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By Jr. Denton

This U.S. Bureau of Mines report presents the documentation for HEAPREC, a methodology for calculating reclamation performance bonds for cyanide heap leach operations. HEAPREC is a template developed for use with Lotus 1-2-33 release 2.01 or newer software. The report is presented in step-by-step "user's manual" format. Appendices contain detailed background and reference material on performance bonding, cyanide detoxification regulation, cyanide detoxification methods, general mine reclamation procedures, and an example bond calculation.

Jan 1, 1992

By Arcy, D&apos Banister

The productive potential of the Nation's principal active and inactive silver mining districts has been evaluated, using 1964 economic conditions and assumed silver prices ranging up to $3 per ounce. On this basis, the United States has an estimated 5 billion ounces of unmined silver, excluding minor byproduct silver in gold deposits. Approximately 3.5 billion ounces are contained in deposits requiring higher silver prices to be economically minable, and about 1.3 billion ounces are in currently operating mines. An analysis of silver consumption trends since 1954 indicates that the free world industrial market will climb to nearly 800 million ounces annually by 1985. U.S. industrial silver consumption has been projected to increase at an annual rate of 4 percent from 1965 to 1985. Average annual increase for the remainder of the free world has been 8.1 percent since 1953; this is expected to level off with an estimated average increase of 5 percent to 1975 and 4 percent from 1976 to 1985. Foreign silver production has, in the past, exceeded consumption, but in 1960 the supply deficit was over 100 million ounces. U.S. production, also traditionally exceeding demand, was suddenly overtaken at the start of World War II. By 1964 the annual deficit, excluding coinage, was over 84 million ounces. World coinage requirements of silver are fast declining and expected to total only 25 million ounces annually by 1985. In fact, coins are already becoming major short-term source of silver to fill the large deficit between industrial demand and current production. The larger, long-term deficit (to 1985, the limit of this study) must be balanced by silver from the hoards and new production from silver deposits. Eventually all of the deficit must be met by new production or silver prices will rise until consumption is greatly curtailed. To balance free world supply and demand, it is estimated that the free world must produce an additional 85 million ounces by 1975 and 375 million ounces by 1985. The estimated proportion expected from U.S. deposits is 17 million ounces by 1975 and 74 million ounces by 1985.

Jan 1, 1969

By Michael G. Batten, Brian D. Keaney

]The Virginia Department of Transportation (VDOT) and the harbors on the James River routinely use precast concrete piles founded in the Yorktown formation to support bridges and other coastal structures. However, axial pile resistances for large diameter piles in this area have been historically overestimated on past projects. This may be due to a common assumption that very large unit end bearing resistance will be developed for a large diameter displacement pile that is driven a significant depth. This assumption is integrated in the Nordlund (1963; 1979) method which is commonly used to estimate axial pile resistance for bridge foundations. A static and dynamic pile load testing program was implemented as part of the Hampton Roads Bridge and Tunnel Expansion project in Norfolk, VA in the James River. A primary objective of this program was to calibrate an axial resistance calculation method against the measured load test results. A method developed by Eslami and Fellenius (1997) that uses CPTu data directly was effective at calibrating to the measured load test results, and allowed for clearer interpretation of the unit resistance values than indirect, semi-empirical methods that require interpretation of soil friction angle and undrained shear strength.

Sep 8, 2021

By John W. Buch

This is the first progress report to be released on the anthracite, mechanical mining research and engineering development program of the Bureau of Mines. This phase of Bureau work, which was initiated as an aid to stimulating wartime production of anthracite, has been continued after the war to assist primarily in improving the general economic position of the anthracite industry. Field work was started in. the 1945 fiscal year with the cooperation of an advisory committee representing management, labor, and the Commonwealth of Pennsylvania. For a beginning, several matters were suggested by members of this advisory committee as being worthy of investigation, and sections of underground mines yore offered for test purposes. Among the suggestions accepted for investigation was the problem of increasing the rate of advance for driving gangways in thin, steeply pitching anthracite beds 4 to 6 feet thick and pitching 60 degrees or more. The problem was undertaken as a field study, and this report relates to accomplishments on this project to June 30, 1947.

Jan 1, 1949

By D. R. Spears

As part of its mission to develop technology to assure a continuing supply of minerals, the US Bureau of Mines has investigated the flocculation of a Stillwater, MT, chromite ore. The ore was flocculated at different solids contents and at different stirring speeds to determine the importance and effect of hydrodynamic factors. In acidic and basic pH, the chromite ore was flocculated with high molecular weight polyacrylamides differing in the degree of hydrolysis. Polyacrylamides were found to bind to chromite ore particles through hydrogen bonding. The anionicity of the polymer and the pH affected the degree of polymer-particle interaction, which in turn affected polymer conformation at the surface. A polymer conformation with many loops and tails was used to explain high flocculation efficiency. It was found that such a conformation could compensate for poor hydrodynamic conditions.

Jan 1, 1992

This publication summarizes, for potential contractors and other interested parties, the proposed research, development, and demonstration contract projects programed by the Bureau of Mines for fiscal year 1977 (October 1, 1976-September 30, 1977) under its Advancing Coal Mining Technology program. The objective of these projects is to provide an ordered and sequenced series of advances toward the overall goal of providing the system technology required to increase the productivity of the coal mining process.

Jan 1, 1977

By M. S. Tsai

Recovery of uranium from wet-process phosphoric acid is a newly developed source of uranium. Many processes have been developed but the OPAP (octylphenyl acid phosphate) process is still the valuable one because the OPAP reagent compound has the high extraction ,power and cheap cost. The OPAP process was already studied by murthy(1) in 1970 and its complete process flow sheet was first fulfilled by F.T. Hurst(2) in 1974. WCFC(3) (western Co-op Fertilizer Ltd.) in cooperation with ESI (Earth Science Inc.) set up the OPAP uranium recovery pilot plant in Canada in 1978. We have studied the OPAP process since 1974 and first improved the OPAP extractant by proper adjustment of the DOPAP/MOPAP mole ratio with CH3OH-H20 method, resulting in shortening the phase separation time and avoiding the precipitation occurrence in our process. Second, we utilize the reduction and oxidation occurring by DC power supply on either side of the membrane to achieve the extraction and stripping at the same time. An improved OPAP process in which high recovery yield of uranium and acid uncontaminated by iron has been developed in our laboratory.

Jan 1, 1982

By Larissa Koroznikova, Steve Durkin, Patrick Bouwmeester, Michael Tuck

In currently used mining methods, blasting techniques often causes dilution of valuable ore and results in costly processing requirements. In the context of narrow vein mining of thin and highly concentrated orebodies there is a need of a mining method that can reduce dilution in order to remain economically viable. This research project explored the viability of a new mining technology, thermal fragmentation, in narrow vein mining. Thermal fragmentation technology uses a flame jet to produce extreme heat that spalls the surrounding rock to a strategically located drill hole, as an alternative to traditional blasting. This paper creates a net present value (NPV) model of a mining method using thermal fragmentation, as well as for an existing method used for narrow vein mining; comparisons and evaluations were made regarding the feasibility of the new technology. It was found that while overall costs for thermal fragmentation were relatively high, reductions in wages, haulage and processing costs, as well as increased productivity and ore recovery, meant that the new method would improve the financial performance of any operation. These results identify that there is an opportunity to introduce the thermal fragmentation technology to narrow vein mines within Australia, in order to lower costs and increase profit.

By Dix, E. H.

THE percentage of manganese used in commercial aluminum alloys is small, and yet this element is an important addition to some very valuable alloys. When used alone with commercial aluminum containing iron and silicon as impurities, the usual percentage in wrought materials is from 1 to 1.5 per cent., whereas castings may contain as much as 2 per cent. An aluminum-manganese alloy containing nominally 1.25 per cent. manganese is much used in sheet form for the manufacture of cooking utensils and other articles requiring a little greater strength and hardness than could be obtained with commercially pure aluminum. It is also used for various purposes in the form of rods, tubes and pipes. The aluminum-manganese alloys, both wrought 'and cast, offer excellent resistance to many kinds of corrosion attack. The U. S. Naval Gun Factory uses an aluminum alloy containing from 1 to 2 per cent. each of copper and manganese, for both castings and forgings. Manganese is also used, up to about 1 per cent., as a minor alloying .element in several of the strong aluminum alloys of the duralumin type. It is felt that the role of this element when thus used has not been fully understood, but it is believed that the results obtained in this investigation will throw additional light on the subject. The earlier work on the system aluminum-manganese was general in nature, and no detailed investigations of the relations existent in the useful aluminum-rich alloys have been reported. Guilletl1in 1902 surveyed the system, and Hendrichs2 in 1908 published an equilibrium diagram which, although based on .few data, is often used in the literature. Fragmentary work has also been done by other investigators."

Jan 1, 1927

By P. Gelfi, J. Vanderbeek, J. Enriquez

"The Cerro Verde copper-molybdenum mining complex is located near Arequipa, Peru. A 108,000 t/d copper concentrator (C1 concentrator) commenced operation in late 2006 and was debottlenecked to a 120,000 t/d capacity in 2011. A feasibility study, initiated in May 2010, assessed the potential for expanding the processing rate of the large Cerro Verde sulfide reserve via the installation of a second, stand-alone, concentrator (C2 concentrator) capable of processing a nominal 240,000 t/d ore. The feasibility study was successful and the project advanced through engineering, permitting and construction. Ramp up to nameplate capacity was ahead of schedule. The overall project was completed on schedule and within budget. The details of the project and supporting components are described. The design philosophy and design basis of the concentrator facilities are discussed as are factors that influenced the concentrator layout. Risk mitigation features included in the design are reviewed. The factors that drove the successful and rapid ramp up to nameplate capacity are discussed. Operational experiences in the first year of plant operation and project lessons learned are described. INTRODUCTION/BACKGROUND Sociedad Minera Cerro Verde S.A.A. (SMCV) operates a copper mine near Arequipa in southern Peru. Small scale operations operated intermittently until 1970 when the deposit reverted to the ownership of Minero Perú S.A (Peruvian government). Minero Perú S.A. commenced mining and processing of oxide reserves in 1972 and placed an SX-EW plant into production in 1976. The ownership of the property has changed hands several times over the years. Minero Perú sold Cerro Verde to Cyprus Climax Metals in 1994. Cyprus was acquired by Phelps Dodge in 1999. Freeport-McMoRan (FCX) acquired Phelps Dodge in 2007. Several studies were undertaken during the 1990’s that tried to establish the economic justification to process the large primary sulfide resource that underlies the surface oxide deposit. None of these studies produced an economic conclusion until a feasibility study was completed by Phelps Dodge and SMCV in 2004. This study provided the economic justification for the construction of a 108,000 t/d concentrator during 2005 and 2006. The key to the success of this study was identifying a water source that was sufficient to support processing economies of scale. Concentrator operations commenced in late 2006. The original design production rate of 108,000 t/d was achieved on a 30 day moving average basis on the 266th day after ore was first introduced. During 2009, studies and evaluations were performed that had the objective of addressing observed concentrator bottlenecks to allow a production rate of 120,000 t/d to be achieved. The 120,000 t/d figure represents the sustainable production limits associated with the installed primary crusher and tailing thickeners which would have been prohibitively expensive to upgrade. Debottlenecking activities were implemented during 2010 allowing sustained production rates of 120,000 t/d to be achieved."

Jan 1, 2017

By Gregg W. Davidson, J. Andrew McGlenn, Frank Huber

The Second Narrows Water Supply Tunnel will ensure system reliability in the event of a major earthquake and increase the Greater Vancouver Water District’s capacity to meet the long-term needs of a growing population. The tunnel will be 1,100 m long and 6.5 m in diameter (3,610 LF × 21.3 ft), constructed under Burrard Inlet between North Vancouver and Burnaby in British Columbia. It will be excavated through mixed ground conditions under high groundwater pressure, using a slurry TBM, between a 72 m (236 ft) deep shaft in soil and a 110 m (361 ft) deep shaft in rock. The completed tunnel will accommodate three large-diameter water mains that will be installed as part of the tunnel contract. This paper presents the project from design and contractor procurement, into the current construction stage describing some of the unique challenges encountered during the project development to date.

Jun 13, 2021

By J. M. B. Scarborough

This paper deals with measures taken to maintain effective operation of heavy-duty equipment in open-pit mining. at Pine Point, N.W.T., during periods of extreme cold weather. The points covered include equipment modifications designed to improve cold-weather performance, effective lubrication of machinery that is vulnerable to extreme cold and operating procedures designed to prevent equipment damage.

Jan 1, 1966

By L. W. Scott

This report presents an overview of explosionproof (X-P) enclosure research being conducted by the Bureau of Mines, This report emphasizes the increasing importance of research related to the safety con- siderations of X-P enclosures used in underground coal mines. Selected topics are included that summarize results of research in the areas of electrical clearances, reliability of enclosures with windows, safety factors in X-P enclosures, potting materials, performance tests for X-P enclosures, protection against high-voltage explosions, and innovative X-P devices.

Jan 1, 1985

By D. Lansburg

Electronic detonators are increasingly being used in today’s blasting in quarries, seismic, surface and underground mines. Electronic detonators offer several distinctive features over electric and non-el (shock tube) detonators including better timing accuracy resulting in excellent fragmentation and vibration control, field programmability and digital safety means. Because of the prerequisite electrical communications between the electronic detonators and the blasting machine, the layout or hook-up of these detonators can play an important role in obtaining the communication fidelity.

Jan 1, 2011

By Robin J. Batterham

The Bologna Process started in 1999 with a declaration signed by ministers from most European countries. As of 2012, the Bologna Process now has 47 participating countries (EHEA 2012). Overall, the Bologna process has demonstrably changed higher education in many countries to allow for considerably more flexibility in course offerings. Keywords: bologna model, education

Sep 1, 2012

By H. O. Hofman

INSTITUTE OF TECHNOLOGY, In deternlining experimentally the fusibility of clays, two kinds of methods may be distinguished—the direct and the indirect. Of the direct methods, that of Seger has found

Jan 1, 1899

By J. Miettunen

"The lining of a grinding mill has an important role in creating the conditions for the grinding process. The main purpose of the lining is to transfer the energy taken by the mill motor to the contents of a mill. The power draw curve of the mill, if measured with sufficiently short intervals, describes how well the lining works in lifting and mixing the material to be ground.The power draw curve can also be used for determining the volumetric filling of a mill. This new measuring technique was developed at the Pyhasalmi concentrator in 1989-90. The measuring device with its PC-connections offers an excellent tool for controlling volumetric mill filling, for maximizing throughput and for research purpose (e.g. process studies, mill linings design).The paper describes the new method and the results achieved at Outokumpu's concentrators.INTRODUCTIONVarious methods have been developed for measuring mill load; weighing, noise, etc. Weighing is one of the most reliable methods but installing the sensor to existing mills is often difficult. Besides the load measurement does not indicate the volumetric filling if the specific gravity of the mill feed fluctuates. Noise measurement has often failed with its sensitivity to various disturbance sources.As known, the power draw measurement is one of the most accurate measurements in grinding circuits and therefore it has been utilized in sophisticated control, e.g. in power peak seeking algorithms for maintaining maximum grinding efficiency.About 10 years ago power oscillation measurement was developed at Pyhasalmi concentrator. In this method the amplitude of the oscillation caused by the lifters was measured. The oscillation amplitude and the mill filling has quite a good correlation and together with the power draw measurement it could be used for maximizing mill throughput (Koivistoinen and Miettunen, 1989). The main difficulties in this method were that the dependence between mill filling and the amplitude is unlinear and that the dependence also is individual for each mill.The method developed during 1989-90 is also based on the power oscillation but on its phase shift. In principle level of the material in a mill is measured. The method has been successfully used for maximizing throughput at Pyhasalmi and Enonkoski concentrators and at Harjavalta slag concentrator."

Jan 1, 1991

By D. Parks, A. Miller, M. McNinch, R. Jacksha

Each year, hundreds of mine workers are involved in machinery-related accidents. Many of these accidents involve inadequate or improper use of lockout/tagout (LOTO) procedures. To mitigate the occurrence of these accidents, new safety methods are needed to monitor access to hazardous areas around operating machinery, improve documentation/monitoring of maintenance that requires shutdown of the machinery, and prevent unexpected startup or movement during machine maintenance activities. The National Institute for Occupational Safety and Health (NIOSH) is currently researching the application of Internet of Things (IoT) technologies to provide intelligent machine monitoring as part of a comprehensive LOTO program. This paper introduces NIOSH’s two phase implementation of an IoT-based intelligent machine monitoring system. Phase one is the installation of a proof-of-concept system at a concrete batch plant, while phase two involves scaling up the system to include additional sensors, more detailed safety/performance metrics, proximity detection, and predictive failure analysis.

By T. A. Sullivan

The Bureau of Mines investigated modified sulfur concretes as one part of a program for utilizing sulfur in construction materials. The use of modified sulfur was studied as a means of preventing the stressing action in the concretes caused by the allotropic transformation of sulfur on solidification. Unmodified sulfur concretes have been prepared that have compression, flexural, and tensile strengths equivalent or better than Portland concretes. However, most of these concretes have been vulnerable to deterioration by weathering, temperature fluctuations, and freeze-thaw cycling. The sulfur was modified by reaction with dicyclopentadiene or dipentene before use as an aggregate binder. Sulfur concretes and modified sulfur concretes were pre-pared from acidic and basic type aggregates. Physical properties of the optimum mixtures were determined and compared with each other and with Portland cement concretes. The best results were obtained by reacting sulfur with 5 pct dicyclopentadiene to prepare modified sulfur concretes. Field testing of the concretes are in progress. Present results show that modified sulfur concretes are superior to unmodified sulfur concretes and equal or better than Portland concretes in compressive, flexural, and tensile strengths. Long-term aging characteristics of both modified and unmodified sulfur concretes are being determined.

Jan 1, 1976

The current boom being experienced by mining, coupled with a shortage of professionals, will mean those in the industry will have many choices. It may be easy to become carried away and run with the highest bid or the biggest promise. Without planning, however, the ærightÆ opportunity may be missed and there may be some long-term consequences. There are many choices of paths in the industry to suit work preferences, life cycles and to achieve a balanced life. People in mining have changed jobs and companies frequently û which means new leaders need to take greater responsibility in charting their own direction. Career options need to be carefully assessed and aligned to personal values and preferences. Emphasis is given on gaining site experience early on.This paper examines strategies for career planning, which incorporate life cycles, education and what is meant by a balanced lifestyle. Two tools are identified as being helpful in ensuring strategies can be successfully executed. They are ævisioningÆ and æinfluenceÆ.To make the mining industry more attractive, we need more creative solutions around advances in technology and organisation of work. It also needs the input and leadership of new entrants in to the industry to assist in its survival. New leaders are encouraged to voice a vision and effectively influence their companies. New leaders have little authority and need to learn how to effectively influence. We as a mining industry need to listen, be open-minded and give it a go.

Jan 1, 2004