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By P. D. Rao, D. E. Walsh, W. W. McClintock

A column flotation system was designed to conduct release analyses on a very finely disseminated, stratiform copper ore from the Denali Copper Prospect in Alaska. Chalcopyrite is finely disseminated in a carbonate matrix, and pyrite is disseminated in both the chalcopyrite and the gangue. Grinding to -20 µm is required for adequate liberation. A 25-mm x 2.4-m glass flotation column was designed. The ore and its flotation tailings were repeatedly floated to obtain a rougher concentrate. The rougher concentrate was then repeatedly floated to produce release fractions. These fractions were analyzed for copper, iron, calcium and magnesium, and release curves were plotted. The procedure was replicated at each of two grinds, i.e., 99% and 88% passing 37 µm (400 mesh). The procedure should find application for flotation characterization and process selection. Bond grindability testing was also conducted.

Jan 1, 1996

Many organisations, including those in the resources industry have Board-level endorsed principles on sustainability. A key challenge, however, is how to systematically integrate these high-level principles into the design and operation of mineral processing plants. In an effort to meet this challenge the Sustainable Operations framework, called SUSOP®, was conceived and developed through the Corporative Research Centre for Sustainable Resource Processing (CSRP) in Australia. Somewhat analogous to HAZOP (Hazard and Operability Studies) which is well entrenched in the resources industry, the key aim of SUSOP® is to produce a holistic, systematic and rigorous methodology for identifying and assessing sustainability opportunities and risks. This paper argues the need for such a sustainability framework, presents the key elements of SUSOP®, highlights how case studies enhanced its development and articulates the reasons why such a framework will have growing importance into the future.

Jan 1, 2011

By George E. Niewiadomski

The exposure of miners to radon gas and its airborne daughter products is a serious health problem which has long been recognized in the uranium mining industry. The association of high exposure to alpha particle emitters with incidence of lung cancer is well established. There continues to be a pressing need to reduce and eventually eliminate the high incidence of occupational lung cancer among uranium miners through the development of new and improved measurement and control technologies. This paper highlights the current efforts of the Bureau of Mines radiation hazards research program. It is aimed at obtaining a fundamental understanding of the behavior and transport of radon and radon daughters, developing more accurate and reliable instruments and measurement methods and developing cost-effective control techniques. Also discussed are the most recent accomplishments and the future research plans of the program.

Jan 1, 1981

Land management planning is an important issue in all jurisdictions, especially as it relates to mineral development. These planning documents are prepared at different intervals and reflect the realities at the time that they were prepared. The Seven Questions to Sustainability developed during the North American Process of the Mining, Minerals and Sustainable Development (MMSD) project are proposed for the evaluation of Land Use Plans as they relate to Mineral Development. This paper provides the background to the Seven Questions to Sustainability and how it can be applied to the evaluation of land use plans with specific reference to Resource Management Plans developed by the U. S. Department of the Interior?s Bureau of Land Management in Nevada. While this paper is focused on Nevada, the approach is broadly applicable and may be used in other planning regimes.

Jan 1, 2007

By B. K. Mishra, R. K. Rajamani, R. Venugopal, P. Songfack

Millsoft is a computer-simulation software that predicts the performance of large industrial grinding mills. This software surpasses all other tumbling-mill analysis techniques available today because it is based on fundamental laws of physics instead of empirical correlations. Graphical user interface (GUI) forms simplify the specification of the following design and operating parameters: mill diameter, length, speed, charge density and size distribution, lifter material and geometry. All of these parameters are taken into account in the discrete element numerical technique that constitutes the essence of the simulation software. In turn, the software produces a visual animation of grinding-charge motion, predicts mill power and gives the distribution of impact energy. In this paper, a case study of an 8.5-m-(28 ft-) diam SAG mill is used to illustrate the application of Millsoft for mill design and trouble shooting.

Jan 1, 2000

By J de Cuyper, S. Ramachandran, L. A. Vazquez, N. L. Grauerholz, W. Freyberger

A novel process is described for the selective flotation of scheelite from low-grade (- 0.5% W03) tungsten ores having appreciable quantities of calcareous and siliceous gangue minerals. Specifically developed for the Tempiute, Nevada facility of Union Carbide, the process yields tungsten concentrates exceeding 15 percent W03 with at least 85 percent recovery. This condition was not achieved through conventional processes. This process consists of conditioning the ore pulp with judicious amounts of lime, followed by soda ash and sodium silicate as modifiers. The scheelite is then floated using a mixture of oleic and naphthenic acids as collector. Contrary to the common observation as to the deleterious effects of calcium in fatty acid flotation systems, lime addition is found to be beneficial in achieving satisfactory results. The process has also shown excellent results on a Brazilian scheelite ore.

Jan 1, 1976

By D. W. Park

The Longwall Strata-Control and Maintenance System (LoSCo-MS) is a software and data-communication system developed at the University of Alabama. This system integrates real-time shield monitoring, data presentation, analysis and the forecasting of forthcoming events. The main objective of this system is to provide stability information on longwall panels, including excessive shield load, low setting pressure, leg leakage, poor shield performance and imminent maintenance problems. Analyses of various mining and geological parameters were also performed to determine past and present roof characteristics and to forecast roof loading patterns for the following mining cycles, the next periodic weighting, etc. A local coal mine in the Warrior Coal Basin has adopted this system to provide daily evaluation of ground stability and maintenance problems in their longwall panels. Two years of experience with this system is covered in this paper.

Jan 1, 2000

By R. S. Sheeta, C. J. Bise

The search for a more effective means of coping with methane liberation has resulted in the expanded use of seam degasification. Its advantages are measured not only in reducing the hazards due to methane, but also in producing a marketable commodity, the gas itself. However, the success of a methane drainage system is the culmination of many complex factors, the most important being the coal seam permeability. The two most popular drainage techniques used in mining today are the vertically stimulated borehole method and the in-seam horizontal borehole method. The objective of this paper is to determine the permeability range in which the selection of the degasification technique is based primarily on equipment and economic analysis. A discussion of the equipment involved will be incorporated into examples evaluated by the Pennsylvania State University coal methane simulation model.

Jan 1, 1990

By Osvaldo Bascur

Large metallurgical complexes have more data than a small city and much of it is "real time," changing rapidly as internal and external conditions evolve. As corporations buy and sell assets and reengineer their staff, the structures and tools that were used to understand these data are lost. This results in significant deterioration in the ability to maintain a "smart" operation. The solution is to use the sophisticated new tools built for the Internet so as to leverage information in a familiar browser format that people can use and understand. This paper describes the use of Internet technologies with plant data. Examples are drawn from existing industrial sites. Users must project where this technology will lead - standing still is the most dangerous philosophy and the only one guaranteed to be obsolete. These examples show the way to leverage existing workers with information technology.

Jan 1, 2000

By D. Borrowman

Attrition of activated carbon in either the carbon-in-pulp (CIP) or carbon-in-leach (CIL) method of gold extraction can lead to, at the least, loss of expensive carbon that has to be made up, and at the worst, loss of both the carbon and any gold that was attached to it. Carbon attrition therefore represents a significant factor in both the efficiency and cost of the extraction process, and efforts to reduce attrition through process and equipment selection pay dividends. In evaluating carbon attrition potential, one would note that an individual carbon particle is in jeopardy virtually any time it is in motion. Since the motivators of this motion are primary centrifugal pumps, the purpose of this paper is to review the current styles of these pumps now in use and to examine their performance in minimizing carbon attrition.

Jan 1, 1992

By Gy. Deák

The Romanian mining and especially the salt mining industry is going through a restructuring phase; among others it has to respect the European Environment Act. One of the most important deficits of the salt mining industry is the implementation of monitoring systems for geomechanics phenomena, in order to develop an important information database and form a real base for salt mines stability, prediction and prevention measures. Monitoring system solutions, involving discontinuous and continuous measurements of displacement / deformation fields, around underground excavations, are presented and discussed. In addition, a case study for the stability prediction of an experimental salt off-set, located in the Praid salt mine, using DKRControl method, is presented. The two monitoring systems use different tools, namely measuring tapes (to determine distance between markers in T-D station) and ultrasonic transducers (SM-TDA equipment).

Jan 1, 2006

By Daniel J. Turk, William R. Banning, John Paterson, Thomas J. Weitz, Michael L. Clark

Introduction Pegasus Gold's Montana Tunnels mine is a large surface gold, silver, lead, and zinc mine located 37 km (23 miles) south of Helena in southwestern Montana. Milling operations commenced in late March 1987. The concentrator achieved full production in May that year after undergo¬ing several modifications and improvements. Production for 1988 is projected to be 2.48 t ,80,000 oz) of gold, 34.2 t (1.1 million oz) of silver, along with 8.5 kt (9400 st) of lead, and 22.6 kt (25,000 st) of zinc from lead and zinc concentrates. Mill throughput currently averages 11.7 kt/d (12,900 stpd), compared to the origi¬nally designed capacity of 11.3 kt/d (12,500 stpd). Cash production costs, net of bypro¬duct revenues for the third quarter 1988, were below $3.20/g ($100 per oz). The introduction of ore to the concen¬trator marked the culmination of 12 years ex¬ploration, evaluation, and development. Initial milling operations encountered diffi¬culties with the circuit as designed. As a result, several modifications and improve¬ments were made to the plant. This article is intended to assist other companies developing projects of this type and complexity. It discusses the mine's de¬velopment from feasibility and construction through start-up. The operation, as it exists today, is reviewed including the modifica¬tions and improvements made since start-up. History The mine is situated in Jefferson County, MT within the historic Corbin-Wickes min¬ing district. Underground mining began in 1864 and flourished until the early 1900s. Between 1864 and 1900 the vein deposits in the district produced about $41 million dol¬lars worth of lead and silver ores containing subordinate amounts of zinc, copper, and gold. At various times, three smelters were operated in the area.

Jan 1, 1989

By Werner A. Ruemmele, Steven R. Wardwell

INTRODUCTION The first phase of the Los Angeles Metro Rail Project consists of 7.1 km (4.4 miles) of subway and stations running through downtown Los Angeles from Union Station to MacArthur Park. Shank-Ohbayashi has two of the tunnelling contracts on this initial phase: A-171 and A-146. Contract A-171, the Wilshire/Alvarado Line, involves tunnel construction beneath 7th Street from the 7th/Flower Station to the Wilshire/Alvarado Station. The project consists of the excavation and lining of 3000 m (9900 ft) of twin-bore, 6.7 m (22 ft) excavated diameter, 5.5 m (18 ft) finished diameter subway tunnels. Contract A-146, the 5th/Hill to 7th/Flower Tunnels, comprises 1220 m (4000 L.F.) of twin-bore tunnel identical in cross section to the tunnels in Contract A-171. The majority of the excavation on Contract A-171 is beneath city streets in a weak siltstone/claystone bedrock with cover varying between 10 m and 25 m (32 ft and 82 ft) to the street surface. Approaching the 7th/Flower Station some fine-grained alluvium is encountered. The tunnels on both contracts are excavated with an open face digger equipped shield. On Contract A-146 the tunnel alignment is a 305 m radius curve of approximately 550 m (1800 L.F.) length underneath several multi-storied buildings of various construction. Excavation is still ongoing on Contract A-146. The contractor's choice for initial tunnel support on both contracts is a system of precast concrete segments similar to what the contractor had used on 7 miles of tunnel in Phoenix, Arizona, for the Arizona Department of Highways.

Jan 1, 1989

By Victor J. Scaravilli

This report is based on experience developed on the construction of one contract for the Buffalo, New York subway. The Buffalo subway is under construction for the Niagara Frontier Transportation Authority and is called the LRRT-Light Rail Rapid Transit or more commonly the Metro. The Initial Route of the Buffalo subway construction started early in 1979 and is scheduled for completion in May, 1984. The initial system includes 5.2 miles of underground construction, 1.3 miles at grade for a total of 6.5 miles of subway system. A total of fourteen stations, eight underground and six at grade are included on the system. The Initial Route has a planned expansion to 17.3 miles in the future. On January 15, 1979, a Joint Venture of S & M Constructors, Inc., Solon, Ohio, James McHugh Construction Co., Chicago, Illinois, and Kenny Construction Company, Wheeling, Illinois, was awarded contract 100031, the Line Tunnels from Amherst Street to South Campus in northcentral Buffalo between Delaware Park and the State University, (see Fig. 1, Location Plan) This $35,000,000.00 contract was designed by Hatch Associates Consultants, Inc., Buffalo, N.Y. The Notice to Proceed was issued January 15, 1979 and the scheduled completion date is August 18, 1981. The project consists of two parallel rock tunnels with a minimum excavated diam of 18 ft 0 in. and a final concrete lining of 16 ft 0 in. diam. The tunnels total 14,630 linear ft. In addition to the tunnels, contract C-31 includes four shafts, an underground pump station, three cross passage connections, and other minor work items. (see Fig. 2, C-31 Project Plan and Profile) The tunnels were constructed primarily within the Bertie Formation, an approximately 50 foot thick moderately fractured to massive, dolo-

Jan 1, 1981

By Edward H. Opitz

Much has been written recently about the Henderson Mine Project in Colorado being developed by American Metal Climax, Inc. To briefly recap the project, AMAX has an ore body, containing about 300 million tons of proven and probable molybdenum ore which is located under Red Mountain on the eastern slope of the Continental Divide. The mill, however, will be located on the western slope in the Williams Fork Valley where water and space for waste disposal are more available. AMAX will carry the ore by remote controlled trains from a gathering level underground at the mine, through a ten (10) mile tunnel under the Continental Divide and thence along a five (5) mile surface railroad to the mill site. One of the more challenging facets of the project is the western portion of the ten (10) mile tunnel being driven by Dravo Corporation through difficult ground conditions, downgrade, toward the Continental Divide. The tunnel is a 16'-6" wide by 15' high horseshoe, which runs in a straight line and drops at a constant three percent (3%) grade from the West Portal to the ore zone. Dravo's portion is anticipated to be about 6 1/2 miles long and includes permanent pumping stations located every 4,900 linear feet (lf) permanent rectifier stations every 12,5001f, and one (1) 1,560 ventilation shaft. The western portion of the tunnel lies in the Idaho Springs formation, a mixture of gneiss and schist with some granitic intrusions. Toward the Continental Divide a transition into Silver Plume Granite is expected to occur. Preconstruction geologic information indicated the Idaho Springs and Silver Plume formations to be basically competent with some faulted and altered areas. It

Jan 1, 1974

By Pierre J. Wauters, Eddy J. Jacques

Starting up a fan or modifying its setting point either by rotational speed variations or blade angle changes, obviously results in new ventilation conditions in the network, which is, of course, the object of the operation. However, since transient phenomena may then occur, particularly in complex networks, there may be a need to simulate these situations prior to any action. This is all the more true, if we are dealing with a multiple interactive fan sys- tem. Simulations with a transient model have shown that the flow in certain airways could be temporarily reversed due to the pres- sure variations that reach both its ends with a different time lag. This phenomenon may cause dangerous situations to occur in cases of fire or outburst of methane. It is also true that the air flow could be reversed in secondary and less powerful fans, while still rotating in the normal direction. The study and the experimental investigation of the extension of the reverse flow characteristic is therefore justified from two points of view : • a numerical simulation model for transient flow conditions must be capable of handling temporary reversed flows, and thus have appropriate fan characteristic curves available over the entire operating domain; • while operating fans, reversed flows should be avoided or at least reduced. Therefore, the design of start-up procedures or real time control algorithms should take these phenomena into account. A particular interesting application is the operating of two fans in parallel. In order to investigate experimentally the characteristic curves of a fan under reversed flow conditions a small scale model was built. This facility was designed in such a manner that it was possible to carry out experiments concerning flow reversions and to try out sequential start-up procedures for two fans in parallel.

Jan 1, 1997

By W. N. Key, L. C. Acton

Freeport Minerals Co.'s Ertsberg East underground operation typifies the cliche that all the "easy" ore deposits have already been found. Despite its location, in a remote Indonesian rain forest, and the effort and expense required to develop the ore body, the mine was developed on schedule, under budget, and with minimal disruption of the adjacent open-pit mining operation. Development of the Ertsberg East copper, gold, and silver ore body took less than two years after exploration drilling and feasibility studies were completed. In addition, the project came in well under its targeted budget of $101.5 million. Initial block caving and underground ore production took place last year. About 3 kt/d of Ertsberg's total 8.6 kt/d ore production is currently mined underground. This will increase to 5.4 kt/d by year's end. Underground operations will eventually account for all of Ertsberg's production, as the open-pit ore body is depleted. Freeport Minerals is currently studying the possibility of increasing total Ertsberg East production tonnage to 10.5 kt/d by 1983. The equipment, work practices, and development methods at Ertsberg East (Gunung Bijih Timur or "GBT"), while typical of other block caving mines, were modified for rapid mine development and maximum ore recovery. Located in the Irian Jaya province, "Gunung Bijih" is the Indonesian expression for the Dutch "Ertsberg" that in English means "ore mountain." "Timur" means "east" and relates to the fact that the new underground ore body lies about 1 km east of the open pit. The area surrounding GBT is mountainous, with peaks from 4.2-5 km. The underground mine adit and surface plant are located at a 3.6-km elevation. The mine, 4° south of the equator, gets 5.1 m/a of rain, but has an average daily temperature of only 13°C because of the mine's elevation.

Jan 7, 1981

By R. S. Shoemaker

It is said that there is nothing new under the sun and this is certainly true about refractory gold Ores. Ores which have been refractory to treatment have been the bane of the Metallurgist's life ever since gold has been recognized as a metal valued for its indestructability, malleability and beauty. Webster's Dictionary defines "Refractory" as; "Resisting control or authority, stubborn, resistant to treatment or cure, unresponsive to stimuli, difficult to corrode or draw out," And gives as a synonym the word "unruly." I don't think any metallurgist would disagree with these definitions as they quite accurately describe refractory gold ores as we know them and I wouldn't be a bit surprised if many of you in this room today had applied far stonger language to your own refractory ores in the course of your metallurgical test programs. Pliny the elder put it very well when he wrote in 79 A.D., Gold is the first of man's follies, Silver the second." Perhaps Pliny was speaking of "unassayable gold" or "incipient gold." These are truly refrac tory ores which probably existed before Pliny's time and although many people have claimed to have solved their metallurgy the untold wealth that lies within them has never been bankable. On the other hand, Virgil is his Aenead, could very well have been speaking of refractory ores when he wrote; "Quid non mortalia pectora cogis, auri sacra fames!" which translates as, Accursed thirst for gold! What doest thou not compel mortals to do. Certainly, gold was extremely rare at that time because it had to be recovered by much labor from the then refractory ores and their refractoriness caused the early metallurgists (or alchemists if you will) to seek an easier way to produce it; thus the long and fruitless search for the "philosopher 's stone" which would aid in turn-

Jan 1, 1990

By Anna Marabini

This paper provides a summary of the studies performed over a period of more than fifteen years by the Italian National Research Council's Mineral Processing Institute in Rome to develop applications for the use of chelating reagents in the flotation of metallic minerals. A description is given of the various phases through which the studied progressed, starting with the combined use of commercial chelating reagents and a neutral oil and then moving on to the synthesis of new long-chain chelate collectors for the flotation of sulphide and oxidized Pb, Zn and Cu minerals. After a series of preliminary tests which confirmed the possibility of floating various metallic minerals with commercial reagents containing chelating groups exerting specific action on given cations, the studies were addressed to the development of a theoretical method of choosing chelating groups that exert selective action on one metallic mineral rather than others. The theoretical approach was based on thermodynamic data concerning the chemical equilibria in solution. The validity of the method has been proved in numerous cases by flotation tests on pure minerals. Subsequently the research was directed towards the design and synthesis of reagents with a mixed aliphatic-aromatic structure containing chelating groups for Pb and Zn and an alcoxyl chain of various length, position and configuration. The flotation results obtained on oxidized and mixed Zn-Pb ores provided interesting pointers for designing the nonpolar portion. The structural criteria identified via these studies were interpreted on the basis of chemical and steric considerations. A description is given of a new synthetic chelate collector which is effective in the selective flotation of Cu minerals from complex sulphides. The fact that this reagents is more selective than xanthate is demonstrated by comparative flotation tests on actual ores.

Jan 1, 1994

By L. Alan Weakly

This paper was presented at the ‘17th U. S. Symposium on Rock Mechanics’ on August 29, 1976, at Snowbird, Utah, at the SME-AIME Fall Meeting on September 1, 1976, at Denver, Colorado, and at the Polish-American conference on Ground Control in Room-and-Pillar Mining on August 7, 1980 at Southern Illinois University, Carbondale, Illinois. Introduction The purpose of this paper is to present a viable method of reinforcing rock pillars by utilizing fully grouted reinforcing steel and a cement- fly ash mortar. Although the fully bonded bolt concept is not new as exemplified by the present widespread use of resin bolts within United States mines and by the use of cement grouted reinforcing used as back pins in the Kiruna Iron Ore Mine in northern Sweden, (1)(2)the method of stabilizing mine pillars with fully bonded reinforcing is new. This method, called the "grout-rebar system", was first incorporated at St. Joe Minerals Corporation's Fletcher Mine in December of 1972. The system was used on an emergency basis before extensive research on the mechanics of the system could be completed. Since Decmeber of 1972, however, approximately 206 pillars have been reinforced at Fletcher and the system is currently being used on a regular basis at two other St. Joe mines and at two competitor mines in the area. Basically, this paper is a case study of the efforts, research and results of utilizing the grout-rebar system, on a selective basis, at the Fletcher Mine. In addition to information about the system, this paper will explain in detail the three rock mechanics instruments developed by St. Joe and used to measure and monitor rock movement to validate the group-rebar system.

Jan 1, 1982