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By Gary Brieley

Until well into the 20th century, most construction work was performed under the auspices of a master builder or in a manner that would be described today as design-build. In addition, many civil engineers served as ?interns? under the tutelage of a master builder in order to learn how to design and construct a certain type of structure. This was certainly the case for tunneling projects with various individuals having been identified as tunneling experts as a result of successfully completed projects The master builder approach began to change in the early 1900s to a model that would be referred to today as design-bid-build. A design-bid-build approach to project procurement gives the owner more control over the final product and al-lows the contractor to know exactly what is expected of them before the work is constructed. As a result of this transition in project procurement, civil engineering schools placed a greater emphasis on the training of ?design? professionals. This article will document how the training of tunnel design professionals progressed within the United States. Although it is difficult to generalize about the hundreds of tunnels that were constructed in the first four decades of the 20th century, there is one project that stands out as having resulted in a university program related directly to tunneling and that is the Chicago Subway. During a visit to the United States in 1938, Dr. Karl Terzaghi met a student named Ralph Peck who was then studying at Harvard University in a pro-gram established by Arthur Casagrande. Shortly thereafter, Terzaghi traveled to Chicago for a lecture and was asked to consult on the Chicago subway project that was then under construction. The Chicago subway was being constructed in clay, and the owners were worried about possible settlements to nearby buildings. Terzaghi asked Peck to serve as his field engineer for that project. Thus was established one of the most productive relationships in the history of civil engineering in the United States. Peck, who would become Dr. Peck, moved to Chicago in 1939 to participate in an extensive research project that con-tinued until subway construction was halted in 1941 because of World War II. During that time, the cost of subway construction in Chicago was reduced substantially as a result of Peck?s observations and Terzaghi?s recommendations. In fact, it was reported that subway construction in Chicago cost less than one-half of similar projects in London even though the clay in London is considerably stiffer compared to Chicago. Upon the completion of his work on the Chicago Subway, Peck accepted a professorship with the University of Illinois in Champaign/Urbana.

Jun 1, 2010

By Firoze E. Katrak, John R. H. Black, Paul R. Ammann, Michael J. Loreth, Servi. Italo S.

Germanium is produced primarily as a by product from zinc concentrates. The important sources of gallium are alumina ores (bauxites) and zinc concentrates and residues from zinc processing. In addition, gallium as well as germanium may soon be recovered from a depleted copper mine near St. George, Utah. The major uses for germanium are in semiconductors, lenses in infrared optical systems, catalysts, and gamma radiation detectors. The major markets for gallium are in light-emitting diodes, solar cells, laser diodes, integrated circuits, microwave devices, and magnetic bubble memories. CRA projects a healthy growth in the demand for both metals. However, the role of scrap metal will continue to be important over the next decade, thus decreasing the overall demand for primary gallium and primary germanium. This paper summarizes the key elements and the economics of the markets for germanium and gallium. Much of the information, such as plant-by-plant costs of production and estimates of consumption by end use for various countries is from proprietary databases of Charles River Associates.

Jan 1, 1986

By Danqing Gao, Brijes Mishra

Heterogeneity in rock formation affects both rock behavior and strength. Spatial variance of rock properties is an important characteristic of rock that addresses the heterogeneity of mechanical and physical properties and their effects on underground mining. Assessing spatial variance can be useful for locating potential difficult grounds and for performing reliability analysis in the mining support system. This study presents a spatially correlated, random model to investigate the influence of rock heterogeneity on rock strength and failure propagation. A random field database with specific spatial correlation was created for each physical-mechanical property using laboratory data and the extreme value stochastic model in MATLAB. Based on the improved microscale random model, we considered one three-dimensional numerical model to study a mine operating in the Pittsburgh seam. The influence of random field data on entry roof was investigated. The realistic random field database added two scale-measured parameters from horizontal and vertical directions to control the spatial correlation length. A number of cutting sequences were also considered in order to identify the effect of spatial variance on roof behavior. The results show that spatial variance provides an accurate prediction of erratic roof falls in coal mines.

By J. J. Gusek

The Riley Pass strip mine is an abandoned uranium-bearing lignite deposit in Harding County, South Dakota, covering about 150 acres of highwalls, pit floor and mine spoils exhibiting elevated levels of radioactivity. Six reclamation design alternatives were developed, ranging from doing nothing to reclaiming to approximate original con-tour. The alternatives were evaluated for expense, site stabilization, and mitigation of public safety hazards. A comparative economic evaluation on three of the alternatives was completed for the Forest Service in selecting an alternative and substantiating federal funding requests. This evaluation included economic impacts associated with physical and radiologic health hazards, affects on recreational users, socioeconomic impacts and environmental improvement.

Jan 1, 1995

By Ch. R. V. S. Nagesh, Ramesh Naidu Mandapati, Venkata Swamy Nalajala, Tondepu Subbaiah, Naga Jyothi Kothamasu

Leaching studies of magnesite obtained from Tamilnadu Magnesite Limited, Salem, have been carried out using hydrochloric acid leaching and percentage of magnesium chloride recovered was estimated. The variables considered in this study were the following: duration of leaching, volume percentage of hydrochloric acid, temperature, and pulp density. Percentage recovery of magnesium chloride increased with duration of the leaching, volume % of concentrated hydrochloric acid, and temperature. Percentage recovery of magnesium chloride decreased with increase of pulp density. The optimum conditions found to be pulp density (10%), hydrochloric acid concentration (30%), duration of leaching (2 h), and temperature (348.15 K). Iron was removed by treating the leach liquor with hydrogen peroxide and by raising the pH to 3.5–4. The purified leach liquor was subjected to spray drying for producing high pure magnesium chloride.

Jun 7, 2022

By Lukas Erkurt, Wolfgang Holzer, Stefan Auderer, Richard Gradnik

SEM/ NATM Tunnelling contracts in Austria and Germany are usually tendered applying unit price contracts. The purpose of this paper is to show how contractual problems are resolved in these countries. The focus will be put on describing the theoretical approach, several case studies will show how contractual problems were dealt with on site.

Jun 23, 2024

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 A. H. Brisse

In considering the use of a coal or a coal blend for the production of metallurgical coke, the fact is often overlooked that laboratory data can be most effectively used to determine coke plant operating conditions conducive to maximum output as well as to predict the quality of coke produced. The discussion here presented attempts to point out the manner in which carbonization data can be interpreted for industrial use and the significance of specific laboratory test results in this interpretation. The major considerable must, of course, be the safeguarded of coke oven batteries, against wall damage arising either from excessive carbonization pressures or from the wedging of the pushing ram into non-contracting coke charges. In order to be specific in the matter of handling the laboratory data involved, two series of blends are analyzed. The first of these, referred to as the "AB" series, is typical of some d' the more highly expanding Eastern- coal blends whereas the second series, here referred to as the "CD" series, is probably more typical of the Western coal blonds. Reference to Table II should be made for rank of coals considered in these blends.

Jan 1, 1959

By John Newby, Mahmood Khwaja, Bernard Theron, Janice McGovern, Bernard Catalano, Michael S. Schultz

Launching a full-size pressurized-face Tunnel Boring Machine (TBM) in difficult ground conditions is always challenging. Recently, few projects have innovated the process by scaling the trenchless method of pipe jacking, and modified steel bell approach, to facilitate the launching of a full-size TBM without the need for large and deep trenches, starter/tail tunnels, or for incrementally installing supporting gear as the machine advances. This paper presents three such projects; evaluates the post-bid contractor proposed modifications; details the innovative use of pre-cast pipe segments to facilitate machine launch; and, provides an overall assessment of the benefits, challenges and lessons learned related to the modified approach.

Jun 13, 2021

By Harry R. Asche, Manfred K. Lechner

The Cross City Tunnel comprises 2km of a new underground traffic route in Sydney, Australia. The route is very complex, involving some six separate tunnels and three underground Y-junctions. For almost 200m the six tunnels run parallel at different level sunder William Street, Sydney. Almost all of the route runs adjacent to the City Business District of Sydney and adjacent to or below many major buildings and services. The planning and design of this project is described. The geometric arrangement is achieved with a strong dependence on 3D road design packages. Road alignment constraints include land acquisition and proximity to existing tunnels and basements as well as maintaining separation from the other tunnels in the scheme. Geotechnical and hydrogeological studies are described. Findings discussed include the high horizontal stress field in the Sydney area and investigation of incised palaeochannels on the route. Methods of design for the tunnels and Y-junctions are described, as well as methods of settlement prediction for the buildings and services. The latter includes the settlement assessment for more than 200 buildings, many in excess of 20 storeys, as well as services including all of the city railway lines in Sydney.

Jan 1, 2003

By Daniel Maine

Swelling clay soils have been problematic to many types of infrastructure in the United States. However, their impact on underground construction is often misunderstood. The use of swell pressures in design of initial tunnel and shaft support lacks proper guidance and is often mis-interpreted. This paper provides insight and guidance on how to implement a geotechnical investigation program to determine if swelling soil exists at a site and how it impacts the design of temporary support systems for underground projects. An example is provided for how swell pressures were incorporated into the design of an initial support system for a rib and lagging tunnel system and problems that occurred.

Jun 23, 2024

By Jun Han

Coal has been mined in the Kailuan mining area for more than 130 years. The remaining reserves consist of, in large part, coals that would have been considered economically unminable or technically not feasible by the previous generations. Some of the current operations have to resort to overmining because the lower seams had been extracted in the past. This paper deals with the feasibility and proper layout of mining roadways of overmining carried out in the No. 5 seam of Qianjiaying coal mine of Kailuan mining area using numerical and physical simulation. FLAC2D was used to investigate the characteristics of stress and displacement in the overburden after extraction of the lower seams. It also analyzed the proper layouts of gateroads in the upper seams, i.e. locating them in the stress-relief zone of the gob so that their stability can be easily maintained. In addition, a two-dimensional physical model was constructed for investigation of damages to the upper seams due to mining of the lower seams. Finally, based on the results of investigations, proper gateroads layout was designed and successful extraction was implemented for panel 1357 in the No.5 seam.

Jan 1, 2009

By William D. Hanson

Celestine (celestite) (SrSO4), the primary ore mineral of strontium, is present in the DeQueen Limestone Member of the Trinity Group (Lower Cretaceous) in Sevier, Howard, and Pike Counties, southwest Arkansas. Two mappable celestine beds have been identified. One bed is commonly 3-5 in. thick, but ranges up to 18 in. in thickness; the other bed is generally 2-3 in. thick. The beds are concordant within the DeQueen Limestone and were formed by precipitation from periodically restricted sea water. Reports concerning celestine date back to 1929, when Hugh D. Miser and A. H. Purdue mapped the geology of the DeQueen and Caddo Gap quadrangles. A small amount of celestine was produced in the early 1940s in Howard County. During 1941, the J. W. Hintze Company collected 1,500 pounds of celestine for testing purposes. In 1942 and 1943,750 test holes were drilled by the Bennett-Clark Company in Howard County. Afterward, approximately 90 tons of celestine was open-pit mined and shipped to Texas for processing. Since then, no mining of celestine in Arkansas has taken place.

Jan 1, 1999

By L. R. Stoiser

The mineral resource potential of the Los Bronces deposit was successfully evaluated by an intense, coordinated field program over a 37-month period (April 1978 - May 1981). This project was part of a much larger study to determine the economic feasibility of expanding the open-pit, mine-mill operation 10-fold to 80 kt/d (88,000 stpd). The resource project included more than 120 km (74 miles) of core drilling and 64 km (40 miles) of drill rig access way construction under adverse topographic and climatic conditions, detailed geological mapping, and other related activities. The Los Bronces deposit is composed of an earlier mineralized porphyry-type body intruded in part by a large complex of mineralized hydrothermal breccia pipes. The mineralization is hosted by intrusive and extrusive igneous rocks. Various stages of erosion, oxidation, leaching, and supergene enrichment of copper are present. Drill hole indicated geologic reserves are estimated at 1.3 Gt (1.4 billion st), averaging 0.81% copper and 0.016% molybdenum at a cutoff grade of 0.6% copper equivalence decreasing to 0.25% over the life of the mine. Trace amounts of silver are also present.

Jan 1, 1987

By Brian Young, Ben Pantony

Interferometric Synthetic Aperture Radar (InSAR) has played an integral role in many large scale tunneling projects globally. Until recently, it has been regarded as a complementary monitoring tool. On the Los Angeles Metro Purple Line Phase 1, InSAR was proposed as a primary means to replace weekly and bi-weekly surface monitoring requirements on surrounding critical infrastructure. This paper will summarize the statistical analysis approach engaged in order to compare and contrast a year of historical InSAR data to known geodetic survey data, in order to utilize InSAR as an operational monitoring tool on this project.

Jun 13, 2021

By Yixian Zhao

Although many ultimate pit limit design algorithms have been developed for the past one- quarter century, only the well known Lerchs-Grossmann's (LG) algorithm is capable of producing a truly optimum ultimate pit limit today. This paper presents a graph theory oriented algorithm for optimum ultimate pit limit design. This algorithm produces a true optimal solution and maximizes the total undiscounted net profit for a given 3-D block mine model. The algorithm performs much better than the well known LG algorithm, in terms of the reduction in computation time and computer memory requirements. More importantly the new algorithm is easier to understand and implement than the LG algorithm. Specifically, this paper discusses: 1) the computer representation of arcs and the rules of arc generations which dictate the formation of trees in the graph, 2) the mechanism of joint support and re-allocation, 3) the properties, the general procedures of the algorithm, and the suggested specific steps to implement the algorithm, 4) comparison between the new algorithm with LG algorithm, and 5) some experience in implementation of the algorithm and two case study results.

Jan 1, 1992

By A. L. DeVegt, H. G. Bayer, C. J. Buisman

During the last ten years, Paques Inc. has been engaged in the development and installation of treatment systems to remove sulfur compounds from water and gaseous streams using biotechnological processes. Metal and sulfate can be removed from mine waters in two biological steps. In the first step, sulfate-reducing bacteria converts sulfate to hydrogen sulfide (H2S). The HS reacts with the dissolved metals to form insoluble metal sulfide precipitates. In the second step, sulfide-oxidizing bacteria convert excess H2S to elemental sulfur. The Budelco Zinc Refinery in The Netherlands installed a groundwater treatment system to remove metals and sulfate using the biological steps described above. The system has been operating since May 1992 and has been treating 5,000 m3/d (180 thousand cu ft/day). A pilot plant began operation in November 1995 at Kennecott's Bingham Canyon Utah copper mine to develop processes for metal and sulfate removal from groundwater and for the selective copper recovery from leach water. The principle of the biotechnological methods, the full-scale experience and an overview of the test program at the mine are presented

Jan 1, 1999

By H. Huang, J. C. Wu, C. H. Xie, Y. Q. Xue, Z. H. Zhang

Two- and three-dimensional groundwater flow models for dewatering in an opencast mine are presented. The models focus on solving special problems using numerical simulations of the opencast mine. These special problems include the drying up of the aquifer, the movement of the model boundary and the prediction of the residual head. These models are used to describe the decline of groumdwater levels in the Yuanbaoshan Opencast Coal Mine and its neighboring area during the drainage period. The simulated values agree very well with the field data. There have been several successful examples of numerical simulation for predicting the mine dewatering rate in an opencast mine. However, The hydrogeological conditions for the Yuanbaoshan Opencast Coal Mine are rather complex, and the total average flow rate is very high at 4.676 x 105 m3/d (1.65 x 107 cu ft/day). In this paper, a two-dimensional groundwater flow model in a large area is developed to solve the problems mentioned above by simulating regional drawdowns of the groundwater level during the drainage period, and a three-dimensional flow model is developed to simulate the residual head near the open-pit bench.

Jan 1, 1998

By Robin J. Batterham, Stephen H. Algie

It is often stated that innovation is central to the economic survival of mining and mineral processing in the face of global competition, and yet technology is often far from a core strategy in our industry - hence the concerns that are often voiced about the apparent slow rate at which new technology is applied. Much of the discussion stems from a lack of understanding of the role of technology in innovation, and of the role of R&D within the innovation process. To a large extent this has all been said, however, the messages are clear and deserve repetition. This paper expresses the personal views of the authors, based on experience in government-funded (CSIRO and universities) research, and in CRA Ltd, a large mining and mineral processing company. Further than this, it explains how our own development unit within the CRA Group has come to see its key roles as including the transfer of technology, and the training of technologists to move into the operating business units. We conclude that these critical tasks are the keys to creating the environment that will allow us to maximise the contribution of technology.

Jan 1, 1995

By C. J. Newman

Prior to 1995, the smelting process at the Kennecott Utah Copper Corporation (KUCC) smelter consisted of Noranda reactors and Pierce-Smith converters. In the consideration of expansion opportunities, the existing process did not lend itself to a program geared towards processing the total output of KUCC mining and milling operations. During 1989 and 1990, a number of smelting options were evaluated. The final selection was the Outokumpu flash smelting process, coupled with the new Kennecott-Outokumpu flash converting technology. Facilities were designed and installed to process 1.0 million tonnes per year of copper concentrate, with the ability to expand to 1.2 million tonnes per year. Following the shutdown of the smelter facility utilizing the Noranda technology in May 1995, the flash smelting furnace commenced operation in June with the flash converting furnace startup following a few weeks later. The smelter has achieved design production targets and environmental goals. Current operating rates are at or above design rates for concentrate and matte processing. Emissions are lower than the permit levels and equate to less than 3.5 kg of S02 per tonne of copper. This paper outlines the design, construction, startup and the first two years of operation of the modernized KUCC smelter.

Jan 1, 1998