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By Douglas W. Christie

Deep foundations in Washington, DC have played a role in the city?s development since the 19th century. Designers of government and commercial buildings sought deep foundations initially to minimize settlement of structures. As the western portion of the National Mall was made by filling in portions of the Potomac River, numerous memorials and monuments on the Mall required deep foundations. In recent years deep foundations have been used to allow underground construction for various reasons. Commercial developers have sought to maximize the use of sites by developing below-grade space for parking to meet code requirements and offset the limits on building heights. Underground museum and gallery space has been constructed to expand public space while preserving open space above grade. Access and security concerns have prompted the design of underground visitor centers rather than above-grade structures.

Jan 1, 2006

By J. F. T. Agapito

OCI Wyoming mines two flat-lying trona seams that are 3- to 3.5-m- (10- to 11.5-ft-) thick, about10 m (33 ft) apart and 250-m- (820-ft-) deep at its Big Island Mine in Wyoming. Continuous miners and a yielding-pillar system have contributed to improvements in resource recovery and productivity. The use of yield pillars minimizes the stresses transmitted from the upper to the lower seam. However, yielding must not impact the good, long-term stability needed to prevent subsidence for a large portion of the mine beneath the Green River channel.

Jan 1, 2000

By K. W. Lee, C. Pound, J. Carmody, L. Petersen, C. Nelson, J. G. Cai

The feasibility of developing the Underground Science City below the Kent Ridge Park has been investigated. The primary aim of the study has been to explore the possibility of creating underground space to house a new community of research laboratories and offices. The investigation represents the first such study undertaken in Singapore for a non-military underground facility. The paper describes the geology of the Underground Science City site and illustrates the layout and plan of the Underground Science City. The geology and rock mass below the Kent Ridge Park is generally favorable for the development of an underground cavern complex. Underground Science City can be potentially developed housed in a cavern complex. Several potential development schemes are studied; with various combination of deep/shallow mined caverns of different span sizes and access options. The preferred scheme is shallow, mined room-and-pillar caverns with large spans and shaft accesses at both existing surface Science Park 1 and Science Park 2. The scheme can be potentially expanded laterally to create more underground space for new Underground Science Cities at Kent Ridge area.

Jan 1, 2001

ONE DAY IN the mid-1880s, in a suburb 0f Pittsburgh, Pennsylvania, there dismounted from a train the two foremost leaders of the day in the coal and steel industries-Andrew Carnegie and H. C. Frick. Their attention was drawn to a well-loaded car of coke, which their experienced eyes recognized as a superior product. "I'll bet you that coke is from the H. C. Frick Coke Company," Mr. Frick challenged. "I'll bet it was shipped by my company." In a spirit of fun Mr. Carnegie accepted the wager. Mr. Frick lost the bet: the coke had come from M0rewood, one of three sites being operated under the direction of a young entrepreneur, Erskine Ramsay. If Mr. Frick's confidence was somewhat dented by this occurrence, the responsibility was his own. He himself had opened the way for Erskine Ramsay to become the youngest of mine superintendents; and he had dispersed all dissension regarding his choice with the words : "I'm not interested in his years, I'm interested in his record. He makes more coke in an oven than any other superintendent. And I'll take 'em out 0f the cradle if they can make coke... Suppose he is only twenty years old? ... The d --- kid is a genius, I tell you." Erskine Ramsay was to follow in the tradition of Carnegie and Frick. Not only was he ambitious and a worker his background had prepared him for it. Coal mining was in the Ramsay blood. His father, Robert Ramsay, of whom the son once stated that he had no superior as coal mining and mechanical engineer in this country, once accounted in these words for the phenomenal accomplishments which had attached to the name "It does no harm to belong to a family of mining engineers who are just as good as any in America-if it is myself that says it." Anyone acquainted with Robert Ramsay's character realized that he was not given to overstatement. And the above-mentioned Mr. Carnegie encountered young Ramsay again, a few years later in his career, and wrote of him to young Erskine's father, that he was "going to be a credit `tae us a' " (a quotation from Robert Burns.) Nor have Mr. Ramsay's achievements been identified exclusively with the industrial field in which he early asserted himself. He has been an inventor whose techniques in mining engineering have received international recognition. As an investor of foresight, he has benefitted others immeasurably, as well as himself, being an influential factor in the upbuilding of several communities in his chosen and well-loved adopted home state of Alabama since 1887. He is a philanthropist whose benefactions have run into millions, the chief beneficiaries being educational and charitable institutions. Amidst his accomplishments the lighter side of life has not been neglected and he is known for his hospitality, his

Jan 1, 1953

By Raj K. Rajamani, Sanjeeva Latchireddi, Dave Plummer, Stieger. Julius

"The Cortez SAG mill liner design was recently modified to improve the mill operating energy efficiency. In addition to the expected benefits, the design change unexpectedly played a significant role of verifying the proposed grinding circuit expansion for the Cortez Hills project as well as illustrating current SAG mill bottlenecks. This paper will discuss the evaluation that addressed operator and maintenance observations, historical PLC data, and “crash stop” observations to calculate charge motion, packing between lifters, and slurry transport through grate and pulp lifters. The performance of the new shell and discharge end liner design will also be discussed as well as their role in the possible grinding circuit expansion.INTRODUCTIONCortez Gold Mines commenced operation in 1969 with its Mill #1 rated at a nominal 2,000 tons per day. Mill #1 was a conventional rod mill/ball mill circuit followed by an 8-stage CIP circuit. In the early 1990s the Pipeline deposit was discovered and subsequently Mill #2 was built to process the increased ore volume. Mill #2, commissioned by mid-1997, was a nominal 10,000 tons per day SABC circuit followed by an 8-stage CIL circuit for oxide gold ore. Operating and commissioning details of this plant have been published elsewhere (Powell, 1998). By late 1998, there was not enough ore volume to support both mills so the smaller, higher operating cost Mill #1 was put under its current care-and-maintenance status. A simplified flowsheet of the current mill is shown in Figure 1."

Jan 1, 2007

By S. S. Peng, C. T. Holland

Mountain Top Removal (MTR) mining started in West Virginia nearly thirty years ago. This surface mining method can extract multiple coal seams as thin as a few inches thick with total recovery and minimum rock dilution in very steep mountainous terrain. It is highly efficient even if coal seams are in close proximity and small in aerial extent. Consequently, MTR has been widely used in the Central Appalachian Coalfield (mainly Kentucky, Tennessee, Virginia and West Virginia) for the past thirty years with great success. In that respect, there has been no demand for research and little scientific research has been performed to investigate its impacts on the surroundings in the history of MTR mining. However, in the past two years the debate over the MTR mining has grown quickly and in times become very intensely. This paper describes chronologically the issues raised by various parties, legal actions, its impacts on mining permit application and research projects developed to address the issues.

Jan 1, 2000

By Reda M. Bakeer

"Measurements obtained during load testing of two steel H-piles driven at a site in Northeastern Mississippi are discussed. The general site conditions, equipment used, testing procedures and results of the pile load tests are presented. Both piles were tested in compression and one of the piles was subsequently tested in tension. The piles were instrumented with strain gauges and extensometers to measure the mobilized soil resistance and pile movement. Three different “zero strain” conditions were used to determine the mobilized soil resistance and residual loads due to driving or a load cycle. It was concluded that the effect of residual loads on driven piles could be significant. Driving residual loads influenced the magnitude and distribution of the load transfer curves more than those due to a load cycle. Results of the tension test were impacted by the residual loads from the previous compression test performed on the same pile.INTRODUCTIONSeveral factors affect the performance of a deep foundation system including the subsoil conditions, loading settings, pile type and installation method. Residual stresses develop in piles particularly due to pile driving, but they are typically not accounted for in the analysis (Fellenius 2002). Siegel and McGillivray (2009) presented an assessment of residual loads measured during load testing of instrumented auger-cast-in-place (ACIP) piles. The magnitude and distribution of residual stresses along the pile shaft and toe depend on the pile installation method, previous load cycles and time effects. Poulos (1987) reported that residual load due to driving at the pile toe is independent of pile driving equipment and may significantly affect the results of a pile load test. Hunter and Davisson (1969) reported results of pile load tests performed in compression on fully instrumented piles driven in cohesionless soils along with a discussion of the effects of residual loads. Tension loads of about 445 kN (100 kips) were measured at the pile toe after driving. Unloading residual compression load at the toe was detected as “apparent” tension since the instrumentation was zeroed prior to the test. The researchers suggested a graphical approach to obtain the “corrected” load distribution curves considering that residual load will dissipate following the tension test. Holloway et al. (1975) conducted a study on the effect of residual stresses due to pile driving and developed a computer software that accounts for residual loads. Briaud and Tucker (1984) suggested a method to account for residual loads based on the results of 33 pile load tests performed in mostly cohesionless soils."

Jan 1, 2017

By M. R. Tek, L. K. Thomas, D. L. Katz

Threshold displacement pressures are needed to determine how much overpressure can be used in storing natural gas. An experimental technique for determining threshold pressures by displacing water with gas from samples saturated with water is presented. Threshold pressures for eight low permeability samples were measured. Threshold pressure data obtained in this work, plus data on higher permeability samples reported in the literature, are correlated with porosity, permeability, surface tension and formation resistivity factor. Mercury injection pressures also were measured and correlated with air-water threshold pressures. Threshold pressures were found to be independent of time. An aerial photograph of gas emerging from the top of a core shortly alter its threshold pressure has been exceeded shows that the gas bubbles are uniformly distributed across the face of the core. Channeling will occur, however, when an increased gas phase permeability is reached, A porous medium can be re resealed alter its threshold pressure has been reached, provided it has not been desaturated below a fixed saturation. Its new threshold pressure will be lower than when the sample is 100 percent saturated with water. INTRODUCTION The degree of overpressure in excess of the discovery pressure that a gas storage reservoir can withstand is determined by the ability of its caprock to contain gas, providing the pressure does not exceed the structural limit of the reservoir. The retention of gas in a reservoir by a caprock saturated with water is a result of the capillary forces acting at the gas water interface. Without the presence of water in a caprock, gas would leak out of the reservoir at a rate determined by the permeability of the caprock to gas. The ability of a caprock to contain gas is expressed in terms of its threshold displacement pressure, which is defined as the minimum pressure needed to initiate the displacement of a wetting phase by a nonwetting phase from a porous medium 100 percent saturated with the wetting phase. The gas industry must be able to predict how much "overpressure" a gas reservoir can withstand before leakage occurs by gas displacing water from caprock overlying the reservoir. This is of economic importance since the storage capacity of a gas reservoir is proportional to its pressure. The discovery pressure for most reservoirs is found between the upper and lower limits1 shown in Fig. 1. Discovery pressures in excess of their hydraulic pressure gradient are attributed to the compaction of an isolated shale formation by the overburden.2.3 The lower limit of 0.433 psi/ft corresponds to the weight of the overburden, the gradient of the rock itself. Somewhere between

Jan 1, 1969

By Lancucki C. J, Nickson N. M

X-ray diffraction and differential thermal methods were used to determine the mineralogy of some clays used by the heavy clay industry in the Adelaide area. A detailed analysis was made of the mineralogy and particle size distribution of eighteen samples from beds in two pits in the Recent sediments in the Adelaide plains, of six white clays developed from the weathering of the Adelaide series of sediments, and of four Recent alluvial clays from a pit in the Mount Lofty ranges south of Adelaide. Structural clay products in the Adelaide area are manufactured from mixtures of these clays, so the mineralogy and particle size distribution was determined of eighteen clay mixtures used to make red bricks, cream bricks, facing bricks, pipes and tiles.Knowledge of this mineralogy is important in understanding the ceramic behaviour of the clays.INTRODUCTIONIn this investigation an account is given of the clay mineralogy and particle size distribution of some ceramic clays from the Adelaide area. The clays are used in the manufacture of structura,l clay products and the results to 'be described are part of an overall 'plan of study covering the heavy industrial clays and shales of Australia. Previous work has been published (Cole and Carthew, 1953; Ferguson, 1954; Ferguson and Hosking, 1955; Cole and Nielsen, 1958/59).In this work no attempt has been made to examine clays from all pits engaged in supplying materials for the structural clay industry. However, in 1954 the senior author collected detailed samples from two pits working in Recent alluvial clays in the Allenby·Gardens and Beverley areas near...

Jan 1, 1963

By A. Dale Wunderlich

Since Sept. 11, 2001, the author has been asked by several mining companies and mining publications to share some of his insights on how the terrorist attacks on the World Trade Center (WTC) and Pentagon might affect the mining industry globally. Until now, the author has been reluctant to express his thoughts in a publication that could possibly fall into the hands of terrorists and give them some ideas that they may not have been previously considering. However, the author discussed the contents of this article with several friends and acquaintances in the international intelligence community. They said that nothing commented on here is new to the terrorists. Potential terrorist targets Sources within the worldwide intelligence gathering community have told the author that current intelligence data indicates that it is likely that the Islamic fundamentalist groups responsible for the attacks on Sept. 11, 2001will likely be directing their effort at foreign business entities. Any overseas or any domestic businesses of highly visible companies that are part of the anti-terrorism alliance should consider themselves a potential target.

Jan 1, 2002

By James D. Nickerson

Thee Brightwater water treatment facilities, currently scheduled to be completed in 2010 and begin operating in 2011, will serve the northern part of King County, WA. The facility includes a new treatment plant and extensive conveyance system consisting of more than 21 km (13 miles) of influent and effluent conveyance tunnels and five portals. The majority of the conveyance system tunnels are mined by tunnel boring machines (TBM) and microtunnel boring machines (MTBM). Tunnel and portal construction is divided into three main contracts. The Ballinger Way receiving portal, constructed under the central tunnel contract, is the terminus for the BT-3 leg of the central contract and the BT-4 terminus of the west contract. The shaft has a 7.3-m (24-ft) finished inside diameter (ID) to accommodate removal of the central project TBM and the west contract TBM and extends to a depth of 66 m (216 ft) below grade through a complex and challenging soil profile characterized by multiple ground water tables. Vinci Grand Projects/Parsons/Frontier-Kemper Constructors (VCFK) was the joint venture team for the Ballinger Way portal. Frontier-Kemper was responsible for the shaft sinking. VCFK evaluated either slurry wall techniques or ground freezing for earth support during excavation of the portal and liner installation. The selection process took into account the vertical depth, cost, past practice, geology, water tables and a 9-m- (30-ft-) thick zone of contaminated soil at the top of the shaft. Ground freezing, which would also act as a hydraulic barrier, was deemed the better option for this project. The contract was awarded to New Jersey-based geotechnical contractor Moretrench. Typically, frozen walls, by design, key into an underlying cutoff. At the Ballinger Way portal, however, the [ ] freeze bottomed out in a substantially thick stratum consisting of predominantly clay, but with some inclusions of permeable soil that indicated significant ground water pressures. To ensure stable conditions at the bottom of the shaft, Moretrench, which also specializes in dewatering, designed and installed a perimeter array of deep wells to temporarily depressurize the permeable soils. The movement of ground water generated by pressure

Jan 1, 2009

By Jerry C. Tien

Changes and the pace of change in China’s coal industry have been extraordinary during the past several years. At least 35 of the 94 former coal bureaus have been restructured into different mining companies and groups. Some of the more productive and efficient ones were further strengthened through consolidation and expansions. And several have even formed, or are in the process of forming, strategic alliances with utility companies, railroads, ports and chemical companies to secure additional reserves and coal sales. In addition, the improvement in coal pricing during the past two years has enabled China’s coal industry to move ahead with some needed changes. Coal mining accidents, though, remain a major concern for the Chinese government. Accidents remain high even though the government has made efforts to shutdown more than 55,000 unlicensed, unsafe small coal operations throughout the country.

Jan 1, 2003

By G. Hausen, H. Micka

"Modern signal and power electronics made adjustable-speed AC drives technically feasible and reliable and economically attractive. Cycloconverters are discussed as a proven technology for mine hoists. \IntroductionUntil rather recent technical and commercial advances in power and signal electronics, DC motors were used almost exclusively for applications requiring continuously adjustable operating speeds and torques. More recently, the significantly higher efficiency and the accordingly lower operating costs of AC motors gained importance. An effective and efficient speed control of AC motors requires the control of AC voltage and frequency. Table 1 shows typical applications of adjustable-speed AC drives.CycloconvertersOf particular interest to the mining industry are cycloconverters for hoist drives. The cycloconverter represents by far the simplest, most efficient and most economical means of converting a constant-voltage, constant-frequency supply into an adjustable-voltage, adjustable-frequency supply as required for the speed control of AC drives operating in the frequency range to half of the utility frequency.Cycloconverters feeding synchronous motors or induction motors are ideally suited for slow-speed direct-coupled drives."

Jan 1, 1988

ALTHOUGH it has been a matter of about one hundred years since the idea of the internal-combustion engine entered the mind of the inventor, the practical application of its use was not attained till 1860, when Lenoir produced an engine similar to the ordinary highpressure steam engine, with the valves arranged to admit the explosive mixture and the discharge of the exhaust gases. In this case no attempt was made to compress the gas before ignition, as it was then considered that the explosion under these conditions had a detrimental effect, inasmuch as it would act as a sudden blow to the working parts. Indeed, he went so far as to inject steam and water sprays to reduce the explosion.Under these conditions the consumption of gas was exceedingly high-about 106 cub. ft. of coal gas per b.h.p. per hour but the mechanical effect showed that the engine ran in every respect as smoothly and quietly as in best steam-engine practice.The extravagant consumption of this engine was clearly pointed out at the time by Gustav Schmidt in a paper before the German Society of Engineers, wherein he states :-" The results would be far more favourable if compression pumps, worked from the engine, compressed the cold air and cold gas to three atmospheres before entrance into the cylinder. By this means a greater expansion and transformation of heat is possible."

Jan 1, 1912

By Dean Bray

During the past three years, a new rear-dumping dragline bucket technology has been patented, developed and tested at North Dakota coal mines. Field testing has shown that this new concept in dragline bucket technology can improve strip-mining efficiencies by reducing cycletimes and increasing dumping radius. This article details the process, participants and the results for the development of a rear-dumping dragline bucket. Participants in the process In November 1995, the board of directors of Dakota Coal authorized the execution of a field test and option agreement and a license agreement with the partnership of D.F. Schmidt, electrical/maintenance supervisor, and Bill Lengenfelder, president of Modern Industrial. The board also authorized entering into a dragline bucket field-testing agreement with the Falkirk Mining Co.

Jan 1, 1999

The roasting of sulphide ores and concentrates is often the first step in the production of metals or chemicals. In many processes, the production of sulphuric acid is viewed as a by-product, whereas in some plants production is an important economic factor. Regardless of the purpose, a pyrite roasting plant consists of mainly three plant sections: roasting, gas cleaning and sulphuric acid. With the addition of air, the pyrite concentrates are transformed into solid oxides and gaseous sulphur dioxide at temperatures of 600?1000°C. After cleaning and cooling, the sulphur dioxide in the roasting gas is further processed to sulphuric acid. Two types of reactors are used depending on the application: stationary or circulating fluid bed. For over 60 years, Outotec has progressively been developing the principle of fluidized bed technology in several different reactor types for a multitude of process applications. The versatility of the fluidized bed reactor system has manifested itself in the treatment of minerals, including solid fuels, and for metallurgical processes both in the ferrous and non-ferrous fields. Process applications have included roasting, calcining, combustion and charring of coals, as well as off-gas treatment. This paper provides a summary of the pyrite roasting technology currently used along with a simple cost comparison of pyrite roasting and sulphur burning processes.

Jan 1, 2009

By Leonhard Weixler

The Bauer company was founded in 1790 by coppersmith Sebastian Bauer in Schrobenhausen, a small town north-west of Munich. The original workshop business carried out works including repairs to church roofs and brew kettles. Later the company expanded its operations to encompass water pipe installation, which it continued through to the 1980s. In addition to installing water pipes it then also began drilling wells, which were sometimes constructed using very simple methods, such as tripod frames (Figure 1).

Jan 1, 2011

By Todd M. Ruff

Researchers at the National Institute for Occupational Safety and Health are investigating technologies that could be used to detect objects, small vehicles, and pedestrian workers that may be in the blind areas of haulage equipment used in mining and construction. A detection system that warns the equipment operator that there is an obstacle nearby could prevent collisions and save many lives each year. One popular technology for collision warning systems is radar. Several different types of radar have been tested in the laboratory and on mining equipment. Early in the study, questions arose concerning the best way to test radar systems. Many factors affect the performance of radar, including the size, shape, and composition of the object that is to be detected; the height of the radar antenna(s); and the relative motion of the radar system and/or object. This report discusses several different test procedures and test targets and recommends methods to determine how effective a radar system will be in detecting a person near heavy equipment.

Jan 1, 2002

By Richard F. Lynch, Frank E. Goodwin

"The development of Galfan, a new generation 95% zinc-5% aluminum-mischmetal alloy coating for steel, offers opportunities for greater fabrication flexibility and upgraded corrosion performance in automotive applications. The formability of Galfan is equivalent to that of electrogalvanized steel, based on laboratory tests and automotive component fabrication. Corrosion resistance of Galfan exceeds that of hot dip and electrogalvanized, including performance in automotive industry tests. Automotive production applications for deep drawn and stamped components in France and Germany are based on the ability to meet dual performance requirements for upgraded formability and corrosion resistance. The first U.S. Galfan application was on 1985 model Ford cars and light trucks for transmission oil cooler lines which has now expanded into a number of power steering tubing uses. IntroductionContinuing requirements for improved vehicle performance coupled with the ever present need for reduced cost have spawned the development of a number of new coated steel products. Among this new generation of coated steels is Gaifan™, a 95070 zinc-Solo aluminum-mischmetal hot dip alloy coating. Galfan exhibits particular promise for automotive use based on broad fabrication advantages and upgraded product performance(I ),The unique characteristic of Galfan is the key combination of greatly improved formability with much longer corrosion life. Galfan provides significantly better formability than any other hot dip coating. Testing shows that formability is limited primarily by the steel substrate to which the Galfan coating is applied. Galfan exhibits excellent resistance to flaking and microcracking during commercial forming operations. The result is the elimination of unnoticed damage to the coating which would show up later as premature rusting on the finished product."

Jan 1, 1987

By Arnold O. Tanner

Tables based on 1985 data, which were not available in time for publication of the "1985 Minerals Yearbook," are included in this chapter; corresponding tables for 1986 are not yet available. Raw nonfuel minerals produced in the United States during 1986 had an estimated value of $23.5 billion, an increase of $0.25 billion over the 1985 value. This is the fourth consecutive year that the value has increased, and except for a de- crease in 1982, the value each year has increased since 1971, or 14 out of 15 years. Industrial minerals growth slowed from a 3% increase in value in 1985 to a 1.5% increase in 1986, reflecting the slow growth in the domestic economy. The value of industrial minerals, more than three times larger than the value of metals, easily offset the less than 0.5% decline in the value of metal mine production. Although the decline was small, this decrease makes 1986 the fourth year in the past 6 years in which a drop in the value of metal mining production occurred in the United States. U.S. production continued to lag behind the growing world production. Overall, the estimated raw nonfuel mineral production rose 1% over that of 1985. Domestic mine production of ferrous metals declined as follows, in decreasing order of production: nickel, iron ore, tungsten, and molybdenum. All remaining domestic primary nickel and tungsten mines had closed down by yearend. Nonferrous metals that similarly declined included titanium, rare-earth metals, lead, silver, zinc, and magnesium. For the second consecutive year, aluminum, produced predominantly from imported bauxite, declined in production, while imports reached record-high levels. Somewhat modest gains were made in beryllium and copper. As has been the case for a number of years, gold was a bright spot in the domestic and internation-al metal mining industry. Gold production was spurred on by the increasing usage and development of heapleaching techniques that make lower grade ores, which were previously uneconomical, profitable. Additionally, various mining companies, the U.S. Mint, individual States, and a number of foreign countries began production of gold bullion and commemorative coins. Gold output in the United States increased from 2.43 million troy ounces (revised) in 1985 to about 3.73 million troy ounces in 1986, a dramatic 54% rise.

Jan 1, 1988