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By J. H. Van Reenen, H. Thiele, C. Bergman

For some time spirals have been the process equipment chosen to recover metal in the size range 0.15 to 3mm from ferrochrome and silico/ferro manganese slags. Recoveries of metal obtained using spirals are usually about 70%. Spirals are also difficult to control. By combining a novel gate on the Apic pneumatic fines jig with the recently developed Apic classifier, metal recoveries of 76% and grades of over 90% have been obtained for FeCr and SiMn slags in the size range 0.15 to 3 mm. The paper compares classifier operating performance and costs with those spirals for FeCr and SiMn metal recovery from slags. The classifier technology can also be applied to chromite and iron ores and coal fines.

Jan 1, 2004

The Institute is custodian of funds for support of numerous gold medals and prizes and has representatives on boards awarding still others. Details regarding the Institute Awards are given be- low. The Institute is represented on the boards of the John Fritz Medal, the Hoover Medal and the Washington Award, in connection with the three national societies of Civil, Mechanical and Electrical engineering; and, also, in the case of the Washington Award, with the Western Society of Engineers. The Institute is represented with these four societies on the committee in charge of the Alfred Noble Prize.

Jan 1, 1932

By L. B. Kirk, A. R. Kirk

At New World, Au-Cu-Ag mineralization occurs in stratiform car-bonate-hosted, massive sulfide-iron oxide, and skarn-replacement deposits. Regional pyritic-alteration, local massive sulfide mineralization and mine wastes generate acid drainage within the district. Water quality improves down gradient through dilution and mixing of acid and metal-rich mine water with bicarbonate-rich, low-metal surface and groundwater, and precipitation of metal-rich ferrihydroxide phases. Natural deposits of ferricrete indicate that pre-mining ARD has occurred, providing important clues to pre-mining water quality. The geoenvironmental model identifies the Cu-skarn mineralization as the primary target for ARD management. Closure success will be limited by the geoenvironmental nature of the natural mineralization.

Jan 1, 2004

A concept gaining attention among rock mechanics researchers in studies of soil-structure inter- action is the use of compressible packing between the structure such as tunnel lining and the soil or rock. Lester H. Gabriel, provided information about work on this concept at the II Symposium on Rapid Excavation, October 16-17, 1969, Sacramento State College, Sacramento, Calif. It is well-known that loads transmit their effects to those locations which deform least. Traditionally, the question to be answered by the structural engineer is how rigid the structure ought to be. The stronger the structure, the more resistant it becomes to deformation. If it is more rigid than the surrounding strata, the structure acts as a pillar, focusing load on itself. However, if the structure is less rigid than the surrounding strata, blocking or packing between the structure and the enclosing material facilitates the formation of soil or rock arch. The object then is to design and build structures such as tunnel linings, which harness the advantages of carefully planned small movements. Tests on plaster cylinders imbedded in granular sand and loaded were compared to those of plaster cylinders protected in sheathing of polyfoam rubber. The compressible sheath permitted support of up to ten times greater loads Gabriel, Lester H., "Principles of Soil-Structure Interaction Applied to Tunnel Linings." Hecla Mining Co. has successfully used shotcrete with substantial cost savings for ground support purpose. To date, the use of shotcrete in Hecla's operations has been limited to openings where long-term high quality support was required, in exceptionally difficult ground, and to a limited degree in stope support. Experience with both the wet and dry process indicated that the latter was better for their applications. The availability of effective accelerators which reduce losses from rebound, give high-early strength and permit placement in wet conditions, led to this conclusion. The gross cost under such conditions as those at Hecla, including rebound losses and overshooting, is estimated by Hecla to be $51 per cu yd.

Jan 12, 1969

By Ren G. Dong, Jay Kim, Daniel E. Welcome, Won Joon Song, Charles Hayden

Prolonged, extensive exposure to hand-transmitted vibration could cause a series of vibration-induced disorders in the vascular, sensorineural, and musculoskeletal structures of the human hand-arm system, which have been collectively called hand-arm vibration syndrome (HAVS).1 To assess the risk of HAVS the international standard ISO 5349-1 (2001)1 recommends using the root-mean-square (rms) acceleration of the measured vibration with a frequency weighting. While a few epidemiological studies have reported results consistent with the predictions made according to the recommendation, many other studies have reported results with large discrepancies.2 This may be partially attributed to the time-averaging effect involved in calculation of the frequency components, especially for impact type tools. Because the spectral characteristics of impact tools change dramatically with time, a time-frequency (T-F) analysis can provide better characterizations of such highly transient vibrations. The analytic wavelet transform (AWT) is an ideal T-F analysis tool because it possesses the advantages of both the Fourier transform and the wavelet transform.3 The objective of this study was to explore the application of the AWT method for characterizing the impact tool vibrations and assessing their exposure risk. Methods Five tools (two chipping hammers, two riveting hammers, and one concrete cutting saw) were used in this study. The saw vibration was measured when it was used to cut a section of road pavement during a repair. The vibrations on the other tools were measured by the procedure specified in ISO 8662-2 (1992).4 A sampling rate of 16,386 Hz was used in the measurement. The AWT and Fourier analysis were applied to these signals and to identify their characteristics. Results Figure 1 compares the T-F characteristics of the accelerations measured from the relatively steady concrete saw and a riveting hammer. The frequency weighting specified in ISO 5349-11 was applied in the calculations. The comparison clearly shows that the two tools have completely different T-F characteristics.

Jan 6, 2006

By L. Rintala

The design of a hydrometallurgical process starts with the analysis of the raw materials to be treated, for example mineralogy, chemistry, deposit size are analysed. Based on this information suitable unit processes for pre-treatment, leaching, solution purification and product recovery are selected. Typically, process design for the new ore deposit relies on laboratory tests such as pre-treatment and leaching experiments. The experimental work is the most time consuming and expensive part of the process design. Reducing the number of experiments would shorten the time of designing a new flowsheet or development of new process technology. A large amount of information is available about the hydrometallurgical experiments and the amount is increasing continuously. For example, word search using ?hydrometallurgy? from Scopus database results in over 4 000 publications with the word in title, abstract or keywords. This number consists of 2 500 articles, 900 conference papers, and 90 reviews since 1972. The number of hydrometallurgical publications per year has increased from 13 in 1972 to 150-200 in the last few years. The objective of this study was to analyze how detailed data of experiments about the gold extraction is published and how that data could be exploited more effectively when designing hydrometallurgical processing for new ore. The leading idea is that similar ores should have the similar response in leaching. If the published information was used more efficiently, the amount of experiments would be reduced. More than 200 cases of experimental data of gold leaching have been analyzed for this study. There are over 30 factors that could be used in comparison when selecting process alternatives, but challenging fact is that not all these factors are documented in all publications. Results show that the usefulness of the published data in the development of hydrometallurgical flow sheet for gold using decision-support tools is not that straightforward. The quality of the published information about gold extraction varied between the publications and the descriptions of the raw materials, experimental arrangements and results were often missing details. Methods to normalize the data for description of the cases and a system to describe different features unambiguously are needed. Keywords: refractory gold, host mineral, leaching, data analysis, case-based reasoning

Sep 1, 2012

Editor?s note: Each year, Mining Engineering features an industrial minerals review. Several people put in a fair amount of time in developing the material for this issue, all the while doing their own jobs. Thank you to the industrial minerals annual review editor, to the Industrial Minerals and Aggregates Division technical committee chair and vice-chairs, and to the authors of the individual commodity profiles. Jim Norman, member SME, of Tetra Tech, is the industrial minerals annual review editor. Rajesh Raitani, member SME, of Cytec Industries Inc., is chair of the Industrial Minerals and Aggregates Division?s Technical Committee. The technical Committee vice chairs include: ? Vishal Gupta, member SME, of FlSmidth, Agricultural Materials. ? Candace Trimble, member SME, of Oil- Dri Corporation of America, and Bradley Van Gosen, of the U.S. Geological Survey, ceramics and refractory materials. ? Stanley Krukowski, member SME, of the Oklahoma Geological Survey, chemical raw materials. ? Russell Winn, member SME, of R.E. James Gravel Co., chemical raw materials. ? Justin Zdunczyk, member SME, of Plum Creek, construction materials. ? Jerry Gauntt, member SME, of Golder Associates, fillers and pigments. ? Michael Cheshire, member SME, of Los Alamos National Laboratory, sorbents, filters and process aids. ? Rajesh Raitani, member SME, of Cytec, Industries Inc., specialty minerals. Their help makes possible this June industrial minerals issue. On behalf of ME readers, the editors thank them.

Jul 1, 2013

By S. Behl

A major limitation in developing successful selective flocculation schemes is the difficulty encountered in adsorbing the polymeric flocculant only on the desired substrate. In this paper a correlation between selectivity of flocculant adsorption and separation efficiency is outlined and a potential technique to achieve selective adsorption of flocculants is discussed.

Jan 1, 1992

By Howard F. Puariea

This paper is one of a series describing methods and costs of recovering sand and gravel from alluvial deposits in the United States and deals directly with the methods employed by the Portland Gravel Co. in operating a clamshell dredge on the Willamette River near Portland, Oreg., and a pump dredge on the Columbia River near Vancouver, Wash. These papers are designed to disseminate technical information regarding the methods used. The cost tabulations represent local expenditures only and not total production costs. It is recognized that publication of total costs may in some instances cause embarrassment to individual producers as well as to the industry as a whole. On the other hand operating costs are essential to the technical discussion and study of methods employed. The attention of the reader is specifically called to this differentiation in order that no misunderstanding of the scope of the cost tabulations shall ensue.

Jan 1, 1932

By Clyde Wyman

THERE has always been a question as to the extent to which oxidizable alloys might he recovered from charged scrap in the, acid electric furnace. While qualitative information was not lacking, the quantities that might be recovered and the conditions best suited for such recovery were not clearly defined. The present investigation was carried out to determine the efficiency of alloy recovery from residuals contained in the bath, especially in regard to the recovery of vanadium. A series of 24 heats was produced at the Burnside Steel Foundry Co., including medium manganese-molybdenum-vanadium, manganese-chromium, and grade B steels, in which vanadium recoveries from the residual vanadium were investigated. Recoveries of other alloys were also studied from the accumulated data. These heats were produced in a 5-ton acid-lined electric furnace. The analysis of metal and slag samples and the micrographs were prepared by the Research Laboratories of the Vanadium Corporation of America. In addition to the vanadium contained in the scrap charge, ferrovanadium was added to the charge and to the molten bath to bring the residuals up to the desired level. Vanadium pentoxide (V2O5) in one series of heats was added to the bath after meltdown, for the same reason. In addition to the general furnace practice, the slags of these various heats were treated with coke breeze, Ferrocarbo-S (silicon carbide), and aluminum dross to determine the effects of different reducing agents upon the alloy recoveries and upon the final product.

Jan 1, 1947

By K. R. Van Horn

RESIDUAL stresses in metals operate under a cloak of mystery, as they have neither been seen in the laboratory nor detected by means of the microscope. In spite of their phantom-like nature, they frequently exert metallurgical effects that cannot be ignored. In some cases the results have been detrimental, causing rejections or premature failures, but frequently the effects have been highly beneficial to the producer or consumer of metal products. First, however, what is a residual stress? When a metal is plastically deformed by bending, rolling, pressing, or by a phase transformation or precipitation from solid solution, or by a sharp temperature gradient resulting from nonuniform cooling, quenching, or welding, it remains in a state of strain. The strains or strain gradients produced by such operations and retained after all external forces are released are known as residual strains, and the accompanying stresses as internal or residual stresses. Many defects or failures in metal products have been ascribed to residual stresses, sometimes erroneously, because there was no other apparent explanation after the usual metallurgical tools of diagnosis had been applied. For example, during World War 11, the forged aluminum alloy aircraft cylinder head in the reciprocating engine began to replace the cast head with the familiar cooling fins. The fins were machined in the solid forged head by an ingenious milling operation. One plant reported an epidemic of excessive distortion during the delicate high-speed milling. A thorough examination revealed that the composition, heat treatment, mechanical properties, and metallurgical quality of these heads were comparable to those of forgings that machined satisfactorily. It was then claimed that the cause of the machining difficulties was connected with residual stresses resulting from the quenching during the solution heat treatment. An elaborate stress analysis actually demonstrated, however, that the magnitude of residual cooling stresses was lower in the cylinder heads which machined poorly than in those which were satisfactory in this respect. Subsequent tests proved that the machining problems in this case originated from variations in the tools and tool design. Sources of Residual Stresses in Metals Residual stresses are of two origins—mechanical and thermal. Thus, stresses may be produced in a metal by any cold-working process. The distribution and magnitude of these mechanically produced stresses can be calculated in a satisfactory, although approximate, manner for such simple cases as bending, torsion, and expanding of tubes. However, most manufacturing processes are too complex, and the original stress-strain relations in the products are not sufficiently known to permit calculation of the resulting residual stresses. Also, a specific process, such as wire drawing, may vary in complexity or uniformity of working, and large or small residual stresses may result, depending on the conformation of the dies and other features of the working process. Neither substantially unidirectional deformation, such as can be imparted by stretching a metal product having essentially the same mechanical properties throughout the cross section, nor deformation

Jan 1, 1954

By Elaine Araújo

Since the ancient times, clays were used as decolorant material for various types of oils. These clays were called ?decolorant clay?. They have the property to decolor dye materials present in mineral oils, plants and animals. Biofuel is a fuel derived from biomass of live organisms. As biodiesel is produced from renewable sources, the generation of employment due to industrial scale production may cause a reduction in the dependence on foreign diesel importing, as well as the reduction of air pollution by the addition of biodiesel to diesel. This study aimed to develop a technological process to decolor post- consumption oil to be applied as biofuel. The results were characterized by techniques of XRD (X-ray diffraction), X-ray fluorescence and FTIR (Fourier Transform Infrared). It was observed that the post-consumption oils presented a higher decoloration result after treatment with the Brazilian clay.

Jan 1, 2009

"A growing public awareness of work-related diseases such as pneumoconiosis and the impact of this awareness on legislative bodies and on the skilled labour market are reasons why the Canadian mining industry must consider dust control of top-drawer importance. Measurements and standards related to the hazard are necessary to control a dust situation and to avoid excessive risk. The author discusses some of the methods of measurement, standards proposed and terminology used in this developing technology. The purpose primarily is to give a better understanding of the basic advances achieved by those who have applied current knowledge with a measure of success."

Jan 1, 1972

By D Sinclair

Sustainability will become a more stringent issue in mine planning over the next 40 years. The evidence of this is apparent in State and Commonwealth government policies now emerging in respect to water, green house gases, waste and other process emissions. The mining industry has developed policies such as æEnduring ValueÆ, which go some way towards establishing a framework within which mining can continue to be an underpinning strength within the Australian economy. However, the demands of new policies are directed at extending sustainability in ways that will change the way in which projects are implemented. This paper examines the nature of new policies aimed at water, energy and emissions, considering examples of where mining practices have or may change in order to meet new objectives in resource efficiency. Important issues will, as always, be the international price competitiveness of the mineral resources being produced but, where this is now devolved around mining and processing costs, these costs may in the future be strongly correlated to the nature and cost of local energy resources compared with those in Australia, the ability to mitigate and minimise water resource use and environmental impacts deriving from emissions and the veracity of competitor nations in meeting the same standards of performance in resource efficiency usage and in emissions control. As these systems bed down internationally mining in Australia will need to concentrate, amongst other things, on finding higher grade orebodies and on better technologies to release the value of lower grade ores. For our mining industry to remain strong, greater expenditure will need to be focused on these objectives. Finally, it will be important for the industry to remain vigilant and proactive in directing government policy development to ensure that practical objectives in mining are not curtailed unnecessarily through ignorance of mining market precepts developed over the centuries of mining operations.

Jan 1, 2008

(Under. this heading will he published notes sent to the Secretary of the Institute by members or other persons introduced by members.) Member; age 31, technical graduate, 8 years' experience in copper and nickel mining, desires to make a change. No. 480. Member, age 34, married, 16 years' experience as railroad construction engineer and as superintendent of iron, chrome and manganese mines. Especially successful in rush construction work and development of new mining properties. No straight salary proposition will be considered. No. 481. Member desires change of position. Four years experience in flotation, cyaniding, and mill design and construction. Married, technical graduate. No. 482. Member, age 33, married, graduate Columbia School of Mines. Nine years' experience as engineer and mining and oil geologist; experience in Mexico, Peru and Siberia. Speaks Spanish and Russian. No. 483.

Jan 9, 1918

By Luis Yacher

CONTAC Engineers is a Chilean based company which works on process control and automation, principally for the minning industry. Jointly with other local and international engineering firms, CONTAC has participated in most of the last expansion and modernization plans being carried out at the Chilean pinning industry. At presente, CONTAC is involved on a research and development plan for the design and implementation of new instrument and process control procedures for mineral process automation. One of these efforts is the design of an ore size analyzer for coarse ore being transported over a conveyor belt. A feasibility and prototype study was made at a SAG Mill Plant and currently a high resolution, high speed analyzer is being developed. It will became available on early 1986.

Jan 1, 1986

Active and abandoned mine sites can be an irresistible- - and sometimes deadly - - draw for outdoor enthusiasts, particularly children and young adults. Despite repeated warnings, posted signs, and fencing, tragedies involving accidents on active and abandoned mine property continue to make headlines, especially with the arrival of warmer weather and the summer months ahead. Over the last few years, there have been dozens of tragic incidents involving children and adults ventur­ing onto active and abandoned mine property. They include: A 16-year-old youth suffered fatal injuries after his all-terrain vehicle became airborne in an accident at a gravel mine near Albany, New York. A young boy was electrocuted when he contacted a high-voltage power line while sliding down a stockpile at a sand and gravel mine in Grand Island, Nebraska during its off-shift hours.

Jan 1, 1999

By Mucella Ersoy, Nese Celebi

Management Information System (MIS), is a system using formalised procedures to provide management with appropriate information to make timely and effective decisions. Before developing MIS, first functions of the organisation should be defined and grouped into subsystems. After determining the information required and produced by each system and interaction between subsystems, the related data resources should be structured into a series of databases and files. In this study, the MIS developed for Soma Open Pit Mines, Turkey is described in this respect. First, analyses of the existing system including user requirements and scope of the system are given. Then the designed information system, its subsystems, interaction between subsystems and system structure are presented in detail.

Jan 1, 2002

By Gerard P. Hand

The use of graphite in industrial applications is one of the oldest in the world. Yet, it is one of the fastest-changing technologies today. Graphite was first used centuries ago in developing writing instruments and as a raw material in crucibles used in melting metal. Today, graphite is used in some of our most demanding industries. These include aerospace, electronics and automotive applications. Graphite usage has historically been split between the natural and synthetic forms. Figure 1 shows the breakdown of natural graphites and synthetic graphites used. The usage of natural graphites and synthetic graphites is split fairly evenly, although the applications are quite different. Figure 2 shows the breakdown of applications using natural graphite. The largest application is the refractory industry. This includes refractory brick and plastics, crucibles, shrouds and other refractory parts. This main application uses roughly 50% of all natural graphite. The refractory industry is an important application for natural graphite. However, the refractory markets have been struggling for several years. As demonstrated in Fig. 3 (Semler, 1996), the production of refractories in tons per year has declined by more than 32% during the last 25 years. Refractory prices have actually risen on a dollar per ton basis during that same period as the product mix has shifted to the value-added side. Raw material and production cost increases, inflation and other related costs have kept profitability at low levels for the industry. Furnace linings that once lasted 1,000-2,000 heats now last 8,000-12,000 heats. This means that tonnage requirements have gone down and quality requirements have gone up for graphite suppliers. Therefore, new opportunities and applications must be developed if the graphite industry is to grow. Synthetics are the other major forms of graphite. There are two forms of synthetic material currently used. One is the traditional type. It is made from the turnings of graphite electrode production. The second was developed in the mid-1970s in response to a shortage of conventional synthetic graphite. This occurred by a breakthrough in thermal technology. This new technology purifies, desulfurizes and graphitizes petroleum coke on a continuous basis at temperatures of more than 2,500° C (4,532° F). This product is called desulfurized petroleum coke (Desulco). It now accounts for about half of the synthetic type material used in the United States. Figure 4 shows the breakdown in the use of synthetic types of material by application. The largest requirement is for use as a carbon addition in iron and steel. This is followed by alkaline batteries and friction materials. Current technological opportunities New opportunities for graphite products are now being developed. These new areas are made possible due to the advances in graphite thermal technology. The ability to purify and modify graphite and carbon products is the key to future growth in the graphite industry. New, higher-purity, more consistent graphite products are leading to enhanced performance in current applications. They are also opening the door to new applications.

Jan 1, 1997

By A. A. Hejja

The first part of this study deals with the importance of surface tension of slags produced in the smelting of sulphide concentrates. Theoretically the method of determining the surface tension of slags was laid down by Boni and Derge. The values obtained experimentally for a series of main oxide components were grouped into a useful correlation incorporating experimental constants for the relevant oxides present in the slag, some of these giving the surface tension value for the particular slag. These estimated values were coupled with or incorporated into the slag viscosity plots to show the correlation between the two factors. This is also important from a refractory attack point of view in the furnace operation. In the second part an attempt is made toward the optimisation of slag composition relevant for electric furnace smelting processes. Using the knowledge of the viscosity and electrical conductivity of the slags at the temperature of furnace operation, the mode of optimisation is based on correlations which utilize the trend of the mostly parabolic plots of viscosities and conductivities. The results obtained by this method agree well with the optimum slag compositions being used in established operations derived from years of practical experience for various slags used in the furnaces. However, due to extensive turbulence in suspension and gas injected bath smelting processes, the outlined methods cannot be used for these processes. Also great caution should be exercised in their application for three electrode circular furnaces with separate slag cleaning.

Jan 1, 1997