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By T. J. Morris

"From November 2014 through September 2016, Westmoreland’s Coal Valley Mine utilized a Marion 7450 electric walking dragline to extract 1.2 million tonnes of a vertically-dipping, 52-meter wide, fault-thickened seam, beneath a conventionally-excavated pit bottom. Mine planning and operational hurdles encountered throughout a kilometer of mined strike length included mitigating highwall instability in both hanging and footwall slopes, water management, and end-of-life machine reliability and maintenance. The most substantial challenge has been the depressed global coal market. However, the successful application of this mining method significantly aided the overall cost of production at the site. The valuable experience gained from this project will be extended to future mining areas where this technique can be similarly applied. INTRODUCTION Coal Valley Mine is located approximately 220 kilometers southwest of Edmonton, Alberta, Canada, in the foothills of the Rocky Mountains. Since commercial production began in 1978, more than 84 million clean tonnes of coal has been produced and sold domestically as well as exported overseas for power generation. While the existing processing plant has a nameplate capacity of 4 million tonnes per year, the site has operated at a 2 million tonne rate since 2015 due to depressed export markets. Westmoreland acquired the mine as part of its purchase of Sherritt Coal Operations in April 2014. The mine operates 24 hours a day, 7 days a week, with an IUOE workforce of 261. GEOLOGICAL SETTING The geology of the Yellowhead Tower mining area differs significantly from previous mining areas at Coal Valley. The Mynheer coal seam discussed herein consists of steeply dipping, highly-sheared, thrust-faulted, and heterogeneous coal pods. Deep set, southwest striking thrust faults were the likely mechanism for the podding and have resulted in overturned, rolled and highly sheared seams with zone thicknesses of up to 65 meters.The hanging wall is characterized by soft bentonitic mudstones and siltstones, overlain by massive competent sandstone. The footwall is defined by a hard volcanic tuff, interbedded with thin, sporadic coal seams. The sandstone above and volcanic tuff below constrained the faulting system within this zone, enabling the mass podding that has afforded the opportunity for large-scale mining."

Jan 1, 2017

By Walter E. Heinrichs

This case history really started during the tail end of WWII when two Navy men, both Colorado School of Mines graduates, got together in Washington, DC, while they were assigned to the Office of Navy Petroleum Reserves doing some of the first aerial magnetometer work ever done on a practical oil exploration basis over the offshore area of the Gulf Coast. When separated from Naval Service active duty in 1946, the two men, Walter E. Heinrichs, Jr., and Robert E. Thurmond, tried, unsuccessfully, to form a commercial air magnetometer business. Later they got together again in Jerome, AZ, with Newmont Mining's early geophysical exploration endeavors from 1947 to 1949. Subsequent to the Newmont experience, they jointly proposed a specific mining geophysical exploration and development program to Herbert Hoover, Jr., then president of United Geophysical Co. of Pasadena, CA. Mr. Hoover, in consultation with his father Herbert Hoover and others of his staff at United, particularly Edwin G. Schempf, executive vice president, and Raymond A. Peterson, vice president of research, agreed to establish the proposed program under United's auspices, to be headquartered at Tucson, AZ. The primary objective would be to practically test and develop various mining geophysical methods and techniques while exploring particularly for base metals in the general area of southeast Arizona and southwest New Mexico.

Jan 1, 1991

By Donald W. Gentry

It appears that the competition for increasingly scarce international mining investment capital will continue among developing countries. Indeed, there is growing evidence this competition may be on the verge of becoming destructive and cutthroat in nature. While this may be viewed as good news by short-term, speculative investors, it could have dangerous repercussions for international minerals producers over the long-term. It seems there has been a continuous parade of traveling foreign delegations touting the virtues of mineral investment in one country or another. These pitches all contain the politically correct key words, such as macro-economic reform, political reform, privatization, liberalization of laws governing mining and related investment incentives, reconciliation of ownership and right-to mine issues, and tax reform specially tailored for the minerals sector. Unfortunately, some of the information being trumpeted is based on plans, concepts or hopes for change rather than actual reforms approved by all necessary governmental entities. In yet other situations, the information provided consists of half-truths at best. Too often, potential minerals investors, faced with metals and minerals prices hovering near their recession lows and the need to offset old, high-cost operations, desperately want to believe all they hear about investment alternatives cast in a near-utopian setting. However, the virtues being proffered for mining investment abroad do not eliminate the need for careful scrutiny of subtle variations of traditional risks associated with foreign investment that can drastically affect the economic viability of mining projects.

Jan 1, 1993

The minerals industry contributes to the economic growth, prosperity and quality of life of nations, particularly in areas where there might be limited opportunities for employment in other sectors. However, notwithstanding their economic importance, the minerals extraction and processing industries are considered to have significant impacts on the surrounding environment. In recent years many mines have implemented modern monitoring technology and modelling of the monitored environmental parameters to provide scientifically proven indicators about the state of the environment. The flexibility required by the minerals industry to respond dynamically to a changing natural, social and economic environment has become a major consideration. Whilst the notion of continuous improvement is embodied within most environmental management systems, what is now required is a structured audit trail which tracks the flow of resources through the production process to the ultimate environmental impact associated with their consumption, transformation and disposal. Imperial College is coordinating an EC funded project, which is developing a methodology to minimise the ?full life-cycle? impact of metalliferous mining projects, adopting an integrated approach to production and process design, and the costs involved. In order to develop a life cycle assessment (LCA) system that will incorporate different types of data related to the minerals extraction operations, a data inventory was designed and coded in an object-relational database model. The calculation procedures accounting for the input/output balance of the alternative scenarios for mining production, processing, waste disposal, monitoring, and their financial implications are being programmed into a software system. This paper presents the rational and innovative aspects of this work. The methodology developed for the life cycle database is illustrated for the mining production and gaseous emissions components of the system.

Jan 1, 2003

By Ch. Apostolaki

Eighty samples from Roman wall paintings from ancient Corinth were studied by means of optical and scanning electron microscopy coupled to an energy dispersive analyzer, X-ray diffraction and image analysis techniques. The goals of the study were the identification of the exact nature of the pigments and the technical features of paint application (binding medium, adherence to plaster, thickness of the pigment layer), which would provide evidence about the painting technique (fresco or secco). The main plaster is calcitic with secondary calcite as a cement binder to the primary calcite grains. All pigments, except Egyptian Blue, were naturally occurring ochres or pigment minerals, such as limonite, goethite, hematite for yellow, brown and red hues, cinnabar for red hues and celadonite for green color. The presence of specific elements such as Ni and Cr or minerals such as olivine, in the yellow, brown and red pigments, gave an indication about the provenance of the original pigments, which seems to be from Cyprus. The black color was represented using charcoal. It seems, finally, that for the pigment application the fresco technique was used, while secco is also apparent.

Jan 1, 2006

At first glance the staid Joralemon background does not seem to equate with the life of adventure that irresistibly called me for over 70 years. But my ancestors had their adventures too. My father's family were Dutch Reformed Protestants who had energy or daring enough to come to America to escape the Catholic persecution that followed the Massacre of St. Bartholemew. The first Joralemon came from Friesland to New Amsterdam m 1636, just after Peter Stuyvesant. My father's mother's family, the Berdans, were French Huguenots who came to northern New Jersey only a little later to escape the Catholic domination in France. Some say that the first Berdan to come to America was given all the land between the Passaic and the Hacken-sack Rivers by King James. Whatever, the Berdan family settled there and was able to make a scanty living by farming and selling their produce in Manhattan. The spirit of adventure in my mother's family was just as tenuous. Gamaliel Beaman was pastor of a shipload of Puritans who came to Massachusetts in 1636. Gamaliel's descendents were peaceful farmers and some ministers in New England and later New York State. They had got all of the adventure out of their systems in the long and dangerous voyage across the Atlantic to escape religious persecution. The Joralemons and the Berdans married into families that had been in America almost as long as they had. On my father's side the Berdans, Doremus, DeGreys, Vanderbeeks, and Varicks showed by their names their Dutch or French Huguenot stock. The only one who achieved any fame was Peter Varick, who was George Washington's military secretary during the American Revolution. After this he was nine times mayor of New York and was one of the founders of Kings College, later Columbia University. He was responsible for one of my few ancestral claims to distinction. When the Marquis de Lafayette made a fare-

Jan 1, 1976

By M. T. Errington, P. C. Miller, W. E. Hardwick

Paper discusses in general terms the techno economic merits of various types of aerated biological reaction systems. The current status of the technology leaves many questions unanswered and hence the choice of the best system to employ is open to discussion. Reasons are given for the choice of the reactor system to be built and operated by Davy McKee. The pilot plant has been designed to provide answers to a number of the questions posed by this technology.

Jan 1, 1998

By P. F. Hara, O&apos

Stratabound Proterozoic precious metal mineralization in central Arizona is associated with felsic and adnesitic to mafic volcanic rocks and sediments derived from these rocks. Hydrothermal fluids associated with felsic volcanism form gold mineralization within hotspring vent complexes or within asymetric basins, which flank the vent complexes and are filled with tuffaceous sediments. Massive to semi-massive sulfide copper-zinc systems associated with felsic volcanism may locally contain small gold occurances either laterally or vertically zoned from the ore. In andesitio to mafic rocks, zinc-lead-gold-silver-copper bearing mineralization and gold mineralization are both associated with feruginous sulfide bearing cherts. The partitioning of gold into these specific geologic environments may be related to variations in temperature and composition of the hydrothermal fluid and the depth of the seawater-sediment interface below sea level during the mineralization event.

Jan 1, 1988

By M. G. Skowroski, G. G. Eichholz, J. P. Ambrose

Introduction It has long been known that there are extensive deposits of phosphate-bearing deposits in the Coastal Plain of Georgia in many locations that are similar to those being mined commercially in central Florida. A major drilling program was conducted in 1966-67 by the Georgia Geological Survey (GGS). The economic potential of some of the material uncovered was evaluated at that time by a team at Georgia Institute of Technology led by Dr. J.E. Husted. There were some promising results. Since then, there has been little commercial interest in pursuing this matter, though the potential for development remains. In the long term, Georgia's phosphorite deposits could be a major source of income to the state if they were commercially processed. Phosphorite deposits contain significant levels of uranium and thorium. Uranium concentrations in Florida phosphate aggregates have been found to be 120 to 140 ppm. The presence of high concentrations of uranium means that there is a small but finite concentration of radium, which subsequently leads to radon gas emanation. It is the radon emanation and its progeny that may pose the largest health problem in many types of mining. Surface mining operations can possibly elevate the radon and radon daughter concentration in the vicinity. There is always some public concern whether any increase in the radon concentration in the atmosphere by mining (surface mining in the phosphorite case) could elevate the risk of cancer in the nearby population. At the present time, a great deal of attention has been devoted to the possible health effects of radon and its decay products in the inhaled air in mines and inside buildings built on mill tailings or uranium-bearing rock (Gesell and Lowder, 1980). Several evaluations have been published on the potential health effects of the Florida phosphate operations (Guimond and Windham, 1975; Roessler et al., 1980; Travis et al., 1979) and for buildings incorporating phosphate slag aggregates (Kahn, Eichholz, and Clarke, 1983; Roessler, Roessler, and Bolch, 1983). They all indicate that such potential effects are small, but tangible, compared with other radiation effects, for instance in the nuclear industry (Cohen, 1981). In view of the current concern, especially by the US Environmental Protection Agency (EPA), with the radiological consequences of large-scale mining of uranium-bearing phosphate rock (Guimond and Windham, 1975), it was decided to assess the potential radiological consequences if the Georgia deposits were developed. This paper presents an attempt to estimate the magnitude of any radon-based health effects that might arise from future mining operations in selected areas of the Georgia coastal region. To do this, a calculational model was developed that took into account the mining operations themselves, the atmospheric dispersion of the radon released, and the radon daughter concentrations in nearby towns. The model was applied to both extremes. The first application was a hypothetical mining operation in Echols County. Echols County is very sparsely populated and, unless living very close to the site, a person would probably experience little radiation exposure, if any. The model tries to prove this point. The second application was at a site near Savannah, Georgia. Both sites contain economically feasible phosphorite deposits and were not entirely hypothetical in that sense. Site selection In the course of the South Georgia Minerals Program (Furcron, 1967), an extensive series of drill core samples had been collected from various mineral occurrences in the coastal plain. It was found that the cores from the previous drilling program (Furcron, 1967), though carefully preserved, were not readily accessible. But the GGS reports did contain gamma logs of all the holes surveyed. With the cooperation of Dr. Neal Shapiro of the Survey, some core samples were selected and assayed, and used to calibrate the gamma log data. Samples from locations known to have detectable radioactivity were screened and counted. Their measured uranium content was used to calibrate the gamma log profiles for those same holes as obtained by the GGS. On this basis, two of the higher-level sites were selected and the calibration was used to obtain integrated uranium concentrations over the length of the borehole. It is customary to describe radon and radon-daughter concentrations in "working levels" (WL), where one WL represents a concentration of radon daughters capable of releasing 130 000 MeV of alpha particles, equivalent to 100 pCi of radon in equilibrium with its daughters per liter of air. A representative concentration is 0.15 WL, below which radon levels are widely considered to be negligible. For the mine sites selected, the surface area and rock volume were determined to estimate their radon content. Working-level values were then estimated for the assumed radon release from the crushed ore and the exposed surfaces of the mine pit. According to Kisielewski (1980), 93.4% of all radon released from open-pit operations is released from the ore zone; thus, the calculations assumed that those surface areas were the main sources.

Jan 1, 1987

By G. R. Brunskill

The molybdenite flotation plant at the Magma Copper Co. San Manuel concentrator has been in operation since 1956. In January of 1980, the plant was converted from a hydrogen peroxide-ferrocyanide process to the current sodium cyanide-sodium hydro- sulfide process. This paper is an operational review of Magma Copper Co.'s molybdenite recovery circuit, column cell flotation experience, and use of on-stream X-ray fluorescence analysis.

Jan 1, 1987

By T. Moller

There are differences in design aspects between steel and rubber linings in grinding mills. This paper describes the basic design rules for rubber liners for different grinding applications. When converting a mill from steel to rubber liners, the design must be changed from such familiar steel liner shapes as wedge bars and plates, wave liners, ship-lap, etc. to take advantage of the characteristics of rubber. Very little of the knowledge of the wear properties of steel can be used for the design of rubber mill liners.

Jan 1, 1989

By S. E. Restrepo

In recent years, mining operations have experienced the impacts of climate variability, increasing costs, and changes in the socioenvironmental dynamics of the territories. For this reason, the aggregates industry needs to design and define concrete and immediate actions to address climate change. An appropriate way to achieve this is as follows: • Calculate greenhouse gas emissions, sources, and relevance factor. • Make projections of future scenarios. • Design and implement action plans The proposed climate change mitigation and adaptation projects are logistical optimizations of mining equipment (mitigation). Second is the design of an early warning system to predict possible flooding (adaptation).

Mar 2, 2022

By B. M. Ghadiali, J. B. Putnam, T. P. Smirnoff, M. A. Elioff, P. F. Ryan

Geotechnical investigations for the Mid-City Extension of the Los Angeles Metro revealed high concentrations of toxic hydrogen sulfide (H2S) gas as well as methane. Testing techniques employed to determine the extent of gasses, and to identify potential treatment measures, included gas sampling with cone penetrometers and soil-gas extraction with air injection testing. A gas reservoir model was developed to predict inflows into excavations. Other studies included a hazard evaluation and a general data search for other H2S occurrences and geologic conditions that could facilitate the accumulation of H2S. The paper describes the investigations and proposed design and construction alternatives.

Jan 1, 1995

By Carlo Grandori

Foreword In loose ground and soft rock formations, mechanical tunnel boring is necessarily dependent on the adoption of shield machines and the application of adequate support or lining structures. These structures are erected either within or immediately behind the rear portion of the shield and provide the required reaction to the forward thrust. In competent rock formations where systematic support is not a requirement, hard rock tunnel boring machines generally advance by thrusting from a structure gripped against the tunnel walls. These machines may feature a more or less extended cutterhead shield or roof support, but when in weathered, fractured or otherwise weakened ground, or in fault zones filled with soft gouge, the gripper mechanism often cannot provide enough thrust reaction to advance the cutterhead. Under these conditions, early support of the arch and walls is generally required in the form of rock bolts, steel rings and laggings and some times of a primary concrete lining placed in the short section between cutterhead and grippers. Such tunnel support measures generally fail to produce an adequate increase in thrust reaction capacity, but

Jan 1, 1976

By Steve Kral

"Repairing and replacing the nation’s aging and crumbling infrastructure has become a major issue with the American public. It is no secret that the upkeep of roads, tunnels, bridges, and water and waste water facilities has been neglected for decades. Cities, states and towns across the United States are now grappling with these issues, ones that will take decades and billions of dollars to fix.Because of this infrastructure issue, the North American tunneling industry is flourishing. Cities across the country are looking to go underground to alleviate traffic issues, transporting water and waste water to more people in more efficient ways.In October, the seventh annual Cutting Edge conference was held in Atlanta, GA. Put on by the Underground Construction Association of SME and Britain’s Tunnelling Journal, about 175 tunneling and underground construction professionals from around the world attended. Attendees included owners, designers and contractors. An accompanying exhibit included 28 companies.The theme of the two-day conference was Advances in Tunneling Technology. Speakers examined the latest advances in tunneling technology, its methodology and how these advances can be harnessed to assist upcoming major tunneling projects. The conference featured a tailored, high-end, single-track program of subject-specific presentations that focused on innovation and practical experience. Two in-depth panel discussions at the end of each day were also included.Patricia Mulroy was a keynote speaker on Monday. She is senior fellow for climate adaptation and environmental policy at The Brookings Institution. Like many others, Mulroy believes the U.S. infrastructure in in a state of disrepair. But, she said, no one wants to talk about it. “We need to have a conversation about infrastructure. We cannot be afraid to talk about building it and the cost.” For this to happen, though, the nation needs leadership."

Dec 1, 2018

Traditional finance theory recommends discounted cash flow (DCF) analysis as the tool to value mineral properties. Yet, the calculated values by this method are usually lower than the market value. Finance theory also advises us to develop an undeveloped project immediately if its net present value is positive. Most projects are, however, only developed when the economics are highly favorable. This paper uses insights from option-pricing theory to explain these divergences between market behavior and finance theory and presents simple modifications to discounted cash flow analyses that will lead them to produce correct valuation and development timing advice.

Jan 1, 1999

By Duk-Won Park

Since geologic anomalies are one of the governing factors of instability of underground openings, it is extremely important to know in advance the locations and extent of these anomalies such as faults and weak zones. At an underground coal mine in the Black Warrior Basin, core drilling was conducted to find a fault in an area where they were planning to locate longwall panels and possibly a shaft. Core logging did not provide sufficient information to delineate the exact location, strike, and dip of the fault. However, a high resolution reflection seismic study successfully solved this problem. This experience proved the seismic exploration technique could be used for premining coal exploration by reducing drilling costs and providing more accurate and detailed information about geologic anomalies.

Jan 1, 1988

By James F. ` King

This paper reviews the changes which have taken place in the supply of smelter-grade alumina and refinery-grade bauxite over the past twenty years. It highlights the current situation and identifies some trends which are to be expected in the medium- and longer-term future.

Jan 1, 1986

By D. C. Panigrahi

The paper presents the application of Object Oriented Programming approach for the development of a network simulation model based on nodal pressure method using linearised flow equations. The convergence and computational efficiency of the algorithm have been investigated. Finally the paper re- ports the validation of this algorithm in actual field conditions.

Jan 1, 1996

By Andy J. Robinson, Mark D. Claassen

Railroad companies and transit authorities have been slow to acknowledge that for many—utility crossings, a direct pipe installation below live rail can be just as effective as a more intrusive traditional cased crossing. Properly designed and specified pipe jacking work, and specifically pressure-balanced microtunneling, coupled with careful specification and analysis of geotechnical monitoring and, where necessary, ground improvement measures, can produce a low-risk, low ground movement solution to the needs of utility companies and municipalities whose services need to pass below urban and rural rail corridors. This paper discusses the design, geotechnical and ground improvement aspects of microtunnel crossings below active heavy and light rail lines and crossings beneath active subway tunnels.

Jan 1, 2003