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By William M. Dowall

The recently completed in-pit crushing and conveying project at Phelps Dodge's Morenci Mine is rated among the world's leading materials handling projects. The operation involves the crushing and transport of more than 109 kt/ d (120,000 stpd) of copper ore, using regenerative conveyors capable of providing more than 5.5 MW (7000 hp) of equivalent electrical energy. The Morenci Mine is located 330 km (200 miles) east of Phoenix, AZ. Phelps Dodge Corp. owns an 85% interest in the mine. The remaining 15% is owned by Sumitomo Metal Mining Co., Ltd. and Sumitomo Corp. Copper has been continuously produced from the Morenci district since the late 1800s. Until 1989, run-of-mine ore was transported from active mining faces to the Morenci and Metcalf concentrators by truck and rail haulage. In that year, a system of in-pit, semi-portable crushing plants and overland conveyors was commissioned. This substantially reduced truck haulage and effectively eliminated rail haulage in the pit. The system used two semi-portable, in-pit crushing stations equipped with 60/89 gyratory crushers. The crushed ore from both plants reported to the first of two overland belt conveyors, arranged in series, for transport from the pit to a coarse ore stockpile. The system was "backed-up" by existing locomotive rail haulage.

Jan 1, 1993

By Robert M. Matyas, P. E. Sperry, Robert J. Smith, A. A. Mathews

INTRODUCTION The first Dispute Review Board (DRB) was utilized on a tunnel project 20 years ago. Increasingly utilized on a wide range of construction projects, DRB's are becoming the norm on tunnel and underground projects. This paper summarizes the growth in this usage, uses observations and experience to establish that barriers to the utilization of DRB's are more perceived than real and that many arguments against the DRB concept are not valid, and notes some of the salient elements that should be considered in practice to optimize DRB effectiveness. The purpose of the paper is to provide an annotated checklist for current and prospective users. The basic concept, structure, and operation of DRB's are described elsewhere and will not be repeated here (ASCE, 1991). DISPUTE REVIEW BOARD USAGE A compilation of Dispute Review Board usage for tunnel and underground projects to January 1994 indicated use on 63 contracts with a cumulative construction value of $3.8 billion and a total of 60 disputes settled. As of that same date, DRB's were planned for another 63 contracts with an estimated construction value of $4.7 billion. (A listing of these 126 projects is available from the authors.) This success and popularity have spread to other civil projects as well as process and building construction. The increase in DRB usage has been exponential. See Figure 1.

Jan 1, 1995

By R. J. Lytle

INTRODUCTION Prior to excavation in soil and rock, it is useful to know the subsurface structure. This is important information both for safety and for equipment scheduling reasons. It is useful to know whether parts of the subsurface might be potentially troublesome or of different character than is generally thought present. By using geophysical probing, it is possible to infer the location and size of these unusual regions. The ground structure is commonly estimated from core samples taken from boreholes. These cores give a detailed knowledge of the structure in the borehole. However, knowledge of the structure exterior to the borehole can only be extrapolated from core data. By using seismic and electromagnetic cross-borehole geophysical probing, remote probing can be used to sense the region exterior to boreholes. A recent advance has significantly improved the state-of-the-art for defining the ground structure between boreholes. This new procedure utilizes large amounts of data and provides a detailed picture of the subsurface. The data processing algorithms used are similar to those in medical imaging of the human body using x-rays, a science called x-ray tomography. This imaging of the ground is called geotomography, which is a shortened acronym for geophysical tomography. Several examples of geotomography applied to imaging ground structure are presented. Our approach has been to probe the ground with electromagnetic and seismic waves. We map the region of interest with signals transmitted between multiple source and receiver pairs lowered in boreholes on opposite sides of the region (Figure 1). The received signals vary according to the transmission properties of the media

Jan 1, 1979

By Willard A. Murray

Investigations of underground coal gasification (UCG) have been actively pursued by the U.S. Department of Energy since the early 1970s; the Lawrence Livermore National Laboratory (LLNL) conducted its first field experiment in 1976. In conjunction with field and laboratory studies of the process of recovering energy in the form of combustible gases from the burning of coal deposits in situ, an extensive environmental program has been conducted at LLNL under the auspices of both the U.S Department of Energy and the U.S. Environmental Protection Agency. This program has focused on groundwater contamination and ground surface subsidence caused by UCG. The material presented in this paper is a summary of results from the environmental studies of UCG activities conducted by LLNL as described by Mead, et al. (1981) and supplemented by the author's experience with this program in 1980 and 1981. The following sections describe specific groundwater contamination and surf ace subsidence problems encountered during field experiments in northeastern Wyoming, and will discuss implications of preliminary findings from geohydrological investigations of a site in southwestern Washington. Finally, possible environmental control technologies that are most likely to be effective in mitigating environmental impacts are discussed.

Jan 1, 1982

By H. Lyn Bourne

This is the fifth annual tabulation of mineral royalty information. This tabulation, like the previous editions, includes all of the earlier data. There are also 60 new entries. In addition to royalty information, some entries show the cost of purchased reserves. Two articles relative to the evaluation of minerals reserves appeared in December, 1986. R.H. Paschall (In the Aggregate, ME, p 1139) wrote a good article, although it lacked specific royalty data. However, this author takes exception to two ideas in Paschall's column. Paschall contends that the royalty rate does not affect the mineral appraisal. This present author could not disagree more. Paschall also claims the location of an industrial mineral deposit is the only serious or practical caveat in comparing royalties. Comments received here from readers helped make the list of caveats that are cited each year. The readers will decide which factors influence the mineral value for their commodities of interest. Paschall's point about the relationship of the parties who are negotiating a royalty agreement is important and very well taken. The other article, written by William Vernon (Pit and Quarry, December 1986), gives a step-by-step process on how to conduct a mineral appraisal. The article cites three reasons for an appraisal: transfer rights; collateral for a loan; and taxation. A fourth reason is to establish adequate compensation for reserves lost through condemnation. This author has appeared in several court cases where compensation for loss of mineral reserves through condemnation required a mineral appraisal. Royalty rate becomes an important factor in the appraisal process, although the Pit and Quarry article refers to that part of the valuation equation as "profitability." Both articles were well written and are recommended reading for those interested in mineral valuations. The same caveats that have appeared in previous columns relative to factors that influence the value of reserves are restated. The data in the table serve as a general reference and are not intended to present an absolute scale of reserves costs. Several factors influence the value of any mineral commodity. The factors include: • location/transportation - especially significant for most industrial minerals; • market conditions both for the commodity and the company acquiring the right to mine; • quality or grade of the deposit as it reflects the amount of processing/beneficiation necessary to produce the finished product; and • legislative restrictions and conditions for mining a given material at a given site. These and other factors will significantly influence the cost of reserves. The table shows the range of royalties and the variations in the basis of computing the fees. In a few instances, it gives the cost of acquired reserves based on purchase price and quantitative estimates of the material in place. The table lists the commodity in column 1, and the subsequent columns give: • the location by state, US geographic area, or Canadian province ; • the cost - R for royalty and P for purchased cost; • the year in which the lease or purchase agreement occurred; and • comments or footnotes for more information. The cost column requires more explanation. The units may refer to cubic yards (/cu yd), cubic feet (/cu ft), short tons (/T), or acres (/A). 1 cu yd = 0.76 M2 1cuft = 0.28m3 1 st = 0.9072 t 1 acre - 0.4047 ha or m2

Jan 7, 1987

By John B. Sabey, Vernon R. Degner

The industrial coal processing trend toward greater fines production, due to mining techniques and customer requirements for reduced ash and sulphur content in the fine coal product, is the basis for ongoing efforts to improve the performance of the flotation machine. WCO has successfully adapted the principles of the beds Column to a full size machine prototype. Recent plant evaluation tests confirmed the initial promise of this concept by achieving a considerably lower ash product while maintaining the combustible recovery level of conventional flotation machinery. The paper will include a review of the fundamental principles of the beds Column concept, together with a summary of the WEMCO R&D Program from concept evaluation and laboratory testing, through pilot, to full size machine tests. The performance of the WEMCO/Leeds flotation column will be compared to conventional flotation concepts using a flotation "kinetics" approach, which quantifies the floatable and non-floatable specie recovery performance using the Klimpel model as the basis for analysis. The variety of distinct features unique to this concept include a series of barrier rods which are used to advantage, often together with countercurrent reflux water flow, to achieve a significant improvement in product grade. The hydrodynamics associated with the mechanics of "gangue stripping" from the rising "air bubble-floatable specie" matrix will be briefly reviewed.

Jan 1, 1988

By Christophe Bragard

The Los Angeles Metro Eastside Extension light rail project included a 1.5 mile underground segment, which consisted of twin 18'?10" ID tunnels, bored with two EPB-TBMs. One of the major project challenges after the completion of the bored tunnels was the excavation of six cross passages within alluvial geology below the water table and with low ground cover. Sequential excavation methods were employed and this paper details the design, ground treatment, support measures, and construction methods used to mine these cross passages beneath the congested urban streets of the City of Los Angeles.

Jan 1, 2008

By J. D. Morgan

In the first half of the year, lessening of cold war tensions was welcome. But Iraq's invasion of Kuwait in the second half led to the Persian Gulf War in January and February 1991. This caused an oil shock that dampened the economy. So the US gross national product rose only 0.9% to $5,463 billion (US billion = 109). The buildup of military forces in the Persian Gulf area focused greater attention not only on petroleum but also on other strategic materials. The Department of Defense continued to review stockpile goals and to upgrade several mineral materials. In addition, the Bureau of Mines continued to maintain the standby Emergency Minerals Administration. The Defense Production Act, which authorizes priorities, alloca¬tions and supply expansion, lapsed on Oct. 20. So the Selective Service Act of 1967 became the authority for assuring that orders of the armed forces and defense atomic-energy programs were given priority treatment. Consumer demand strongly affects mining worldwide. US citizens carry significant debt, and large stocks of housing and consumer goods are already in place. Some 250 million persons have 188 million licensed motor vehicles and 100 million dwelling units. Consequently, new car production fell 11 %, to 6.1 million units. Truck and bus production fell 8%, to 3.7 million units and new private housing starts fell 13% to 1.2 million units.

Jan 1, 1991

By J. G. Craig

This paper initially was to be on the design, construction and operation of the Lucky Friday mill. However, this subject has been pretty well covered in some of the mining publications in the past few years - specifically Mining Congress Journal for April, 1961 and Mining World for March, 1962- : In order to avoid too much repetition, we decided to present in this paper a comparison of the Lucky Friday mill constructed in 1959, and the Mayflower mill built by us in 1962. During the past three years Hecla Mining Company has constructed two relatively small mills: The Lucky Friday mill at Mullan, Idaho 750 T/day; and the Mayflower mill at Heber, Utah - 450 T/day. These mills were engineered, designed and constructed by Hecla, using principally our own personnel, with very little outside (contractor) labor employed. This paper presents a comparison of some of the interesting features of these mills, and where differences occur, it discusses the reasons for the various differences. It compares such points as the testing program, physical layout of the plant, construction costs, the grinding section, the flotation section, tailings disposal, metallurgy, recovery, grades, operating costs, etc. To help illustrate, and to compare these features, we will project pairs of slides showing each of the two mills. First a little background and history on the properties ---

Jan 1, 1964

By M. Slatter

The need for anti-corrosion coatings has existed for many years in the ground support industry, but the application requirements have made coating selection limited. Varying groundwater and chemical conditions continually challenge long term coating performance. Traditionally the industry coating preference has been hot-dip galvanizing due to its performance characteristics in highly corrosive environments and low cost nature. However, the galvanized coating has application limitations. This paper highlights some of these limitations and provides selection criteria for a new organic coating developed for one such difficult application, DSI?s Omega BoltPTM Pwhich is an expandable ground support. [ ]

Jan 1, 2009

By Larry H. Heflin

The Washington Metropolitan Area Transit Authority's Wheaton Station and tunnel design was completed and offered for bid in the Spring of 1983. The format was unique to the Authority: a four part, four fiscal year contract developed in response to funding limitations with construction divided into four stages allowing the maximum amount of work to be done each year for the funds available. The bid was based on the entire contract, but was orginally awarded for only the first year's work. Each year's work had a maximum funding limitation thus safe guarding the Authority from a grossly unbalanced bid. The Authority's estimate for this work was $83,871,524. The low bid came in at 61% of this for a total low bid of $51,512,058. The low bidder was ILBAU America Corporation whose home offices are in Austria. Following receipt of the bids (and resolution of objections cited by other bidders who felt that the job could not be done for the $51 Million dollar figure), a Notice-To-Proceed was given on October 5, 1983. The construction contract allows a Value Engineering Change Proposal, called a VECP which is initiated and developed by the contractor to change the drawings, specifications or other requirements of the contract. Among other things the VECP should decrease the contract price while maintaining the service life, reliability, ease of maintenance, and standardized features and appearance and not require an unacceptable extension of the contract time. A VECP must estimate the amount of the net savings

Jan 1, 1985

By A. Nieto

This article is a review of previous discussions about underground mining method selection and classification with the purpose to clearly define and classify the two groups of variables (indicators) involved in the mining selection process: key deposit indicators (KDIs) and key mining method indicators (KMIs). This paper provides a simple and clear approach for the classification and selection of a feasible underground mining method based on a predetermined set of favorable deposit characteristics, which are defined as key deposit indictors (KDIs). This article also gives a summary of the key advantages and disadvantages associated with every underground mining method based on their key mining indicators (KMIs). The selection method given in this paper is based on defining field KDIs and comparing them to the KDIs that are favorable to every considered mining method. By cross validating a matrix of favorable KDIs, the paper presents a simple approach to rank several underground mining methods using a scale from favorable to less favorable accordingly to the ore deposit characteristics (KDIs). KMIs are used to further complement KDI rankings by analyzing every method’s KMI performance based on the expected productivity of the mining operation being considered. To further assist the reader through the selection process, this paper gives basic sketches representing each of the primary underground mining methods discussed in this paper. Each method is given using the same 3D isometric view as spatial reference to assist the reader with visual interpretation and comparison between methods.

Jan 1, 2010

By Surendra Kumar Biswal, Sachida Nanda Sahu, B. C. Meikap

The unutilized iron ore fines (IOF, − 10 mm, 45% to < 60% Fe(T)) left at various mine sites during blasting and processing are rich in goethetic-hematite associated with high clay and considered a potential iron ore resource. The variation of loss on ignition (LOI) from mines to mines is based on the goethite and clay mineral content. The clay containing below 45 μm is mostly brittle, causing beneficiation problems. The IOF has an LOI of 7.83%, with high silica (5.52%) and alumina (4.57%), and 57.17% of Fe(T) subjected to both conventional deep beneficiation (CDB) and magnetization roasting using high-ash non-coking coal to adopt the suitable upgradation process. The CDB and magnetization roasting concentrate has 62.61% and 67.58% Fe(T) with 64.69% and 85.19% yield, respectively. However, the presence of 6.40% LOI in CDB makes the ore challenging for pelletization. Characterization like X-ray diffraction(XRD), scanning electron microscope(SEM), and chemical analysis was used to assess the concentrate quality and potential industrial application.

Jun 4, 2022

By Carl G. Bock

INTRODUCTION The Washington Metropolitan Area Transit Authority (WMATA) has let a contract for the excavation of three rock stations, spaced about 3550&apos; (1082m) apart, beneath Connecticut Avenue in Washington, D.C. Two previous rock stations have been completed, one of which had a crown pilot tunnel excavated to explore geologic conditions that would be encountered during the station excavation. This pilot tunnel was primarily for inspection by bidders and design was based on core hole information. The other rock station had no pilot tunnel and was also designed on the basis of core hole information. The three rock station areas, which are the subject of this paper, have been explored by crown pilot tunnels and an as-built report, with geologic maps and sections, has been prepared, for use by the design engineer as the basis of design for support of the structures. The geotechnical report describes the geologic structure in detail and relates it to excavation and support of the three crown pilot tunnels and the running tunnels which will be enlarged to create the 58&apos;W x 44&apos;H x 700&apos;(+)L (17.6m x 13.3m x 212m +) stations. The information was complete enough to permit the design engineer to visualize the geologic structure and compute loads for the various types of rock conditions. It was therefore possible to determine the size and spacing of the steel sets for the several different conditions of rock structure encountered in the pilot tunnels.

Jan 1, 1976

By M. A. Trevits

The National Institute for Occupational Safety and Health (NIOSH), in partnership with the Mine Safety and Health Administration (MSHA), is conducting research to test, evaluate, improve or modify coal mine fire-fighting strategies and methodologies through large-scale tests. Since wood is the second most abundant fuel available during a coal mine fire, it was decided that series of large-scale wood crib fire tests were needed to measure the products of combustion and to observe the capability of commonly available direct application fire suppression equipment, namely, fire extinguishers, water and gas-enhanced foam. This paper discusses the wood crib fire tests, provides insight into the products of combustion and describes observations made during the application of the fire suppression agents.

Jan 1, 2009

By W. J. D. Stone

In 1960, Magnetics International Ltd. undertook the development of the Jones High Intensity Wet Magnetic Separator in the Americas. Magnetics International had a number of possible applications in its own projects plus the intention of developing the equipment for sale to others. It was soon recognized that no matter how innovative a piece of mineral separation equipment may be, it takes many years and much finance before it is finally accepted for large scale use. For this reason, many good ideas die in their infancy. One of the chief reasons for such a time lag between conception and large scale implementation is the usual lack of finance to construct and put into operation a large demonstration unit. Even with a large unit for demonstration, the first major user usually requires a guarantee that is not normal in accepted separation equipment. Such problems are also normally accompanied by major design changes from the first conception.

Jan 1, 1971

By Bradford F. Townsend

A study was made on six collapses that occurred during large-diameter tunnelling through weak sedimentary rocks and soil using SES methods in three stages?top heading, bench and invert. The collapsed lengths are between 20 m and 277 m. The collapses were re-mined using essentially the same tunnel-ling method with larger excavation profiles to accommodate the designed remedial measures consisting of ground treatment, pre-support and stronger initial support/outer lining required to carry higher ground loads acting in the collapsed lengths. The paper presents information on the collapses and the design and execution of the remedial measures.

Jan 1, 2008

By W. J. Schlitt

The development of forced aeration as an approach to enhancing copper sulfide leaching is traced from its earliest development up to present day operations using this technology. Both large-scale field tests and commercial operations are covered. The historical portion is preceded by an introductory discussion of the role of air (oxygen) in sulfide leaching. Sufficient aeration may be achieved via naturally induced convective airflow. However, cases are identified where this is insufficient, leading to retardation of the sulfide leach rate. For these situations, forced aeration may be beneficial. The historical portion of the paper focuses on the major field tests that have been conducted in Montana, Nevada and Utah, along with commercial operations in the United States, Australia, Chile and Peru. The paper concludes with some general comments about the applicability of forced aeration, which are based on the information developed to-date.

Jan 1, 2006

By W. H. Schiffbauer

The protection of miners, equipment, and infrastructure is discussed. While the primary focus of the described technology is to prevent miners from being injured, struck-by, or crushed by heavy equipment; another major benefit realized is also the protection of equipment and infrastructure. An attempt is made to define and classify the systems used to provide proximity detection and warnings as well as collision detection and avoidance. Information about the speed of vehicles and human operator response time can be a factor in the choice of what type of system and what features are needed to properly address the needs. How the technology adjusts to compensate for various vehicle speeds, while maintaining the same level of protection is noted. The statistics which justify the need of miner protection are provided. The primary system components required, what attributes they feature, and how they respond in the environment, is briefly highlighted. The physics behind the danger zone marker technology and what makes it so robust and reliable is established. Examples of a few mining applications and specific operational modes are provided for both surface and underground.

Jan 1, 2011

By Robert M. Valentine, Randall L. Lentell

Interpretive geotechnical investigations were performed for the construction of approximately 15,250 m (50,000 ft) of wastewater interceptor tunnels in Austin, Texas. Subsurface materials consist of claystone (or clay shale), siltstone, altered volcanic tuffs, chalk and limestone. Special conditions include multiple crossings of Onion Creek with cover ranging from about 1/2 to 3 m (2 to 10 ft.), and the potential for mixed-face conditions consisting of water-bearing gravels overlying clay shale or siltstone. The methods and results of the geotechnical investigations are discussed and the inferred construction conditions are compared to those encountered during tunneling. A suggested format is presented for interpretive geotechnical reports for underground construction projects.

Jan 1, 1985