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By C. D. Anderson

A variety of processing technologies exist for recovery from both primary and secondary sources of rhenium. Currently, there are no known primary rhenium deposits, thus, the method in which primary rhenium is produced is dependent on the commodity of which it is a byproduct, e.g., copper, molybdenum, uranium, etc. In addition, focus on the recovery of rhenium from secondary sources, such as alloy scraps and catalysts, is continually growing. This paper presents a review of both primary and secondary processing technologies for the recovery of rhenium. Key Words: Rhenium, Ammonium Perrhenate, Extractive Metallurgy

Feb 27, 2013

By Ulrich Paschedag

The WESTFALIA group of companies developer and manufactures underground mining machinery for complete high-performance longwalls. WESTFALIA uses a state of the art electrohydraulic system as the most important component for the realisation of today's fully automated plow or shearer longwall. The shield control unit (SCU) allows maximum custom designed software flexiblity as well as maximum hardware reliability. The master control unit (MCU) monitors shield support data as well as the plow/shearer position. By using an industry standard PC in an explosion-proof box with an intransically safe keyboard nearly unlimited software capabilities can be obtained with inexpensive hardware. Among various other modes of operation this MCU allows the monitoring and recording of data which can be transmitted to a surface computer. Production and operational adjustments can be made by the mine management based on the MCU information. Statistical analysis of the distribution of roof pressure under various conditions is also possible. The WESTFALIA automation system PM-4 gives the operator maximum flexibility and helps the mine management to run their longwall more efficiently and safely.

Jan 1, 1994

By R. F. Hinds

A pressurizing system was designed and built to apply a radial pressure of 5.000 psi to rock samples. Samples of the Bradford, Weir and Kirkwood sandstones were subjected to radial pressures parallel and perpendicular to the bedding in the system and the changes in conductivity, porosity and permeability were deter-mined. Asymptotic decreases in conductivity, porosity and Klinkenberg permeability were observed over the 0- to 3,500-psi range. From these data, the increase of formation factor over the same range was calculated. The cementation exponent expressed in the Archie equation was found to increase with pressu,re. The rate of change varied from formation to formation. Only small differences were observed for samples taken parallel to the bedding as comnared to those taken perpendicular to it except for the Bradford sand. Above 3,500 psi the data are not good enough to tell if the properties continue to fall-off asymptotically or in a different manner. A possible explanation for the probable litnit of the asymptotic rate around 3,500 to 4,500 psi is that this represents the maximum pressure which the formations have unrdergone during their geological life as a result of burial. INTRODUCTION For many years measurements have been made in the laboratory of the properties of oil-bearing sandstones with little consideration being given to whether these properties had been changed when the samples were moved from their original position in the ground to the laboratory. Relatively little has been reported in the literature on the effect of pressure on the properties of sandstones. The changes in permeability for eight typical consolidated oil-bearing sandstone samples with overburden pressure (0- to 15,000-psi range) was presented by Fatt and Davis' in graphical form. In 1953 Fatt' also reported the relationship between porosity and overburden pressure for four typical consolidated oil-bearing sandstone samples (0- to 5,000-psi range). Fatt later described the changes of formation factor and porosity of 20 typical oil-bearing sandstone samples with overburden pressure changes (0- to 5,000-psi range) giving the values of the coefficients and exponents in the Archie' equation, and the more general Winsauer equation', where C, k and m are empirical constants, F is the formation factor, and + is the porosity. During the experiments of this investigation the core was contained in a neoprene rubber sleeve as shown in Fig. 1. It was held between two steel end members which were mounted in a steel cylinder. The unassembled pressure cylinder with its component parts is shown in Fig. 2. The core was insulated from the two steel end members by a Teflon sleeve with a small hole in the

Rehabilitation, reclamation and restoration are all terms used to describe the repair of land after mining. Here, restoration is used to mean restoring the land's original use, capability or productivity. Effective restoration is dependent on good planning before mining commences and must include a clear definition of post-mining objectives. The physical condition of the land within the mining licence was that of an imperfectly drained soil in permanent pasture, supporting a seasonal supply dairying unit. During the mining process, the soil layers were separated, with the topsoil stockpiled separately. As part of the restoration process, the land was recontoured to encourage surface drainage, with topsoil spread evenly over the recontoured tailings. Low grond pressure machinery was used to minimise soil compaction, with light discing and harrowing used to increase water infiltration. A permanent pasture was sown, with weed species controlled by spraying, both before and after pasture establishment.  Soil testing has been used extensively to ensure there were no nutrient deficiencies that good compromise pasture establishment and performance. Controlled grazing practices were used to ensure that the sown pastures became well established.

Jan 1, 1998

By E. G. King

As low-temperature heat-capacity and entropy data were available for only one sesquisulfide (cerium sesquisulfide), it appeared desirable to augment the information for this class of compounds by measuring the sulfides of antimony and indium. In addition a pressing need existed for data on indium sulfide to supplement vaporization studies in progress in the Department of Mineral Technology, University of California. This Bureau of Mines paper reports low-temperature heat-capacity measurements and entropy evaluations at 298.15° R. of antimony sesquisulfide of stoiehiometric composition (Sb2S3) and of indium sesquisulfide which was somewhat deficient in sulfur (In2S2.93). The data for the latter substance were adjusted to correspond to the stoichiome tric composition (In2S3 ) . Indium sesquisulfide has a lower entropy at 298.15' K, than either antimony sesquisulfide or cerium sesquisulfide, in line with the higher atomic density of the indium compound.

Jan 1, 1962

By S. Rupprecht

"This article addresses the prevalence of poor public reporting practices of coal exploration results, coal resources and coal reserves in southern Africa. Currently, the reporting of coal tonnage without supporting coal qualities or saleable tonnes and quality is a poor reporting practice that occurs far too often. Not all coal is equal — therefore it is extremely important that investors or potential investors are provided with the full details of both run-of-mine (ROM) and saleable coal tonnage, their associated qualities and other material and relevant information.Competent or qualified persons should note that publicly reported information should be sufficient to enable an informed reader to make a reasonable and balanced assessment of the significance of the information provided. “Companies are encouraged to provide information in their public reports, which is as comprehensive as possible (CRIRSCO, 2013).” However, too often this isn’t the case, and material matters are either not reported or inadequately disclosed.According to the South African National Standard (SANS) 10320:2014 draft document, “tonnage and coal quality that will be available for sale, either in the raw ROM state (raw saleable) at a specified moisture content, or after beneficiation of the ROM coal by processing operations to produce materials at specified qualities, size ranges and moisture contents. The assessments must demonstrate that at the time of reporting, the marketing of the products is reasonably justified. The basis of the predicted practical product yield to achieve the saleable coal reserve must be stated. The moisture basis of reporting shall be stated.” An example as to why coal qualities are so important to the public, the requirements of South Africa’s electric public utility (Eskom) power stations are detailed in the followint paragraphs. The Kendal power station, commissioned in 1988, operates at a calorific value (CV) range of 19 to 20 MJ/ kg, an ash content between 29 and 34 percent and volatiles between 20 to 21 percent. Other power stations, such as Kriel or Hendrina, may require different qualities, such as a CV range of 22 to 23 MJ/kg, an ash content between 20 and 28 percent and volatiles between 22 to 23 percent. Thus, in terms of domestic saleable coal, it is not just about reporting the coal qualities but also informing the investor as to which power station the coal is intended to be sold as “boilers are designed to burn particular qualities of coal” and “it is not always possible to transfer coal between stations because of different quality requirements at each station (Chetty, 2010).” Sulfur content is another important quality with the ideal coal content having a quality of less than 1 percent sulfur."

Jul 1, 2019

By Kenneth G. Skinner

The rapid growth of the metallurgical, chemical, and allied industries on the Pacific coast just prior to and during the war caused a sudden increase in the demand for refractories, which was the immediate cause of a revival in interest in refractory clays available on the Pacific coast, particularly in the Pacific Northwest. Population increases and shortage of shipping facilities caused an increase in the amount of various ceramic materials and products used and produced on the Pacific coast, with accompanying demand for information regarding sources of clay. In an effort to supply part of this information, the Bureau of Mines, in cooperation with the College of Mines, University of Washington, started a program in 1944 to test the refractory and other properties of clays from seven Pacific Northwest deposits that had been drilled and sampled as part of the Bureau of Mines alumina from clay investigation. Figure 1 shows the location of these deposits.

Jan 1, 1949

By Dale R. Ralston

This investigation was divided into two major phases. Phase I of the study was an examination of the occurrence and production of acid water within the Bunker Hill Mine in northern Idaho. The second phase of the project involved the study of water movement through an abandoned tailings pile. Mineralogy and hydrogeology were determined to be the two most important factors in the acid mine drainage problem. Low pH water was formed in the mine in areas of lead-zinc ore rich in pyrite. Water movement in the mine was important in the production of acid and the transportation of heavy metals. Areas of recharge to the mine were identified. A data collection network was installed to monitor water quality and quantity changes. The quantity of acid drainage from the mine was found to vary directly with surface runoff events. The study of the abandoned tailings pile was performed to determine the characteristics of water movement through the tailings material and the resultant impact on the hydrologic environment. The Page Tailings Pile, abandoned in 1969, was utilized as a study area. An extensive network of piezometers and meteorological data collection sites were installed in and near the pile. Data collected to date indicate the presence of a ground-water mound under the east half of the pile. Some transfer of ions from the tailings pile to the ground-water system has been detected.

Jan 1, 1973

By Robert J. Pokora

This report summarizes the work performed under USBM Contract No. J0100038, "Demonstration of Noise Control Techniques for the Crushing and Screening of Nonmetallic Minerals." The objectives of the program were to: a. Identify the prevalent sources of crushing and screening noise in portable and stationary plants b. Design retrofit noise control treatments for those sources c. Field test control treatments under actual operating conditions. A census of the nonmetallic industry was performed to determine the number and types of crushing and screening equipment. Based on the census, eight plants were selected and surveyed to assess the variety of noise sources, determine the worker noise exposure to those sources, and to identify possible constraints that had to be considered in designing and installing the retrofit controls. Three plants were selected from those surveyed and retrofit noise control treatments were designed, including: a. A primary crusher operator control booth b. Screen decks made of resilient cloth c. Screen feedbox impact pads d. Rubber feed plate for secondary crusher e. Rubber feed chute linings for secondary crusher f. Noise attenuating curtain for secondary crusher. A new primary crusher control booth was installed at one plant, and the operator noise levels were reduced from 97 dBA to 78 dBA. Screen noise at the two secondary crushing plants was reduced by 3 dBA to 7 dBA; crusher noise was reduced by 5 dBA at one of these two plants. Noise levels at normal outside operator and cleanup locations were reduced by 4 dBA to 7 dBA at one secondary plant, but operator/cleanup noise levels were not significantly reduced in the second plant due to rapid wear of installed materials. At one of the two secondary plants the retrofit noise control materials displayed excellent wear characteristics. The rapid wear of retrofit materials at the second plant was due to improper materials being supplied and changing circuit conditions.

Jan 1, 1982

By Nobuzwe Makhotla, Sasha Boskovic, Steve Hearn

"Mineral separation efficiency in flotation depends, to an extent, on the type of frother used. Huntsman develops and manufactures unique frothers which are suited for mineral processing applications. This paper discusses the Huntsman approach to understanding the industry’s flotation frother requirements to optimise frother selection and introduce the Huntsman’s POLYFROTH® frother range. Specific case studies where the frothers are used are discussed. INTRODUCTION Froth flotation is a process of using bubbles to separate minerals based on their relative affinity for water. Bubbles are induced in the slurry through aeration. Chemistry is used to aid the flotation process and chemical reagents are added to enhance the separation process. The flotation reagents include frothers, collectors, surface modifiers and pH regulators that control physical and chemical conditions of solid, air and liquid phases, respectively. As described by Harris (1976), the key effect is that of bubble size control by way of preservation of the generated bubble size, which is attributed to the coalescence inhibition by the presence of the frother on the bubble surface. Following this, the frother must stabilize the froth phase. Frothers are also added to create optimal conditions for bubble creation and stability by decreasing the surface tension of the water. Depressants may be added, depending on the ore treated, to assist the hydrophilic particles to stay in the water phase. Clay particles may need to be dispersed to prevent them from attaching to the bubbles. Hydrophobic particles attach to the bubbles and are carried to the surface of the slurry where froth is formed. It is important for these bubbles to have the mobility to carry the mineral to the launder where the concentrate is collected. Types of Frothers There are generally three main groups of frothers used in froth flotation. Alcohol Type These frothers have a molecular structure that usually includes 5 to 8 carbon atoms in a hydrocarbon chain and their solubility in water is limited. Methyl isobutyl carbinol (MIBC) belongs to this category and is widely used in the industry. The weaker alcohol-type frothers are more selective and typically suited to finer particles. There are three sub-categories under this group: aliphatic, cyclic and aromatic alcohols."

Jan 1, 2015

By L. R. Herrmann

The most fundamental feature of fracture is that it involves separation. Such separation can arise by either separation of molecules, more or less along the line joining their centers (tension), or by d sliding separation roughly perpendicular to that line (shear). Theoretically, a perfect crystal could never be broken by the application of perfectly axial compressive stress (until some sub-molecular actions occur). In tension fields the calculated forces between molecules are extremely high. Consequently, calculations based on the forces known to exist in materials at the molecular and crystalline levels always lead to strengths which are two or three magnitudes higher than the strengths obtained in service or in the laboratory. It has been a major problem, therefore, to explain: (a) How fracture can occur in compressive stress states. (b) Why the observed strength of a material is always much lower than its calculated strength.

Jan 1, 2012

By A. M. Hearn, J. G. Roos

Energy consumption, being a large proportion of the input of the ferroalloy production process, can be measured in terms of the efficiency with which the energy is utilized and the effectiveness with which it is used. The efficiency of the usage of energy revolves around the specific consumption of the energy for the production of the alloy, which encompasses the thermodynamic aspects of the process and is more of a metallurgical function that will not be addressed further in this paper. The effectiveness with which the energy is utilized is determined by the optimisation of the electricity supply from the utility (in this case Eskom). The South African electricity supply industry is on the brink of considerable restructuring, implying changes in ownership, structure and regulation. In other countries, however, restructuring has often seen higher prices. Owing to the diversity of growth prospects in South African markets, Eskom is turning to new market management and generation strategies. In future, Eskom will develop pricing strategies to increase demand from attractive customer segments such as paper & pulp, iron & steel, aluminium, and other metallurgical industries. There will be a broader spectrum of product offerings, including dynamic pricing options and demand-side management incentives. In a future electricity market that will become more dynamic and demanding, it will become increasingly important for electricity consumers to optimise their electricity supply. There are many facets in optimising the electricity supply, which include optimal utilisation of the tariff, integrating energy cost management into the production planning process, implementation of demand-side management actions, modelling, scenario planning (.what-ifs?.), optimisation, maintenance scheduling coordinated with the tariff periods, etc. This paper gives consideration to the status of the development of technology at the manganese alloy works of Samancor at Meyerton, South Africa in order to increase the effectiveness with which energy is utilized.

Jan 1, 2004

By Georgene Renner, William R. Yernberg, William Gleason

American Commercial (ACI) offers a selection of ground control solutions. Beginning with steel liner plates installed in the Gratiot Avenue sewer system in Detroit, MI 1920, ACI is one of the leading designers and manufacturers of underground steel supports in North America. ACI is also a leader in fire-proofing underground structures with its Promat Fire Protection Boards. The sandwich panels have been used in many new and retrofit tunnel and underground construction projects worldwide. Ease of installation and replacement, cost effectiveness and superior performance have made this product line the premier choice of owners and designers for structural protection, fire-life safety requirements and architectural finish needs.

Jan 1, 2007

By Daniel Mallette, Richard Goodridge, C M. Lownds

Despite a world of mobile devices that has many of us taking the ability to communicate wirelessly for granted, an in-hole wireless initiation system was thought to be not viable. The known and common wireless communication techniques are not suited to this application. To overcome this, we have developed cutting edge technology to communicate to our initiating devices more than 1km through solid rock.

Jan 1, 2016

A large lab apparatus was designed using a scale-down methodology based on the design legacy of the current FLSmidth commercial forced air flotation machines. This new apparatus, along with a new test methodology, was used to evaluate new rapid prototype concepts. The apparatus was designed to monitor bubble size, power, pumping capacity, Jg, velocity profiles, froth character, and tip speed. The methodology developed follows a sequence that goes from hydrodynamic tests and solids suspension tests to a flotation kinetic test. This methodology has been demonstrated to be a good tool to determine the effect of machine design changes on flotation.

Jan 1, 2012

This work presents: 1.) the results obtained from measurements of temperature profiles in pillars and at working faces of three coal mines located in Colorado and New Mexico, 2) a comparison of the experimental results with theoretical predictors based on linear heat flow models, and 3) temperature profile predictions based on a two dimensional coal mine model with an inclined crack located in the roof or wall of the opening. The thermal properties of the coal and shale samples taken from the mines were used as input data for the computer model. Good agreement was found between the measured profiles and the theoretical values obtained with the one dimensional model. The two dimensional model results show that a visible crack (0.01-0.07-ft thick) in a coal roof causes a surface temperature difference from 0.2 to 1°F at the edge of the crack for rock exposed to air from 1 hr to 288 hrs and with the air to rock temperature differences from 2°-6°F. A temperature difference of 0.3 °F was found between solid and broken rock in a shale roof with a 0.03-ft thick crack inclined 45° to the horizontal after a ventilating time of 48 hrs and the air to rock temperature difference of 2.1°F.

Jan 1, 1972

By R. Grandori, L. Pellegrini

The construction of the La Joya hydropower plant (Costa Rica) was awarded by the Spanish power company, Union Fenosa, to the Italian Joint Venture formed by the companies SELI SpA and Ghella SpA. The project, located in a mountainous region of central Costa Rica, includes a 7.9-km-long head race tunnel having an excavation diameter of 6.18 m. A double-shielded TBM was selected to perform the tunnel excavation, which involved mainly volcanic rocks in variable but generally very weak conditions. The tunnel crossed long and continuous sections in completely weathered rock masses with no residual cohesion and with high water inflows. The paper describes and analyzes: The special methods adopted to overcome these sections with the TBM includ-ing face stabilization by chemical grout and foams as well small by-pass tunnels in the crown combined with TBM advance/support The grouting design and the grouting method that was implemented to meet the waterproof design specifications and restore the original groundwater level in the mountain The additional geological investigations performed to improve the knowledge of the rock mass in front of the TBM and the outcomes of these investigations The performance of the TBM in different ground conditions and on average along the entire tunnel Finally, the author’s comment about the possibility of implementing and improving the technologies experimented with in this project in future similar applications.

Jan 1, 2007

By Orlando C. Gaspar

Abstract - The presence of fine-grained mineral intergrowths, the complex distribution of deleterious minor elements, and the variable base-metal contents in some assemblages commonly pose technical problems for the processing of volcanogenic massive sulfide ores. The beneficiation of most massive sulfide ores from the Iberian Pyrite Belt requires extremely fine grinding to liberation sizes of K80 = 15 µm to 25 µm. For several deposits, mapping of the ore types and metal zoning patterns has shown that the different ore types are distributed as ore lenses within the massive sulfides. Mineralogical, textural, and metallogenetic studies have provided an understanding of the distribution of both the vertical and the horizontal metal zonation in the orebodies. Because the efficiency of ore processing is affected by ore textures, and because the same mineral commonly has different textures and varies in chemical composition, a relationship between textures of the feed and the middlings must be established for all ore types defined at the deposit scale. Quantitative mineralogical methods have been developed to provide, on a timely basis, the information needed to optimize the concentration processes for the massive sulfide ores at the Aljustrel and Neves-Corvo deposits, Iberian Pyrite Belt, Portugal.

Jan 1, 1997

By Orlando C. Gaspar

The presence of ?ne-grained mineral intergrowths, the complex distribution of deleterious minor elements, and the variable base-metal contents in some assemblages commonly pose technical problems for the processing of volcanogenic massive sul?de ores. The bene?ciation of most massive sul?de ores from the Iberian Pyrite Belt requires extremely ?ne grinding to liberation sizes of K80= 15 µm to 25 µm. For several deposits, mapping of the ore types and metal zoning pat-terns has shown that the different ore types are distributed as ore lenses within the massive sul?des. Mineralogical, textural, and metallogenetic studies have provided an understanding of the distribution of both the vertical and the horizontal metal zonation in the orebodies. Because the ef?ciency of ore processing is affected by ore textures, and because the same mineral commonly has different textures and varies in chemical composition, a relationship between textures of the feed and the middlings must be established for all ore types de?ned at the deposit scale. Quantitative mineralogical methods have been developed to provide, on a timely basis, the information needed to optimize the concentration processes for the massive sul?de ores at the Aljustrel and Neves-Corvo deposits, Iberian Pyrite Belt, Portugal.

Jan 1, 1997

By J. E. Nesset, S. R. Rao, J. A. Finch

"For base metal sulphides, iron rejection starts in mineral processing. This review focuses on changes in plant practice specifically to improve iron sulphide rejection by control of contaminant ion effects and discusses selected general innovations in mineral processing that can be expected to play a role. One group of changes to control contaminant ions is in size reduction (the use of stage grinding and inert stirred milling) and another is in system chemistry (order of reagent addition and exploitation of the flexibility of sulphoxy reagents). Plant examples illustrate the successes, indicating that there are several options available. The general innovations start by considering the new tools for measuring gas dispersion properties and quantifying froth characteristics by imaging. Examples of their application to improve concentrate quality illustrate the potential. Other innovations stress adapting geostatistics to model variation in milling and flotation response to provide feed forward control and rigorous application of statistical experimental methodology in plant test work. An example from one concentrator shows improvements in concentrate quality from application of basic principles can be impressive.INTRODUCTIONThe more iron control (rejection) that can be accomplished in mineral processing the lower the subsequent metal extraction costs and environmental implications of iron disposal, particularly in hydrometallurgical processes. Iron rejection has been a contributing target to periodic attempts to apply mineral processing to nickel laterites and bauxites but the prime application is control of pyrite and pyrrhotite (iron sulphides) in the treatment of sulphide ores by flotation. In this paper some new concepts and innovations introduced in sulphide flotation plants over the past ten years or so (i.e., since a previous review [1]) will be outlined with examples of how they have contributed to improved “iron control”.To increase rejection of iron minerals, first the recovery mechanism should be understood. There are four principal ones, two physical in origin: 1, via locked particles (i.e., flotation of composite particles due to insufficient size reduction to liberate the minerals) and 2, through entrainment in the water reporting to the float product (an unselective process); and two originating from a response to the system chemistry: 1, true flotation (i.e., iron sulphides becoming hydrophobic) and 2, as a result of iron sulphides forming aggregates with hydrophobic particles (e.g., ”slime” coatings). There has been considerable effort to diagnose which of these dominates iron sulphide recovery; in many cases it is due to “chemistry”, in particular true flotation. The flotation effect often appears related to contamination by metal ions [1]. This can reduce selectivity in two ways: 1, metal ion species may activate iron sulphides, or 2, cause general depression which demands more vigorous flotation conditions (e.g., additional collector) with consequent loss of selectivity. This is where the review will start, by considering ways to control contaminant ions."

Jan 1, 2007