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By Erica E. Hall, Robert H. Peters, Charles Vaught, Jon C. Volkwein

Coal workers’ pneumoconiosis is the leading cause of death due to occupational illness among U.S. coal miners. This disease is caused by miners’ exposure to excessive levels of respirable coal mine dust. A personal dust monitor (PDM) has recently been developed to provide near real-time feedback to miners regarding the level of respirable coal dust in the air they breathe. The main objective of this report is to document coal miners’ reactions to this device and how they make use of the information it provides. It summarizes a field study by the National Institute for Occupational Safety and Health that documented the opinions of 30 miners at 4 underground coal mines concerning the use of PDMs.

Jan 2, 2008

Largely inherited from the past and from strictly internal laboratory use, the certification of reference material using round-robin assaying is often insufficient for the use made today for external assay laboratory control by client parties. Certification often needs to be revisited on the basis of existing round-robin data, especially to derive reproducibility parameters to the end of establishing probabilistic performance gates for operational error detection on a batch per batch basis (ie batch-ærejectionÆ). The most common difficulty arises when only a few certification samples have been analysed in one single batch by each laboratory, so that the round-robin data do not contain the full variability that needs to be quantified. Existing certification data sets from properly submitted round-robin samples were studied using analysis of variance to derive a remedial method, leading to the proposal of default correction factors to restore full variability estimates when no other avenue is available.

Jan 1, 2008

By Stephen Hughes

Ausmelt Top Submerged Lancing (TSL) Technology has gained widespread commercial acceptance in the lead and zinc industries, as an efficient and highly flexible pyrometallurgical reactor with accompanying excellent environmental performance. For the processing of lead and zinc bearing feed materials twenty one (21) Ausmelt furnaces are now in operation, under design or under construction. With recent increases in the value of both lead and zinc and an ever increasing focus on the sustainable use of resources, interest in the processing of secondary feed material sources as well as metal containing residues has substantially increased. Ausmelt Technology has proven to be well suited to the economic recovery of values from such sources. This has for example culminated in Ausmelt?s commitment to the Whyalla Zinc project as the owner/operator of a facility for the treatment of zinc bearing secondary feeds. This paper describes Ausmelt?s recent developments in the fields of lead and zinc processing, as well as further investigations into new processing areas, including the direct smelting of zinc concentrates. Ausmelt?s TSL Technology can now be regarded as Best Available Technology (BAT) for metal production.

Jan 1, 2008

By Amy B. Cerato

The application of this study is to use helical anchors as a foundation system for small wind tower (1 ? 10 kW) guyed cables. Helical anchors are currently used to anchor guyed cables of telecommunication and electric towers. However, the increased dynamic vibrations a wind turbine adds to the tower and foundation system under working loads, as well as extreme environmental conditions (e.g., straight line winds, ice load or sudden furling shocks), require additional knowledge about the behavior of helical anchors. These field conditions were simulated in this study by instrumenting a working tower with load cells and 3-axis accelerometers to gather data on wind speed and tower response. These tower responses were then transmitted to the helical anchors through an extensive, large-scale testing program that included monitoring the performance of the helical anchor foundation under dynamic loads, subject to natural variations in both wind regimes, precipitation (water level) and variations in helical anchor geometry. This paper specifically discusses the effects of helical anchor geometry on helical anchor performance under long-term dynamic loads.

Jan 1, 2008

By Joel L. Volterra

Since 1910, Mueser Rutledge Consulting Engineers (MRCE) has regularly provided professional engineering services including inspection of pile load tests. Historically, such services included on-site inspection of the driving of test piles and subsequent static load tests by qualified Geotechnical Engineers. Load testing procedures are specified by local or State Building Codes, locally the 1968 Building Code of the City of New York (1968 BCCNY). Between 1968 and 2008, the 1968 BCCNY required a minimum 48-hour hold period for standard loads per pile type, an extended 96-hour hold period for higher capacity piles, and a settlement criterion that the pile maintain a test load equal to two times the design load with less than 0.012 inches of settlement over the last 48 hours of the hold period. Effective July 2008, the new 2008 BCCNY shortened the hold period and relaxed the settlement criteria to that which is more similar to other governing codes and standards such as the International Building Code (IBC 2006) and the American Society for Testing and Materials (ASTM). MRCE implemented an automated load test monitoring system to reduce costs and to alleviate or minimize overnight and off-hour staffing for load test readings. Initially, a series of linear variable differential transformers (LVDTs) and data loggers were included in the Contractor?s load test setup to electronically record pile head settlement and where applicable, settlement of telltales installed to varying depths in the pile. A pressure gage was subsequently added in the hydraulic line, then a load cell, strain gages, and remote access using modems. The ease of the setup and modular adaptive nature of this system have proven it to be a useful tool and improved our ability to better serve our clients and manage our pile load testing services.

Jan 1, 2008

By J. M. R. Carvalho, M. T. A. Reis, M. R. C. Ismael, M. J. N. Correia, S. M. C. Santos, J. M. Carvajal

A sulphide zinc concentrate (Zn-40%) has been leached in sulphuric and chloride media to optimize the conditions for the recovery of zinc and copper. Previous results showed that extractions of 95% zinc and 20% copper can be achieved in just one stage, after two hours of leaching at 80°C with a solution 0.5M in Fe2(SO4)3 and H2SO4 and a solid/liquid ratio of 5%. This work presents the results obtained in the leaching experiments carried out in sulphuric and chloride media using two and three crosscurrent stages and a countercurrent process simulation for a solid/liquid ratio of 10%.

Jan 1, 2008

By Michael Lane

With the success of their existing casino operation on the Ohio River in Lawrenceburg, Indiana, the Indiana Gaming Co., LP planned a major expansion of the current facilities. This expansion includes a second 1400+/- car parking garage, a new surface parking lot, elevated walkways, and a new floating casino that will double their present square footage and consolidate all of the gaming activity to one floor. In March of 2006 Richard Goettle, Inc. was awarded the general contract to construct a 260? x 520? boat slip for the new Argosy VII floating casino. An Open Cell® bulkhead system was specified as the means for constructing the new slip. Our contract included the purchase and installation of 300,000 square feet of PS27.5 sheet pile, excavation of 230,000 cubic yards of soil, and a 3300 square foot Mechanically Stabilized Earth wall.

Jan 1, 2008

By A. F. Usov

"The use of the Electric Pulse Discharge method of materials destruction (EP) for disintegration of materials in an industrial-waste processing are examined. The principles and Experience of the development device of EP-disintegration have been described, the technological efficiency of disintegration of industrial minerals estimated.IntroductionThe Russian scientists have proposed and comprehensively studied the electric pulse (EP) technique which is applied in ores and materials disintegration [1, 2 ]. The different aspects of the problem have been presented by the authors in papers at many international congresses [3-6]. Recently the technique is intensively developed in many countries, and various disintegration installations are exhibited.Crashing and disintegration of ores by EP-method is characterized by high selectiveness of destruction. It provides better disclosure of mineral grains and prevent it from destruction. EPmethod reduces slurry formation. All this provides better mineral extraction at ore beneficiation and improves concentrate quality. It also prevents the product from polluting with equipment metal, inwall and grinding equipment material. The possibility to change the character of dynamic loading allows controlling grain-size composition and getting small-size product in contrast to mechanical method of crashing.The product of EP-crashing is characterized by less toughness and greater specific surface area of grains since the new surface is formed at splitting and chinks extension. The product is of high sorption and reactivity in chemical changes. Open grains of mineral spots correspond to their natural condition and it is of great importance for studying mineral.The principles of the development deviceLong-term studies of the technique carried out by research institutes such as Research Institute of High Voltages (Tomsk), Kola Science Centre of RAS (Apatity), Institute ""Mekhanobr"" (S.Pertersburg), made it possible to substantiate principles of the disintegration installations design, make exploratory stands and technological installations to carry out pilot tests and operations under production conditions. The construction design of disintegrating installations depends on many technological and physical factors. Of all the technological factors, the most significant one is to preserve the liberated product because it is the peculiarity of the EPdisintegration to have high selectivity of disintegration. The preservation of the mono-mineral product liberated from the rock mass means that this product is not overgrinding, which causes the loss of the product with slime in processing, and that the initial natural form of the mineral inclusion is also preserved because it is the size and the integrity of crystals that determines its cost value (precious minerals). On the one hand, it is provided by a stage disintegration technique, with the product classified after each stage, and, on the other hand, by selection of specific conditions of electric breakdown, which ensure high performance of electric breakdown and effective disintegration of material fragments, with the useful mineral inclusions preserved intact, with its size considerably exceeding the discharge gap. These conditions are provided by the appropriate geometry of electrodes, the discharge gap and the screen size due to the material’s nature and grain size."

Jan 1, 2008

By R. Harrisson, K. Esmaieli

Brunswick mine employs an ore and waste pass system for material transfer. This paper reviews the evolution and performance of ore pass systems at the mine. It presents the range of selected configurations, inclination, dimensions, etc. Select case studies are used to address the influence of structure, stress and materials handling on the longevity of the employed ore passes.

Jan 1, 2008

By Bruce Richardson

A contractor-manufactured 4.75m (15'-7") diameter EPB shield excavated a 115m (375 ft) long tunnel under the San Antonio River as part of the Salado Creek to Dos Rios Pipeline Interconnect Project in San Antonio, Texas. Lignite, limestone concretions, and sandstone in the face of the tunnel required the use of disc cutters. Less than 7.6m (25 ft) of sand and gravel hydraulically connected the top of the tunnel to the channel of the river. Fully lagged steel ribs with filter fabric were used for initial ground support and water control. This and other contractor manufactured TBMs in the 1.2 to 4.75m (4 to 16 ft) range are presented with descriptions of the jobsites, equipment, performances, and problems.

Jan 1, 2008

By Sung-Joo Lee, Gi-Chon Han, Nam-Il Um, Hee-Chan Cho

"In Korea, almost all of bottom ash produced by coal power plants is disposed of in ash ponds. Ash storage areas comprise more than 80% of most coal power plant sites. This disposal method is causing environmental problems and a managerial burden for plant operators. In this study, investigations to develop a beneficiation process for separating coal pond ash into various products were undertaken. To improve efficiency of the separation, coal ash was separated by sizes and each size fraction was subject to various beneficiation processes. The separation process used were flotation (-200 mesh size), hindered settling (16x200) and tabling (16x200 and 8x16 mesh). The results showed that various marketable products, such as lightweight aggregate, sand, high-carbon fuel, could be recovered from coal pond ash using simple physical separation techniques.IntroductionDue to the increased use of coals every year, about fifty million ton of coals were used in 2007 alone. As a result, about 6 million tons of coal ash were generated. In Korea, the coal bottom ash is classified as a general industrial waste and is usually disposed of in ash ponds. The costs for this disposal method continue to increase due to rising costs of site management and development and more strict environmental regulation. Therefore, utilities are constantly looking for ways to increase utilization of coal ash. In this study, various beneficiation processes were evaluated to examine the possibility of separating coal pond ash into various products which can be used as aggregates and high-carbon fuel."

Jan 1, 2008

By Julian Malnic

The nascent marine mining sector appears to be now at a point of critical mass with the prospect of mining seafloor massive sulphide deposits at some time in the coming few years an inevitability. Julian Malnic makes comments from his experience base as an entrepreneur and founder of Nautilus Minerals Inc. in 1995 and will speak from an independent viewpoint of the commercial setting of the status quo of the proto-industry and the major factors likely to have major influence over its future. The presentation questions these factors and the role they will play. Do we need metals from the oceans? Understanding the competing and established terrestrial sources of each commodity is essential in comprehending how a marine competitor can profit. What are the rates of discovery for marine minerals? At what point will marine explorers start to impact the terrestrial copper and zinc exploration sector? The advance of technology is important in finding, imaging and mining SMS deposits, but which new technologies offer the advantage to mining in the ocean and which to mining on the land? Several competitors have now joined Nautilus as competitors to this global pioneer of SMS exploration/production. The membership of the major miners in the marine sector is growing steadily with important relationships developing but many have not put a toe in the water yet. A path of increasing width is opening to commercialization of SMS miners but crusts and nodules, as bearers of copper ? also found in SMS, and nickel ? also found in widespread nickel laterite deposits on land, are unlikely, in this perspective, to be winners this century unless highly valued minor metals are targeted.

Jan 1, 2008

By Bora Derin, Onuralp Yucel, M. Seref Sonmez, Murat Alkan

"Latest stage in the production of boron carbide by metallothermic methods using magnesium was the leaching process. Boron carbide particles obtained by self-propagating high temperature synthesis contained several impurities such as magnesium oxide and magnesium borates after the metallothermic reactions. Removal of such contaminates by hydrometallurgical methods required to produce high purity boron carbide. Leaching by concentrated hydrochloric acid solutions resulted in the production of pure boron carbide together with high magnesium and boron containing solutions. Removal of such ions from the spent liquor was the necessity to have dischargeable solution. In this study, precipitation of magnesium and boron compounds from relevant chloride containing spent liquors and the production of saleable products was aimed. The effects of chemical reagents, pH of the solution on the precipitation efficiency of magnesium and boron compounds were investigated in the study. Chemical analysis and the characterisationof solid phases by using x-ray diffraction analysis were the latest stage.Introduction A variety of advanced ceramics, inter-metallic, organic and inorganic compounds, oxygen free single crystals, and polymers can be synthesized by using different SHS techniques [1, 2, 3]. In the SHS process, after initiation, reaction becomes self-sustaining and propagates in the reactant mixture. A high amount of heat which is generated during the process accelerates the reaction rate and thus it makes the process highly productive and economically feasible for different production scales. After the SHS process obtained powder mixture needs to reacted with acidic solutions to purify the product. In this case B2O3 was reacted together with C and Mg to synthesis fine B4C powder resulted in the production of MgO as well according to the Eq. 1 and then MgO was removed from the mixture by leaching with the concentrated HCl solution as shown in Eq. 2, respectively [4, 5]."

Jan 1, 2008

By Harvey W. Parker

Our industry has developed to the skilled, experienced and productive industry that we now enjoy as a result of the visions of great engineers throughout history, but, in particular for their visions in the last 1 centuries. Unfortunately for our forefathers, the technology lagged so far behind that these exceptional visions could not be realized for decades, sometimes for a century. All that has changed in recent time and many bold and visionary projects can now be constructed and operated because of dramatic advances in technology. Before, say, 1950, tunnel technology developed very slowly. However, technology is now developing at such a fast rate that planners and decision makers are challenged to stay ahead. Moreover, new technology will develop during the lifetime of any project that can dramatically improve under-ground space projects. One of the best examples of this technological advancement is that of closed-face TBMs which now make tunneling feasible in previously impossible ground conditions. Since it usually takes a decade or more to plan, overcome environmental and political issues, construct, and put into service major projects, planners and designers are challenged by the changes in technology that occurs during the long time span of planning and construction. This is particularly true of large infrastructure projects such as transportation, water and wastewater systems and other major underground schemes. Also, since the serviceable life of many of these tunnels is often over one century, planners must consider not only lessons learned from the past but also what new concepts and innovations may develop over an extremely long time. These and other issues create a great challenge to planners and illustrate the great importance of careful but creative vision and flexibility during planning of long-term tunnel and underground space projects.

Jan 1, 2008

By Peter G. Chamberlain

Novel and innovative mining methods are attracting the attention of mining engineers at an unprecedented level. Historically, the US mining industry has responded rather conservatively to new technology. The financial difficulties affecting the domestic mining industry in the early 1980s changed attitudes toward new technology. The market contraction during that period, coupled with an expanding world mine capacity, created a serious oversupply of many raw mineral products. Many mining companies found that retaining a share of world markets while making a profit required drastic cost-cutting measures.

Jan 1, 2008

While the United States and the rest of the world struggles with record-setting oil prices Canadian oil sands producers are ramping up production to meet demand for oil while also fighting against a host of negative images. In recent months, the price of oil has skyrocketed. Most of that oil comes from Saudi Arabia. In Alberta, Canada there are unconventional oil reserves that rival those in Saudi Arabia in the vast Canadian oil sands, sometimes called the tar sands. Proponents of the oil sands say that Alberta?s oil sands can be a secure source of oil and energy for the United States for many years to come. With new mining and drilling projects, the industry has said that it could quadruple its production to nearly 4 million bbl/day by 2020. Time magazine once called the oil sands, ?Canada?s greatest buried treasure that could satisfy the world?s demand for petroleum for the next century.? So why hasn?t the United States embraced this close, politically secure source of energy? Because, getting usable fuel from the oil sands can be a dirty business, say opponents. The oil sands are a combination of clay, sand, water and bitumen. It is a heavy, black, thick oil. Oil sands can be mined and processed to extract the oil-rich bitumen, which is then refined into oil. The bitumen cannot be pumped from the ground in its natural state. Instead, tar sand deposits are mined, usually using strip mining or openpit techniques, or the oil is extracted by underground heating with additional upgrading. These methods require a huge amount of energy and water and produce a large amount of carbon emissions. Environmental groups that have long spoken out against the oil sands projects got some political backing in the United States in June when a group of mayors from large U.S. cities spoke out against the oil sands, as did presumptive Democratic candidate for U.S. president Barack Obama?s senior energy advisor. During a convention of large-city mayors in Miami, FL, Alberta?s oil sands were singled out in a nonbinding resolution calling for national guidelines to track the lifecycle impact of different types of fossil fuels. The resolution urges cities not to use unconventional sources of energy with a large carbon footprint, such as liquid coal and oil shale and oil sands.

Jan 1, 2008

By K. Kashiwaya, N. Hiroyoshi, H. Furuya, N. Sumiya, M. Tsunekawa, M. Ito

"The number of hybrid vehicles is increasing and this is causeing an increase in waste nickelmetal hydride batteries. The cathode activating agent of batteries is made of nickel hydroxide and the anode activating agent is an alloy of nickel and rare earth elements. Conventional rotary kiln methods cannot recover the rare earth elements, and hydrometallurgical treatment of crushed product consumes large volumes of agent. The physical separation of the anode alloy from the cathode hydroxide would make it possible to reuse the alloy. The authors have reported separation of anode and cathode components in the large size fractions using a newly developed dry magnetic separation method. Wet magnetic separation has been applied to the powder fraction and about 90% anode purity was achieved. This paper reviews experimental results from previous publications and proposes an integrated treatment process for crushed nickel-metal hydride batteries.IntroductionEnvironmentally-conscious clean energy vehicles have attracted much attention in developed countries and particularly hybrid vehicles are increasingly mass-produced as low emission vehicles. Hybrid vehicles have both a gasoline engine and an electric motor to save on gasoline usage and a nickel-metal hydride battery is used to store electric energy. The battery contains Nihydroxide and Co as the cathode activating agent and an alloy of Ni and mischmetal (mM), a rare-earth element mixture consisting of La, Ce, and Nd, as the anode hydrogen adsorption component. In conventional recycling, the Ni and Fe are recovered with a rotary kiln-electric melting process and the Co and mM go to the slag component [1] and hydrometallurgical treatment of crushed product consumes large volumes of agent. Japan Oil, Gas and Metals National Corporation have proposed a low energy and low cost recycling treatment process combining the physical and chemical treatments and the authors are investigating the physical treatment process."

Jan 1, 2008

By G. G. Richards, Y. Oyediran, V. Chow

The oxygen softening process for partial removal of arsenic and antimony from lead bullion has been in use at Teck Cominco's Trail smelter since 1986. In this process, industrial oxygen is injected into bullion to remove As and Sb with the formation of an oxide slag. In Trail, the levels of these elements are reduced to concentrations suitable for processing in the Betts electrorefining plant. Recent moves toward the treatment of higher arsenic-bearing feeds have necessitated an increase in the process capacity to meet the specifications for drossing plant bullion. Process intensification trials were conducted in-plant to develop an operating strategy for higher bullion processing rates. This was preceded by a study conducted with McGill University to develop a fundamental understanding of the therm ochemistry and kinetics of the process. The results have yielded more effective control of the operation, and identified opportunities for further improvements.

Jan 1, 2008

By Qixing Yang, Björn Haase, Fredrik Engström, Anita Wedholm

"MiMeR, the Minerals and Metals Recycling Research Centre at Luleå University of Technology, Sweden, started industry-related research work to stabilize an EAF slag from Höganäs AB with of CaO/SiO2 values near to 3.2. The intention was to determine the suitability of the EAF slag as construction material after stabilization. Some of the stabilizers effective for preventing disintegration of AOD slag were examined in laboratory tests for stabilization of the EAF slag. The EAF slag samples were mixed together with stabilizers for melting at 1600ºC and then cooling in a crucible system. With a laboratory granulation system, the liquid EAF slag was cooled rapidly using air. Samples from the tests were characterized by different techniques, including XRD and SEM. Some of the results from the work may be useful for preventing slag disintegration and, thus, enhancing utilization of the EAF slag as construction material, thereby saving valuable natural resources.IntroductionAt steel plants of some MiMeR member companies, steel grades with low carbon contents were produced in Electric Arc Furnaces (EAF). EAF slag was tapped out of the furnace to slag pots for transport to slag yards, where the slag was poured on the ground. Very often, the EAF slag disintegrated during cooling on the ground. Fines from the slag disintegration were often difficult to handle and use as material for road construction [1, 2]. The EAF slag disintegration was rather similar to the disintegration occurring in the slag tapped from some AOD (Argon Oxygen Decarburization) converter heats.Literature studies show that formation of dicalcium silicate (C2S) is the main reason for the disintegration or dusting of AOD slag from production of stainless steel [1-4]. The C2S can form while the content ratio of CaO to SiO2 of the slag, CaO/SiO2, exceeds 1.4 [1]. Values of CaO/SiO2 for the AOD slag are often near to 2.0, making the C2S a predominant slag component. The ß phase of C2S, ß-C2S, transforms into its low temperature ? form in the temperature range of 400-500°C, inducing a volume expansion of nearly 12% [1-4]. The volume expansion disintegrates the AOD slag."

Jan 1, 2008

By Steven W. Hunt

Appropriate seals, portal ground improvement, and compatible shaft construction techniques are vital elements for launching and receiving tunnels effectively in urban areas where adjacent property requires protection from excess ground movements. This paper focuses on seals and ground improvement along with shaft wall types, required to launch or receive tunnel boring machines within wet, permeable ground at the portal zone. The paper also discusses probing to verify suitability before the tunnel eye is cut. Methods addressed include: rubber gasket seals; soft eyes; double walls; top hats for reception; and, portal zone ground improvement (permeation grouting, jet grouting, un-reinforced slurry diaphragm wall panels, ground freezing, deep soil mixing, dewatering, and over-excavation and backfilling). This paper focuses on challenges with launch and reception of pressurized-face TBMs with precast concrete segment linings. Challenges related to pipe jacking are discussed in a separate paper titled ?Mitigating Microtunnel Launch and Reception Challenges? (Hunt and Finney 2008).

Jan 1, 2008