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The Environmental Session will consist of five papers dealing with various aspects of trace elements associated with coal. Analytical procedures to determine the amounts of trace elements will be discussed. Other papers will deal with trace elements in streams downstream from coal mines, potential pollution from wastes from coal preparation plants, potential recovery of trace elements, and potential pollution from trace elements as a result of the combustion of coal.

Jan 1, 1979

The Acid Leaching Process for the Synthesis of Zeolitic Material from Paper Sludge Ash

Sep 13, 2010

By C. Y. Liu

This paper principally deals with the application of caisson foundation in the Chinese bridge building industry, the different types of caisson foundation adopted, and their spheres of application. Caisson foundation has been used and speedily developed for bridge works in New China, and a number of new innovations have been made in its design. Especially in deep water foundation, the Nanjing Bridge over Changjiang has attained one of the deepest bridge foundations in the world. There are six types of deep caisson foundation being now in use in China, namely:

Jan 1, 2010

By Dave Minney

The South African mines health and safety regulations require that mine management establish a quality management system for rock support material. Quality control of resin capsules used as a support medium in South Africa is specified under SA National Standards No 1534. Experience has shown that this specification, while addressing the chemical and physical aspects of the products, but does not address the required performance criteria. In order to address this shortcoming, the industry has put a lot of emphasis on short encapsulation pull tests, performed insitu, in the underground workings of the mine. This is also fraught with many shortcomings, particularly as regards site availability, cost and repeatability of results. To try and address these issues, the Department of Mechanical and Aeronautical Engineering at Pretoria University were approached to develop equipment and machinery that could produce reliable, repeatable results in a laboratory environment which reasonably simulates installation practice underground. The test method is based on the ASTM F432-95 Strength Index test, but modified to use push test rather than pull tests. The paper describes development of the test method and the preliminary results and findings of the work.

Jan 1, 2007

By E. C. Lee

THE safety of mine workers has received more attention from both State and Federal law-making bodies than any other industry, a fact that shows clearly the hazardous nature of the industry. The last, but by no means the least, of the measures adopted for the protection of mine workers, is workmen's compensation legislation. This is proving to be a powerful instrument for greater safety in the industries, from the fact that special stress is laid not on how the accident happened or who may have been responsible for it, but on how badly the employee is hurt by it. The injured person does not have to employ lawyers to prove his case, because the mere fact of his employment is proof of his right to compensation. The immediate effect of such legislation is the certainty confronting the mine operator that he must pay out large sums for every accident, regardless of its cause, thus adding materially to the cost of the production of his coal. This fact furnished to the operator the strongest incentive to reduce the causes of accidents; not that the operator has ever lacked reasonable consideration for the welfare of his employees and a proper humane interest in their safety, but his engrossment in earning his daily livelihood has been so great that he has not felt that he had the time to devote to the safety of the operation. This time he must now find because of the actual-cash value of the prevention of accidents in his mines. This agency alone proved inadequate to bring about a material improvement because operators have always been willing enough to improve safety conditions when possible to do so within reasonable limits of their financial ability. The requirement in the Workmen's Compensation Laws of several of the States, that the mine operator shall insure as a guarantee of his ability to meet his compensation obligations, has furnished the needed incentive, moral and financial, necessary to the prompt and effective dissemination of a more general knowledge of the causes and

Jan 10, 1917

Two miners were fatally injured when a pillar bump occurred during retreat mining in a southern West Virginia coal mine. The mine was operating in the Eagle seam with overmining in the No. 2 Gas and Powellton seams. A coal bump is defined as a sudden and violent failure of coal caused by the release of stored strain energy in the pillar. While significant strides have been made by academia, industry, and regulatory agencies to better understand bump conditions and mitigation techniques, coal bumps represent a long standing, highly site-specific engineering problem in which the exact failure mechanism(s) is not clearly understood.

Jan 7, 2020

By Luciano B. Oliveira, Alexandre M. Stumbo, Luis G. C. Marques, Valdo S. Marques, Sergio N. Monteiro

"Similar to the ethanol program, initiated more than 30 years ago, the recently created biodiesel program in Brazil is expected to rely on private initiative based on agribusiness for vegetable oil production. Campos dos Goytacazes is a large county in the northern of the state of Rio de Janeiro with land still available for oily vegetables plantation in addition to the land traditionally occupied by sugar cane plantation, which is used to produce ethanol. In order to extend the biodiesel program to Campos dos Goytacazes, the State University of Northern Rio de Janeiro (UENF) is conducting a technical project for the development of the infrastructure for biodiesel production. In this work, the infrastructure based on versatile equipment for biodiesel esterification built in the Center for Alternative Energy of the UENF is presented.IntroductionBiofuels are gaining worldwide attention as a possible economical solution for the prediction of declining reserves of petroleum and related increase in price of barrel. However, nowadays, a more relevant question is the climate changes caused by burning fossil fuels. This is especially the case of coal and petroleum based fuels, mainly gasoline and diesel that propel the majority of vehicles and generate a large amount of CO2 emissions responsible for global warming. This combination of economical an environmental problems is already providing a strong motivation to substitute conventional fossil fuels by renewable biofuels. More than just the interest of the market financial forces, government legislation is imposing a new order that obliges the use of biofuel. Many countries including the USA, the European Community, Japan and Brazil are committed to gradually substitute biofuels into their fleet of vehicles."

Jan 1, 2008

By Yuanbo Zhang, Zhaokun Tang, Mingjun Rao, Guanghui Li

The ballability of hematite ore with addition of a certain amount of pulverized anthracite and the induration features of anthracite–containing hematite pellets were studied. The results indicate that adding a certain proportion of anthracite can improve the quality of green pellets as well as the roasting performance of roasted pellets. The suitable mass dosage of anthracite is 1.0%–1.5%. Under the conditions of roasting temperature 1280 oC–1350 oC and roasting time 15 min–20 min, the compressive strength of roasted pellets is found to be more than 2500 N/P. Compared with hematite pellets in the absence of anthracite, the proper induration temperature is diminished by 20 oC, whereas optimal induration temperature range expands by 50 oC, and induration time is shortened by 5 min–10 min. Adding anthracite is an effective measure to improve the pelletization of hematite.

Jan 1, 2015

By James H. Owen

Because of price structure, ANFO is normally considered to be the most cost effective explosive used in quarry blasting. Results indicate that bulk smulsion can be more cost effective in applications where hole sizes range up to 6.5 inches in diameter while providing the simplicity of single product loading and storage. This can be accomplished without any fragmentation and/or movement loss usually in patterns which are about twice the size of ANFO patterns, allowing the combined drilling and blasting cost to be less when using bulk emulsions. Examples are presented supporting this concept using actual field results along with some simple calculations which take into account differences in the products such as density, matrix and detonation velocity.

Jan 1, 1998

By Austin E. Dwight

IT has been shown by Oelsen and Wever' that the effect of a solute element on the allotropic transformation in iron is dependent upon the quantity

Jan 1, 1957

By Bas R. Hemmen

GeoBrain is a facility at GeoDelft with the purpose to provide society with all relevant geo-engineering knowledge and experience in a structured way. On the basis of the available knowledge and experience engineers, decision makers and construction supervisors can come to a fast, reproducible and objective choice, taking into account the consequences. The paper presents examples from the GeoBrain experience databases and forecasting models developed for foundation engineering and directional drilling, or: "GeoBrain Foundations" and "GeoBrain Drilling". GeoBrain is closing the gap between theory and practice. It is aimed directly at reducing uncertainty and the costs of failure, thereby increasing the quality of profession and minimising the risk in geo-engineering works.

Jan 1, 2006

WMC was a late entrant into Indonesia in mid-1996, but had considerable experience and success in exploring in Asia, particularly the Philippines since 1988. Given the geological similarities to the Philippines and IndonesiaÆs superior æcradle to graveÆ Contract of Work (CoW) tenure system, the entry into Indonesia was a logical decision but nonetheless a result of detailed planning. At the time of WMCÆs entry, Busang in Kalimantan was still a 60 moz wonder and the euphoria of this apparent discovery had overflowed into every aspect of exploration. Many junior mining companies and tenement speculators were clamouring for properties in Kalimantan, whilst other serious and capable explorers had to compete for properties and exploration personnel in an era of high and often unrealistic expectations. The picture in late-1998 and through 1999 is dramatically different, as the worldwide downturn in the price of most metals coincides with financial and social crises throughout most Asian countries. The impact of this has been particularly severe in Indonesia and when coupled with the negative sentiment of the Busang fraud has resulted in an exodus of junior companies and also some of the majors. This is understandable given the much publicised social unrest, uncertainty of government, mooted changes to the eighth generation CoW, increasing illegal mining and heightened community expectations. The reality however is somewhat different and although clearly a crisis in many respects, it is also a time of great opportunity.

Jan 1, 1999

By D. Fray

Electrochemical processing using molten electrolytes is undergoing a considerable renaissance due to several innovative ideas being explored both in the laboratory and also at the pilot scale. Several of these new ideas are related to developments in energy generation and storage and involve solid electrolytes. Sodium has been prepared by the electrolysis of sodium carbonate or sodium hydroxide with the transfer of sodium ions through a sodium beta" alumina membrane and magnesium oxide dissociated by the removal of the oxygen through a stabilized zirconiaelectrolyte incorporating a fuel cell electrode. By using halides with highly electropositive cations, such as molten calcium chloride, it has been found that the favoured cathodic reaction, when oxygen is present, is the ionization of oxygen and not the deposition of calcium. This approach has been applied to the reduction of many metal oxides including titanium, zirconium, niobium and rare earth oxides and, by using a mixture of oxides as the cathode, homogeneous alloys are produced. This concept can also be applied to deoxidation of solid and liquid metals. Refining of metals is possible using intercalation compounds and, in a completely different application, it has-been found that, by intercalating alkali metals by electrolysis of alkali halides into graphite, it is possible to produce carbon nanotubes and nanoparticles. The technological opportunities of these various concepts will be discussed.

Jan 1, 2004

By William H. Hansmire

The Modified Detroit River Outfall No. 2 (MOD DRO-2) will discharge treated wastewater to the Detroit River. Construction of a 6.4-m-diameter, 1.9-km-long tunnel was halted in 2003 by flooding during tunneling with an open face hard rock TBM. A new design for a higher rock tunnel, a ?Modified? design, was completed in 2007 and Notice to Proceed to the tunnel contractor was given in November 2008. Project duration is four years for completion of tunneling and start of outfall tunnel operation. This tunneling project has high groundwater pressure (5 bar), pervious limestone rock of up to 140 MPa (20,000 psi) strength, and hydrogen sulphide in the groundwater. The new tunnel will be connecting to access shafts and outfall diffuser riser shafts previously built for the now-abandoned tunnel. The new tunnel design construction contract, and initial planning to use a pressurized-face (slurry) hard rock TBM are presented.

By Ray Brainard

Charleston Water System?s Daniel Island Extension Tunnel, initially thought to be the simplest of the four replacement tunnels to design and build, became the most challenging after the discovery of an unexpected 30-ft thick lens of sand in the normally consistent Cooper Marl while sinking a shaft on Daniel Island. This paper will explore the challenges involved with determining the extent of the unforeseen lens of sand, the accelerated boring program, and the redesign of the vertical alignment?keeping the alignment between the sand layer and the bottom of the Cooper River. It will describe how the challenges were overcome, and how the Owner, Engineer, and Contractor were able to team together to achieve the desired results.

By A. G. Rozner

TRANSVERSE rupture tests have been commonly used in mechanical investigations of brittle materials. The specimens are simple, easy to prepare, and loading presents no difficulty. Owing to the complexity of stress distribution in bending1 one can determine stresses rigorously only for the elastic range. The bend-test results, however, are at times converted into tensile-strength data, determined as maximum fiber stress. The assumption is made that for small plastic deformations the linear stress-strain relation applies. This problem was experimentally investigated by Bach3 who tested cast iron in bending and in tension and found that the maximum fiber strength obtained in bending exceeded the experimental tensile strength by a factor depending on the geometry of the tested piece. The factor varied from 1.57 for a rectangular cross section to 2.12 for a circular cross section of the tested beam. Since this work was carried out 60 years ago, the cast iron used could be expected to have been highly brittle, thus the extent of plastic deformation prior to fracture very small. We have therefore carried out a number of tests on magnesium-modified cast iron with an average elongation of -5 pct. It was hoped that the data obtained from the tests would serve as a guideline for comparing data obtained in tension and bending for brittle materials. Mechanical properties were measured at room temperature on an Instron tensile machine at a crosshead speed of 0.05 in. per min. The three-point bend test employed cylindrical bars 0.20 in. in diameter with a 1.0-in. span. For the tensile test, cylindrical tensile specimens with a gage length of 0.85 in. and a diameter of 0.160 in. were used. Results are summarized in Table I. From Table I one can see that fracture strength

Jan 1, 1965

By W. Lee Daniels

Significant deposits (> 4,000 ha) of heavy mineral sands were discovered in the USA Coastal Plain of Virginia and North Carolina in 1989. The majority of these lands support highly productive row crop agriculture, and the development of restoration protocols that would return these lands to agricultural use was deemed to be critical to the long term sustainability of mining operations. Virginia Tech worked closely with all stakeholders to develop appropriate restoration protocols and to coordinate their implementation. Full-scale mining operations at the Old Hickory Project in Virginia were initiated in 1997 by Iluka Resources Inc., and restoration protocols have continued to evolve in response to a variety of economic, technical, and social issues. Approximately 750 ha of land are in various phases of backfilling and final reclamation. Return of these lands to agricultural row-crop production has been complicated by lateral variability in mine soil physical conditions, excessive compaction, and limited topsoil return. However, within the past two years, a series of tailings deposition and soil reconstruction practices have been developed and implemented that significantly improve post-mining soil productivity. Deep ripping and appropriate use of organic soil amendments have been particularly effective at restoring post-mining soil productivity.

Jan 1, 2005

By Xie Qiang

It is known that the stress state inside rock discs under Brazilian tests is neither simple compression nor tension, but a complex combination of both stress types, as well as for a beam subjected to bending, where compressive and tensile stresses are separated by the neutral axis. In this study, AE generation was obtained on pure white marbles from south Portugal that were submitted to both Brazilian and bending tests. Main questions to be answered were: (1) Does Kaiser effect exist in tests which create complex distributions of tension and compression? (2) Are there any meaningful differences in AE behavior of marble under Brazilian and bending tests?

May 1, 2009

By D. R. Babich, E. R. Bauer

Noise-induced hearing loss (NIHL) in mine workers, especially underground coal miners, continues to be a problem in the mining industry. The recently enacted MSHA noise standard, Part 62 – Occupational Noise Exposure (Federal Register, 1999), is aimed at reducing NIHL in the mining industry. The U.S. National Institute for Occupational Safety and Health (NIOSH) is conducting a cross-sectional survey of noise sources and worker noise exposures to address NIHL in various aspects of coal mining including surface mining, coal preparation plants and underground mining. In underground bituminous coal mining, noise surveys, consisting of full-shift worker noise exposure, time-motion studies and equipment noise profiling, have been completed on longwall and continuous miner sections in six underground coal mines. The studies revealed widely varying shift-to-shift worker exposures, with workers in certain occupations routinely exposed to potentially hazardous levels of noise. A summary of these studies is reported, including worker dose, source/dose relationships and equipment noise profiles.

By Y. H. Wang

During the last two decades many research projects were conducted to study the load requirements for the powered supported longwall faces (1-6). Significant results had been achieved by these researches. Most of the previous studies were rarely designed to understand the mechanisms of interaction between the supports and the surrounding rock, or to correlate the stress conditions around longwall faces to the mining operations both in time and space. In case of the shield supported faces, the roof-to-floor convergence is very difficult to measure due to the high percentage of roof coverage. The external load on the supports can not be determined from the leg pressure data alone due to the existence of the lemniscate links. Therefore, there is a real need in that a simple engineering method be developed to monitor the variations of roof load on the shield supports, the roof-to-floor convergence and the roof stress restoration in the gob area as the mining proceeds. Only with the results of these measurements, a further understanding about the mechanisms of interaction between the supports and the surrounding rock can be achieved and a criterion of designing or selecting the optimum mechanical parameters of the shield supports can finally be developed.

Jan 1, 1986