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By M. F. Dibble

The Fosfago phosphate rock concentrator is located in the state of Goias, Brazil, 300 km south of Brasilia. The ore is from an enriched carbonatite, which was discovered in 1971 during exploration for pyrochlore niobium ore. The flowsheet was developed in Brazil by personnel from Agrico Chemical Company and Consolidated South America. Engineering was provided by Codemin, a subsidiary of Consolidated, Engineering and construction management was pro- vided by both Agrico and Consolidated personnel who formed the Fosfago team. The concentrator was designed for 500,000 tpy of 37-38% P2Oj dried product. The facilities consist of open pit mining, crushing, stockpiling, and concentration. The product is pipelined seven km to a filtering, flash drying, and railroad loadout station. The plant was successfully started in May 1979.

Jan 1, 1980

By J. LeRoy Peterson

This paper presents some of the theoretical aspects as well as some results of actual plant operation of the Ty-Hukki Classifier. Dual classification steps within a unit vessel are achieved by controlled separation of the sand product under turbulant flow conditions, followed by further classification under strictly laminar flow conditions. Plant operation has shown some of the benefits of the superior sharpness of classification to be reduction of circulating load in grinding circuits, prevention of overgrinding, increase in mill feed rate and consequent reduction in cost per ton of ore.

Jan 1, 1966

By Bruce C. Trent

In order to effectively model subsidence caused by underground openings, a two-dimensional computer code has been developed which couples near- and far-field response. The near-field is simulated by a discrete element block code and a finite difference code represents the continuum region in the far-field. The explicit equations allow rapid and inexpensive solutions to geometries which may lead to subsidence. Two sample problems are presented which illustrate the important features of the code.

Jan 1, 1979

By Henry Chajet

Good morning, it is truly an honor to have been invited to speak before you today Before I begin my update on MSHA's activities, I?d Like t o quickly say a few words about the American mining congress and its mission in Washington, AMC is a national trade association representing most of the producers of the nation's metals, nonmetals and coal, we also represent the manufacturers of mining equipment and supplies and the financial and consulting institutions which service the mining industry. It is the diversity of our representation which gives us our greatest strength in our petitioning efforts, the administration and the members of congress know that an AMC position is the result of the careful consideration of a vastly diverse group of mining concerns. Our president, Al Overton, perhaps has the best description of AMC when he speaks of us as "the mining industry's eyes and ears and its collective voice in Washington."

Jan 1, 1981

By David R. Cole

Before discussing some of the specific public relations issues in Colorado mining, I would like to define public relations, identify the "publics," review Colorado's population profile, and outline Colorado's mining history. Public Relations In describing public relations, a definition which is frequently quoted appeared in the PUBLIC RELATIONS NEWS, and is as follows: "The Management function which evaluates public attitudes, identifies the policies and procedures of an individual or organization with the public interest, and executes a program of action to earn public understanding and acceptance..' As you can see, this covers a "multitude of sins."

Jan 1, 1975

By Jess W. Smith

The carbonaceous Monkemeyer sandstone member of the Creede Formation on Bachelor Mountain hosts alteration and mineralization which contrasts with other silver deposits of the Amethyst system. More than 20 million ounces of silver are contained in disseminated mineralization in the volcaniclastic conglomerates and sandstones. Hydrothermal fluids entered the Creede Formation directly from the Amethyst fault system and mixed with flowing meteoric ground waters trapped beneath the Monkemeyer sandstone. Portions of the basal rocks of the Creede Formation were argillically altered by more dense acidic fluids generated by boiling. The carbonaceous base of the Monkemeyer and much of the conglomerates below were mineralized and well silicified. Deposition of the mineralization resulted from two processes: (1) reduction by carbon in the Monkemeyer, and (2) fluid mixing in the conglomerates. Monkemeyer mineralization is confined to the carbonaceous basal material and silver content is relatively consistent. Silver is contained in acanthite which is commonly associated with traces of galena, chalcocite, covellite and sphalerite. Fluid mixing and mineral deposition in the poorly sorted conglomerates was controlled by the highly variable porosity and permeability. Anomalous silver contents are dispersed throughout a large volume of conglomerates but zones of higher silver content reflect the crude layering of the conglomerates. Acanthite is finely disseminated in pore spaces and partly replaces some detrital magnetite. other metallic minerals are rare in the main zone of mineralization.

Jan 1, 2013

By J. P. Morgan

The Vesta Preparation Plant of the Jones & Laughlin Steel Corporation is located on the Monongahela River, eight miles south of Brownsville, Pennsylvania. This plant is capable of cleaning 2400 NT/hr of a mixture of Pittsburgh seam high volatile coals from the Vesta and Shannopin mines to produce a metallurgical coal of 6.75% ash and a steam coal containing 14% ash. Heavy media vessels are utilized to upgrade the coarse coal while launders and tables. handle the -1/4" fraction of the raw coal feed. Cleaned -coal goes to boot classifiers where the +48 mesh material settles and is removed by bucket elevators. This 1/4 x 48 mesh material is then sent to centrifugal driers for dewatering. As designed, the minus 48 mesh fraction overflows the boot as a 7 to 8% solids slurry and is recovered by cyclones and a thickener and dewatered by filtration. The-products of the heavy media circuit, the launder-table-boot-drier circuit and the cyclone-thickener-filter circuit are combined to constitute the shipped metallurgical coal. This Vesta-Shannopin mix is combined at J&L's Pittsburgh and Aliquippa Works with purchased low and medium volatile coals for the production of metallurgical coke.

Jan 1, 1962

By Ronald C. Severson

Crystals of native gold occur in placer-type deposits. Gold, as a pure metal, is the most malleable metal known; therefore, delicate gold crystal forms should not survive mechanical transport and concentration processes involved in placer formation. To test the hypothesis that the crystalline gold is currently forming in place, two active gold-placer operations and an unmineralized background area in Alaska were examined. At these sites, rock outcrops, soil profiles, and native vegetation were sampled. At one sampling site, the soil was panned and yielded crystalline gold, as well as the more common rounded nuggets. The plants and soils were analyzed for their major, minor, and trace-element contents, especially gold. Two procedures, one a simple demineralized water leach and the other a partial digestion with acetic acid and hydrogen peroxide, were also used to extract gold and various anions from soils. The water-extractable gold ranged from <0.02 to 15.0 ppb Au in the extracting solution. This represents as much as a 104 enrichment in gold over average river water. This extractable gold is probably available to the native vegetation. Gold concentrations in the unashed dry plants from the two placer sites ranged between 0.4 and 106 ppb compared to a background range of <1 to <4 ppb Au. The presence of dissolved organic matter in the soils is thought to be responsible for the dissolution, transportation, and precipitation of gold in these placer soils, and this process is presently active in these soil profiles.

Jan 1, 2013

By J. P. Vandenhoeck

Sizing devices used commercially are unfortunately not 100% efficient, the splits that can be obtained are usually inferior to the results obtained in the laboratory. Often the capital and operating costs of equipment capable of high sizing efficiency cannot be justified by the economics or requirements of the process. To reconcile the desired sizing efficiency needed to obtain optimum process requirements with the sizing efficiency of equipment economically practical, it is often necessary or desirable to predict the gradation and weight splits of the products obtained based on the expectant efficiency of the contemplated sizing device or method. The less efficient the sizing device one must employ, the more important it is to know the results that may be expected for the establishment of the optimum flow sheet and the more difficult it becomes to estimate the results accurately. Air classification equipment which sizes materials by opposing the drag force created by an air stream acting on a particle with a combination of gravitational, inertial or centrifugal forces are substantially less efficient than, for example, a laboratory sieve analysis. Air classifiers allow oversize material to contaminate the fine fraction and leave undersize material in the coarse fraction. The techniques employed to predict the gradation and weight splits obtained from air classification outlined below are adaptable to other sizing devices less than 100% efficient such as screens, sifters and wet classifiers.

Jan 1, 1965

By Paul E. Epstein

Despite the controversies that have surrounded asbestos over the past 20 to 30 years, no knowledgeable authority has doubted the usefulness of this material. Were it not for the health risks associated with the manufacture and use of asbestos products, its physical and chemical characteristics would continue to be hailed as an undeniable boon to mankind. However, it has become clear over the past 30 years that like other major contributors to our modern industrialized society, asbestos must be handled responsibly and with the full understanding that lack of care can lead to injury, suffering and death. In this sense, asbestos shares characteristics with nuclear power, pesticides and even motor vehicle usage. It is unlikely that modern society would be willing to walk away from the benefits bestowed by any of these valuable resources. Rather, the appropriate response to the identification of danger is to define the type of risk, quantify its incidence, search for methods of decreasing the risk and implement programs to achieve the goal of minimization of risk. We should recognize at the outset that the risk cannot be diminished to zero without elimination of the material entirely from our midst. The concept of acceptable risk is a complex issue involving medical, legal, financial, moral and even psychological factors that defy precise quantification. In essence, the major danger produced by exposure to asbestos is its potential effects on the respiratory system. Despite the fact that asbestos workers have constant skin contact with the material and porbably swallow it in the course of their activities, inhalation of the fibers is recognized as the major health risk associated with its use. Aerosols of asbestos are inhaled not only by miners, millers and fabricators but also by urban dwellers who have no direct occupational contact with the material. This occurs because asbestos has been applied to our buildings and has been used in a wide variety of products that touch our daily lives. While it is estimated that three to four million people in the United States have been occupationally exposed to asbestos, the number who have been non-occupationally exposed is many times that number.

Jan 1, 1984

By James W. Mitchell

On December 2, 1942, a scientific team lead by Nobel Prize winner Enrico Fermi first initiated and controlled a self-sustaining nuclear chain reaction. This historic event occurring beneath the stands of the University of Chicago football stadium instantly created an entirely new and tremendously broad area of technology. Indeed, the event probably changed the course of world history and considering the curret energy shortage, it probably came none too soon. Following many technological breakthroughs in the ensuing years, this event led to the first full scale nuclear fueled electric generating plant. In December, 1957, the Shippingport Nuclear Power Plant became operational and the United States had entered the era of the nuclear fueled electric generating station. Today, only fifteen years later, there are some thirty-five operating nuclear power plants in the United States with another 56 under construction and 116 on order. Still, we are only scratching the surface of this tremendous energy source. In 1970, less than one-percent of the total electric generating capacity in the United States was nuclear fueled. By 1985, it is projected that 45% of our generating capacity will result from nuclear power plants. These projections are based upoa statistics of six months to a year ago and considering the current energy shortage and recent attempts by the United States Atomic Energy Commission (USAEC) to speed the licensing process and encourage standardized plants, the contribution of nuclear power to our total generating capacity may be even greater. In summary, it is obvious that nuclear power is now, and will continue, playing an important role in our future. Those factions of government, industry and the professional community charged with fully developing this tremendous energy source must deal with it rationally, logically and expediently. The various environmental considerations in nuclear plant siting play an important role in the overall plan.

Jan 1, 1974

By Rudolf Fahn

Bentonites are best suited for the preparation of acid activated clays with efficient adsorption properties. They are weathering products of acid volcanic ashes and their natural deposits are world-wide spread. The main constituent of bentonite is the aluminium hydrosilicate nontmorillonite with a high ability to swell. Süd-Chemie owns bentonite deposits in Germany and subsidiaries in Italy, Mexico and Arizona.

Jan 1, 1979

By L. A. Garfield

Since the start of mining operations at White Pine in 1953, over 22 miles of drifts have been driven for the purpose of developing the ore body. The drifts, normally driven in multiples of three or five headings, serve as conveyor belt routes, ventilation ducts, equipment and haulage roads, and initial access to mining blocks. Development openings in the flat-lying, bedded ore body are driven in rectangular section from 16 to 32 feet wide and from 8. 5 to 16 feet high. The floor level normally coincides with the bottom limit of the chalcocite values and the roof or back is carried at the most competent stratum adjacent to the top of the ore. A development front consisting of five headings and associated crosscuts is advanced at an average rate of about 100 feet per month using conventional drill and blast techniques and equipment. The cyclic nature of the functions involved in driving the openings and the need to include them in production schedules preclude significant improvements in advance rates using current drill, blast, muck, and haul sequencing.

Jan 1, 1969

By Z. Hladysz

It is common to nine a coal seam affected by previous extraction of a coal seam below. As a result of that severe problems may occur during the extraction process. This paper presents the analysis of undermining effects based on field observations. A simplified method for the evaluation of risk in undermining operations is presented and predictions of the degree of possible damages to the undermined coal seam is given.

Jan 1, 1985

By James K. A. Harral

The growing national concern over energy has aroused a great deal of interest in the most efficient and least costly way to use our remaining fossil fuel reserves. A number of studies have been published which compare the overall thermal efficiency and cost of gas and electric energy. These studies have been carried out by a wide variety of organizations including Oak Ridge National Laboratory, The Rand Corporation, The Stanford Research Institute, and The Institute of Gas Technology. This paper is an attempt, by PGandE, a large combined gas and electric utility serving most of the northern and parts of central California, to compare the cost and efficiency of gas and electric energy for certain residential appliances using actual operating data and financial statistics for the year 1974, and thereby develop some guidelines for future energy developments utilizing these limited fossil resources. The appliances chosen for the study were kitchen ranges, clothes dryers, hot water and space heaters. These appliances were selected because they can be served with either gas or electricity and they account for approximately one-third of PGandE&apos;s total residential electric sales and nearly all of PGandE&apos;s residential gas sales.

Jan 1, 1976

By B. N. Everett

The growing role of Colombia as a major supplier of internationally traded steam coal has been widely discussed in the industry. Although Colombian coal has been produced and exported in small quantities for a number of years, Colombia&apos;s position as a major coal exporter began in earnest in 1985 with the first commercial exports from the Cerrejon North Block Project. By way of background: ? The mine is located on the Guajira peninsula in Northeast Colombia, about 90 miles from the coast, as shown in Figure 1. ? In addition to the mine itself, the project involves construction of a dedicated railroad and port, which form a modern, efficient and integrated system. ? The Project is embodied in a 50/50 Association Contract between International Colombia Resources (Intercor), a wholly owned subsidiary of Exxon, and Carbocol, the Colombian state coal company. Intercor and Carbocol share investment and operating expenses equally and Intercor has the additional responsibility of managing operations on behalf of both partners. Each partner is entitled to 50% of the coal produced, and each markets its share separately. ? The project is a multi-seam, truck and shovel operation, based on large reserves (2-3 billion tonnes&apos;) of high quality bituminous coal. ? Exports began in the first quarter of 1985 at modest levels through what we call Early Coal Facilities, designed and constructed apart from the permanent coal handling system. ? Production will increase rapidly in each of the next few years, reaching the design capacity of 15 Mt per year in 1939. Based on available resources, however, the resource will support expansion, and continued growth n production into the 1990s appears feasible.

Jan 1, 1986

By John P. Capp

In recent years limited markets have been developed for fly ash, the dust removed from coal-burning powerplant stacks, but most of it is still dumped in spoils areas at a cost ranging from 20 cents to $1.75 per ton. Aside from this cost, the creation of huge spoils areas can present a considerable aesthetic problem. Since the present annual fly ash output of about 20 million tons will probably reach 30 million by 1970, and because satisfactory disposal areas are becoming more limited, markets for much larger quantities of the waste are needed to keep disposal costs from becoming a significant economic factor in coal-burning powerplant operation. Current stress on air-pollution control and beautification, plus the vital need for good powerplant economy, makes it imperative, therefore, that coal producers and consumers expand markets and develop new applications for fly ash. Markets for established uses can be increased by making a greater effort to sell fly ash. New large tonnage markets for fly ash should be sought via more intensive, coordinated research. The economics of fly ash utilization underscores the vital role that must be played by research. To be competitive with other products, processes for the conversion of fly ash into marketable materials face difficulty in regard to two important economic factors--transportation cost and product utility--the other economic factors are favorable. Raw material costs of fly ash, for example, are quite attractive, and supply is no problem because there are many coal-burning powerplants in operation and many more are planned. Demand for products made from fly ash will grow if their utility is established and a good sales program is initiated. The major problems then are transporta¬tion costs and development of useful products.

Jan 1, 1966

By B. V. Clingan

A practical application of recent design concepts makes it possible to design a column cell to fit a specific set of conditions. The design and operating parameters Of a column cell installation that replaced a conventional two stage copper flotation cleaning circuit at MAGMA COPPER COMPANY, SAN MANUEL, ARIZONA using these design concepts is described. A survey of other mineral processors using column cell technology was conducted. The results of this survey will also be discussed.

Jan 1, 1987

By Thomas E. Garnar

Mineral sand products have been produced from beach sand heavy minerals for nearly a century. These minerals have specific gravities of 3.0 or higher and are extremely resistant to weathering. The most common economic heavy minerals are ilmenite, leucoxene, rutile, zircon, stauarolite, monazite, garnet, and the aluminum-silicate minerals. Of these, ilmenite is the most abundant. In some cases a deposit may contain only one or two economic heavy minerals whereas in others five or six may be present. Heavy mineral mining began in the late eighteen hundreds when monazite was mined for its thorium content. This was followed by mining activity on the North Florida coast just south of Jacksonville Beach - where ilmenite and zircon were first separated during the WW I (1,8). Modern heavy mineral mining began in Eastern Australia during the late nineteen-thirties and spread to the United States during World War II. It is the purpose of this paper to review the commercial heavy mineral products, their sources, and their uses.

Jan 1, 1985

By Randhir S. Sehgal

After some decades of lying low and being treated as a second rate fuel, coal is back in the news. Production is rising. Predictions are for an ever expanding use, and they differ only in their rates of increase. Even the FBI is involved in trying to stop fraudulent sales of non-existent coal lands and leases to the innocent. In short, we have a nearly chaotic boom on our hands. Obviously our energy production base is in the process of undergoing a major shift, and the process will present many problems. However, there is little doubt that the industry has the basic strength and organization to be able to deal with the new issues that will arise as a result of these shifts in production and use of coal. After all, it does produce nearly 800 M tpy now, and coal is the single biggest fuel for generation of electricity. This role of coal is illustrated in the table below, which shows the coal equivalent quantities of various fuels used in the production of electricity.

Jan 1, 1980