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By Jorge James

En los últimos 20 años la conflictividad social alrededor de las minas y proyectos mineros ha aumentado debido a diferentes razones. Haciendo un análisis de los conflictos se pueden extraer lecciones que sirvan a las empresas mineras para evitar, o al menos mitigar, conflictos futuros. Esta lista de 50 lecciones puede servir como una guía de lo que hay que hacer, de lo que hay que evitar, o por lo menos de qué temas se deben tomar en cuenta al momento de desarrollar un proyecto minero.

May 10, 2023

By J. E. Nesset

The past 50 years have been a golden era, not just for the CMP but also for the development and success of Canadian technologies in the field of mineral processing. The CMP has played a critical role of technology transfer agent, and the success of these technologies is also linked to the success of the CMP itself. The presentation will cover, in brief, the growth of the CMP from its origins as the Canadian Gold Metallurgists in 1964, with some 39 attendees, to the present day when the annual meeting sees 500 and more from a dozen countries. Also covered will be selected technology success stories from the 50th anniversary volume to be given to all delegates ‘Canadian Contributions to Mineral Processing Technology 1968-2018’. The volume itself highlights some 40 technologies that have been divided into five categories; process water treatment and minesite environment, technology innovations, innovations in operations, technology providers and university contributions. Some international perspectives will also be shared.

Jan 1, 2018

By Paul F. Kerr

The uranium-producing areas near Marysvale, Utah provide an unusual group of veins and replacement deposits associated with a Pliocene-Oligocene intrusive and extrusive igneous complex. Aside from several scattered occurrences in older volcanics, uranium-bearing veins occur in intrusive quartz monzonite or granite and in nearby rhyolite. The veins in general trend within a few degrees of N55-65°E, are more or less vertical, and are found along the western margins of a quartz monzonite intrusive. The replacement deposits are found in rhyolite intrusives and also in the lower portions of rhyolite flows close to places where veins forming solutions rising through quartz monzonite came into contact with the rhyolite. At least 14 veins have been mined since uranium mining operations began at Marysvale some 16 years ago, while ore has been extracted through about 10 miles of underground workings. The active mmmg area is approximately 3000 feet long and in the central portion 1500 feet wide. Ores have been found over a vertical spread of almost 2000 feet, between the highest occurrence on Jungfrau Hill ( ca. 7200 feet) and the deepest discovery of ore in a drill hole near the Prospector Mine (ca. 5200 feet). Under existing mining and marketing conditions, mining along the veins in the main area appears to have reached an economic limit at about 500-600 feet below the surface. However, orebodies in the rhyolite and in the upper portions of veins close to the rhyolite are subject to active mining. Isotopic dates indicate that the uraninitebearing veins and replacements are late Miocene or Pliocene (ca. 10-13 m.y.), the rhyolite is Miocene (avg. 17.5 m.y.), and the quartz monzonite and granite intrusives are late Oligocene (23.6 to 26.0 m.y.). The older Bullion Canyon Volcanic Series which encircles the area is Oligocene (28 to 31.1 m.y.). Two generations of alteration occur: ( 1) Earlier alunitic veins and replacement bodies are found in the Bullion Canyon Volcanic Series, none of which have produced uranium; (2) Later argillic alteration associated with the introduction of uranium is found along veins, replacing glassy rhyolite dikes and replacing phases of the rhyolite.

Jan 1, 1968

By Keith Whiting

The Van Stone zinc-lead mine is located in northeastern Washing- ton in Stevens County. It is about 24 km (15 miles) south of the Canadian border and 48 km (30 miles) west of the Idaho line. The deposits occur in late Cambrian age limestones and dolomites of the Metaline Formation. The bedding controls the trend of the zones containing the lenses of zinc-lead mineralization. The Van Stone property and vicinity is almost entirely covered with glacial drift averaging perhaps 6 m (20 ft) in thickness. Outcrops are very sparse. Outcropping gossan with zinc mineralization was first discovered by George Van Stone in 19 13, in what is now known as the South Ore Zone. Only minor trenching was done at that time. The property was idle until the mid- 1920s when Hecla Mining Co. drove several short adits and performed minor diamond drilling. In 1938, Willow Creek Mines of Nevada Inc. acquired the Van Stone plus adjacent parcels and commenced drilling on the known South Ore Zone. In the course of an expanded drilling program, the nonoutcropping North Ore Zone was discovered and was drilled out along a N30°E strike for about 305 m (1000 ft), beyond which point no mineralization was intersected.

Jan 1, 1991

By Chen Dong, Yang Wenwang, Liu Zhineng, Tan Ming

"To meet the requirement of production expanding of a certain potash ore dressing plant in Xinjiang province of China, industrial test of XCF/KYF-50 flotation machine was performed to process potash ore. The tank of XCF/KYF-50 flotation cell is in U shape, 50m3 of volume. This flotation cell is able to suck slurry by itself, and can be arranged on the same base level without high difference. In this paper, two sets of XCF/KYF-50 flotation cells were adopted to replace 8 sets of 8m3 flotation cell in original flow sheet of flotation. Aeration rate, slurry suction capacity, power consumption and slurry suspension are investigated. The measuring results show the slurry suction capacity of the flotation cell is larger than 12.80m3/min and solid particles disperse evenly in the tank without deposition. Industrial test result indicates that the final grade of concentrate is 26.69% at the recovery of 90.95%, which is up to expected performance. XCF/KYF-50 flotation cell has advantages of high flotation efficiency, significant energy saving and reasonable configuration of automatic control system, this kind of flotation cell can meet the requirement of production expanding of this potash ore dressing plant well."

Jan 1, 2014

By J. H. Lalor

The Olympic Dam deposit was discovered in July 1975 with the intersection of 38 m (125 ft) of 1.05% copper in diamond drill hole RD 1. A further eight holes were drilled with only marginal encouragement to November 1976 when RD 10 cored 170 m (558 ft) at 2.12% copper and an economic discovery was confirmed. The discovery of Olympic Dam is an excellent example of the application of broad-scale scientifically based conceptual studies to area selection combined with the backing of an exploration management willing to support its exploration scientists in testing their ideas with stratigraphic drilling. It also illustrates the persistence required in mineral exploration. The project began in 1969-1972 with the development of a conceptual model for the formation of sediment-hosted copper deposits. This model suggested that the alteration of continental-type basaltic rocks could release copper into solution from which it could be concentrated in favorable stratigraphic positions. In mid-1972, this concept was applied to a review of the Proterozoic and Lower Paleozoic rocks in South Australia aimed at defining targets for stratigraphic copper deposits.

Jan 1, 1991

By Hal T. Morris

The main Tintic mining district in central Utah has produced approximately 13,500,000 tons of ore, containing silver, lead, gold, copper, zinc, and other metals, valued at more than $315,000,000. More than 90 per cent of this ore has come from large, irregular ore bodies that have replaced folded and faulted limestone and dolomite strata. Of lesser importance are replacement veins that chiefly cut contact-pyrometasomatized carbonate rocks and fissure veins that cut altered intrμsive bodies and volcanic rocks. The district is in the west-central part of the East Tintic Mountains, a north-trending fault-block range near the eastern margin of the Great Basin. The consolidated sedimentary rocks exposed at the surface and in mine workings are miogeosynclinal deposits more than 10,000 feet thick that range in age from late Precambrian to Late Mississippian. They are folded and strongly faulted and are partly overlain by volcanic tuffs and agglomerates and by extensive flows of porphyritic and vitrophyric quartz latite, latite, and trachyandesite of Eocene age. All of these rocks are locally concealed beneath thick alluvial deposits of Pliocene and Quaternary age. The Eocene and older rocks are cut by dikes, sills, and small stocks of porphyritic quartz monzonite, monzonite, and latite, which are genetically related to the ore deposits. The district is inactive except for the production of halloysite clay and for minor leasing activity and exploration ventures. Several exploration targets remain untested.

Jan 1, 1968

By E. Cameron

Yeelirrie lies toward the center of Western Australia, 650 km (404 miles) northeast of Perth (Fig. 1). The ore reserves have been estimated as 52.5 kt (57,871 tons) of contained U3O8, at an average grade of 0.15%, of which almost two-thirds average 0.24% U3O8. the ore body is a thin, elliptical, more or less horizontal sheet measuring approximately 9 km (5.6 miles) in length, between 0.5 and 1.5 km (0.3 and 0.9 miles) in width, and up to 7 m (23 ft) in thickness, extending from the surface to a depth of 8 m (26 ft). In spite of its near surface position, there is only one small outcrop of significant mineralization. Carnotite is the only uranium mineral recognized so far, dispersed through a calcrete horizon, and deposited from circulating ground water which was also responsible for the carbonation of the clays completely filling an Early Tertiary drainage system. Calcrete, as seen at Yeelirrie, is quite distinct from the widespread, thin pedogenic horizons, as it often forms bodies many kilometers in length and up to 20 m (65.6 ft) in thickness, elongated parallel to the drainage lines. It is variously referred to as "valley calcrete" or "ground water calcrete" to emphasize the occurrence and mode of origin. The discovery of Yeelirrie in mid-1971 was the successful culmination of a grass-roots exploration program initiated in 1968 as part of Western Mining Cop's program of diversification from its historical position as a major gold producer. The object was simply to find an economic uranium deposit - with no constaints other than those normally taken as applying in the mineral search. There was, therefore, complete freedom in the selection of the exploration model, or models, to be applied and the areas to be considered, though the choice was inevitably influenced by both the nature of world occurrences and the local geology. One of the options avail- able was the sandstone environment. Yeelirrie was the direct result of pursuing this line of investigation through three sequential, but quite distinct, stages: first, a regional study; second, establishing a case for exploring the inland drainage systems of Western Australia; and finally, an evaluation of the calcrete environment. An assessment of the potential for sandstone-type deposits in Australia necessitated going back to first principles, since there were no known precedents in this country for guiding exploration and, as a consequence, the search need not be influenced by established prejudices. Previous uranium exploration during the 1950s had been preoccupied with vein-type deposits, and, although the sandstone environment was undoubtedly being examined in 1968, no discoveries had been announced to that time. When considering the necessary ingredients -a source of leachable uranium, a circulating ground water system, and a suitable reducing environment - it could be argued that considerable areas in the eastern part of the continent were theoretically prospective, but basin depth and the extensive superficial cover of Mesozoic and Cainozoic sediments presented considerable practical difficulties.

Jan 1, 1991

By Edward C. Stephens, Robert R. Coats

High-grade copper ore was discovered in 1932 in the long-dormant Mountain City (Cope) mining district, Elko County, Nevada. From 1932 to 1947, the one producing mine in the district, the Mountain City Copper Mine, produced 1,109,878 short dry tons of ore averaging 9.745 per cent copper, 0.274 ounces of silver, and 0.0057 ounces of gold per ton. The Mountain City Copper Mine is developed in eugeosynclinal rocks of Ordovician age, the Valmy Formation, which is part of the upper plate of the Roberts Mountains thrust. On the Valmy were deposited unconformably first, a elastic formation of Devonian or Mississippian age, the Grossman Formation, succeeded unconformably by a ·sequence of three conformable formations, the Banner, the Nelson, and the Mountain City. The Banner Formation probably is early Late Mississippian in age; the ages of the Nelson and Mountain City are not known precisely but are believed to be of Late Mississippian and Carboniferous(?) age, respectively. A thick formation of elastic rocks, limestone, and volcanics, the Reservation Hill Formation, has been thrust over the Mountain City. The age of the Reservation Hill is unknown but is presumed to be Pennsylvanian(?) and Permian(?). Several plutons of Cretaceous quartz monzonite intrude the Paleozoic formations; they and the intruded formations have been laid bare by erosion, and several sequences of volcanic rocks of Miocene and Pliocene age, and perhaps in part older, have been successively deposited on irregular erosion surfaces. The primary mineralization of the Mountain City Copper Mine is believed to postdate the deposition of the Nelson Formation and to predate the intrusion of the quartz monzonite. The primary ore bodies are lenticular in shape and are composed largely of quartz, pyrite, and chalcopyrite. The ore lenses, in general, strike northwestward and dip northward. They occur in the Valmy Formation within a definite stratigraphic sequence composed largely of shales with associated minor quartzite lenses. The ore is epigenetic. The principal ore body, the "200," was completely leached to the 200 level. Abruptly beneath the barren gossan was supergene copper sulfide ore, much of which assayed 50 per cent copper. The secondary copper minerals are sooty and massive chalcocite, bornite, and covellite. The supergene enrichment of the ore may have required a large part of Tertiary time.

Jan 1, 1968

By Marvin P. Barnes, John G. Simos

The Park City District, Utah, is situated in the Wasatch Range at the intersection of the westward extension of the axis of the Uinta Range. Ore has been mined almost continuously from the first discovery in 1869 to the present day, with a total production of over 14 million tons. Sediments of Carboniferous to Triassic age have been folded into the northerly plunging Park City anticline and subsequently modified by thrust faulting, diorite and diorite porphyry intrusions, and strong east-west normal faulting during the Laramide orogeny. Younger andesitic volcanics partially cover the eastern edge of the district. The ore bodies occur as both lode and bedded replacement deposits over widely scattered localities. Near surface, high-grade silver "bonanza" ores were mined in early days from the Ontario and Daly Lodes, which occur along the east-west zone of faulting near the center of the district. Other lode or fissure deposits were found along the Mayflower and Hawkeye faults to the east and southeast. Large bedded replacement silver-lead-zinc ore bodies associated with east-west zones of fissuring, have been mined from favorable horizons in the Park City Formation in the Daly West and Judge mines. A series of long, narrow, high-grade, replacement ore bodies occur in the Silver King mine at a single horizon in the Park City Formation. Ore is currently being mined from strong bedded replacements in the Humbug Formation near the apex of the Park City anticline. Factors controlling ore deposition are: magmatic source, structural feeder systems, and favorable host rocks. Ore deposition along favorable beds is primarily a function of physical conditioning and secondarily of chemical composition.

Jan 1, 1968

By Paul Gemmill

Production was first recorded from the Pioche district in 1864, and it has continued to show an inherent ability to take on new life after periods of depression in the metal markets. Production from replacement leadsilver- zinc sulfide ore bodies in limestones of Cambrian age now accounts for several times the gross value of silver production from rich fissures in Lower Cambrian Quartzite. Aggregate production of some 6 million tons represents a gross value over $100-million. Future output is expected mostly to be from limestone replacement deposits of which the most productive are "channels" of ore up to several hundred feet wide and several thousand feet long with thicknesses from a few feet up to 50 feet. Such channels are restricted to the lowermost limestone bed of the district, about 250 feet above the basement quartzite. The "blotter-like" characteristic of this highly productive Jimesto~e bed in absorbing mineralization is believed to be, at least in part, due to lithology, including free carbon in the bed, which has created a unique set of conditions for delicately balanced mineralizing solutions that rejected any tendency to replace siliceous wall rock and were properly constituted for replacement of Limestone. All recognizable orogenic history is considered to be related to the Basin and Range faulting that created the mountain ranges. The faults developed after mid-Tertiary time and after widespread extrusives that are themselves involved in the faulting. Flat faults, formerly believed to be part of regional thrust faulting, are now interpreted as gravity slide faulting that can be shown to be large in magnitude and not simply local landslides. Large slide faults generally have concealed the great magnitude of mountain-bordering faults. Mineralization that accounts for ore is later than the faulting. Most faults are pre-mineral since they influence the shape of ore bodies, and some clearly have been offset by fault fissures containing ore. Post-mineral movement probably has been an important component of some large, initially pre-mineral faults. A single period of mineralization was begun by the introduction of large quantities of ironmanganese carbonate, and, in places, carbonate manganese with minor values in sulfides. Closely following the carbonate invasion, massive sulfides were brought in, usually replacing part of the carbonate body though in some places the massive sulfides replaced limestone that was not previously mineralized. Manganese mineralization is not a "halo" but leaks of manganese to higher formations and to the surface are the most significant exploration guides. The Pioche district is expected to be long lived with technological developments in ore treatment being important to the exploitation of low-grade manganiferous ores, while aggressive exploration is expected to find important quantities of bedded lead-silver-zinc ores of the massive sulfide type.

Jan 1, 1968

By Daniel R. Shawe

Large tabular beryllium deposits in waterlaid rhyolitic tuff at Spor Mountain, Utah, contain the world's largest known resources of beryllium (as bertrandite). The district also has produced fluorspar and uranium. The largest beryllium deposit is about 2.5 miles long, and known deposits contain many million tons of material with at least 0.5 per cent BeO. The beryllium-bearing tuff (Pliocene?) underlies topaz-bearing rhyolite ( Pliocene?) that contains unusually high amounts of beryllium, fluorine, and uranium, and overlies other volcanic rocks (Pliocene? or Micocene?) and marine carbonate and elastic rocks ( Paleozoic). The deposits occur in hydrothermally altered tuff only where it contains abundant carbonate pebbles eroded from the Paleozoic rocks and where the tuff was deposited as thick layers in now-buried paleovalleys. Basin and Range faults, thrust fa ults, and possibly strike-slip faults formed in this part of the Basin and Range province during the late Tertiary, and volcanic rocks were extruded. Beryllium mineralization probably occurred during this episode. Undoubtedly the beryllium deposits are related genetically to the topaz-bearing rhyolite, but the details of their genesis are not certain and probably are complex. Beryllium deposits are close to major faults, and locally the beryllium is concentrated at faults, indicating fault control of mineralization. Some elements in the deposits, such as lithium, however, are evenly distributed in certain Luff beds and perhaps were introduced prior to faulting. Still other elements, such as manganese and lead, were concentrated in the beryllium deposits and subsequently were leached along late fractures, indicating a period of metal redistribution following mineralization.

Jan 1, 1968

By Charles A. Anderson

Arizona and western New Mexico contain 17 of the 25 leading copper mines in the United States. Production of molybdenite, lead, zinc, and by-product gold and silver is important. Precambrian ore deposits are largely limited to the Yavapai Series in central Arizona and most of the metal production has come from massive sulfide deposits, dominantly pyritic but containing different amounts of chalcopyrite, tennantite, sphalerite, and galena. Their origin has been interpreted by some geologists as hydrothermal replacement of schist, and by others as syngenetic deposits later metamorphosed. Most of the important ore deposits are of Mesozoic and early Tertiary age, dominated by the porphyry copper deposits spatially related to stocks, plugs, sills, or dikes of quartzbearing porphyritic to granular rocks. Host rocks for these deposits include the associated intrusive rocks, Precambrian schist and granitic rocks, Paleozoic limestones, Mesozoic(?) porphyritic andesite, and Mesozoic arkose and siltstone. Chalcopyrite and pyrite are the dominant hypogene sulfide minerals in the porphyry copper deposits, accompanied by minor molybdenite. The Questa deposit in New Mexico is largely molybdenite. Supergene sulfide minerals are chalcocite and minor covellite. Some ore bodies consist largely of hypogene sulfides, some are dominantly supergene sulfides, and others are mixed hypogene-supergene sulfides. Supergene oxide-copper minerals locally are important. Intense hydrothermal alteration accompanied the metallization in all of the porphyry copper deposits; five types are recognized, ( 1) propylitic, (2) argillic, (3) potassic, ( 4) quartz-sericite (without clay), and (5) lime silicate. The origin of the closely spaced fractures that contain ore minerals in intersecting veinlets is debatable; some geologists favor tectonic forces and others suggest cooling of magma or shrinkage due to alteration. Breccia pipes, veins, and limestone replacements account for some important deposits of Mesozoic and early Tertiary age, and presumably these are genetically related to the various intrusive rocks of this age. The St. Anthony deposit of Cenozoic age in southeastern Arizona is unique, consisting of a lead-zinc vein associated with later molybdenum and vanadium oxide-minerals. Cenozoic manganese deposits in western Arizona are an important resource in the Artillery Mountains, but the extent to which they may be exploited is a metallurgical and economic problem.

Jan 1, 1968

By William R. Jones, Robert M. Hernon

This report on the Central mining district of New Mexico is the partial culmination of an intensive U.S. Geological Survey effort dating back some 30 years. Robert M. Hernon went to Silver City in 1948 to finish a detailed restudy of the district that had been started in the thirties by Samuel G. Lasky. He was joined by William R. Jones in 1951, and Jones took over as project chief when Hernon resigned to do consulting work in 1953; it was under Jones' guidance that most of the work was brought to completion or nearly so ( 17, 22-24, 26-30). Hernon returned to the Survey in 1958 to work in .the southern Appalachians. Early in 1965 Jones urged that Hernon be reassigned to the Silver City project to help complete the Professional Paper report on the ore deposits of the Santa Rita quadrangle as well as to take over preparation of the report on the Central district for the Graton-Sales volume. This reassignment was approved, and Hernon began work on the present report. By late June he had completed most of it in draft form, and on June 28 Jones and Hernon left Denver for a short trip to Silver City to fill in a few gaps and to reacquaint Hernon with activities in the district, which he had not visited for 12 years. Late in the afternoon of June 29, 1965, as Bob and Bill were 85 miles short of their destination, their jeep collided head-on with a truck that was attempting to pass another vehicle in a cloud of dust. They both died instantly. As the most recent surviving member of the Silver City project (1958-1962), I was given the honorable though rather sorrowful task of putting the Hernon-Jones report "in shape" for publication. Fortunately the manuscript was already in good shape, so that the task has consisted of little more than minor reorganization and editing, and of preparation of the illustrations, abstract, and bibliography. The sections on wall-rock alteration had been left for Jones to complete in the light of his recently intensified interest in alteration geochemistry (25), and it is in these sections only that. the report may fall short, for they have been filled in from a 1958 manuscript by Jones on the ore deposits of the Santa Rita quadrangle that he intended to revise considerably. The shortcomings, however, are largely in the interpretation, not in the field data. As a brief but accurate summary of what was known about the geology of the Central mining district in 1965, this report stands as a fitting testimonial to the scientific dedication of two exceptional men.

Jan 1, 1968

By Arthur R. Still, Paul Gilmour

The ore deposit of the Iron King mine occurs in a group of steeply-dipping metamorphosed eugeosynclinal volcanic and sedimentary rocks of Precambrian age. Within this sequence, the ore deposit lies at the contact of a unit made up of rhyolitic tuff and interbedded andesite and a structurally underlying series consisting of andesitic tuffs, minor rhyolitic tuffs, and argillaceous sediments. Field evidence suggests that these rocks have been overturned. The ore deposit is made up of a series of overlapping, conformable or bodies consisting of massive pyrite and associated lenses of massive quartz. These contain recoverable amounts of gold, silver, lead, zinc, and copper. A parallel zone of copper mineralization occurs within the hanging-wall rocks. The deposit is considered to belong to a large and important group characterized by mineralogical composition and the lithology and structural type of the host rocks. Evidence regarding the origin of the deposit is reviewed, and it is concluded that the ore bodies were formed through the agency of volcanic hot springs on, or near, a submarine surface of deposition

Jan 1, 1968

By Peter E. Hart

The search for mineral deposits is a difficult high-risk enterprise whose likelihood of success is influenced by a great many factors. Among the most important of these factors are the knowledge and judgment brought to bear on an exploration problem. If, for example, a panel of expert highly experienced geologists could be convened to examine every prospect, it is at least plausible that fewer deposits would be overlooked in the exploration process. Unfortunately, whether a project is undertaken by a private company or a government agency, it is not usually feasible to convene such a panel. Our purpose in this chapter is to describe an experimental system of computer programs called PROSPECTOR that is intended ultimately to provide expert consultation on problems of mineral exploration and resource evaluation. Ideally, PROSPECTOR would serve as a surrogate for a panel of expert economic geologists. However, because the cost of computation is very low and is projected to drop by a factor of about 100 over the next two decades, systems like PROSPECTOR could be made available to the exploration enterprise at large. When consulting about a prospect, the PROSPECTOR system first gives the field geologist an opportunity to tell the program about the most significant features of the site: the major rock types, minerals, and alteration products. The system then compares these observations with a number of stored models of various types of ore deposits and forms alternative hypotheses about the types of deposits that might be present. The system next engages the geologist in a dialogue in order to obtain additional data that would be useful in resolving the multiple hypotheses. The geologist can interrupt the system at any time to obtain clarifications of questions, volunteer additional data, request the reason a particular question has been asked, or obtain a general summary of the state of the consultation process.

Jan 1, 1979

By L. Barry Phelps

The complexity of surface mining operations is increasing as attention is directed towards mining larger tracts of lower grade, higher cost deposits. Large tonnage requirements from these mines necessitate utilization of many large pieces of equipment. This equipment must be utilized efficiently, with production maintained at or near designed capacities. Basically, the problem is to select, size, and schedule equipment to maximize profits and minimize adverse environmental impacts (Anon., 1977). The time, manpower, and cost limitations required to analyze a wide variety of situations and alternatives in planning surface mines have been sidestepped with the application of simulation methods using a digital computer. Since a simulator can be programmed to represent the situations which are to be analyzed, many alternatives can be evaluated in a relatively short time. Input variables are easily changed and the resulting changes which take place in the system can be analyzed. When standard methods of analyses are applied, weeks and many man-hours are involved in analyzing large-scale mining operations. At the same time many simplifying assumptions must be made since these operations are dynamic and transient. Hence, it becomes difficult to make sound engineering decisions and take proper and timely corrective action in the absence of simulation methods. This chapter is concerned with the application of one such method, namely, the open-pit materials handling simulator (OPMHS) developed by the Mining Engineering Section, The Pennsylvania State University (Manula, Albert, and Ramani, 1977).

Jan 1, 1979

By Samuel J. Sims

The Grace mine magnetite deposit, located 2 miles north of Morgantown in Berks County, Pennsylvania, was discovered in 1948 by an aerial magnetometer survey. It is situated on the southern border of the Triassic lowlands section of the Piedmont province. Cambrian sandstones, shales, and limestones overlie Precambrian crystalline rock and were folded and thrust-faulted during the late Paleozoic Appalachian revolution. Late Triassic continental sediments were deposited on the deformed basement rocks and were intruded by Late Triassic diabase dikes and sills before regional tilting and normal faulting occurred. The Grace mine magnetite ore is characteristic of the Cornwall type. The ore has replaced a Cambrian limestone lens isolated between Triassic diabase footwall and Triassic sedimentary rock hanging wall. The ore body is roughly tabular in shape, dips 20° to 30°NE and plunges about 20°N80°E. The ore is granular, fine- to medium-grained, typically consisting of unevenly distributed magnetite in a matrix of light green to white serpentine gangue. Magnetite is the major ore mineral, pyrite and chalcopyrite are common accessory minerals, and pyrrhotite occurs locally. Sphalerite, marcasite, galena, hematite, digenite, and goethite are uncommon. Serpentine, talc, and chlorite are the major gangue minerals; calcite and dolomite are common, and phlogopite, tremolite, and biotite are present locally. Apatite is a common accessory; sphene is rare. Calcium-magnesium silicates were formed first by contact metamorphism of impure limestone by the intruding diabase. Later, the silicates were altered hydrothermally to the serpentine- talc-chlorite assemblage now present. Magnetite, the first ore mineral, formed by replacing serpentine and was followed by pyritepyrrhotite and then by chalcopyrite-galenasphalerite. Marcasite, secondary pyrite, goethite, and hematite are secondary minerals resulting from alteration of pyrrhotite and magnetite. It is estimated that confining pressure was about 1500 bars and the temperature range was 500° to 675°C during ore formation.

Jan 1, 1968

By C. B. Manula

The total systems model for underground coal mine planning and design (Master Design Simulator) is a set of computer programs which encompasses a realistic reproduction of the interaction among the geological, environmental, equipment, methods, and the health and safety aspects of the mining plan (Manula, Rivell, and Ramani, 1975). The total system includes nine major subsystems: geology and reserves, methane generator, roof support, subsidence, production, rail haulage, cost, water generator, and ventilation (Fig. 1). The subsystems themselves are divided into two categories based on the frequency with which they are executed: (1) event-oriented subsystems are executed either independently or at discrete intervals when certain specific events occur; and (2) dynamic subsystems function interactively during the production cycle, transferring data to or requesting data from event-oriented subsystems only when specific events occur (Fig. 2). Each subsystem has been tested and validated independently (Ramani, White, and Sutton, 1974; Ramani and Owili-Eger, 1974; Manula, Mozumdar, and Jeng, 1974a; Manula, Mozumdar, and Jeng, 1974b; Manula, et al., 1974; Manula, Rivell, and Sanford, 1974; Ramani, McClay, and Burgos, 1975; Manula and Owili-Eger, 1975; and Ramani, Owili-Eger, and Manula, 1975).

Jan 1, 1979

By Kent G. Homewood

The well-being of any company is directly related to the well-being of its employees and to the effectiveness with which the personnel resource is managed. In an era when personnel management has steadily become more complex, there is an increased awareness of employee information systems at all levels of management due to: (1) regulations enacted by federal, state, and local government agencies; (2) technological advances within the mining industry which have resulted in the requirement for highly skilled personnel; (3) increasing concern for the confidentiality of employee information; and (4) management's need for information for planning purposes to control costs and for early recognition of trends and potential problems. In the past it was sufficient to maintain records manually. Today computers are necessary to provide information on short notice and effectively manipulate large volumes of' data. This discussion will describe the following aspects of employee information systems: (1) collection and maintenance of information, and (2) applications which include employee health, salary administration, management re- sources, and labor negotiations.

Jan 1, 1979