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By H. B. Oblad

Coal/pyrite fines were froth floated in a laboratory cell to examine the rate of pyrite recovery during conventional coal flotation. The effects of collector, particle size and carbon to total sulfur ratio on the kinetics of recovery were investigated. These data coupled with microscopic examination suggest that miniscule amounts of coal that remain attached to the pyrite surface affect the rate of flotation of pyrite.

Jan 1, 1985

By G. T. Adel, P. E. Richardson, R. Pazhianur

Cathodic protection using impressed current was employed to reduce mill wall wear during ball milling. Wear rates were determined from weight-loss measurements made on four 1-in.-diam mild steel coupons that were installed flush with the interior surface of the mill wall. Grinding tests were conducted on quartz, pyrite and quartz-pyrite mixtures at pH levels of 4.6, 7.1 and 9.2. Cathodic protection was shown to reduce mill wear by 30% to 60%. An examination of the coupon surfaces using scanning electron microscopy showed that cathodic protection greatly reduced pitting corrosion. The presence of a sulfide mineral, such as pyrite, was found to increase the wear rate significantly, possibly due to galvanic interactions. It was also found that the wear rate is significantly higher than the sum of abrasive wear and the corrosive wear, due to a synergistic effect.

Jan 1, 1998

By Z. Y. Hu

This paper reviews the past and presents the present state of industrial minerals in China. The resources, reserve and production of major non-metallic minerals are given. The mining and milling operations are reviewed. The future development and plans of Chinese non-metallic minerals industry are summarized.

Jan 1, 1990

By J. G. Groppo

The Andritz Ruthner Inc. hyperbaric filter was evaluated at a pilot scale for dewatering fine coal cleaned by froth flotation. The pilot scale dewatering testing was conducted at a solid feed rate ranging from 100 lbs to 200 lbs/hr-ft2. Effect of hyperbaric operating parameters and addition of various surfactants and flocculants were evaluated on dewatering of fine coal. The tests data indicated that for the minus 100 mesh and minus 28 mesh clean coal product, the Andritz hyperbaric unit provided filter cake containing 23 percent and 14 percent moisture, respectively.

Jan 1, 1996

By E. F. Draskovich

In 1984 a high temperature heat recuperation system was installed in the pellet plant of the National Steel Pellet Company located in Keewatin, Minnesota. The system is similar to those of Cleveland Cliffs Empire and U.S. Steel's Minntac operations. It recovers hot process air from the cooler by induced flow, and directs it to an intermediate zone between the drying and preheat zones on the grate machine. This system recently underwent further modifications in April 1985, following initial operation in 1984. The M. A. Hanna Company, which manages the property, developed the design criteria and made the subsequent recommendations for modification through its research facility in Nashwauk, Minnesota.

Jan 1, 1986

By Slobodan Vujic, Goran Cirovic, Dragan Radojevic

Mine production systems (MPS) are characterized, more or less, by the following properties: uncertainty, subjectivity, impreciseness, polysemy, instability, indefiniteness and lack of data. From modern study aspect these MPS mathematically belong to the class of fuzzy systems. With this in mind, the usage of fuzzy sets is recommended as a methodology that treats impreciseness, indefiniteness and complexity of mine production systems in a satisfactory manner. Fuzzy modelling, discussed in this pa- per, is applied as a mathematical implement. The objective of the paper was to show production optimization in practice on the ex- ample of bauxite open pits where fuzzy linear programming (FLP) was used following the criterion per income. The variables in criterion function are linguistic variables while both variables and variable restrictions are presented by triangular fuzzy numbers (TFN). The term "satisfactory income" presented through triangle fuzzy numbers was introduced instead of "maximizing the income". sensitivity of the obtained solutions has been analysed

Jan 1, 1996

By J. D. Miller, C. L. Lin

"The use of 3D X-ray tomography analysis for plant-site characterization of coarse particles at a sampling rate of about 3 kg/min for particles ranging in size from 150 mm to 1 mm at a voxel resolution of about 150 µm is now possible. This is quite a significant advance in X-ray tomography technology and promises to be useful for plant-site coarse particle characterization—size, shape, composition, density, texture, grain exposure and mineral liberation—with a response time of minutes after receiving the sample. This paper discusses applications in the mineral industries, including the coal industry, aggregates industry, metal mining and the processing of industrial minerals.IntroductionPlant-site characterization of coarse particles at coal preparation plants, crushed stone/aggregate plants and mineral processing plants is needed to improve plant capacity, product quality and/or process efficiency. Not much online coarse particle characterization is being done at these plants. Only some limited information regarding particle size is obtained online from reflected light images using analyzers such as the OPSA, Split and WipFrag™ analyzers. Even the laboratory analysis of coarse particles has been difficult because of the large amount of sample required to ensure statistical significance of the results. During the past several decades, laboratory 3D characterization of particles from energy and mineral resources by X-ray tomography has been demonstrated and used to good advantage (Miller and Lin, 2004, 2009).Three-dimensional X-ray tomographic analysis has its origins in the medical services industry, where it is used to provide internal images of the human body. It has since been developed for nonmedical applications as well (Banholzer et al., 1987). Figure 1 shows a schematic diagram of the cone-beam geometry micro-CT system. In our case, X-rays from a microfocus X-ray generator are partially attenuated by the sample (a packed bed of particles) that is made to rotate in equal steps in a full circle about a single axis of the particle sample. At each rotational position, the surviving X-ray photons are detected by a planar two-dimensional array (image intensifier) large enough to contain the shadow of the specimen. These two-dimensional projection images are collected using conventional video technology. The video signal for each projection is then converted to a two-dimensional digital array by an image processing system. Finally, a threedimensional image is reconstructed from the collected set of projection images."

Jan 1, 2016

By Rodney L. Stone

As part of an overall laboratory and plant test program to determine mixing and other techniques relating to the more economic use of bentonite as an iron ore pellet binder, a settling test was developed for measuring the bentonite content within a pellet or within a batch of pellets. Between pellet batches, each containing a different level of bentonite, the dry fracture load is directly proportional to the bentonite content between pellets of the same batch, however, the fracture load is inversely proportional to the bentonite level; this is explained by a negative correlation between a pellet's size and its bentonite content and the fact that larger pellets can withstand a higher fracture load than the smaller.

Jan 1, 1968

By Barry Hunsaker

I cannot help but be reminded, as I stand here today, of my boyhood years and heritage, both of which are inextricably tied to this very valley and are, in a: bay, apropos of the theme of this Keynote Session. I remember the scarcity of people. For example, 48, 000 in Phoenix and 436, 000 in the State in 1930 and 65,000 in Phoenix and 499, 000 in the State in 1940. Today Phoenix boasts a population of over 500, 000 and the State a population of 1, 500,000. I remember the' lack of facilities, goods and services, including gas and electric power. I recall stories of my grandfather who had the freighting or teaming contract to haul all the supplies and generating equipment, by wagon mind you, up the old Apache Trail to Roosevelt Dam. . .a three day trip from the nearest railhead which, by the way, was not Phoenix, for it did not merit a railhead on those days, but the village of Maricopa approximately 25 miles south of Phoenix. I remember chopping firewood, heating wash water on an open fire in a No. 3 wash tub at the rear of the house and doing my school homework by the light of a kerosene lamp just 25 to 35 years ago within what is now a large metropolitan area

Jan 1, 1965

By N. Kuyucak

Uranium ores leached with sulphuric acid typically have poor dewatering properties. Applicability of controlled neutralization where gypsum precipitates as crystalline particles, improving dewatering properties of material was examined. Neutralized material was then dewatered using paste thickener to increase underflow density. The objectives are to maximize water recovery due to water scarcity and to produce suitable cemented paste fill material for optimizing underground ore recovery. Work was performed on acidic slurry samples collected after leaching but before the resin-in-pulp uranium recovery. Controlled neutralization greatly reduced volume of neutralization precipitates giving higher densities and improving the dewatering (filtration) properties. As a result it would be possible to increase the water recycled to the mill. Another benefit is that sulphate in the recycled water was reduced to saturation limit minimizing scaling of process equipment. Additional test work is needed; however, Unconfined Compressive Strength results imply that controlled neutralization increases the strength of paste fill and possibly offers opportunities towards a viable backfill option.

Jan 1, 2010

By W. H. W. Husband

Rock salt has been mined by the solution method for many years in many countries. Attempts have been made in the past in Canada and various other countries to produce potash by the' same method. However, only Kalium Chemicals Limited (1) has been successful, possibly because the conditions in Saskatchewan are the most favorable conditions to be found so far for the development of a solution mining method for potash. There are significant differences in solution mining of rock salt and solution mining of potash. First, rock salt deposits are relatively pure in respect to soluble minerals, whereas potash is never found in the pure state and contains Substantial amounts of other soluble minerals, particularly rock salt. In comparison to rock salt, much less potash is dissolved and brought to the surface for the same amount of water circulated through the orebody. The amount of water to be evaporated per unit weight of product is a major difference. Much greater amounts of water must be evaporated when producing potash and the treatment of the brine is more complicated because other dissolved salts have to be separated. Secondly, the rock salt deposits, particularly the domes, are much thicker. Bed thickness is of prime importance because it determines the yield of a well and consequently the economics of the process. Furthermore, as rock salt provides a strong roof structure, larger cavities can be developed and this prolongs the life of the rock salt well.

Jan 1, 1971

By John A. Reeves

The Coal Creek Preparation Plant is the coal cleaning facility of Mid-Continent Coal and Coke Company. Located three miles west of Redstone, Colorado, and at an elevation of 8,040 feet the preparation plant cleans coal produced at the company's Dutch Creek Mine and L. S. Wood Mine. (See Fig.1.) Current production is at the rate of 2500 tons per day clean coal. Plant capacity is rated 350 TPH raw coal. Reject rates vary with mining conditions from 8% to 25%. Factors which influenced the design of the coal cleaning facility were the characteristics of the coal, the location in a tourist oriented resort area, and the extreme winters of the area. Lack of areas suitable for settling ponds and the necessity of keeping effluent waters out of the fishing streams dictated a closed circuit plant. Severe winter conditions, which last six to seven months out of the year and temperatures which have dropped to 40° F. below zero on occasions demanded that the plant be totally insulated and enclosed indoors.

Jan 1, 1967

By F. S. Knoll

Magnetic separation employing superconducting technology is now accepted within the Kaolin processing industry, proving the value of this technology and its ability to operate reliably even at the most remote site. Developments in superconducting magnet engineering, including cryogen free operation, combined with experience in mineral processing enables new forms of Wet and Dry superconducting magnetic separation to be developed. Applying the high magnetic force advantages at 5 T else available from such magnets to other materials is now a reality. High magnetic force mineral separating system developments are reviewed allowing the mineral processor to take advantage of a technology that is no longer confined to the laboratory.

Jan 1, 1997

By W. J. Maloney, H. E. Tuneblom, A. J. Smith

The development of a large regional water supply in Southern West Virginia faced several hurdles. This paper deals with the design and construction of the intake shaft where a combination of cutting edge mechanical excavation technologies were utilized to produce a world class project.

Jan 1, 1999

By David G. Kidd

The principles of Ore Sorting in general and photometric sorting in particular are discussed with detailed reference to the Model 16 machine. The operating principles and design of the Model 16 are discussed and a case study presented to demonstrate the use of sorters to process an industrial mineral. In addition, an economic study is presented, to highlight the benefits of ore sorting, by evaluating the increased revenue that can be achieved using an ore sorter to process a particular ore body.

Jan 1, 1983

The purpose of this paper is to demonstrate how the Computational Fluid Dynamics (CFD) technique can be an attractive approach to evaluate the performance of face ventilation systems. To present the capability of the CFD for such a study and for design purposes, a series of simulations using CFD have been performed at the Department of Mining Engineering, University of Kentucky, for different face ventilation arrangements (e.g. different scrubber geometries, brattice (curtain) and continuous miners locations, airflow quantities, etc.). Results from these simulations are displayed as three dimensional graphs and discussed. Needs for the field validation of these results and refinements of design methodologies are also discussed.

Jan 1, 1998

By Utku Gumus, Ertan Bostanci, Hanifi Copur, Ahmet Rüfai Bilgin, Ugur Altay

"Field observations on replacements of 12-inch constant cross-section double disc cutters in Tuzla Wastewater Tunnel excavated by an EPB TBM with 3.151 mm excavation diameter excavating hard rock are summarized. Cutter life is correlated to rock’s uniaxial compressive strength and Cerchar abrasivity index, and TBM operational parameters. Number of cutter replacements, average cutter replacement rates and types of cutter damages are summarized. The relationships between cutter life and rock properties and TBM operational parameters are analyzed by single variable regression method. Detailed analysis between chainages 1+200 and 1+982 km indicates that average cutter consumption rate is 35.7 m3/replacement (4.6 m/replacement). Cerchar abrasivity index and uniaxial compressive strength does not indicate any meaningful relationship with cutter life. Penetration per revolution and field specific energy might be used for predicting lives of constant cross-section double disc cutters. However, additional data is required to generalize the findings of this study. INTRODUCTION Cutter life / replacement and/or consumption rates in terms of cutter cost and replacement time loses is one of the most important parameters affecting excavation performance of mechanical excavators, especially of TBMs used very widely and equipped with usually disc cutters. Predicting cutter cost is a very important task in especially feasibility stage of tunneling projects. Basic parameters affecting cutter life can be classified into 3 general groups as geological and geotechnical, excavation machine (TBM) related, and operational parameters (Bilgin et al., 2013). The geological and geotechnical parameters are the most dominant ones among them. The machine related parameters should be arranged in accordance with the expected geological and geotechnical conditions for the best TBM excavation performance and minimum cost."

Jan 1, 2016

By Jr. Raleigh

In a cooperative agreement between the U.S. Bureau of Mines and the U.S. Department of Energy, laboratory column-flotation tests were conducted to evaluate fluorosurfactants as selective fine coal flotation collectors. A Middle Kittaning seam coal responded to flotation with both anionic and nonionic fluorosurfactants. These fluorosurfactants were no more selective than MIBC alone. However, for increasing coal yields, nonionic fluorosurfactant systems did not increase total sulfur and ash contents as sharply as MIBC systems. Flotation selectivity also improved slightly when a combined anionic fluorosurfactant-MIBC system was used in acidic pulps (pH < 3.6). While the fluorosurfactants examined will not likely have direct application in current coal flotation practice, other fluorosurfactant systems could eventually prove beneficial for floating fine coals.

Jan 1, 1990

By Manchao He, Xiaoding Xu, Yubing Gao

Based on the geological conditions of the 15,600 working face in Pingba Mine, this paper establishes the mechanical model of the stress distribution in the pre-working face under the influence of mining pressure based on a hemispherical stress distribution theory. The analytical formula for the stress distribution is determined. A numerical model for the mining pressure under the influence of key layer is also constructed, and dynamic stress interruptions under various roof-cutting relief schemes in different horizontal positions are simulated. The stress distribution of the stope under different pressure relief schemes is analyzed and compared with the theoretical results. Results show that blasting roof cutting blocks the transmission of the abutment pressure to the working surface to the coal and rock mass in front of the working face, reducing the significant working face mining pressure influence range, which decreases as blasting pressure relief position moves toward the working face. Stress accumulation in the coal in front of the working face also increases as the blasting pressure relief position moves toward the working surface. Engineering practice results show that blasting cutting can effectively block the propagation of mining pressure, and the stress impact range is shortened by approximately 1/3.

Jul 31, 2021

By Wilson Blake

The occurrence of rock bursts in some deep mines throughout the world constitutes a severe operational hazard. In addition to endangering the safety of the miners, the rock-burst problem is a major factor in mining economically in deep mines because of the loss of production and expense owing to cleanup and repairs following a burst. Developing means of controlling or eliminating rock bursts has been the subject of intensive research for over 50 years. While much has been learned about the effects of rock bursts, little is known about their basic causes; hence, control measures have been at best only partially effective--attested to by the number and severity of bursts that continue to occur throughout the world each year. In the Coeur d&apos;Alene mining district of north Idaho, the rock-burst problem continues as the silver and lead veins persist at depth. These veins are presently being mined at greater than 7,000 feet below the surface and will be mined to some 10,000 feet in the future. The majority of rock bursts in this district occur in pillars. While pillar bursting has been essentially eliminated in some deep-mining districts by longwall techniques, modification or application of this technique to the thin, irregular, and near vertically dipping veins of the Coeur d&apos;Alene district has not been found to be practical. The creation of pillars is a consequence of the horizontal cut and fill mining method used. Figure 1 shows a vertical longitudinal projection of the silver vein at the Galena mine, illustrating the mining method. Stoping progresses between raises and is carried upward between levels. A horizontal pillar is created as a stope approaches a mined-out level. Recent broad-band micro seismic monitoring of rock-burst-prone stopes by the Bureau of Mines has shown that potential burst zones could be delineated weeks in advance of a burst and that a definite sequence of events took place prior to the occurrence of a pillar burst (1). Hence, time was available for control measures to be effected when a stope pillar reached a critical burst geometry.

Jan 1, 1971