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By S. M. Shelton, W. A. Calhoun, M. M. Fine, T. L. Johnston

"FOREWORDFerrograde manganese ore or its equivalent is essential to the manufacture of every ton of steel produced; although it is well known that there are large deposits of low-grade are in the United States, the production of substantial amounts of ferrograde material from domestic sources presents a problem that becomes more and more critical as the stockpiled ore depleted through inability to procure adequate supplies from foreign sources. Consequently, a program of laboratory,and pilot-plant investigation designed to solve the problem of obtaining a domestic supply of manganese has been undertaken by the Metallurgical Division, Bureau of Mines.This paper is one of a new series that include reports of results obtained in the various investigations conducted under the manganese program. The scope of the program and the organization that was set up to direct and supervise the were discussed in the foreword of the first paper of this series, Report of Investigations 3606 Manganese Investigations. 1. Concentration of Manganese Ores,from the Drum Mountain District, Utah, by S. R. J. D. Vincent, and C. R. Schack. Other reports will be published as the work progresses."

Mar 1, 1942

By Wesley A. Grosh

The Cuyuna range in central Minnesota has been the source of substantial tonnages of, manganiferous iron ores for almost four decades. To Increase the Nation's self-sufficiency in manganese reserves, the Bureau of Mines initiated a comprehensive investigative program to determine and develop the potential manganese reserves in the region. In the course of compiling all available information on the Cuyuna range, the Scallop-Todd lease appeared to be an area having favorable possibilities for developing substantial reserves of manganese. Early drilling on this lease indicated considerable tonnages of material relatively high in manganese. More recent drilling substantiated the size of the deposit but Indicated lower manganese values. However, beneficiation tests of samples obtained from the recent drilling indicated that the material was amenable to concentration.

Jan 1, 1953

By J. P. Nielsen

When two grains in a polycrystalline specimen meet at a point in the course of grain-boundary movements, and the new boundary created at the point is one of relatively low specific free energy, a nonequilibrium boundary condition occurs. The nonequilibrium is enhanced if the other grain boundaries involved at the point of meeting are relatively high in specific free energy. The nonequilibrium results in a correction by growth of the complex grain (two subgrains) to a large size, sufficient in many cases for it to become a self-propagating unit, i.e., a recrystallization grain. This mechanism, herein called "geometrical coalescence," is proposed as a logical origin for recrystallization nuclei, particularly for secondary recrystallization. RECENT publications1-' indicate that considerable progress has been made toward a complete understanding of the three microstructural processes in metals: recovery, recrystallization, and grain growth. However, a major problem persists, namely, the origin of recrystallization nuclei. It is generally accepted that once a recrystallization nucleus, a secondary recrystallization nucleus particularly, has reached a certain size, it will continue to grow at the expense of its neighbors, simply as a consequence of grain-boundary free-energy considerations. What has remained obscure, however, is the mechanism whereby such a nucleus comes into being and grows to the self-propagating size. Recrystallization Nucleation in a Two-Dimensional Grain-Boundary System In the left portion of Fig. 1 is shown schematically the meeting of grains 1 and 4 on disappearance of boundary 2-3, i.e., the boundary that existed between grains 2 and 3, as might happen in the course of normal grain-boundary migration. If, by chance —and the probability is not necessarily small— grains 1 and 4 are close together in their mutual orientations, or in some other special way mutually oriented so that the new common boundary has relatively a very low specific free energy (hereinafter referred to by s), then the grain boundary arrangement as depicted in the figure is highly unstable. This is particularly so if boundaries 1-3, 3-4, 4-2, and 2-1 are high in their s values. Assuming, for the sake of argument, that boundary 1-4 has a s equal to zero, and the s's of all the other boundaries present are equal to each other and constant, then the boundary arrangement on the right in Fig. 1 will be

Jan 1, 1955

By W. E. L. Minter

The most important Witwatersrand gold placers occur on extensive unconformity paleosulfaces that were produced during protracted periods of fluvial degradation. The erosional etches on what was generally unlithified sub-strate indicate that low sinuosity erosion patterns prevailed. The transport systems were dominantly braided fluvial with a minor debris-flow component. The placer sediments were non-cohesive sands and gravels. They were evidently transported by fluctuating, yet perennial, discharges across extensive, low relief braid plains, not far from littoral environments. Progress made in understanding heavy mineral transport processes now emphasizes the importance that selective entrainment probably had in producing concentrations. Cognizance that these characteristics are not unique to the Witwatersrand should be taken into account when designing exploration models.

Jan 1, 1991

By Yagmur Sirinyurt, Ayhan Ali Sirkeci, Gülay Bulut, Mustafa Özer, Tuncer Acar

"The basic requirement of glass industry for the silica sand is at least 99% SiO2 content. On the other hand, coloring impurities such as Fe and Ti, must be removed. Flotation is the most widely used method for the purification of silica sands from impurities. In this study experimental studies were carried out to reduce Fe content of Mersin (Turkey) district silica sands by flotation. Silica sand sample with a d80 particle size of 1.85 mm was reduced below 0.5 mm in size. Then the size fraction -0.5 +0.106 mm was subjected to flotation tests. In flotation tests, sulfonate-type R801-R825, fatty acid based DER NA 7 (Produced by a Turkish company) and HA110-HA150 a blend of various chemicals produced by Mersin Cam-Is Mining Company (producer of glass raw materials) were used as collectors. Flotation tests showed that sulfonate type R801-R825 collectors provided much better results in acidic medium (pH: 3). The optimum pH value for DER NA, HA150 and HA110 collectors was found to be 7. It was observed that the addition of collector at once caused an increase in the amount of floated product that resulted in a loss of silica to the tailings. In the case of multistage addition of the collector much better selectivity was achieved. As a result of flotation tests conducted under best conditions, a concentrate assaying 0.046% Fe was obtained with a weight percentage of 93.4 when DER NA 7 was used as a collector. In the case of R801-R825 a concentrate was produced with 0.058% Fe content with a yield of 98.4%. On the use of HA150-HA110 the concentrate was produced with 96% weight recovery and 0.052% Fe content."

Jan 1, 2014

By A. Brown

IN INTRODUCING the subject of rock pressures, it may safely be assumed that mining men are only too familiar with the physical effects of strata stresses that accompany the extraction of minerals. It may be further assumed that they have, as individuals, arrived at certain conclusions regarding their nature, based upon years spent in observing such phenomena and in learning how to continue mining in spite of them. Such hardly won experience forms the core of what is often referred to as 'pit sense'. This essential type of knowledge is not ?based on theoretical considerations, nor can it be found in text books. It is highly individualistic in nature and almost impossible to pass on from one generation to another in terms of precise rules for guidance. It is this aspect of individual judgment based on practical experience that has led to the significant phrase The Art of Mining.

Jan 1, 1956

By William A. Fuchs

A study of carbonaceous ore at the Santa Fe mine (Corona Gold Inc.) shows that there is no quantitative relationship between organic carbon content and preg rob, although much of this material preg robs. However, there is a relation between K20 and preg rob. Preg rob generally occurs only in those samples with greater than 2% K20. X-ray diffraction and chemical . studies show that the critical factor is the illite content of mixed (possibly interstratified) illite-smectite. Apparently illite, at a certain threshold, "geo-activates" the carbon. The potential for easily monitoring preg rob using a gamma ray spectrometer is discussed.

Jan 1, 1990

By Ralph H. Knode, Stephen P. Collings

INTRODUCTION The Crow Butte uranium deposit is located in northwest Nebraska near the town of Crawford (Figure 1). The deposit was discovered during the fall of 1980 by Wyoming Fuel Company, operator of the Crow Butte Joint Venture. The Crow Butte Joint Venture is owned 50 percent by Wyoming Fuel Company, a subsidiary of KN Energy, Inc.; formerly Kansas-Nebraska Natural Gas Company, Inc., 40 percent by Ferret Exploration Company, Inc., and 10 percent by First Exploration Company. A preliminary announcement made in January 1981 indicated a "probable potential" reserve in excess of 25,000, 000 pounds U303. Drilling during 1981 and 1982 confirmed these reserves and indicated the presence of more than 30,000,000 pounds U308 having an average grade in excess of 0.25 percent U308. Wyoming Fuel Company was initially attracted to the area in 1978 by favorable regional geology for sandstone uranium deposits and weak radioactivity noted in regional oil and gas holes. Exploration drilling began in 1979 following the formation of the Crow 3utte Joint Venture. Drilling has continued up to the present, at which time the Joint Venture is ready to proceed with a pilot scale solution mine. Environmental baseline data have been acquired and the permit applications for the pilot scale mine have been submitted to the Nuclear Regulatory Commission and to the applicable state agencies in Nebraska.

Jan 1, 1984

By Brian Fulcher

The Fort Lawton Parallel Tunnel was built in 1990 - 1991 by Morrison Knudsen Corporation (MK) as an integral part of Seattle METRO's planned expansion of the Westpoint Treatment Plant. The project included a concrete lined 2542 m (8,340 ft) long tunnel bored in sands and clays under the presence of methane gas and over 27.4 m (90 ft) of ground water table. The tunnel roughly paral¬lels an existing and still operating 3.65 m (12 ft) diameter tunnel originally completed in 1909. The parallel tunnel was constructed using a Lovat 4.72 m (15 ft-6 in) earth pressure balanced TBM with ribs and timber lagging as primary support. The tunnel alignment crossed under as much as 91.4 m (300 ft) of overburden as well as twin mainline railway tracks; terminating in a shaft adja¬cent to the Seattle ship canal. The project was completed in June, 1991 after a final "wet-tap" tie-in to the existing brick-lined sewer; over five months ahead of the contract schedule. This paper will describe the construction methods, job site conditions and difficulties encoun¬tered on this very challenging and successful project.

Jan 1, 1993

By Jorj O. Osterberg

This paper is for presentation at the 14th Annual Members Conference of the Deep Foundations Institute held at the Hyatt Regency Hotel, Baltimore Maryland on October 10, 1989. This is an introductory presentation of a one hour symposium on the applications of a new testing device. This paper discusses how the device works and its uses. Papers following this describe: - How the cell is constructed and calibrated - Two projects on which the device was used on long driven piles to determine the frictional capacity - A bridge project on which the device was used on an instrumented test drilled shaft and a working drilled shaft

Jan 1, 1989

By R. W. Stahl

Gas accumulation and dust suspension are the major safety hazards in coal stockpiling and reclaiming operations. This report presents a schedule of safety precautions and plant design features devised by the Bureau of Mines to reduce danger from these and other sources.

Jan 1, 1965

By E. Roman E.

A novel anode slime purification process was developed and tested at pilot scale in the Chuquicamata Refinery. The process consists of three main stages: First, an atmospheric alkaline leaching at 90°C, under controlled pH and ORP operation parameters where metalloid impurities are preferentially removed from the anode slimes with high efficiency. In a second stage, alkaline washing of the mud leached with addition of reducing agent, with the intention of reducing the silver of the AgCl to metallic silver releasing the chloride, and finally, copper and other remaining impurities are leached out in mild conditions (60°C, one hour in sulphuric acid). In a side process Se, Te, and Sb are recovery with high efficiency from the alkaline liquor as chemical grade products. The global balance shows a high mass loss yielding a final product with high precious metal and low impurities content showing advantages in both a technical and economic point of view with a clear environmental sustainability. This treatment allows either the direct sale of the purified anode slimes or its pyrometallurgical treatment to obtain metal doré without emissions of Se, Sb and As. Chemical mechanisms for this novel process are also described.

Jan 1, 2007

By Michael Arnold, Robert Bachus, Michael Bracher, Jamey Rosen, Robert Roff

"For a high hazard USACE facility, the Center Hill Dam in Tennessee, several disparate streams of data were compiled into a single geospatial and relational enterprise data management system to store, analyze, visualize and distribute the data collected during installation of a deep cutoff wall. These data streams included historical drawings and pre-construction plans and grouting records; geological data from boreholes; attributes of barrier wall elements; element verticality data analyzed from multiple measurement methods; and concrete field and laboratory analytical data. A previously developed data management system developed by the authors, WallTracker, was extensively modified to also include manually collected and real-time measurements from several types of dam monitoring instruments. The system now uses enterprise database technologies with Geographical Information Systems capabilities to manage and relate these data streams into a common platform and allows access to the raw and interpreted data via web and desktop-based interactive tools, including interactive map and cross-sectional viewers and other graphical and tabular reporting tools. One of the primary benefits of this system is the neartransparent interaction that is possible with the Nashville District of USACE on the project. These techniques can now be effectively incorporated into systems that address the unique construction and data management tracking requirements for dams, dikes, and levees.IntroductionThe Center Hill Dam rehabilitation, as with other deep foundation installations, requires the contractor to collect a substantial amount of information over the course of the project, both for internal quality control of construction progress and methods, and for demonstrating compliance with owner specifications. This paper discusses techniques used at Center Hill Dam for consolidating, visualizing and analyzing construction and instrumentation data using relational database and Geographic Information Systems (GIS) technology, collectively referred to as an Information Management System (IMS).The remainder of this paper presents the needs and objectives of the IMS, the components and data flows involved, the capabilities and user interfaces of the systems, and the benefits for the end users."

Jan 1, 2017

As an Inspector of Mines in Queensland, my main responsibilities include the enforcement of the Mining Act 1968 - 1986, the Mines Regulation Act 1964 - 1983 and the Metalliferous Mining regulations 1985 to promote the safe and responsible exploitation of the States' mineral wealth. An important adjunct to this task is the offering of an advisory service to the mining industry. However, in the pursuit of my duties to this regard, I have sadly observed in some cases, numerous wrong doings and negative activities by miners which have led to their ultimate demise, not to mention that of others. Despite what I consider corrective advice, I have witnessed, again in some cases, disregard and blind pursuit for the wrong end. This then is a novel approach to get the message home in the form of a light hearted cartoon presentation relating the saga of an average Aussie battler entering the mining game unprepared, making the wrong decisions due to his own ignorance and the cleverness of others, leading finally to his and possibly others' downfall. It is not intended to insult any particular profession or group of individuals and only endeavours to impart to readers and listeners, the message of being prepared and alert when entering the gold mining industry. Even though the presentation focuses on the woes of a rookie alluvial gold miner, a similar analogy could be drawn with his hard rock counterpart since the basic issues that I have attempted to address are common. By no means is there a saga complete because there are many more traps a miner can inadvertently fall into and only time has prevented me from referencing them.

Jan 1, 1989

By J. H. Bernard, K. Zak

Abstract- The three traditional types of Variscan vein Pb-Zn-(Ag) mineralization recognized in the Bohemian massif from historic paragenetic studies are confirmed by modern metallogenic studies. Stable C, S, and 0 isotope data, as well as Pb and Sr isotopic ratios of the deposits, indicate a predominantly crustal origin of the constituents in all three types. Although the data also suggest differences in temperature and pressure of formation, and the oxidation conditions and nature of the hydrothermal fluids, nonetheless they are consistent with prevailing metallogenic classifications of the vein mineralization.

Jan 1, 1992

By T. A. Rickard

Slovenliness is as reprehensible in words as in clothes. Much writing that we recognize as poor in style is merely sloppy. Just as some students postpone the necessary shave or forget to change their collars, so young engineers in writing drop their articles, definite and indefinite, or omit prepositions where they are required, possibly to compensate for these they use unnecessarily The work will begin [on] Saturday. The work will begin [on] Saturday. `Influenza seriously affected many mines [during] the last three months. Flotation in America [during] the last two years has made tremendous strides. Construction of the mill started [on] August 12, 1915, at which time 75% of the excavation was completed. The idea I wish to convey is [that] there are mineral deposits to which the present law applies badly. For this reason, if there was [for] no other, the ownership of the ore below and [of] the surface above should go together. When a unit of mapping is furnished, be the unit a claim or [a] group of claims, it is necessary .. . A fully stocked store was started in Park City and all employees [were] sold merchandise on a strictly cost basis. The word "merchandise" is left without government or agreement. I suggest: ". . . and merchandise] was sold to all the employees on a strictly cash basis.". The verb `be' is serving concurrently both as a principal and as an auxiliary in the following: At first the work was interesting and [was] liked by most of the men. The sulphide ore was more complex or [was] milled at an increased cost. The failure to repeat tie auxiliary verb in successive clauses is a common error, as in The filter is filled with liquid allowed to empty, and then ignited.

Jan 1, 1931

By G T. Jemwa, F Rousseau, F J. Wolfaardt, J A. M Rademan, P W. Smit

Mining companies are increasingly faced with the challenge of reducing operating costs while maximising throughput and profitability. At the same time, the grade and quality of treated ores are becoming poorer and more variable, resulting in suboptimal process performance.It is now widely accepted that strategies to drive operational goals must revolve around improving plant availability, reliability and process efficiency. In particular, progress in plant automation and control systems has seen a trend towards unified frameworks for control and optimisation of mineral processing plants. These frameworks seek to seamlessly integrate different roles and tasks involved in process operations - IT, automation, plant maintenance and operations. An integrated solution framework for reducing process variability, increasing process efficiencies and maximising plant availability and reliability is discussed within the context of a typical milling circuit. The framework exploits a real-time analysis ægapÆ evident in production operations that prevents timeous identification of equipment and process failures. This is achieved by leveraging predictive analytics for equipment health monitoring, control loop monitoring and advanced regulatory control solutions towards enhanced process performance, improved asset management and regulatory compliance. The framework provides for early and actionable warnings on equipment and process degradation using real-time operational data.Resolving these problems can potentially avoid unplanned downtimes, process instabilities and other operational surprises, thus ensuring optimal plant throughput and optimal process behaviour for improved recoveries. Integrating control systems and plant automation with advanced analytics to analyse and optimise processes enables operations to achieve reductions in the variability of key process parameters. In addition, early detection of equipment malfunction or suboptimal process conditions leads to improved equipment availability and reliability. Ultimately, these operational gains reflect in profitability because of plant throughput and recovery gains. These benefits are demonstrated using data from a South African gold mining operation, where such an integrated asset and process health monitoring framework for process optimisation has been implemented.CITATION:Jemwa, G T, Wolfaardt, F J, Smit, P W, Rademan, J A M and Rousseau, F, 2013. Towards an integrated framework for asset and process health monitoring and optimisation on a milling circuit, in Proceedings World Gold 2013, pp 137-148 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By Eun Duck Park

The gold catalyst supported on iron oxide was prepared from gold dissolved in aqua regia by a deposition-precipitation method and applied to CO oxidation in the absence and presence of hydrogen. Some characterization methods such as X-ray diffraction (XRD), nitrogen adsorption, transmission electron microscopy (TEM), temperature programmed reduction (TPR), temperature programmed oxidation (TPO), and the pulsed CO chemisorption with temperature programmed desorption (TPD) were conducted to explain different catalytic activities of Au/Fe2O3 catalyst pretreated at different conditions. The particle size of gold was about 10 nm for Au/Fe2O3 calcined in air at 373 and 573 K. For complete CO oxidation, the decreasing CO conversion with a reaction time was observed at low temperatures but its initial catalytic activity can be restored by a heat treatment at high temperatures. This catalyst was quite active for the selective CO oxidation in the presence of hydrogen especially at low temperatures. In the presence of hydrogen, the deactivation was significantly diminished.

Jan 1, 2006

By M. J. Laurila

On-line analyzers have made possible the use of fuzzy logic control (FLC) for local control applications in coal preparation plants. This includes FLC of heavy media vessels, cyclones and froth flotation. These circuits can be controlled in real time in a feedback control loop with an on-line analyzer. Control strategies can be developed using statistical process control (SPC) techniques that are first applied offline in manual mode through the use of control charts. This process is then brought on line using FLC in conjunction with an on-line analyzer to automate the circuit. The advent of programmable logic controllers into preparation plants has enabled the implementation of regulatory control. As shown in Fig. 1, regulatory control is the first level of process control as applied in a processing facility. This involves: ? The logic sequences for start-up and shutdown procedures and all the necessary interlocks for safety purposes. ? The systems to control individual parameters and individual units. Various sensors provide information that is useful to plant operators, while some can be used as signals to simple control loops (Couch, 1996). This is the foundation of process control. It must be performed well if there is to be any success in supervisory control (level 2). Supervisory control involves overseeing and directing the operation of unit operations, or of the whole plant. This includes more complex loops with cascade control. And it may involve feed forward and feedback systems. There have been some applications of this kind of control to thickeners and flotation circuits in coal preparation plants. In addition, there are supervisory controls on some dense medium circuits and, in a few cases, on jigs. These are implemented with proportional integral- derivative (PID) controllers that are available in the PLC or distributed control system (DCS) operating soft ware. In a coal preparation plant, there might exist 200 to 400 PID loops. In a coal-pro¬cessing plant, this number is increased to 2,000 loops or more. It is important to use the correct algorithm or function to control a process variable to the point where automatic control shows a markedly decreased variability over manual mode. This is where fuzzy logic and neural networks have an advantage over traditional model-based expert systems. Because dynamic models of coal preparation unit operations do not exist, model-based expert systems that are prevalent in minerals processing cannot work. Not enough is known about the dynamics of the gravity separation processes employed in coal preparation. Therefore, an artificial intelligence (AI) system consisting of a subset of fuzzy logic, genetic algorithms and neural networks must be applied in coal preparation plants if a supervisory control system is to be successful across a range of feed characteristics and variable set points.

Jan 1, 1997

By S. J. Im

Bupyung Silver Mines daily treats average 14 tons of concentrates containing 9,000 g Ag per ton. Bupyung Silver Refinery uses Merrill Crowe process to recover the silver from the leach solution containing 1.0 g/l Ag; Series of experiments were carried out to recover the silver from the solution by means of direct electrowinning in place of Merrill Crowe process. The recovery of the silver was 99% when the cell voltage and the retention time were 1.9 v and 3.0 hours, respectively. Power consumption was 3.2 Kwh/kg of Ag. It was found that impurity buildup was not significant during the recycling. The direct operating cost for the electrowinning was evaluated to be $ 0.35/kg of Ag.

Jan 1, 1984