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By F. P. de Kock, P. West-Sells, B. Wassink, D .. B. Dreisingerl

During the cyanide leaching of gold ores containing copper minerals, aurocyanide (Au(CN)f) is produced and typically recovered using activated carbon. However, free cyanide, as well as cyanide associated with cuprous cyanide complexes, are generally not recovered from the barren liquor. This results in a significant economic penalty in high cyanide consumption due to the dissolution of copper. 1\vo different configurations of a novel method for the treatment of barren liquor streams for cop­per recovery and cyanide recycle are described. Recovery of copper and cyanide is affected using solvent extraction (XI 7950). Loaded organic is stripped with a high copper, high caus­tic solution which is electrowon to produce copper metal. Depleted electrolyte is treated with sulfuric acid to recover cyanide which is returned to the leaching circuit. Results of benchscale and mini-pilot plant experiments are presented.

Jan 1, 1996

By Paul G. Greenhill

The Australian Mineral Industries Research Association (AMIRA) was established by the Australian mineral industry in 1959 to develop and manage collaboratively funded research projects. Owned and managed by industry, it coordinates research that answers questions defined by the sponsoring companies of the projects. Now over 35 years old, the Association is an excellent example of what can be achieved through collaborative research and an industry - backed research organisation.

Jan 1, 2000

By Moudgil. B. M.

The amount of hydrophobic materials constituting the mineral froth strongly influences the froth viscosity. Higher truth viscosity, on the other hand, can retard the drainage of physically carried over, hydrophobic particles. In phosphate flotation tests, a direct correlation was observed between froth viscosity and recovery, and an inverse correlation existed between froth viscosity and grade. Phosphate flotation tests in the presence of a silica depressant indicated that higher froth viscosity is an effect rather than a cause for the presence of silica particles in the froth.

Jan 1, 1994

By F. Grandjacques

INTRODUCTION Selective Reduction of Nickel in Oxidized Ores Oxidized nickel ores, either garnieritic or lateritic, contain much more iron than nickel. The regular carbon reduction in an electric furnace is operated in such a manner that the greater part of iron oxides is reduced simultaneously with nickel oxide, resulting in a low nickel content ferronickel. In order that the nickel content of residual slag may be suitably low, -excess carbon must be fed so that the carbon content of the ferronickel thus obtained is that of casting iron. The metal also contains other impurities such as silicon, chrome, etc. In order to convert the casting iron into slightly carburized ferronickel with high nickel content, the greater part of the carbon and more than half the iron contained therein must be oxidized by means of oxygen. Energy is thus consumed as carbon, and power to reduce iron oxides, and more energy is consumed as oxygen to re-oxidize the iron contained. This method can be economically adopted for nickel ores with grades ranging around 2. 5 to 370, but it gets excessively costly when nickel grade falls below these values. This is why, for nickel ores with low nickel grades and high iron content, studies were conducted to develop a selective reduction process which, while reducing only a small part of the iron oxide, would provide efficient reduction of nickel oxide. Rich ferronickel is thereby obtained, with nickel content ranging around 30 to 50%. Due to the presence of slag with a high iron oxide content, the metal thus

Jan 1, 1979

By Stephen Navin, Pablo Ferradas, Carlos Silvestri, Alexander Markov, Jon Kaneshiro

In the high Andes of Peru, two tunnels are being constructed totaling nine kilometers in length at an elevation of over 4,500 meters. The tunnels convey freezing and crystal-clear waters from rainfalls, streams, and lakes for the consumption of Lima. The drill and blast 3-meter wide by 4-meter high tunnels are being driven from both ends through folded and sheared volcanic tuff, andesite, agglomerate,and limestone, where groundwater inflow is high. This paper describes the design geological and groundwater inflow investigations and construction.

Jan 1, 1999

By M. Karmis

The Virginia Center for Coal and Energy Research is leading an interdisciplinary coalition to identify potential carbon sequestration sinks in unmineable coalseams as part of the U.S. Southeast Regional Carbon Sequestration Partnership. The Virginia Center for Coal and Energy Research and the Eastern Coal Council are leading education efforts for the project, as well as specific outreach efforts in Central Appalachia in order to develop a process for stakeholder education and engagement in sustainable energy.

Jan 1, 2007

By Haydn H. Murray

A hydrothermal bentonite located in the high Sierras in Nevada is being mined and processed to produce a natural dietary supplement. The minerals present are smectite, gypsum, jarosite, quartz, feldspar, kaolinite, goethite, hematite and zeolite. The clay material was analyzed for respirable crystalline silica, asbestiform minerals, heavy metals and dioxin. No asbestiform minerals are present and the crystalline silica, heavy metals and dioxin are all less than the maximums set by Federal and State agencies. The clay material was analyzed chemically for all major, minor, trace and rare earth elements. The geology, applications and analyses will be discussed in the paper.

Jan 1, 2005

By R. C. Beers, R. J. McKinley, R. D. Stewart

Preliminary test results at Occidental Research Corp.’s Irvine, CA, research facility indicate the viability of a new induced fluorescent sorting technique for preconcentration of limestone, coal, and oil shale. The patented “Oxylore”* process is a preconcentration stage that takes advantage of selective surface chemistry to label either ore or gangue particles with a fluorescent coating that can be detected by activation with ultraviolet light. The technology was originally developed by Ted Matthews (SME-AIME Fall Meeting, 1974, Preprint 74-B-328) and was acquired by Occidental in 1977. The firm has continued development of the process since its acquisition.

Jan 6, 1980

By R. Svensson

Mill linings play an important role in all comminution processes with tumbling mills. The selection of the lining profile and the lining material has a great impact on overall grinding cost and mill throughput. The cost of the lining itself is minor in comparison with media cost, energy cost and the value of the material produced in the mill. The total scope must be considered when mill linings are selected. This paper presents case stories and explains the technology behind: - Different lining profiles in rubber and steel. - Orebed magnetic lining. - Steel-cap rubber lining.

Jan 1, 1995

By William E. Souder, R. J. Evans

From time to time, major technological innovations arise that alter the time-honored ways of doing things. Such innovations can dramatically benefit society in terms of new products, increased outputs, reduced costs and general modernizations. However, the advent of these types of technologies is likely to be resisted because of their uncertain potentials, and because they disrupt established routines and industry patterns. This paper reviews the case history of water jet coal cutting, and assesses its potential to become a major innovation within the next decade.

Jan 1, 1983

By Richard Gertsch

In the operation of this mobile-modular system, inexpensive fiberglass charcoal columns are loaded with gold at strategically-located adsorption stations. The loaded columns are then shipped to a centralized stripping facility. After stripping, the columns are returned to the adsorption station. The advantages of this system are as follows: •Easy scale up from pilot plant to full production. •Low capital and operational costs. •Gold production quickly reacts to changes in ore production. •The solution circuits are simple and easy to maintain. •Charcoal damage is greatly reduced.

Jan 1, 1996

By R. Fernando

"The Office of Mine Safety and Health Research (NIOSH-OMSHR) currently is leading an effort in the development of the next-generation self-escape apparatus as part of the research imperative directed by the MINER Act of 2006. A multifaceted contract program over the past 3 years delivered key components and base breathing modules to form the basis for developing backpack and vest-style versions of dockable self-contained (closed-circuit) self-escape respirators with hoods (CCMERs). This paper outlines the current status in developing the CCMER that incorporates a docking and switch-over valve (DSOV) for seamless transfer from one breathing device to another, and a hood with an inner mask and speech diaphragm (HMC) for ease of donning, ease of use, and communication ability. Three versions of the CCMER are being pursued, namely: the CCMER-B, which can be worn as a backpack and incorporates the features of a miner’s belt; the CCMER-V, which is worn similar to a miner’s vest and attaches to a miner’s belt; and the CCMER-C, a breathing module cached along the escape route that can be docked to the -B and -V versions. Human factors considerations are a key element in the CCMER design, as it is to be continually worn by the miner while underground, and must be readily accessible for deployment when needed. The CCMERs are designed to be capable of being certified to 42 CFR part 84 standards, including sub-part O for mine use, and to meet MSHA permissibility regulations for use in underground mines. They are sized for sufficient oxygen capacities (Cap 2 and Cap 3 as defined in sub-part O) to yield a duration that is of practical use in a mine escape scenario. INTRODUCTION The National Institute for Occupational Safety and Health (NIOSH) Office of Mine Safety and Health Research (OMSHR) is leading the development of self-escape apparatuses to provide breathing gas to mining personnel operating in the event of an emergency in various capacities underground in environments containing hazardous gas components. The Mine Improvement and New Emergency Response Act of 2006 (also known as the MINER Act) and input from the mining community called for the need to move Self-Contained Self-Rescuer (SCSR) technology to a next-generation status. In response to this need, NIOSH’s Office of Mine Safety and Health Research (OMSHR) established a strategic plan to develop key components and devices with help from external experts knowledgeable in breathing apparatus designs. The US Navy was identified as a key expert in this field through its extensive experience in diving apparatus and life support systems, and development work commenced through Inter-Agency Agreements with OMSHR. A contracts program was also launched with industry experts specializing in this field. This paper outlines the current status in developing the Next-Generation Closed-Circuit Mine Escape Respirators (CCMERs) that could be used for surviving and escaping from a mine following an emergency that renders the mine atmosphere irrespirable."

Jan 1, 2016

By F. Mensah-Dwumah, W. H. Baker, G. W. Clough

INTRODUCTION The practice of injecting chemical grouts into permeable soils in order to stabilize them for tunnel construction is a common procedure in Great Britain, Europe and Japan. In this technique, the grout penetrates the soil in a fluid condition, but hardens or "sets-up" in about one hour due to a chemical reaction. As a result, the soil, is strengthened and made less pervious, and this, in turn, reduces ground surface movements, limits ground water flow, and controls movements of the heading during tunnel construction. It is only within the last five years or so that this technology has been used in the United States. Most of the applications have been involved in the work for the Washington Metropolitan Area Transit Authority (WMATA) subway construction. The experience gained from this work is, in many instances, unique and should serve to guide use of the grouting technology in future projects. This paper documents five WMATA case histories; information is provided as to the soil conditions, method of treatment, reason for treatment, and tunnel performance. Locations of the five projects covered by this study are indicated in Figure 1. All are within the boundaries of the District of Columbia and involve soft ground tunnel construction. Basic information for the case histories is given in Table 1. Tunnel sizes and depths below the ground surface as well as general soil conditions are similar in all instances. The tunnels are about six meters in diameter and are located so that the crown is five to ten m below the ground surface. The soils typically consist of alternating sand, clay and silty sand strata. However, soil stratification details are

Jan 1, 1979

By Ian McFeat-Smith, Robert J. Fowell

Roadheader machines have a specific place in modern tunnelling, not simply as a compromise between drill and blast techniques and full face machines, but as an economic and versatile form of mechanised tunnelling where the method of excavation is easily integrated with tunnelling operations. In the past, roadheaders have been subjected to misuses by engineers who failed to realise that, as in all mechanised tunnelling, a planned and systematic approach is essential if the full potential of these machines is to be gained. An increasing awareness of this, together with the introduction of the more powerful roadheader carrying their cutting potential into the hard range of rock is changing this situation and now makes the prospect of using roadheaders particularly attractive (1). The advantages gained by employing these machines can be considerable and Table 1 lists some of them. This table illustrates that from both cost, and installation points of view, the roadheader has considerable benefits over the full face machine. However, the principal advantage gained is in broken ground where heavy supports can be installed immediately at the tunnel face. In addition, access for planned maintenance and repairs to most working parts of the machine is at a premium and average machine utilisations of 40 - 60% can be expected. In comparison to drill and blast methods, up to 40% better progress can be regularly achieved, and the subsequent savings in overbreak costs alone would more than pay for the cost of a roadheader used to drive a 3km long tunnel. As with full face machines, ground disturbance is minimal and for short tunnels in urban areas a road-

Jan 1, 1979

By Peter D. Warwick

Recent investigations conducted by Federal, State, and industry organizations suggest that significant coalbed gas resources may exist in the Cretaceous and Paleocene-Eocene coal beds of the Gulf of Mexico Coastal Plain. Exploration efforts have focused on three areas which are in south Texas, north-central Louisiana, and south-central Mississippi (Figure 1). Coal-bed gas production is currently underway in south Texas and in north-central Louisiana. In Mississippi, several test wells have been drilled but no data are available on their production potential.

Jan 1, 2005

By Clifford O. Hamilton

In both mature and young maintenance workforces, the workforce commonly lacks some of the skills required for their assigned work. We call this the "skills gap." This skills gap usually exists in a new operation because although you may hire qualified maintenance personnel, they more often than not have little if any experience with the specific equipment at the facility. Performance Associates International, Inc., has developed and proven a technique to address the maintenance skills gap that is usually found in a new operation.

Jan 1, 2001

By F. Kennedy

Consolidation Coal Company (Consol) supports an active R&D effort to improve the safe, productive mining of coal and to utilize coal in an environmentally acceptable manner. Attention will be focused on degasification of coal seams, continuous coal transport systems, earth sciences activities, and coal combustion. Brief mention will be made regarding the SO2 emissions control programs. The research program constitutes about 1.0% of Consol coal sales which positions Consol as the preeminent coal company supporting broad-based research addressing the full spectrum of the various problems associated with utilizing the nation's abundant reserves of economical, readily available fuel.

Jan 1, 1989

By G. L. Mowrey

One critical element of the US Bureau of Mimes computer- assisted mining research program is the development of a reliable coal interface detection (CID) system. Several promising CID concepts currently being investigated by the Bureau include natural gamma radiation (NGR), vibration and passive infrared. To help establish which CID sensor technologies need to be developed for a given seam, coal and adjacent rock samples (immediate roof and floor) are being collected from selected major coal seams in the US and are being analyzed in terms of NGR and other geophysical measurements. This paper provides a brief overview of the Bureau's work in these CID areas.

Jan 1, 1992

By F. Wendling, G. M. Peixoto, J. A. M. Cano

A brief introduction is made on the existence of sulfides in the top gas of the Midrex Shaft Furnace, giving consideration to the operation of the furnace and the liberation of sulfur, as well as its consequential effects on the reduction process. The text shows a study of sulfur distribution in the pellet, emphasizing the importance of this distribution in relation to the liberation of sulfur during the reduction. A study was made to determine the sulfur compounds that exist in the pellets, showing ways of controlling the sulfur distribution and reducing its liberation during reduction.

Jan 1, 1991

By Leslie S. Rubin, John C. Roberge, Mackenzie Burnett

A self regulating helical inducer has been developed and tested for dry injection of coarse or fine solids into a hydraulic pipeline. This centrifugal pumping device has also been modified and tested for use as a boost pump in medium and long distance pipeline haulage systems. The helical inducer has been operated as an integral component of a slurry injection vehicle. This compact, low profile vehicle also includes crushing and screening components, solids feeding components, a track drive system for mobility and is run by a single operator. The helical injector and boost pump operate without speed and flow controls allowing for the practical hydraulic transport of excavated materials.

Jan 1, 1983