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By Jeffery L. Kohler

A method of monitoring production, information, i.e., raw tonnage and machine state, from each working section has been developed. The method is based on the sensing of electrical parameters in each section load center, and the reporting of this information through the existing mine-wide monitoring system. A decision-theoretic type of pattern classification technique has been used to define the machine states. The basis of the method is presented in this paper, along with a proposed hardware and software implementation scheme. Information issues central to the development and use of the proposed production monitoring system are also discussed.

Jan 1, 1988

By A. B. Samaddar

A prototype automated mapping and spatial information management system has been developed, and illustrates how a powerful map manipulation capability and a comprehensive display system can be combined using both raster and vector mapping: The concept of a mapbase and information retrieval mechanism, query language as well as text and graphical menus, is introduced. The Geographic Information System (GIS), which has been built around a system for storage and retrieval of spatial and textual data, allows interaction with geographic space represented on a displayed map. The prototype is demonstrated using maps and information of an open pit mine.

Jan 1, 1989

By J. C. Yingling, R. Kumar, J. Sottile

The capability for on-line measurement of the quality characteristics of conveyed coal now enables mine operators to take advantage of the inherent heterogeneity of those streams and split them into wash and no-wash stocks. Relative to processing the entire stream, this reduces the amount of coal that must be washed at the mine and, thereby reducing processing costs, recovery losses and refuse-genera¬tion levels. In this paper, new ap¬proaches for optimal control of the segregation process using time-se¬ries models and empirical distribu¬tions are presented and demon¬strated using field data.

Jan 1, 2000

By Peri Mehling, Allister Brown

Environmental regulations concerning the processing of gold ores and the treatment and disposal of spent process solutions range from rigid standards in some locations to site specific options in several other jurisdictions. This paper examines the regulations and policies in two North American jurisdictions. Emphasis will be placed on the mill process and waste stream treatment and disposal, and implications for environmental impacts. Case examples of mine licence requirements will be discussed, with brief descriptions of individual treatment and disposal systems. Policies and environ- mental regulations within each jurisdiction will be examined in terms of potential environmental protection.

Jan 1, 1987

By Y. T. John Kwong

Modified after procedures for assessing acid-generating potential of coal spoils, most acid-base-accounting (ABA) analyses inadequately characterize highly varied metal deposits. Although mineralogy critically controls acid generation and metal leaching, acquisition of appropriate data and their interpretation are poorly developed. Metal loading rates are commonly determined by kinetic testing, which rarely duplicate actual field samples and conditions. Accurate predictions and reduced assessment costs can conceivably be achieved by (i) use of geochemical analyses to define surrogate indicators; (ii) intelligent acquisition and use of mineralogical data; and, (iii) compilation of geo-environmental ore-deposit models to validate inference based on detailed geology.

Jan 1, 2000

By Stephen G. Whittaker, Rosalind A. Schoof, Martha J. Steele

In determining remedial action objectives for metals in soils, the U.S. Environmental Protection Agency typically assumes that the metal concentrations in house dust are the same as the metal concentrations in soil. Data now available from several studies that were conducted in mining communities suggest that for some metals, concentrations in house dust may be lower than those in soil. This paper reviews available data on the relative soil and indoor dust concentrations of arsenic and cadmium and examines how changing assumptions regarding indoor dust concentrations of arsenic affects risk assessments and determination of cleanup levels.

Jan 1, 1992

By J. Stachurski, N. A. Abdel-Khalek

Flotation tests were carried out on six coal samples of different rank as well as their oxidized samples. A mixture of diesel oil and alcohols was used in these tests. Surface oxidation caused a distinct decrease during flotation recovery with some improvement in the grade. The reduction in the recovery increased with increasing concentration of the oxidizing agent. The floatability of low rank coals was affected by oxidation to a higher degree than the floatability of medium and high rank coals. The recovery-size curves of oxidized samples were similar in shape to the recovery-size curves of non-oxidized coals.

Jan 1, 1991

By Liang Ruilu, Guo Lihua

In light of the properties on process mineralogy of the old tailings in a certain copper mine in the People's Republic of China, a new process of combined reagent and stepwise flotation is applied in which the flotation of copper sulfides is followed by the flotation of copper oxides. Recoveries of copper and associated gold and silver have been greatly increased. The tailings obtained were subjected to the gravitational separation-magnetic separation process to recover iron minerals. Tailings from iron separation are taken as fillers and sent to the pit underground. Thus, the secondary resources are comprehensively utilized.

Jan 1, 1995

By P. Lausch, R. A. Mercer, J. F. Archibald

An innovative, polyurethane-based, spray on rock-lining material, designated Mineguard™ by its developers, is being manufactured to provide rapidly deployable area support coverage for specific use in underground hardrock mines. This form of surface-coating agent is intended to replace both shotcrete and the screen component of bolt-and-screen support systems. Due to the rapid rate of application, ease of installation and ability to achieve a 90% cure within seconds of application, Mineguard™ has considerable potential for use in mining and excavation operations that require a rapid rate of advance and a high degree of automation.

Jan 1, 1996

By O. E. Etheridge Jr., R. A. Lowe, C. I. Basilio, J. M. Randolph, S. W. Sheppard

The low-shear viscosity of kaolin slurries is one of the principal characteristics that determine whether a clay can be utilized for paper and ceramic applications. In this work, the causes of high low-shear viscosity and methods for improving the rheological behavior of the slurries were investigated. The presence of fine-grained smectite impurities within the kaolin was shown to detrimentally affect the low-shear rheology of the slurries produced from these clays. It was also shown that mechanically working (i.e., pugging) a crude kaolin followed by desliming to remove these impurities can reduce the low-shear viscosity.

Jan 1, 2000

By S. K. Kawatra, T. C. Eisele

A horizontal-baffle arrangement has been developed to prevent excessive axial mixing in flotation columns. These baffles have been shown in previous work to improve the grade/recovery performance of both a laboratory-scale column and a pilot-scale column (Kawatra and Eisele. 1993). In this paper, results are given for continuous on-line operation of the pilot-scale baffled column in a commercial coal- cleaning plant. These results show its ability to operate for extended periods without plugging, to produce a consistent-quality product even while the feed quality was fluctuating, and to remove much of the pyritic sulfur from the coal.

Jan 1, 1995

By Guerry H. McCullen, Bruno Despujol

Quartz and phosphate grains from concentrates and ores from Atlantic Coastal Plain sediments often are wholly or partially coated by humates. Coatings were studied in situ using infrared microscopy, by transmission Fourier transform infrared of extracts, and scanning electron microscopy. The 14C age of the coatings is about 20,000 years, much younger than the mineral substrates. Coatings on double flotation concentrates indicate that the conditioning pH may be too low, allowing coated quartz grains to follow phosphate grains through beneficiation. Organic matter from coatings may contribute to processing problems as well as affect final product quality.

Jan 1, 1999

By C. D. Hebert, T. Gregor, M. Ghazi, G. J. E. Kramer

This paper describes the recent application of gasketed, precast concrete segmental lining design that has improved tunneling productivity and quality. The speci?c segment arrangement includes: six-piece ring with equal 60 degree gasketed segments, juxtaposed key and counter-key segments, trapezoidal and parallelogram shaped segments, inclined and skewed radial joints and plastic circumferential joint connectors. This allows rapid, but accurate ring erection, reducing mine cycle times. The design avoids cruciform joints, minimizes potential gasket damage and eliminates the need for separate left and right ring molds. The implementation on the Los Angeles ECIS and NEIS sewer projects is described.

Jan 1, 2003

By St. Mergentime, K. Zeidler, V. Gall

2001, the New Jersey Transit Authority commissioned the JV Merco-Obayashi with the rehabilitation contract of the approximately 130-year-old, 4,200 ft long, partially brick- lined Bergen North Tunnel. The contract entailed the tunnel enlargement, shotcrete and rock dowels initial support according to the NATM, a waterproofing system, tunnel drainage and a cast-in-place concrete lining. The rock conditions encountered required design adaptations and significant modifications of the initial tunnel support. Flexibility, skill and extensive experience on the Authority’s and Contractor’s side finally lead to a success. This paper describes the operations and design modifications carried out.

Jan 1, 2003

By Patrick Doig, Ross Webb

The Bradshaw Section 5A Interceptor involves the construction of two miles of 108-inch, finished diameter tunnel in dry soils. Excavation is generally by Lovat TBM with ribs and lagging support. The tunnel is beneath a recreational parkway and stringent measures have been enacted to preserve the parkway and minimize disruption to the neighborhood. Apart from these constraints, the project would have been unremarkable but for the intervention of CalOSHA and the local fire department who ordered extraordinary fire protection measures. The paper discusses the cause and effect of these measures and comments on the potential repercussions for other projects.

Jan 1, 1999

By F. Chase, D. Pappas

Pillar recovery has been associated with nearly one third of roof fall fatalities in underground coal mines during the past decade. Safe pillar recovery requires global stability and local stability. Global stability is addressed primarily through pillar design. The local stability risk factors include cut sequence, the final pillar stump, supplemental supports (timbers vs. Mobile Roof Supports (MRS)), roof bolting, and many others. The National Institute for Occupational Safety and Health (NIOSH) has evaluated each of these factors through field research and analysis of accident statistics. The paper discusses design methods and technologies that have been transferred to the mining community and implemented.

Jan 1, 2003

By S. K. Mukherjee, A. W. Laurito, M. M. Singh, N. I. Jayaraman

This paper describes the application of foam to control respirable dust in a double-drum longwall mining section. The feasibility of injecting an adequate quantity of foam through the shearer drum was initially established in the laboratory. Thereafter, underground testing of the foam system to determine its effectiveness on an active operating longwall was conducted in a mine in West Virginia. The foam system proved superior to the water spray system. The details of the laboratory and field investigations, the results obtained, and the degree of acceptance of this system by the mining company are discussed in this paper.

Jan 1, 1987

By John F. Papp

Chromite is used both as a metallic and nonmetallic mineral. Chromite ore is used as the source of chromium by the metals industry and is used, without chemical alteration, in the refractory and foundry industries. Chromite ore is also the source of chromium for the chemical industry. On average worldwide far more chromite ore is used by the metallurgical industry than by any other industry. Thus, although the primary purpose of this chapter is to describe the nonmetallic uses of chromite, the metallurgical uses must also be discussed in order to provide a complete description of this commodity.

Jan 1, 1994

By Richard H. Sailors

Data from full scale marked ball tests are used to demonstrate the effects of abrasion, corrosion, and impact on overall wear rate. The predominate wear mechanism need be identified before the optimum alloy can be chosen for the grinding media. Use of high chromium grinding media often results in increased mill efficiency due to shape retention. Thus, a benefit from energy savings can result as well as a reduction in wear rate. Converting from steel to east high chromium grinding media requires close association and cooperation between producer and consumer in order to properly conduct these studies.

Jan 1, 1990

By J. Michael Howard

Holes cored through the Prairie Creek lamproite volcanic complex at the Crater of Diamonds State Park by companies interested in the site's commercial diamond potential give an opportunity to redefine the size and shape of the Prairie Creek pipe. Relationships of cored rock sequences and the discovery of a previously unrecognized major rock type allow a reinterpretation of the sequence and type of intrusive activity. Trench sampling of diamondiferous rock units yielded a diamond content far below what was anticipated based on an estimate from historical records. Inadequacies of shallow bulk-testing methods for a diamondiferous pipe are examined.

Jan 1, 1999