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By R. A. Haney

The Mine Safety and Health Administration has developed a model to estimate diesel particulate (dp) exposures in underground mines. The estimate uses either in-mine measured dp concentrations or engine manufacturers' standardized emission data and through a series of calculations estimates full shift dp concentrations by applying standard engineering principles of ventilation, control technology and work cycle. This model, in the form of a computer spreadsheet, provides the mining industry with a method to estimate diesel particulate levels and determine the impact of various diesel particulate controls on occupational exposure to dp in underground mines. A detailed description of the estimator and several examples demonstrating the results are provided.

Jan 1, 1998

By Thomas J. Neil, O&apos

Mine land reclamation is a comparatively new science-Although some mining companies point with pride to reclamation efforts of 20 to 30 years ago these were the exception rather than the rule. In the last ten years the skyrocket of environmental awareness has been awesome to behold. Future shock gripped mine operators everywhere as they struggled to cope with rapidly changing and escalating demands. The initial result was that two divergent points of view became dominant. Environmentalists said, "Put it back the way it was," and the miners responded, "Let's grow some weeds and hide it." These views are not surprising as they represent rather obvious alternative responses, albeit at opposite ends of the decision spectrum. The former case has prevailed more often than the latter, as most state and federal legislation -- both proposed and passed -- has required drastic alteration of the post-mining landscape so that evidence of prior mining is largely obliterated. An exception to this has been in porphyry copper country where the infrequent abandonment of mines has given emphasis to the second philosophy -establishing vegetative cover on mine waste materials. Now, it should come as no revelation to most mining people that both of these approaches to mine reclamation suffer from serious drawbacks when applied to open pit copper mines. First, whereas waste dumps and tailings dams can be vegetated with some aesthetic benefit, the massive presence of copper mining operations remains very prominent. It is difficult to conceal an open pit copper mine. Second, returning open pit copper mines lands to their original topography and productivity is simply not a reasonable alternative.

Jan 1, 1976

By Raymond L. Jones

With the inauguration of the open pit operation in Bagdad, plans were formulated for a large scale leaching operation. Dump stockpiling was started almost immediately, but actual production was not initiated until the spring of 1961. Like all neophytes, we started something about which, on a commercial scale, we knew next to nothing, either dump preparation or leach procedure, and as a consequence, we are still paying the piper. True, we had been through an extensive laboratory pilot program, but it soon became apparent that there was considerably more to increasing solution volumes than simple multiplication. Had we initially possessed our present acumen, the Cyprus Bagdad plant could be operated more efficiently and at a better profit. During the past several years, the art of dump leaching of copper has improved in many ways, primarily because of the application of scientific principles gleaned from general mining practice. Rigid pH control and the use of atomic absorption techniques for rapid," accurate assaying have probably played a leading role in this respect, although we cannot overlook the other sophisticated electronic controls lending improvement to acid addition and pumping, better piping materials, and lastly, the more efficient use of our pregnant liquors. Thin too, the years of experience have given us a greater understanding of dump behavior in general; and, we can, to a greater extent, measure, predict, and avoid some of the idiosyncrasies inherent in every dump. However, it is my firm belief that we will still be confronted with unexplainable dump behavior as long as we are involved in leaching. We have found our dump to be a wonderful money bank, but one that is capable of yielding a wildly fluctuating profit.

Jan 1, 1975

By Robert E. Murray

The title of my paper, "A Company's Response to Federal Coal Leasing," brings to mind a picture of a dog chasing its tail. This is what the coal industry, has been doing since the Federal coal leasing moratorium went into effect in 1971. We've gone around in many circles, but we are only very slowly, if at all, getting closer to catching our tails, i.e., efficient, economical, and rational Federal coal leasing. My companies, The North American Coal Corporation and its four Subsidiaries, The Falkirk and Western Plains Mining Companies and The Coteau and Missouri Valley Properties Companies, together hold in excess of 4.5 billion tons of lignite reserves in North Dakota. Some of our North Dakota properties are substantially interspersed with Federal coal, with the government holding title to the minerals in every other section. This checkerboard pattern of Federal ownership has made it difficult to develop and market some of our reserves, and, as a result, it has become imperative that we be familiar with and active in the Federal Coal Leasing Program.

Jan 1, 1982

By B. E. Davis

A fundamental study of the mechanisms involved in the conditioning of coarse Florida phosphate has led to some interesting discoveries. Studies by the Bureau of Mines have shown that conditioning time and mixing intensity greatly affect the grades and recoveries of the phosphate minerals and quartz in the rougher concentrate. In particular, as the conditioning time or mixing intensity increased, the phosphate recovery remained constant while the amount of quartz floated decreased. This phenomenon is contrary to conventional wisdom and could lead to a more efficient coarse flotation circuit.

Jan 1, 1993

By W. W. Atkinson

This paper describes some concepts developed in a geologic data recording system at the Victoria, Nevada breccia pipe-skarn copper mine. The recording system is not fundamentally new, but represents expansion of earlier ideas. The paper is based on the philosophy that a high quality geologic data base is necessary and that it should be complete, clear, standardized, neat, quantitative, and readily useable. It may be multi-colored or simply black and white. Graphic, descriptive and quantitative recording of data is essential. A format for core logging is presented and discussed and as well as a multiple overlay system for recording data gathered in surface mapping.

Jan 1, 1983

By James L. Coburn

Leaching is defined as a form of extraction in which a valuable constituent is removed from a solid body by mass transfer to a solution which, for the purpose of this discussion, is considered to be an aqueous medium. Historically, leaching has been applied to the recovery and purification of many elements. This paper, however, is directed toward the recovery of copper, uranium, vanadium, and precious metals included in the following systems: 1. The leaching of copper minerals, sulfides and oxides, by acid or by ammoniacal leach solutions with or without an oxidant. 2. The leaching of gold and silver, either native metals or as minerals by an oxygen-containing alkaline cyanide solution. 3. The solubilization of certain uranium and vanadium minerals by oxygen or oxidant-bearing lixiviants. Many other systems of this general type exist, but from a production standpoint, these three systems account for most of the major values recovered by leaching.

Jan 1, 1975

By William A. Vogely, Robert T. Deacon, Walter J. Mead

Oil and gas together are the most important energy sources consumed in the United States. In 1983, 67% of total energy consumption was represented by these two resources (43% was oil and 25% natural gas), while coal accounted for only 23% of U.S. energy use. All other sources (hydroelectric, nuclear, geothermal, wood and other waste products) accounted for only 10% (U.S. Department of Energy, 1983, p. 1). In this chapter we address the issue of regulation in the oil and natural gas sectors of the U.S. energy industry. In addition, we analyze the cartel characteristics of the Organization of Petroleum Exporting Countries (OPEC). If OPEC is an effective cartel, then U.S. oil as well as substitute energy prices, production, and consumption will be affected by cartel action. Further, as the nation learned in the 1970s, major changes in oil prices produced major disturbances in other sectors of the U.S. and world economies. Consequently, it is important to determine whether the roughly ten-fold increase in nominal prices that occurred in the 1970s was the result of cartel action, the result of normal economic forces adjusting to the fact that the world was running out of cheap oil, or some combination of the two. Furthermore, the presence of OPEC- associated oil price increases is related to regulations that were imposed on the energy sector during the decade of the 70s. THE RATIONALE FOR GOVERNMENT INTERVENTION Economists have traditionally judged the state of an economy to be efficient if it is impossible to improve the welfare of any one member of society without harming someone else. Any economy that satisfies this condition is said to be Pareto efficient, after the Italian economist Vilfredo Pareto who first gave rigorous attention to such questions (see Chapter 4.10). It is easy to see why an economy that fails to satisfy this condition could not be efficient; by definition, it would be possible to alter the allocation of resources in a way that improves everyone's welfare.' Much of the appeal of this weak efficiency criterion is that it avoids comparisons of levels of well being among different individuals. The cost of such generality, however, is that in any given economic system a wide array of different Pareto efficient states will typically be attainable. In the simple Robinson Cursoe economy of the undergraduate textbook, for example, efficiency could just as easily be attained in the case where most of the island's resources are owned by Friday as in the case where they are under Crusoe's control. However, the distribution of welfare among the two inhabitants would obviously be quite different in the two situations. Such equity issues cannot be settled on objective or scientific grounds. To decide which distribution of welfare is socially "best" an explicit value judgment is needed. It is useful to keep in mind the preceding distinction between efficiency and equity issues when analyzing the role of government in a market economy. Decentralized market processes will not necessarily result in a distribution of welfare that society considers just. For this reason a potential role for government lies in the redistribution of income among individuals. In some circumstances, however, market pro-

Jan 1, 1985

By J. Partyka

Respirable dust produced during blasting operations in underground mines exhibits both diffusion and convection properties of the airflow. However, the application of the mathematical model presently used to calculate the change in time in the concentration of blasting pollutants is mostly limited to a single drift and cannot be easily utilized for blasts taking place in stopes. This paper discusses an analytical solution based on considerations that enable us to reliably identify the initial condition. Such an approach may be used for any blasting area regardless of its position, its size, or the ventilation system in use during blasting. In addition, a test procedure using field data is established to determined those parameters not measured directly. As well, equations are derived to find the diffusion coefficient, and the position and size of a dust source from the field data. Mathematical considerations The convection-diffusion problem, for a one-dimensional case, is described by the following partial differential equation (PDE): ct. = Dcxx - Vcx + source - sink(1) where C = the concentration of a pollutant T = time V = the mean air velocity in x-direction D = the diffusion coefficient X = distance away from the pollutant source source = any additional pollutant source specified by an initial value problem sink = decay of a pollutant inside the region specified by the boundary conditions. Respirable dust produced during blasting is best considered as an initial value problem (IVP). To derive a mathematical model, the following assumptions are made: •At time zero (t = 0), the dust source is at point x = 0 of an infinite drift. •The problem is considered a one-dimensional case. •The mean velocity of air and the diffusion coefficient are constant. •There is no source or sink of dust other than specified at point x = 0 and time t = 0. We have to solve the following problem [PDE ct=Dcxx-Vcx-m<x...m;0<t<m(2)] ICc(x,0)=f(x)t=0, the initial condition Where c = dust concentration in mg/m3 V= the average mean velocity in a drift in m/s t= time in s D= the diffusion coefficient in m2 /S x = distance coordinate in m. We observe that in problem (2), we have moved the boundaries to[ -m and +m] in order to have an initial-value problem. We introduce new coordinates, s = t and z =x - Vt. To rewrite the PDE in terms of (z, s), we use the chain rule ct = czzt + csst = -Vcz + cs cx = czzx = cz cxx = (cz)x = czz. We now substitute our computed ct, cx. and cxx into the PDE to get new IVP in terms of z and s :

Jan 1, 1991

By W. J. Roberds

A formal and explicit yet cost-effective approach is proposed to ensure that decisions made during mine development are optimum (with respect to their ultimate consequences) as well as defensible. This risk management approach is based on probabilistic risk assessment and established decision analysis techniques, and appropriately considers the relationships among various mine development decisions, tradeoffs among consequences, the uncertainty in predicting consequences, and the benefits of flexibility to respond to changed conditions.

Jan 1, 1992

By Otto Schumacher

Shortcut methods are commonly employed for estimating mining costs for prefeasibility studies. Most of these methods, however, are suitable for earliest stage studies or for internal discussion purposes only. The experts at InfoMine?s CostMine division recommend that any cost estimate completed for purposes of significant decisionmaking or for compliance with Canada?s NI 43-101 requirements be completed using a determinative itemized method. The same basic principles apply for an early stage, intermediate stage, or advanced stage estimate. The only difference is in the level of detail and effort employed. ? Based on the results of a completed resource estimate, an itemized cost estimate begins with development of a conceptual mine plan. Using a surface mine as an example, four elements are crucial no matter what level of study is initiated. Basic geometry of the ore deposit and waste material, with a determination of the expected ratio of waste to ore, a reasonable pit slope angle, possibly requiring the completion of geotechnical studies to predict the waste-to-ore ratio with certainty. ? Determination of the assumed ore and waste production rates. ? Locations of all ore stockpiles and waste dumps. ? Segmental haulage distances and gradients for ore and waste.

Oct 1, 2013

By Harry Teicher

The subject of Specialty Silica Products could encompass a broad range of materials, some of which would be familiar to members of the Society of Mining Engineers. With the concurrence of your chairman, I have chosen to limit my remarks to synthetic materials, not including such siliceous materials as diatomaceous earth, asbestos, quartz and clays. For purposes of discussion, I have classified Specialty Silica Products into two groups -- powders and liquids -- which I will discuss in that order and which are categorized in Figure 1. The synthetic silica powders are amorphous to x-rays and are manufactured by various processes resulting in products of a wide range of physical and chemical properties, as well as functional performance and applications. Applications or functional properties are generally dependent upon such physical properties as micron-sized particles exhibiting large surface areas per unit weight and low apparent bulk density. Their presence in various systems modify surface properties. As summarized in Figure 2, they act as viscosity modifiers, flow conditioning agents, anti-slip agents, anti-blocking agents, flatting agents in surface coatings, reinforcing agents in polymers such as silicone rubber and numerous other applications. Although the various types of silicas exhibit various levels of functional performance in these end uses, they are not usually equally effective as direct replacements and I will briefly discuss the various types of materials.

Jan 1, 1974

By R. J. Nankee

Recent on-going efforts to develop commercial coal cleaning beneficiation processes using chlorinated solvents-as the separating media will be described. True heavy media separations were performed on raw coal feedstocks, including Pennsylvania anthracite; Western, Eastern, and Midwestern bituminous; and lignite coals. Separation techniques included bath-type devices, cyclones, and liquid/liquid partitioning. Details on separation devices, removal of solvent, and recovery and recycling of solvent will be discussed. Projected costs of full-scale plants will be given for various coal sizes. A number of the coals evaluated are good candidates for beneficiation using chlorinated solvents. Coal beneficiation is desirable to provide needed coal quality. These needs include low ash fuels for coal water slurries and low sulfur fuels to meet emission regulations. In October of 1985, a paper, "Chlorinated Solvents for Coal Beneficiating"&apos; was presented at the fall meeting of SME-AIME at Albuquerque, New Mexico. It reported the results obtained from various coals as feedstocks and of the separations using chlorinated solvents. These beneficiation results depended on true heavy media gravity and liquid/liquid partitioning separations. This paper will include detailed descriptions of the liquid/liquid partitioning process used in "Dow&apos;s Advanced Coal Cleaning Technology?2 and of the "Dow Solvent Recovery Technology.?3

Jan 1, 1987

By D. Gill, R. Burgess, B. Kyslinger

"There is always a demand in the mining industry to improve the safety and efficiency of roof bolting. Since 2008, Anglo American and Fletcher® have been working together to develop a new roof bolter concept that is safer and more ergonomic while maintaining current production rates. The recognized types of machines currently used in South Africa are always under constant review for improvement; however, there are limitations to the current design. The majority of the machines in South Africa are the “Man in Position” roof bolters. There are currently over 200 of these roof bolters in South Africa, with the bulk of the machines being twin-boom units. When operated correctly, these machines are safe, versatile, reliable and productive. However, with the operators located close to the drilling and bolting operations, they can be exposed to operational hazards. In addition, the major amount of material handling can be quite difficult on an operator. Anglo American, with a desire to improve safety, approached Fletcher to develop a remote style machine with simplified controls that maintained the productivity of the twin-boom machines. After several prototypes, the current model was developed. The chassis was designed for better operator comfort. A dual mast drill module was implemented to reduce the total time to bolt a cut. A remote operator’s station was incorporated to remove the operator from the front of the machine. The design was all about producing a safe and ergonomic machine from front to rear. This paper will explain the evolution and technological advancements from earlier prototypes to the current production machine. INTRODUCTION With mining, especially coal extraction, comes the necessity of supporting the roof. Since the 1950’s, the primary method for roof support has been the use of roof bolts. Roof bolting is considered one of the most hazardous jobs in underground coal mining. In 2004, there were 3,405 injuries reported to MSHA (Mine Safety and Health Administration). Of those injuries, 17 percent were associated with bolting machines (593 injuries). The majority of the injuries resulted from rock falling from supported roof. However, injuries involving a part of the body being struck by, or caught between, during bolting and drilling occurred with relatively high frequency (Burgess and Steiner). Roof drilling and bolt installation is labor intensive and repetitive. These labor intensive and repetitive requirements can lead to cumulative trauma. Operators are expected to perform a considerable amount of lifting, carrying, bending, reaching and stretching. Back and shoulders become sore from bending and twisting to install bolts or lift and position drill steels, wrenches and bolts. Confined operator spaces also contribute to difficult and awkward working positions for the operators (Cornelius and Turin)."

Jan 1, 2017

By Raymond Mancha

"Conventional" coal dryers really do not exist. What we really mean to say is that there are many and varied kinds of coal dryers -- and the "air handling problem" is really the only portion of it which has been approached for solution by conventional methods. It now appears that these conventional methods need supplementing by some new, relatively unconventional apparatus. In order to approach this matter with mutual understanding, here is a quick survey of the coal drying art. Figure #1 shows a McNally Pittsburgh Pulso Dryer, In the McNally Pulso Dryer, the coal is fed-onto the screen by a rotary feeder assuring even distribution of the coal. As the coal travels forward due to the action of the screen, it is subjected to a controlled pulsating flow of hot gases. T ese originate below the deck and are directed up through the moving bed of coal. Fines sifting through the deck are dried in the hopper below the screen as they fall through the hot gases to an evacuation screw. The coal remaining on the screen is dried to the desired degree when it reaches the discharge end. At this point, it is directed down into the evacuation screw to combine with the fines, or it may be discharged as a separate product. As the coal travel down the screen, it is subjected to intermittent upward currents of hot gases. These first distend the bed allowing the gases to come into intimate contact with the coal particles for rapid and efficient heat transfer. Then, as the flow of gas is cut off, the bed settles and the extreme fines sift through the screen preventing their being carried away into the exhaust system.

Jan 1, 1958

By Ernesto Maldonado, Jesus Romero Benitez, Zach Agioutantis

Numerous researchers worldwide have investigated the prediction of ground movements due to underground coal mining utilizing different analytical, empirical, and numerical models. These studies have primarily focused on the development of prediction methodologies for either flat or gently dipping seams under variable topography, and only a few studies are available that have investigated the prediction of ground movements over inclined seams. Although most inclined coal seams are in China, India, and other countries worldwide, a few inclined coal seams (with a dip of 10 degrees or greater) are also present in the US. Currently, the prediction of ground movements for inclined coal seams using empirical methods utilizes the same methodology for horizontal seams. It consists of dividing the inclined seam into horizontal segments, calculating deformations due to each segment, and superimposing the calculation results. This paper presents a new tool that provides a methodology for modeling subsidence under inclined seam conditions. Examples based on subsidence measurements available in the literature are presented. The goal is to implement this methodology into the Surface Deformation Prediction System (SDPS).

Jun 25, 2024

By Werner A. Ruemmele

Eisenhower Memorial Tunnel, called Straight Creek Tunnel during construction is located 60 miles west of Denver, Colorado at 11, 160 ft. elevation. It is 8, 510 feet long, and carries two lanes of 1-70 traffic under the Continental Divide. This paper describes improvements and changes made in construction methods for utilities, concrete lining, ceiling, wall covering and paving to allow maximum offsite fabrication and activity overlap resulting in a one-year faster completion for traffic. The substantial changes proposed on a design-and-construct basis by the contractor and put into effect after State approval were: 1. Substitution of ductile iron and thick-wall P.V. C. pipes for clay pipes allowing placement and operation before hole-thru. 2. Outside pre-assembly of large rebar mats, using a novel tension-splice with cable clamps. 3. Arch concrete placement method modified to make 4, 322 ft. of lining in 10 weeks possible. 4. Safety barriers precast and epoxy coated offsite instead of cast-in-place and tile faced. 5. Prestressed hollow ceiling slabs with porcelainenamel coated steel sheets assembled offsite, instead of in-place glazed tile and in-place cast concrete ceiling. 6. Glazed tile wall panels 8 ft. long by 11 ft. high assembled off site and erected using vacuum pad mounted on special lift. 7. Asphalt paving while other work proceeded, instead of reinforced concrete slab and asphalt overlay. Work started in January 1968, but advance came to a one-year standstill for major structural redesign and negotiations of a new agreement during 1970. Using multiple drift construction followed by top-heading and bench excavation, it then progressed to hole-thru in July 1972. As a result of art 18-month overlap of activities the tunnel was opened for traffic only eight months later in March 1973. Gibbons and Reed Company of Salt Lake City, Utah sponsored the joint Venture of Al Johnson-Gibbons and Reed-Western Paving-Kemper during 1971, 1972, and 1973. The tunnel was the subject of a previous paper delivered at the RETC &apos;72 in Chicago by R. C. Hopper, T. A. Lang, and A. A. Mathews, describing geology, unusually severe structural loading and multiple-drift tunnel excavation.

Jan 1, 1974

By A. S. Paschoa, A. W. Nóbrega

INTRODUCTION There are now over twenty years since the radiological characteristics of the brazilian regions of Araxá, Tapira and Barreiros, three locations adjacent to each other, in the state of Minas Gerais, Brazil, started being surveyed by investigators from the Instituto de Biofísica da Universidade Federal do Rio de Janeiro (IB/UFRJ), Pontifícia Universidade Católica do Rio de Janeiro (PUC/RJ), and New York University (NYU) (Roser and Cullen, 1958; Cullen et al, 1980). The importance of the Araxá apatite – Ca5,(P04)3(OH, F, Cl) - and pyrochlore - NaCaNB206F - for the production of large quantities of fertilizers and niobium was early recognized (Roser and Cullen, 1958). Interesting data have been gathered and published throughout the years on the contents of naturally occurring radionuclides in geologic materials, soils, grass, foods and waters of the Araxá region (Eisenbud, et al., 1964; Penna Franca, et al., 1965a, b; Roser et al., 1966; Penna Franca et al., 1970; Cullen, 1977; Penna Franca, 1977; Cullen and Paschoa, 1978; and Cullen et al., 1980). The radioactivity of the Araxá region is associated with mineral deposits of niobium rich pyrochlore and phosphate rich apatite. There are in this region mineral ores with 3 to 5% pyrochlore with 2 to 2.5% Th as Th02 and 50 to 150 ppm U308 in the matrix, while the apatite deposits contain up to 150 ppm U308 and a thorium concentration similar to that of the pyrochlore deposits (Paschoa and Palacios, 1981). As an indication of the high thorium content of the Araxá soils the 228Ra and 224Ra activity concentrations were reported to range from 10.6±0.2 to 62.4±0.7 pCi228Ra/g soil in 7 samples and 2.1±0.1 to 104±1 pCi224Ra/g soil in 19 samples (Cullen, et al., 1966). The uptake of radium isotopes by edible roots vegatables and fruits growing in the soils of the Araxá region can be illustrated by the data listed in Table I. The biological availability of natural radium isotopes in some segments of the Araxá soil allows a large variation in the 228Ra, 224Ra and 226Ra concentrations in vegetables and edible roots, as can be seen in Table I. This fact makes quite difficult a quantitative local assessment of the radiological implications of mining the Araxá mineral deposits of pyrochlore and apatite for production of niobium and phosphate fertilizers, respectively; since one cannot easily separate the naturally occurring from the technogically enhanced radionuclide contents of foods. The position of the city of Araxá inside the contour of the state of Minas Gerais appears in the upper part of Figure 1, which shows the outlined map of Brazil with the positions of the cities Brasilia and Rio de Janeiro also indicated. The lower part of Figure 1 is a representation of the Araxá region in an expanded scale, which indicates the locations of the pyrochlore and apatite deposits in relation to the city of Araxá, as well as the nearby hydrographic basins. The distance between the city of Araxá and the pyrochlore deposit is about 8 km, and between the pyrochlore and apatite deposits is 4 km. This paper deals tentatively with the radiological implications of the industrial operations taking place in the Araxá region for the exploration of the pyrochlore and apatite deposits. However, one must bear in mind, firstly, that the radiological implications of these industrial activities are by far too complex to be covered adequately by the limited amount of data to be presented in this paper, and secondly, that such implications cannot be considered of local character only. INDUSTRIAL OPERATIONS The commercial exploration of the Araxá deposits of pyrochlore and apatite started only few years ago, motivated by the increasing demand of niobium and phosphate fertilizers in Brazil and the world. As a consequence of the industrial operations in Araxá, a redistribution of the uranium, thorium, and radium originally present in the local deposits of pyrochlore and apatite started occurring in the seventies, with possible radiological implications for the Araxá region and its immediate surroundings, not to mention the destinations of the end products of such industrial operations. A literature review on the radioactivity associated with the extration industries of selected minerals was made by the USEPA (Bliss, 1978). The low level radioactive wastes of the industries for copper ore mining and rare metals processing have been object of particular attention (Fitzgerald, Jr., 1976; Eng, et al., 1979), but the short and long term implications of the radioactivity associated with the niobium industry were also subjects of concern (Knight and Makepeace, 1978). Recently, high 232Th and 226Ra concentrations in samples from the tin mining industry in West Malaysia were reported (Hu et al., 1981). A great deal of attention has been dedicated to the implications of the redistribution of radionuclides originally present in the mineral ores used by the phosphate fertilizer industry (Moore, 1967; Menzel, 1968; Spalding and Sackett, 1972; Eisenbud, 1973; Guimond and Windham, 1975; Guimond, 1976; Roessler,

Jan 1, 1981

By F. Calizaya

This study summarizes the ventilation requirements for a highly mechanized P.T.Freeport Indonesia&apos;s underground mine operation in Irian Jaya, Indonesia. The Deep Ore Zone (DOZ) is a copper-gold deposit being developed underneath the current Intermediate Ore Zone (IOZ) mine. One of company&apos;s current plans is to prepare this mine for a steady oreflow of 25,000 tpd by year 2003. This study includes the estimation of airflow requirements for various mining activities, the design of major intakes and returns, the determination of airway resistances and specifications of fan duties. It also includes the results of air pressure/quantity measurements in existing airways and the standards stated by the current Indonesian mining law.

Jan 1, 1998

By William H. Langer

U.S. Geological Survey (USGS) recently initiated the Front Range Infrastructure Resources Project. This is a multidisciplinary study along the Rocky Mountain Front Range from Pueblo, Colorado, to Cheyenne, Wyoming, and is designed to collect, compile, and analyze new and existing data on natural aggregate (stone, sand, and gravel), as well as water, and energy resources. To identify aggregate resources in the Front Range, a 1:500,000-scale reconnaissance map showing locations and quality of both bedrock and surficial sources of natural aggregate in the Front Range urban corridor was prepared by processing the digital geologic maps of Colorado and Wyoming. The first step of the process was to identify map units as either bedrock or unconsolidated material. Bedrock was classified according to type (i.e., limestone, granite, gneiss, etc.), which in turn was classified based on the suitability of the bedrock for use as crushed stone. Unconsolidated materials were classified according to relative age, with the older, more weathered materials being defined as less suitable for use as aggregate than younger materials. As a spin-off from the Front Range Project, the techniques developed for analyzing the Front Range geology have been modified and expanded to include all of Colorado and New Mexico. More detailed digital aggregate maps (1:24,000 scale) are being prepared in collaboration with the Colorado Geological Survey (CGS). Maps from the CGS "Atlas of Sand, Gravel and Quarry Aggregate Resources, Colorado Front Range Counties" show the distribution of potential resources of sand and gravel and provide general information about the physical properties of the resources. These maps are being digitized and merged into a single Geographic Information System (GIS) data base. In addition, the project is adding more specific information to the maps about deposit thickness, volume, and quality. This additional information is being obtained through field-characterization studies and modeling activities. The GIs data base can be displayed and queried using off-the-shelf software such as ArcInfo?, ArcView?, and Map Professional?. In addition, the USGS is developing a decision-support system to assist users in analyzing various land-use options on resource availability.

Jan 1, 1999