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By Julio C. Martinez, Jeffrey L. Rice, Hayden Weschler

This paper details the extensive underpinning required to hold up the 39th street Bridge while demolishing its massive support piers and building a 30ft deep Cut/ Cover RR tunnel beneath it. The underpinning/SOE support required the construction of 16 large hand dug pits 36ft deep that were reinforced and concrete filled. In addition, an extensive steel support system was tied into the bridge super structure. All of the underpinning/tunnel construction was done while a 110ton crane sat directly atop the heavily trafficked – 66 ft. wide bridge. The tunnel excavation, concrete lining and final bridge pier support work will also be presented. All work was done within 5ft of active mainline tracks and that required tight grouting behind all lagging to eliminate any track settlement.

Jun 13, 2021

By F. Calizaya

This paper explains and discusses a computer program developed to determine the ventilation design parameters for complex auxiliary ventilation systems such as those found in the construction of long excavations with multiple headings. The program is based on the principle of partitioning the system into segments of finite length, and formulating and solving the resulting networks recursively. The application of the program is illustrated by the detailed solution of an auxiliary ventilation system proposed for the Exploratory Studies Facility (ESF) at the Yucca Mountain project, Nevada.

Jan 1, 1994

By B. Goertz

Since the turn of the century the mining industry in the United States has had a number of serious mine explosions, fires and ground fall disasters that have led to a major re-evaluation of mine communication and rescue practices. One of the hindrances of current underground communication technologies is the potential of lost or cut connections when a serious accident, such as an explosion, fire, inundation or major ground fall, takes place. The Mine Improvement and New Emergency Response Act of 2006 (MINER Act)1 mandated that each underground coal mine in the U.S. must provide for two-way wireless, post-accident communications between underground and surface personnel as well as electronic tracking of underground workers One area that has gained renewed attention in the mining sector is Through-The-Earth (TTE) communication. TTE technology has a major advantage in that transceiver devices can be carried by miners and set up quickly during an emergency, since they require no wire connection to the surface. TTE technology uses ultra-low frequency (1 to 4 kHz) electromagnetic waves, requiring relatively large wire loop antennas and highly sensitive receivers. The signal bandwidth is narrow and the permissible antenna currents in coal mines are restricted, which has led to limited usability of TTE technology in the past, as evidenced in research studies conducted by the U.S. Bureau of Mines in the 1970s. Yenchek (2012)2 pointed out that recent advances in receiver and signal processing technology have enabled voice and text communication capabilities and much improved sensitivity that offers new possibilities for TTE communication in mining applications. One company that has been developing such technology is Vital Alert Communication Inc. Vital Alert has been providing TTE communications since 2003 with a growing focus on emergency response and portable systems. The company?s Canary® Go System is one such product that looks to provide reliable communication capabilities in a portable, user friendly unit that can be utilized both for normal operation and mine rescue scenarios. Researchers at the Colorado School of Mines (CSM) have tested the Canary Go TTE communications system in the CSM Edgar Experimental Mine to determine signal propagation distances, signal quality and aspects of practical application.

Feb 23, 2014

By Drupad B. Desai, Bruce Chang, Jay L. Merritt

This paper reviews difficult ground conditions encountered along the alignment of large-diameter sewage tunnels for the City of Los Angeles. It offers a detailed one-of-a-kind solution to a unique problem for shallow urban underground tunnels in a seismic zone, using state-of-the-art materials, technology, and equipment. The following topics are discussed in detail: • Geotechnical Design consideration for tunnel traversing through an active fault zone. • Seismologist evaluation of possible fault-offset problems where a fault zone crosses the alignment, in the event of an earthquake of moment-magnitude 6.5. • Probability analysis regarding "recurrence interval." • Structural design of tunnel subjected to displacement, subjected to axial elongation or shortening, and capable of rotational freedom. • Special joint details.

Jan 1, 1989

By Gary J. Fletcher

Mining and processing activities which are proposed on private land, state leases, or unpatented mining claims are governed by numerous local, state, and federal laws which identify the procedures and conditions which must be met before resources can be developed. The respective government agencies responsible for the administration and enforcement of these laws have promulgated supporting regulations and guidelines, and have implemented certain permit and approval processes to ensure compliance. Each exploration project has a unique environ- mental setting and location which further dictates the types of air, water, hazardous waste, and wildlife laws and regulations which must be complied with before development commences. The environmental planning process should be the first step in the evaluation of existing company properties and the potential acquisition of other mineral properties. However. many company don't consider the environmental requirements for a project until the decision is made to develop the property for mining and processing. If a mining company wants to expedite the environmental planning process, it must first develop an in-house process for evaluating the project and determining the environmental approval procedures in the state where the project is located. The first stage of environmental planning involves general information which can set the overall company philosophy for development of projects.

Jan 1, 1987

By D. Conklin

Annual fish monitoring of the Red River, NM from the town of Red River to downstream of Questa, NM has been conducted since 1997. This long-term dataset, sponsored by the Chevron Mining Inc. Questa Mine provides an opportunity to evaluate the fish community response to natural phenomena, such as landslides and drought. Hydrothermal scars are present on drainages to the Red River, which can contribute large quantities of sediment to the Red River during localized storm events. Sediment inputs from the hydrothermal scars result in decreased habitat and water quality conditions within the Red River. Landslides from the hydrothermal scars contributed large amounts of sediment to the Red River in the summers of 2002 and 2007. Resident trout populations in the Red River after summer 2002 were depressed at sites adjacent to and downstream of the hydrothermal scars. Resident trout populations had begun to recover by 2005 and 2006; however, after the summer 2007 landslide, the resident trout population was again drastically reduced. In fall 2007, 13 resident trout were collected from 11 sites in the approximately 23 km reach of the river, compared to 691 from the same 11 sites in fall 2006. Resident trout density and biomass has gradually increased since fall 2007, and flows have removed sediment from the study reach. A combination of increased sedimentation and decreased water quality were likely responsible for the decreased resident trout populations in the Red River. Drought and the lack of flushing flows appeared to exacerbate the problem of high sedimentation levels from 2001 to 2004. Climate models predict prolonged periods of drought and increased intensity of storm events, potentially resulting in less favorable conditions for the resident trout population of the Red River in this area.

Jan 1, 2011

By Edward T. Koch

With the dramatic increase in world demand for basic raw materials, open pit mining is proceeding at an unprecedented rate. A viable demand is the ever tempting Siren's song for increased production or new facilities. When the Siren's lure is viewed against the panorama of today's world economic milieu the concomitant Scylla and Charybdis are seen in the form of high capital cost and high operating cost. If the economic realities of present day open pit mining are to show a proper return on investment, a clear and penetrating eye must be cast upon the area of mine planning. This paper deals with the problem of overburden removal. In almost every open pit mining operation overburden removal is a significant part of the capital cost and operating cost of the total operation. This paper deals with a new and unique method to affect economical overburden removal. Well known to all are the parameters surrounding draglines, shovels, and bucket wheel excavators. All of these machines require a reasonably stable soil to support them and the shovel and bucket wheel excavator require a reasonably stable bank in which to operate. Their reliability, portability and rate of production per dollar of invested capital are good.

Jan 1, 1975

By Robert Sturk, Knut O. Halvorsen

"INTRODUCTION AND BACKGROUND The world needs visionary people to break new ground and bring development forward. The human race has an inherent power and lust to explore and push borders, but also to connect and bring people together. Transport of people and goods has through history been a key factor to develop societies and increase collaboration between people and regions. Today, in the era of globalization, efficient transport systems are still vital for further development. Often, ideas of bold projects, like long bridges or tunnels, have been raised long before those projects are realized and actually built. This shows that visions must gradually be transformed into feasible business cases and sustainable political solutions. In some cases also technological development is necessary to make visions come true. Isambard Kingdom Brunel, indeed a visionary engineer, completed the oldest underwater tunnel in the world when the Thames Tunnel in London was opened in 1843. This tunnel is still in operation and now part of London’s rail transport system. Another milestone for the tunnelling industry was passed when the 54 km long Seikan tunnel in Japan was opened in 1988 after more than 15 years of construction. This tunnel is presently the world’s longest railway tunnel. Together with the 50.5 km long Channel tunnel between the UK and France, which has the longest undersea portion 37.9 km, they constitute examples of pioneering engineering projects that bring the industry forward. In 2016, the Gotthard Base Tunnel will be opened and then becomes the longest railway tunnel in the world with its 57.1 km. The trend is obvious that tunnels throughout the world are getting longer and longer. The Brenner Basis Tunnel presently under construction will yet again break the record being 64 km long. Presently, a number of even longer tunnels are planned and under design, some of these also have very long subsea portions, e.g. Bohai Straight Tunnel (123 km), Irish Sea Tunnel (around 100 km) and the Helsinki – Tallin fixed link (approximately 90 km). Northern Europe sees an increasing demand on efficient transport corridors to meet the growth of freight transportation between the Scandinavian Peninsula and central-Eastern Europe. Sustainable solutions will be required, and a shift from road/maritime transports to rail is imperative. Consequently, this paper describes yet another visionary project, a fixed railway link between Sweden and Germany, the Shortcut, to enhance traffic between these regions and to make it greener. It is true that this project still requires some work from politicians, economists and engineers to be realized, however, building a 100 km long tunnel under the Baltic Sea may become reality sooner than we think."

Jan 1, 2016

By H. Maleki

This paper recognizes the 100th year of research accomplishments by the mining industry resulting from close cooperation among mining companies, geotechnical consultants and researchers from the former United States Bureau of Mines in stability assessments and development of improved and productive mine designs. The paper provides an overview of dramatic developments in geotechnical instrumentation, and its applications in the U.S. and around the world for enhancing the understanding of ground response to mining-induced changes in stress, resulting in improvements in ground control technologies.

Jan 1, 2010

By A. J. Basu

Geotechnical design plays a key role in mine design. I A proper geotechnical design provides a safe working environment and facilitates efficient mining operation. There are mainly three design approaches I) judgmental, based on observational and experiential facts, 2) empirical, based on empirical design formulae, and 3) analytical, incorporating numerical analysis. Most design applications are based on the design methods one and two as mentioned earlier. However, complexities arise in deep underground mining operations and deep open pit mines. These complexities and difficult geological environment introduce more uncertainties and simple empirical formulae would not be adequate as a design tool. These situations require numerical modelling and analysis of the design problems including interpretation of the results obtained from the analysis. There are several tools available for performing the numerical modelling and analysis. A brief review of the available tools was addressed earlier (Basu and Kuruppu, 1995). The authors selected ANSYS (a general purpose finite element analysis tool) for use in mining geomechanics and geotechnical design. This paper includes several examples demonstrating the applicability of this software in designing structures applicable to mining geomechnics. The authors hope that the design examples will demonstrate the use of the numerical modelling and analysis application in excavation design.

Jan 1, 1996

By R. L. Grayson

In 2010, MSHA began holding hearings on a new coal mine respirable dust rule, which proposes a 1.0 mg/m3 standard, a separate 0.1 mg/m3 quartz standard, and the use of single-shift samples for compliance. Small mines largely comprise the ?hot spots? where dust diseases of the lungs increased dramatically over the past decade. This paper presents findings on the feasibility of small mines? compliance with the proposed new 1.0 mg/m3 standard. It gives probabilities of noncompliance by MSHA district, seam height, and selected ?hot spot? counties. Because silicosis and respirable quartz dust appear to be the primary issues related to a recent doubling of the prevalence of dust diseases of the lungs, multiple regression models for prediction of the average total quartz content of compliance samples are given. These findings have significant implications on the need for better dust control methods.

Jan 1, 2012

By Steve Kral

Competition from foreign coal producers could displace as much as 9 Mt/a (10 million stpy) of US coal bound for power plants located near waterways. But, according to a Maryland-based coal consultant, it could be worse. Theoretically, about 52 Mt (57 million st) of domestic coal could be vulnerable to imports by 1990, said Forrest Hill, of Hill & Associates of Annapolis. Hill was speaking to about 150 coal industry executives and experts at the third annual Coal Marketing Strategies Conference in November. Most were at the Denver, CO conference to pick up tips on how to sell coal in an oversupplied market. Imports threaten domestic markets Of the 200 utilities studied by Hill and his staff, 119 are situated near major waterways, he said. However, most of those waterways are not equipped to handle coal from the shipping lanes. Good news for US coal producers. But don't breathe too easily. Foreign coal still poses a major threat to domestic markets, Hill continued. The strength of the US dollar is an obvious factor. But easy access to US utilities located on waterways combined with low rates for ocean vessels give foreign producers another edge. And foreign mines are typically low cost producers. For example, Hill said Colombia's huge Cerrejon mine can deliver coal to an Illinois power plant for $47.87/t ($43.39 per st). That compares to $52.85/t ($47.95 per st) from a Kentucky coal mine. Also, Colombian coal producers can generate a cash flow even if the coal sells for $27.50/t ($25 per st). The main competition US producers face from abroad, as Hill sees it, comes from Australia, Canada, Colombia, Poland, South Africa, and, perhaps, from Venezuela. Domestic producers, however, do have some things going for them. Most US coal buyers, Hill said, "are not wild about the idea of buying foreign coal." A 10% price advantage or pressure from public utility commissions would be needed to force some of them to buy foreign coal, he said. Some of the utilities contacted said they would not commit to more than one-third of their stockpiles to a foreign source. Another advantage for US producers is that they have room in their long-term contracts to cut prices and still maintain a profit, Hill said. Railroads, too, have high profit margins written into their rate structures. They are also aware of the import threat. Therefore, they may reduce their rates accordingly to keep their markets. Marketing's role The energy price shocks of 1972 and 1976 caused major adjustments in world economics. Coal was no exception. High oil prices caused many utilities to look at less expensive coal. As the market improved, coal prices began to respond, said R. Gale Daniel, of Anaconda Minerals Co. But clean air legislation and the strengthening dollar caused havoc in the coal markets, he said. The price of oil crashed, taking with it predictions of record coal use. The result is an oversupply of coal that has led to price cutting. Now, coal marketing must be recognized in its "true leadership role," Daniel said. Marketing people must know when to use spot sales to balance production objectives and maintain cost-effective-

Jan 1, 1986

By R. B. Lantz

Low Froude Number (Fr) theory* predicts that stably-stratified fl& around a terrain obstacle will divide into a lower layer passing essentially horizontally around the obstacle and an upper layer passing essentially over the obstacle. The prediction was formulated by Sheppard (1956) and Drazin (1961) and confirmed experimentally in the towing tank model d experiments of Hunt et a1 (1978) and the atmospheric full scale experiments of the US EPA Complex Terrain Model Development Program (1982- 1985). The US EPA Complex Terrain Dispersion Model, currently under development, employs the layering principle with the flow in each layer calculated independently by potential flow (PF) theory after the layer thicknesses are established according to a simple function of Fr, i.e., Hc /H = 1 - Fr where Hc is the dividing streamline freight and E is the obstacle height. Use of PF theory in the CTDM is attractive because numerical solutions can be obtained simply and economically, as compared to lengthy Navier-Stokes (N-S) solutions, but realism is sacrificed in creating a surface of discontinuity between the tm layers and eliminating the effects of shear and gravity in each layer.

Jan 1, 1986

By T. Burchett, F. Stanley, K. McGough, G. Luttrell

The vast majority of U.S. coal preparation plants utilize screen-bowl centrifuges to dewater their fine clean coal products. In light of this popularity, researchers at Virginia Tech have engaged in a variety of laboratory and industrial field test programs to develop technological enhancements that have the potential to further improve the performance of this important solid-liquid separation process. These enhancements, which include simple design modifications and new reagent packages, have been shown to significantly improve solids recovery and reduce product moisture in several experimental trials.

Jan 1, 2006

By Brian Gettinger, Jared Barber, Richard Weatherly, Shannon Dunne, Jeff Masek, Chuck Wolf, Fazle Rabbi, Jack Canfield

During Hurricane Harvey over 60% of the 39 WWTPs, including the low-lying 25 MGD Sims North WWTP, and one third of the 382 lift stations owned and operated by the City of Houston were flooded resulting in extensive facility damage, loss of service and uncontrolled release of untreated wastewater into bayous and creeks. In response, the City has embarked on an effort to improve system resiliency by consolidating at-risk facilities with a network of deep sewer tunnels. These tunnels will provide secondary benefits to the collection system of augmenting the capacity of the existing 6,000 miles of sewer mains and lowering the collection system profile in poor performing areas. Investigations on the cost to mitigate the flood damages by raising the liquid stream processes at the Sims North WWTP is estimated at nearly $450 million. Instead of spending $450 million to raise the plant, the funds will be directed to providing a more robust and resilient wastewater system for the Sims basin area of Houston. The backbone of this new system is a 4.5-mile-long, 110 inch diameter deep gravity sewer tunnel that will convert a system heavily reliant on distributed lift stations to a majority gravity system with a deep consolidated lift station at the Sims South WWTP. This will also allow the City to address the flood prone infrastructure at Sims North and consolidate its operations into a single permitted outfall for this collection system. This approach is the outcome of a team effort focused on maximizing system resiliency and sustainability for the next 100 years. By thinking outside the box, the City of Houston will not only mitigate the flooding risk at Sims North WWTP, but also solve regulatory and operational challenges throughout the sewershed and deliver a winwin on multiple levels.

Jun 13, 2021

By William Kohan

The industrial grinding process has undergone changes to better address the market and economic needs. Fine grinding of dry materials has developed to the point where classifying linings and fine ball charges improve mill efficiencies. Roller mills as well have wide acceptance due to their power efficiencies. The mill, by its nature, cannot provide the specific particle size or range of sizes which are required for further processing or final use. Therefore, various separators are operated in conjunction with the mill to control particle size. The sizing device helps minimize over grinding and control top size. Rising energy costs combined with increasingly tighter quality specifications have led to increasing study of the grinding and separation process.

Jan 1, 1985

By J. D. McKay

Continuous column flotation parameter testing, to improve operating methodologies, using coarse bubbles on fluorite ore from Nevada, revealed that retention time is the predominant factor affecting column flotation fluorite recoveries. Column height and feed injection location affected fluorite grades and recoveries because they affected particle retention times in the collection and cleaning zones. Other parameters tested, including froth depth, wash water addition, and axial mixing, showed varying results. Four defined zones within the column were found to have characteristic rates of upgrading per vertical foot. Fluorite-gangue separation was more efficient in a column than in a conventional cell at all particle sizes.

Jan 1, 1987

By Rodney R. Krause

In attempting to tell the general public about the coal industry's land reclamation efforts, we have often said, "We're not doing things by the book, because we're still writing it." Like any good catchphrase, the statement is not only striking but true. It is particularly true in the mountains of Appalachia, where the problems of mining; and of reclamation are made more intense by the nature of the terrain. Mining and reclaiming the land "by the book' --which is to say by the methods of contour mining traditionally used in hill country--hasn't worked too well. So a lot of conscientious coal operators and associations are trying new methods--new ways of mining, new machines for seeding and planting, and new species to seed. Not all their experience can be transplanted to other areas, and of course I don't believe that Appalachia is the only place where new methods are being developed. Nevertheless, there's enough action in Appalachia to make a detailed examination rewarding, so let's focus on the hills to see what's new.

Jan 1, 1970

By Victoria Vaccarezza, Corby Anderson

The demand for rare earth elements for everyday technology and applications has initiated much research into the extraction and recovery of these rare earth elements. An otherwise unknown group of minerals, eudialyte is a zircon silicate consisting of rare earth oxides (REO), contained in a unique mineral structure and represented by a complex chemical formula. Research into extraction and recovery of rare earth elements involves various beneficiation and hydrometallurgical techniques. The goal of beneficiation being to efficiently liberate and upgrade the REO content, followed by hydrometallurgy to extract the desired elements. This overview will discuss previous research on treating eudialyte group minerals via different mineral processing and extraction techniques.

By G. P. Salas

I.- In order to keep pace feeding its fast growing population, Mexico with only about 20% of its surface suitable for intensive agriculture, will need the application of modern foodgrowing techniques. To assure greater crop yields it will be necessary to apply more fertilizers than used at present (yearly average of 29 Kgs/hectare)** For its fertilizers production Mexico still depends mostly on imports of phosphate concentrates from Florida, U.S.A., Morocco and Spain. To reduce or eliminate this dependence on foreign providers, the Consejo de Recursos Minerales -a Federal Government exploration Institute- started in 1974 an exhaustive exploration program for phosphate deposits more amenable to commercial exploitation than the phosphatic limestones contained within the La Caja Formation of Upper Jurassic, found along the Sierra Madre Oriental. After studying literature on the origin and deposition of marine phosphate and visits to deposits in Florida, U.S.A., the Baja California peninsula was selected as most favorable for starting this program because of its geologic and sedimentary history and also for its geographic location, where the cold California and warm Counterequatorial currents meet. Exploration activities executed by FORNOS, S. A. (1956) led to the disco very of low grade phosphate (3 to 5% P2O5) in the recent beach sands along the Bahia de Magdalena (Fig. # 1). In his doctoral thesis Bruno D'Anglejan Chatillon (1965) reports the presence of nodular phosphate on the continental shelf, between Isla Margarita and the Vizcaino peninsula. He estimated reserves of up to 1.5 million tons. A Mexican-American marine exploration company attempted in 1966 the evaluation of this deposit with negative results.

Jan 1, 1978