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By Heinrich Ries

Fullers' earth is a clay-like substance, which has the property of decolorizing or clarifying oils. An ultimate chemical analysis shows it to differ from most ordinary clays in having usually a high percentage of combined water and a low amount of alumina. There is probably a large amount of hydrous silica present. Fullers' earth possesses little or no plasticity, and in order to work properly has to be ground very fine. A chemical analysis is of little value at present in determining its quality; only a practical test suffices. Up to about two years ago all of the fullers' earth used in this country was imported from England; but about that time deposits were discovered in Florida, "† and since then rumors of its occurrence have been coming from all parts of the country. Next to the Florida deposits of fullers' earth, those of South Dakota are the most extensive thus far discovered in this country. The earth was first discovered near Fairburn, Custer county, and other deposits have since been prospected at Argyle, Minnekahta and other localities. Fairburn.—One of the first deposits located and opened up is five miles southeast of Fairburn, Custer county. The mine is a mile from the Fremont, Elkhorn and Missouri Valley Railroad, and the section exposed shows, beginning at the top: Feet. Micaceous sandy clay,......... 6 Fullers' earth,..........9 Micaceous sandstone,......... The fullers' earth passes upwards into the sandy clay, but in its purer portions it is a yellowish, gritty clay, with a somewhat

Jan 1, 1898

By Ham. Y. M.

The corrosion behaviour of Al-B4C metal matrix composites immersed in 2500 ppm boron-containing H3B03, 0.5 M K2SO4, and 3.5% NaC1 solutions was investigated. Effects of B4C particle volume fraction on the corrosion behaviour of composites were studied using potentiodynamic polarization and electrochemical impedance spectroscopy techniques. Scanning electron microscopy was employed to study the surface morphology of the material before and after corrosion. Results show that all materials investigated are more corrosion resistant in 2500 ppm boron-containing H3B03 than in other solutions. No appreciable corrosion was observed in boric acid and sulfate solutions in contrast to an obvious pitting in NaC1 solution for both base alloy and composites. The preferential pitting sites are the interfaces of Al/Fe intermetallics for the base alloy, and the A1/B4C interfaces for the composites. Increasing the volume fraction of B4C particles in the composite decreases its corrosion resistance of Al-B4C composites.

Jan 1, 2011

By Andrew Allan

[Research conducted by the Bureau of Mines hrinq the last 5 years on the uce of machines for 7!naer:rolmrl ?.eve loym~nt in pi.t,c hlng anthracite beds l~a~ provide? data ?howin? that ?:;panrt of thc roof an9 str?eg of thes? oTen - jnqs requires almst half of' the PRS? workin? time. The possibilitie~ of i!rinz a mvable,. te1.ee*co@. c tpr? 3f ?tee1 ~h-!.oltl at the face in~tetcrl of conventional wood a*ti~yorts w?r? si:~q~eteil by engineers engaqad on the~ work If ~uch a shi~l8 COLI.~,~. be ~sve~.~yad, it tnillil man that face workera w~uld be provi8ed with mulrnu.m prot?ct+on from falls of' roof and ribs mi! the en- tire ehift could he I~W? Lo ~lro,J.~:ce cocl. Fermanent tim3er coald be p'l.acnA behind the shielR independently of the 'face work as the face advanced.]

Jan 1, 1953

By Maurice Magee

The Ducktown ore deposits have been known, explored, and mined for 120 years. Eight massive sulfide ore bodies occur in highly folded and metamorphosed graywacke, graywacke conglomerate, mica schist, chloritegarnet schist, and staurolite schist of Precambrian age. The ore deposits are tabular bodies that have been extensively folded, generally conform to the enclosing rocks, but show local complex differences. The ore deposits, ranging in size from 250,000 tons to over 20 million tons, are composed principally of the minerals pyrrhotite, pyrite, chalcopyrite, sphalerite, and magnetite. Gangue minerals are quartz, calcite, actinolite, tremolite, hornblende, garnet, and masses of schistose wall- rock. Three fault systems are present that have influenced ore control and ore body configuration. Hydrothermal effects are evident in wall-rock alteration. Evidence of retrograde metamorphism is extensive in the wall and ore associated rock. Preliminary isotopic age dates have indicated four possible metamorphic events during the Paleozoic Era. Ore genesis is considered to be hydrothermal replacement of receptive beds, predominantly highly calcareous zones, quartzitic zones, and brecciated shear zones. Ore deposition is thought to have occurred during the Devonian Period, with later mobilization and recrystallization of the ore and gangue during Middle and Late Paleozoic times.

Jan 1, 1968

By J J. Hanhiniemi, M S. Powell

A ‘Variable Blend and Rates’ model is developed for SAG mills which extends upon the JKSimMet® Variable Rates Model. Similarly, a ‘Variable Blend Residence Constrained Perfect Mixing’ Ball Mill model is also introduced, also extending upon the existing JKSimMet® model. These models are used in conjunction with JKSimMet® while employing external technical programs. The technical model is then used to inform an economic model described elsewhere in Hanhiniemi and Powell (2022), which calculate operating and unit costs based on operating conditions, design, and ore characterisation. The SAG and ball mill models include constraints beyond those in the JKSimMet® models. The SAG model constraints include Size Specific Energy (SSE) verification, charge weight limit, and assessment of the impact of media to ore composition in the charge using the SAG Charge SSE Model developed in this paper. The ball mill model includes residence time, volumetric capacity, and SSE verification constraints. These models are applied to Cortez Gold Mine in the processing of two very different ore types and their blends; ‘Horse Canyon’ which is softer in coarser sizes and competent is fine sizes, and ‘Wenban’ which is competent at coarser sizes but softer in fine sizes than Horse Canyon. Horse Canyon also has a finer run-of-mine size distribution then Wenban. The application of the model at this site included undertaking five surveys at varying blends. The behaviours of the blends and individual components is then studied in the SABC circuit. A nonlinearity is observed with throughputs increasing with blending. The newly developed modelling approach captures these responses. Controlled blending based on ore competence-by-size and size distribution was implemented by the site, which then realised significant improvements in throughput without any capital cost (Ntiamoah et al, 2020). The modelling developed in this paper is then compared to existing practice, and the new method was found to provide improved fidelity and utility. A three-dimensional surface is then developed using the model describing the SAG mill throughput capacity at varying conditions (speed-filling) versus varying blend. The change in throughput as a function of only the changing charge composition is presented. The result is nonlinear, and explanations are provided to describe this behaviour.

Aug 24, 2022

By Gerrit V. R. Goodman

Future coal mining systems will be able to cut from crosscut to crosscut where advances could exceed 100 ft. However, limitations arise when ventilating such mining systems. In deep advance mining, there would be no workers at the face to advance ventilation tubing or curtain manually. Traditional methods also provide no means for maintaining face ventilation after the miner backs away from the face. U.S. Bureau of Mines research is studying means to provide effective ventilation at cut depths beyond the current limit of 4D ft. Several innovative ventilation schemes are currently being considered. One such method is the use of a jet fan to ventilate a deep cut. A jet fan is simply a freestanding fan using little or no ducting to direct the ventilation flow. Jet fan testing in a 90-ft entry revealed that higher exit velocities and greater penetration depth occurred when various configurations were used to confine and direct the air flow. Additional testing also indicated that 2,200 cfm of fresh air was delivered to the face? 90 ft distant when a check curtain was used to limit entrainment around the fan. Without this curtain, this quantity dropped to only 1,000 cfm. This testing indicated that a jet fan was capable of providing ventilation to a distant face area. It also highlighted potential problems, such as recirculation at the fan and reentrainment in the jet flow. Despite these potential problems, jet fans may be adequate for ventilating cuts exceeding 4D ft.

Jan 1, 2010

By Orlando Oliveros

The Los Bronces Mine and Concentrator, one of the three operating units of Compania Minera Disputada de Las Condes S.A. (an Exxon Minerals Co. affiliate), is located in the high Andes of East-Central Chile approximately 70 kilometers northeast of Santiago at an elevation of 3,650 meters above sea level. (Figure 1). Santiago, the capital city of Chile, is located at an elevation of about 500 meters above sea level and enjoys a very mild climate, similar to some areas of California. At the mine site, however, extremely heavy winter conditions prevail occasionally, with very heavy snow and the resulting snow avalanches endangering installations and people. At the same time, ideal skiing conditions are found at the nearby ski resort of Portillo and Farellones. Mount Aconcagua, the highest mountain in the western hemisphere is only about 55 kilometers further to the northeast of the Los Bronces mine.

Jan 1, 1983

By A. Boehm

Mineral selective flash roasting (Steiner process) in oxidizing atmosphere was tested successfully for the efficient low intensity magnetic separation of siderite from ankerite and other gangue minerals within the ore of the Steirische Erzberg, Austria. The calcium, magnesium and manganese containing siderite turns selectively into a ferromagnetic oxide phase while ankerite remains paramagnetic. The expulsion of CO2 increases the volume specific surface depending on the selected temperature. Unlike pure iron oxides absorbing SO2 below 530°C, the calcined siderite (enriched in the magnetic product of the Steiner process) acts as a sorbent for SO2 between 500 and 820°C. The effect was studied by thermogravimetric analysis and particle bed tests complemented with neutron thermo diffractometry (D20/ ILL). The energy input was simulated with the help of a tube furnace. The composition of the artificial combustion gas permeating the bed was close to that measured in pilot scale tests (6 % CO2, 12 % O2, 700 vpm SO2). The evaluation of data relating the SO2 variation in the off gas monitored by electrochemical cells to the actual phase composition revealed an intermediate ferrite phase as absorber. During the rapid decomposition in oxidizing atmosphere starting at 500°C the occurring siderite alters to a (CaO, MgO, MnO)Fe2O3 ferrite as an intermediate phase accompanied with sudden SO2 absorption. SO2 disintegrates the ferrite structure forming MgSO4 and MnSO4, taking Fe2O3 as a catalyst. Ankerite (enriched in the non magnetics of the Steiner process) starts to absorb at temperatures above 1000°C forming gypsum. The findings support the SO2 controlled operation of the Steiner process by ?autodesulfurisation?. It explains aspects of the SO2 implementation reactions within off gas recycling in Austrian sinterstrands. Keywords: magnetising flash roasting, neutron thermo diffractometry, SO2 absorption, siderite, ankerite

Sep 1, 2012

By Harold J. Schock

This paper describes an experimental method for the monitoring of diesel-generated exhaust gas pollutants in a dead-ended drift for the purpose of assessing the effect of control approaches. Experiments were conducted to determine the relative merits of these ventilation configurations: no auxiliary ventilation, induction ventilation at the entrance to the drift, and ventilation of the dead-ended drift with positive displacement tubing. The drift used in this experimental work was approximately 105 ft. (32.0 mf long and slightly downsloping, with an average height and width of 8 ft. (2.4 m) and 28 ft. (8.5 m1 , respectively. The data were gathered for assessing these ventilation methods and for gathering data to support a computer model of the dispersion and mixing processes. For this drift, it was found that ventilation with positive displacement tubing provided the best removal of diesel-generated pollutants. Induction ventilation appeared to be the least effective of the three methods examined. A comparison was also made between personal monitoring and area monitoring. Results of this analysis showed that in regions of high concentration gradients, it was not possible to get good agreement between point sampling and personal monitoring. In well-mixed areas, good agreement between the two methods of monitoring was obtained.

Jan 1, 1980

By Andrea Pedroza da Rocha Santos

Neste trabalho, amostras de aço Lean Duplex UNS S32304 foram submetidas à temperatura de 800°C em um forno acoplado a um difratômetro de raios-x durante intervalos de tempo de 30, 60 e 90 minutos. Com o objetivo de analisar em tempo real a transformação das fases constituintes, foram realizadas várias varreduras insitu durante os diferentes tempos de permanência em 800°C deste material. Assim, observou-se a formação da fase sigma neste aço, tanto nos contornos de grão da ferrita como nas interfaces ferrita/austenita. Os valores de fase sigma obtidos para cada tempo de exposição foram calculados através do método de Rietveld sobre cada difratograma obtido e variaram de 11% a 17%. Notou-se que a fase sigma exibiu crescimento contínuo até 60 minutos e variação após este período. Todavia, observou-se que a formação de fase sigma a 800°C ocorre de forma significativa neste material após 30 minutos de aquecimento, o que pode comprometer as propriedades do mesmo.

Aug 16, 2017

By Tzung-mow Yao, S Ki, J Word, J Vinson

Properly designed evapotranspirative (ET) cover systems can greatly reduce the amount of infiltration and groundwater recharge (deep percolation) into potential acid generating mine waste. In arid and semi-arid environments, infrequent precipitation, low measurable subsurface fluxes, spatial variability within mine waste and cover material, and evapotranspiration from below the cover system create challenges to monitoring moisture flux in these systems. Sloped ET single-layer (monolayer) cover depths and a variety of reclamation treatments are being studied at a copper tailing impoundment in Arizona, USA. To monitor the performance of different ET cover systems in response to precipitation patterns, four different test plots consisting of two different cover depths and two different vegetation densities were instrumented with heat dissipation sensor nests. The sensors measure the soil water pressure potential and allow hydraulic gradients to be determined within and below the cover systems to depths of 180 cm. Three replicate sensor nests were installed in each test plot to account for variability in materials and test plot treatments. Data collection occurs twice daily and is ongoing. Weather during the 26-month monitoring period was characterised by two months of greater than normal precipitation followed by nine months of normal precipitation and 15 months of abnormally dry conditions. Monitoring data indicate that deep percolation occurs in response to periods of extended precipitation, however, drying was observed to depths of six feet below the surface in all test plots. Using conservative assumptions regarding tailing hydraulic properties, one-dimensional downward flux predictions based on the monitoring data indicate very low (Additional long-term monitoring and installation of deeper and replicate monitoring sensors into tailings without cover systems are recommended to evaluate the long-term ET cover system performance and develop a better understanding of deep percolation rates at the sites.

Jan 1, 2003

By Chang Wei, Zhigan Deng, Minting Li, Cunxiong Li, Gang Fan, Xingbin Li

Molybdenum and nickel in black shale ore exists as amorphous sulfides which has highly active, and easily oxide to sulfuric acid and sulfate at low temperature in the presence of excess oxygen. Take advantage of the characteristic to leach molybdenum and nickel from black shale. Oxidation, conversion and dissolution behavior of amorphous colloidal molybdenum and nickel sulfide in pressure leaching process was studied. The effects of stirring speed, temperature, concentration of sulphuric acid, oxygen process and mineral granularity on molybdenum and nickel leaching were investigated. The results showed that dissolution rate increased with increasing temperature and stirring speed, but decreased with increasing concentration of sulphuric acid. And dissolution of molybdenum and nickel from ore only need oxygen without any other reagent.

Mar 1, 2017

The Rio Tinto Iron Ore group currently estimates grade attributes for mineral resources using ordinary kriging (OK). OK produces a smoothed globally unbiased estimate, but does not capture local variability, which can have significant impact on mine planning and scheduling. The dimensions and the multivariate nature of iron ore deposits make point simulations of whole deposits impractical. With a direct block simulation method the size and speed limitations of point simulations can potentially be overcome, resulting in a viable method for capturing local variability and for providing risk measures into the mine plan and schedules. Some iron ore deposits are highly folded (post mineralisation) and require preprocessing using an unfolding algorithm to properly define the continuity parameters and directions of anisotropy before simulation can proceed. Block co-simulation proceeds in unfolded space and since mine planning require a block-model with regular block-sizes; a regular block-model is unfolded first. This paper discusses a block co-simulation approach that can be used to simulate the irregular blocks resulting from the unfolding process. A section of an iron ore deposit is used for testing the block co-simulation algorithm and the simulation results are compared against the Isatis direct block simulation method. Available blasthole data is also used to validate the behaviour of the block co-simulation algorithm.

Sep 26, 2011

By Dinesh P. Amalnerkar, Nagegownivari Munirathnam, Tirthalli Prakash, Katia Vutova, Vania Vassileva, Veliko Donchev

"A time-dependent model for electron beam melting and refining (EBMR) of different metals and alloys is developed. The model is 3D axi-symmetrical and an adapted numerical scheme of Pismen-Rekftord type is applied. The developed computer program computes the thermal fields in the metal ingots during EBMR process as well as the dynamics of the thermal streams and the geometry of the molten metal pools. Calculated results for different regimes of EBMR of titanium are obtained and discussed in the paper. Experiments are performed and impurities' concentration data are presented. Simulation results are compared with experimental data and are used for optimization of the EBMR process in the case of Ti.IntroductionElectron beam melting and refining (EBMR) has an important role in the special electrometallurgy[ 1-6] and it is approved for obtaining of pure titanium [7]. EBMR of metals and alloys is being recognized as a competitive and even the single method for obtaining new materials for all areas of human activity.The principal scheme of the EBMR drip process is shown in Fig.1. A thin layer of molten metal is formed on the front part of the feeding rod during the e-beam processing and generated droplets fall into the molten pool in the crucible where the ingot is formed. The refining is mainly realized at the boundary liquid metal - vacuum. There are three zones in EBMR (Fig.1) - on the front part of the feeding rod (zone I in Fig.1 ), on the surface of the generated droplets (zone II in Fig.1) and the surface of the molten pool in the water-cooled copper crucible (zone III in Fig.1)."

Jan 1, 2013

By D. K. Sengupta

Increased recycling of waste paper has been emphasized in recent years in both the USA and Canada for environmental and economic reasons. Removal of ink particles from the waste paper pulp is therefore necessary. One of the most promising methods for ink removal is froth flotation. Our study investigated the feasibility of a simplified flotation scheme which showed that about 90-92% ink removal can be achieved while 95-97% ink removal is achievable if a hydrophobic polymer is used ahead of flotation. The clean paper pulp recovery was over 90%. The effects of pulping pH, flotation pH, and concentrations of flotation and polymeric reagents are discussed in the paper.

Jan 1, 1993

By Marcos Natan da Silva Lima

O presente estudo tem como objetivo avaliar a resistência à corrosão de dois aços alto teor de Manganês com relação à liga 9% Níquel em solução eletrólito 0,001M de NaCl. Para esta pesquisa foram utilizados dois aços com teores de Manganês de 22%, 27% e uma liga 9% Níquel que é amplamente utilizada na indústria petroquímica. Os ensaios realizados para comparação da resistência à corrosão foram o monitoramento do potencial de circuito aberto (OCP) e polarização linear anódica. Foi escolhida a solução de NaCl pela presença da maioria dos tanques de armazenamento e transporte de gás natural se localizarem próximos à região marítima portuária. Foram utilizadas as técnicas de Microscopia Eletrônica de Varredura (MEV), Microscopia óptica e Espectroscopia de Energia Dispersiva de Raios-X (EDS) para a caracterização dos produtos de corrosão. Os resultados obtidos mostraram que os aços alto Manganês apresentaram valores similares de resistência à corrosão, mas ainda inferiores em relação ao aço 9% Níquel.

Oct 30, 2017

By Leslie Gertsch

Outline First progress report ? ?Introduction ?Non-terrestrial mining ?Near-term targets ?Stages of mining ?Study procedure Capabilities needed for non-terrestrial mining ?Mining methods ?Mining unit operations ?Typical surface mine operations sequence ?Results to date General effects of gravity ?On fragmentation ?On excavation ?On transport ?Conclusions / Recommendations

May 1, 2013

By G. S. S. Raman, M. S. Klima

The effects of pressure and cake thickness were studied using a split-plot design for pressure filtration of a fine refuse slurry obtained from a bituminous coal preparation facility. Pressure filtration offers the potential to significantly reduce the moisture content of the fine refuse stream with the addition of little to no flocculants, thereby minimizing the volume of refuse stored in impoundments and providing a recycle water stream for use within the plant. Experimental results showed that the final cake moisture decreased with increase in pressure and decrease in cake thickness. In addition, specific cake resistances calculated for the various tests indicated an increasing trend with increasing pressure and decreasing cake thickness. With increase in cake thickness, an increase in cake moisture and the weight of solids deposited in the cake was observed. An ANOVA analysis indicated that both cake thickness and pressure significantly affected the cake moisture, while only cake thickness statistically influenced the weight of solids in the cake. A regression model was developed with an R2 value of about 0.99 to relate cake thickness, the single largest statistically significant factor, with the weight of solids in the cake. Filter capacities were calculated in terms of the solids deposited per unit time based on a product specification of 25 percent cake moisture, and it was observed that the thinnest cake had the highest filter capacity.

By W. J. Li, L. Kong, G. L. Li, X. M. Xi, J. Qiu

"A novel hydrothermal method was applied to prepare the precursor of LiMn2O4 using pre-treated electrolytic manganese dioxide (EMD) and lithium hydroxide as the main raw materials. The precursor was subjected to heat treatment between 400 and 900ºC to obtain spinel Li1.05Mn1.95O4 and Li1.035Co0.035Mn1.930O4 positive materials for lithium ion batteries. The structure and morphology of the obtained powder materials were studied in detail by means of X-ray diffraction (XRD) and scanning electron microscope (SEM). It is found that the precursor has an amorphous structure and a high reactivity, which is easily transferred to spinel structure during heat treatment, obtaining a positive material with an uniform structure and good performances. The XRD patterns reveal that single phase spinel Li1.05Mn1.95O4 can be obtained from the precursor after heat treatment at 600°C in air. The final Li-rich Li1.05Mn1.95O4 product obtained showed a well-defined stable spinel structure and distinctive crystal faces with particle size between 200 and 300 nm. The as-prepared Co-doped spinel sample exhibited a excellent electrochemical performance with an initial discharge capacity of 113.0 mAh/g and 93.8% of its original value was retained after 100 charge-discharge cycling at 0.5 C.INTRODUCTIONThe increasing demand for portable electronic devices and hybrid or full electric vehicles is driving the development of cheap, efficient, compact lightweight and environmental friendly rechargeable batteries systems (Chung et al., 2002; Scrosati, 1995). Lithium ion secondary batteries have satisfied this demand to a greater degree than other battery systems. The cathode material plays a critical role in the performance of Li-ion batteries. The high cost and toxicity of cobalt compounds for the cathode material of LiCoO2 has prompted a search for alternative materials. LiMn2O4-based spinels offer a potentially attractive alternative to LiCoO2, due to its abundance, low price, ease of preparation, environmentally friendly characteristics, better thermal stability, and its effortless recycling (Tarascon et al., 1991; Yabuuchi and Ohzuku, 2003; Amatucci et al., 1999; Tsai et al., 2003). Some achievements have been created to meet the requirements (Guo et al., 2010; Kang et al., 2005; Park et al., 2008; Takahashi et al., 2006; Lee et al., 2001; Yoshio et al., 2001; Arumugam et al., 2008). However, the largest obstacle encountered in the practical applications of LiMn2O4 is its fast capacity fading during long term cycling, which is due to Jahn-Teller distortion of the [MnO6] framework, the electrolyte decomposition at high potentials and manganese dissolution into the electrolyte (Fey et al., 2003). The electrochemical performance of LiMn2O4 is also strongly dependent on its morphological properties, such as crystallinity, phase purity, surface area, grain shape and particle size distribution, etc. All these morphological properties are closely related to the material synthetic routines and heat treatment processes (Huang et al., 2000; Myung et al., 2000; Takada et al., 1998)."

Jan 1, 2012

By I. D. Reznik

The flowsheets of converter matte production from sulphide copper - nickel and oxide nickel ores on Severonickel and Yuzhuralnickel integrated ,;corks are given. The cobalt behaviour in electrosmelting and autogenous ore smelting, converting and converter slag cleaning is observed. A list of acticles published in the 80 th is given.

Jan 1, 1993