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By Dr. Richard F. Coon, James D. Mavis

Risks and abatements associated with preliminary reconnaissance, plugging and filling, and maintenance of perched mine water pool are examined. This case history showed that the initial appeal of portal plugging was replaced by concern over potential environmental hazards when details of implementation were investigated.

Jan 1, 1992

By J. K. Wolski

This paper addresses the effects of using jet fans as booster fans in mine ventilation networks. A method was developed to determine the pressure generated by jet fans using the momentum theory. The influence of a reduction cone and other ventilation parameters on the jet fan pressure was analyzed. Verification experiments conducted in the Waldo Mine are described. Examples are given to demonstrate the conditions for the effective use of jet fans.

Jan 1, 1998

By J. M. Keating, R. L. Wiegel

Those processing plants which depend on flotation for their mineral separations are always looking for reagents which are cheaper, more selective or in some other way may provide improved economic performance. This paper describes the rationale for and some results from applying a statistically based approach to reagent testing in those flotation plants which still rely on experienced operators for manual flotation control.

Jan 1, 1986

By David E. Thompson, Wesley E. Stimpson

The Massachusetts Bay Transportation Authority (MBTA) Red Line Extension Northwest is currently in the early stages of construction. The 3.1 mile extension of the Red Line from the existing Harvard Square Station in Cambridge, Massachusetts to Alewife Brook Parkway in Cambridge, Massachusetts will include a large, near surface hard rock, rapid transit station chamber at Porter Square in Cambridge (Figure 1). [ ]

Jan 1, 1979

By Robert E. Haun

Retech's Plasma Arc Centrifugal Treatment (PACT) system is a thermal technology that uses heat generated by a plasma torch to treat hazardous waste containing metals and/or organics. Metal bearing solids and soil are melted by the process, and organic contaminants are thermally destroyed. The molten material forms a hard, glass-like leach resistant mass after cooling in a mold. This paper discusses plasma processing in general and presents some results of treating mineral processing wastes using the plasma arc centrifugal treatment process.

Jan 1, 1995

By W. A. Lawruk, L. J. Wilson, D. E. Stief

The Tower mill is a vertical stirred mill using steel balls or pebble grinding media. This device is designed for fine grinding at significant power savings when compared to conventional tumbling mills. This paper describes the machine and its operation, application, and performance for wet grinding.

Jan 1, 1988

By S. K. Kawatra

It has been observed in some mineral processing plants that grinding circuit efficiency varies seasonally, such as in some plants which are located in the northern U. S. and Canada and undergo large seasonal temperature changes, with the grinding circuit efficiency different between summer and winter. This indicates that the temperature of grinding circuit slurry has a noticeable effect on grinding performance. The effect has rarely been studied. To this end, an investigation to examine the effects of changing temperature on efficiency and determination of the mechanism responsible has been carried out. Plant investigations and laboratory experiments have been conducted in order to study hydrocyclones. It was demonstrated that under otherwise constant operating conditions, the d50(c), size decreased linearly with increasing temperature, while the shape of the reduced efficiency curve remained constant. This effect was determined to be due to changes in slurry viscosity with temperature.

Jan 1, 1988

By Sarah Vest, Richard Sherman, Leo Martin

In 1988 a major exploration program was undertaken to determine the characteristics of the rock and soil for a 7.6 m diameter sea outfall tunnel beneath Boston Harbor out into Massachusetts Bay. The diffuser discharge location had been mandated by the EPA to a 10 sq. km area of seafloor connected to the proposed Deer Island Treatment Facility by a 14.5 km tunnel corridor. Geophysical surveys, deep rock borings, and laboratory testing, provided the information for the conceptual design. The program identified the range in material types and parameters to prove feasibility of a TBM driven tunnel and to locate the optimum alignment and depth.

Jan 1, 1991

By V. N. Kazakidis

With increased levels of automation, capitalization, and empowerment of citizens, the traditional axis of labour versus capital or national government versus capital, upon which the allocation of benefits from a mining project was traditionally based, has shifted primarily to a capital versus community axis. In light of this paradigm shift, it is critical for the sustainability of mining that economic indicators be considered at the pre-feasibility, feasibility, and permitting stages of a project. Such indicators should emphasize the ?ripple effect? of the economic impact of a capital-intensive mining investment on a region due to outsourcing, as well as the diversified spin-off opportunities and the technological advances that can be exploited by local communities.

Jan 1, 2003

By Michael W. Glasson, Archie M. Richardson, Leo Gilbride, Laine Adair

Andalex Resources, Inc. recently engaged in a ventilation planning exercise that resulted in the construction of a new main fan installation to support longwall coal mining at the Aberdeen Mine. This paper documents the planning process, including underground measurements, modeling, permitting, and construction of the new fan installation.

Jan 1, 1997

By Daniel A. Wasson

A review of the history of boosters is given with examples of the prominent types that have been made commercially. The performance and design features of protected core boosters are discussed in detail. A new gel booster is discussed with its advantages to the mining industry. Booster size, hole configuration, performance and safety aspects are reviewed. Important features of boostering in above ground and underground blasting are related to an economic analysis. This presentation will cover different types of boosters commonly used in mining. However, for the purpose of this paper a few terms need to be defined to clarify the action of different parts of a priming system. Booster* - "Any unit of explosive or blasting agent to be used in a charged hole for the purpose of perpetuating or intensifying the initial detonation". Primer* - "A unit, package or cartridge' of explosives containing a detonator or detonating cord which is used to transmit detonation to other explosives or blasting agents". Detonator - A device for initiating a detonation from a flame or a small electric current, the former being represented by a fuse cap and the latter an electric blasting cap.

Jan 1, 1981

By Robert F. Droullard

The U. S. Bureau of Mines (USBM) has investigated instrumentation and methods for measuring exposure to radon daughters in underground mine atmospheres. Both personal and area monitors have been studied through in-house and contract research. A field study in uranium mines identified some reliability problems that required additional work for the personal dosimeter systems. Improved versions of continuous working level detectors have been developed and tested for use as area monitors in underground mines. Test results for the personal and area monitors were satisfactory for underground mine applications.

Jan 1, 1981

By A. L. Wilder

Coeur d'Alene Mines Corporation's newest precious metals property is located in the old Rochester Mining District approximately twenty-five miles northeast of Lovelock, Nevada. Built at an elevation in excess of 6 000 feet, the Coeur-Rochester gold silver heap leach property encountered cold weather operational problems typical of most northern Nevada heap leach properties, soon after the start-up of operations last fall. Due to the size of the heap area under leach at Rochester, it was decided that 1 the usual practice of spraying to an "ice field" and waiting for the spring thaw was impractical. Further, the delivery schedule for a solution heating system of the size required was unacceptable. Accordingly, Rochester personnel embarked on a program to seek out a leach solution distribution system that would enable an operation through the winter and yet be cost effective. The findings of this program were rather dramatic and, as a result, the whole perception of heap leach solution application at Rochester has changed forever.

Jan 1, 1988

By Young C. Kim

Use of geostatistics to solve mining problems is gaining importance as the cost of developing new mines is increasing and there is a need to mine more marginal deposits. But, until recently, coal companies have shown little or no interest in geostatistics. However, the stringent quality controls on coal burning has led to a surge in interest in improved methods for estimating clean coal characteristics. Until now, most of the geostatistical applications have centered on the problems of estimating in-situ coal characteristics (Sabourin, 1975; Wood, 1976, 1979; Fang and Stark, 1976; Pauncz and Nixon, 1979; and Knudsen et al., 1980). Little work has been done in applying geostatistics to coal washability, except that by Armstrong (1980). Applying geostatistics to coal washability basically means the estimation of cleaned coal characteristics, with the aid of geostatistics. Cleaned coal estimation plays a very important role in overall emission control strategy, as can be seen by the general flow diagram of such a strategy shown in Figure 1. The scope of this paper is limited to one aspect of the overall emission control strategy shown in Figure 1; namely, the prediction of cleaned coal characteristics using geostatistics.

Jan 1, 1982

By W. S. Fyfe, G. Southam, T. J. Beveridge

Sporosarcina ureae was able to grow in the presence of tip to 10-ppm L-asparagine complexed gold. However, 10 ppm Au3+ was found to be highly toxic to Sporosarcina ureae, killing 109 bacteria/mL within a few seconds. To compare the effects of these responses on gold mobility, an in vitro bacterial biofilm model was developed to examine the interaction be¬tween Sporosarcina ureae and ionic gold or L-asparagine gold complexes in gravity fed columns. The immobilization of ionic gold was between 80% and 90% over a period of one week. But, as the available cellular reactive sites became saturated, immobilization decreased to 14% within two weeks. In the L¬asparagine-gold system, gold immobilization in the cytoplasm occurred at a high rate (80% to 90%) throughout the experi¬ment, with limited toxicity towards Sporosarcina ureae. The bacterial immobilization and detoxification of L-asparagine¬complexed ionic gold was associated with a low molecular weight, i.e, <5,000 dalton (atomic mass unit), intracellular protein fraction. This peptide-complexed gold would allow for the continued biogeochemical cycling of gold under ambient (<100°C) surface or near-surface conditions.

Jan 1, 2000

By Dale R. Andrus

Why is there such an increased thrust toward positive multiple use land management and where will it lead? History and purpose of the mining law of 1872. John Marshall discovered gold at Sutter?s mill near Coloma, California, on January 19, 1848, and utter chaos resulted. The great migration of people to the undeveloped western lands had begun. Prior to this discovery, copper, lead, and iron had been the minerals for which the laws were made. With this discovery of gold on the public domain, it became apparent that congressional legislation was necessary. This became even more apparent as each of the numerous mining districts which were springing up in California, and elsewhere in the west adopted local miners&apos; customs to regulate their activities. Although these early miners acted under mining district rules and in some cases state regulations, they were, in reality, appropriating minerals without sanction of federal law.

Jan 1, 1970

By W. A. Rickelton

Trialkylphosphine sulphides, in contrast to their well known oxide analogues (1,2,3,4), have received comparatively little attention as metal extractants and previous studies have been biased toward analytical rather than commercial solvent extraction applications (5,6,7). The sulphides are soft Lewis bases and only from complexes readily with the limited number of metals in the periodic table which can be classified as soft acids (8) e.g. Ag+, Hg2+ and Pd2+. Consequently, these compounds tend to be more selective than the broad-spectrum, hard-base, phosphine oxide extractants such-as TOPO (trioctylphosphine oxide). The purpose of this paper is to describe a potential application of one phosphine sulphide, CYANEX® 471X extractant, in the selective recovery of silver from base metal sulphate solutions. CYANEX 471X is triisobutylphosphine sulphide (TIBPS).

Jan 1, 1984

By Frank A. Jerabek

Pneumatic stowing was first introduced in longwall mining in the middle twenties. Since that time it has advanced through many stages of development, particularly abroad, which have greatly improved its efficiency and contributed to its growing use. Pneumatic stowing originated in coal mining but has also been adopted in metal mining. This paper discusses the techniques of pneumatic conveying of. stowing material and equipment and applications of pneumatic stowing.

Jan 1, 1966

By William E. Wallace, Larry Grayson, Thomas Simonyi, Joel C. Harrison

Application of an SEM-based methodology suggests a reason for past contradictory results on the relationship between quartz and coal workers&apos; pneumoconiosis (CWP). Results indicate that coal seams with the same bulk analysis of quartz have different amounts of surface-available quartz. Our research shows that the amounts of pure and surface-available quartz in a respirable dust vary directly with the rank of a coal seam, except in the case where rock materials are mined. The estimated amount of surface- available quartz therefore provides a measure of the quartz-related fibrogenic potential of a respirable dust.

Jan 1, 1992

By A. K. Sheik, W. G. Pariseau

A small underground mine in northern Idaho was used as an experimental facility for studying the role of water in the analysis of mine opening stability. Laboratory test data, borehole measurements and geological mapping assisted in constructing a coupled finite element model of the rock mass. The model was used to make quantitative estimates of: 1) rock stress, strain and displacement changes, and 2) water pressure and flow velocity changes that occurred during historical mining. Stope cuts and wet fills were included in the analysis. Stability of crown pillars between stopes was of particular interest. The relatively low effective stress and high rock mass strength showed that water pressure changes were of no great consequence in agreement with experience. The computational tools used in the analysis may be applied to other wet mines with appropriate changes to site-specific input data.

Jan 1, 1999