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By Joseph Goessling, Mark Kroncke, James Parkes

The I-35 Capital Expressway (CapEx) Central Drainage Tunnels will serve as a stormwater collection system for the forthcoming I-35 Capital Express Central reconstruction project through downtown Austin, Texas. The schematic level concept design included three tunnels, 10 to 14 ft ID, totaling 26,000 LF. Constructability reviews during design development indicated issues with the concept design including phasing of construction, conicts with future retaining walls, staging area concerns, and signicant mixed face tunneling. The design was updated to mitigate these risks. The revised design includes two tunnels, both 22-ft ID and totaling 33,000 LF, that will be mined almost entirely in rock.

Jun 23, 2024

By Mao Bai

In predicting the integrity of under-mined structures, surface horizontal displacements and curvatures are frequently of greater importance than the more homogeneous vertical displacements. Accurate evaluation of mining induced subsidence and horizontal displacement further requires that the predictive model adequately represents the subsurface geology, mining geometry and extraction sequencing. The following documents an extension of the Subsidence Prediction and System Identification method (SPASID) to the evaluation of horizontal strains. Comparisons are made between predictions from SPASID and two other empirical methods against measured data from a case study. The system identification method is illustrated to predict horizontal displacements and strains most consistently with the in situ data.

Jan 1, 1989

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 T. S. Qiu

In view of the bad effect that Na-bentonite direct adsorb Pb2+-containing wastewater, this article has carried out two kinds modification treatment on Na-bentonite: the direct microwave radiation modification and microwave radiation organic modification by adding quaternary ammonium salt?cetyltrimethylammonium bromide,and analysis the main influencing factors of the modification effect. In static conditions, preparing Pb2+-containing wastewater as the research object, it has respectively studied the effects of Na-bentonite, microwave soil of direct microwave modification and microwave soil of organic modification on the process of adsorption Pb2+, and discusses the effects of pH value, temperature, adsorbent dosage, stirring time on the adsorption Pb2+ in wastewater by modified bentonite, at the same time it does a verification test to the practical Pb2+-containing wastewater. Comparison the effects of adsorption Pb2+ in wastewater, the results show that organic modified microwave bentonite is obviously better than direct microwave modified bentonite and Na-bentonite, and can make 6 mg/L Pb2+-containing wastewater meet the national discharge standards. Through scanning electron microscope, the result of test is that organic modified microwave bentonite is the cause of improving adsorption Pb2+ in wastewater. Preparing modified bentonite by microwave heating will not only shorten the response time, reduce energy consumption and work-load, but also modified effect is good.

Jan 1, 2014

By R. L. Russell

Production at Freeport Indonesia's Ertsberg open pit copper/gold mine started in 1972 at a rate of 7500 t/d. Mill throughput remained at that rate for a number of years until the discovery of the Ertsberg East (GBT) orebody. This discovery prompted three successive expansion stages from 1981 to 1988 that boosted production to 20,000 t/d. The discovery of the huge Grasberg porphyry copper deposit in 1988 launched a new era of much larger expansions. The first of these involved installation of a fourth primary mill in 1989 to bring production up to 32,000 t/d and was immediately followed by an expansion of the crushing and screening plant and the addition of a new south concentrator to bring production to 57,000 t/d in 1991. The addition of a primary ball mill and the changeout of the original Denver flotation cells in 1993 has served to optimize current production at a level of 66,000 t/d. A major expansion is now in progress. This includes construction of another new concentrator to house a SAG mill circuit and large Wemco flotation cells in an area created by the removal of 6,000,000t of glacial material. This current expansion, with a planned completion in 1995, will take production to 115,000 t/d. This paper describes the evolution of the Freeport Indonesia (FI) concentrator to-date and will then go into an in-depth discussion of the 66,000 and 115,000 t/d expansions.

Jan 1, 1994

H. W. Turner, Portland, Ore. (communication to the Secretary*) :—Mr. Brown's paper on the complicated groups of veins exposed in the workings of the Bodie mine forme a valuable contribution to the literature of the structural features of ore-depoeits. It is much to be desired that managers should put into print the results of their observations of the mines under their charge. These observations, as well as data of production, kind of ores, etc., usually accumulate for years, and unless the mining geologists of the Geological Survey happen along before the mine is worked out, such data seldom get into print. About the year 1899 I went through the mines at Bodie with R. C. Turner, then superintendent, and made some notes on the veins and gangue-minerals, and collected some specimens. Mr. Brown refers to crystals of feldspar (albite) found on fragments of quartz on the surface. I collected a number of specimens of these crystals, mostly from Queen Bee hill, and

Jan 1, 1909

By R. Brantley Sudderth

There are three broad categories in which most solvent extraction technology can be distributed?: 1) reagents, 2) equipment, and 3) systems. Reagents which are now used in commercial solvent extraction plants are of many chemical types, and each possesses certain properties which make it more economically desirable than another alternative. The equipment which is' used in solvent extraction plants for contacting the organic and aqueous phases and separating the same is varied. Most common to the industry is the mixer-settler unit which in itself, can be of varied design; but many new innovations in contacting and separating equipment have been recently introduced or are :now being studied. Each specific solvent extraction application will often dictate the type of contacting and separating equipment used. Obviously, the trend is toward smaller less expensive equipment which reduces the often expensive organic inventories necessary for most solvent extraction plants. The current thrust of .investigations in ancillary equipment is usually aimed at recovering organic from solvent extraction sludges or from aqueous streams exiting the process.6 This type of equipment helps to reduce the total organic losses from solvent extraction plants and thus reduce the operating costs. The term "systems" in solvent extraction applies to the manner in which a solvent extraction process is carried out. This manner is usually dictated by the properties of the reagent which is used, and it involves a tailoring of the equipment or the process flowsheet. Some of the things which can be tailored are: 1) The aqueous media -whether acidic or basic and what type of acid or base 2) Counter-current or single stage (co-current) contacting 3) EMF or pH control 4) Organic "crowding" alternative 5) Heating or cooling process streams Regardless of the type or extent of tailoring, efforts to do this are usually a result of the low cost of solvent extraction as a unit process.

Jan 1, 1977

By B. Mishra

Several reactive metal purification processes using molten salts generate effluent from which significant quantities of metal can be recovered prior to discardinglrecycling the salt. A Salt-scrub [SS] process has been applied where the reactive metals are recovered as a metal-gallium alloy by calciothermic reduction of the metal compounds. The SS alloy compositions were produced by mixing, pressing and sintering the metal-powders. Measurement of metal recovery has been studied for cerium, silver, tin and lead. The process has been optimized for variables such as the metal quantity per kg of effluent salt, amount of excess calcium over stoichiometry, stirring rate and time and holding time at reduction temperature. Over ninety-seven percent metal recovery has been obtained under optimized conditions. The development of an alloy for efficient Salt Scrub processing reduces a major contaminated waste disposal problem as well as recovering the valuable reactive metal. Surrogate metals have been used in this work to study the behavior of plutonium.

Jan 1, 1994

In the United States water pollution resulting from mining activities has long been recognized as a major environmental problem Mine drainage pollution results from many types of mining activities and includes both physical (i e , sedimentation) and chemical (i e , acidification, metal contamination, etc ) pollutants Active and abandoned surface and underground mines, mineral processing plants, mine and processing plant waste disposal areas, haulage roads, and tailing ponds are typical sources of mine related water pollution (130) One of the most serious pollution problems arising from mining activities is acid mine drainage resulting from the chemical reaction of sulfide minerals (commonly iron sulfides) and air in the presence of water Acid mine drainage is commonly associated with coal and hard rock mining areas in the United States In general the more serious and extensive acid mine drainage problems exist in the more humid coal regions east of the Mississippi River (11) In 1964 the U S Department of the Interior, Fish and Wildlife Service, reported that acid mine drainage adversely affected fish and wildlife habitat in 9,477 kilometers (5,890 miles) of streams and 6,062 hectares (14,967 acres) of impoundments in 20 states in the United States (64) Of the total affected waters, coal mining operations accounted for 97 percent of the acid mine drainage pollution reported for streams and 93 percent of that reported for impoundments In 1970 more than 19,308 kilometers (12,000 miles) of streams in the United States were reportedly significantly degraded by mining related pollution (130) Of the total affected kilometers, 16,920 kilometers (10,516 miles) or approximately 88 percent were located in the Appalachian coal region (Pennsylvania, West Virginia, Ohio, eastern Kentucky, Tennessee, Maryland, and Alabama) In addition, more than 965 kilometers (600 miles) of streams reportedly were degraded by coal mining in states in the Illinois, Western Interior, and Rocky Mountain coal regions The remaining portion of the stream pollution resulted from the mining of (1) copper (california, Montana, Nevada, New Hampshire, Tennessee, Virginia, and Wyoming), (2) lead and zinc (Colorado, Idaho, Kansas, Missouri, Montana, Oklahoma, and Tennessee), (3) uranium (Rocky Mountain States), (4) iron (Lake Superior iron region), (5) sand and gravel (all states), (6) phosphate (Florida and other states), (7) gold (Alaska), (8) bauxite and barite (Arkansas), and (9) molybdenum, gold, and other metals (Colorado) Abandoned mines and abandoned mine waste disposal areas contribute a large portion of the total pollution resulting from mining activities Numerous abandoned underground mines are located throughout the United States and many are discharging mine drainage pollutants In 1966 the U S Bureau of Mines estimated that more than 88,000 inactive and abandoned underground mines were in existance (126) A listing of these mines by state is presented in Table 1 0-1 More recent estimates indicate that this list is incomplete In Colorado alone there is

Jan 1, 1975

By Neal Lee

Often the effects of wet boreholes are not taken into consideration when designing a blasting program to exhibit a certain amount of explosive energy per unit of rock such as design by powder factor, expressed in lbs./bcy (pounds explosives per bank cubic yard) or kg/bcm (kilograms per cubic meter), often the effects of wet holes are not considered. This paper examines different methods of loading wet holes and the effects they have on actual explosive quantities/unit of rock. In particular, we are looking at the amount of water trapped within the explosive column (bulk loading from the collar), or the annular space left void of explosives product around and between cartridges (wet-bags) with many of the current wet hole loading methods in use. We will focus on the effect this has on actual powder factor relative to “as designed” dry hole loading values, as well as the effect on performance of the explosives.

Jan 1, 2011

By Don Houston

Vertical crater retreat mining (VCR) requires initiation methods that minimize debris in the borehole. The use of detonating cord and shock tube detonators eliminates debris that could interfere with subsequent loading operations and avoids the cost of using drilling equipment to clear the debris. The explosive must not be sensitive to the strength of detonating cord used, otherwise timing will be affected. “Slicing and Dicing” of product before “Air mailing” down boreholes may facilitate loading, especially in wet holes, and can result in product surrounding the detonating cord. Cord sensitivity testing confirmed that having the detonating cord surrounded by product significantly increases the likelihood of an energetic reaction. Careful formulation and testing, based on a thorough knowledge of the application and the role of ingredients in affecting performance, ensures reliable initiation and avoids cord sensitivity. The use of certain metallic nitrate salts, even in relatively small amounts, was found to significantly increase the cord sensitivity of watergel formulations. Evidence of increasing cord sensitivity includes increasing amounts of damage to product and packaging, to ejection of product from the test pipe, then cracking of the pipe, followed by deflagration then detonation of the product. Predictably, the likelihood of an energetic reaction increases with product temperature, cord strength, and borehole diameter, while it is inversely related to product density.

Jan 1, 2002

By J. David Chapman

There are a variety of choices of materials for mineral extraction processing. Traditionally, end users have used metallic piping for fluid handling and little is known about the advantages (or limitations) of non-metallic piping systems. This presentation will review custom FRP pipe systems and their use in severe corrosive and erosive process streams. These systems can be designed to various pressure and temperature ratings and different components (such as resin and glass type) can be varied to suit the process conditions

By Miguel Ângelo Menezes, Carlos Alberto Alves Viana

O presente trabalho possibilita o entendimento e a análise dos processos de conformação a quente dos metais. Isto, pela validação experimental do modelo de Johnson-Cook, para descrever o comportamento dos materiais no regime plástico, para grandes deformações, às altas taxas de deformações e nas altas temperaturas. Um entendimento dos parâmetros do modelo, utilizando-se um método analítico numérico simples, rápido e confiável foi desenvolvido anteriormente pela linha de pesquisa em Conformação Plástica dos Metais na UNESP – Campus de Ilha Solteira, obtendo-se as constantes empíricas do modelo referido. É proposto nesse trabalho a validação experimental do método simplificado para determinação dos parâmetros empíricos do modelo de Johnson-Cook através de um ensaio de tração a quente, considerando as propriedades mecânicas dos materiais analisados experimentalmente e/ou de dados de materiais disponíveis na literatura. De maneira geral, os resultados experimentais foram satisfatórios para o aço AISI 1045 à temperatura de 500 ºC, ensaiado à taxa de deformação de 1000 s-1, quando comparados aos resultados teóricos previstos pelo modelo proposto por SCADUTO e MENEZES. Particularmente, foi possível evidenciar erros máximos de 1,33% para o parâmetro n, 13,15% para o parâmetro B, 295,00% para o parâmetro C e 4,14% para o parâmetro m.

Nov 11, 2019

By J. Patterson

"Acid Mine Drainage (A.M.D.) formed from oxidation of disposed pyritic wastes presents a potential pollution hazard for Equity Silver Mines Limited and the mining industry in general. Failure to collect and treat these acidic effluents can eventually affect the quality of receiving streams and endanger aquatic life forms. Treatment and discharge of A.M.D. to the receiving environment must comply with stringent anti-pollution laws.Wastes mined at Equity Silver Mines Ltd. are predominantly acid generating and must be handled according to a materials management plan to minimize impact on the environment. Effluent collection and treatment facilities have been constructed to address the short term environmental concerns with reclamation and research programs being developed to address and monitor abatement measures for control over the long term.The purpose of this paper will be to offer a brief overview of these measures. Key topics for discussion will be: kinetics of Acid Mine Drainage, acid generating potential, water treatment and sludge handling, special wastes, waste dump construction, waste rock amendments, bacteriocide research, simulations, and reclamation measures. Programs designed to evaluate impact on the receiving environment, although they form an extensive part of the program, will not be discussed in this paper.INTRODUCTIONEquity Silver Mines Limited is located in the Central Interior of British Columbia, within the Omineca Division, 35 kilometers southeast of Houston Mining and approximately 575 kilometers by air north-northeast ofVancouver (Figure 1).The deposit consists of three economic mineralized zones: The Southern Tail, Main and Waterline Zones. Mining of the Southern Tail commenced in April, 1980 and was completed in the first quarter of 1984. Main Zone production was initiated during the last quarter of 1983 and the Waterline Zone remains undeveloped to-date. Remaining reserves are in the order of four years contingent on favourable metal prices. The three deposits (Figure 2) occur within a window of interbedded volcanic and minor sedimentary rocks. The older volcanic sequence is bounded on the west by a small granite-like stock and on the east by a gabbro-monzonite complex. All are overlain by a series of younger lava flows."

Jan 1, 1988

By V. D. Tathavadkar

Chromite ore is of immense importance for the extraction of metallic chromium and chromium chemicals. The mineralogy and crystal structure of chromite phase are therefore important part of our investigation on the extraction chemistry of chromium species. In this investigation, we have studied the effect of the processing parameters, i.e., the temperature and the oxygen potential on the microstructure and composition of mineral phases formed in the Cr2O3 ?Al2O3 -FexOy -MgO system. In particular the importance of the spinodal decomposition reaction is emphasized in the extraction of chromium as sodium chromite and sodium chromate. Experiments were carried out in order to study the differences in the crystallography of different chromite minerals. Phase equilibria in natural chromite minerals were investigated by calcining chromite mineral in air, argon, and 5% hydrogen + argon atmospheres over a temperature range from 200 to 1200 °C. The effect of the oxygen partial pressure and temperature on the phase constituents of the calcined product has been discussed. The microstructural changes were examined using scanning electron microscope (SEM) and the changes in elemental composition in different phases were analysed by electron probe micro analyser (EPMA). The results obtained from EPMA studies were used to calculate lattice parameter of the spinel lattice, and these values were compared with the values obtained from X-Ray powder diffraction data. On the basis of the experimental data, the mechanism of the spinodal decomposition of complex spinel phases is described under the influence of oxygen partial pressure and temperature.

Jan 1, 2000

By D. Steele, B. Ndlovu

"Adequate characterisation of clays is becoming increasingly important as operating mines move into areas of more complex ores. The processing therefore needs better mineralogical characterisation to identify problematic ores for better planning before issues arise. While a number of instrumental mineral characterisation methods are available, X-ray Diffraction (XRD) is widely recognised as perhaps the best technique for the identification and quantification of minerals, particularly clays. When an appropriate sequential and systematic sample preparation and treatment protocol is employed with instrumental XRD analysis individual clays can be uniquely identified, and the proportions of interstratified clays can also be quantified. The effect of sample preparation on the XRD analysis and identification of clays was investigated in this study. The results showed that sample preparation protocol is indeed critical to accurately analysis and characterisation of clays. For example, both dry grinding and micronizing affected the degree of crystallinity of kaolinite leading to the formation of reactive surfaces or changes in the physicochemical behavior. It was also found that the apparent degree of preferred orientation in platy minerals correlates directly with the amount of force/pressure applied during the preparation of backfilled powder samples. This work showed that manual preparation can produce highly variable peak intensities especially with minerals that show any preferred orientation. KEYWORDS Clay; XRD; kaolinite INTRODUCTION Clays are important in our life and they have numerous applications in modern world from cosmetics to environmental remediation. Therefore, clays have been extensively investigated for many years. Adequate characterisation of clays is becoming increasingly important as the mineral processing industry faces more complex mineralogy with the need for better mineralogical characterisation to identify problematic ores and plan accordingly. In most studies, X-ray diffraction (XRD) method has shown the unique capability to characterise mineralogy, especially for the fine grained size materials. The XRD technique is particularly diagnostic for clays. It is known that under ideal conditions, the peak intensities of an XRD diffractogram are proportional to the concentrations of individual minerals present in the sample. Hence, the qualitative mineralogical data obtained from XRD can be quantified, using either the internal or external standard methods. However, it is also known that clays are particularly sensitive to the influences of sample preparation method due to their physical characteristics (e.g. fine grain size, morphology, relative physical softness, crystallinity, thermal sensitivity) that could be destroyed by inappropriate preparation prior to the analysis. Thermal and mechanical treatment and grinding of clays can change their crystalline structure, and consequently, their characterisation results by XRD analysis. The behaviour of clays in grinding has been widely studied, especially for kaolinite (Miller and Oulton, 1970, Milocevic et al., 1992, Tomasevic-Canovic et al., 1992). With prolonged grinding time, the crystallinity of the clays can decrease (Filipovic-Petrovic et al., 2002). It has been shown that grinding may gradually cause the loss of hydroxyl ions of kaolinite (Gonzalez Garcia et al., 1991)."

Jan 1, 2018

Iron Ore - Mineral Processing Overview Several years of iron ore price increases, coupled with a period of strong global demand for raw materials, presented iron and steel producers with unprecedented costs and difficulty procuring the demanded high quantities of iron ore. These conditions spurred many companies to investigate new ore bodies and also reassess past decisions (such as divestment of captive iron ore mines that ensured dedicated supply or a move to reliance on the 'spot market' instead of long term contracts with suppliers) and revisit alternative sources of iron units, including low grade deposits, tailings reprocessing, Ti-rich ores, and iron sands. To properly upgrade these iron sources requires a complete battery of mineral processing techniques. Within different regions around the world, operations and technology have developed to specifically beneficiate the local ore bodies. This paper attempts to bring these different general processing techniques together to allow insight into various common and proven methods of iron ore beneficiation. This paper further explores the current trend to develop global iron ore reserves, and discusses the methods to beneficiate and successfully reduce and smelt iron ore using Outotec's physical separation, direct reduction and smelting technologies for final production of pig iron and slag. Use of these various technologies may allow treatment of what was typically considered a tailings stream into a profitable product.

Sep 13, 2010

By J. K. Whyatt, B. G. White

A comprehensive survey of mine seismicity and rock bursting during development of two sublevels at the Lucky Friday Mine, Mullan, ID, USA, was conducted to better define rock failure mechanisms and sources of ground control hazards. Survey data included rock burst damage reports, seismic event locations and magnitudes and, for the most energetic events, first-motion information. Several subsets of this database, including large seismic events, rock bursts, and microseismic activity near the face, were analyzed. Elements of the large-event and rock burst data sets were nearly independent. That is, there was no relationship between the risk posed by a seismic event and its energy, although such a relationship is well established for the mine as a whole. All data sets showed that certain geologic features appear to control the spatial distribution of events and the spatial distribution of rock burst risk. The data also suggest that, within the scope of this study. the greatest risk of injury occurs when a pocket of heightened rock burst risk is first encountered and that this risk is controlled when miners adapt their practices to these conditions. Recognition of the role of particular geologic features in the spatial distribution of rock burst hazards provides an opportunity for anticipating, rather than only reacting to, a changing level of rock burst hazard- However, much work will he required to make good on this promise.

By Franklin P. Hall

U.S. supply and demand data for utility electricity by States and regions were tabulated for the years 1960 and 1965. Estimates are provided of State-by-State quantitative data for the utility electricity industry that can be integrated into State and regional energy balances by source, form, and major consuming sectors, and used to determine basic flow-patterns. The difficult problem of compiling interstate and interregional shipments of electricity was resolved by (a) assuming the negligibility of interregional shipments and (b) deriving a theoretical line loss percentage used for determining interstate shipments. The data developed were able to show an estimated total supply of utility electricity available for consumption. The tables also report the distribution of the supply among the major consuming sectors (household and commercial, industrial, and transportation). To compare the various energy sources of utility electricity, quantities were converted to their British thermal unit (Btu) equivalents. The Federal Power Commission, Edison Electric Institute, and Bureau of Mines are the sources of the data used in this study.

Jan 1, 1969

In March 1990, Heritage Mining conducted a 2000 line km high resolution aeromagnetic survey of all its prospects in the Coromandel Peninsula. One of the areas covered was the Onemana Peninsula, situated about 5 km north of Whangamata. Details of location and geology are given by Robson and Stevens (this volume).   The detailed helicopter-borne magnetic and radiometric survey over the Onemana area consisted of 163 line kmÆs of flying, and was carried out in order to assist in the definition of hydrothermal alteration and pre- or post- mineralisation structures. The line spacing chosen was 100 m, flown east-west, with a mean sensor terrain clearance of 80 m. Tie lines were flown north-south every kilometre for levelling purposes. The sensor was a Geoinstruments G-813 proton precession magnetometer in a towed bird, with data recorded using a Geoinstruments G-2000 acquisition system.   The Onemana alteration system is at the northern end of a major north-north east trending structural corridor defined by regional aeromagnetic surveys performed by AMOCO in 1980 (Rabone, 1991). T his structure hosts a number of other extinct hydrothermal systems including Karangahake and Golden Cross. In the Onemana contour plot the predominant north-northeast structures form the boundaries of a large area of subdued magnetism in the southern part of the surveyed area that is caused by intense hydrothermal alteration. This area is about 3.5 km long by 1 km or more wide and contains outcropping sinters and hydrothermal eruption breccias, as described in Robson and Stevens. A number of other structures transect this alteration zone, with strike directions ranging from northwest to north. A northwest feature notably truncates the zone to the south, while the northern end seems to be simi1arly bounded; however as data coverage ends at the coast, this feature is less conclusive.    Two distinctive types of strongly magnetic rock were discernible the contoured data. The strong negative magnetic anomalies the north and west are caused by fresh negatively magnetised rhyolites. This was confirmed by ground follow-up work that showed the rocks to be fresh biotite rhyolites with high magnetic susceptibilities.

Jan 1, 1991