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By Daniel L. Hanson

This paper presents a case history of the design, installation and performance of a tied-back tangent caisson retaining wall which was constructed as part of the Third Harbor Tunnel project currently underway in Boston, Massachusetts. The Third Harbor Tunnel project consists of a large multi-lane transportation tunnel which is being constructed by the sunken tube method. In this type of construction, the tunnel alignment, slopes and bedding are excavated and installed underwater and the tunnel sections floated over the proper alignment and sunk in place. The tangent caisson retaining wall discussed in this paper was constructed to provide support of the upper portions of the tunnel excavation at the East Boston Portal where the tunnel exited from below the harbor and continued underground on shore. A portion of the tangent caisson retaining wall was also utilized to provide earth support for the barge unloading facility where spoil from the tunnel excavation was transferred to surface vehicles for removal from the site. PROJECT BACKGROUND The tangent caisson retaining wall was constructed by The Millgard Corporation (TMC) as a subcontractor to the Boston Third Harbor Tunnel Contractors, a Joint Venture which consisted of the firms of Morrison-Knudsen Corporation, Interbeton Inc., and J.F. White Contracting Company. The entire project team is listed below on Table 1. The design of the tangent caisson wall system was performed by Hanson Engineering, P.C. (HE) acting as design consultant to TMC. The retaining wall system incorporated a single row of pressure injected earth anchors (tie-backs) as part of the design. The earth anchors were designed and installed by Drill Tech as a subcontractor to TMC.

Jan 1, 1994

By L. A. Neumeier

The Bureau of Mines evaluated creep properties of Zn-Cu-Ti alloys that were annealed after finish-rolling either cold) or at 480° F (249° C). Compositions ranged up to 1.25 pct Cu and 0.36 pct Ti. Most data are for sheet annealed after finish-rolling to 92-pct total reduction. Annealing times were varied at temperatures between 320° and 560° F (160° and 293° C). For a number of the alloys, annealing after hot-rolling at 480° F affects creep properties very differently in longitudinal and transverse sheet directions. The detrimental result is that the anisotropy in creep properties between the two directions can be vastly increased. Conversely, specific annealing treatments of certain heavily cold-rolled alloys result in surprisingly low anisotropy in creep properties and the low anisotropy coincides with excellent creep resistance for both directions. Supplemental data are presented on tensile, hardness, and thermal expansion properties, and microstructures.

Jan 1, 1972

By Frederic M. Langevin

?? Introduction ?? LaRonde ?? History of Seismicity and Rockbursting ?? November 27th 2002 Rockburst ?? April 1st 2006 Rockburst ?? December 11th 2006 & January 11th 2007 Rockbursts ?? Seismic Risk Management Plan ?? Conclusions ?? Located in Northwestern Quebec (Can.) ?? In operation since 1988 ?? Reserves at Shafts #1 and #2 depleted ?? Production now comes entirely from Penna Shaft ?? Deepest single-lift shaft in the western hemisphere (2240 metres) ?? 7300+ tonnes per day ?? 2007 Reserves (proven & probable): ?? By-products: Ag, Cu, Zn ?? Sinking #4 Shaft (LaRonde II winze)

Feb 1, 2008

By H. -J. Langhoff

"The paper describes not a result, but a starting point to implement sustainable development to a region characterized by a typical down river landscape, agriculture, and extractive industry. The NaturFreizeitNiederrhein GmbH (NFN) is a private company with associates from administrative bodies, the local mining companies and multiple representatives of environmental protection groups (local and national), tourism organizations, cultural societies and also aquatic sport and fishing clubs. Center of the concept is the "NFN Lake District." The development concept aims to provide the agricultural industry with alternative means of income, while protecting wildlife and the ecological balance as well as preserving the social und cultural system and enhance the safety against flooding from the river Rhine. The mining industry contributes their coordination of obligation concerning reclamation and recultivation of the already existing individual projects. While designing the landscape components and establishing the infrastructure for the different tasks, the production of gravel and sand is yield as a by product. The result is a long term perspective for region and industry."

Jan 1, 2005

By John H. Johnson

Diesel tailpipe CO, C02, NO, and N02 concentrations by the Emissions Measurement Apparatus (EMA) were found to compare satisfactorily with simultaneous concentrations by instruments in the MSHA engine certification laboratory in Bruceton, Pa. The EMA was then applied to the measurement of LHD vehicle diesel tailpipe gases and smoke opacity in the White Pine and Brushy Creek Mines. A general experimental approach was developed by which instruments could be compared for the measurement of diesel exhaust pollutant concentrations in the 1/2 to 5TLV range. The concentrations are changed by varying engine speed, dynamometer load, and the portion of the exhaust which enters the dilution tunnel. Dräger detector tube diluted exhaust CO, CO2, NO, and NO2 measurements were compared with simultaneously taken portable instrument measurements. Diesel exhaust interference inaccuracies were separated from inaccuracies due to detector tube calibration by comparing the instrument readings with both actual detector tube readings and detector tube readings corrected by recalibration of the detector tubes alongside NBS traceable calibration gases. The detector tubes' accuracy was found to be only slightly affected by diesel exhaust interferences and it was concluded that most measure within certification limits established by the National Institute for Occupational Safety and Health. The effects of 2 exhaust system configurations on the pollutant concentrations in a dead-end heading were studied. Both of the configurations exhausted the gases near the roof, directing them toward the crosscut, and both improved the stratification of the air in the heading, due to the bouyancy of the hot exhaust gases. One of the configurations was a pair of Fume Diluters which diluted the exhaust with air by a 10:1 ratio, and the second system was simply a pair of exhaust pipes, bent to direct the exhaust similarly to the fume dilutors. By redirecting the exhaust, the concentration of C02 measured on the LHD vehicle was reduced by as much as 507, in dead-end headings up to 200 ft long. The Fume Diluters showed no improvement over the simple redesign of the exhaust system.

Jan 1, 1980

By Steve Klein

The Transbay Downtown Extension (DTX) in San Francisco involves the construction of a large-span tunnel with a width ranging from 43 to over 60 feet. The tunnel will be excavated using the New Austrian Tunneling Method (NATM), also known as the Sequential Excavation Method (SEM), in highly fractured and sheared rock. This paper discusses the FLAC (Fast Lagrangian Analysis of Continua) analyses that were completed for conceptual design of the tunnel support system and to develop surface settlement estimates for the evaluation of measures to protect existing buildings located above the tunnel from damage.

Jan 1, 2008

Of late there have been various papers published on this subject by various authorities, in which certain definite factors influencing slime settlement have been brought forward. As the principles set forth by these writers are of great interest, and have, in most cases, been generally accepted, the author will review them in the hope that by discussion some more knowledge may be brought to bear on many points connected with the subject.The definition of slime at the present time is not a standard one, and varies according to different authorities, some defining slime as ore crushed to such a fineness that it will pass through a screen of standard size, say 150 or 200-mesh, in water (1, 2);others as that part of the finely-crushed material which is in the physical condition which causes it to remain in. suspension in water, and possesses pr?perties which render it almost unleachable (3). Authorities seem divided on this point, but of late American writers seem to prefer the former definition. On the contrary, B L Gardiner describes slime as a mixture of small particles of crushed ore of varying sizes which, when mixed with water, tend...

Jan 1, 1912

By Gregg A. Scott, Gordon F. Revey

"The Folsom Dam is a 340-foot-high concrete gravity dam with embankment wing dams located on the American River about 20 miles northeast of Sacramento, California. Folsom Dam is operated andmaintained by the U. S. Bureau of Reclamation (Reclamation). As part of the Central Valley Project,Folsom Dam is a multipurpose facility providing water supply storage, flood control, power generation, and recreational opportunities."

Jan 1, 1999

By He Guangyi

Combining living examples, the paper introduces the controlled chamber standing shot of more than 3000t explosives initiated at one time with Nonel under complicated circumstances and the experience obtained to keep environment safe and favour mechanical rock cleaning.

Jan 1, 1998

By Alvin Kaufman

To aid industry and Government in planning water developments the Bureau of Mines in 1963 canvassed mineral producers to determine water use in 1962. Water use by the mineral industry comprises only 2 percent of the water withdrawn by industry as a whole. The major water-using mineral industries are natural gas processing, phosphate rock, sand and gravel, and iron ore. Analysis indicated the following conclusions: 1. Total water use and new water intake is dependent on the quantity of material processed and the process water requirements of the particular industry or commodity. 2. Recirculation is dependent on the processing requirements of a particular commodity, the manner in which the water is used, cooling and condensing requirements in certain large industries, the quality of new water intake, and the need to treat new and discharged water. 3. Consumed water is dependent on the quantity of water recirculated, the temperature and humidity in the area, and the proportion of water used for cooling and condensing. 4. A threefold increase in water use by the mineral industry by 1985 is forecast.

Jan 1, 1966

By Gabka T., R. E. Gregorczyk

Work to improve employees' behavior in Głogów Copper Smelter began in 2009. It has been noted that over 90% of accidents at work are attributable to human reasons. At that time, a series of external workshops was contracted based on exercises conducted by a psychologist trainer with supervisors. Having trained about 300 employees, an observation of employee behavior at workstations was started as part of the control of risk reduction measures. As a result of the above actions, the number of accidents was reduced by half between 2009 and 2017. Currently, internal workshops for communication improvement for behavioral auditors are conducted by the employees of the Smelter. Named: "I observe, react and communicate" and aimed at further mastering the elements of the safety culture in Głogów Copper Smelter. INTRODUCTION KGHM Polska Miedz is an integrated mining and smelting copper producer based in Poland and operates on the international metal market. KGHM, with annual production of over 500 thousand tonnes of copper, holds a middle position in the world ranking of copper producers. At the same time, in Europe it is the largest producer of copper from its own ore deposits, possessing its own integrated production structure, from underground mining operations to final, top-quality product. It is also worth mentioning that KGHM Polska Miedź is one of the largest Polish exporters and, apart from copper, is a significant primary silver producer in the world. The mission of our company, consistent with its strategy, is to produce copper and silver in a safe mode for workers and the environment, with reduced environmental impact. Therefore, "Głogów" Copper Smelter operations are continuously focused on the creation of safe working conditions, and minimizing the negative effects on the environment. The company meets the requirements of an Integrated Management System comprised of the following: Quality Management System ISO 9001:2008 Environment Management System ISO 14001:2004 OHS Management System according to the requirements of BS OHSAS 18001:2007 Being a proud socially responsible company, we are aware that part of an efficient OHS system is to recognize, monitor, prevent, educate and motivate, thus continuously improve working conditions for 2500 employees of Głogów Copper Smelter &Refinery. We clearly communicate that a low accident rate is beneficial for both, staff and the company, and is of utmost importance as a part of our health policy.

Jan 1, 2019

By W. J. Guay

Carbonaceous gold ores containing gold dispersed in sulfides are refractory to cyanidation because: (1 ) the carbonaceous materials adsorb gold during cyanidation; (2) a portion of the gold s so finely dispersed in the sulfide mineral lattice as to preclude contact with cyanide solution; and (3) a portion of the gold is chemically combined with carbonaceous material. Techniques which have been used to treat these ores are: (1) roasting or chemical oxidation to decompose sulfide and carbonaceous materials; (2) flotation to reject carbon; (3) the use of kerosene or other reagents to passivate the adsorptive carbon compounds; (4) carbon or resin in pulp; (5) flotation of a bulk concentrate which is treated by one of the above methods; and (6) the use of chelating agents which have a stronger affinity for gold than the activated carbon in the ore.

Jan 1, 1981

Despite the wealth of information available on phase equilibria of oxide systems there remainmany gaps and inconsistencies in our knowledge base. From an industry perspective there is anongoing need to adequately describe the phase chemistry of slag systems in order to optimizeprocess performance and improve productivity. Since this chemical behaviour cannot be predictedfrom first principles it follows there is also an ongoing need for accurate experimental data. The advances made in recent years in the capabilities of sophisticated analytical and measurement equipment have made it possible to develop new experimental techniques for the direct determination of phase equilibria in low order and complex multi-component slag systems. In addition the development of powerful computer modelling tools makes it possible to provide more comprehensive descriptions of the phase chemistry, to present the information in a range of perspectives, and to critically analyse the various types of related thermodynamic and structural information available. This review provides an overview of the types of information that can be used to determine phase equilibria in slags systems, analyses the influence of uncertainty and the relative importance of these types of data, and describes the advantages and limitations of the various experimental techniques that can be employed to obtain this information. Examples of recent studies are provided that demonstrate how an integrated approach to the determination of phase equilibria in complex systems, involving the use of targeted experimental studies and systematic thermodynamic model development, can lead to a better utilization of our current research capabilities and resources and more accurate descriptions of these systems. Keywords: slags, phase equilibria, experimental techniques

Jan 1, 2004

By R. H. Grau, R. B. Krog

The National Institute for Occupational Safety and Health (NIOSH) has investigated the unique ventilation requirements of large-opening mines to help identify and evaluate the effectiveness of various fan types to improve the ventilation and air quality in the underground workplace. Large-opening mines, with their low airflow resistance factors, can be ventilated with free-standing auxiliary fans because airflow pat-terns in these mines are primarily controlled by airflow momentum. The flow characteristics of both vane-axial and propeller fans were investigated and tested at four large-opening mines to assess the effects of fan location on recirculation and entrainment. Each fan type has its own airflow, entrainment and penetrating air-flow characteristics, and operating costs that are advantageous for specific applications. Either fan type can be used for most auxiliary applications. However, this research has shown that the optimum placement and use criteria for propeller fans differ from those promulgated by the U.S. Bureau of Mines (USBM) for vane-axial fans Brechtel et al. (1985)

By Klaus Pöllath

The Netherlands RandstadRail project makes use of a large range of sophisticated geotechnical techniques to allow a shield driven tunnel to approach the central station of Rotterdam. This paper describes the construction of three deep excavation pits constructed with 1.2 m and 1.5 m thick diaphragm walls. Besides the presentation of the actual diaphragm wall activities special consideration is given to the break-in and break-out situations of the TBM into the deep excavations pits using sealing blocks and partly glass fibre reinforcement in the diaphragm walls.

Jan 1, 2006

By John C. Machisak

The National Safety Competition is sponsored and conducted annually by the Bureau of Mines, U.S. Department of the Interior, to give greater impetus to the building of programs safeguarding the employees of the mineral industries from disabling work injuries. The results of the 1960 National Safety Competition are presented in this publication. Mines and quarries that were awarded the Sentinels of Safety trophy for the best safety record in their competitive group and those mineral operations that ranked second, third, fourth, and fifth in the competition are listed with a summary of their achievements in preventing disabling work injuries. In addition, this publication presents statistical data on disabling work-injury experience in all other mines and quarries participating in the annual competitions.

Jan 1, 1962

By André Laplante, Robert C. Dunne

"The role of flash flotation in precious metal recovery is reviewed. Interacting flash flotation and gravity recovery is discussed. The GRG test can be used, when linked to the behaviour of gold in grinding and classification units, to predict the recovery of GRG by flash flotation. The Cadia mill in New South Wales is used as a case study of circuit design, performance and simulation. It is shown that high throughput coarse grind applications such as Cadia require very effective fine GRG recovery systems in the primary grinding loop, which are more consistent with flash flotation than batch centrifuge concentrators (BCCs). BCCs can effectively recover a significant fraction of the GRG from flash concentrates, as predicted by laboratory testing and confirmed at a growing number of mill sites.INTRODUCTIONThe GRG test was designed to characterize Gravity Recoverable Gold (GRG) ten years ago (Woodcock and Laplante, 1993; Laplante et al, 2000), in response to the need to predict how much gold could be recovered from the main circulating load of grinding circuits using centrifuge concentration. The amount of GRG is not itself a prediction of gravity recovery: the performance of a gravity circuit nested in a circulating load also depends on the type and size of unit used, how much of the circulating load is treated, and how many times GRG is recycled and presented to the recovery circuit. The GRG test was first used in a simulator to predict gravity recovery (Laplante et al, 1995), and indeed most of the early tests targeted ores or prospective ores for which gravity recovery was an obvious match. As the test became more accepted, more and more samples returned a verdict that precluded the use of gravity recovery, or made it marginal. Typically, such ores are either copper-gold or base metal ores in which the GRG content is often fine (largely below 105 um) and ranges from 8 to 33%. Extensive simulation and plant sampling tests, either published (Laplante et al, 1997) or proprietary, show that full scale gravity recovery for these applications is generally below lo%, and can be as low as 2%. Not in all cases are such low recoveries economically unjustifiable, since there is documented evidence (Darnton et al, 1992) that a significant proportion of the gold recovered, at least in the case of base metal ores, would not have reported to the copper or zinc concentrate and received NSR credits."

Jan 1, 2002

By John Rusnak, Christopher Mark

Point load testing is used to determine rock strength indexes in geotechnical practice. The point load test apparatus and procedure enables economical testing of core or lump rock samples in either a field or laboratory setting. In order to estimate uniaxial compressive strength, index-to-strength conversion factors are used. These factors have been proposed by various researchers and are dependent upon rock type. This study involved the extensive load frame and point load testing of coal measure rocks in six states. More than 10,000individual test results, from 908 distinct rock units, were used in the study. Rock lithologies were classified into general categories and conversion factors were determined for each category. This allows for intact rock strength data to be made available through point load testing for numerical geotechnical analysis and empirical rock mass classification systems such as the Coal Mine Roof Rating (CMRR).

By Y. El-Mossallamy

The piled raft foundation was extensive applied in the last two decades in different soil conditions e.g. in soft to stiff clay as well as in medium to dense sand and even in highly weathered rock. The piled raft is now applied not only to control the foundation settlement but also to minimize the required raft thickness to reach the most economic foundation design. An innovative application of the piled raft is its special adjustment to cases of foundations with large load eccentricities or very different loaded parts of buildings to avoid the need of settlement joints, which are especially complex below ground water table. Recently, the piled raft is applied for foundations of highway and railway bridges with special serviceability requirements regarding the allowable total and differential settlement as well as tilting. Actually numerical analyses are the mostly used design methods for piled rafts. For all day design practice a simple and modest design method is highly needed -at least in the first design stage- to check the feasibility of the piled raft on the specific project conditions. In this paper, a general overview on the recent innovative applications of piled rafts in Germany will be presented in a short overview. The results of the simple design method will be discussed and compared with the results of more enhanced numerical methods.

Jan 1, 2006

By R. Gensemer

A number of state and federal agencies are calling for development of aquatic life criteria for conductivity. These aquatic life criteria or ?benchmarks? are based on observed correlations between conductivity and benthic macroinvertebrate community composition, generally measured by composite metrics or indices. However, development of an aquatic life criterion for a composite variable like conductivity is made difficult by a number of factors. Based on a database from West Virginia, observed patterns of invertebrate community composition versus conductivity may instead be related to a combination of abiotic (e.g., ionic composition, habitat) and biotic (e.g., life history, colonization potential) factors. Many benthic invertebrate taxa also do not respond to increasing conductivity in a consistent relationship. Many states have determined that a composite variable, like conductivity or TDS, is not appropriate for criteria development, as many studies have shown that toxicity varies as a function of ion composition and can be mitigated by elevated hardness. We conclude that the relationships between conductivity and changes in benthic macroinvertebrate community composition are neither strong nor reliable enough to warrant derivation of a criterion based solely on conductivity.

Jan 1, 2011