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By Yu-ren Jiang

Novel compounds of hydroxycarbamoyl carboxylic acids, including 2-hydroxycarbamoyl -3-methlcyclohexane carboxylic acid (HCMC), 2-hydroxycarbamoylmethyl decylen-4-yl carboxylic acid (HCDC) and 2-hydroxycar-bamoylmethyl tridecylen-4-yl carboxylic acid (HCTC) were synthesized. The flotation behaviors of diaspore, kaolinite and illite using these compounds as collectors were investigated. The flotation results revealed that the floatability of the minerals was, in descending order, diaspore and kaolinite, followed by illite, and the ability to collect the minerals was, in ascending order, HCMC and HCDC, followed by HCTC. At a dosage of 2×10-4 mol/L, both HCDC and HCTC show a strong ability to collect diaspore and a weak ability to float kaolinite and illite. The flotation recovery of diaspore is over 90% and that of kaolinite and illite less than 30%. Moreover, Fourier transform infrared spectroscopy (FTIR) spectrum and zeta potential, as well as the adsorption amount, indicated that the adsorption interaction between HCTC and diaspore was primarily a kind of chemisorption in the form of chelate rings, while the interaction between the collector and aluminosilicate mineral was dominated by physisorption. It was concluded that the novel hydroxycarbamoyl carboxylic acid compounds are highly selective collectors for the flotation of diaspore vs. aluminosilicate minerals.

Jan 1, 2011

By J. R. Tonry

In the grinding of dry non-metallic materials such as rocks, ores, gypsum, lime, and cement clinker, it is recognized that only a relatively small portion of the energy is utilized for actual size reduction, and the major portion of the energy used is converted into heat. As a result, heat is generated inside grinding mills imparting to the ground product a higher temperature than that of the mill feed. In some cases, as for instance in grinding cement clinker and gypsum into finished cement, it may be desirable to keep this temperature increase within certain limits, to avoid any change in the properties of the product and, because consumers may specify a maximum temperature of the finished product for reasons associated, with the tulimate use of the cement. The actual proportions of heat and useful work are somewhat indefinite. Some tests have indicated that nearly all the energy is converted into heat, and. other investigators have found that they could account for "everything except the noise." Investigations sponsored by the American Institute of Mining and Metallurgical Engineers, and carried out with an adiabatic calorimeter, indicated that a surprisingly high 19 percent of the energy might actually be used for size reduc¬tion. However, for the purpose of the following discussion it will be assumed that: (Fig. 1) 10% is lost in motor and gears 10% is lost by radiation and convection from the mill body 10% is used for size reduction, and. that 70% of the energy input leaves the mill as heat in the ground. product. A typical example (Fig. 2) would be a 7x22-ft tube mill operating in open circuit, driven by a 400 hp motor, charged with 77,000 lb of grinding media and producing 70 bbl or 26,300 lb of cement per hour. Reducing this cement from a clinker size of 96 percent passing a No. 16 mesh sieve to a specific surface of 3,230 sq cm per gm (Blaine) will increase the temperature of the cement approximately 143F above the temperature of the feed, as explained later. If the tempera¬ture of the clinker therefore is 125F, the finished cement will be 268F, which in some cases may be too hot. : When cement temperatures approach a range during grinding where dehydration of the gypsum becomes a problem, a logical consideration would be some means of reducing the temperature before it attains the range conducive to gypsum dehydration. Regardless of the varying degrees of heat generated within the mill or mills during grindingto various finenesses, consideration of the maximum safe limit for any type of cement being ground, which may vary fromplant to plant, govern in refining the mill circuit to obtain a safe temperature range. All plants are not necessarily required to do the same cooling job, and may or may not use cement coolers following the grinding circuit. (Not discussed in this paper). In the past, various means have been employed for controlling this temperature increase, Such means have included water cooling of the outside of the mill shell; equipping the shell with cooling fins; injection of moisture inside the mill; ventilation through the mill; and., in cases of closed-circuit grinding, drawing cooling air through the classifier; the purpose in all such cases being to remove heat from the grinding system.

Jan 1, 1958

By B. J. Arnold

Prior laboratory work has demonstrated -that much of the fine ash-forming minerals entering a flotation froth are there as a result of water carry-over from the bulk contents of the flotation cell (Arnold and Aplan, 1986a). Using a bank of four 300 cu ft WEMCO flotation cells cleaning a well-liberated Lower Kittanning seam coal, test results show that the sulfur and ash content of the froth is directly related to the water content of the froth (or inversely related to the percent of solids in the froth). Reagent changes which result in a watery froth produce a higher ash content in the froth. A direct comparison of laboratory and plant results show that the standard laboratory flotation test produces a product higher in sulfur and ash than that produced in the plant. Caution should be exercised when extrapolating laboratory test results to the plant situation. A method of estimating coal flotation product quality in the plant based on laboratory tests is given.

Jan 1, 1990

By Georgene Renner, William R. Yernberg, Steve Kral

Advanced Terra Testing (ATT)is a full-service geotechnical testing laboratory. It specializes in rock and soil mechanics and geosynthetic materials testing. ATT provides services to the global mining industry. The company has performed more than 1,000 projects for more than 300 commercial and government clients. Services include coal pillar design testing, leach pad material and performance testing, tailings pile consolidation testing and closure and remediation services. Rock and soil mechanics tests include unconfined and triaxial strength, shear and tensile strength, permeability, index testing, consolidation, liquifaction potential, elastic moduli determinations, heap height versus percolation rate, long-term batch testing and dynamic loading tests.

Jan 1, 2003

By H. E. Wyslouzil

The highly competitive nature of the international iron ore market has forced producers to improve the quality of their pellets. The demand for low acid pellets suitable for direct reduction has resulted in an increase in the number of plants utilizing reverse froth flotation for silica reduction. Column flotation is being favoured for this service due to the low capital and operating cost of the equipment, as well as improved metallurgical performance when compared to conventional flotation cells. This paper describes the benefits of column flotation and discusses some important aspects of circuit design.

Jan 1, 1993

By Harry Leslie Bullock

With silica making up more than 27% of the earth's crust, its oxides amounting to more than 59% of the igneous rocks and quartz the most prevalent of the main free oxides, it follows that the mining engineer' is in constant contact with quartz, mainly as a gangue material to be removed as completely and economically as possible and sometimes as a valuable mineral to be purified' for the chemical,, ceramic or glass industries. Water scarcity under desert or semi-arid conditions, dwindling water supplies and difficulties of wet waste disposal in many locations and trouble from freezing in arctic locations make dry benefication more and more desirable. Advances made during the last few years in apparatus and methods and a steadily increasing knowledge of solid state physics are widening the field open to the economical application of electrostatic separation.

Jan 1, 1967

By Trevor Riters

Advancements in Emerson’s instrumentation technology have brought value and efficiencies to the mining industry. Some think of instrumentation as basic sensors and valves, but with our solutions, we equip operators with real time, accurate, and reliable data that they can use to operate more effectively. Working with Caltrol, an Emerson Impact Partner, we successfully engineered wireless skids for a leach pad to provide precise measurement and control of raffinate solution to many of the large mine sites in Arizona.

Feb 1, 2025

By D. Hong

The leaching behavior of rhenium in ammonium iodide solutions with iodine as oxidant has been studied. Experiments were carried out in an autoclave. The effect of stirring speed, temperature, pH of the solution, iodine and iodide concentrations on the dissolution of rhenium was investigated. It was found that high temperature and high pH of the solutions were essential for the efficient leaching of rhenium. The dissolution rate was found to be dependent upon the concentration of iodine and iodide. It was concluded that the dissolution of rhenium under the conditions studied was controlled by mass transfer of iodine with an apparent activation energy of 15.77 kJ/mole.

Jan 1, 1997

By B. A. Ashley

In 2007, Rosebud Mining Company (RMC) opted to extend the reserve base of Tracy Lynne Mine by developing through a sandstone channel. The extension provided access to approximately 6 million additional recoverable tons (approximately 8 years of mining) which originally had been deemed inaccessible. An evaluation of the mine?s existing ventilation system, which was designed to meet the needs of the original limited reserve, concluded that two ventilation shafts would likely be required to adequately ventilate the projected workings in the expanded reserve. To assist in the evaluation, a ventilation model of the mine was developed using Ohio Automation?s ?ICAMPS MineVent? software based on field data from Tracy Lynne Mine, prior ventilation survey experience at similar RMC mines, and relevant published sources. Model results suggested that the most economical shafts would be an 8-ft diameter return and a 4-ft diameter intake. Unfortunately, issues related to property leasing and shaft site permitting caused construction delays. Therefore, the model was also used and proved to be effective in prioritizing interim ventilation upgrades which could be implemented in order to maintain coal production. Model results indicated that the best interim upgrades included rehabilitating restricted entries and damaged stoppings and replacing the main fan with a higher pressure fan. From late 2010 to mid-2012, all interim upgrades and shafts were implemented. Current models and mine experience indicate that ventilation will not be the limiting factor for mining the additional reserve.

Feb 23, 2014

By Hasan Sevim

This paper summarizes recent developments in modeling of underground coal slurry haulage networks for determination of optimum design and operating parameters. The model presented here is based on a stochastic dynamic programming formulation, applicable in any typical room-and-pillar and/or longwall mining configuration commonly practiced in the United States. The formulation and the structure of the model is general enough to handle design problems involving more than one face and mining method. Given the stochastic operating characteristics and a system layout, the model can be used to determine the equipment configuration and operating regimes that minimize the overall unit cost of coal haulage.

Jan 1, 1983

By James R. Hindman

Vermiculite is the mineralogical name generally applied to a group of hydrated, trioctahedral ferromagnesian aluminum platty or micaceous silicate minerals. In microscopic particles the mineral as mineral is differentiated from montmorillonite by a higher Si:AI ratio of approximately 3:l and a higher layer charge and higher cation exchange capacities. Commercial vermiculite, the vermiculite which is mined, beneficiated, and discussed in this chapter, is an important industrial mineral which is formed by the alteration of macroscopic particles of biotite and iron-bearing phlogopite. In natural form it has the size and shape of mica, while possessing the ion exchangeable properties of zeolites and some clays. Within the internal structure of vermiculite lie water molecules, which when rapidly heated to high temperature, transform into steam causing the vermiculite particles to increase in volume. This process of thermal exfoliation produces a lightweight product which finds use in various construction products, agriculture, horticulture, and other industrial applications. In exfoliated form it has the low density and biological inertness of expanded perlite, while maintaining a chemically active surface. Most of the uses of vermiculite are for the thermally exfoliated material. In addition, the cation exchange potential of vermiculite and its layer-silicate structure are properties which can be used as the basis for numerous products including intumescent coatings and gaskets, inorganic films, and the treatment of nuclear and other toxic waste. When chemically and physically modified, it possesses some properties common to organoclays and synthetic compounds. In high purity concentrates and manufactured products, these properties can be altered and optimized in applications to produce superior performance. GEOLOGY Mineralogy Vermiculite was first described as a mineral by Thomas H. Webb in 1824. Webb believed vermiculite to be a variety of talc and described its diagnostic property of thermal exfoliation thusly: "If subjected to the flame of a blowpipe, or that of a common lamp, it expands and shoots out into a variety of fanciful forms, resembling most generally small worms having the vermicular motion exact." Observing that with one exception, all commercial vermiculite has formed by the alteration of iron-bearing phlogopite, a simple definition of vermiculite might be the alteration product of trioctahedral micas, macroscopic particles of which display marked exfoliation when heated rapidly to temperatures above 374°C (the critical temperature of water). The first vermiculite described was found near Worcester, MA, but it was later pointed out by Brush (1866) that vermiculite had been known for some time in Japan as a children's novelty. Because the techniques for mineral analysis were somewhat primitive com- pared to those routinely available today, and because the structure and crystal chemistry of the micas and related minerals were not widely understood, the early literature generated at least 20 "new" minerals which were nothing more than variations in the color and chemistry displayed by vermiculite. Trade names such as Dugarlite, Mandolitem, Strong-LiteTM, and Zonolitem are sometimes used to denote commercial vermiculite, thermally exfoliated vermiculite and their products. Vermiculite particles resemble mica and vary in color from colorless through tan and green to black, depending on the chemical composition. Most physical and optical properties are close to those of biotite, with perfect basal cleavage, hardness between 1.5 and 2.5 Mohs, and specific gravity between 2.2 to 2.8. Fine-sized particles will feel talcose, especially when wet. However, for commercial vermiculite the diagnostic test is that of thermal exfoliation. Vermiculite can display a wide range of compositions, depending on the composition of the original mica and the change of chemistry during weathering and ion exchange. Chemical data for some commercial vermiculites are given in [Table 1]. There are numerous analyses for vermiculite given in the literature, and the analyses of vermiculites from commercial deposits will fall within the range indicated by the average analysis in the table. Many analyses separate the adsorbed water (H2OP) from crystalline water and water as hydroxyl (H20+). The basis of separation of adsorbed water is generally considered to be 100°C. However, hydrate water within the vermiculite interlayer begins to be lost at 75°C and lower. Therefore, measured water content and loss on ignition are combined in the table as H20[total].

Jan 1, 1994

By H. Y. Sohn

The paper discusses two processes, flash ironmaking technology (FIT) and moving-bed ironmaking technology (MBIT), which aim to reduce energy consumption and greenhouse gas emissions in the ironmaking industry by using concentrate directly without pelletizing and without using coke.

Aug 1, 2023

By Felipe Calizaya, Sekhar Bhattacharyya

Noise-induced hearing loss (NIHL) is prevalent in mechanized underground mines. Federal regulations are often not complied with effectively. Miners are also prone to ignoring administrative guidelines and/or personal protective equipment for hearing conservation. As a result, quality of life among experienced miners plummets while occupational risks increase at workplaces. This research focused on auxiliary fans used in underground mines. These fans work at high rotational speed and generate extremely high levels of noise in close proximity to miners. Silencers used are often of little effect due to poor maintenance. A new silencer is tried in the laboratory with the objective of easy maintenance and resulting reduction of noise exposure for miners.

By Augusto Andres Torres Toledo, João Felipe Coimbra Leite Costa, Luciano Nunes Capponi, Diego Machado Marques

Short-term mine planning to open pit requires defining diglines to orientate the excavation geometry. In deposits with multiple chemical variables, it is necessary to have more rigorous control over the feeding of the processing plant. This study analyzes the impact of incorporating multiple chemical variables, the risks generated by geological uncertainty, and the number and starting point locations of shovels in the sequential design of diglines. The objective is to maintain and preserve the low-grade variability, required tonnage, and continuity in sequentially selecting blocks. To achieve this, the probability distribution function of each chemical variable is used while attempting to maintain the ore grades as constant as possible. As it is difficult to maintain multiple elements with low variability simultaneously, the relevance of each chemical variable in the economic benefit is identified. Weights are assigned to signal the importance of each element based on its significance in the recovery process. Several diglines, consisting of sequential blocks, were generated on the same seed point to meet the weekly ore demand. Optimizing the stationarity of multiple chemical variables, accessing and reducing the geological uncertainty performed through geostatistical simulation of grades and transfers functions, considering the number and location of shovels, while meeting the operational restrictions of the selected blocks. The optimized digline with the multiple grades as stationary as possible is retained. The process is illustrated in a phosphate mine. The results show that the proposed method is viable and allows for a quick solution.

Jun 25, 2023

By N. B. Aughenbaugh

Compacted clays are used as permeability barriers in many mineral engineering projects such as heap leaching, containment ponds, tailings disposal and earth dams. Source materials used for clay liners include a wide variety of sand, silt and clay admixtures that exhibit dramatically different engineering properties when densified. The permeability and plastic properties of fine-grained soils are reviewed with respect to the state of compaction as the water content varies. Be-cause they are weak in tension, compacted clays are susceptible to cracking when subjected to differential flexural movements. Designs of compacted clay liners must include an evaluation of their flexibility which is the ability of a fine-grain soil to bend plastically without cracking. This paper will also discuss the importance of flexibility with respect to soil types, compaction effort, failure mechanism and testing evaluation to the performance of clay liners in preventing seepage of pollutants from a containment site.

Jan 1, 1990

By J. R. Patts, A. B. Cecala, E. J. Haas

Exposure to respirable crystalline silica (RCS) remains a serious health hazard to the U.S. mining workforce who are potentially exposed to RCS [1,2] as various ore bodies are drilled, blasted, hauled by truck, crushed, screened/sized and transported to their destinations. To examine a method for assessing RCS exposure using a NIOSH-developed video exposure monitoring (VEM) technology (referred to as Helmet-CAM), video and respirable dust concentration data were collected on 80 miners across seven unique mining sites. The data were then collated and partitioned using a thresholding scheme to determine exposures that were in excess of 10 times the mean exposure for that worker. Focusing on these short-duration, high-magnitude exposures can provide insight into implementing controls and interventions that can dramatically lower the employee’s overall average exposure. In 19 of the 80 cases analyzed, it was found that exposure could be significantly lowered by 20 percent or more by reducing exposures that occur during just 10 minutes of work per eight-hour shift. This approach provides a method to quickly analyze and determine which activities are creating the greatest health concerns. In most cases, once identified, focused control technologies or behavioral modifications can be applied to those tasks.

By S. J. Schatzel, J. D. Addis, V. Gangrade

In longwall mining, ventilation is considered one of the more effective means of controlling gases and dust. In order to study longwall ventilation in a controlled environment, U.S. National Institute for Occupational Safety and Health (NIOSH) researchers built a unique physical model called the longwall instrumented aerodynamic model (LIAM). The LIAM is a 1:30 scale physical model geometrically designed to simulate a single longwall panel. It has an 8.94 by 4.88 m (29 by 16 ft) footprint with a simulated face length of 220 m (720 ft) in full scale. LIAM is built with critical details of the face, gob and mining machinery, and scaled to preserve the physical and dynamic similitude. This paper discusses the gob-face interaction, airflow patterns within the gob, and airflow dynamics on the face for varying roof caving characteristics. Results are discussed to show the impact of caving behind the shields on longwall ventilation.

By H. Sevim

Belt network simulators developed in the last two decades are reviewed. Critical parameters in belt network design are identified, and the capabilities of belt simulators in providing values of these parameters are investigated. An alternative design model that optimizes values of the critical parameters is introduced. To illustrate the capabilities of the alternative model, a real life case is treated and the outcomes are discussed.

Jan 1, 1990

By A. J. S. Spearing, T. Kostecki, D. Benton

The use of paste backfill in room-and-pillar coal mines in the United States needs to be fully investigated. This paper discusses a series of physical tests that were conducted to examine the support benefits of theoretical paste backfill regimens in Illinois Basin room-and-pillar coal mines, which necessarily included consideration of weak floor conditions. The series of tests included those simulating strong floor conditions, weak floor conditions, under-confined scenarios, and testing of actual coal-based paste backfill samples. The testing indicated that a paste backfill regimen utilizing a minimum backfill strength of 22 psi at a minimum fill height of 50% of pillar height could significantly increase the longterm stability of coal pillars in the Illinois Basin. Considering typical coal wash plant recoveries, 50% fill would be feasible.

Jan 1, 2014

By David M. Sullivan

Jim Walter Resources, Inc., (JWR) a division of Jim Walter Corporation, has 5 underground coal mines in Central Alabama varying in depths from 400-2500 feet. Gas Chromatography plays a vital role in safety and production at each mine. Chromatographic data is used to monitor working areas for safety and proper ventilation and to control the quality of extracted methane for sales purposes. Instruments have a1 so been employed during mine rescue operations. JWR's first Gas Chromatograph (GC) was installed in April 1984 to monitor gob gas taken from longwall gob areas and sold based upon BTU value. The GC allows maximum extraction rate of the gas within the quality guidelines. By late 1985, another system was purchased and both units were upgraded to perform an analysis of indicator gases which may appear during mine emergencies. Each unit has the ability to detect and measure the following gases at almost any level ; Oxygen (021, Nitrogen (N2), Methane (CH4), Carbon Dioxide (C02), Hydrogen (HZ), Carbon Monoxide (CO) , Ethylene (C2H4), Ethane (C2H61, Acetylene (C2H2) and a composite of hydrocarbon threes and above (C3+). The analytical run is accomplished in less than ten minutes and is completely automated. This report will introduce Gas Chromatography as applied by Jim Walter Resources for the analysis of underground mine air.

Jan 1, 1987