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By Glastras M. V

The presence of arsenic in solutions which result from the processing of many sulphide minerals leads to a need to understand its speciation in aqueous systems and the reactions of those various species. This paper deals in particular with the precipitation of arsenic from aqueous solution in the form of insoluble inorganic compounds in order to remove arsenic from various hydrometallurgical process streams. The solubility and stability of the precipitates is examined. It has been found that many of the arsenic compounds presently used are more soluble than previously accepted and unstable in disposal sites such as tailings ponds.

Jan 1, 1987

By S. G. McAnally

This is one of a series of papers describing mining and crushing methods and costs at cement plant quarries throughout the United States and deals directly with the methods employed and costs obtained at the Reliance quarry of the Giant Portland Cement Co. at Egypt, Pa., although it is more or less descriptive of the methods used throughout the Lehigh Valley cement district. Systems of transportation vary according to local conditions, such as proximity to the mill, depth of quarry floor with relation to the mill level, etc. Methods of prospecting differ mainly in the type f drills used. Systems of storage, crushing, and grinding vary chiefly in the types of units. ACKNOWLEDGMENTS Most of the information regarding the early history of the Lehigh cement district was obtained from the History f the Portland Cement Industry of the United States, by Robert W. Lesley, the first president of the Portland Cement Association. The writer is indebted also to Charles Clader, Giant Portland Cement Co. quarry superintendent, for valuable information regarding present and past methods and equipment.

Jan 1, 1931

By C Bartle

In many operations the use of less electrochemically reactive grinding media in the first grinding stage (for example, rod milling and high aspect ratio SAG milling) is rarely considered. Therefore, in reality a plant may inadvertently be using a 'mixed' media charge. That is, whilst employing inert grinding media during secondary grinding, electrochemically active forged steel grinding media may be used in the primary grinding stage. This paper discusses the impact of such a circuit on the pulp chemistry and flotation response of a refractory gold ore. The Wiluna concentrator has two grinding circuits operating in parallel. Line 1 operates a single ball mill in closed circuit with cyclones, and utilises high chrome grinding media, while the second circuit (Line 2) consists of a rod mill (with forged steel rods) in series with a ball mill, which also utilises high chrome grinding media. The cyclone overflows from both circuits are combined to feed a sulfide flotation circuit. Pulp chemistry surveys were completed around both grinding circuits, and laboratory flotation tests were conducted on the cyclone overflows. The results demonstrate clearly that the rod mill/ball mill circuit operated at significantly lower Eh and dissolved oxygen values, while the percentage EDTA extractable iron was considerably higher, when compared to the single stage ball milling circuit. These variations in pulp chemistry had a marked negative impact on the laboratory rougher flotation response, and suggests that plant performance may be affected.

Jan 1, 2008

By B. McFadzean, S. Pikinini, C. T. O’ Connor

Sperrylite (PtAs₂) comprises about 21% of the platinum group minerals (PGMs) in the Platreef ore and regularly reports to the tailings due to its poor floatability. Hence, improving its recovery will be of great economic value to the South African PGM industry. The reasons for its poor floatability are not yet clear. This paper seeks to understand the interactions occurring between PtAs₂ and common thiol collectors, viz. potassium normal butyl xanthate (PNBX), sodium normal dibutyl dithiophosphate (SNBDTP) and sodium normal mono butyl dithiocarbamate (SNBDTC). By understanding its interactions with these collectors, it is hypothesised that it will be possible to suggest ligands that may help improve the floatability of sperrylite. Mineral-collector interactions were studied by determining the molar energy of interaction using isothermal titration calorimetry and electrochemical techniques. The hydrophobicity of the mineral before and after adsorption of the collectors was determined by heat of immersion and its flotation response determined by microflotation tests. Microflotation tests using synthetic sperrylite at pH 9 showed low collectorless recovery of 34.8% and after adding the equivalent of one pseudo-monolayer of the PNBX collector, the recovery of 32.5% was obtained. Moreover, the addition of up to three pseudo-monolayers coverage of PNBX did not result in any increase in flotation recovery. A small recovery improvement was noted when synthetic plant water with the ionic strength of 0.0484 mol/L was used, but this did not hold for all collectors, with SNBDTP exhibiting higher recoveries in distilled water. Keywords: Sperrylite; flotation; recovery; adsorption energy; collectors; 2SPW (synthetic plant water)

Jan 1, 2020

By James R. Jones

The concern for air pollution goes back centuries as will be seen from this quotation : "Strife and coal, it seems, have a hand-in-hand historical relationship. It was thought by some . . . in the Middle Ages that burning coal filled the air with dangerous poisons. So great was the concern that in 1306 King Edward I of England passed the first and unquestionably the harshest air pollution legislation edict that history will record. His proclamation declared the use of coal an act punishable by death." As related to coal mining, the air pollution problem is primarily that of its customer when using the fuel. Thus the major impact relates to markets for coal rather than the actual mining operation itself. In the vicinity of the coal mine the problem is principally related to fugitive dust from roads, transfer facilities, loading facilities, crushers, etc., and particulate matter (dust or fly ash) from thermal dryers and air cleaning tables. FUGITIVE DUST Most state air pollution regulatory agencies now have rules and regulations requiring control of fugitive dust. Fugitive dust has been defined by the courts as particulate matter other than that emanating from a specific point such as a stack or chimney. A typical air pollution control agency regulation reads as follows : “Fugitive Dust " "No person shall cause, suffer, allow, or permit any material to be handled, transported, or stored; or a building, its appurtenances, or a road to be used, constructed, altered, repaired or demolished without taking reasonable precautions to prevent particulate matter from be- coming airborne. Such reasonable precautions shall include, where applicable, but not be limited to the following:

Jan 1, 1981

By Raymond Wilson

GRINDING costs are an important item in cement manufacture, and the cost of power is one of the large items in grinding costs. Even where power is of secondary importance, cost items dependent on mill capacity are influenced by the efficiency with which the mill uses power. Tube mills typify the grinding mills most generally used in cement plants, though other types are in use. Tube mills have been widely criticized as being extremely inefficient, and this feeling regarding them has led to many attempts to design more efficient grinding equipment. Other types may be an improvement over tube mills, but the improvement has certainly not been revolutionary, at least as applied to clinker grinding. The very fact that there is doubt regarding the relative efficacy of various types of mills is an indication that an adequate basis for an analysis of performance is lacking. The development of methods of analyzing mill performance has been hampered by the lack of a suitable method for measuring the work actually done in pulverizing. There has been no acceptable standard to which mill performance might be compared. As a consequence, it was not known whether the margin of possible improvement in pulverizing operations was large or small. Even direct comparison of different types of mills was seldom possible because most plants had only one type of mill for each type of service. Comparisons between plants were difficult because of differences in the grinding characteristics of various clinkers. Some recent developments complete a chain of circumstances that place the cement industry in a particularly fortunate position for the study of its clinker-pulverizing operations. Modern investigators of grinding phenomena have generally agreed that the best measure of mill performance is the production of new surface. For most materials this measure of performance is largely theoretical and has a rather remote connection with the practical aims of the grinding operation. In clinker grinding, on the other hand, surface area is intimately connected with the properties conferred on the cement by grinding. Moreover, the determination of surface area is rapidly coming into routine use as at test

Jan 1, 1937

By J. Cheung, H. Rabia

The traditional methods for predicting mine air temperatures are based on steady state heat transfer models as developed by Voss (1969) and Starfield (1983). These models are useful in providing approximate predictions of air temperatures in trunk and gate roadways. More complex models are required to provide predictions along faces. In practice, the heat flow in underground mines is of transient nature and recent observations in some British Coal mines show temperature variations of up to 5°C during a working week at any one point. In addition, the recent introduction of district recirculation of mine air in British mines requires a more precise prediction of air temperatures during start up of the system or during breakdown. A transient heat transfer theory based on the work of Jordon is presented. The method lends itself easily to computers due to the large number of calculations involved. The proposed transient model is validated using actual temperature data collected in roadways in Wearmouth Colliery in the North East of England. The transient results are compared with the steady state predictions of Voss (1969). Finally, predictions of air temperature in roadways for a recirculation system will be made using both the transient and steady state models. Temperature predictions along faces will be made using a separate model.

Jan 1, 1989

By G. M. Kintz

In safety work a study of past accidents is of value in determining means of reducing future accidents of the same character. This is particularly true with reference to coal-mine explosions. Data from publications of the United States Bureau of Mines and from published reports of the State inspector of coal mines of Colorado are presented in this circular in the belief that they will be of value to operators by indicating methods of preventing future coal-mine explosions. The tables included are complete only with regard to major disasters. The Bureau of Mines considers as a major disaster one in which five 'or more men are killed. However, this circular also includes a considerable number of minor disasters, Various explosions in the coal mines of Colorado from 1883 to 1932, inclusive, are listed with information available as to their probable cause, number of men killed and measures which, if they had been in use at that time, might have prevented them. John McNeil, first Colorado State coal-mine inspector, on page 43 of his first report for the period ended July 31, 1884, made the following recommendations for the prevention of explosions in the coal industry: True causes could be traced either to insufficient ventilation, carelessness and lack of rigid discipline in carrying on energetic ventilation and other precautions needed to be enforced in a mine giving off explosive gases. *** When any quantity of fine coal dust is observed in an entry, air course, or room it should be made damp and be removed from the mine, and thus beep every place as free from dust as possible. *** A system of bratticing close up to the face of each and every place in the mine from crosscut last made (whether gas should just then show its presence or not) which should not be more than 50 or 75 feet according to the nature of the mine.

Jan 1, 1933

By L. C. Brichta

The Canyon Diggings zinc-lead deposit is in an area of structural deformation of sedimentary rooks in Newton County, Mo., 14 miles southeast of Joplin, within the southern limits of the Tri-State district. Mining and milling on the several tracts covering the area had been carried on sporadically since 1900, and incomplete records show a production of 1,341 tonsof zinc and lead concentrates. On the northern part of the deposit the predominant metal is which occurs as galena, cerrusite, and pyromorphite in broken chert near the surface. On the southern part, lead is subordinate to zinc, which occurs mainly as carbonate and silicate minerals in brecciated chert to a maximum depth of about 150 feet. Analyses of samples from Bureau of Mines drilling indicate that approximately 77 percent of the zinc and 50 percent of trio lead i8 in nonsulfide minerals resulting from the oxidation of sphalerite and galena. Between August 12, 1948, and October 5, 1949, the Bureau of Mines investigated the deposit by churn drilling and sampling 85 holes aggregating 10,571 feet of bore and sampling two mill-tailings dumps and three mine dumps. Factual data on the investigation and the logs of Bureau of Mines drill holes are presented in this report.

Jan 1, 1950

By S. Street

The Environment process, invented by Prof. H.K.Womer and developed at the University of Wollongong, simultaneously treats ferruginous and organic wastes via bath smelting. Conceived in the late 1980's, the patented process was originally developed using steelworks dust to settle solids from sewage, producing a composite material suitable for smelt reduction. Work began on the process in 1990 with the Australian patent having a priority date of February 1990. Early research focussed on settling of solids from sewage, while pyrometallurgical investigations examined smelting in small induction furnaces. By 1992 smelting trials had been undertaken in pneumatic and electric arc furnaces, the process being successfully demonstrated up to on 8 tonne scale. The success of this particular trial, and other smaller trials, resulted in construction of a 100kg DC arc furnace which was commissioned in 1993. By 1994 the main project focus was on development of the smelting technology. Over 3 years of trials on the DC arc furnace have identified and clarified many of the pyrometallurgical reactions. optimum operating parameters, as well as demonstrating the versatility of the process for treating a wide range of wastes. Currently the Illawarra Technology Corporation (lTC), the commercial arm of the University of Wollongong, is pursuing commercialisation of the process.

Jan 1, 1996

By H. O. Poppleton, F. E. Block

This investigation was made to develop a method of preparing high - purity thorium metal in quantities up to 20 kilograms per batch . Several methods for the preparation , purification , and reduction of thorium tetrachloride are discussed . Thorium tetrachloride was prepared by chlorination of decomposed thorium nitrate or oxalate with carbon tetrachloride or phosgene . tion of the crude tetrachloride was achieved by multiple distillations or by filtration of the molten chloride . It was found that high - purity thorium metal could be prepared by sodium reduction of thorium tetrachloride if chloride of sufficient purity were available . Byproduct salts and excess reductant were removed by vacuum distillation , and the resultant thorium metal sponge was consolidated by consumable - electrode or fixed - electrode arc melting . It was demonstrated that metal prepared by this method could be fabricated into bar , rod , or sheet , at room temperature .

Jan 1, 1964

By C. J. Pritchard, R. D. Jacksha, K. V. Raj, C. B. Sunderman

In underground metal/nonmetal mines, repeated localized short-term exposure to high levels of airborne contaminants can become a serious health issue. Currently, there are no common mechanisms to control or mitigate these short-term high exposures to contaminants. To improve miners’ health and safety, the U.S. National Institute for Occupational Safety and Health’s Spokane Mining Research Division (SMRD) is developing a smart monitoring and control (SMAC) system for the real-time monitoring of mine air quality, with integrated countermeasures to reduce high concentrations of airborne contaminants in localized sections of mines. To develop and test a SMAC system capable of being implemented in an underground mine, SMRD researchers built a test apparatus incorporating a fan, louver, ducting and sensors combined with atmospheric monitoring and control software. This system will institute effective countermeasures to reduce contaminant levels, improving miner safety and health.

Jan 1, 2018

In February 1995, Falconbridge Limited approved the construction of a nickel mining and milling facility on its Raglan property situated in the Nunavik region of northern Quebec, Canada. The construction period successfully terminated with the commissioning and start-up of the plant and concentrator in early-December 1997. The estimated life of the project is 20 years with an annual mining rate of 800 000 tonnes of ore, producing 21 000 tonnes of nickel per year. This paper discusses the subject of æRemote Mining in the Canadian ArcticÆ as it applies to the Raglan mine process and people. During the feasibility stage of the project, many assumptions were made which influenced the design and operating parameters of the facilities and the equipment. Transportation, communication, remote logistics techniques and standard industry practices required to support a æfly-in/fly-outÆ operation were reviewed and either adopted or rejected for use at Raglan. These assumptions were æmade to fitÆ the uniqueness of our planned operation. It was also acknowledged that many of them would ultimately impact on the people required to staff the operation following construction. Therefore, their suitability and applicability were examined from an economic, operational and human perspective. In a continuing effort to improve the quality of life for Raglan employees, as well as the economics of our mine operations, these assumptions are under constant review and scrutiny. There is no doubt that experiences gained, and willingly shared by other North American arctic mining operations, proved invaluable and are a big reason for RaglanÆs overall success thus far. The mining industry is being challenged technically to develop lower grade orebodies at the lowest possible cost. In addition to environmental constraints, serious social, political and moral questions are being asked and added to this list of challenges. Miners throughout the world must improve their operating standards and public image if we want to attract the best possible employees. Remote mining operations provide a unique opportunity to experiment with various human resource concepts as well as demonstrate the industryÆs commitment to environmental and community concerns.

Jan 1, 1998

By Rodrigo Toro, Mario Delisle, Claudio Zamora

"The mining market is researching innovative methods to train the workforce for mining which is normally extremely difficult to get. Thus, the dynamic simulation-based technologies become an essential pillar to educate and train the inexperienced staff at the pace required by this industry. Even if Operator Training Simulator (OTS) systems are commonly used in most of industries, knowledge transmitted to operators are unfortunately not ""capitalized"" in general. The OTS systems are usually delivered as a single hardware and software platform and very little as a full service long-term.In this article, an integrated solution to increase the efficiency of the operators is proposed. This solution is based on the combination of dynamic simulation, processes knowledge, virtual reality and the knowledge capitalization through the creation of simulation scenarios and e-learning. The Codelco Ministro Hales plant simulation project for a copper concentrator plant is presented as a real life example.IntroductionDynamic and real-time process simulation have proven to be a must in the development of greenfield projects, providing mechanisms to design and test controls design, interlocks, start-up, shut down sequences and operator training, among others (see (McMillan, 2006) for further details). Early adopters of this technology were utility power plants; in the petrochemical industry have become a standard, and in the mining industry the use of dynamic simulations is growing, especially in new projects and training of operations personnel for the adoption of best practices and new technologies, see (Nikkhah & Anderson, 2001) and (Toro, Ortiz, & Yutronic, 2012).This paper outlines a solution that utilizes dynamic simulations as the base of an integrated platform for operational effectiveness, which takes into account the current scenario of new mining projects and operations, where high turn over rates and needs of specialized workforce have given a special value to this kind of technologies."

Jan 1, 2015

By David Kress

Mill crushing drive systems are essential to cement producers. With the increased emphasis on operating efficiency, it is vital that these systems be dependable and reliable. No one needs the costs or headaches associated with unscheduled downtime or inefficient machinery operation. A reliable drive system starts with the proper selection of the ring, or girth, gear and continues through proper maintenance. Ideally, selecting the right girth gear brings together the gear manufacturer, the system designer and the end user. The gear manufacturer must know the details of the application, the demands that will be placed on the gear and the nature of the equipment to be driven. Similarly, the user and the system designer must be familiar with the variables that affect gear drive performance and service. For example, an application that places a torque load on the drive in excess of its rated capacity will result in gear tooth distress and, in severe cases, breakage.

Jan 1, 2000

By J. W. Jensen

Alloys of manganese and copper containing from 65 to 80 percent manganese possess mechanical strength and vibration-damping capacity in an unusually high degree. The success of their use in reducing vibration in structures depends, to some extent, on their fatigue properties. This report describes the results of fatigue tests on alloys of four compositions. Three metallurgical conditions were investigated for each alloy. Or the basis of the data in this report, the general rule that vibration-damping manganese-copper alloys are comparable to mild steel in hardness and strength may be extended to include fatigue strength. Methods for casting and fabricating these alloys were described in a previous report,4 which contained data on the mechanical and damping properties of the solid-solution alloys, and on alloys aged for 2 hours at 450° C. The aging heat treatment of solution-treated alloys results in optimum mechanical and damping properties throughout the range of specified composition. However, in the present work, measurements also were made on alloys aged for 2 hours at 500° C., because it was theorized that the additional precipitation of a-manganese under these conditions might have a pronounced effect on the fatigue strength of the alloy.

Jan 1, 1961

By R. H. Eric, P. Taskinen, A. Bhalla, P. Halli

Sustainable development requires less energy consumption with lower carbon footprint. In this review the solid state reduction behaviour of three oxide ores using methane gas are briefly summarized based on experimental work conducted in our laboratories. The discussion concentrates mainly on mechanisms of the reduction studied through SEM-EDAX and X-ray diffraction techniques. Limited preliminary kinetic input is also mentioned. Iron ore containing titanium and vanadium could be reduced significantly in the solid state with methane-hydrogen mixture up to 400 °C lower than is needed in ordinary solid state carbothermic process. The reduction of chromite and manganese ores were possible similarly at lower temperatures with potential energy savings lower carbon footprint.

Mar 1, 2017

By C. E. Munroe

In order to meet the emergencies of the world wr, tne quantities of explosivea produced in the Unitecl States, and the number of explosives plants were onti:.1.1.:l,lly ncreased so that when the armistice was declared the Government had on hand larg ..mounts oi militazy explosives in excess of existing military needs. Tle stor3.gs of these explosives entailed a liirge expense and their protection neessitatei the employment of m'3.l'lY men who could be better employed otherwise in the military estlish.11ent. Moreover, mar.y ex.ploives, like QJ.l other material, deteriorate on prolonged storage, They lose tht precise definiteness of properties and behavior on which reliance· is placed in military operations, The continued expen3e and d3.nger ttending storage of theae explosives might be diminished by dcst1et1on of the surplus beyond immediate needs, but such·deetniction is danger• ou5 qnd coetly. Hence, the evident solution o! the problem was the salvage d prompt ut111zation of the ru.rplua •

Aug 1, 1922

By Kenneth N. Weaver

Introduction and Historical Background State Geological Surveys have been deeply involved in industrial minerals from their inception beginning in the first half of the 19th Century. To Massachusetts belongs the credit of having carried out the first Geological survey under state auspices on the Western Hemisphere. One of the causes leading up to this survey was. Governor Lincoln's message to the legislature of May 29, 1830, from which I quote in part: "Much knowledge of the natural history of the country would thus be gained (from a geological survey), and especially the presence of valuable ores, with the localities and extent of quarries and of coal and lime formations, objects of inquiry so essential to internal improvements and the advancement of domestic prosperity, would be discovered.". Similar phraseology is present in practically all of the initial organic acts creating the first State Surveys. High on the list of priorities for these embryo surveys was an inventory of the mineral resources of the State with particular emphasis on the industrial minerals. Prom these early beginnings, the state surveys have developed a great wealth of geological data either directly or indirectly relating to the development of mineral resources. One can gain some conception of the effort that state surveys today place on industrial minerals studies by noting the projects in which they are engaged as reported in the State Geologists Journal. In 1970, for example, approximately

Jan 1, 1972

By K. C. Corin, M. S. Manono

The mining and mineral concentration of Cu-Ni-PGM sulfide ores in South Africa occurs in semiarid regions. The scarcity and availability of water resources in these regions has become one of the biggest challenges facing mineral concentrators.S Owing to this challenge, concentrators have to find ways through which they can manage and control their water usage. Recycling and re-use of process water in mineral concentrators has therefore become common practice. This practice is beneficial in that it reduces reliance on municipal water, harnesses compliance to stringent environmental regulations on water usage, and it also offers a better response to the Sustainable Development Goals. This could however be somewhat concerning to the operator as recirculated water often has higher concentrations of ions compared to fresh or potable water. The unintended change in the process water quality may potentially affect critical aspects of flotation such as the stability of the froth. This has led to the need to find those process water ions that have the greatest impact on froth stability. Thus, this paper investigates the effect of various ions common in process water of a typical Cu-Ni-PGM concentrator on froth stability. Bubble size, water recoveries, foam height, and dynamic froth stability in both twophase and three-phase flotation systems are used as proxies for froth stability. Findings of this study are deemed crucial towards the development of a process water management protocol in sulfidic Cu-Ni- PGM ore concentrators. Keywords: Bubble diameter, electrolytes, flotation, froth stability, water quality

Jan 1, 2020