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By S. J. Aparo

Phosphate mining and beneficiation in the State of Florida are presently being carried on by 12 different mining companies with a total of 21 mining and flotation plant locations. Their combined production of both washer rock and flotation concentrate was approximately 28,000,000 long tons in 1968. This accounted for 70-72% of the total U. S. production and close to 30% of the world's output of this mineral. From this extensive activity in the Florida phosphate field, one basic flow sheet for beneficiation of the ore has developed over the years as the most commonly employed. In fact, all of these plants with the exception of two beneficiate Florida pebble phosphate using a basic operation as illustrated in Figure I. The two plants which differ from this general approach are not using raw matrix as feed. In one instance, +14 mesh pebble is ground in a rod mill to release free silica which is subsequently removed in a cationic froth flotation circuit using an amine acetate blend and kerosene. This technique generally results in a 4-7 BPL unit upgrading of the feed pebble. The other exception to the standard flow sheet illustrated in Figure I is an operation which is beneficiating tailing piles. In this case, the material is first subjected to cationic froth flotation in order to upgrade the feed to a point comparable to normal matrix. Thereafter, after, the phosphate is floated in an anionic rougher circuit followed by cationic flotation of the silica in a cleaner circuit.

Jan 1, 1969

By Peter Zhang, I. BERK TULU, Morgan M. Sears, Heather Dougherty, Ted Klemetti, DYKE MARK VAN, Gabriel S. Esterhuizen

Ground falls in longwall gateroad entries remain a concern in modern longwall operations. The gateroads are subject to changing horizontal and vertical ground stress induced by longwall extraction. These stress changes can result in failure of the strata around an entry leading to large deformations of the entry roof, floor and ribs. The gateroad support systems are required to control the failed strata while maintaining safe access to the longwall face and unimpeded ventilation. This paper presents research conducted to better understand the stability issues in gateroad excavations and to develop procedures for evaluating support and layout alternatives for longwall gateroads. Using the results of a field-monitoring program and numerical model analysis of case histories, a conceptual model of gateroad support needs was developed. The conceptual model formed the basis for developing a set of equations that can be used to estimate likely roof sag and support loading for given roof geology and longwall-induced loading conditions. The developed equations were used to compare predicted gateroad stability to field study results, showing satisfactory agreement. The calculation procedures are used to demonstrate their application in assessing support alternatives at a case study mine. It is concluded that the developed analysis procedures provide realistic assessments of likely ground stability and can be used to evaluate alternative gateroad support systems at operating longwall mines.

By Charles F. Stack

The A. P. Green Refractories Co. operates clay mines in ten states. Eight of these states have reclamation laws with which we have to comply and indications are that the U. S. Congress will pass a federal surface mining reclamation act in the near future. These regulations, in addition to the value of land in most areas, dictate that mining and reclamation be considered as a single operation. In many instances the land may be more valuable after properly planned mining and reclamation than before. Refractory clay, commonly called "fire clay" is defined as a siliceous clay rich in hydrous aluminum silicates, capable of withstanding high temperatures. It is deficient in iron, calcium, and alkalies and approaches kaolin on composition. Refractory clay is much more limited in occurrence and usage than common clay or shale. During 1971, common clays and shales were mined in 47 states with a total production of 45 million tons. Fire clay production was reported in 22 states with a total production of only slightly over 3 million tons.(1) Many of these producing areas are extremely limited in extent and production. Several are contained within a one or two county area. This reflects the unique geological conditions required for the formation or development of fire clay. The major fire clay producing areas in the United States are shown in Figure 1.

Jan 1, 1974

By P. L. De Bruyn

[According to the Young equation, SG = SL + Coso, the equilibrium contact angle depends on the values of the three interfacial tensions involved. A solute promotes wetting, i. e. a decrease of contact angle if it decreases.LG and/or YSL or if it increases SG. Dewetting, the important step in flotation is, promoted if the solute increases y and/or SL or decreases. Most solutes used for wetting or dewetting are, positively adsorbed at all interfaces involved and consequently according to the Gibbs equation lower the interfacial tensions. Wetting is therefore expected to occur if LG and SL are more affected by the solute than SG. Dewetting on the other, hand demands a greater decrease of SG than that of SL (and of LG). See P. L. de Bruyn, J. Th. G. Overbeek and B. Schuhmann, Jr., Mining Engineering (1954) P. 519.]

Jan 1, 1960

By Ulrich Benatzky

Rheinbraun AG, Germany, is the management company of the mining and raw materials division of RWE AG. Rheinbraun's core business and major functional area is opencast lignite mining in the Rhineland. The characteristic feature of opencast mining is continuous operation using bucket-wheel excavators, belt conveyors, and spreaders. The report gives a survey of the conveyor systems used. In addition to the general performance data of these belt conveyors, this report will deal in particular with major components, such as drive stations and individual mechanical components (e.g., conveyor belts, pulleys, gears, couplings, brakes, scrapers), as well as monitoring systems. Finally, an assessment of the conveyor systems, together with future developments, will be given.

Jan 1, 2000

By S. C. Sun

Very little information is available concerning the magnetic properties of minerals and only recently has there been any attempt to correlate magnetic susceptibility with varying chemical composition1. The work described here covers a study of the relationship and chemical composition of both the rutile and sphene types of titanium minerals. The relationship between the magnetic susceptibility of three selected mineral specimens and the applied field strength is also presented. Experimental: The equipment and procedures used in this in- vestigation for crushing and cleaning the mineral specimens and for determining the magnetic susceptibilities were the same as that employed by Spokes and Mitchell1. The particle size of-the measured specimens was limited to 270/325 mesh.

Jan 1, 1959

By William G. Freeman

As with most industrial minerals, barite is freight sensitive. This paper is given so that others might gain from the experience of barite companies in reducing their transportation costs. Some of the approaches used were unusual and others standard, but by perseverance considerable savings were realized.

Jan 1, 1973

By R. L. Miller

The potential for recovery of enriched uranium from spent nuclear fuel which has been consolidated into a nuclear waste form was explored in the studies reported here. The waste form of interest is iron-enriched basalt (IEB)--a silicate-based, fused-cast ceramic. IEB samples were prepared containing fuel assembly materials that simulate the core debris of Three Mile Island Unit II;1,2 the nominal composition of the consolidated waste form is given in Table 1. Ore Types The IEB samples, or man-made uranium ores (MMUO), are in two different mineralogical forms. Each MU0 was made by melting the constituent materials and holding at about 1500°C for 1 h. The MMUOs were then heat treated to control crystallization and crystal growth and then cooled to room temperature.

Jan 1, 1983

By William Gleason

"The times they are a changing, and, for the mining industry, the optimism is high. On Nov. 8, Donald Trump was elected as the 45th president of the United States, and the Republican Party won a majority of seats in the U.S. Senate and the House of Representatives, ushering in what many hope will be a positive change for the mining and extractive minerals industries.Trump has stated that one of his top priorities as president will be to increase spending on the nation’s infrastructure, which could help spark a boom for mining. He has also pledged to bring back coal jobs and reverse many of the environmental regulations that were put in place by the Obama administration. However, before the mining industry gets too far ahead of itself and plans for another Super Cycle, there are stark reminders that any work in the natural resources sector is complicated and challenging. On Dec. 4, the U.S. Army Corps of Engineers announced that it would not grant an easement that would allow the Dakota Access Pipeline to pass under a portion of the Missouri River in North Dakota. The proposed crossing of the oil pipeline is approximately a half a mile upstream from the Standing Rock Sioux’s Reservation, and for months, hundreds of protestors camped out at the site in an effort to halt the project, saying they feared how it would impact water supplies and sacred lands.Energy Transfer Partners, the company building the pipeline, said the pipeline is a $3.78-billion investment that will connect the Bakken and Three Forks production areas to major refining markets. The company signed voluntary easement agreements with landowners representing more than 85 percent of the properties along the four-state route but faced an organized protest from the Sioux Nation at Standing Rock. The protest gathered momentum and support through social and traditional media and became the focal point of global environmental and indigenous activism. The protestors claimed victory, at least temporarily, when the Corps of Engineers said it would look for alternative routes for the project. It’s a decision that could lead to a lengthy environmental review and one that has the potential to block the construction of the pipeline for months or even years."

Jan 1, 2017

By William Gleason

"The Colorado School of Mines has used the Edgar Mine in Idaho Springs as an experimental mine to teach students since 1921. Since the school acquired the former gold, silver, lead and zinc mine, countless students have received hands-on engineering lessons on their way to earning mining engineering degrees. On Dec. 14, the House Subcommittee on Energy and Mineral Resources held a historic field hearing about the future of mining education in the United States in a classroom about 300 m (1,000 ft) inside the Edgar Mine. Representatives Doug Lamborn (R-CO), Rob Bishop (R-UT), Cresent Hardy (R-NV) and Ed Perlmutter (D-CO) were on hand for the first ever congressional hearing held in a mine where they heard testimony supporting the Mining School Enhancement Act, which was introduced to Congress by Hardy and Perlmutter on Oct. 9, 2015. The act, which is part of a larger mining development and reclamation reform package, seeks to address the absence of a viable pipeline necessary to replenish current faculty vacancies in United States Mining Schools. “What better place to hold a hearing to discuss the need for future mining engineering experts,” Subcommittee Chair Lamborn said in his opening statement. “It is a need felt by industry, states, the federal government as well as nonprofits.” The Mining School Enhancement Act would redirect millions of dollars in fees that are being collected from active mining operations to fund the research and educational programs at engineering schools with mining programs. Those fees now are being used in the form of grants awarded by the Surface Mining Control and Reclamation Act of 1977 (SMRCA)."

Jan 1, 2015

By L. Zhou, L. Yuan, R. A. Thomas, D. Bahrami

The abstract emphasizes the importance of a calibrated ventilation network model for mine ventilation planning, optimization, and fire simulation. It highlights the impact of continuous airflow monitoring on improving model calibration. The paper discusses an experimental study at the Safety Research Coal Mine (SRCM) to understand the use of continuous airflow data for model improvement. It also addresses practical problems in calibration and tuning using this data, including analysis of air velocity sensor fluctuations and application of sensor location correction factors for accurate average air velocity.

Mar 7, 2022

By R. Wisniewski, S. Schafrik

Every underground coal mine in the United States must deploy and operate a wireless communication and electronic tracking system. This paper addresses the reliability and availability of an installed tracking system and the communications infrastructure that supports it. This paper assumes that the tracking system uses the communication system to perform its operation. A particular interest is the requirements for the systems to operate continuously without failure after a mine disaster for 24 hours, and the requirements in the MINER Act for the tracking systems to be “functional, reliable and calculated to be serviceable” and the communications systems “redundancy.” These requirements imply a certain reliability and availability. This paper describes a quantitative way to assess these systems requirements, using tools that are available to and commonly used by the reliability, maintainability and availability community.

Jan 1, 2014

By Brendan Demich, Brendan Macdonald, Timothy J. Orr, Jonathan K. Hrica, CASSANDRA L. HOEBBEL, Jason Navoyski, Jennica L. Bellanca

The paper describes the process of collecting detailed accounts of near-miss incidents and turning them into impactful visual stories using graphic simulation. The aim is to create high-quality training materials to reduce haul-truck-related accidents and fatalities in mining.

Sep 1, 2023

By S. V. Krishnan

In the upgrading of finely-disseminated iron ores, selective desliming is the critical step which must be controlled in order to achieve efficient flotation. A prerequisite for selective desliming is a properly-dispersed pulp; sodium silicate is commonly used as a dispersant. The mechanism by which sodium silicate acts as a dispersant in the presence of calcium ions was examined by streaming potential measurements, settling tests, abstraction density determinations, selective flocculation tests and scanning electron microscope observations. The study established that calcium silicate precipitates on the mineral surfaces dispersed the pulp. Although sodium silicate was a nonselective dispersant, the addition of corn starch aided the flocculation of goethite over quartz at low silicate additions, but became ineffective at higher silicate levels. A model is presented to explain the dispersant mechanism of sodium silicate in the presence of calcium ion for selective flocculation of iron ores.

Jan 1, 1982

By H. F. Ghezzi

The indirect method of drying coal fines is applied to filter cakes which ordinarily contain 22 to 30% moisture and are not readily transportable. The "Thermal Dryer", which operates on the mass transfer principle, has found wide use in coal preparation plants. The thermal dryer is penalized in operation by the necessity of adding coarse coal to the wet fines before entering the dryer body in order to produce a permeable bed, and thus enable hot gases to uniformly contact the wet mass. The ratio of coarse coal to fines varies from 2:1 to as much as 4:1, depending on the average particle size, moisture, and ash content of the fines.

Jan 1, 1985

By B. Devulapalli

A mathematical model of the industrial hydrocyclone based on fluid dynamics is a better alternative to the currently existing empirical models. The swirling-flow velocities are determined by solving the Navier-Stokes equations with an appropriate turbulence model. The solution of the momentum-balance equations yields the flow field inside the hydrocyclone which determines the particle trajectories, and subsequently the classification curve. The essence of the model is that the physical dimensions of the hydrocyclone and the slurry characteristics can be incorporated, and the influence of these parameters reflects on the flow predictions. The predicted tangential and axial velocities in a 250-mm hydrocyclone are in good agreement with the laser-Doppler velocimetry measurements. Finally, the predicted classification curves show good agreement with experimental data measured on a KREBS Dl0B hydrocyclone.

Jan 1, 1993

By E. R. Dotson

Kaolin is an important industrial mineral. It has unique properties, which combined with its low cost, make it suitable for use in a wide variety of products. Kaolin is defined as "any of a group of clay minerals, including kaolinite, nacrite, dickite, and anauxite, with a two-layer crystal in which silicon-oxygen and aluminum-hydroxyl sheets alternate; approximate composition is AlZ03-ZSiOZ-1/ ZHZO".-The kaolin discussed here is composed chiefly of the mineral kaolinite. Kaolin is also commonly referred to as "china clay". Approximately 4.9 kkg (5.4 million short tons) of kaolin was sold or used in the United States, and .8 million kkg (.9 million short tons) was -exported in 1974. In domestic usage, paper coating and filling accounted for 43% of the total, fol-2/ lowed by refractories, rubber, and ceramics.-Figure 1 shows the amount of kaolin sold or used by domestic producers for specified uses for the years 1963-3/ 1973.- Kaolin was produced at mines in 14 states, but Georgia accounted for 75% of the 1974 domestic production. The average value for all grades was $36.00/kkg 4/ ($32. 67/ton) .-

Jan 1, 1977

By Armin C. Supp

Since 1975, about a dozen high capacity flotation plants have been installed in the Ruhr district. Depending on the size of the preparation plants, the design capacity of the flotation section is between 100 - 150 t/h. The flotation units generally comprise rougher and cleaner stages in which 5 to 6 or 4 to 5 agitators respectively are arranged in line. The unit volume allocated to each agitator is up to 16 m3. The type of flotation machines, the design of these plants and their instrumen¬tation and control equipment are described in detail. The run of mine coal in the Ruhr district is characterized by a wide variety of the volatile matter. Generally, a distinction must be made between coals with more than 30 - 35% V.M., which are preferably used in power station, and coal with lower V.M. content, which are preferably used as coke-oven feed. The difference between these coals in respect to grain-size distribution, ash cotent and flotation properties will also be described in detail.

Jan 1, 1985

By Nikolaos Syrtariotis, Mark Berger, Timothy O’Brien, Vojtech Gall

The Northeast Corridor Superconducting Maglev Project (SCMAGLEV) entails construction of a high-speed train system between Washington, DC and New York City, with the first leg between Washington and Baltimore, MD. This innovative project will shorten travel times between Washington DC and Baltimore to approximately 15 minutes, and connect Washington, DC to New York City in under an hour. In 2021 the draft EIS is expected to be issued for comment with a Final EIS/ROD anticipated by early 2022. This paper provides an update on the project as presented in Gall et al. (2020) and discusses the economic and environmental benefits, preferred alignment alternative, preliminary staging and launching of the TBMs for construction, and preliminary station design.

Jun 13, 2021

By A. Sfougaris

A study on fauna distribution and abundance is being conducted in the Giona Mountain, in central Greece, area of bauxite mining. The specific aims of the study are: a) to estimate and map the distribution of mammals, and especially of the Balkan chamois, b) to estimate and map the distribution and abundance of breeding birds, c) to count the bird species using the area during spring and autumn migration and winter, d) to update the list of mammal and bird species of the mountain, with emphasis on rare and endangered ones, according to 79/409, 92/43 EU Directives and other relevant conventions, e) to compare the bauxite mining areas and species distribution and assess the possible overlap and compatibility of mining activities - species conservation, f) to assess the possible habitat loss due to planned mining activities. All estimations of mammal species distribution and abundance are being carried out by fieldwork using spotlight during the night along selected routes. Especially for chamois, line transects and vantage points with the aid of telescopes and binoculars are being used. Birds are being counted with the point count method in randomly selected plots distributed in all available habitat types and altitudes. The species distribution and mining areas will appear on thematic maps with the aid of a geographical information system (GIS). Finally, solutions for environmentally compatible mining activity in the area will be proposed.

Jan 1, 2007