Search Documents

By Henk E. Brassinga

In Rotterdam a number of underground parking facilities have been built and are under development in the inner city, and in the suburbs. These parking facilities are located at already densely built areas. The design of these constructions has to take into account the impact of the building activities and that of the final construction on the surroundings. In this paper some examples of the different building methods of newly realized underground parking facilities are described, and problems that occurred during the construction are pointed out. In the soil conditions as present in Rotterdam the cost effectiveness of underground facilities can be improved by deepening the parking facility, and at the same time reducing the surface area so that the total parking volume remains constant. In this way the total volume of the diaphragm walls and the costs of the project is reduced.

Jan 1, 2006

By Taehong Kim, Carl Pannuti, Nikolas Sokol, Walter Herrick

BACKGROUND This paper discusses work performed as part the rehabilitation of the gravity flow section of the New Croton Aqueduct (NCA) during an approximately two year period between 2004 and 2006. The goal of the project was to restore the gravity flow section of the NCA to optimal operating condition, extending the lifespan of this significant water supply for the New York City metropolitan area. Rehabilitation of the NCA was purposely scheduled before the completion of the new NCA Water Treatment Plant now under construction (Figure 1). The NCA is a 3.73 to 4.34 m (12.25 to 14.25 ft) diameter brick-lined circular andhorseshoe shaped water tunnel constructed between 1885 and 1891. The NCA conveys water for approximately 50 km (31 miles) by gravity and pressurized flow from the New Croton Reservoir in Westchester County, NY to distribution and reservoir points along its alignment, terminating at a distribution station at 135th Street and Convent Avenue in Manhattan, NY. Prominent features of the NCA include a large intake facility at New Croton Reservoir, 38.6 km (24 miles) of gravity flow horseshoe shaped aqueduct, 11.3 km (7 miles) of pressurized flow circular aqueduct, 2 siphons, and 36 open shafts and headhouse chambers which are used as sampling, access and blow-off locations. Until a partial inspection in 1982, the NCA had flowed continuously since its completion nearly 100 years prior. Flow tests have confirmed that the NCA can convey up to 12.7 m3/s (290 mgd) (Figure 2). Cover depths of NCA vary considerably, ranging from a few to hundreds of meters, typically of hard rock. Primarily mined using means conventional for the late1800s, construction of the NCA also employed cut and cover methods in several low-lying sections of the alignment, totaling approximately 1.6 km (1 mile). The NCA crosses through numerous lithologic changes, fault/shear zones and under several significant water bodies including the Pocantico, Saw Mill and Harlem Rivers and the Tarrytown Reservoir. The NCA passes under the Harlem River as a siphon at a depth of approximately 122 m (400 ft) below grade (Figure 3). Soon after construction the Aqueduct Commission Reports on the New Croton Aqueduct documented prominent defects such as large voids behind the lining. More recently, large-scale inspections of the gravity flow section performed during the 1990sand a 2004 inspection of portions of the pressurized sections of the NCA have revealed additional defects such as open and/or deteriorated masonry joints/cracks, leaks ranging from trickles to several liters per minute into and out of the NCA, missing bricks, formed openings, and in one place, a rupture through the liner with discernable

Jan 1, 2007

By W. N. Hoskins

This report covers the final results of a two-phase contract study conducted between July 1974 and October 1976. A comprehensive summary of the initial phase of the study is included. Phase I of the study involved the investigation and evaluation of all potential candidate underground systems for mining the deeper deposits of oil shale and associated minerals in the Piceance Creek basin of northwestern Colorado. Phase II called for the refinement and the detailed technical and economic analysis of the most promising system or systems, thus disclosed. Of the several systems initially investigated and evaluated, four Showed considerable merit for exploiting the deeper deposits: (1) chamber and pillar mining with spent shale backfill, (2) sublevel stoping with spent shale backfill, (3) sublevel stoping with full subsidence, and (4) block caving mining using LHD's. Final refinement and analysis of these four systems indicated their technical feasibility over at least part of the range of conditions expected in the deeper deposits. Their economic feasibility also was indicated under certain operating and market conditions. A variety of engineering, production, and cost information is provided on each of these systems.

Jan 1, 1976

Statistics on the imports of industrial minerals into the EECshow that the traded volume in 1987 is approximately 23 million tonnes.The following table documents the imported quantities on the most important industrial minerals.

Jan 1, 1989

By Alfred Weiss

Selecting a minicomputer is not unlike selecting a costly piece of mining equipment such as a truck, shovel, crusher, or conveyor belt system. A marked difference might lie in the frequency at which such selection takes place; another difference might be mine management's familiarity with mining equipment vis a vis a minicomputer. These basic differences might prompt a mining company to seek the aid of a consultant when selecting a minicomputer system. Advantages and Disadvantages The fundamental advantage of employing an independent consultant is that it provides management with a source of knowledge and breadth of experience not readily available within the organization. If the consultant has a minerals background, such knowledge and experience are further enhanced by actual experience in exploration, mining, and mineral processing. If the consultant has worked within a mining company, such hands-on experience is supplemented with a meaningful understanding of the client's business; this facilitates communication between the consultant and members of the client organization. The consultant has been, so to speak, "in the client's shoes." There are several other advantages. Since computer systems cut across organizational boundaries, the independent consultant may be able to move within the organization more easily than an inside staff person to collect necessary information. Also, detachment from any manufacturer should provide the client with an objectivity and a set of recommendations as near optimal as feasible. The principal disadvantages lie in the area of continuity and accountability. Once the consultant's report has been submitted and his recommendations implemented, a discontinuity might occur. Also, if implementation does not provide the desired results, the consultant might not be available to correct the situation or account for actions taken. Proper selection of consultant services, relative to kind and duration, and the consultant's method of operation, will often prevent many of these aftereffects. Services Offered The professional consultant can help a client: •Define and summarize information systems technology* needs; • Evaluate alternatives such as in-house capability and capacity, time-sharing, or service bureaus; • Prepare a formal request for proposal (RFP) to be submitted to vendors; •Evaluate vendor proposals; •Evaluate the economics of lease vs. purchase; and •Assist in the conversion and installation. Thus, consulting services may range from evaluating an existing system and upgrading to a larger piece of equipment, to selecting a new first-for-the-organization computer. First, Define and Summarize Needs Regardless of circumstances, the most valuable document required before equipment selection is the information system plan (I/S plan). It helps insure that the company's information needs are met in a cost-effective manner. An I/S plan is usually a comporient of the mining company's overall business goals. Since an I/S plan is a formal vehicle for establishing and communicating the direction the organization intends to take to satisfy information requirements needed to achieve goals and objectives, most initial systems services are likely to center around creating such a document or updating an existing document. The trend toward company-wide I/S planning is increasing in the mining industry; however, smaller scale efforts focused at the information systems needs to support an individual

Jan 11, 1981

By Phillip Cancilla, Daniel Roy, Frank Rosenblum

"The manual moisture determination methods employed today by mineral processing plants falls short in providing timely information required for automation control. The costs associated with transporting and handling concentrates still represent a major portion of the overall treatment price. When considering the cash flow of a mining operation, that is governed by both the smelter contract, with moisture penalties and the quantity and quality of the concentrates shipped, an efficient method of on-line moisture content would be a welcome tool.A novel on-line determination system for ore concentrate moisture content would replace the normally tedious classic manual procedure. Since the introduction of microelectronic-based control systems, operators have strived to reduce the treatment costs to the minimum therefore a representative and timely determination of on-line moisture content becomes vital for control set points and timely feedback. Reliable sensors have long been on the “wish list” of mineral processors since the problem has always been that you can only control what you can measure. Today, the task of moisture determination is still done in the classical technique of loss in weight by uncontrolled procedures. These same methods were introduced in the earliest base metal concentrators. Generally, it is acceptable to have ore concentrate moisture content vary within a range of 7 to 9%. Many times, delays in manually achieving reliable feedback on the moisture content results in the moisture varying from 5 to 12% before corrective actions can be made.This paper first reviews the traditional and widely available methods for determining moisture content in granular materials by applying physical principals and properties to measure moisture content. All methods are in some form affected when employed on mineral ore concentrates. This paper describes a unique and promising on-line moisture sensor in two mineral processing applications, which not only automates the tedious tasks but also results in reliable moisture feedback that can be used in the optimization of the de-watering process equipment such as pressure or vacuum filters and fuel-fired driers. Finally, two measurement applications will be presented to indicate the usefulness and to summarize the measurement requirements for the proposed method of employing drag force and mechanical properties of the material itself to determine the moisture content."

Jan 1, 2001

By A. A. Berk

Other Federal agencies have been coming to the Bureau of Mines for help with the purchase and utilization of fuel, largely coal, almost since the day the Bureau was created in 1910. The requests covered a wide range of fuel-economy problems and included boiler-water treatment after it became apparent that water-formed deposits on heating surfaces acted as insulators, decreasing heat transfer and impairing fuel efficiency. Dr. Ralph E. Hall, a Bureau of Mines physical chemist determined the reactions that cause adhering scale to form in boilers (7)2 and went on to introduce scientific principles into water treatment for scale prevention (8). Widespread publicity of these achievements increased the requests for help from Federal steam-generating plants. Since no other Federal agency (even those which were more directly concerned with testing water) wanted to provide boiler-feedwater service, the Bureau decided to continue to give requested help to Federal agencies, Later, the Congress endorsed such agency cooperation as an economy measure,

Jan 1, 1963

By Cocquio D. S, Bauchau C

In the course of an integrated airborne survey in 1975, a uranium-molybdenum deposit was discovered by Minatome Australia Pty Limited in North Queensland, Australia, approximately 70 km by road west of Townsville.The mineralization occurs in a welded tuff unit within the Carboniferous St James Vokanics. It is structurally controlled by a complex of subvertical east-west fractures and is exposed over a strike length of 350 m. Drilling has traced a further 150 m extension underneath a barren capping consisting of a thick pile of vokano-sediments. The maximum width of the orebody is 150 m, and its vertical thickness is approximately 100 m.The primary ore minerals are coffinite, pitchblende and molybdenite, accompanied by various alteration products (particularly uranium molybdates).The vein-type mineralization is considered epigenetic.A comprehensive program of surface drilling and underground exploration is in progress to establish the uranium and molybdenum reserves.

Jan 1, 1980

Stope back conditions in the cut-and-fill stopes at New Broken Hill Consolidated Limited often deteriorate to such an extent that, because conventional rockbolts are not able to maintain safe working conditions, square-set timber is installed. An attempt to eliminate this costly procedure has involved the use of long grouted rockbolts using high tensile prestressing wire. These bolts were developed in conjunction with the prestressing engineers of BBR (Aust.). This form of support has improved the back conditions, maintained safe working conditions, and delayed the introduction of timber in a number of stopes.Production from these stopes has been maintained at its previous level (at a rate approximately double that of a comparable timber stope).

Jan 1, 1974

This investigation was planned to determine:1. The precipitation-hardening properties of the copper-nickel-phosphorus alloys; and2. The influence of arsenic and bismuth, singly and together, on the mechanical properties of these alloys.It was carried out in conjunction with an investigation, previously published in these Prooeedings on "The Influence of Various Elements on the Mechanical Properties of Copper containing a small percentage of Bismuth," and also formed part of a study of the influence of bismuth, nickel and phosphorus on the properties of commercial arsenical-copper.The first part of the present investigation arose out of a discovery some years ago of precipitation-hardening in phosphorus-deoxidized coppernickel boiler tubes, containing approximately 2% nickel and 0·03% phosphorus, supplied to an Australian Railways Department. At that time there was little information available on precipitation-hardening in copperrich copper-nickel-phosphorus alloys, but at the end of 1935 a short paper on the subject was published by E. C. Rollason and T. G. Bamford(2) and at the beginning of 1940 a comprehensive account was published by D. K. Crampton, H. L. Burghoff and J. T. Stacy.(3) Although the investigation carried, out independently by the present author was not as comprehensive as that of Crampton, Burghoff and Stacy, the results are in agreement with those of the American as well as of the British authors; hence, only a summary of this aspect of the work is needed here to establish a basis for a study of the influence of bismuth and arsenic.PREPARATION OF TEST PIECESAll alloys were melted under charcoal in plumbago crucibles in an oil-fired furnace and were poured out of contact with air into oil-dressed moulds to give billets either 7· 5 in. long X 0.83 in. diam. X 1·3 lb. weight or 12 in. long X 1·125 in. diam. X 3·3 lb. weight depending on requirements (the larger size was used, for example, in establishing the annealing characteristics of the precipitation-hardening alloys). The raw materials were electrolytic copper of the composition described in the previous paper(I) 6% copper-arsenic, 14% copper-phosphorus, 1:7% copper-bismuth, and Mond nickel in the form of "shot." The method of producing test pieces from these billets and the annealing treatments ana tests to which the pieces were subjected have been described in the previous paper.

Jan 1, 1944

By F. Ziaie

Line electrical resistivity method using physically infinite distance between current line electrodes is proposed to determine the location of mine workings. In this method at least three line electrodes are used. One of the current electrodes is used as a sinkhole electrode while the other two are used for different activiations of line electrodes when the survey area is between one of the line electrodes and outside the other one. The resistivity profiles perpendicular to the current line electrodes for different activation of electrodes is plotted versus the distance of the midpoint of the measuring potential electrodes. The anomaly due to presence of any locally lateral resistivity variation (e.g. mining cavity) will represent itself as peak or trough depending on resistivity contrast between the source of the anomaly and surrounding medium. Physical simulation of the proposed model was conducted by using a tank model in the laboratory. The results of experiments appear to be consistent with the theoretical model. Experiments for different depths and different spacial locations of the simulated cavities appeared to be successful for locating the depth and size of the cavity.

Jan 1, 1989

The C.S.I.R.O. acid alumina process employs the essential steps of digestion, hydrolysis and calcination to produce pure alumina from ores too high in silica or too low in grade for the Bayer process. The two latter stages have been described in some detail previously but the digestion stage requires separate discussion since ores vary widely in composition and reactivity. Kaolinitic clays require roasting to 800°C to render the alumina soluble in the 11 per cent sulphuric acid used in the process while some ferruginous laterites require roasting to reduce the reactivity of iron minerals.The iron content of pregnant solutions is kept at a low figure by digesting at temperatures where the solubilities of ferric oxide or basic ferric sulphates are small. A two-stage, counter-current digestion is necessary to extract a high percentage of alumina from the ores and to produce a basic pregnant liquor with an SO3 : AI 203 ratio of 1'\1 suitable for high temperature hydrolysis. The second stage of digestion, called the modification stage, treats slightly acid liquors with excess of ore in the temperature range 1200-1400C.The first stage operates at 170°-1900C to extract further alumina from modification residues, using recycled acid obtained from later steps of the process. Both temperature ranges are critical for economic operation and for proper control of the iron content of solutions. In batch experiments, 30 min is regarded as a suitable retention time for digestion and modification; ores which require much longer than this are less suitable for the process. Impurities such as silica, and titanium and vanadium oxides are discarded in the residue along with iron oxide, and do not contaminate the final product. Bivalent metallic sulphates such as MgSO4, can build up in the circuit to a very considerable degree without affecting product purity.Comparison with other processes shows that the C.S.I.R.O. process is superior for control of contamination by iron, which is the major problem in acid processes. The pure intermediate product (3Al203.4S03.9H20) is also more convenient for calcination to alumina than the hydrated aluminium sulphate usually recovered in other processes. Detailed cost comparisons must await pilot-plant evaluation of the C.S.LR.O process.

Jan 1, 1964

By L. Garycki, P. Poks, R. Urbaniak, T. Gabka

In 2016 at Głogów Copper Smelter KGHM Polska Miedź S.A., after shutting down the shaft furnaces new FSF was launched. Currently, it is the only smelter with two direct to blister flash smelting furnaces in operation. The main difference between the vessels are the dimensions and production capacity. The new furnace design output is about 30% higher compared to the old flash smelting furnace working for 40 years. The paper presents a comparison of both FSFs operation, differences in technology and the way to optimize the process to maximize efficiency. INTRODUCTION KGHM Polska Miedź S.A. is the only company in Poland (eastern part of Europe) that extracts and processes copper ores. It is located in the south west of Poland and this region is called the "Copper Basin”. KGHM PM S.A. consists of three underground mines: Lubin, Polkowice-Sieroszowice, Rudna, concentrator plants, a tailings pond plant, three copper plants: Legnica, Głogów and Cedynia wire rod plant in Orsk. The publication relates to the operation of the furnaces in Głogów (the plant in Głogów consists of Głogów 1 and Głogów 2 which form integrated smelting and refining facilities). In 2016, after closure of the shaft furnaces technologies in the Głogów 1, a new FSF commenced operation. The simplified process flow sheets are given in Figure 1 and 2. Technological schemes are similar, but due to the differences in them, they will be discussed separately. Głogów 1 Enriched ores are discharged and directed to the feed preparation plant. Delivered concentrates are built up on the three bedding aisles in appropriate proportions. The concentrates are distributed in even layers in one of the three aisles. Aisle emptying is done with a blending machine which cuts across the concentrate layers and collects thus blended material, sending it via belt conveyors to a storage bin. From the cross- blending machine and conveyor assembly, the mixture of concentrates is directed to drying in the steam dryer. Part of the charge is directed to the FSF and part to the roaster for carbon elimination. Known in the world roasters are used to eliminate sulfur compounds or arsenic. In the case of KGHM deposits, the aim of the process is to reduce the energy value of the feed by eliminating carbon and converting sulfur from sulfide to sulfate. Changing the nature of exothermic to endothermic material is crucial in the case of furnace operation with design performance. Roaster is a separate furnace with an innovative character.

Jan 1, 2019

By Lawrence M. Gochioco

The interpretation of coal seismic data requires a certain precision and accuracy to make the results more reliable. The signature of the seismic wavelet provides a host of valuable geologic information. Subtle features and anomalies, not easily observed in conventional black and white seismic sections, are enhanced through color attribute displays in terms of frequency, amplitude and phase. Coal seam anomalies like sandstone washouts produce a distinct pattern in frequency and amplitude displays due to the change in the net acoustic impedance contrast. Faults produce frequency and amplitude variations due to interference within the Fresnel zone that straddles the fault. The magnitude of displacement is estimated by studying the effects of faults on reflection amplitudes and frequency from computer-generated models.

Jan 1, 1989

By Jon Bowler

Daw Mill Colliery, UK Coal, near Coventry in England, mines the Warwickshire Thick Seam at 800 m/2500 ft depth using longwall retreat with gateroads supported by rockbolts. Over the last eight years the mine has worked longer and wider panels with extraction heights of over 5 m. Recently the mine has experienced high deformation conditions principally from the rib sides resulting in operational issues and production delays. Investigation of rib deformation was undertaken using new inspection and measurement techniques, including systematic laser surveying, and improved rib support consumables were developed and introduced. A new rib trussing system using textile webbing has proved very successful.. A rib support management system was also developed and introduced for face retreat. This allowed rib support to be more effectively managed both for production and safety. For the current developments, new 28-mm-diameter roof and rib bolt systems have been introduced and rib bolt length has been increased to 3 m, with the aim of achieving gateroad stability over the life of the panel. Significant reductions in roof and rib deformation have been confirmed by the latest monitoring results. These ground control innovations are allowing Daw Mill?s potential to be realised. Production from 302?s face in 2008 set new UK and European records. However the support enhancement process continues and further innovations are planned.

Jan 1, 2009

By M. Seeger

The demographics and the growing numbers of people provide a strong signal that the demand for electrical power in Southern Africa will grow considerably over the foreseeable future. Without a steady and increasing supply of electricity development of the continent is likely to be constrained. The inventory of solar, wind, hydrothermal, geothermal and biomass resources will probably provide sources of energy for the future The parallels between extraction of natural resources in the minerals industry and the green energy industry is striking, and the well-established project development process in the minerals industry provides an ideal and useful template for comparing the establishment and development of green energy projects. The potential levels of power generation and carbon savings are described.

Jan 1, 2010

When Haematite Explorations Pty. Ltd. began prospecting for petroleum in 1960, there was only ill-defined geological evidence on the land bordering Bass Strait to support the belief that petroleum lay trapped in sedimentary formations beneath its shallow waters.A reconnaissance of the area, made in 1961 by the airborne magnetometer method, covered the waters and islands of the Strait and overlapped the Victorian and Tasmanian coasts. The survey indicated the presence of the Bass Basin (which is completely water-covered), assisted in outlining the Otway and Gippsland Basins, and showed that each basin contains sedimentary rocks over 10,000 ft thick. Information on the regional geology and minor volcanic activity was also obtained.Marine seismic surveys carried out from 1962 to 1965 defined these basins more accurately and showed the nature and structure of the thick sedimentary sections.Correlation of the seismic data with onshore wells identified the sediments as Tertiary and Mesozoic. Subdivisions of the former in all basins and the latter in the Otway Basin were made. These Tertiary and Mesozoic rocks are not seriously deformed and they have good prospects of containing petroleum.Possible structural and stratigraphic traps, recognized from the seismic record sections by petroleum geologists, are being tested by offshore drilling which began in 1964.

Jan 1, 1966

By Rudolph P. Frizzi

Quality control is essential for augered cast-in-place (ACIP) piles (also known as continuous flight auger (CFA) piles outside the United States) and drilled displacement (DD) piles since the pile is constructed below the ground surface out of the direct sight of the personnel constructing and inspecting the pile. ACIP piles are being successfully constructed to support high-rise structures, hospitals, arenas and stadiums, mass transit systems, and power and industrial facilities. The use of DD pile technology is also gaining ground in the United States, typically utilizing proprietary systems such as Omega (currently utilized by Richard Goettle Inc., and LG Barcus and Sons, Inc.), Berkel, and DeWal (currently utilized by Morris-Shea). Different types of ACIP/DD pile installation equipment are shown in Figures 1 and 2. ACIP piles are installed into granular and cohesive soils, and soft rock to lengths currently approaching 130 ft (39.5 m), with diameters up to 24 to 36 inches (610 to 915 mm), and sustaining design loads approaching 900 kips (4000 kN). Current DD pile installation equipment in the United States is capable of installing up to 79-ft-long (24 m) piles with diameters ranging from 12 to 18 inches (305 mm to 460 mm).

Jan 1, 2003

By Zhu Tonghao

A method of calculating anti-slide pile, sheet pile, underground diaphragm and structure with anchors etc. is proposeed in the paper. The effect of the various layers of soil, anchors and bracings etc. on laterally loaded structures may be considered in the model. In the analysis the structure is divided into a series of elements. The transfer matrices of both deformation and internal force are established for each element. According to continuous condition neighbouring element should be connected. Thus the deformation and internal force of each element can be found out in conbination with boundary conditions. The method has a wider adaptability and it can be applicable to a great variety of the analysis of interaction between various structure and soil. If parameters in model are selected properly, the computed results would be in good agreement with the measured data.

Jan 1, 1991

By Kausik M. Sinha

Hydraulic stowing, which is being practiced in several major coal producing countries to deal with adverse mining conditions, usually permits almost 100% coal recovery from underground mines with minimal and controlled surface subsidence. It can be implemented in the US coal mines to reduce the severe effect of land subsidence and at the same time improve the cost of coal production, both of which are major setbacks for the coal industry in the USA

Jan 1, 1989