte. Particles of matte which might otherwise settle out of the slag are unable to pass through this layer. Maier and Van Arsdele have shown that the inclusion of grills of matte in the slag is also at tires very probably due to chemical reaction between magnetite and the constituents of the matte. In smelter control and in any laboratory study of slats the determination of magnetite is therefore a matter of some importance. The difficulties in the ray of making such a determination with any accuracy are rather obvious. Iron may occur in slag as ferric oxide, magnetite, various intermediate oxides, sulphides, silicates, as free metal, and in solid solution of several of these substances. Even if only the total iron content is to be determined, accuracy can be obtained only by painstaking and time-consuming separations from interfering elements. The determination of ferrous, ferric, and free iron in the presence of each other is a difficult matter under the most favorable conditions, and when present in a slag the difficulties are increased by the refractory nature of the sample, by the presence of sulphides, and by such elements as vanadium and molybdenum.

Jan 1, 1931

By Lathrop E. Roberts

[The opinion is general among smelter operators that magnetite formed in the converter and reverberatory furnace has much to do with the loss of copper in the slag. Its action appears to be due in part to its relatively high infusibility, chemical stability, and specific gravity, as a result of which it tends to fern a layer of highly viscous. "magnetite mush" between slag and matte. Particles of matte which might otherwise settle out of the slag are unable to pass through this layer. Maier and, Van Arsdale4 have shorn that the inclusion of prills of matte in the slag is also at times very probably due to chemical reaction between magnetite and the constituents of the matte. In smelter control and in envy laboratory study of slats the determination of magnetite is therefore a matter of some importance. The difficulties in the ray of making such a determination with any accuracy are rather obvious. Iron may occur in slog as ferric oxide, magnetite, various intermediate oxides, sulphides, silicates, as free metal, and in solid solution of several of these substances. Even of only the total iron content is to be determined, accuracy can be obtained only by painstaking and time-consuming separation ions from interfering elements. The determination of ferrous, ferric, and free iron in the presence of each other is a difficult matter under the most favorable conditions, and linen present in a slag the difficulties are increased by the refractory nature of the sample, by the presence of sulphides, and by ouch elements as vanadium and molybdenum.]

Jan 1, 1931

The selection of the mining fleet can have as much of an effect on the efficiency and effectiveness of an operation as the mining method. This is not to say that inefficiencies are only attributable to inappropriate equipment selections, these aspects have many factors but are not the subject of this paper.This paper will give an overview of equipment selection processes that have been utilised to date. It will also look at the increase in application of study programs/simulations from an aspect of accuracy, as well as the importance of enabling the analysis of multiple sensitivity scenario planning. An aspect that is increasingly important in project planning with commodity market movements.Another aspect that is increasing in popularity is that of automation, what effect does this have on equipment selection? What additional aspects need to be taken into consideration when assessing Automation of equipment from the beginning of a project as well as introduction into an operating mine?Once the selection process has been finalised and equipment implemented, how do we, as an industry, 'close the loop' through analysis of estimated versus actual equipment application?

Dec 6, 2010

By A. B. Fox, R. P. Thackray, K. C. Mills

The role of mould fluxes in continuous casting is reviewed. The main functions of the flux are described and the importance of the flux in providing lubrication and the right level of heat transfer between the shell and the mould is described. The major problems of longitudinal, transverse and star cracking, gas and slag entrapment and deep oscillation marks in the steel product and ?sticker breakouts? are analysed. The important physical properties of the flux in combating these various problems are identified. Physical property data for the fluxes are given.

Jan 1, 2004

By Shane McDonald

Australia produces approximately 84 million tonnes of coal per annum from 30 longwalls in New South Wales and Queensland, operating at an average depth of around 300m. Industry trends and expectations place increasing emphasis on the reliability of these operations; for example, the current average face width is 245m and this is expected to increase to approximately 270m by 2010. In recent years, Beltana No.1 Mine has consistently been Australia?s highest longwall producer, with ROM output of 7.2Mt in YEJ2007. Strata management has become a key feature of the operation of Australia?s longwall mines, as a tool to manage variances in the geotechnical environment. This involves an understanding of the impacts of the geotechnical environment on ground behaviour and the implications for mine design, stability and associated support, interaction and horizon selection. The anticipated ground control impacts of these factors form the assumptions that drive the format of plans specifying both triggers and actions, with quantified, monitoring-focussed experience used to refine the plan in a continuous improvement (ie ?plan-do-check-act?) process. This paper summarises the Beltana No.1 Mine strata management methodology and experience to-date.

Jan 1, 2008

By E. S. Yan, R. Graley

"The StackCell was developed to overcome the engineering and design challenges that are commonly associated with existing flotation technology such as pneumatic, self-aspirating cells, mechanical cells, and flotation columns. These challenges include high energy consumption, large floorspace requirements, and size. They are most evident when designing systems to process streams containing a high volumetric flow rate coupled with a significant float yield. Unlike many metalliferous and industrial mineral applications, fine coal flotation circuits are typically characterized by feed streams containing a low solids content (<5%, by weight) where up to 85% of the feed can report to the product launder. With input from major engineering houses and end-users, the Eriez Flotation Division (EFD) developed the StackCell technology with the goal of providing an additional flotation option for end-users. This technology was designed specifically to overcome these challenges by providing an efficient method of separation in terms of metallurgy, but also with respect to equipment size, energy consumption, and installed costs. Besides being placed in tandem with existing cells to provide cost-effective supplemental capacity, this technology can be installed in a stand-alone arrangement as recently demonstrated at Patriot Coal’s Kanawha Eagle preparation plant. This manuscript provides an understanding of the underlying fundamentals of this new technology and presents data from Kanawha Eagle in addition to other industrialscale installations.INTRODUCTIONOver the past decade, column flotation has continued to gain acceptance as an alternative method for recovering fine coal due to superior metallurgical performance as compared to mechanical flotation cells. This point has been proven on numerous occasions by comparison of plant flotation data with the release analysis separation curve (Dell et al., 1972). Data from a release analysis test approximates the ultimate flotation response of a coal sample. In North America, a number of investigations have been published that document bottom-line improvements achieved using column cells (Luttrell et al., 1999; Kohmuench et al., 2004; Baumgarth et al., 2005). According to these reports, the benefits are derived from an overall increase in plant yield that can be achieved due to the improved product grade in the flotation circuit. In particular, the application of wash water to a deep froth utilized in column flotation minimizes the nonselective recovery of high-ash ultrafines that are hydraulically entrained in the froth by conventional flotation machines."

Jan 1, 2013

By E. C. Tarpley, H. M. Cooper, R. F. Abernethy

"INTRODUCTION The determination of moisture in coal is an empirical test, because the time, temperature, and equipment are specified. The essential features of the equipment, and details of the procedure are given in A.S.T.M. Designation: D271-44 5/. According to the specifications, the following features should be incorporated in the equipment used:1. Oven must have uniform temperature in all parts.2. Oven must be constructed with minimum of air space.3. Oven must have means of changing the air two to four times per minute.4. Air must be dried over sulfuric acid (sp. gr. 1.84).The analytical procedures governing most of the nation's coal purchases are those given in A.S.T.M. Standards referred to above. These standards are general and of such scope as to cover all ranks and types of coal. In cases where only the moisture is required, a faster method than the standard procedure is desired.The semi-automatic moisture tester manufactured by the Brabender Corp. has proved itself in many industrial processes where the rapid estimation of moisture is of vital importance. With the approval of A. C. Fieldner, chairman, A.S.T.M. Committee D-5, and through the courtesy of Lowell Malan, chief chemist, United Electric Coal Companies, who loaned the tester, tests were made to determine the feasibility of using this instrument to determine the moisture in coal."

Jun 1, 1948

By Elizabeth Varghese, Sanket Rawat, Prachuryya Kaushik, Ravi Kant Mittal

"Geo5 Software is gaining popularity worldwide due to its expediency in analysis and design of pile foundation. The analysis is based on various theoretical, empirical and semi-empirical methods available in existing literature and various country standards. Moreover, the ultimate resistance of pile in the software is based CSN 73 1002, Fellenius method, NAVFAC DM 7.2 and Tomlinson method. Due to the specificity in calculation of ultimate resistance, it becomes necessary to validate the results arrived using the software for better accuracy. Furthermore, the above-mentioned methods are not necessarily popular in every design offices. Therefore, an attempt has been made to predict the efficiency of Geo5-v15 software to analyze the pile foundation by comparing it with the results obtained using the analysis based on Indian Standard IS 2911:2010, performed with spreadsheet specifically designed for the same purpose. The accompanying outcome of the comparison and several shortcomings found in the design part associated with the software has been highlighted in the later part of the paper. Besides, the optimization tool present in the software is also described for the more efficient and economic design of pile foundation, hence contributing as practical aid to structural engineers.INTRODUCTIONThe analysis of individual pile foundation and pile in groups can be said to include the three main important parameters – Ultimate bearing capacity, Settlement and Structural Design. The first two parameters are to be evaluated to check the reliability of foundation against ultimate limit state and serviceability limit state. The third parameter includes the analysis of pile against both horizontal and vertical load. This parameter mainly intends to evaluate the size of foundation and the amount of reinforcement. Geo5 is a software which can expediently compute the above mentioned three parameters just by the mere input of the necessary factors. The ultimate bearing capacity analysis in Geo5 is based on various theoretical, empirical and semi-empirical methods available in existing literature and various country standards depending upon the drained and undrained condition of soil (Bowles, 1968; CSN 73 1002,1987; Felenius,1991; NAVFAC DM 7.2,1984; Tomlinson,1977). However, the method mentioned in IS 2911 (2010) is not the same and have slight variations in way of evaluating the parameters which affect ultimate bearing capacity. Therefore, it becomes necessary to evaluate the efficiency of Geo5 with respect to the value of ultimate bearing capacity and therefore, asserting the confidence in the software based method for the convenience of the designs in Indian Scenario. The present study aims to evaluate the efficiency of Geo5 v-15 software in predicting the ultimate bearing capacity of pile foundation. The results of the software are compared with the bearing capacity calculated using IS 2911 (2010) with the help of excel sheet. Moreover, as the software is frequently put under revision, therefore a comparison of this version has also been made with the latest version of Geo5 (2017) to check whether the latest revision has accounted for the discovered shortcomings. The design steps performed in the software is also shown. As Geo5 make use of IS 456 (2000) for the design purpose, hence it can be considered as reliable with respect to the estimate of the third parameter. Furthermore, the optimization process is also shown in the later part of the paper to emphasize the simplicity of the software in economizing the design cost."

Jan 1, 2017