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By E. Dendy Sloan

An overview of hydrate properties is given, with emphasis on unusual deviations from ice, the most common solid water form. Reliable sample preparation and reproduction of in situ hydrates provide the foundation for all hydrate science and engineering. Relations are given to connect the three domains in the title: (1) micro-scopic properties measured with Raman, NMR, and diffraction spectroscopy, (2) meso-scopic properties measured with single crystals, and (3) macro-scopic properties measured with pressures, temperatures, volumes, etc. A principal illustration relates micro-scopic and macro-scopic domains. Experiments provides the basis for improving statistical thermodynamics model for these compounds. To date, this model is one of the most commonly used industrial statistical thermodynamics applications, based upon the classical model of van der Waals and Platteeuw (1959). Microscopic measurements and simulations indicate model assumption improvements, resulting in the next generation of the statistical thermodynamics for improved macroscopic property prediction.

Jan 1, 2002

By Steven Wright

The reduction of a slag produced 6om the recycling of lead batteries was studied in a kilogram scale laboratory investigation by reacting with graphite at temperatures of 1180 and 1200°C. Simultaneous reduction of PbO, Fe203, Sb203 and As203 occurred with the Sb and As reporting to the metal while the lead content in the slag was above 2 wt%. The Sb and As distributions between metal and slag were strongly affected by temperature and slag oxidation state. The rates of reduction of PbO and Sb203 increased with increasing slag basicity and temperature and decreased as the PbO content in the slag decreased. The reduction rate of PbO from these slags was similar to other industrial lead slags at the same CaO/SiO2 ratio and temperature. The implications of the behavioural similarities of the antimonous slags during reduction with carbonaceous reductants and other lead slags are briefly discussed.

Jan 1, 1994

By J. A. Herbst

Professor Klaus Schönert and his students used fundamental physics to develop many of the principles required for the design and scale-up of "Gutt Bett Zerkleinern" devices such as the high pressure grinding roll (HPGR) or the high pressure roll crusher (HPRC). As the equipment evolved so have the tools used for its selection and analysis. In the current paper discrete element modeling (DEM), Metso's proprietary Fast Breakage simulations, and Schönert's packed bed piston test are combined with energy based population balance models (PBM) to yield an alternative to ore characterization and equipment selection by pilot plant testing. The resulting methodology is used to take the next step in understanding these devices with a view toward predicting plant performance. This paper describes a journey beginning with precise modeling of a small HPGR including stud geometry and system hydraulics. A key to predicting performance is the accurate modeling of individual particles, their motion in the machine, the probability of breakage and redistribution of fragments, and the inter-particle breakage events that occur between the rolls at different pressures, speeds and moisture levels. Advanced DEM simulations and particle breakage characterization methods provide the necessary technology. The resulting combined models were validated using a small diameter laboratory scale unit. The validated physics based model was used then used to predict the performance of plant scale units using a specific energy based scale-up method. Scale-up results are analyzed in terms of power draw, throughput, and discharge product size distribution.

Jan 1, 2012

By B. I. Matshediso, J. Kaavera, E. Shemang, T. K. Dintwe, L. S. Teseletso, K. Fichani

The minerals sector continues to draw attention from policy makers who would want to see both old and new mineral projects add value to the minerals in the host country. The current technological development in the leaching of manganese oxide ores to produce a high-purity manganese sulphate monohydrate, a compound that is used in the manufacture of batteries for electric vehicles or long-life storage cells for the renewable energy market, has led to junior mining companies spearheading this technology in new projects across the globe. In this paper, we researched the high-purity manganese sulphate monohydrate project pipeline and used projected production volumes and C1 cash costs to construct the industry supply curve for six projects, including the K.Hill project owned by Giyani Metals Corporation near Kanye, in the southern part of Botswana. The aim was to determine the ideal conditions that would provide a comparative advantage for further local value addition to high-purity manganese sulphate monohydrate and to the end user product. The results showed that while the estimated C1 cash costs would place the K.Hill project as the second highest cost producer from among five projects, it would nonetheless have healthy profit margins due to the high projected price of high-purity manganese sulphate monohydrate. The study recommended policy options, which, if implemented, could further encourage the exploitation and value addition of battery metals in Botswana.

May 27, 2025

By Alfred E. Pugsley

PAYMASTER CONSOLIDATED MINES, LIMITED, began an investigation into the economy and use of detachable bit drill-steel in June, 1937. This investigation has continued to the present time, and was made necessary by transportation and distribution difficulties that had arisen through the use of standard steel in three widely separated mine areas serviced by a central steel-sharpening shop. Detachable bit drill-steel performance was first studied in the workings of No. 2 mine, where the rock being drilled was composed mainly of porphyry or tourmaline, and where standard drill-steel transportation costs had been excessive. The results obtained in this early work definitely established the economy of detachable bit drill-steel at No. 2 mine. This conclusion was reached when the 're-grind' system of re-sharpening dulled detachable bits was 1n use. Preliminary observations on the performance of detachable bit drill-steel in the quartz-carbonate veins of No. S and No. 6 mines gave encouraging results, and warranted a large-scale investigation under practical mining conditions. All drilling operations were gradually changed over to use of detachable bit drill-steel. This change was completed by February, 1938.

Jan 1, 1939

By Roy A. Grancher

?The Horn of Plenty seems to have sprung a leak?.? anonymous For the first time in the Nation's peace-time history, shortages have become a way of life for the United States. Such words as scarce, tight, and critical are used in regard to supply, leading to priorities, allocations, and possible rationing as make-shift attempts to satisfy demand. Almost every day a new type of shortage appears in another product area that has traditionally been taken for granted as being in perpetual abundance. The range of coverage extends from basic commodities such as oil, chemicals, cement, steel, copper, cotton, etc., through to machine tools, motors, bearings, electronic components, etc. , to those finished outputs that satisfy our fundamental requirements for food, clothing and shelter. Signs of the times appear in cancelled airline flights, unfilled lines at gasoline stations, no available home freezers, lengthy delays in any furniture deliveries, or to that little old lady seen walking out of a local supermarket clutching her hoard of twenty rolls of toilet paper. What a sad commentary to have to make about our Land of Plenty, so long the envy of the World for its material wealth -- and today with its initials "U. S." seemingly standing for ?Unlimited Shortages.?

Jan 1, 1974

By H. B. Carroll

The Bureau of Mines has designed and built a controlled-environment test chamber specifically for instrument evaluation in simulated work atmospheres. The atmosphere inside the 300-liter stainless steel chamber can be controlled at any selected temperature and relative humidity in the range of 2° to 93° C and 20 to 95 percent, respectively. Instruments placed inside the test chamber are subjected to an atmosphere at a preset temperature and humidity containing various concentrations of toxic gases such as CO, C02, NO, NO2, S02, and H2S. Toxic gas losses resulting from wall reactions, monitoring instruments, and instruments under evaluation are compensated by the use of a dynamic gas blending system.

Jan 1, 1973

By Zhenfeng Zhou, Qingguo Xue, Jingsong Wang, Guang Wang, Yuanyuan Zhang

The oxygen blast furnace is a new technology for ironmaking, where the oxygen and CO2-stripped blast furnace top gas are blown into the blast furnace replacing the conventional hot air. The oxygen blast furnace could reduce the consumption of coke and emission of carbon dioxide. In this chapter, a three-dimensional numerical model was developed to simulate the lance-blowpipetuyere-raceway region of a blast furnace, and the flow and combustion behaviors of coal particles were investigated based on an oxygen blast furnace. Compared with the traditional blast furnace, the combustion characteristics in the raceway of the oxygen blast furnace were different. In addition to the combustion of coal and coke, the combustion of large amounts of reducing gas was included. The coal combustion of different oxygen content (70, 80, 90, 100%) were investigated. The simulation results indicated that the coal burnout was only 21.64% at an oxygen content of 70%, a decrease of 51.52%, compared with a traditional blast furnace. The coal burnout was increased with the increase of oxygen content. When the oxygen content is 100%, the coal burnout was 90.38%, an increase of 17.22%.

Mar 1, 2017

By Brian Hart, Rong Fan, Roger Smart, Andrea Gerson, Ning Xu

A complete strategy has been developed for identification of the reasons for losses in recovery and/or grade, due to changes or complications in mineralogy and in mineral surface conditioning, and their subsequent correction. The sequence of methods starts with comparison of mineral phases between QEMSCAN/MLA (compositional) and Rietveld XRD (crystalline diffraction) with bulk assay reconciliation. This methodology has recently led to identification of unrecognised amorphous content (12-40 wt.%), previously attributed to crystalline phases, in the fine fraction (<35 µm) of some problematic flotation feeds. Attached amorphous silica, talc- and chlorite-like fines have direct influence on the hydrophobic/ hydrophilic ratio on value mineral surfaces adversely affecting flotation. SEM/EDS is used in the backscattered imaging mode to determine possible problems with liberation (e.g. remnant local locking), not detected in standard liberation analysis, resulting in gangue flotation. EDTA extraction is used to assess bulk feed pre-oxidation and sequential oxidation product loading through the circuit. Changes in circuit solutions are assayed with speciation modelling of precipitates and potentially adsorbing species. ToF-SIMS with principal component analysis is then used to correlate surface species with specific minerals and can be used to assess the effectiveness of specific reagents particularly collectors. This approach identifies unwanted activating species and interference with value surfaces by adsorbed hydrophilic ions, precipitates and fine particles. When the interference or ineffective reagents are specifically identified, remedial action can be targeted. This method has identified residual talc-like layers (<10 nm thick) inducing gangue flotation of pyroxene and chromite in PGM flotation. Recent case studies of application of the full methodology to losses of molybdenite at KUCC and to sphalerite activation in the Cu/Pb circuit at Brunswick Mines with remedial action are discussed.

Jan 1, 2014

By Charles E. Robertson

As it becomes more and more apparent that our nation must place a great deal of reliance on coal as an energy source in the coming decades, prospecting for new reserves Un Missouri and other states in the Western Interior Region is increasing. As more and more of the known reserve becomes committed to existing or planned projects operators will be forced to look beyond the fringes of existing coal fields for additional reserves. Perplexing geologic problems invariably confront all prospectors and are particularly bothersome to those new to a particular area. It is the purpose of this paper to alert prospective operators to geologic problems likely to be encountered and to offer guidance in the recognition and solution of these problems. Particular emphasis is placed upon geologic structure and washouts. Other geologic problems have been discussed in a previous paper.

Jan 1, 1977

By Lawrence Devon Smith

"The concept of risk is well established in the mining industry. It is acknowledged when estimates of reserves are expressed as proven or probable, when mining and metallurgical recoveries are applied to the ore, and when contingencies are added to costs. However, it is difficult to provide a quantitative assessment of risk. The significant sources of risk in a mineral project and how these are addressed in project evaluations are discussed. The discount rate is examined as a fundamental means of reflecting risk in discounted cash flow evaluations. Current industry practice is discussed, and a methodology for the analysis of risk levels is proposed that assesses the constituent components of the discount rate: real interest, mineral project risks, and country risk.IntroductionThis paper examines the components of the discounted cash flow discount rate and proposes a method of estimating project-specific discount rates. The motivation for this work comes from experience of project evaluations in which owners and purchasers had agreed on virtually every aspect of the evaluation except how much the project was worth. Agreement was reached on reserves, grad~, recovery, capital costs, operating costs, taxes, and, by combining these components, even on the fmal cash flow values. The only difference in opinion concerned the discount rate to be used in the calculation of the net present value. Depending on the life of the project, such differences of opinion can cause a variation of more than 50% in the value placed on a project! This is illustrated in Figure 1."

Jan 1, 2003

By M Haest

This study demonstrates the application of HyLogging™ technologies for mineralogical characterisation of different iron ore types throughout the Hamersley Province (Western Australia), including a channel iron deposit (Murchison Metals Ltd) and bedded iron deposits in the Brockman and Marra Mamba Iron Formations (BHP Billiton Ltd).Drill core from these deposits was analysed using CSIRO’s hyperspectral drill core logging systems (HyLogging systems), which are commercially available at the AMDEL and AMMTEC laboratories in Perth (Western Australia), through a leasing agreement. These HyLogging systems provide high resolution photographs at 0.1 mm pixel resolution as well as visible and infrared spectroscopic refl ectance data at 1 cm spatial resolution. The minerals identified include haematite, goethite and its subtypes (ie vitreous and ochreous goethite), AlOH-clays (kaolinite, Al-smectite and white mica), carbonates, gibbsite, chlorite, amphibole and hydrated silica as well as water content. The abundance and composition of these minerals was established from the spectral data and was validated against XRF analyses.The full potential of HyLogging systems in the iron ore industry is only starting to be unveiled, but some major benefits have already been demonstrated:• HyLogging systems can delineate different ore zones by mapping the vitreous and ochreous goethites. This has a potentially large impact in mine planning and operations, as hard, vitreous goethite and soft, powdery, ochreous goethite have different processing characteristics that can affect plant throughput if not carefully managed.• HyLogging mineralogy can also be used to support stratigraphic interpretations of the host, for example in subdividing the Dales Gorge 1 - 4 submembers of the Brockman Iron Formation.• HyLogging can have a potentially signifi cant impact on waste rock characterisation, as many of the waste materials can be identifi ed and quantifi ed with hyperspectral data (eg clay-type,• hydration state).• HyLogging can provide accurate three-dimensional (3D) mineralogy to iron ore companies that will empower them to improve future exploration and resource planning.• Application of high resolution photography to further improve ore deposit domaining is also to be considered.

Jul 11, 2011

By Dr. Calvin J. Konya, Anthony Konya

Beginning on the Niagara Power Project, presplitting became a widely used blasting technique to obtain smooth walls in mining and construction projects reducing scaling, creating more stable pits, allowing the application of slope steepening to reduce waste removal and increase mining depths, and increasing the safety of mine and construction workers. This technique has been minimally studied in comparison to production blasting and currently two separate theories are present on the mechanics behind the presplit. The first is that shockwave collisions between boreholes cause a tension zone to develop causing the split formation. The second is that gas pressures build in the boreholes causing hoop stresses between holes leading to a presplit formation. Practical blasting methods in presplitting such as propellant presplitting and precision presplitting would not be applicable based on the shockwave theory yet are widely used and documented in the industry. Along with this, modern research using a borehole simulation device and advanced pressure gauges have allowed the authors to obtain true borehole pressures in decoupled blastholes. This paper will present this research which correlates the borehole pressure to variables such as the Young's Modulus and Tensile Strength of various rock types giving blast designers the ability to design a presplit to function in many rock conditions, including weak rocks such as siltstones and mudstones.

By John C. Niedzielski, A. Frances Ackerman

The existing US-70 Bridge over the Gila River at Bylas, Arizona is planned to be replaced due to its current poor condition. The replacement bridge is planned to be a 15-span, 1,904-foot (580 meter) long bridge, the third-longest bridge in the state highway system. Within the Gila River floodplain, granular alluvial soil is underlain by cohesive lacustrine soil; bedrock was expected due to nearby terrain but not encountered within the geotechnical exploration depth of 166.5 feet (51 meters) or less. Based on the anticipated loading conditions, design scour depths and the soil conditions, the full structural loads are carried by large diameter drilled shafts; therefore accurately determining the axial capacity of the proposed drilled shafts has important practical and safety implications. The conventional methods for axial capacity determination may be overly conservative to use for design in the site’s layered granular and hard clay soils. An Osterberg cell load test was performed to obtain detailed information on the load transfer from the drilled shaft in side friction and base resistance to allow optimization of the bridge foundation design. The fullscale field test played a significant role in the design of the project’s deep foundations, notably, by incorporating the specific subsoil properties and consequently, an exact prediction of the load-settlement behavior under loading. This paper provides the results of the geotechnical site investigations, drilled shaft load testing procedures, and shaft load distribution from the load test results. Comparisons were developed between predicted axial capacities of drilled shafts using several design methodologies and the axial capacity measured from static load testing. The load test results showed that underestimation of the axial capacity is evident using conventional methodologies. The exact prediction of the load-settlement behavior under loading combined with a site-specific design approach, resulted in a substantial reduction of foundation costs due to reduced drilled shaft dimensions.

Jan 1, 2017

By Anthony Konya, Calvin J. Konya

This paper will present this research which correlates the borehole pressure to variables such as the Young's Modulus and Tensile Strength of various rock types giving blast designers the ability to design a presplit to function in many rock conditions, including weak rocks such as siltstones and mudstones.

Feb 1, 2020

By D. W. Gunkle

Processing of various ores and materials in a reducing atmosphere has been done for many years. However, the typical device currently used is a large, often high maintenance, expensive piece of equipment; the rotary kiln. While it is a very reliable and a proven technology, the rotary kiln also has its limitations. It is limited by its ability to process very fine materials without creating a huge dust loss to the air pollution control equipment. This leads us towards the development of an alternate technology; the Gas Suspension System. Gas suspension preheating of various materials has been in commercial use since the early 1950&apos;s, but recently has been expanded to include Gas Suspension Reduction. Laboratory experience has proven successful on several materials; Nickel Laterite Fines, Iron Ore Fines, Fluorspar, and Clays. The gas suspension reduction system has many advantages over the conventional reduction kiln when processing fines. They are; lower cost, more fuel efficient, able to process fines, less real estate required, etc.

Jan 1, 1998

By Peter B. Dowden, David T. Cass

A shield on a tunneling machine has two basic purposes. Firstly to provide temporary support in unstable ground, maintaining the integrity of the bore and protecting the operators, and secondly, in conjunction with other sealing devices, to prevent the ingress of water. In any specific tunnel, unstable ground and water may or may not occur together. Further, there are a number of different ground behaviors that may be termed unstable and these must be defined in order to determine the most suitable type of machine. Beyond the shield itself, the cutterhead and the mucking system design are critical in successfully traversing difficult geology. In any but the shortest tunnels, variations in the geological conditions and the requirement of an acceptable advance rate can impose increasing degrees of sophistication in the machine design. In this paper we will review current designs of shielded type machines and their application, and discuss new developments which blend hard and soft ground tunneling technology. We will also indicate that in some conditions, although first impressions seem to favor a shielded machine, in fact an open gripper TBM may be the wisest choice.

Jan 1, 1991

By Daniele Martinelli, Rodrigo Winderholler, Daniele Peila

"This paper presents a technical description of an experimental procedure developed for the geotechnical characterization of granular soils conditioned for EPB tunneling using a modified direct shear box. As the main concerning parameters of the conditioned soil mass were their undrained properties, in order to preserve its pseudo-fluid characteristics, a watertight direct shear apparatus was constructed. A comparison between the results obtained under dry, saturated and conditioned conditions is presented. INTRODUCTION EPB shield machines have been used for tunneling excavation in many different types of soils thanks to the use of soil conditioning agents. These modify the properties of the soil into that of a plastic paste, thus permitting the homogeneous flow of the excavated soil from the tunnel face through the bulk chamber, the screw conveyor and finally the conveyor belt. Moreover this technique allows controlling the face pressure and its regulation in the bulk chamber, preventing water inflow when tunneling below the water table. Further advantages are a drop of the cutter head and screw conveyor torque and reduction of the friction between metallic parts and the soil, consequently reducing wear phenomena (Merritt & Mair, 2006; Vinai et al., 2007; Borio et al., 2010; Thewes & Budach, 2010; Herrenknecht et al., 2011; Barbero et al., 2012; Peila, 2014). Several studies have investigated the possibility of conditioning and the chemical materials to be used in different types of soils, mainly subdivided into three groups: cohesionless soils (sand and gravel), silts and clays, and rock masses. This various researches have set up several laboratory procedures for these achievements before and after soil conditioning, as stated in Thewes & Budach (2010) and Peila (2014) (for cohesionless soils), in Thewes & Burger (2005), Hollmann & Thewes (2013), Zumsteg et al.(2012) (for clay), in Peila et al. (2013) and Martinelli et al. (2015a) (for rock mass). Such tests should be simple to execute, reliable and easy to interpret at the in-situ excavation step. The reduction of shear strength is necessary in EPB operations, since it allows an effective transmission of the pressure from the material itself to the front. In some cases the slump is not sufficient to return a reliable result on the shear strength reduction, as in some cases some materials are behaving differently. Therefore this research is aimed to study this aspect more in detail, in order to show the effectiveness of the soil conditioning process on the material to be excavated."

Jan 1, 2016

By Ping Long, Peipei Liu, Xinlin Ren, Yunke Wang, Bin Yang, Jian Wu, Wenli Zhang

In this research, ICP-AES was used for determining ten impurity elements (Fe, Pb, Ca, Mg, Cu, Zn, Al, As, Sb, and Bi)in tin concentrate and smelting products, such as crude tin and slag. Samples were dissolved by hydrochloric acid and nitric acid. Determination conditions were investigated in detail. Influences of matrix and coexisting elements were eliminated by selecting proper analysis spectral lines. Under the optimum conditions, the correlation coefficient of cali- bration curves were higher than 0.999. The detection limits of these ten impurities were in the range between 0.0009 to 0.0621 lg/ml. Relative standard deviation (RSD) values were lower than 6.0%, and the recoveries of standard addition were between 85 and 109%. The proposed method was demonstrated to be reliable by comparingwithstandardanalysismethodsandcertifiedvaluesofstandardsample. It could be applied for determining impurity elements in tin concentrate and smelting products successfully.

Mar 1, 2017

By Gong-yi Guo, Yu-li Chen

"A partially-stabilized zirconia powder was prepared by metalorganic precipitation process from technical-grade zirconium oxychloride and the effluent of an acrylic acid plant. The effluent contained low molecular weight carboxylic acids, i. e., acrylic acid and acetic acid. The· developed process is based on the selective precipitation of acrylic acid at suitable pH values by the addition of zirconium oxychloride to the effluent. The resulting precipitate is a precursor that can yield a pure, ultrafine, and partially-stabilized zirconia powder. The evolution of formation of the partially-stabilized zirconia in the present process was investigated using thermal analysis, infrared spectroscopy, and X-ray diffraction technique. Environmental, technological and cost advantages will make the present process feasible for manufacturing advanced zirconia ceramics.IntroductionIn recent years the superior mechanical, thermal, electrical and chemical properties of stabilized zirconia have become the focus of growing scientific and technological interest, and hence resulted in various structural and functional applications. The great potential of the material has given rise to numerous preparation approaches to obtain the material with the excellent properties; nevertheless, an extensive number of programmes are underway worldwide aimed at understanding and improving both the preparation and behavior of stabilized zirconia ultrafine powders. (1 – 8)."

Jan 1, 2000