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By Sigmund D. Schwarz

INTRODUCTION In late 1970, an experimental geophysical program was undertaken at the Lake Huron Tunnel for the purpose of developing a geophysical technique that could be applied to determining the thickness of rock above the crown of the tunnel and identifying anomalous geologic conditions ahead of the face as the tunnel was advanced. The Lake Huron Tunnel is an 18.5 foot diameter machine bored tunnel having a total length of approximately 6 miles. The easternmost 4.5 mile section of the tunnel extends offshore beneath Lake Huron. At the time this study was started, approximately 1.5 miles of bore remained to be completed at the east end of the project. The tunnel is part of a raw water intake for the City of Detroit water supply. The Lake Huron Tunnel is bored in Antrim shale, a dense marine shale of Mississippian or Devonian age. The west end of the project encountered banded brown shale containing numerous calcareous concretions ranging in size from a few inches to more than 16 feet in diameter. As the tunnel was advanced in an easterly direction, a transition was encountered into very uniform gray shale. One set of prominent vertical joints was encountered with a strike running approximately 15 to 20 degrees askew of the tunnel axis. Bedding is essentially flat. Variable quantities of salt water and natural gas occur in the rock. The results of exploratory drilling carried out for preliminary design studies indicated that as little as 30 to 35 feet of rock cover could be expected under the lake at the east end of the project.

Jan 1, 1997

By Tom Martin

Mega projects present unique challenges with regard to estimating costs. With such projects, which may span decades, these challenges often begin as soon as a project is conceived. The importance of having a sound, resource based estimate avail-able early in the process cannot be overstated because it provides the basis for ongoing project decisions. For the final phase of providing an updated cost estimate, often while bidding by contractors is underway, the Engineer?s Estimate (EE) must incorporate present market conditions; account for possible volatile material price swings; be based on actual labor and fringe costs; rely on meaningful productivity rates; and accommodate any recent technology advances while identifying and allowing for risk factors. This paper explains the benefits associated with consultants adopting a contractor?s estimating approach when preparing the Engineer?s Estimate on mega projects like the various tunneling projects in New York City.

By Martin Stone

Industrialized countries, particularly the United States and the United Kingdom, remain at the forefront of international efforts to control the potential disruption from computer malfunctions caused by the date change from1999 to 2000 — widely known as the millennium bug or Y2K. Disruption is least likely in the developed world, including the United States, Canada, western Europe, Japan and Australasia. However, the picture is potentially different in developing countries where many mining companies operate. The less developed the country, the greater the chance of some form of Y2K-linked disruption.

Jan 1, 1999

By Chris Tattersall, Tomyuki Kudo, Peter Raleigh, Nestor Garavelli, Steve Redmond, Michael J. Lehnen

Twin bore running tunnels driven approximately 4,500 route feet by a Mitsubishi Heavy Industries (MHI) EPB Tunnel Boring Machine link the West Portal and East Portal on this complex Light Rail Project. One third along the way, the TBM arrives at the Beacon Hill Station which is the deepest underground “binocular” station of its kind in North America and then “walks-across” the station to be re-launched on the other side to complete the drive. This paper discusses briefly the layout and design considerations but then focuses more deeply on the approach by the Contractor to drive and supply the tunnel. The paper addresses the approach used to launch, re-launch and recover the TBM and touches briefly on muck volume control and monitoring plus settlement monitoring and the performance achieved. Also of interest is a unique solution to a difficult launch situation involving a secant pile tieback wall designed with several rows of double I-beam steel walers spanning the eye at the West Portal under the I-5 freeway.

Jan 1, 2007

By W. O. Kerr

As in other industries, companies engaged in mining and extraction use and develop intellectual property (?IP?) in the form of new technologies or production processes. The development of IP assets in mining may occur as a byproduct of ongoing operations, or result from investment in dedicated R&D efforts. New technology may lower costs, increase quality of output, and/or increase operational efficiency or safety. Key business questions with respect to any new technology are how best to use IP assets, how to protect them and how to derive value from them. IP assets can provide a competitive advantage to a developing firm that uses the technology to improve its operating results. The developing firm can preclude others from using the technology if it believes that is the best way to exploit the technology?s value. Or, it can be shared with others taking care to ensure rights are maintained, thereby generating royalty income or strategic value through cross licensing or other business relationships. Either way, in order to fully realize the maximum economic benefit, innovators must protect the IP assets and control their dissemination.

Jan 1, 2012

As noted by D.W. Fuerstenau in his Plenary Lecture at the Conference on Extractive Metallurgy of Gold and Base Metals, Kalgoorlie, Australia, "Com¬minution of solids is surely one of the oldest technologies that, even in this day and age of DNAs, chips and space exploration, continues to challenge our scientific acumen and engineering ingenuity." Thus, the fundamentals of comminution continue to receive a great deal of attention in the literature. This was particularly true in 1992 with the publication of the proceedings from the SME-sponsored symposium, Comminution Theory and Practice. Papers covering topics ranging from liberation to comminution fundamentals to novel size reduction techniques are included in this review. Liberation Liberation continued to be a prime area of research interest, not only in terms of liberation modeling, but also in understanding the basic mechanisms involved in mineral liberation. King (Comminution - Theory and Practice, pp. 3-15) described a method for determining the interphase area between mineral grains. He showed how the mea¬surement of interphase area before and after comminution could be used to determine the presence or absence of intergranular fracture. Lin, Miller and Cortes (Kona, Vol. 7) discussed the use of computed tomography (CT) as a nondestructive means of investigating three-dimensional particle composition. The use of this technique in constructing coal washability curves from CT data was presented.

Jan 1, 1993

By Steve Kral

Amax Coal Industries Inc.'s Delta Mine is a medium-sized. high-sulfur coal producer that has lived up to the challenges posed by nearly six decades of a highly competitive domestic coal market. The mine now faces one of its biggest challenges - the same one staring at the dozens of other high-sulfur producers in the Midwest - the Clean Air Act Amendments of 1990. The 59-year-old mine, located in the coal fields of southern Illinois, has remained one of the state's oldest continuously operating mines by rolling with the ups and downs of the coal market and by incorporating new technologies and innovative productivity improvements into its operation.

Jan 1, 1993

By Richard J. Stoehr

In his time on earth, man has mined about 93.3 kt (3 billion oz) of gold. About one-half of this has been produced in the past 35 years. Roughly one-third of this gold is held as reserve in Central Banks. One-third held is in personal reserves. And one-third is held as jewelry or other fabricated products. The world per capita availability of mined gold is increasing. There are many forces shaping gold's future. Gold currently has a favorable exchange ratio. This is encouraging many new gold mining developments. Production is increasing and new recovery techniques are surfacing. The use of gold in the financial markets is increasing in some unique ways. And gold is again fulfilling its role as a universal money, making its future predictable. Gold Today Man is currently mining gold at the rate of about 1.4 kt/a (44 million oz per year). This adds about 1.5% of newly mined gold to the total supply each year. This production plays a small role in the pricing mechanisms since much of the 93.3 kt (3 billion oz) mined is available to the market in some form. The 31.1 kt (1 billion oz) held by central and international banking

Jan 11, 1984

By Matthew E. Fowler

The Central Subway will extend the recently completed 8.2-km long Third Street Light Rail line another 2.7 km north through the Union Square shopping district to Chinatown with a concourse-to-concourse connection to the Powell Street BART Station. One mined and two cut-and-cover subway stations are planned. Particular challenges include: tunneling under existing tunnels; variable ground conditions ranging from saturated alluvium to fractured bedrock; a congested urban setting and large-span caverns. This paper gives an overview of the project as it stands midway through the preliminary engineering stage along with a discussion of the rationale and design approaches that are being used to address the construction challenges of restoring light rail service in the most densely developed areas of San Francisco.

Jan 1, 2008

By J. Greg Sanchez

The New South Ferry Terminal in the New York City Transit system represents an important milestone for the city. This is the first station designed and built in the 21st century. The design of the fire safety system included relying on Computational Fluid Dynamics to analyze the dispersion of heat and smoke, and modelling of people egress to determine the egress requirements. The project also looked into how to protect the structure from the heat exposure in order to meet the fire rating requirements. This paper provides an overview of the fire safety design approach taken to design the new South Ferry Terminal station in lower Manhattan and looks into fire modelling, structural fire protection, and station evacuation.

Jan 1, 2008

By William Reininger

Microtunneling provides a necessary solution for multiple utility crossings associated with the New York Metropolitan Transportation Authority Capital Construction Company?s (MTACC) Eastside Access Project for the Long Island Rail Road. Construction of four TBM tunnels and their approach structures at the eastern end of the project in Sunnyside, Queens required significant modification and expansion of the railroad infrastructure at this location. Maintenance of railroad traffic during project construction is a principal requirement. As a consequence fourteen (14) utility crossing segments are being installed under active traffic by microtunneling methods. Microtunnels were installed in a variety of conditions including depths, types of soils and construction restraints.

By Mohammad R. Jafari

The Camp Dresser & McKee (CDM)/Hatch Mott MacDonald (HMM) joint venture has been engaged by the New York City Economic Development Corporation (NYCEDC) to provide engineering ser-vices in connection with the replacement of two existing siphons which cross New York Harbor between Staten Island and Brooklyn. The project involves the construction of a 72-inch diameter pipeline within a 12-foot diameter tunnel beneath the New York Harbor. The tunnel will be constructed using either slurry or an earth pressure balanced (EPB) tunnel boring machine (TBM). This paper presents the results of an extensive geotechnical field and laboratory testing program including advanced frozen soil tests (uniaxial compressive strength tests, triaxial tests, and uniaxial creep tests), in-situ vane shear and pressure meter testing, and a marine geophysical survey (seismic reflection technique) to ascertain the complex subsurface conditions along the tunnel alignment and shaft locations. The paper will also discuss the design and construction aspects and the challenges associated with each component of this project.

Jan 1, 2008

By V. Svalbonas

When the Trelleborg Divisions of Boliden Allis and Mineral Processing Systems (MPSI) merged, a unique opportunity occurred for two independent mill fabricators to compare design pro¬cedures and the research upon which they were based. Several semiautogenuous (SAG) mill analyses are compared using Boliden Allis and MPSI methods. The differences and similarities are then used in a correlation of critical stress definitions and the acceptable design and inspection criteria. Given the opportunity to compare the total philosophies and methods of several companies involved in the design and fabrication of grinding mills, it was important to first develop the comparison method and ground rules. One option was to compare analytical methods by details such as numerical techniques and accuracies. However, this option was discarded in favor of a more general approach. The question that was finally posed was in two parts. Given an identical mill requirement: • What would be the difference in the analytical design result, and to what aspect of the analytical process could this difference be attributed? • What would be the difference in approaches to obtaining the final hardware in subcontracting, both in specifying and Quality Assurance surveillance? By using this comparative approach, questions of relative conservativeness and reliability would automatically be answered.

Jan 1, 1992

By Hiroshi Soda, Atsumi Ohno, Hiroyuki Yamazaki, Alexander McLean

INTRODUCTION The method of heat removal during a casting process strongly influences the crystal morphology of the cast product and hence the metallurgical and mechanical properties of the solidified materials. In this paper, the Ohno Continuous Casting Process (OCC) is described in terms of the casting conditions and the type of structure observed in the cast product. Significant improvements are observed in workability, fatigue strength and corrosion resistance of castings produced by the OCC method, Ohno (1988). Applications of this technique to low melting point nonferrous metals and alloys are discussed. The feasibility of the application of this technology to high melting point materials is outlined. THE OCC PROCESS The OCC process involves delivering liquid metal into a heated mold, the temperature of which is held just above the solidification temperature of the metal to be cast. This is the key point which differentiates the OCC process from the conventional continuous casting method. A schematic illustration of the OCC process is shown in Figure 1. The Formation of a Single Crystal When the mold is heated above the solidification temperature of the metal to be cast, nucleation on the mold surface is prevented and solidification takes place only at the mold exit. The heat is extracted through the product being cast by a cooling device located near the mold outlet. Crystals are formed only at the tip of the dummy bar at the start of casting, and as the dummy bar travels away with a progressively increasing speed from the mold, the position of the solid liquid interface will align with the mold exit, producing a unidirectionally

Jan 1, 1990

By E. M. Frizzell

Development of mobile crusher systems for surface mining, allowing extension of continuous conveyor haulage systems into the pit, is traced from its introduction to the present. Variations in configurations are reviewed, and the compelling reasons for using mobile crusher systems are explored.

Jan 1, 1983

By R. Kaushik

According to the U.S Department of Energy (DOE), mineral processing activities including comminution (size reduction) uses 4% of the world electrical energy consumption. Such numbers reinforce the need to invest in energy savings initiatives in order to produce more using less. ENERGY EFFICIENCY OPPORTUNITIES AND CHALLENGES IN MINING OPERATIONS In addition, DOE, in its Mining Industry Energy Bandwidth Study, has identified huge potential for energy savings for the coal, metals and mineral industries. Even knowing the overall causes of energy waste and some potential tools for remediation, mining companies may struggle to apply such tools and get the desired results due to the following reasons: ? Limited staff ? Lack of accurate economic and investment analysis to justify energy savings projects ? Lack of knowledge to identify low or no-cost savings opportunities ? Internal competition for resources According to the workforce and talent management experts, the Talent Strategy Advisors, the demand for mining engineers is expected to exceed supply by 30% by 2013. Mining personnel are likely to be burdened with increasing and varied workloads with limited training. This will result in the need for automated and simple tools to support energy efficiency activities. Mining engineers will simply not have the time and resources to create such tools, collect and analyze the data to make decisions, and track results.

Feb 27, 2013

By J. C. Stankus

Accurate evaluation of stress and geological conditions is critical to ground control design in underground openings. For a slope entry, the problem is more difficult because a slope will transverse through many different types of strata. Over the past three years, Keystone Mining Services, LLC, an affiliate company of Jennmar Corporation, has developed a new methodology designated the ?Stress, Geologic, and Support Design System (SGSsm)?. This patent pending method analyzes the stress, geology, and support design for a mine slope. It has been successfully applied in various new slopes across the United States. This paper will detail the main concepts of the methodology including: (1) Analysis of stress and geology and identification of strong, fair and weak zones along the slope; (2) Primary and supplemental support design; (3) Long term support design in the form of steel square sets or arches, and (4) Validation of the support design utilizing advanced finite element computer modeling.

Jan 1, 2011

By Ian Hutchison, Ted Sluder, Jack Caldwell, Don Moore

Introduction The Cannon mine at Wenatchee, WA has recently been brought into operation to recover gold from the sandstones of the Swauk formation. The mine is a joint venture between Asamera Minerals (US) Inc. and Breakwater Resources. A tailings impoundment was constructed to impound 2.7 to 3.6 Mt (3 to 4 million st) of tailings at 1.8 kt/a (2000 stpd) over about five years. This paper describes the design and construction of the impoundment. In particular, it describes the 100 m (300 ft) high earthfill embankment that is the main feature of the facility. Project environment The project is located on the outskirts of Wenatchee, a town of about 40,000 people. The town is situated on the flat alluvial terraces beside the Columbia River. The Cascade Mountains rise from the terraces in a series of ridges and valleys. The mine is at the foot of the Cascades. The tailings impoundment is in one of the steep valleys. The climate is mild and dry (Table 1). Site selection Twelve alternative sites within a 16-km (10-mile) radius of the mine were examined. Decision making theory was used to select the most suitable site. Advantages of the chosen site include its proximity to the mine and its low visibility from points of common public access. Also, the area was already heavily impacted by an existing silica quarry. The major disadvantage of the site is the need to pump tailings over a distance of 1.5 km (1 mile) and against a static head of 200 m (655 ft). Also, it is located in a gulch just upstream from the town of Wenatchee. Site geology The impoundment is generally underlain by interbedded sandstones and siltstones. The siltstones are often shattered. The sandstones are often friable. Both rock types are extensively jointed. Some isolated faulting of the sediments occurred before the area was covered with basalt flows. About 10,000 years ago, at the end of the ice age, the basalts were covered by 3 to 10 m (10 to 33 ft) of wind blown loess - a fine sandy clay and silt. River deposits filled the base of the valley to depths between 5 and 25 m (16 and 82 ft). Under the main part of the embankment, these materials were removed to expose bedrock. Ground water flow is generally through the more permeable layers. The permanent water table is about 5 m (16 ft) beneath the ground surface. Project and impoundment layout Figure 1 shows the layout of the mine, the mill, and the tailings impoundment. The tailings deliv-

Jan 8, 1986

By Paul C. Schmall, Lucian P. Spiteri, Arthur B. Corwin

Moving groundwater is generally recognized as the most adversarial condition for ground freezing. Moving groundwater can occur due to natural or man-induced groundwater flow, but either way may result in freeze formation difficulties. History has shown that if the condition goes undetected, catastrophic failure of the frozen shaft or excavation can occur. The success of ground freezing under potentially flowing groundwater conditions depends on an evaluation of the likelihood for this condition; an accurate and early diagnosis, with a careful evaluation of freeze pipe temperatures and piezometer water levels; and timely reaction to mitigate the possible delays. Successful remedial measures have included the reduction of ground permeability by modifying the soil properties between the freeze pipes with various kinds of grouting, or increasing the freezing effect by adding freeze pipes and/or the use of liquid nitrogen as the freezing agent.

Jan 1, 2007

By Clay Haynes

In 2005, Black & Veatch Corporation began designing a raw water conveyance system for San Luis Obispo County from Lake Nacimiento to the city of San Luis Obispo. The first element of the water transfer system will be a raw water pump station and lake tap. The wet well of the pump station will consist of a concrete lined shaft approximately 180 feet deep constructed in the very incompetent sandstone of the Vacqueros Formation. The lake will be wet tapped at approximately 172 feet below grade using a slurry earth pressure balance tunnel boring machine. The 48 to 72-inch finished diameter microtunnel will be approximately 500 feet in length. Construction is scheduled to begin in the winter of 2007.

Jan 1, 2008