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By William E. Foreman

Editor's Note: For purposes of uniformity throughout this book, Coal Preparation, 5th Edition, the editors have advocated the use of the U.S.A. Sieve Series of testing sieves (see Table 6-2) as the testing sieves of modem choice. The adoption and use of the U.S.A. Sieve Series and its forerunner, the Tyler Standard Screen Scale, has for over seventy-five years introduced uniformity into reports; has simplified the comparison of results; and has provided control for operation of modem coal preparation circuits. While a full explanation of the differences, and more importantly the similarities of these two measuring systems cannot be stated here, it is felt that a brief clarification of terms is in order. The difference between the U.S.A. Sieve Series and the Tyler Standard Screen Scale Sieve Series is the identification method. Tyler Screen Scale sieves are identified by mesh designation with the width of opening varying by the square root of two, or 1.414 times the width of opening in the previous sieve. The U.S.A. Sieves are identified by openings in millimeters or microns and also arbitrary numbers which do not necessarily mean the mesh count; this series uses width of opening variations in the order of approximately the ratio of the fourth root of two, or 1.189. Tyler Standard Screen Scale and U.S.A. Sieves can be used interchangeably, and to avoid confusion the nameplate of all Tyler Screen Scale sieves show the U.S.A. Number, while all U.S.A. Sieves show Tyler Screen Scale mesh equivalent numbers on the nameplate. INTRODUCTION Sizing is the process of separating mixed mineral particles into groups of particles all of the same size, or into groups in which all particles range between definite maximum and minimum sizes. This chapter applies the modem mechanical screen and the liquid-solid cyclone (hydrocyclone) to the process of sizing solid particles as applied to coal preparation. Screening is a mechanical process that separates particles by size. Modem coal preparation is made possible by efficient sizing. Sizing of coal is defined in terms of the opening through which an individual particle will or will not pass, or as two openings, the larger of which passes the particle and the smaller of which retains the particle. Screening accomplishes sizing by passing coal of a wide range of sizes through a series of screens, each of a decreasing size. The individual screen discharges are then directed into different screen products for subsequent sale or processing. Screening in modem preparation plants is done for the following reasons: 1. Removal of fine coal before a size reduction step. 2. Size separation of the coal into a coarse and fine fraction for sized products or for processing in coarse and fine coal circuits. 3. Recovery of heavy media from heavy media coal cleaning circuits.

Jan 1, 1991

By Bahaa Alyosif, Turan Uysal, Muhammet Kürsat Aydemir, MURAT ERDEMOGLU

 The paper investigates the effect of intensive milling on the conversion of microcline to potassium chloride during chlorination roasting. The study aims to improve potassium recovery by reducing the chlorination roasting temperature through mechanical activation.

Aug 1, 2023

By Joseph J. Garbarino

World demand for phosphate fertilizers has grown at an average annual rate of between 6 and 7 per cent over the past 10 years. In the next five years world demand is expected to at least continue to grow at that rate. Also, the continued need for improved fertilizer materials, coupled with improvements in fertilizer technology, have placed added importance on the use of phosphoric acid as a starting material for high analysis phosphate fertilizers. This demand for phosphates and phosphoric acid must be met by increased production. Increased phosphoric acid production also brings increased demand for chemical processing agents including foam control agents. We at Arizona Chemical Company have closely followed the phosphate fertilizer industries needs. Arizona Chemical Company has been an important supplier of flotation agents to the phosphate industry, primarily from its Panama City, Florida plant. We have also recognized the important role played by foam control agents in the wet-phosphoric acid manufacturing process. We feel it is the responsibility of the supplier of foam control agents to offer specifically designed products that are highly efficient and economically useful. The difficulties involved in evaluating foam control agents in the plant are recognized. Owing to the large number of variables present, and the difficulties in controlling these variables during the period of a plant trial, plant evaluation of a large number of foam control agents is impractical. We have attempted to develop a practical, reproducible, and yet rapid, laboratory evaluation test which correlates with plant performance.

Jan 1, 1966

By J. Groppo, W. Zhang, R. Honaker

"Rare earth elements (REEs) found in coal are in the form of minerals, ion-substitution with clays and organically bound. Rare earth minerals (REMs) such as monazite exist in coal and have a grain size less than 5 microns. Froth flotation was successful in concentrating REMs existing in a thickener underflow material derived from Fire Clay seam coal which contained around 300 ppm of rare earth elements (REEs). Conditioning with fatty acid followed by processing using multiple stages of conventional flotation produced a final concentrate containing 2300 ppm REEs. Using a laboratory flotation column, a concentrate containing around 4700 ppm of total REEs was produced equating to an enrichment ratio of 10:1. INTRODUCTION Rare earth elements (REEs) are becoming increasingly important and have been widely used as raw materials for the production of phosphor, metal catalysts, magnets, and batteries [1, 2]. REE recovery from alternative sources such as coal and coal by-products has the potential to stabilize the economic viability of coal mining operations while providing a dependable supply of critical materials. The average REE content of the world coal is around 60-70 ppm [2]. There are many well-known coal beds with high contents of REEs such as those in the Far East coalfields in Russia (300-1000 ppm), the Fire Clay coal seam in eastern Kentucky (500 ppm), and the Sydney Basin in Nova Scotia, Canada (72-483 ppm) [3-6]. The occurrence of REEs in coal and coal by-products can be classified into three types, i.e., rare earth minerals such as monazite and xenotime, ion exchangeable REEs in clays, and REEs associated with organic matrix. The particle size of the rare earth (RE) minerals in coal and coal by-products is very small and normally in the micron and/or nanometer scales. The flotation technique, which is based on the surface chemistry difference, has been widely used to treat fine rare earth industrial minerals such as monazite, xenotime, and bastnaesite [7-11]. As such, flotation is a promising method for the concentration of REEs from coal and coal by-products. In the current study, rare earth flotation was conducted using the fine coal refuse generated at an operating coal preparation plant treating coal from the Fire Clay seam. REE concentration by flotation required an appropriate amount of grinding and control of the pH value while using typical collectors. Prior to RE concentration, release tests were conducted to evaluate the floatability of the recoverable coal and the REE distribution in the flotation fractions in the fine refuse. Mineralogy of the REE was studied using SEM-EDX."

Jan 1, 2017

By Thomas N. Walthier

Exploration is the systematically financed and technically oriented search for mineral wealth. Almost all established mining companies have an exploration department. The size of a company's search varies over the years as the company's profits, or the corporate philosophy change. While the established mining companies have exploration departments, they are also alert to acquiring discoveries made by others -- especially by prospectors and small companies without the resources to develop their find. The emphasis in some large companies stresses self-generated discoveries while others rely heavily on acquisitions; again, over the years the emphasis may alternate. In the last analysis, essentially all new mineral wealth was found through someone's exploration effort. Before we discuss how exploration is financed, it will be informative to analyze how discoveries have been made and by whom. Recently, the author conducted a survey of randomly selected major mining companies to answer these questions. Most companies responded and many went to considerable effort to give complete and detailed answers. I thank all for their help and cooperation. The questionnaire is attached as Appendix I. Appendix II is a list of the 400 companies that replied in a complete enough manner and format to be analyzed here. The results of the questionnaire are given in Table 1. Over 57% of the new orebodies acquired by 40 major mining companies during the past quarter of a century were generated

Jan 1, 1977

By PDF

Previous work has shown that significant, free milling gold values exist in the Ryan Lode ore. This project used pilot scale equipment to estimate the percentage of gold recoverable by gravity methods from the circulating load of a conventional, closed-circuit, grinding mill. The pilot scale flowsheet employed three stages of gravity concentration, hydraulic classification and batch grinding to simulate a full scale milling circuit. 172 kg (379 lbs) of Ryan Lode ore were processed, having a head grade of 4.8 g/metric ton (0.14 oz/ton). Results showed that simple gravity methods are capable of recovering 45-50% of the gold values in a concentrate grading in excess of 3430 g/metric ton (100 oz/ton). Of the remaining gold values reporting to the classifier overflow solids (80% passing 70 microns, 3.1 g/metric ton (0.09 oz/ton)) 89% were recovered from 48 hour bottle roll tests.

Jan 1, 1995

By H. S. Puttanna

Bound water plays an important role in the processing and utilization of numerous materials and mineral processing systems. The fundamental nature of this near surface bound (vicinal) water is yet to be understood in its complete detail. The objective of this paper is to use dielectric measurements to characterize the bound water near hydrophobic and hydrophilic oxide surfaces. It is anticipated that a combination of dielectric property measurements and characteristic relaxation times will allow for more effective analysis of the interfacial water.

Jan 1, 1992

By F. B. Henderson, D. Bird, P. L. Hauff, E. C. Prosh

A National Aeronautics and Space Administration (NASA)-funded project (NASA Grant #NAG13-02026) is underway to determine the ability of hyperspectral remote sensing to map mineralogy that affects water quality within a watershed and to identify the relative contributions of natural and anthropogenic sources to that drainage. Natural sources, particularly areas of pyritic hydrothermal alteration, have been found by the Colorado Geological Survey to be a significant source, sometimes the only source, for acidity and/or metals in a number of areas of Colorado (Neubert, 2000). This situation undoubtedly occurs in many places in the Western United States and elsewhere where metallic mineralization occurs. Anthropogenic sources arise from mining and other human activities that increase the exposure of acid-generating materials to weathering processes, thereby increasing acidity and metal loading to drainages where that activity is occurring or has occurred. This project is attempting to determine if these sources can be differentiated through mineralogical analysis, in conjunction with surface water chemistry that controls the precipitated minerals, of the impacted drainages by remote sensing techniques.

Jan 1, 2003

By Richard V. Wyman

The genesis of ore deposits has been tied to plate tectonics through differential petrogenesis in subduction zones. However, many mineral districts, especially in the Basin and Range province of United States and Mexico, appear unrelated to any possible subduction zones or to plate boundaries. It is proposed that the pattern of mineral belts is related to mantle plumes which have been overridden by an advancing continental margin.

Jan 1, 1976

By James R. Yancik

Economical and environmental pressures necessitates the recovery of the minus 0.6 mm x 0 coal generated by todays mining machines. This size fraction, dependent on the type of production unit, maintenance of the production unit, and the Hardgrove Grindability Index, can be a substantial portion of the Preparation Plant feed. Historically, dewatering of the collected 0.6 mm x 0 product has often been rather expensive and marginal with respect to surface moisture reduction. The Freeman United Crown II Preparation Plant more than adequately demonstrates that the continuous scroll type centrifuge can dewater 0.6 mm x 0 coal to acceptable surface moisture levels.

Jan 1, 1981

By Bennett D. Lass

A new method for determination of residual flotation oils on beneficiated kaolin clays has been developed. The method, which yields qualitative information, is based on fluorescence measurements employing a spatially resolved, polychromatic illumination source for excitation, and a two-dimensional detection scheme using a silicon-intensified, video imaging device. The method was used to identify residual oils on a beneficiated, Washington County, Georgia, crude clay. The results were compared to a similar qualitative analysis performed via capillary column gas chromatography using an FID detector. The video fluorometry was the preferred method of, analysis.

Jan 1, 1983

By John G. Groppo, Bonnie Webb-Groppo

INTRODUCTION The first portion of this chapter is concerned primarily with the contamination aspects of fine coal cleaning that include both the solids and water discharged as waste products after coal preparation. Topics include characteristics of the water and solids, changes that occur to both of these phases during use and after impoundment, as well as the impact that these changes have on unit operations and the environment. Attention is also given to the formation of acid mine drainage and treatment options that may facilitate reuse of the water. The second part of the chapter analyzes the problem of air contaminants from coal preparation plants including analysis of air pollutants and control methods. An overview of air quality regulations is also presented; most provisions have little or no applicability to coal preparation plant operation but are presented to provide an understanding of end-user constraints. The final part of the chapter emphasizes the long-range problem of refuse disposal and control. An overview of characterization, maintenance, and control of the refuse area is presented, as well as design guidelines. A brief review of stability analysis procedures is also included. PREPARATION PLANT WATER Characteristics of Makeup Water for Coal Preparation There are few specific rules governing the quality of makeup water used in coal preparation processes.'" It is generally accepted, however, that the solid matter content should be less than 5%. The solids concentration in plant makeup water typically varies between 0.25 to 0.9 lb per gal (30 to 110 g/L) and may reach concentrations as high as 1.7 lb per gal (200 g/L). The water used in coal preparation is usually obtained from one or more of the following sources: public supplies, rivers and streams, canals, mine water, and wells. In most cases, water is obtained at the lowest cost including any necessary treatment. A major portion of the recirculated water is clarified by thickeners and settling ponds to remove fine coal and clay particles. Sufficient water is generally available to meet the needs of coal preparation in most areas. It has been estimated that approximately 65 to 70% of the makeup water used in a coal preparation plant comes from surface sources. It is important to note that a variety of substances are commonly found in natural water supplies, whatever the available source may be (Table 11-1). Excessive concentrations of some of those substances can have an affect on plant performance; the effect of specific contaminants on unit operations will be discussed

Jan 1, 1991

By Grant Davis

An International Symposium on the Ecology and Revegetation of Drastically Disturbed Areas was held at the Pennsylvania State University in August 1969. Scientists from 13 foreign countries and 18 states in the United States attended this meeting, which focused on those areas disturbed by mining. The symposium enabled scientists from all over the world to get together for two weeks and discuss informally some of the knotty problems of reclaiming these disturbed areas. Trying to present the results of each of the 64 papers delivered at the symposium might be difficult. So, I will try to bring you up to date on the general status of research on the reclamation of surface-mined areas, particularly in revegetation and hydrology. I will also mention some research that is under way but was not presented at the symposium.

Jan 1, 1970

By Merih Celasun

The literature in operations research centered on mineral exploration has been comparatively limited in view of the significant implications of mineral discoveries upon the national economies in general and mineral industries in particular. Much of what has been published is of somewhat unsure academic nature, indicating to a certain extent the scarcity of industrial applications. Mineral exploration activities present quite difficult operational and conceptual problems. The purpose of this paper is to discuss the principal characteristics of decision problems encountered in planning an exploration program, to indicate an optimization approach to a certain class of allocation problems, and to suggest directions for future research effort.

Jan 1, 1962

By P. Soros

Rich iron ore deposits were discovered during the 1960's in the mountain range of Serra dos Carajas, State of Para, Brazil, near the headwaters of the Tocantins River some 400 miles southwest from the state capital of Belem. (See Fig. 1 and 2). The key to the successful exploitation of this deposit was the development of an efficient an economical transportation system. The rugged terrain, and the dense tropical vegetation of the Amazonian jungle and the irregular coastline with its high tidal range presented severe obstacles to the planning and building of such system. Starting in 1972 extensive surveys and studies were carried out by Soros Associates on behalf of CVRD to determine the optimum way of transporting the ore from the mine site to the markets, most of which are located overseas. Overland transportation to the coast, loading into seagoing vessels and the ocean voyage to the ports of destination was treated as an integrated system in these studies.

Jan 1, 1986

By J. G. Groppo

Froth flotation has been shown to be an effective method for reducing Loss-on-Ignition (LOI) of ponded or landfilled fly ash. Reduction of LOI is required for many fly ashes, particularly those produced from low-No, burners, in order to meet ASTM requirements for use as a mineral admixture in Portland cement concrete. An additional ASTM requirement, fineness, is critical in determining end use applicability, and in many cases, classification of fly ash is necessary to produce an acceptable product. Hydraulic classification has been shown to be a simple, cost-effective method for classification of a variety of minerals including silica, phosphate, mica, coal, etc. and has shown to be similarly effective on fly ash. The combination of froth flotation and hydraulic classification facilitate the production of a high quality pozzolan that meets or exceeds ASTM specifications. This combination has been rigorously evaluated and results of pilot-scale testing are presented. Pilot scale testing was conducted on fly ash from two active utility storage ponds and demonstrated that high quality, consistent pozzolan could be produced using APT's Fast Float? Technology. Along with the pozzolan, additional production of aggregate for masonry mortar and a low sulfur, medium Btu fuel were also demonstrated. The Fast Float? process incorporates several simple unit processes to ensure pozzolan consistency; classification controls particle size distribution which is critical to achieving early strength, flotation controls the grade with respect to L.O.I. (Loss on Ignition) while dewatering controls the moisture content.

Jan 1, 1998

By P. W. Erickson

Development of the Twin Buttes mine entailed the largest known preproduction stripping job in the history of mining. It linked earthmovers and conveyor belts in a new approach to development of a pit that may reach, or even exceed, dimensions of 1 x 1-1/2 miles at the surface and go as deep as 1800 feet. The orebody to be stripped was covered by an average of 460 feet of alluvial gravels, which presented an initial stripping job of great magnitude. The initial pit layout and the original time schedule established early in 1965 called for the excavation and disposal of about 250,000,000 tons of alluvial overburden before the end of 1969. Allowing about a year for equipment delivery, this schedule left four years to do the job averaging about 62-1/2 million tons per year. In 1964 when The Anaconda Company undertook the development of Twin Buttes, it was recognized that special planning was necessary for the disposal of waste material and tailings. Environ- mental control was a prime consideration and is particularly sensitive in the Twin Buttes area due to the proximity to residential developments. Disposal of the 250,000,000 tons of alluvium, as well as future rock and tailing waste material, presented a problem which Anaconda engineers resolved by designing a plan to spread out much of the alluvium over an extended area, including a massive 11- 1/2 mile dike system which will impound mill tailing in three basins. The tailing will be impounded behind these-dikes to avoid wind exposure and blowing. The dikes also serve as a

Jan 1, 1974

By H. G. Fleshman

The economics of western sodium bentonite (also known as Wyoming Bentonite) is covered from exploration to delivery to the final user. Included are costs of exploration, evaluation of ore bodies, mine permitting, stripping, loading, hauling through stockpiling, blending, processing and shipping. Since western bentonite is one of the industrial minerals marketed throughout the world, the various markets and freight costs are included.

Jan 1, 1984

By Wen L. Chen

The steam coal quality is less stringent than metallurgical coal quality. The steam coal is prepared either by cleaning full size range of raw coal or cleaning coarse coal only, leaving the fine coal raw. The latter scheme is more cost competitive. It is particularly applicable to U.S. eastern soft coal where low ash coal is concentrated in fine sizes. For raw coal size separation, a recently developed Rotating Probability Screen, developed by the British Coal Board, may be advantageously used for easy change of raw coal separating size and to avoid screen deck plugging when handling wet and clayey raw coals.

Jan 1, 1983

By Carl G. Schwenk

Rusk County is located in the northwestern portion of the state of Wisconsin, roughly 130 miles east of Minneapolis (Figure 1). The topography is generally flat with dairy farming the principal activity. Forest and swamp lands are common, as well as pasture and cultivated ground. Rusk County falls near the southern terminus of the Precambrian Shield and is covered by a thick layer of glacial drift. Outcrops are quite rare, but the few available exposures indicate that the subsurface is comprised of steeply dipping metamorphosed volcanics and sediments of Early Proterozoic age. A thin section of flatlying Cambrian sandstone is sometimes found directly under the glacial till. The depth to Precambrian basement has been recorded to be as great as 150 feet beneath the surface.

Jan 1, 1976