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By Larry A. Lass

The U.S. Bureau of Mines, in cooperation with the Iron Range Resources and Rehabilitation Board, investigated the potential of using northeastern Minnesota papermill waste sludges as a binder for Mesabi Range iron ore (taconite) concentrate. Sludges from five different commercial papermill waste treatment operations were evaluated in laboratory tests. Except for the coarsest sludge, all were fairly easy to blend with the taconite concentrate using conventional mixing methods. The coarsest sludge had to be reslurried at 2 pct solids before adding it to the concentrate in order to obtain pellets without visible sludge clumps. Drying and grinding the sludges made them less effective as binders because of a lower degree of rehydration. On a dry weight equivalent basis, twice as much raw sludge binder was required to obtain similar pellet physical properties as with bentonite; however, the pellets made with raw sludge had superior metallurgical properties. Over 30 pct higher reduction rates and over 1500 C higher softening temperatures were obtained with sludge binder than with bentonite. Sludge D, which had the lowest fiber and the highest alkali metal content, resulted in the lowest reducibility enhancement. Even though more raw sludge was required than bentonite, the sludges have virtually no value, and therefore may provide a cost-effective additive binder for producing improved metallurgical-quality pellets. Large-scale testing has not been done to confirm these laboratory results.

Jan 1, 1989

By C. K. C. K. Gupta

The rare earths in elemental form are required for a variety of scientific and technological purposes. They are not easily obtained in this form, due to the great chemical stability of the rare-earth compounds and the strong tendency of elemental metals to react with everything they come in to contact with, especially at high temperatures. Beginning in the 1950s, when sufficient quantities of separated rare earths became available, as the result of intense research and development, three processing routes were developed to accomplish the preparation of all 16 naturally occurring rare-earth elements. They are chemical reduction of the halide intermediates, the oxides and electrochemical reduction of chlorides and oxide-fluoride mixtures. Not all the processes are effective with all the rare earths. In spite of the celebrated similarity of trivalent rare earths, the physical properties of individual rare-earth elements are sufficiently different that a variety of techniques are required for their preparation. The development of reduction processes for the rare-earth metals are covered in this paper, with focus on the oxide reduction routes. The strong reliance of effective reduction processes on the fundamental science of reduction reactions is highlighted.

By Terence M. Gordon, Mati Raudsepp, Gregory M. Dipple

Four methods of measuring mineral abundance in a rock are examined for their potential in assaying for high-tech industrial minerals. One method uses X-ray powder-diffraction data and the other three rely on whole rock chemical data and information on mineral assemblages and mineral compositions. All four methods were employed to estimate wollastonite content in diamond drill core of skarn collected as part of an exploration program and are compared to visual estimates of wollastonite content from core logs. These techniques for assaying wollastonite span a considerable range ofaccuracy and expense, and combined, define a non-linear relationship between these variables. Accuracy increases rapidly relative lo expense up to total costs of about $50 per analysis. Assay methods in the $50-100 per analysis range have associated errors of 5-10% relative and probably suffice for most exploration programs. Improvements in accuracy above this level require a much larger investment. The most expensive assay technique (-$300 per analysis) yields the most accurate measurement of grade (relative error -1%). Its application may best be limited to periodic checks on other assay techniques and for fine-tuning ofmineral separation procedures.

Jan 1, 2001

By R. E. Heithecker

Zwolle oil field of Sabine Parish, La., is different from most oil producing areas of the State in that the oil is obtained from marl and chalk-rock formations. The thickness of the reservoir rocks averages 500 feet; but production is not continuous throughout this thickness, as the oil apparently is localized in vertical and nearly vertical solution cavities and channelways or in porous zones of limited horizontal extent. The nature of the oil accumulation has caused two outstanding peculiarities of the field: (1) About 60 percent of the tests drilled were dry holes and (2) there were many instances of well interference. Commercial production was discovered in November 1928, after 17 years of prospecting in and around the present limits of the area now developed which has a length of about 22 miles and a maximum width of 4 miles. The field had produced 10,266,896 barrels of oil to January 1, 1934. The oil ranges in gravity from 400 to 420 A.P.I. Although the field is divided into several districts which are more or less clearly defined and separated by unproved territory the term Zwolle field", as used in this report, includes the entire area from Blue Lake on the west side, through Zwolle proper, and eastward, including the Many or Eastern extension.

Jan 1, 1934

By Daniel I. Carey

Current and potential dragline reclamation usage was evaluated for the U.S. coalfields based on data gathered and analyzed during field surveys, literature reviews and contacts with manufacturers. It was concluded that current wining plans have been adapted to federal and state strip mine and reclamation laws in ways which limit the potential for drag line reclamation systems at active mine sites. At abandoned conventional contour mine sites in steep-sloping areas such as central Appalachia, however, it was found that dragline reclamation systems have great potential application and may be the only practical solution to many reclamation problems. Alternative dragline systems were examined for restoring abandoned sites, and it was concluded that a tower excavator system offered superior characteristics and should be evaluated and developed under field conditions. A testing program was developed to provide a framework for the monitoring and analysis of cost, production and environmental data during a field demonstration of a tower excavator system.

Jan 1, 1981

By J Hadjigeorgiou

Narrow vein mining, as most types of mining, faces important geotechnical challenges. The specificity of geotechnical challenges in narrow vein mines stems from the nature of the deposits, which are often inclined, discordant and found within fractured rock or faults or in shear zones within country rock. This complicates the construction of representative geomechanical models and limits the applicability of several engineering design tools. Furthermore, in certain cases, the severity of encountered geotechnical problems is considerably greater in narrow vein than in wider orebodies. This paper provides an overview of geotechnical and other challenges in narrow vein mines with a focus on how these are currently addressed. Of particular concern is the use of manual labour working close to the mining face where there is greater exposure to geomechanical hazards. This review concludes with a particular emphasis on understanding the limitations of commonly used engineering tools and techniques to address geotechnical problems in narrow vein mines.CITATION:Hadjigeorgiou, J, 2012. Geotechnical challenges in narrow vein mining, in Proceedings Narrow Vein Mining 2012 , pp 15-22 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 26, 2012

By Chandrakala Kari, S. Mohan Rao, Gajanan Kapure, K. S. Raju

High carbon ferrochrome production process is energy intensive, consumes approximately 3300-3400 kWh per ton of metal produced. This amounts to ~ 34% of the total ferrochrome production cost. The power costs in India are almost 4 times greater than the leading ferrochrome producing countries like South Africa. Hence there is a need to look for alternative sources of energy. In ferrochrome making process large volumes of high concentration CO gas (~ 85%V) is developed at ~400-5000C, which if combusted within furnace represents high potential for significant electrical energy savings. In a typical heat in the state-of-the-art submerged arc furnace, about 34 kmol of CO gas is generated per ton of ferrochrome metal, which, if post combusted to CO2, represents 7620 MJ of energy. Post combustion of the evolving CO (and H2) gas to CO2 can be achieved by providing additional oxygen before the generated CO gas leaves the furnace. In this paper, a concept of post combustion in submerged arc furnace as potential source of significant electrical energy saving in ferro-chrome making process has been explored. The prospects and limitations of the same are discussed. The value of this paper lies in its attempt to explore the post combustion application to submerged arc furnace with an objective of significant reduction in electrical energy consumption in ferrochrome production process.

Jan 1, 2007

By M. Robson

Water & Earth Technologies, Inc. (WET), Habitat Management, Inc. (HMI) and Chevron Mining, Inc. (CMI) together developed a solution for reclaiming steep southwest facing slopes in mining Area 12C that have historically been prone to excessive erosion, low vegetation establishment and continuing maintenance. Area 12C is located in the east wing of the Chevron McKinley Coal Mine, 27 miles northwest of Gallup, New Mexico, on Navajo Nation land administered by the Office of Surface Mining (OSM). Mining in this area was completed in May of 2007. Challenges encountered for this reclamation project included the need to reclaim graded material on a slope of 18-35% with southwest facing aspect, the presence of undisturbed rock outcropping that needed to be avoided during reclamation, the operational need to limit bulldozer pushes and the inability to import or export additional materials for construction. Two different reclamation alternatives were considered for Area 12C. The first alternative would use a traditional reclamation approach including three levels of draining terraces designed to convey water on a 3% slope to a single riprapped down drain. Terracing and down drains have been used to reclaim areas with similar terrain conditions elsewhere at the McKinely Mine and have failed to adequately control erosion (Williamson 2006). Terrace overtopping and down drain blowouts have been issues in maintenance and functionality for the mine. Maintenance routines consist of cleaning out terraces where they have filled in with sediment and repairing damaged or blown out terraces and down drains.

Jan 1, 2010

By Ayman Tawadrous

Cave mining offers a flexible technique to exploit large, low grade, deep ore bodies with low operating costs. It is typically done in either a top down approach; i.e. sublevel caving, or in a bottom up approach; i.e. block or panel caving, to extract ore bodies that may have been previously considered unfeasible to mine. Sublevel Cave (SLC) mining, in particular, is a cave mining method based upon the utilization of gravity of blasted ore while the overlying host rock fractures and caves under induced stresses and gravity. Thereby the caved waste originating from the overlying rock mass fills the temporary void created by ore extraction to achieve a controlled collapse of the roof.

Jan 1, 2015

By R. C. Miranda

Flotation is an operation widely used in mineral processing because of its aptitude to recover minerals of interest very efficiently. Flotation is often responsible for making possible the exploitation of mineral deposits of low concentration. In flotation various processes phenomena occur, some of which have still not been explained scientifically. Due to this fact, there are no models that can be widely applied in flotation control. Thus, in most cases, the control is done by experienced operators who are able to visually classify the types of foam into different categories and each one of them is associated with an operating actuation. In this situation, image analysis is configured as a solution that has already been employed in several ways. In this paper, a control strategy based on the colour of froth on a direct flotation of a nonferrous metal is presented. Moreover, the paper reveals the theoretical basis of the method, the critical points, difficulties and improvements that can be implemented. Data of grade were collected from the mineral of interest and RGB (red, green and blue) data of final concentrate of the froth. The mineral grade was collected and analysed during one month of operation and RGB was obtained using a camera. It was verified that the red colour showed the same trend of the grade curve in the concentrate. Thus, the use of this online data in optimising control was introduced. The laboratory grade is used to calibrate the colour set point. Therefore, it was possible to monitor in real time the trend of enrichment and depletion of a non-ferrous mineral in a flotation. It was possible to establish an online control strategy based on simple data acquisition. The result was an increase of 10% on production.

Sep 1, 2012

By R. Hogg

"Particles play an important role in our environment and in many aspects of human activity. Much of the Earth's surface - sand, soil, rocks - consists of particles, as do clouds in the atmosphere, smoke from fires, and dust in our homes. Many of the foods we eat - cereals, flour, instant coffee - and everyday items such as pharmaceuticals, cosmetics, detergents and other cleaning products are encountered in the form of particles. Inks and paints consist of very fine particles dispersed in liquids. Modem agriculture uses huge quantities of fertilizers and pesticides, largely in particulate form. The list could be extended almost indefinitely; particle systems are obviously an important part of our daily lives. But what do we know about them? For most people, the answer is probably: not much.We are all familiar with the three common states of matter: gas, liquid and solid. In many respects, particle systems should be regarded as a distinct class of their own. The particles themselves may be solid but we all know that a heap of sand is quite different from a solid rock. A cloud of liquid droplets - fog - has much more in common with a cloud of solid particles - smoke - than it does with a bucket of water. There are certain characteristics and properties which are unique to the particulate state. The behavior of any particle system is determined not only by the material from which the particles are made, but also by interactions among the particles and with their environment. These interactions become increasingly important as the size of the particles decreases, and for exceedingly fine particles, smaller than about one micrometer (0.000001 meters or 0.00004 inches), these interactions dominate and we enter the realm of colloidal systems.Particle SystemsA system in which discrete entities - particles -are dispersed in a continuous medium can be regarded as a particulate system. The particles and the medium can consist of a solid, liquid or gas. The various combinations and some common examples are listed in Table 1. The properties and behavior of these systems depend on the characteristics of the particles, the nature of the medium, and the relative abundance of the two phases. In general, it is the latter which determines the kind of behavior exhibited by the system.As a general rule, the behavior of particle systems follows that of the dispersed phase (the particles) at high concentration, and that of the continuous phase (the medium) at low concentration. For example, both powders and smokes consist of solid particles in a gaseous medium. However, in a powder the solids typically occupy over one half of the total volume; in many respects powders behave like solids. In a smoke, on the other hand, the particles may take up only a few parts per million of volume, so that these systems generally behave like gases."

Jan 1, 1989

By M. G. Fleming

The professional mineral engineer is an individual of personal integrity who has undergone rigorous intellectual instruction in the scientific disciplines fundamental to his vocation; he has learnt to apply these disciplines to the discovery, mining and treatment of mineral resources and, through practical training and experience, has acquired competence and judgment to fulfil his undertakings. In the course of this development he has recognised and accepted a threefold responsibility to society, to his employer and to his profession

Dec 1, 1971

The ability to track miners and communicate with them while they work in underground coal mines is important during normal daily operations, and critical in emergency conditions. As was evident during recent incidents at underground coal mines worldwide, communication with miners and the knowledge of their location is of great importance for rescue efforts and the preservation of life. Numerous technologies have been developed, adapted, and deployed to meet tracking requirements of the Mine Improvement and New Emergency Response (MINER) Act. Evaluating the performance of these systems has proven to be difficult for mine operators, system manufacturers, and regulatory agencies. The MINER Act of 2006 requires operators to improve accident preparedness by developing an emergency response plan specific to each mine. With the recent implementation of the provisions of the MINER Act of 2006, all underground coal mines in the United States are subject to the mandates of legislation concerning communication and tracking system installation. As of June 2011, 203 new or revised tracking and/or communication systems had been approved by the Mine Safety and Health Administration (MSHA), with nearly 50 other systems or revisions in the approval process (MSHA, 2011). At that time, the available approved systems for underground coal mine use included these types: ? Leaky Feeder Communication Systems ? Fixed Node-Based Communications and/or Tracking Systems ? Wireless Node-Based Communications and/or Tracking Systems ? Medium Frequency (MF) Communication Systems ? Communication System Peripherals Other types of tracking systems have since been developed and some manufacturers are seeking approval for use in this application. Some of the new products include Through-the-Earth (TTE) systems and various radio frequency (RF) adaptations. New technologies that are currently being developed and deployed in other industrial applications should also be considered, including acoustical, optical, inertial, and hybrid technologies To date, no uniform method has been employed in the industry to effectively compare and evaluate the performance of installed systems. Neither industry operators nor regulatory agencies can accurately assess the capabilities of installed systems in the continuously changing mine environment. There is need for a uniform evaluation method that provides the ability to assess how different systems and technologies perform in various mining applications, and whether they can satisfy the regulatory requirements.

Feb 23, 2014

By J. W. Horne, W. L. Finley, A. D. Bauer, D. W. Gould

"The Bureau of Mines and the State of Colorado are cooperating in an investigation of the oil shales of Colorado. in this report the yields and the results of analyses of the oil and, gas produced from a number of oil-shale samples from the principal deposits of Colorado and other oil-shale States, are compared with samples from Scotland and Australia, where the oil-shale industry has had its greatest commercial development, and also with a sample from Brazil *here extensive oil-shale deposits are found shale samples were not selected as being representative of the different deposits, but they illustrate the wide variation in the nature of the organic matter of different oil shales.A further study is being made of the chemical composition of the shale, distribution of nitrogen and sulphur. in the products, temperatures at which organic matter decomposes, and the results will be presented in subsequent Papers, With complete data available on the chemical composition of the shales, it may be possible to explain some of the differences in the nature of the products from the various shales,Most of the work described herein was done under the supervision of M. J. Gavin. L. C. Karrick, formerly of .the Boulder laboratory, assisted in the work and gave many valuable suggestions."

May 1, 1924

By R. J. Campbell

[The steady increase of aluminum production means a corresponding increase of carbon consumption in the alumina-reduction cells. Improved petroleum techniques constantly reduce the amount of byproduct petroleum-coke production. These, trends threaten the alumina-reduction works with possible shortages of carbon, which must be supplied from some other source. In anticipation of this shortages, an investigation into the possibility of using coal as an alternative source of carbon was begun at the Northwest Experiment Station of the Federal Bureau of Mines. The investigation lit has developed bench-scale methods that produce carbon of higher purity than is required by specifications for anode carbon. Additional work will b required to bring these processes to pilot-plant seals and to prove the suitability of the carbons, produced or aluminum-anode consumption.]

Jan 1, 1956

By Frederick M. Becket

AFTER all the chronology that has been given, what is the present status of chromium steels? For the purpose of this discussion the different types of chromium steels can be divided into three classifications-those containing relatively low , percentages of chromium, say 5 per cent or less; the medium-chromium steels containing up to about 18 or 19 per cent chromium; and the steels containing still higher percentages of chromium, and some of the special alloys. Chromium has some unique effects in steel, so it is well to make a few generalizations. The affinity of chromium for carbon is great and the metal is unique in the manger in which it supplements and enhances the effects of carbon. Chromium retards -considerably the thermal transformations on cooling and exerts an opposing influence both on the absorption and precipitation of the carbides in steel. These statements make it easy to understand the fact that chromium .steels are capable of producing a hardened product at a much slower rate of cooling than is, true of plain carbon steel, and that chromium carbide or -the mixed carbides of iron and chromium do not contribute to brittleness to as great a degree as does iron carbide.

Jan 1, 1929

By R H DAVIES

Peak Gold Mine is a new gold and base metal mining project being developed by Enterprise Metals (a 100 per cent subsidiary of CRA) at Cobar in the centre of New South Wales. The Cobar district has a long history of copper and gold mining operations stretching back to the 1870s. Extensive gold and base metal mineralisation was discovered at the Peak in 1981 below a series of gold mines which had been active around the turn of the century. Evaluation of the deposit through the 1980s led to CRA's decision to develop the project for production at a capacity of 450 000 tonnes per annum in late 1992. The project has been developed with a green fields approach despite the long history of mining in the local area. This approach has lead to several innovative ideas being trialed at the site which are expected to result in the operation being a low cost producer of gold and base metals.

Jan 1, 1992

This paper describes the technical development of the Newman beneficiation plant over its 23 years of operation and how this development relates to the mine ore reserves of high-grade and low-grade ore. It also discusses the importance of the beneficiation product grades in the overall blending of shippable products from a range of mines to optimise overall ore resource utilisation. Also discussed is the importance of the ore reserve reconciliations in resource utilisation. Data is provided on the capacity and quality improvement results of the plant upgrade, carried out in 1999. This shows how the original capacity upgrade targets have been exceeded and the additional quality benefits that have been obtained from this capacity.

Jan 1, 2002

By L. D. Snyder, J. K. Russell

"The Lower Jurassic Iron Mask batholith intrudes Upper Triassic Nicola Group volcanic rocks in the Quesnellia terrane of southcentral British Columbia and hosts Cu-Au mineralization. The batholith comprises three mappable intrusive phases, including: Pothook gabbro to diorite, Cherry Creek monzodiorite to monzonite and Sugarloaf diorite. The Iron Mask hybrid forms a fourth mappable unit that makes up to 45% of the areal exposure in the batholith. It is highly variable in texture and composition and subdivided into three types; Type I and II have abundant (partially digested) xenoliths, many of which are derived from the Nicola Group, whereas Type III is xenolith-poor and shows extreme outcrop-scale textural diversity.Pothook and Cherry Creek rocks are similar in texture, mineralogy, whole rock and mineral composition and style of alteration. Contacts between the two can be intrusive or gradational. Rocks collected from these two suites have compositions that are permissive of a single magma batch, although simple crystal fractionation does not explain all chemical variations within and between the two suites. The Sugarloaf unit comprises a diverse group of amphibole-phyric rock types and is texturally and mineralogically distinct from Pothook and Cherry Creek suites.The Iron Mask hybrid represents progressive stages of physical and chemical interaction between Nicola Group country rocks and Pothook magma. Magmatic assimilation (selective or partial) is supparted on the basis of field relationships, petrographic observations, and REB compositional data. Thermal dehydration and partial assimilation of Nicola Group rocks by Pothook magma is shown to be a valid means of promoting early and extensive volatile saturation in the Iron Mask batholith."

Jan 1, 1995

By M. J. Virnig, G. A. Kordosky

Throughout time, the mining industry has been very successful in meeting the world's requirements for metals and materials while meeting the challenges of decreasing ore grades and increased emphasis on protection of the environment. This success has been due to the development and implementation of new technologies. A clear example of such a development over the past 25 years is the increasing use of leaching/solvent extraction/electrowinning for the recovery of copper from oxide and sulfide ores. The key to the successful introduction of this technology was the discovery and development of the hydroxyoxime liquid ion exchange reagents by General Mills Chemicals (now Henkel Corporation). An important role was also played by the close working relationships between General Mills Chemicals and Ranchers Exploration which resulted in startup of the first plant in 1968 and between General Mills Chemicals and Bagdad Copper which resulted in the startup of the second copper SX-EW plant in August of 1970. Following on the heels of the hydroxyoxime development came the commercialization of other new chelating reagents based on different chemical functionalities, i.e., beta-diketones, alkylated 8- hydroxyquinolines and sulfonamidoquinolines. This initial spurt of activity was then followed by a slowing of development in terms of new reagent functionalities. Activity has continued in terms of further optimization/improvement of existing reagent functionalities but the commercialization of new reagent functionalities has slackened. This observation reflects the fact that the development of new reagent functionalities for metal recovery has become increasingly more expensive such that the right combination of price and sales volume must exist in order to justify the investment required to bring a new reagent to the market place. Given the dependence of the mining industry on innovation to meet the needs of the future, one can ask how these new developments, particularly in new reagents, will occur. To arrive at an estimate of the costs involved in commercializing a new metal extractant functionality, particularly a chelating type functionality, a case study of the development of LIX ®* 34

Jan 1, 1994