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By Osvaldo A. Bascur

Standards and technology for bringing information to the desktop have greatly evolved in recent years. The benefits to be realized depend on how these new tools are embraced at the performer level. A key operating challenge is to ensure cooperative effort is geared towards the most efficient achievement of identified operating and corporate objectives. Presentation, application and database layers are emerging in successful client/server applications, the three-tier architecture.

Jan 1, 1996

By Saied S. Navid, Michael A. Piepenburg, Richard F. Escandon, Robert C. Lindsay

INTRODUCTION Phase I of the Los Angeles Metro Rail Project, known as MOS-1 (Minimum Operable Segment-1), is the first phase of the 27 km± (17 mi) subway starter line. MOS-1 is currently under construction and involves approximately 6.4 km (4.4 mi) of subway, five stations, yards and shops routed through the downtown area of Los Angeles. The project will form the initial heavy rail backbone of a more extensive light and heavy rail transit system planned for the greater Los Angeles area in the future. Construction Contract A-171 is one of 4 tunnel contracts within MOS-1 and involves construction of twin tunnels running from the downtown metropolitan area west to MacArthur Park. The heavily populated and developed downtown area, potentially gassy ground conditions, and the possibility of undocumented abandoned oil wells in seismically active southern California made the design and construction of Contract A-171 a uniquely interesting project. This paper summarizes the construction history to date (December, 1988) including design geotechnical considerations, tunnel support design, as-built geologic conditions, shield tunneling performance through soft ground, and ground response. The findings presented herein may aid in the design and construction

Jan 1, 1989

By A. D. Trippel

The Cripple Creek Mining district is located in Teller County, Colorado, 30 km west of Colorado Springs and 9 km southwest of Pikes Peak (Fig. 1). Since its discovery in 1891, the district has produced almost 21 million tr oz of gold (Gott et al., 1967), most of which has been from high-grade vein deposits. Globe Hill is located in the northern part of the district (Fig. 2). Production from its summit has yielded over 100,000 tr oz of gold. Early production was concentrated along high-grade veins and fault structures, but emphasis was soon placed on the extensive, low-grade (0.0X oz/t), breccia-hosted mineralization. From 1977 to 1981 Newport Minerals, Inc., a subsidiary of Gold Resources, Inc., mined 680,000 t of low-grade gold ore from the Globe Hill pit (Fig. 3) and production is expected to resume in 1986. These strongly-altered and -oxidized breccias are amenable to bulk-mining methods, and thus similar deposits are currently being sought elsewhere in the district. Numerous publications and reports discuss the breccia-hosted mineralization at Globe Hill. They include Cross and Penrose (1895); Argall (1905, 1908); Lindgren and Ransome (1906); Keener (1962); Peters (1982); Thompson, Trippel, and Dwelley (1985); and Trippel (1985). This preprint is a summary of the recently-completed research documented by Trippel (1985).

Jan 1, 1986

By O. Tranbarger

In aging tunnels, wall and roof deterioration can eventually result in defects that must be detected and repaired to maintain safe structural conditions. In investigating tunnel defect conditions, a specialized FM radar system was developed with a programmable VHF and UHF operating sweep range for optimizing the penetration and measurement capabilities. The new FM radar technology was tested in two aging brick-lined tunnels in New York City. Test results showed that FM radar signals could penetrate eight courses of water-saturated brick and that the original steel liner outside the tunnel walls was intact.

Jan 1, 1985

By W. Gibson Jaworek

It has become apparent in recent years to everyone intimately concerned with the future of the American fuels industries that the growth in demand for energy has become a topic receiving considerable attention, and that investigators are leaning more and more toward a mathematical approach to deduce what pattern that growth will follow. Though coal has been included by necessity In all-studies of future energy markets, it has not been the subject of mathematical analysis or description as frequently as has been total energy or some of the other fuels, particularly petroleum, It is the intent in this particular paper, to subject bituminous coal consumption to a preliminary mathematical scrutiny which can lead to a more logical estimation of the general level of bituminous coal consumption for the next decade, as well as formulating an approach toward describing how coal consumption may vary as the result of the annual variations in activity in the United States, economy, The approach utilized is more sophisticated than the mere projection of the historical trend of bituminous coal consumption. Such a projection would lead to a continuation of the recent decline, indicating that coal consumption would reach zero some thirty years from now. On the other hand, the mathematical analysis described here is a relatively simple, straightforward approach and- is not intended to represent the-ultimate in mathematical economic analysis as now practiced, It is hoped that this will contribute to our knowledge of bituminous coal markets. Even more, it is hoped that it will help arouse a greater interestin utilizing mathematical and statistical analysis when studying the bituminous coal industry. - Since this is a preliminary study, comments and criticisms are anticipated.

Jan 1, 1960

By D. Dolinar, T. P. Mucho

Horizontal stresses are caused by global platetectonic forces. During 1995 alone they were largely responsible for the closing of two longwall mines in the United States. This paper presents six case histories from Pennsylvania, West Virginia, Kentucky and Alabama. In each case, a mine encountered roof falls or difficult ground conditions at the headgate caused by horizontal-stress concentrations. The problems are detailed, and the control measures adopted are described. In most cases, nearby longwall panels without stress concentrations were trouble free. The paper also discusses detailed measurements that were made at two adjacent Pennsylvania longwalls. One headgate was oriented to avoid a horizontal-stress concentration, and the other was not. Eliminating the stress concentration dramatically reduced roof support loads and roof deformation. The paper concludes that proper panel orientation and sequence is the key to maintaining headgate ground control. The optimum orientation is not parallel to the maximum horizontal stress, as previously thought, but rather it is 20o in the stress shadow of the gob. Other stress-control techniques, including artificial support, are briefly discussed

Jan 1, 1999

By Richard P. Curtin, Madan M. Singh, Francis S. Kendorski

INTRODUCTION The use of roof and rock bolts to reinforce the strata is an established method of rock support in both underground and surface excavations. However, the need to drill a hole, extract the drill-rods, and then place the bolt is time-consuming and costly. This becomes even more significant if the bolting is repetitive and extensive as in coal mining. Though the main thrust of this development was directed towards coal mining, the basic concepts are also widely applicable to all excavations. The authors, therefore, feel that this innovation should be of interest in rapid excavation and in tunneling. In the case of coal mining, it has been established from past statistics that the roof-bolting operation is the most hazardous activity. This is primarily because of the operator being exposed to unsupported ground. It is evident that remote installation of roof bolts would markedly improve the safety of the operation, if accomplished more readily with self-drilling bolts rather than the conventional two-step variety operation. Thus, in addition to increasing productivity, this development can be considered to be a milestone towards further improvements. The objective of this program was to establish the technical and economic feasibility of self-drilling roof bolts for use in coal mines. It might be clarified at the outset that this work was, therefore, directed primarily at showing that workable self-drilling bolts with less cost can be developed, which could be effectively used in mines. It was not to fabricate a production model bolt.

Jan 1, 1979

By Betty L. Gibbs

Before the first shovelful of dirt is removed from a developing mining property, a wide range of data must be collected, organized and analyzed. Among the key steps in this process are: • Visualization of the deposit from drill hole data and geologic interpretation, using all available information, including surface geology, geochemistry and geophysics. • Drawing of vertical and horizontal sections. • Construction of a 3D solid model of the deposit. • Contouring of deposit outlines and geological structure until the model represents best estimate of reality. • Estimation of grade and quality distribution. • Calculation of reserves. • Examination of possible mining methods. • Determination of economic feasibility. Many techniques are available to aid in this process of mine project feasibility analysis, from quick pencil calculations to sophisticated computer methods. However, time races faster in the complex modem business world than it did 50 years ago. Tried and true pencil methods take too much time. Opportunity may pass a mine developer by while a property is still in the first stages of analysis. In the days of hand techniques, initial analysis of the economic feasibility of a mining project usually stopped with reserve calculations and broad mine planning. Further planning was not done or was done only for the short term. Manual techniques require too much time and manpower to evaluate a longterm mining program. Mining-industry recognition of computer utility has increased. Most companies now use computers in technical applications and could not conceive of working without them. Building initial computer models of a deposit may take nearly as long as hand techniques. But the payback comes when changes are needed and a variety of mine plans are quickly tested.

Jan 1, 1990

By K. T. Valsaraj

The separation process called solvent sublation for the removal of two hydrophobic compounds (penta-and tri-chlorophenols) from the aqueous phase is discussed. A steady state mathematical model for the process is discussed. The process was conducted in a continuous countercurrent mode. The underlying mechanisms, theory and experimental details on the effects of process variables on removal efficiency are reported.

Jan 1, 1992

By G. M. L. Robinson

Mineral Processing Wastes, as defined by the Environmental Protection Agency (EPA), has determined that most of the mine wastes will be regulated pursuant to subtitle D (Solid Waste Regulations) of the Solid Waste Disposal Act while specific mine waste categories will be regulated within the framework of the Toxic Substance Control Act. Though EPA's determination currently relieves the industry of the regulatory constraints mandated by the Resource Conservation and Recovery Act (Hazardous Waste Regulations) Subtitle C regulatory framework; the industry is not granted immunity from historical or current environmental regulations related to listed or characteristically hazardous or solid wastes. Because of the current regulatory trends and the need to implement cost effective remediation alternatives; advanced currently available on-site remediation technologies are available to minimize, reduce, contain or prevent environmental impacts related to mining and processing activities. In light of industry technical needs, an overview of the research and commercially available remediation technologies will be discussed and a brief discussion of the strengths and weakness of each technology will be presented. Technologies to be discussed includes stabilization, solidification, soil wash, soil flush, thermal distillation, pump and treat, metal extraction, centrifuges, filter presses, bioremediation, and incineration.

Jan 1, 1992

By David X. Zhang

This paper describes the results of using shear flocculation and flotation known as aggregative flotation technique for the enrichment of coal-derived char produced from mild gasification process. Aggregative flotation is a separation process which involves the use of suitable aggregating liquid under the action of high shear forces to render hydrophobic surface of coal-derived char particles to aggregate in an aqueous slurry. The fine carbonaceous particles are aggregated into larger floes while the impurities remain hydrophilic. In subsequent flotation process, the char aggregates are then separated from mineral matters by aeration in the flotation cell. The floatability of char aggregates and removal of mineral matters from chars are studied in a lab scale flotation column cell. The effect of various operating parameters on the aggregative flotation responses is presented. Emulsification of aggregating liquid using high intensity agitation and ultrasonic energy provides excellent aggregating liquid dispersion and increases selectivity for char aggregation. In subsequent flotation process, it results in significantly increasing the flotation rate of char aggregates. The microscopic examinations of bubble attachment to coal-derived char particles under various aggregating liquid dispersion levels were conducted by induction time measurement. The distributions of hydrophobicity of char particles and char aggregates prepared under various aggregating liquid dispersion techniques were measured by film flotation. The char particles prepared under high intensity emulsification attach at significantly faster rates to air bubble and with lower mean critical wetting surface tension than that of char with direct aggregating liquid addition. An interrelationship of increasing in flotation rate/combustible recovery with decreasing in induction time, mean critical wetting surface tension and dispersion of hydrophobicity on the char particles and char aggregates were obtained.

Jan 1, 1992

By Philip-Mark Spanidis, Christos Roumpos, Francis Pavloudakis

This paper presents a quantitative research (QNR) methodology, collaboratively conducted with a group of mining experts, to assess the knowledge management (KM) landscape in the Greek mining industry. The methodology involves a framework for structured data collection using questionnaires, statistical analysis, discussion on critical methodological aspects, and interpretation of results focusing on key aspects of interest for designers of KM systems. The paper concludes by summarizing the methodology’s outcome and proposing perspectives for further research.

Aug 1, 2024

By D. R. Spears

The Bureau of Mines has investigated the fundamental aspects of shear-flocculation using a rapid, in-situ particle size analyzer. Silica was stirred in the presence of an aliphatic amine to determine the effects of collector coverage, stirring speed, and solids concentration on the kinetics of shear-flocculation. The results showed that shear-flocculation is a two-stage process. In the first stage, mean particle size increased rapidly in the first 1-2 min of reaction; in the second stage, an equilibrium was set up between the rate of floc growth and floc decay. Collector dosage affected the position of the equilibrium by altering the number of surface sites for particle-particle attachment. A minimum stirring speed was necessary for shear-flocculation to occur and was dependent on solids concentration and collector dosage. This speed was the minimum necessary for particles to overcome the electrostatic energy barrier which kept conditioned particles dispersed. Larger particles flocculated more rapidly. At very high stirring speeds, large flocs became unstable, resulting in a narrowed particle size distribution in the slurry.

Jan 1, 1993

By James S. Goff, Stephen J. Navin, Wesley W. Moulton

The White River Shale Oil Corporation (WRSOC), as agent for Phillips Petroleum Company, Sohio Shale Oil Company, and Sun Shale Oil Company, is developing a prototype oil shale facility on Federal Lease Tracts Ua and Ub, located in northeastern Utah and known as the White River Shale Project (WRSP). The Ralph M. Parsons Company (Parsons) has been retained as the design engineer/constructor for the project. This paper covers the successful pregrouting of the Bird's Nest Aquifer in conjunction with the sinking of a 9.2-m (30-ft)-diameter shaft and driving of a 3.89-m by 5.64-m (18.5-ft by 12.75-ft) decline. The Bird's Nest Aquifer derives its name from the ellipsidal solution cavities caused by leaching of random-size nacholite nodules. The sodium bicarbonate nodules occur as persistent bands within a matrix of siltstone and marlstone. The team, made up of the owner, engineer/contractor, and subcontractor successfully grouted the shaft down to an inflow of less than 0.06 lps (1 gmp) and the decline down to less than 0.12 lps (2 gpm) by injecting a total of 213.190 kg (470,000 lb) of Celtite Terraseal, 113,400 kg (250,000 lb) of limestone dust, and 41,730 kg (92,000 lb) of cement into the formation.

Jan 1, 1985

By Peter T. Chiang

A brief literature review on metal separations by ion exchange and solvent extraction of their thiocyanate complexes which are practiced in analytical chemistry as well as in industries was performed. Owing to the poor stability of free thiocyanic acid in acidic aqueous and organic media, technical and environmental problems which cause high thiocyanate consumptions often arise during the practice of the separation processes. This prompted the conducting of a second and more thorough literature review on the chemistry of thiocyanic acid. The objectives of this undertaking are to compile and interpret literature data on the physical properties and chemical reactions of thiocyanic acid, thus providing a clearer understanding of the causes of these problems and giving options as to how to minimize them. The best answer found for carrying out the separation processes is to keep the temperature, thiocyanic acid concentration and total acidity as low as practical.

Jan 1, 1984

By Cary Hirner, Tony Cicchetti, Daniel G. Cressman, Jeff F. Wallace, Prapan Dave, Malcolm Sheehan

The City of Toronto is currently undertaking the design of the Black Creek Sanitary Trunk Sewer Relief Project. The Project involves the design and construction of approximately 20 kilometers of tunnel through shale rock of the Georgian Bay Formation and soft ground soil consisting of glacial till, glaciolacustrine and glaciofluvial sand, silt and clay deposits. The 20 kilometer alignment has been split into four sections of tunnel (1) the 12.9 km, 3.0 meter diameter Keele Trunk Relief Sewer, (2) the 2.9 km, 1.5 meter diameter Keele Trunk Relief Sewer Microtunnel, (3) the 3.9 km, 1.8 meter diameter Jane Relief Sewer, and (4) the 0.5 km,1.5 meter diameter Combined Sewer Overflow Storage Tunnel. Additionally, one 40,000 m3 wet weather flow (WWF) storage tank and numerous WWF connection shafts are to be constructed and connected to the Keele Trunk Relief Sewer to pick up WWF from existing outfalls currently discharging to Black Creek. The anticipated cost of the project is approximately $600 million with construction of the Project’s Phase One Works, the Keele Trunk Relief Sewer and Jane Relief Sewer, scheduled to commence in 2025. This paper provides an overview of the project in terms of the anticipated geotechnical conditions, the scheme developed for design and construction of the tunnel system and the associated schedule and procurement strategy. The consideration for planning of the tunnel system, the risk-based analysis and decision-making process are presented and form the basis for selection of a precast tunnel lining support method in the rock and soft ground.

Jun 13, 2023

By W. E. Lamont

As part of its program to minimize mineral and metal needs, the Federal Bureau of Mines conducted investigations to determine the feasibility of producing foundry-sand-grade olivine concentrates from low-grade sources. Using a Bureau-patented attrition-grinding technique, concentrates meeting Steel Founder's Society of America (SFSA) specifications for loss on ignition (LOI) were prepared. Studies showed that green strengths and tensile strengths of the attrition-ground olivine were equivalent or superior to those of commercial materials. Metal-casting studies showed that molds of attrition-ground olivine produced better surface finishes. The improved surface finishes were attributed in part to increased grain sphericity.

Jan 1, 1977

By V. N. Kolesnikov

The gold-silver deposits of the northern Primorye region are located in the eastern part of the East Sikhote-Alin volcanic belt, where the belt overlaps the Kema island-arc terrain of the Aptian-Albian age. There have been four deposits and numerous mineralization points found in the NE-trending Kema metallogenic belt that is about 1000 km long and 100 km wide. The known mineralization is of epithermal type, controlled by faults, and concentrated in quartz, quartz-fluorite-adularia, and, less commonly, sulfide-quartz vein systems hosted by the Upper Cretaceous-Lower Tertiary volcanic rocks. The vein systems extend for hundreds meters along strike, varying from tens centimeters to 50-60 meters in width. They are surrounded by wide zones of low-temperature hydrothermal alteration containing some gold-silver mineralization for which the commercial value was not studied during the early exploration. The ore bodies contain from 1 to 50-80 ppm of Au and from 1 to 1000 ppm of Ag. Gold is native, associated with quartz, and represented by particles from tens of microns to 1 mm in size. Silver occurs in native form as a constituent of argentite, pyrargyrite, stephanite, and other sulfosalts. The test work carried out for three vein systems 20 years ago showed that gold might be easily and almost completely recovered from the ore by cyanide treatment. The paper describes the geology and mineralogy of the deposits, Salut and Primorskoye, that are the most studied properties of the Kema belt. It also presents the data available on disseminated gold-silver mineralization in stockworks, altered explosive breccias, and wide zones of low-temperature hydrothermal alteration. This mineralization should be explored for possible exploitation as large open-pit, heap-leach deposits.

Jan 1, 1998

By A. Bruynesteyn

The results of leaching experiments in columns simulating 80 and 200 ft deep cores through a leach dump are discussed, By equipping the columns with can precipitation plants, actual plant conditions could be duplicated. The results produced a better understanding of the physical and chemical limitations of the leaching process.

Jan 1, 1975

By V. Rajaram

The Metropolitan Water Reclamation District of Greater Chicago (MWRD) imposed a no-blasting specification (blasting is restricted to the construction shaft and shaft bottom or boot) on the Deep Tunnel project in 1988. This was prompted by numerous complaints from the residents in the vicinity of the project, and controversies experienced on previous projects from blasting the rock overlying the tunnel. This paper will describe the methods utilized by two major contractors who are driving 20 km (12.5 of tunnel along with drilling over 36 shafts under this restrictive specification. The impacts on design, construction, schedule, cost, and the environment are detailed.

Jan 1, 1991