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By F. Rudloff, C. Karageorgos, J. Moyo, I. Boadi, M. Struble, B. Lumsden

Over it’s more than 100-year history, the Kennecott operation has often been at the forefront of innovation; driven by the demands of the lower grade ore-body and the higher costs of operating in the US where wages are generally higher and regulation more restrictive. One way of reducing operating costs in c/lb is to increase the lbs produced at minimal cost. Despite the relatively coarse grind at Kennecott - about 30% >150μm, approximately 20% of the Cu lost to tail is liberated chalcopyrite in the <20μm fraction, and about 30%-40% in the <37μm fraction. In 2020 Kennecott undertook a detailed plant scale test of the magnetic aggregation technology to increase copper recovery by reducing fine copper losses. A paired statistical plant test of magnetic conditioning on one rougher line showed a 1.12% increase in Cu recovery to 97% statistical confidence. The next challenge, unforeseen at the start of the project, was the fabrication and transportation to site of the equipment for the three remaining rougher rows, during the severe supply-chain constraints of the Covid pandemic in 2021. This resulted in delays and unforeseen costs as world-wide transportation became chaotic, particularly transportation via west coast USA. Nevertheless, the project was completed and commissioned, with only minor delays and cost increases, due to a flexible approach to overcoming the hurdles encountered.

Feb 1, 2023

By George L. Atwood

The western phosphate field, one of the United States&apos; great mineral resources, lies within the western states of Idaho, Utah, Wyoming and Montana. This Permian sedimentary deposit has been known since the turn of the century and since the 1920&apos;s has been mined for its phosphate content. Isolation from markets and relatively high mining costs have restricted development as compared to eastern United States deposits, but nevertheless a significant western phosphate industry has developed. Geographically the deposit covers an enormous area of about 337 000 km2 (130 000 sq miles). It covers Idaho from Pocatello east- ward, western Wyoming to the eastern flank of the Wind River mountains, and extends well into southwestern Montana and into a large area of northeastern Utah north of the Uinta Basin and east of the Salt Lake valley.

Jan 1, 1983

By Ali Hafiz, Aidin Golrokh, Tom Iseley, Kaz Tabrizi, Saleh Behbahani

In the USA many highway tunnels were built during the 1930s through 1960s. This indicates that these tunnels have exceeded their intended design service life. Based on the initial tunnel inventory conducted jointly by the Federal Highway Administration (FHWA) and the Federal Transit Administration (FTA), more than 526 highway tunnels have been identified in the USA. For understanding the condition of the tunnels and risks associated with deteriorating conditions, comprehensive condition assessments are necessary to mitigate risk and remediate works as required. Monitoring the condition and rate of deterioration of tunnels is vital for timely tunnel maintenance and rehabilitation to avoid sudden tunnel collapse. This session will explain the necessary steps for tunnel inspection and review some of the state of the practice information on tunnel inspection techniques.

Jun 13, 2023

By R. K. Singhal

In 1990, Canada produced 69.4 million tonnes of coal of which some 65 million tonnes was produced by surface mining methods. The two Western Canadian provinces, Alberta and British Columbia produce approximately 55 million tonnes of coal by surface mining. These two provinces also provide the bulk of the metallurgical coal for export. The geological conditions in the Western provinces particularly in the mountain region are complex. The coals are friable and the seams are steeply inclined, sheared, intensely folded and faulted. There may be as many as 15 to 20 coal seams present with true thickness ranging from 2.5m to over 8m. Most of the Canadian surface mines are large (over one million tonnes per annum) using modern mining equipment such as shovels, high capacity trucks and draglines. At present the industry is going through another of its up and down cycles but has continued to make impressive gains in productivity. This has been achieved through greater mechanization, better management practices and a will to succeed in a highly competitive world market. This paper presents an insight into the current status of the Canadian Coal Industry and essentially updates the information given by the authors at previous SME meetings.

Jan 1, 1992

The Penetrating Cone Fracture (PCF) technology 1 is a new method of rock excavation developed by Sunburst Excavation, Inc. of Denver, Colorado. PCF is a rock excavation method which employs tensile breakage mechanisms under controlled conditions to enable the continuous excavation of rock?in underground and some surface applications. The technology has developed rapidly over the last two years to the point where it is now being prepared for commercial application in the mining and civil construction industries. The initial commercial application of PCF will be undertaken at the Perseverance Nickel Mine of Western Mining Corporation Limited in Western Australia beginning in May, 1994.

Jan 1, 1994

By Kevin DeSomber, Scott Bird

Larger grinding mills continue to utilize large gear-driven drives or electrical wraparound drives. The panel will include presenters from operations with large mechanical and electrical drives. JIM HANDLEY: Before we get to the third and final session, I want to introduce my co-conspirator for this session, John Mansanti. John is manager of milling with Newrnont Gold Company, Carlin, Nevada, and was very active in securing participation in this innovative symposium. I&apos;m Jim Handley and I&apos;m with Cyprus-Amax Minerals at the Sierrita copper and molybdenum mine. Our third presentation is titled "Geared Up or Wrapped Up?" I hear this topic discussed, but never at great length. I think that&apos;s because the opinions are fairly strong and diverse, and people generally aren&apos;t reinforced properly in their arguments. The first person to enlighten us on this topic is Scott Bird. He has more than 20 years with Kennecott, is a graduate in metallurgical engineering from the University of Utah, and is currently operations superintendent and deals with this phenomenon every day.

Jan 1, 1998

By J. F. Stenebråten, W. P. Johnson

Carbonaceous material (CM) from the Barrick Goldstrike Mines, NV, was characterized with respect to its gold sorption (preg-robbing) and gold recovery behavior. The breadth of graphite peaks measured by X-ray diffraction were used to calculate crystallite dimensions (002) of the CM. The (002) dimension was found to vary inversely with preg-robbing activity and directly with gold-recovery behavior, indicating that the degree of graphitization (maturation) experienced by the carbonaceous material is correlated with gold-loss during ore processing. The inverse correlation of preg-robbing activity was improved when percent preg-robbing was regressed against (002) crystallite size and carbon content. The (101) crystallite dimensions of all samples were calculated from laser Raman analysis, and were not found to correlate with preg-robbing behavior of the CM. BET surface area and micropore size distribution results were affected by grinding history, negating comparison of these characteristics between samples.

Jan 1, 2000

By Andy Ingriselli, Andrew Famiglietti, John Westland, Greg Landry

Atlas Dewatering was contracted to install and maintain a groundwater control system for the new Bessarion Subway Station and the Tail Track Structure on the Toronto Transit Commission’s new Sheppard Subway Line. Atlas met the challenges presented by the project by closely reviewing the contract documentation provided by the Program Geotechnical Consultant, Golder Associates and by working with the general contractors, Bondfield Construction Company and PCL Constructors Eastern, inc., throughout the duration of both projects. In addition to concerns about soil loss, excessive settlement and seepage, the consultant was concerned about spreading hydrocarbon-contaminated groundwater between the two aquifers present at the Bessarion Station site. By installing a system of multi-level vacuum eductor wells around the perimeter of the excavation, Atlas was not only able to provide a dry excavation for construction, but, due to a unique well design was also able to prevent cross-contamination of the aquifers.

Jan 1, 2001

By Angus Campbell, Michael J. Gobla

Numerous techniques for treating, controlling, and preventing acid rock drainage have been applied at the Summitville Mine Superfund Site. Challenging aspects of the remote mine site include the wide-spread occurrence of acid-generating soils and rocks, extensive surface and underground mine workings, and a cold and wet climate. Water treatment was an immediate necessity when the Government took control of the abandoned site in December of 1992. Subsequent reclamation activities have emphasized prevention and control of ARD to minimize future water treatment requirements. A combination of conventional, innovative, and experimental methods are being applied to successfully mitigate ARD at Summitville.

Jan 1, 2000

By Drummond Earley III

The U.S. Bureau of Mines is currently conducting laboratory experiments to study the reactions occurring during in situ leaching of oxide copper ores hosted by biotite-poor granite and biotite-rich granite porphyry. Detailed pre-leach and post-leach petrographic examinations of the rock samples are combined with the leach solution chemistry resulting from core leaching experiments to enable an evaluation of the various reactions which are responsible for the observed fluid chemistry. The information resulting from these laboratory studies is being utilized to support the design of the Bureau&apos;s ongoing field research project at the Santa Cruz deposit near Casa Grande, AZ. Atacamite and chrysocolla are the primary copper minerals present in this deposit, and both are readily soluble in the dilute 5% sulfuric acid solutions used in these experiments. In addition to the dissolution of copper minerals, biotite dissolution also occurs during the experiments, contributing K, Mg, Fe, and Al to the leach solution. The biotite dissolution appears to be non-stoichiometric, as it is progressively altered to vermiculite and finally, amorphous silica. While K, Mg, and Fe concentrations in solution steadily increase with time, Al quickly reaches a maximum, and then remains relatively constant for the remainder of the experiment. This suggests that Al saturation is achieved, and this Is supported by the presence of precipitated Al sulfate and aluminosillcate clay mineralization in the post-leach rock samples.

Jan 1, 1990

By R. J. Pugh

In addition to directly analyzing the surfaces of minerals using high vacuum instrumentation methods, some important surface properties of mineral fillers can be determined indirectly by using reactive chemical probe molecules. This technique enables the strength and the number of the surface reactive sites to evaluation and this type of information is useful in predicting interfacial behaviour of minerals. One method of classifying these surface sites is by using Lewis acid/base theory and this type of approach could enable one to predict the adsorption of functional groups in dispersants, thickeners, pigments, etc. Also the adhesion of polymer matrices to the filler surface may be improved.

Jan 1, 1992

By J. B. Offei, K. Awuah-Offei

Mining companies registered with the SEC were required to comply with Regulation S-K 1300 for their annual report covering the first fiscal year ending on or after January 1, 2021. Consequently, most mining registrants filed their first S-K 1300 compliant disclosures in 2022. The US Securities & Exchange Commission (SEC), as part of its disclosure review program, has been issuing comment letters in response to these filings. This paper presents an overview of the trends in these comment letters. The authors reviewed comment letters retrieved from the SEC’s EDGAR database based on Standard Industrial Classification (SIC) Codes that cover mining, the content of the comment letter (whether it references S-K 1300 or not), the names of SEC staff listed in the comment letters, and other criteria. The analysis shows the SEC staff's reviews have been comprehensive covering the breadth of S-K 1300 and eliciting compliance with the rule. The staff through their comments are eliciting all the disclosures required by S-K 1300 and are not allowing registrants to substitute disclosures based on other standards for S-K 1300 disclosures. It is important, however, not to over generalize as the comments are based on the particular context.

Feb 1, 2023

By Richard L. Gordon, William A. Vogely

ENERGY POI.ICY-PRINCIPLES AND THEIR PRACTICE Persistently, at least since the end of World War 11, governments have intervened broadly, deeply, and incoherently in major energy markets. If we take a broad definition of energy that encompasses gas distribution and electric power, we can observe regulations of even older vintage. This trend, of course, is not unique to energy. Expansion of government controls has occurred in many areas. The relevant basic question about energy regulation, therefore, is not why is energy special, but whether any general principles exist to explain the wisdom of existing regulations. This review takes place at a time, the middle 1980s, in which a massive onslaught is being undertaken against government regulation. However, the present chapter is influenced primarily by my observations of the failures of energy regulations and not by any inspiration from those ideologically opposed to government intervention. Several subquestions arise in policy appraisal. A primary need is to establish clear objectives and determine the consistency between these goals and the policies imposed. Thus, the first step is to set objectives. The next is to outline ways to attain these goals. However, it should be recognized that many apparently distinct options are economically equivalent. When the goal is to charge producers or consumers for something, it is possible to attain the same result through either government ownership or taxing private transactions. The tax can raise the price to the level the government would have charged if it were the owner. Creation of a Department of Energy is not necessarily any different from having separate energy agencies well coordinated by some small supervisory body. Thus, a distinction should be made between substance and form in policymaking. The critical substance concerns such matters as whether the government imposes financial penalties, incentives, or rules to attain a goal. Then, there can be many equivalent ways to implement the basic policy form. The second prior illustration suggests that one favorite question is how to attain proper integration of policy. At various times, voices on either (or even both) sides of the Atlantic have called for a coordinated energy policy. The U.S. Paley Commission made this a primary goal for future policy. The western European governments that were the founding members of the Coal and Steel, Economic, and Atomic Energy Communities spent much time in the middle fifties and much of the sixties trying futilely to agree on an energy policy. (See Gordon, 1970 for an annotated review). The energy price rises of the 1970s rekindled United States interest in coordination. However, astute observers of the problem such as O. C. Herfindahl of the United States and Maurice Allais (1 962) in France warned the discussions confused form with substance. The crucial issues were what were the goals and what were the best types of policies to attain such goals. Policy suffered, not from poor organization, but from discord about the goals and how to attain them. All this suggests that we need principles to guide policy appraisal. The branch of economic theory known as welfare economics concentrates on providing guidance about the problems of policymaking. The theory examines both what

Jan 1, 1985

By Robert A. Jankowski, Ellsworth R. Spencer, Jay F. Colinet

Longwall mining is the most productive method of under- ground coal mining in the United States (US.), and record levels of production have been reached in recent years. These ever-improving production levels have the potential to generate significantly higher quantities of respirable dust. Consequently, the longwall industry continues to struggle with controlling dust liberation and maintaining compliance with the federally-mandated respirable dust standard. In response, longwall operators have in- creased the application of primary dust controls, airflow and water flow, in an effort to improve respirable dust control and reduce worker exposure. Pittsburgh Research Center (PRC) personnel conducted dust surveys at 13 longwalls operating throughout the U.S. and collected information to: identify current operating practices on these longwalls, identify the types of dust controls in use, document the levels at which these controls are being applied, and measure the respirable dust levels present. This data was analyzed to quantify the dust levels generated by the major sources on the longwall section and to evaluate the relative effectiveness of the control technologies in use.

Jan 1, 1997

By Dan S. Nilsson

Small-scale mines are today expected to provide much of the increased production of metals, industnial minerals and coal this country demands in the future. But what is the size trend in the mining industry?

Jan 1, 1980

By S. Zaman, F. F. Aplan, Franklin T. Davis

This section deals with the oxides of heavy metals, namely, columbium and tantalum, rare earths, chrome, manganese, titanium, tin, and tungsten. Table I contains the production figures for each of these commodities in the US and in the world in 1977. Specifications for concentrates are also summarized as well as prices for concentrates in 1977. In each chapter an attempt has been made to describe the more common commercial mineral involved with the commodity and the processes used to recover and concentrate the minerals, as well as geographical areas where these processes are utilized.

Jan 1, 1985

By P. M. Soupios

The study of soft soil (wastes above the rock bed) an issue of great importance in civil engineering, is usually addressed by drilling boreholes. This method is rather expensive and time-consuming and although the information obtained is usually accurate, on the other hand it is much localized. Recently published researches have demonstrated the ability of the combination of geophysical exploration methods to estimate the thickness of deposited wastes, which provides the layered structure of the study area and certain, method depended, mechanical parameters as well. By theory, the frequency of resonance of an upper layer is a function of its thickness and the average shear velocity in it. Furthermore, the application of H/V spectral ratios of micro-tremors is a fast, straight forward and cost effective methodology, yielding the determination of the main resonant frequency of the soil. Based on this framework, 20 microtremor measurements have been carried out in a Landfill in Heraklion-Crete. Some of these measurements were deliberately close to drilled sites, where the basement had been reached. Three electrical resistivity tomographies were also used, in order to define the landfill structure such as, thickness, determination of different wastes distribution in the study area and other parameters. In addition, estimation of predictive Vs using empirical relationship between shear velocity and penetration resistance (SPT?s) were also conducted. Knowing the thickness and the resonant frequency, we estimated the shear (Vs) velocity of the waste cover. The final Vs model was confirmed using the results from the Vs-SPT correlation. The combinative implementation of the above mentioned geophysical and geotechnical methods have successfully defined geometrical and geotechnical/geophysical characteristics of the area under investigation in a fast and cost effective way.

Jan 1, 2005

By Yi Luo

Subsidence events occurred over inactive room and pillar (R&P) mines, including abandoned mines or sealed portions of active mines, are classified as unplanned subsidence because of their timing and distribution are unpredictable. When investigating such subsidence cases, many uncertainties exist and disputes often focused on whether the observed structural damages are caused by mine subsidence or other natural or artificial causes. However, solid evidences to identify the causes are often lacking. In order to conduct a thorough and impartial investigation, good knowledge in subsidence theories a

Jan 1, 2009

By Paul C. Schmall, John F. Donohoe, Arthur B. Corwin

In the aftermath of the September 11th attack on the World Trade Center, groundwater control was of immediate concern. Water in?ow from the adjacent Hudson River through the compromised slurry wall ‘bathtub’ surrounding the site, ruptured water and sewer mains, and saturation from fire hoses all contributed to an already critical situation, further hampering the recovery and rehabilitation effort. An extensive pumping and deep well installation program was initiated, focused on reducing the hydrostatic loading to the severely damaged perimeter slurry wall.

Jan 1, 2003

By H. H. Murray

Tactical R & D is research and development for a specific application or applications. The mineral scientist has to define and understand the physical and chemical parameters required for a specific or potential application. Then the researcher must know the structure and composition of the mineral and its physical and chemical properties. Can these properties be changed by processing particle size and shape modification, and surface chemical treatment? Examples of tactical R & D in the industrial minerals area will be described.

Jan 1, 2003