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By A. Pinches, R. Winby, P. J. van Staden, M. K. Rhodes, P. C. Miller

This paper is a progress report on the commercialization of using bioleaching for base-metal concentrates. The paper focuses on bioleach processes for recovering copper from chalcopyrite and nickel/cobalt from pentlandite/pyrrhotite. Data is discussed from pilot-plant trials in which an overall recovery >95% was obtained for the bioleaching of copper from chalcopyrite. The pilot plant was operated in closed circuit with solvent extraction and electrowinning circuits for final metal recovery. For the bioleaching of nickel and cobalt from pentlandite/pyrrhotite, an overall recovery of 97% was achieved. Precipitation routines were used to produce a final nickel/cobalt product. The pilot plants were capable of treating a few kilograms of concentrate per day. Prominent features in the design of a 1-t/day (1.1-stpd) copper-bioleach demonstration plant for the treatment of chalcopyrite concentrate are discussed. The plant, which is now under design, will be constructed and operated based on the results obtained from the laboratory pilot-plant campaigns. Issues of scale-up for the demonstration plant, together with integration into upstream and downstream processing, are also addressed. Independently derived capital and operating costs are presented for a possible commercial plant. These cost studies indicate the principle economic issues in considering the application of bioleaching to the extraction of base metals. The benefits of bioleaching complex concentrates that are not amenable to physical beneficiation and economic treatment by conventional smelting are highlighted. Issues, such as the environmental aspects, that illustrate the benefits of bioleach technology are given.

Jan 1, 2000

By Gary B. Hemphill

The 345 km long Taiwan High Speed Rail Project will connect the island’s two most populated cities, Taipei and Kaohsiung. Kaohsiung is the world’s third busiest port. The 23 km of alignment on Contract C230 requires the construction of 5,879 m of shallow mined tunnels ranging from 137 m to 1,285 m in length. All nine of these tunnels are mined using NATM methodology. Two of the tunnels, T01 and T08 are in the Toukoshan Formation. This paper will discuss the mining methods, ground support design, and the instrumentation installed to monitor and verify its effectiveness in the two aforementioned tunnels.

Jan 1, 2003

By Frank S. Hicks, Y. Charles Guan, Glenn A. Gruber

This paper describes a two-part program funded by the Florida Institute of Phosphate Research and performed by Jacobs. The first part of the program was to examine the application of ultrasonic treatment to clean phosphate particle surfaces. Florida phosphate pebble and rougher flotation feeds were treated in an ultrasonic trough to remove clays. Also, the de-oiling of rougher concentrates by ultrasonic treatment was tested. In order to improve the clay removal efficiency, viscosities of primary cyclone overflow from six beneficiation plants were studied in the second part of the program. Viscosities for different samples at the same clay % solids vary significantly, and increase exponentially with clay % solids content for the same sample. A method of controlling cyclone operation using on-line viscosity measurements and pump box level sensors is proposed to logically improve primary cyclone performance.

Jan 1, 2002

By Richard C. Enochs

In order to clearly understand our process control system it is necessary to briefly discuss the various process control systems that were considered and why we chose our particular configuration. We considered Analog Systems, Computer Supervisory Systems, Computer Setpoint Systems, Direct Digital Systems and Direct Digital with Backup Systems. Our concept of these systems is illustrated in Figure 1 through Figure 5. We chose Direct Digital Control with Manual Backup because it had the greatest flexibility, ease of implementation and cost no more than a pure Analog Control System for one control concept. There would be no increase for a Direct Digital Control with Manual Backup System if the control concept were changed, while there could be considerable additional cost with an Analog System, if the control concept were changed.

Jan 1, 1975

By Chuck R. McLendon

A new face ventilation system was needed at the Allied Chemical Trona mine, near Green River, Wyoming. The development of an exhaust manifold face ventilation system came from a need to reduce the dust and noise concentration level while maintaining methane control at the continuous miner working face. Dust laden air from a heading being driven by a continuous miner was contaminating the intake air in the mine around the roof bolter operator and adjacent headings. Each working heading was exhausted into the last open crosscut by a face fan. A face fan would contaminate the adjacent downstream heading with dust-laden air until a high dust concentration developed in the final entry before the returns. A face ventilation system was needed to give the exhaust of each heading an individual path to the return air. In addition, the system could not interfere with the present room and pillar mining process. A manifold system of rigid duct ventilation tubing was designed using the existing fans in a parallel arrangement. Each system was to consist of the rigid duct tubing in three headings junctioned together at the last open crosscut and exhausted at a common branch in the return air. Each heading was to have its own damper (or valve) so that air could be directed where it was most needed. The system was installed using both round and oval rigid duct ventilation tubing to minimize head loss and to allow proper ground clearance for mining machinery. Two fans in parallel were used to exhaust three headings. By adjusting the valves at each heading, up to 18.0 kcfm (9.36 cu m per sec) could be exhausted from one heading and still keep the methane level controlled in the other two headings. The manifold exhaust system has proven to be an efficient, long lasting ventilation system at the Alchem Mine. It has reduced the dust and noise exposure levels at the working faces while keeping the methane level under control.

Jan 1, 1980

By Donald J. Worth

When Eugene Bailey asked me to contribute to this session on "Canadian exploration - 1976", it took a little coaxing before he got me to agree. My immediate reaction was, what could i say about Canadian exploration that already had not been said a hundred times in the past few years; secondly, why include a banking person in such a discussion? Everyone knows banks only come into the picture after the discovery has been made and feasibility well established and validated. Rather than wrestle with these misgivings, I decided to take the easy way out and go on blind faith in Eugene - that is, he asked me so he must think that I could come up with some useful thoughts and at least touch upon some of the pros and cons of exploration in Canada. The object of the whole exploration exercise is to Find economic deposits, once they are found, one cannot really move them elsewhere to mine them. It follows, therefore, that we should really be speaking about the pros and cons of mining In Canada and my treatise will eventually lean in this direction. In any event and before getting down to the pros and cons, let us take a quick look at the history of mineral resource development in our country since the end of world war II. At that time, we were producing well under one billion dollars worth of mineral products including hydrocarbons.

Jan 1, 1976

By T. W. Healy, M. S. Moignard

The use of electrokinetic or zeta-potential phenomena in studies of the properties of mineral sulphides has increased greatly over recent years. This review aims to examine and discuss the body of literature on the subject of electrokinetic properties of sulphides in a comprehensive and critical manner. Although the review covers the period from 1925 to 1975, it is only in the past ten years that researchers have been fully aware of the implications and problems of chemical reactions, notably oxidation and precipitation reactions, on the surface properties of sulphide minerals. These papers are discussed in more detail than the earlier publications. A table containing a list of determinations of iso-electric- points and points-of-zero-charge of mineral sulphides, and the methods employed in obtaining these results, is presented.

Jan 1, 1976

By V. N. Kolesnikov

The Sikhote-Alin part of the Circum-Pacific Ore Belt is characterized by wide distribution of Sn, Pb, Zn, W; Au, Ag, and other mineralization. This mineralization is regionally associated with the Late Cretaceous-Tertiary East Sikhote-Alin volcanic belt where it overlaps the Taukha accretiollary-wedge terrane of the Early Cretaceous age. The Pb-Zn deposits of the Dalnegorsk ore district may be grouped into the skarn (about 80%) and vein types. The skarn deposits are of major commercial value. Their geological position is controlled by the carbonate units located within tectonic melange of the Taukha terrane. Some other lithological and tectonic factors also play a significant role ill distribution of the mineralization. The ore bodies are traced to the depth of 1000-1500 m below the surface, having a pipe-lens shape and vertical zonation. Major minerals of the ores are galena, sphalerite, pyrrhotine, chalkopyrite, hedenbergite, quartz, and calcite. The minor elements of the Pb-Zn mineralization are cadmium, silver, bismuth, and copper. The paper describes relationships between mineral suites and minor element contents in the ores, as well as their significance for processing the ores. The metallurgy applied allows high recovering of the major components (Pb -93.9%; Zn -91.4%). However the tails contain some minor components that may be of commercial interest.

Jan 1, 1998

By W. M. Schafer

The risk that water quality will be degraded by mining activity can be evaluated using risk analysis techniques. Water quality impacts can occur where water-rock interactions with tailings, waste rock, or leached ore lead to increased loading of constituents into surface or groundwater. Constituent loads contributed by mining facilities are determined by the migration route and chemical evolution of mine water. Mass load contributions from mines can be determined by estimating the prototype pore water in contact with mining waste, predicting the rate and timing of flow, assessing the degree of geochemical attenuation, and modeling chemical mixing with natural surface or groundwater. Mining facility siting and design measures can alter the chemical evolution of mine water by varying the quantity or quality of flow. Stochastic risk management techniques provide a powerful tool for quantitatively identifying the environmental consequences of various siting and design alternatives.

Jan 1, 1998

By Grant Davis

An International Symposium on the Ecology and Revegetation of Drastically Disturbed Areas was held at the Pennsylvania State University in August 1969. Scientists from 13 foreign countries and 18 states in the United States attended this meeting, which focused on those areas disturbed by mining. The symposium enabled scientists from all over the world to get together for two weeks and discuss informally some of the knotty problems of reclaiming these disturbed areas. Trying to present the results of each of the 64 papers delivered at the symposium might be difficult. So, I will try to bring you up to date on the general status of research on the reclamation of surface-mined areas, particularly in revegetation and hydrology. I will also mention some research that is under way but was not presented at the symposium.

Jan 1, 1970

By S. J. Czehura

The Butte quartz monzonite is the host rock for early porphyry copper style mineralization and subsequent mesothermal-epithermal, enargite-gold style veining that transects the district. The east-west Anaconda system veins: including the Emma, Anaconda-Original, Syndicate, Badger-State, and Alice-Rainbow veins, each with strike lengths of over 12,000 feet and vertical continuity in excess of 4,500 feet, along with mining widths from 5 to 50 feet, are unique to Butte. The incredible dimensions and tenor of these veins have yet to be surpassed and Butte is still touted as being the “Richest Hill on Earth.” The Anaconda Company was formed in 1895 to develop underground copper reserves in the district and eventually consolidated all operations under one company. Production from underground mining continued through the mid-1970’s. Open pit mining in the Berkeley pit began in 1955 with the extraction of supergene ores, along with the remnants of deeper horsetail zones inaccessible to the underground mines. Operations in the Berkeley pit were suspended in mid-1982 because of the rejection of high arsenic, copper concentrates at major smelting facilities throughout the world. Bulk mining of porphyry style mineralization in the Continental pit began in January 1980 to supplement copper production while stripping “C” pushback in the Berkeley pit. The Anaconda Smelter closed in September 1980. A molybdenum circuit was added to the Butte Concentrator in 1981 and mining continued in the Continental pit to produce copper and molybdenum concentrates. A blend of Berkeley and Continental ores were processed to dilute penalty metals in the final concentrates marketed to toll smelters. All mining operations ceased mid-1983 when Anaconda closed the Continental pit and offered the property for sale. Montana Resources reopened the Continental pit in June 1986 to produce copper and molybdenum concentrates. Operations were suspended mid-2000, because of exorbitantly high power prices, but resumed in November 2003 with rising metal prices. Bulk open pit mining of the early porphyry style mineralization has sustained production over the past twenty years and mining is expected to continue in the Continental pit with favorable prices. Future mining will eventually develop a 500 million-ton geologic resource incorporated in a supergene enrichment blanket situated between the Berkeley pit and the Continental pit. Grades in this enrichment blanket range in the neighborhood of 0.5% copper.

Jan 1, 2006

By Michel L. Bilodeau

Mineral exploration is a sequential information gathering process. Primary exploration programs filter favorable areas through a series of geological, geochemical, and geophysical tests resulting in the discovery of mineral occurrences. The most favorable of these discoveries provides economic justification for a delineation drilling program. The purpose of delineation drilling is to provide information for estimating relevant physical characteristics of the mineral occurrence. These estimates are used to evaluate the exploration project and, eventually, the economics of mine development. Delineation drilling normally completes the exploration process. If the assessed economic characteristics of the delineated occurrence provide justification for mine development and production, an economic mineral deposit is the end result of the exploration process. Subsequently, a development drilling program is initiated to obtain the necessary data for detailed mine planning. The delineation drilling stage is in itself a sequential investment process. As delineation information accumulates, the reliability of geological estimates is improved and, thus, the uncertainty associated with the assessment of profitability criteria is reduced. Delineation drilling should continue as long as the marginal benefits, which result from improving the reliability of profitability criteria, exceed the marginal costs associated with the additional drilling.

Jan 1, 1979

By LeRoy Kienitz

There may be someone here who is not required to run his equipment at its maximum capacity. There may be some fortunate enough to have more crushers than needed, wider conveyor belts than required, and other mill equipment equally oversize. If so, then this paper will have no interest for him; but if most of you are in the situation we in the aggregate producing industry are in, then you probably wish to crowd your mill equipment to its limit. When you do this you must watch for block-up and overloads of all sorts. You need more eyes than you have to guard the critical points. The human eyes that now do nothing much, but watch should be freed for more productive work.

Jan 1, 1961

By Jon C. Yingling

A control system for reducing peak loads on mine conveyor networks is proposed. The system involves continuous monitoring of flows into the conveyor network and section feeders with variable discharge capability. The control strategy uses differences in material transit times from various production units to the transfer points in the network to forecast load levels that will be intersected by the discharge of the controlled feeders over future time intervals. Feeder setpoint adjustments are made to prevent excessive peaks in the combined flows at the transfer points, while maintaining adequate feeder throughflow to avoid production bottlenecks.

Jan 1, 1992

By A. F. MacDonald

The rugged foothills of the Allegheny Mountains in Washington County, Southwestern Pennsylvania, lend their terrain very well to the use of aerial tram systems to carry refuse from Bethlehem Mines' two preparation plants to disposal areas some distance from the plant site. Bethlehem Nines Corporation has three deep mines in this area, all of which are mining the Pittsburgh Coal Seam, The raw coal is prepared for metallurgical use in a preparation plant at each mine, Trio of these preparation plants, Mine No, 51, Ellsworth and Mine No. 58 Marianna, use aerial tram systems to dispose of reject material.

Jan 1, 1966

By John D. Grothe

Laboratory experiment as a basis of commercial plant design has been the subject of much analysis and thought and on which a large number of articles and papers have been published. We would be forced to choose between an unduly brief exposition if we wanted to cover it completely, or no exposition at all. We must therefore concentrate upon the essentials without ignoring at the same time too many of the qualifying factors which, by the choice of what we want to examine, may become side issues. In doing so, we do not imply that these side issues are therefore any the less important. In every case, what is said here applies with almost equal force to the pilot plant which may be necessary as it does to the commercial plant. In discussing a recent paper by Derek C. Shelton on the Santa. Barbara Mill in Chihuahua at a meeting of the Inst. of Mining & Metallurgy (London), D. J. Ottley said on the matter of relating laboratory results and small scale tests to full scale plant results that he would like' to draw the attention of members to the great difficulty of scaling up mineral dressing plants and processes. He felt that this was an important yet neglected subject which merited considerable fundamental scientific attention from mineral dressers and plant design engineers in particular. How much of this fundamental scientific attention has, as a matter of fact, been accorded to the subject, mainly by our sister profession, Chemical Engineering. The close similarity to chemical engineering problems that we meet, particularly in hydrometallurgical operations, suggests that Chemical Engineering publications offer a rich source of information and discussions of methods useful to us. We have only to think of pressure leaching, ion exchange, liquid-liquid extraction, precipitation and so on, all problems in chemical engineering unit processes or of the new Freeport Sulphur Nickel plant in Cuba or the Sherritt Gordon plant and many others.

Jan 1, 1960

By Donald D. Born

Mine No. 95 is located in Harrison County about 5 miles west of Shinnston, WV, with coal properties covering the northwest corner of Harrison County and the southwest corner of Marion County and with adequate Pittsburgh seam reserves to support the mine for many years. The mine was opened in 1967 and was planned, projected and operated as a room and pillar mine. It is located on a spur branch of the Baltimore and Ohio Railroad, has rail loading facilities and shipped by rail during its development stage. In 1972 it was converted to a mine mouth power station supplier and now transports coal by conveyor belt directly to the Harrison Power Station of Allegheny Power System. In 1971 the first longwall unit was installed in a selected area of the mine and immediately an orderly system of planning was developed to overcome the restrictions associated with longwall mining. The first was the development of the technique necessary for the plugging of abandoned oil and gas wells that existed in the area. With the assistance of the Morgan- town Energy Research Center of the Bureau of Mines, this restriction was overcome and thus opened a great potential for longwall mining in northern West Virginia. Other restrictions that had to be considered for longwall planning were dwellings and other improvements, snap top zones, water courses, and adequate bleeder systems, and the handling and treatment of mine drainage. In 1975 the second longwall unit was installed and soon therefore became a total longwall mine.

Jan 1, 1986

By Alfredo Valdivia, Hamed Nejad, Vincent Monaco, William Cao

"The East Side Access (ESA) CM005 Contract - Manhattan South Structures - consists of the installation of the waterproofing and final concrete lining for railroad tunnels, 3-Level Wye track turnout structures, segments of the Main Cavern Station, and a series of Ventilation Structures excavated beneath the existing Metro North Railroad (MNR) Grand Central Terminal. Several key team decisions made collectively by the Construction Manager (CM), Designer, and the Contractor has allowed the scheduled construction duration of 29 months to be maintained. These strategies include the use of alternate design and construction methods, including the use of pneumatically applied concrete lining and precast lining. This paper discusses these strategies, and illustrates how successful teamwork and cooperation during the execution of a large-scale construction project can lead to lowering costs, improving quality, and maintaining the overall project schedule. INTRODUCTION The East Side Access Project The Long Island Railroad (LIRR) currently transports commuters from Long Island into Manhattan, terminating at the already over congested Penn Station on the west side of Manhattan. Once completed, the ESA Project will provide LIRR commuters direct access to the east side of Manhattan underneath Grand Central Terminal. The ESA Project will help alleviate the congestion at Penn Station, which currently accommodate the NJ Transit, Amtrak, and LIRR lines; reduce travel time for LIRR passengers traveling to the east side of Manhattan and facilitate connections to the NYCT Subway System and Metro North Rail Road. The ESA Project includes building new tunnels and facilities under Manhattan and Queens. (See Figure 1).The Manhattan Alignment In the Manhattan segment of the ESA Project the excavation in hard rock of tunnels, cross passages, caverns and shafts has been completed by tunnel boring machines, drill and blast, and road header. The construction of the structural concrete final lining, interior structures and fit-out of the previously excavated caverns and tunnels are currently being performed under Contract CM005 Manhattan South Structures awarded to Michels Corporation and Contract CM006 Manhattan North Structures awarded to Frontier Kemper Constructors Inc. This paper focuses on the design and construction aspects of Contract CM005 which is the first ESA Contract in Manhattan to successfully construct concrete final linings in pre-existing excavated areas."

Jan 1, 2016

By Neal P. Cochran

The Office of Coal Research Program has been outlined in our Annual Report for a number of years and reported on by various members of the OCR staff as well as by our contractors. The program is national in scope and is intended to develop new and improved uses for our Nation's coal resources and to maintain coal in a favorable economic position, vis-a-vis, the other energy forms. A program has been developed that includes conversion of coal to gas, gasoline and other petroleum-type products, and to electricity. These projects are only one facet of the OCR program albeit an important one. In many of the conversion projects we have underway, original development work has been done with bituminous and sub-bituminous coal. It is the intention of this paper to present a general outline as to how lignite might fit into one or more of these projects as a raw material. Our national lignite reserves are vast in scope and this has been recognized in the OCR program by development of a project specifically for lignite and by including lignite as a test raw material in many other projects. Project Lignite is intended to develop the Cop Acceptor Process for conversion of lignite to a high B.t.u. gas. In this effort we have included the design, construction, and operation of a lignite gasification plant at Rapid City, South Dakota. The work is being conducted by the Consolidation Coal Company and is an outgrowth of their laboratory development of this process. The first portion of our effort included a detailed economic study of a somewhat arbitrary grouping of States designated Market Area A that could be expected to use gas manufactured in a lignite gasification plant. The area included the Dakotas, Minnesota, Nebraska, and Iowa. This geographical area could readily be served if a process could be developed for converting North Dakota's lignite reserves, estimated at 351 billion tons, to high B.t.u. gas. Our study showed that Market Area A had a potential commercial- industrial market of one trillion cubic feet of gas a year. To meet this demand, we believe that part of the load can be obtained from commercial lignite-to-gas plants. At the time of our original study, we concluded that gas could be delivered to the city gate in Market Area A at about 45¢. As a result of price escalation in the interim, our estimate today might be slightly higher, but not significantly so, since some parts of the process appear better today than they did at the time of the original projection.

Jan 1, 1968

By Russell W. Hunt

The cave man of ages past took his wife-and family from the cave pointing to a fire he had built and beating on his breast said, "Look what I have done". Today man is taking his family back to a cave saying, "Come enter in because of what I have done". At the close of World War II Germany said if they had gone underground one year earlier with more of their operations, the war could have lasted four years longer with perhaps much of Britain devastated. The protection of the home front no longer rests with the soldier in actual combat. The battle will be won at home with the most careful kind of protection against missiles. After Nagasaki-Hiroshima Sir Winston Churchill said in substance "Up to now the Almighty has mercifully withheld from man the knowledge of these terrible weapons of destruction."

Jan 1, 1959