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By Harry Sutcliffe

THE PROBLEM Two and a half years have gone by since the December, 1976 Civil Engineering article on subway costs caused such a furore. What has happened in this interval? Even after discounting the crushing inflation rate, costs are still increasing, and there is no sign of a turndown, even in the rate of increase. Some steps outlined in the article have been taken. In April this year, the first D.O.T.-sponsored Peer Review Group, made up of managers of other transit properties, met in Boston to review MBTA's $500 million Red Line Extension-Northwest for cost effectiveness. While the impact of a review at the end of the design phase, with substantial segments under contract, cannot be as effective as a review early in the design phase, it is nevertheless a start. This first meeting will be followed by a review of Boston's Orange Line relocation, the final design for which is just underway. In the industry at large two facts are evident: 1. We are failing to reduce underground construction costs. 2. Underground construction is in danger of pricing itself out of the market place. It has always been a greater challenge to design a Chevvy than to design a Cadillac, but it is the Chevvy we need today. Much attention has been focussed in the past on engineering design in the narrow sense: areas such as ground loading conditions and concrete design. This paper will attempt to make the case that costs in urban underground construction are primarily outside the area of structural

Jan 1, 1979

By Robert G. Lundquist

REAM (for Rapid Excavation And Mining) is a method of rock fragmentation by high-velocity projectile impact developed by Physics International Company. This paper reports the results of field testing over the last two years. The success of the method is based on the fact that the amount of rock broken per shot scales nonlinearly with projectile impact energy. Thus, high energy impact yields spectacularly low specific energies for rock breakage. The field work reported used 90- and 105-mm military guns to accelerate 8-1/2 and 10-pound concrete and steel projectiles to velocities of 5000 to 5500 fps. All tests were performed in a competent 25,000 psi granodiorite at Hope Valley, California. During the first year of field testing 26 feet of 13-foot-diameter tunnel were produced with the 105-mm gun. The first 20 feet of this tunnel were line-drilled to aid in producing a stable portal. During the second year the tunnel was extended an additional 29 feet using the 90-mm gun. The 55-foot tunnel was produced by 590 shots. Between 1-1/4 and 1-1/2 tons of granite were broken by each shot. A silenced 90-mm gun was placed underground and the tunnel portal closed with a steel barrier. Overpressures of less than 1 psi were measured on the inside of the barrier, corresponding to an impulse noise of about 170 db. The muck produced was similar to drill and blast muck. Overbreak and ground support problems appeared to be less than with drill and blast. The contour of the tunnel was easily controlled using the 90-mm gun; the tests were also conducted using a 57-mm gun for trimming. Projections indicate that advance rates with REAM will be three to seven times faster than drill and blast, at less than two-thirds the cost. This is based on the development of a fully integrated continuous system and an inexpensive propellant giving a total expendables cost of less than $3 per shot. Other applications of the REAM technology are found in secondary breakage for open pit mining, in drilling large diameter holes, and in underground mining for longwall mining, overhand stoping, and raising.

Jan 1, 1974

By I. Loomis, D. Rachmad, I. Duckworth

During the past two years the Underground Mine Ventilation Group at PT Freeport Indonesia has undertaken to upgrade their Hygiene Laboratory. This process has included upgrading equipment for dust sampling and gas monitoring, as well as procurement of an OCEC analyzer for Diesel Particulate Matter analysis. While the laboratory equipment represents one factor, these changes have also required re-evaluation of the sampling protocols and the burden of ventilation monitoring personnel. This paper provides a review of these experiences.

Jan 1, 2006

By Kirk H. P. E. McDaniel, Mark T. Strever, Keith G. Jr. Wallace

This paper presents the design and installation of an underground ventilation remote monitoring and control system at the Waste Isolation Pilot Plant. This facility is designed to demonstrate safe underground disposal of U.S. defense generated transuranic nuclear waste. To improve the operability of the ventilation system, an underground remote monitoring and control system was designed and installed. The system consists of 15 air velocity sensors and 8 differential pressure sensors strategically located throughout the underground facility providing real-time data regarding the status of the ventilation system. In addition, a control system was installed on the main underground air regulators. The regulator control system gives indication of the regulator position and can be controlled either locally or remotely. The sensor output is displayed locally and at a central surface location through the site-wide Central Monitoring System (CMS). The CMS operator can review all sensor data and can remotely operate the main underground regulators. Furthermore, the Virtual Address Extension (VAX) network allows the ventilation engineer to retrieve real-time ventilation data on his personal computer located in his workstation. This paper describes the types of sensors selected, the installation of the instrumentation, and the initial operation of the remote monitoring system.

Jan 1, 1995

By Kenneth R. Dickson, I. Michael Gowring

This paper describes the underground work associated with the North Fork Stanislaus River Hydroelectric Development currently being constructed by Sierra Constructors for the Calaveras County Water District in California under a turnkey contract. Sierra Constructors is a joint venture of the Guy F. Atkinson Construction Company (sponsor) of South San Francisco, and the Harrison Western Corporation of Denver. Notable features of this project include the exceptionally high performance achieved by the 5.5m diameter Robbins tunneling machine and the 675m deep shaft pilot hole which was successfully realigned using oilfield directional drilling techniques. Other features include 3.7m and 4.3m diameter machine-excavated tunnels and various conventionally excavated tunnels constructed over a wide geographical area and diverse climatic conditions.

Jan 1, 1987

By Siegmund Babendererde

Introduction Lyon, with 1.1 million inhabitants, is the third largest city in France after Paris and Marseille. It is a lively industrial centre. Lyon lies at the intersection of many transport routes and at the fluence of Rhone and Saone. Like all large cities, Lyon is attempting to alleviate inner city traffic problems by constructing a metro. Metro construction in Lyon began with tunnels built by cut and cover methods along the streets. Deep diaphram walls, which were back anchored and toed into imperveous strata, formed the excavation walls. It is a very economic and simple method. However during the construction period, it has the disavantage of strangling urban life for several years. It is therefore increasingly being replaced by subsurface tunnelling methods. As it was decided to build the metro tunnel between the Guillotiere and St. Jean stations, and thus cross under the Rhone and Saone, the client, Semaly, put the contract out for a competitive tender in which the general parameters were defined. Line, level and construction method were left to the contractor. There was an extensive examination of the tenders, during which reference projects from competitors in Japan were visited, as well as in Germany. Finally the consortium of Dragages, Campenon Bernard, Colas and Hochtief was awarded the contract to drive this tunnel section with an hydro-shield and an extruded steel fibre concrete lining, a Hochtief design.

Jan 1, 1987

By Dipl. -Ing. H. -J. Sager

The ‘Westerschelde Tunnel’ underpasses the estuary of the Schelde in the Netherlands. The tunnel will consist of two tubes which are driven by two hydroshields (slurry shields). The tunnels will each have a length of approx. 6.6km and a bore-diameter of 11.33 m. Demanding ground conditions had to be considered during the design of the shield machines. Loose sands, extensive clay formations and high ground water pressures of up to 6.5 bar will be encountered during the tunnel drive. The tunnelling activities will start in the middle of 1999 and are scheduled to end by the end of 2001.

Jan 1, 1999

By Jon “Ike” Isaacson, Frank Perrone, Eric Prantil

"Tunneling through an urban environment carries many inherent risks to the immediate local infrastructure and subsequently to the project stakeholders. On the CQ031 Contract of the East Side Access Project in Queens, New York, twin 22.5’ diameter Herrenknecht Slurry TBMs were mined within close proximity to many infrastructure assets, with cover of less than half a shield diameter at times. Multiple public bridges and critical railroad infrastructure including catenary poles and signal towers supporting the busiest rail interlocking in the United States required underpinning systems. The support program for these structures was refined over the course of the four tunnel drives. It is the intent of this paper to show how the interaction between the temporary structures, instrumentation monitoring plan, and risk assessment program melded to provide a system which the owner, contractor, and designer relied on as a tool to ensure the project success without impacting the public surroundings. PROJECT BACKGROUND The East Side Access (ESA) megaproject located in New York City, N.Y is a multi billion dollar program for the Metropolitan Transit Authority Capital Construction (MTACC) with the main goal of bringing the Long Island Railroad (LIRR) commuter rail to Grand Central Station located in the heart of Midtown Manhattan. When completed, the project will significantly reduce congestion both into and out of Penn Station, the current terminus of the LIRR. In order to accomplish this, multiple contracts of varying scope are required to operate simultaneously in both Queens, N.Y and Manhattan. In 2009, the CQ031 Queens Bored Tunnels Contract was awarded to the joint venture of Granite Construction Northeast, Traylor Bros. Inc., and Frontier Kemper (G.T.F). The main scope of this contract was to excavate four segmentally lined soft ground tunnels underneath the Sunnyside Rail Yard in Queens, New York. Additional scope of work included the construction of a tunnel approach structure, electrical substation, and multipurpose ventilation and egress facility."

Jan 1, 2016

By Kenneth R. Ware

I INTRODUCTION The Washington Metropolitan Area Transit Authorities (WMATA) rapid transit system (METRO), currently under construction, will have a total length of 98 miles. Forty-eight of these miles are underground and require either open cut excavations or tunnels. Despite stringent construction controls, it is inevitable that some ground settlement will occur adjacent to the deep open cut earth excavations and large diameter earth tunnels. It is therefore essential to underpin nearby important structures to prevent excessive differential settlements and Fig. 1 presents the METRO criteria for this underpinning. This paper describes the underpinning methods currently used on METRO and evaluates the effectiveness of each method. II DESCRIPTION OF SUBSURFACE STRATA The foundation materials in the Washington, D.C. area are extremely variable. Fig. 2 presents an idealized profile showing typical subsurface strata. The engineering properties of each stratum have been determined by extensive exploration and testing programs. Fill: Washington, D.C. fills consist of every variety of soil and rubble. They are not important to this study because no underpinning is founded on fill material. Terrace Deposits: Formed in outwash plains during the glacier period, these deposits are composed of random layers of either sand 1 The writings and opinions expressed herein are solely those of the author and do not necessarily reflect those of WMATA.

Jan 1, 1974

By Thomas Schwind, Elmar Feigl, Gerald Skalla, Angelos Gakis

Cedarvale station was constructed as part of the Eglinton Crosstown Light Rail Line, under the operational Yonge-University Line Subway box of Toronto Transit Commission (TTC). The station was constructed as an open-cut, which necessitated the underpinning of the existing TTC box to minimize the impact on the Subway and allow its unhindered operation. Six mined galleries, 4 m wide by 2.75 m high, were excavated sequentially (SEM) immediately under the existing box, to provide the required space for the installation of the main underpinning beams. This novel solution was executed successfully providing quick access for the main excavation works to commence.

Dec 1, 2022

By Pieter Barendsen

INTRODUCTION One of the main problems in tunneling without the use of explosives lies in the development of tools which, at an economically acceptable level, are capable of continuous breakage of the rock, resulting in a fragmentation suitable for a smooth, uninterrupted transportation of the muck away from the tunnel face. Tools employed on tunneling machines have, so far, always been of the mechanical kind which break up the rock by a crushing and shearing action. Other methods of rock breaking are possible but, even if some of them have reached the laboratory testing stage, nearly all of them are still too "exotic" to be of any practical use in the immediate future. One must admit, however, that some highly interesting results are beginning to be reported from the USA on the use of high pressure water jets for the destruction of rock through erosion, a field pioneered in Europe(USSR and Great Britain). Mechanical breakage of the rock is effected by inducing stresses exceeding its compressive/shear strength, by loading it with a wedge of cone shaped tool, until cracks are formed and chips loosened. In order to allow the tools to act upon the rock face continuously, they are commonly shaped as rotating bodies, "roller bits" or "disc cutters", spinning freely and mounted on a revolving boring head of tunnel diameter. The thrust of the tools against the face is generally exerted in a direction which is parallel to the tunnel axis.

Jan 1, 1997

By John E. Crawford

A year ago, if I had the pleasure of addressing you, I would have discussed ocean mineral resources from a promotional standpoint. I would have described exciting indications of mammoth tonnages of sea-floor industrial minerals. I would have attempted to fire your imaginations as to the potential of a nation having the technologic know-how to exploit its submerged boundaries. As a first step toward this capability, I would have solicited your support for a Bureau of Mines? program aimed at determining the industrial worth of marine minerals and devising techniques and hard- ware for their recovery. We still need your support, but recently we have ventured out of the realm of planning and into your Government's first program in marine mineral engineering. Today, I wish to describe what we have done within the framework of existing research problems and our possible goals. I will be brief so as to allow ample time for questions, and I can do this with confidence because our program is so new that I need not be chagrined at not having all the answers.

Jan 1, 1965

By M. L. Free

Acid consumption in copper heap leaching is determined by the minerals present in the ore. Gangue minerals such as biotite and chlorite consume acid together with copper-bearing minerals such as chrysocolla and malachite. Acid consumption is affected by the rate of acid application and the particle size. Some gangue minerals undergo alterations and cause precipitate formation during acid leaching. Other minerals form due to precipitation as dissolved ion concentrations from a variety of mineral sources combine to exceed saturation levels. Copper recovery is related to all of these events. This study presents information on acid consumption of various gangue minerals as well as data for copper recovery from an associated copper ore.

Jan 1, 2010

By F. S. Kendorski

Several startup or longtime underground stone mines have experienced unanticipated roof control difficulties due to the variable geologic character of the roof strata. Careful mapping of roof conditions, and identification of controlling geologic and mine geometric factors, lead to an understanding of the mechanisms causing roof problems. Factors such as unexpected rolls of the roof strata resulting in a gradual change from strong to weak roof; encountering open water-filled master joints; roof strata delamination due to internal water pressures; local karst features with mud, sand, and water hazards; and sudden loss of limestone roof due to paleo-channel erosion are some recent problems described. Strategies for overcoming these problems are discussed and detailed.

Jan 1, 2002

By John F. Parmeter

On August 29, 1989, the Department of Labor, Mine Safety and Health Administration (MSHA), published a Federal Register concerning a new proposed rule on air quality, chemical substances and respiratory protection standards. As of this writing, their proposed rule has not become a standard. However, with little revision it could be expected to become a standard, and we in the mining industry will be expected to adhere to and enforce it.

Jan 1, 1991

By E. C. Winegartner

In producing and selling coal, the coal company is faced with many different parameters by which the quality of its product is evaluated. One type, which we choose to call the economic parameters, includes moisture, ash, sulfur, and Btu's. These are reasonably well understood by both the coal supplier and the customer, and the dollar values can be placed on them. This is the group of parameters of primary interest to most purchasing agents buying coal. A second group of parameters governs how the coal will behave in the boiler itself and is of primary concern to the engineers designing the boiler and to the men who must operate and maintain it. Since we have not yet learned to put dollar values on these parameters, they generally show up in coal contracts simply as cutoff points, the purchaser simply saying that he will not accept coal outside of certain limits.

Jan 1, 1975

By Hemendra N. Kalia

The target to double the coal production by 1995 presents a formidable challenge to the coal mining industry. The mines of future, probably will be located in relatively difficult geological environment because of the exhaustion of the well defined bedded and easily minable deposits. To compound the problems of mining industry will be the reliance of power plants need for coal. The coal must reach the power plants on schedule to avoid expensive blackouts and brown¬outs. It will be imperative that the mines operate without interruptions and at designed capacities. The parameters which have been traditionally responsible for the interrup¬tions of production are: breakdown of production machinery, labor management relations and geological anomalies. Of these three problems, solutions for the first two can be arrived at by developing procedures to correct the situation. A planned maintenance and preventive maintenance program will go a long way in minimizing the equipment breakdowns. Labor relations will eventually improve as the miners begin to enjoy long-term employment. However, with the geological problems, the situation will probably continue to deteriorate and would require careful planning to minimize the impact of geological problems on production and safety. Some of the geological aspects which interfere with production are: faults, washouts, slips and slickensides, water bearing overlying strata, impuri¬ties in the coal seam, and presence of expansive clays in the coal floor. The design of large capacity mines will have to incorporate the geological distur¬bances and mine through them it may become very uneconomical to abandon producing sections because of the presence of the geological anomalies. This paper discus¬ses the geological aspects of coal mining which should receive consideration from the inception of the mining ventures. Pertinent geological aspects are discussed to develop the data base which will aid in evolving safe and efficient mine layouts.

Jan 1, 1976

By K. L. Lownie

For research and test data to serve a useful purpose, it is essential that it be derived from some known standard test procedure that allows for comparative analysis as well as independent replication and verification. Fan performance data provided by manufacturers is not absolute, and is influenced by the geometry of the test installation. For these reasons, fan test standards have been prepared in order to establish a clearly defined test procedure that allows for comparison of different fan designs, and also allows for the independent verification of test data. Internationally recognized Standards such as BS848, ISO5801, and AMCA 210 etc. are highly prescriptive, and precisely specify test duct configurations, measurement procedures, measurement planes and instrumentation to be used. Provided the laboratory tests are conducted strictly in accordance with the relevant Standard, the performance data will accurately reflect fan performance within the appropriate tolerances for efficiency, pressure and flow when tested in the defined configuration. Major differences in performance exist between a fan tested in accordance with a Fan Test Standard, and an identical fan installed in a mine ventilation system. The aerodynamic performance of any fan will be influenced by the quality of the fan manufacture, the flow system within which it is operating, the location of measurement planes, and the system stability. The flow distributions present in a standardized Laboratory test are unlikely to be repeated in mine ventilation systems, and this will also disadvantage fan performance. Unless the fan supplier takes all of these influences into account, there will an inevitable reduction in fan aerodynamic performance, and the end user will experience a shortfall in expected flow through the mine. The effect on fan performance can range from minor inconvenience to catastrophic fan failure resulting in major rectification costs and significant loss of mine production.

Jan 1, 2009

By Kevin Andrews, Terry Hamric, Scott Nelson

"Mining conditions in underground coal mines are dictated by the environment in which the coal seams were geologically deposited. Depositional features can change rapidly, significantly affecting mining conditions. Mine geologists understand factors affecting mining conditions, predict future conditions, and provide guidance to mine management. A case study demonstrates how a mine in Appalachia merged an understanding of depositional environments with mining conditions and drilling data to make informed decisions as the mine encountered geologic anomalies. The assessment included drilling, mapping of geologic hazards and mine productivity, and creation of a conceptual depositional model. Metallurgical coal quality and clean tons per foot served as incentives for continued advance. Mining in the south was historically favorable, with good production and advance rates. As mining advanced north, changing geologic conditions caused the upper seam split to abruptly disappear. The mine ramped down into the lower seam split. Mining in the north area encountered unfavorable conditions, including transition roof, “horsebacks,” sandstone intrusions, roof rolls, and bony floor, resulting in low rates of mining advance. The mine geologist characterized the features and created a predictive model for future mining. Most of the adverse conditions were attributed to the coal in the north being part of an incised, transgressive valley fill environment, as compared to the favorable conditions in the south resulting from a floodplain depositional environment. Geologic conditions, low productivity, and unfavorable future predicted conditions in the north ultimately resulted in mine closure and reallocation of resources to a new mine with better forecasted conditions.INTRODUCTIONThe role of a geologist in assisting coal mining operations to understand and predict the impact of varying geological factors on mining productivity is a critical one, especially when management decisions must be made about the future prospects of a mine operating in difficult conditions. Chase, Newman, and Rusnak (2006) provide a very thorough discussion of the evolution of the role of the coal mine geologist and emphasizes the importance of understanding geology with regard to mine management decisions. Using actual mining performance data to determine which geologic factors are the most critical for mining is a powerful tool for making informed mine management decisions. For example, Nelson, Mullennex, and Miller (1988) provide a case study of analyzing the geologic factors impacting productivity of a Kentucky longwall mine to predict future mining conditions for the operation. In that case, the difficult geologic factors for longwall mining were prevalent across much of the remaining permit area and, in response, mine management converted the operation from a longwall operation to a continuous miner (CM) operation to better adapt to the geology. In another example, Keim and Miller (1999) evaluated geologic conditions impacting a West Virginia longwall mine. In both examples, significant geotechnical and geological information was available, including the opportunity to compare predicted mining conditions against actual conditions as mining progressed. Numerous examples of advanced Geologic Hazard Mapping (GHM) methodologies have come from government agencies and academia. For example, development of the Coal Mine Roof Rating (CMRR) system (Molinda and Mark, 1994) provided a standard means for geologists and engineers to communicate quantitatively with regard to mine roof conditions, and the introduction of the Stability Mapping System (SMS) provided an efficient means for analyzing numerous factors affecting coal mine stability (Wang and Heasley, 2005)."

Jan 1, 2019

By REHMAN ATTA UR, Kwame Awuah-Offei

This work evaluated the effects of bucket orientation and operating parameters on resistive forces and penetration for rubber-tire loaders (RTLs), such as load-haul-dumps (LHDs) and front-end loaders (FELs). The work used a 1:16 scale LHD model to test an RTL bucket operating at different levels of traction (tractive effort), speed, digging height and rake angles in a full factorial design experiment. The test was repeated on two muck piles with different particle sizes, and generalized regression modeling was applied to test the association of rake angle, tractive effort, speed and digging height on penetration and resistive forces for RTL buckets. The results show that speed and tractive effort are more important in explaining RTL penetration and resistive forces than height above the floor and rake angle. Speed, tractive effort and height above the floor are positively correlated to bucket penetration, whereas the rake angle is negatively correlated to penetration. Similarly, speed, tractive effort, rake angle and height above the floor are all positively correlated to resistive forces incurred during initial penetration. The results show that the combined effect of speed and tractive effort is negatively correlated to penetration and resistive forces — a novel finding that enhances our understanding of RTL loading. The results also show that the effects of speed, tractive effort and height above the floor all change with changes in particle sizes. This work provides insights into the effects of rake angle, height above the floor, tractive effort and speed on penetration and resistive forces for RTLs to facilitate better design and efficient use of these loaders.