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Jan 1, 1941

By J. B. Cunningham

Lithium in the form of metal, salts, and alloys is particularly important because of increasing industrial uses resulting partly from wartime developments. Lithium carbonate and lithium strontium nitrate, which impart a brilliant red color to a flame, are used in pyrotechnics. Lithium chloride and fluoride are used in fluxes for welding aluminum to dissolve the oxide coating on the aluminum and prevent oxidation of the molten metal. Lithium carbonate is used in ceramics in raw alkaline glazes because of its unusual fluxing properties. The use of 9 to 12 percent lithium carbonate permits a marked increase in the amounts of alumina, calcium, and silica that may be Used and results in a more stable glaze with sufficient alkalinity to produce vivid copper blues and other typically alkaline colors. Lithium stearate is used as a grease in airplane engines because of its ability to withstand wide changes in temperature. In view of its great affinity for nitrogen, hydrogen, oxygen, sulfur, phosphorus, carbon, and silicon, lithium has an excellent scavenging action on molten metals. It forms stable nonmetallic compounds of low specific gravity or gases that are eliminated at pouring temperatures. Lithium is generally added to the melt in the form of a lithium-calcium alloy consisting of 50 percent of each ingredient or as an alloy of 98 percent copper and 2 percent lithium. The lithium-calcium alloy added to cast iron before pouring, acts as a scavenger and increases the fluidity of the melt. This alloy also is said to increase the corrosion-resistant properties of stainless steel alloys and to improve their polishing qualities.

Jan 1, 1948

By Martin Smirlock

A novel instrumentation system has been developed which enables simple, quick, and accurate measurement of vehicular dynamics within low speed ranges. The system, consisting of a microwave transceiver and microprocessor data acquisition and reduction system, measures the deceleration dynamics of low-speed mining and construction equipment. It makes the basic measurement, calculates key parameters such as average deceleration, initial velocity, stopping distance, and brake system delay time, and produces autoscaled graphs of velocity, acceleration, and displacement versus time.

Jan 1, 1981

The objective of this condensed handbook is to provide the inspector with guidance for recognizing hazards from inhalation contaminants in above ground work areas of underground and surface coal mining and processing facilities and evaluating these hazards by collecting samples or making field determinations and interpreting the analytical results. It will be carried with the inspectors during their surveys. The complete handbook should be left in their offices except for Appendix II which lists the compositions of products found in previous surveys. There are several portions of the condensed handbook which should prove most useful to the inspectors. The names and locations of these portions are listed below: Procedure for an Industrial Hygiene Survey (Page 2-1) Survey Check List (Page 2-3) Rules for Determining if Sampling is Required (Page 2-2) List of Most Frequently Encountered Contaminants (Page 2-5) List of Candidate Contaminants and their Sampling Conditions (Page 2-A) Interpretation of Results (Page 3-8) For obtaining information not available from the above mentioned portions of the handbook, the inspector is directed to the Table of Contents, and the Glossary of Terms (Appendix I).

Jan 1, 1975

By James C. Barker

The U. S. Bureau of Mines made a reconnaissance In the western Crazy Mountains for cobalt and associated metals as part of the Alaska-wide critical and strategic metals program. The area, located about 75 miles north of Fairbanks in central Alaska, is underlain by complexly faulted, predominantly clastic sedimentary rocks bordering the Tintina Fault system. Above background metal concentrations were found to occur in altered fault zones, tectonic breccias, soils, and ground water seeps and precipitates that either cut or are derived from the faulted clastic sedimentary rocks. Up to 0.115 pct cobalt and more than 2.0 pct zinc were detected in soil samples. Spring precipitates contained up to 1.3 pct zinc, 0.037 pct tungsten, and other metals. Some localities lacked cobalt but contained anomalous amounts of copper, lead, zinc, silver, and other metals. No outcropping of primary metallic minerals was located because of Colluvium and vegetation cover and extensive deep leaching. Therefore, whether the metal values encountered are due to primary deposits with economic development potential or are the results of concentration by ground water from low-grade sources is unknown. The presence of cobalt, nickel and zinc, and the identification of minor tin and tungsten indicate that further investigation is warranted.

Jan 1, 1983

By Susumu Uchiyama

This machine was manufactured for excavation of the Roppongi station of the Tokyo Metro Line 12. This machine can excavate both the platform and the rail track at the same time in locations where the traffic is congested and has following features: A multi-centered TBM of the size of 7.06(H) x 13.18(W) m The world first H&V TBM, with right and left machine parts articulated vertically and separately for position control A large erector for simultaneous erection of column and central segments of special shape to construct a highly reliable tunnel This paper reports the design concept, construction, and work record.

Jan 1, 1999

By Michael Gauna

An evaluation and analysis of a coal pillar bump in a West Virginia mine indicated that the pillar bump occurred because of the unique combination of controlling factors. The pillar?s development stability factor of 2.6, based on Mark-Bieniawski strength and tributary loading, would typically indicate an adequate pillar size for long-term main entries. A combination of multiple-seam mining geometry and geological conditions resulted in stress concentration leading to the coal pillar bump. No high extraction mining had been performed in the area and the overlying works appeared to have adequate stability factors. However, it was interpreted that long-term flooding had softened the overlying pillar system and rendered all but the largest pillars ineffective. Contributing factors include large overlying pillars transmitting stress through the approximately 60 ft of interburden and the failed pillar?s location at a transition in the immediate roof from shale to hard, massive sandstone. Other contributing factors include sandstone channeling forcing the development section to mine the pillar smaller than surrounding pillars in an attempt to avoid the channel, the relatively high overburden of 1,100 ft, and the pillar?s position in the bottom of a trough within the coal horizon. Pillars subjected to similar conditions on the other side of the section did not fail where the roof was composed of shale, even though the roof exhibited evidence of high stress concentration. An analysis was undertaken to determine appropriate pillar size for future mining. The conditions were evaluated by investigating mine historical conditions, assessing pillar bearing pressures, and using Lamodel 2D coupled with traditional Mark-Bieniawski pillar strength and tributary area loading stability factors to determine the stress levels for the pillar. Recommendations for future pillar sizes were based on the critical load bearing capacity identified by the analysis. To date, no further pillar bumps have occurred.

Jan 1, 2008

By M. E. Rossi

All large-scale applications of conditional simulations intend to benefit from the ‘correct’ (or’ accurate’) characterization of uncertainty, adequately describing the variability observed from the data and its impact on the final objective. This paper discusses a number of relevant issues that highlight the extent to which, in reality, a model of uncertainty is dependent on the random function model chosen. Often in the presence of large number of conditioning data most available random function models will provide similar models of uncertainty. When conditioning is scarce, the resulting models of uncertainty will vary more widely, since the final output will depend mostly on the underlying assumptions of the model chosen. The application described in this paper is taken from a large porphyry Cu operation in northern Chile, and it demonstrates the impact of several variables on the resulting models of uncertainty. In particular, some of the decisions involved include the number of conditioning data and the underlying Random Function model used (Gaussian or indicator-based). Also, implementation-specific parameters must be decided upon, such as grid size used, random number generator, simple or ordinary kriging, multiple-grid simulation, and simulation of irregular three-dimensional bodies (as opposed to regular grids). Some practical guidelines are proposed to deal with these decisions.

Jan 1, 2003

In a gravity separation device, particle shape, size and density all play a role. The combination of these determines where each individual particle reports to in the viscous fluid, where particle crowding (solids to water ratio) also plays a role. To understand the performance of gravity separation devices in the heavy mineral industry, these particle characteristics need to be measured. There are various challenges in analysing particle density and particle size simultaneously for the purpose of quantifying gravity separator performance, not to mention particle shape. These analytical challenges include the high cost of high-density sink-float fractionation, toxicity of high-density sink-float media, inability of sink-float media to fractionate at densities greater than 4.0 g/cm3, and the time-intensive nature of these fractionations. The use of the detailed particle-by-particle output from Qemscan® particle mineral analyses (PMA) as a fast and cost-effective alternative is evaluated. The size and density outputs from the Qemscan® were employed to characterize the performance of a heavy mineral spiral concentrator as an example. Critical analytical requirements are to be addressed before the Qemscan® output data can be utilized. Keywords Gravity separator, performance, heavy minerals, Qemscan® particle mineral analysis

Jan 1, 2011

To alleviate the hazard to personnel and danger to equipment caused by fires on large, mobile vehicles. The Approach: A system which automatically senses a fire at its early stage of development, warns the driver of the danger, and activates fire extinguishers in the zone of combustion, How It Works: The automatic fire protection system utilizes both thermal and optical sensors to detect the heat or light given off by a fire in the area of concern (Fig. 1). The system warns the driver of the hazard and then automatically extinguishes the fire with pressurized S-C class powder. The system can also be activated manually from the operator's cab or from ground level. Further, the automatic sequencing of the system can be manually overridden by the driver if he determines that the fire sensors have malfunctioned to cause a false alarm.

Jan 1, 1974

By J. C. Kerkering, S. M. Miller, P. C. McWilliams

Researchers at the U.S. Bureau of Mines investigated the use of close-range photogrammetry and subsequent stereo digitizing to obtain data from rock fracture roughness profiles. The photogrammetric process yielded results that were acceptable but somewhat inferior to those obtained by a mechanical profilometer. On the basis of this study, further pursuit of photogrammetry as a data collection method in mining is proposed. Fractal geometry was investigated as a means of measuring the roughness of rock fracture profiles. Four fractal algorithms were used: divider method, modified divider method, box method, and spectral method. A comparison of the methods gave ambiguous results. Brown's modified divider method provided the best means of obtaining the fractal dimension. Shear strength estimates were obtained using the parameters of the modified divider method and Myers' Z, measure. Because of differences in results when comparing the different ways of obtaining the fractal dimension, future users of fractals in studies of rock fractures are advised to cross-check their results carefully.

Jan 1, 1993

By Phillip M. Busch

VANADIUM was discovered in 1801 by Andres Manuel del Rio, a professor of mineralogy at the School of Mines in Mexico City. Del Rio called the new element erythronium. Later, he decided that this was not a new element but a form of chromium. Not until 1831 did Nils G. Sefström, a Swedish chemist, positively determine that the metal was a new element which he named vanadium, after Vanadis, the Scandanavian goddess of beauty. From 1831 to the 1860's and 1870's, the comparative scarcity and high cost of vanadium restricted its commercial use. Shortly after 1870, more information was obtained on the physical and chemical properties of the element. Thereafter, research on vanadium has dealt largely with its use as an alloying element in steel and nonferrous metals. Vanadium is a widely distributed element in the earth's crust. It is more abundant than many metals but is disseminated in small quantities throughout a great variety of rocks. Relatively few deposits have contained ore of a grade suitable to warrant development for vanadium alone. It is produced in conjunction with uranium, iron, titanium, aluminum, and lead-zinc ores.

Jan 1, 1961

By Ian Misich

A research programme has been undertaken to evaluate and predict the effect of total extraction of coal by underground methods on the superimposed strata, aquifer systems and ground surface in the Collie Basin. Western Australia. The research work has integrated comprehensive field monitoring of surface and subsurface subsidence with empirical, analytical and physical modelling in an effort to develop an effective predictive tool which can be used in all mining scenarios. Early results indicate that although each method has certain limitations, this approach has enabled the researchers to develop a very good understanding of the subsidence mechanisms from the mine panel through to the surface in the weak, water saturated sediments in the Collie Basin. Given that both subsurface and surface subsidence characteristics have tied in well, greater confidence can be held for predictions made by representative models.

Jan 1, 1993

By G J. Corbett, T M. Leach

Approximately 42 t of mercury were produced from Puhipuhi from the late nineteenth century until the end of World War II, with no significant gold or silver production. Sinter, eruption breccias and veins, mined for mercury at Puhipuhi and essentially barren of gold, are inferred in many geological models to represent the surficial levels of adularia-sericite style low sulfidation gold-silver systems. These systems may contain economic gold-silver mineralisation at depth. Conceptual geological models have been employed at Puhipuhi in the search for buried gold mineralisation. Homestake Mining utilised a McLaughlin model for exploration from 1982 to 1987, targeting mainly the vicinity of the sinter deposits. From 1987 to 1989 BHP sought deeper structurally controlled gold mineralisation within the basement greywackes, utilising models derived from studies of Round Mountain, USA and Hishikari, Japan. Macraes Mining Company Limited have accessed the previous work and applied a conceptual geological which invokes a north-south structural control for the emplacement of high-level felsic intrusions at depth. Dextral movement on these structures associated with oblique convergence facilitated the formation of a pull-apart basin in which lacustrine sediments overlie basement greywackes and are in tum overlain by Pliocene basalts. Continued activation of the NS structures created a series of inferred NE-trending dilational structures, which are targeted as fluid upflow centres for the surficial outflows. Upflows occur as eruption breccias (e.g., Plumduff) and outflow as silica sinters (eg Mt Mitchell, Williams) which are also partly obscured by the basalt cover. Argillic alteration and mercury mineralisation occur at elevated crustal levels (eg Puhipuhi mine). Modelling from structure and alteration zonations have targeted a fluid upflow in the vicinity of Bush Hill, which was not accessed by previous workers. This target was subsequently supported by surface geology and multi-element soil geochemistry.

Jan 1, 1997

By Surendra Kumar Biswal, Sachida Nanda Sahu, B. C. Meikap

The unutilized iron ore fines (IOF, − 10 mm, 45% to < 60% Fe(T)) left at various mine sites during blasting and processing are rich in goethetic-hematite associated with high clay and considered a potential iron ore resource. The variation of loss on ignition (LOI) from mines to mines is based on the goethite and clay mineral content. The clay containing below 45 μm is mostly brittle, causing beneficiation problems. The IOF has an LOI of 7.83%, with high silica (5.52%) and alumina (4.57%), and 57.17% of Fe(T) subjected to both conventional deep beneficiation (CDB) and magnetization roasting using high-ash non-coking coal to adopt the suitable upgradation process. The CDB and magnetization roasting concentrate has 62.61% and 67.58% Fe(T) with 64.69% and 85.19% yield, respectively. However, the presence of 6.40% LOI in CDB makes the ore challenging for pelletization. Characterization like X-ray diffraction(XRD), scanning electron microscope(SEM), and chemical analysis was used to assess the concentrate quality and potential industrial application.

Jun 4, 2022

By Wadaw Cybulski

The problem of coal dust explosions: Basic information about the explicability of coal dust: Main parameters of the explosibility of coal dust; Main parameters of the explosibility of coal dust; Limit explosibility of coal dust and its dependence upon the basic parameters: The effect of the initiator of the explosion-on-the explosibility of coal dust: The dependence of the course of an explosion upon the distribution of coal dust in the workings, upon the dimensions of the workings, the length of zones, the direction of the development of explosions and upon the content of firedamp in the air of the workings; Con-sequences of coal dust explosions; The ways of suppressing the danger of coal dust explosions; Stopping the developed coal dust explosions; The explosibility and explosions of lignite dust of xylite structure

Jan 1, 1975

By Arnulf Muan, Egil Aukrust

Activities of COO in the three solid solution series COO-MgO, COO-MnO, and COO-"FeO" have been determined at 1200°C by equilibrating oxide samples with a metal phase (cobalt or a Co-Fe alloy) in atmospheres of known oxygen activities. The systems COO-MgO and COO-MnO are ideal, within limits of experimental error, whereas the system COO-"FeO" shows a slight positive deviation from ideality at the temperature of this investigation. KNOWLEDGE of activities of oxide components in solid solutions is necessary for the calculation of the cation distribution among coexisting oxide phases in many important metallurgical, ceramic, and geochemical systems. Very few activity-composition curves are available for such systems at the present time. A start on the prodigious job of obtaining such data has been made by studies of solid solutions with simple sodium chloride type structure containing NiO or "FeO" as a component.1-3 The present paper describes similar studies for solid solutions with sodium chloride type structure containing COO as a component. For the systems COO-MgO and COO-MnO, the activity solid solution is determined by the equation Here po and are the oxygen activities of the gas phase in equilibrium with the phase assemblages metallic cobalt plus oxide solid solution, and metallic cobalt plus pure COO, respectively. In the system CoO-"Fe07&apos;, the metal phase is a Co-Fe alloy rather than pure cobalt. In this case the activity of COO in the oxide solid solution is calculated from the equation where a& is the activity of cobalt in the metal phase. Because the system Co-Fe is close to ideal4 and the metal phase appearing in the present work contains less iron than cobalt even at the lowest COO concentrations of the oxide phases used may be set equal to N . Hence, Eq. [2] becomes The value of Nc, can be estimated from the relative stabilities of the oxides COO (see below) and I) EXPERIMENTAL METHOD Two different but closely related procedures were used in the present investigation to determine the activity-composition curves. In one method, the oxide solid solutions were equilibrated against

Jan 1, 1963

By Robert Stefanko

The growing demand for energy during the post World War I and World War II periods has prompted underground coal production to increase rapidly. This has been met primarily by mine mechanization, resulting in the development and application of new mining machine types. Correspondingly, the total connected horsepower of each machine as well as the number employed has enlarged rapidly since 1950. (2,3,9,14,16,17) Electrical consumption for each mine has also grown. In the early years of mining electrical applications, only d-c power was utilized underground. Yet, d-c machine limitations were soon realized, and many a-c systems were substituted to permit economic and efficient utilization of a-c distribution and motors. Due to the attractive torque characteristics, ease of distribution and speed control, several traction applications have continued to be powered by d-c motors. The result has been the now prevalent use of mixed a-c/d-c mine power. However, augmented electrical power employment seems to have added to underground coal mining electrical accidents.

Jan 1, 1974

By J. R. Hart, V. C. Smith, V. P. Babarovich-Hansen, J. H. Schubert

"An introduction and case study of Mintek's latest generation of Milling Circuit controller, the MillStarTM with IES (Interpreting Expert System) is presented. This paper also describes as a case study its installation on a Southern African base metals concentrator plant which has demonstrated improved operation, greatly reduced variation in product quality, as well as increased capacity and availability of the circuit.In this case study, the MillStarTMw as installed along with several other enhancements, including hydrocyclone underflow monitoring, product particle size estimation and flotation circuit stabilisation. MillStarTM utilised the particle size measurement to control grind to within 2% of setpoint, all the while ensuring sump level control, density control as well as mill power optimisation. Mintek' s expertise in the modelling of tumbling mills allowed the development of a specialised optimising controller that ensured the mill was kept in the most efficient operating region.MillStarTM augments the automatic control with useful user interface features, such as on-line trends of any logged variables, historic data warehousing and retrieval and production summary reports.A novel feature that distinguishes the MillStarTMi s the IES (Interpreting Expert System). This is a feature of the software that works with the automatic control code to generate explanations for control actions made by the controller. Often complex control systems are mysterious in nature, reducing trust and eventually resulting in them being switched off. The IES method of exposing the heart of the controller has proved popular and is seen to have potential as a training tool. 314"

Jan 1, 2000

By Onur Kacar

A numerical approach has been implemented to assess the settlements of pile groups bearing in clay. A three-dimensional finite element program has been utilized to model a vertically loaded spread footing, a single pile and a pile group. The soil-pile interaction was modeled with elastoplastic soil and interface elements. The model has been calibrated using a full scale load test results of the spread footing. The load transfer between the pile cap and the piles was assessed and compared with the measured load transfer. The predicted settlements for the pile group were compared with the settlements measured in the load test. Two analytical methods were adopted to predict the pile group settlements and they were compared with the measured values. The group effect determined from the analysis and load tests was compared with the interaction factor approach. It was shown that three-dimensional finite element approach can be successfully utilized to assess the soil-structure interaction and hence the load transfer between the piles and pile cap. Also, it was shown that the interaction factors method and equivalent footing method work well in the working stress range, however they underpredict the settlements at larger loads. INTRODUCTION The settlement and stress distribution of pile groups have been traditionally estimated based on load test results of single piles and accounting for the group effect using various approaches. The most widely used approaches are group interaction factor method, equivalent footing method and equivalent pier method. These approximate solutions are used very commonly in practice as full-scale load tests on pile groups are very expensive and time consuming. These approximate solutions are also adopted in design guidelines such as AASHTO LRFD Bridge Design Guidelines (2014) and FHWA Design and Construction of Driven Pile Foundations (2016). In this paper, a full-scale foundation load tests performed by Nagai et al. (1961) and reported by Koizumi and Ito (1967) is modelled using a three-dimensional numerical method. The settlements and the stress distribution on foundations were then compared with the traditional equivalent footing method and interaction factor methods.

Jan 1, 2018