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By Ruth A. Maurer, Steven L. Capt. Van Drew

Coal preparation for a company having several sources of coal and several contracts for sale of coal was modeled. The objective was to minimize wash loss by selecting the quantity of coal to be supplied from each source and the appropriate washbox specific gravity setting to yield contract quality for a given shipment. constraints inposed by silo and stockpile sizes, plant and rehandling capacities, and varying coal quality specifications were included in the model. Solution is by iterative linear programming on an Apple II.

Jan 1, 1987

By C. Peppin, H. McLoren, D. Bayer

Hecla Mining Company and Master Builders Inc. conducted a study to evaluate the use of admixtures in reducing backfill binder concentrations. Additionally, admixtures were evaluated to help mitigate the occurrence of cold joints in the fill. Initial results demonstrated a 20% reduction of cement was possible while maintaining critical strength and flowability criteria. Admixtures also helped to control the formation of cold joints in backfilled areas.

Jan 1, 2001

By Michael D. Zuber

This paper discusses the use of a coalbed methane simulator that has been modified to account for the removal of grid blocks as a function of time to estimate gas emission and production for a variety of mine-associated problems. The specialized features of the simulator are presented. Example applications illustrate the models' use in estimating methane emission rates during mine roadway development, and estimation of longwall panel degasification by horizontal boreholes.

Jan 1, 1997

By R. Lai

This paper describes the application of a cyclonic flotation column (CFC) for coal cleaning. A CFC makes use of centrifugal force to create a density gradient in a column to augment the froth flotation process. In a CFC, a series of angular helical inserts is attached to the wall of a conventional column, and coal slurry is mixed with a series of impellers attached to a central shaft. The hydrophobic froth concentrates near the center shaft and moves upward, while the relatively heavy hydrophilic particles concentrate near the wall and are guided downward by the helical inserts. The results of pyritic sulfur removal from an Upper Freeport coal during CFC flotation are discussed.

Jan 1, 2003

By L. Alan Weakly

Coal mines and power plants utilize different methods to control dust for the safety of their workers and to protect their installations. The methods that they use are limited by the Environmental Protection Agency or the states in which they operate. Now there is a new technology for controlling dust at conveyor transfers! The Passive Enclosure Dust Control System utilizes several proven technologies to mitigate fugitive dust. This new system has been proven to be four times more effective than standard enclosures utilizing bag house collection and is considerably less expensive to install and operate.

Jan 1, 2000

By D. I. Phillips, P. J. Bethell

This paper focuses on the -1/2 mm cleaning at Elk Run Coal. The original circuitry incorporated desliming cyclones. Problems with slimes entrainment in the cyclone underflow (froth cell feed) resulted in poor froth cell selectivity. Laboratory test work led to the installation of high frequency desliming screens. Consequently, great improvement in cell performance was brought about by enhanced desliming with the ability to use split flotation. The modifications resulted in significant improvement in total plant performance and overall yield while maintaining clean coal quality.

Jan 1, 1987

By J. E. Chilton

Methanometers with catalytic heat- of-combustion sensors used in coal mines today will read low for flammable gases when oxygen (0,) concentrations are low or when methane (CH,) concentrations are greater than 10%. Thus, these methanometers may not be reliable during operations such as fire fighting or recovery of sealed mines. The U.S. Bureau of Mines developed a total flammable gas detector (TFGD) to measure CH, at concentrations up to 100% and to measure flammable gases in low 0, concentrations. This paper describes the operation and construction of the TFGD and discusses measurements of flammable mine gases obtained from a mine in western Pennsylvania.

Jan 1, 1992

The authors give a corrected form of the Korobov algorithm of optimal open pit determination and describe a method of optimising the mining sequence within a preliminary pit design. A method of automatically including roadways is also given.

Jan 1, 1992

By Daniel P. Coughlin, Robert C. Thomas, Christopher S. Romanek, Kristian W. Paul

Two separate constructed treatment wetland (CTW) systems receiving the same metal contaminated, acid sulfate water over different lengths of time and at different rates were evaluated for metal attenuation. Both wetlands are the alkalinity generator portion of a succesive alkalinity producing system (SAPS). Sequential extractions are employed to determine phases of metal removal. Results indicate that Fe, Al, Zn, Ni. and Cu accumulate in the organic substrate over time. Manganese accumulates initially, but is not retained in the system over time.

Jan 1, 2000

By Peter Keppler, Stephen D. Bundy

"Due diligence" is a review or audit of a facility or business to assess and quantify risks and operating status before an acquisition. Due diligence findings can be used to negotiate the price, general terms, and indemnification provisions in the purchase and sales agreement. In addition to assessing out- standing liabilities, necessary capital improvements, and the adequacy of operating budgets, due diligence should include "nontechnical" considerations, such as local community acceptance and relations, and the effect on the company's public image and operations. This paper will discuss how these considerations can be addressed in the due diligence process and factored into the transaction. Also, innovative means for risk reduction and risk transfer, during and after the transaction, will be discussed.

Jan 1, 2001

By P. K. Chatterjee

Before coal can be extracted from surface or underground mines, approval must be obtained from state and federal authorities. Permitting is the application process through which such approval is sought. The application includes en environmental impact statement Which focuses on Such topics as subsidence, toxicity of acid mine drainage, pollution levels of rivers and streams, post mining reclamation, and the effect on the hydrological balance of the area. The permitting procedure is extremely time and labor intensive, and requires extensive interdisciplinary knowledge. This paper examines a LISP based permitting procedure which will help to reduce the time taken to prepare and review a permit application.

Jan 1, 1986

By Tuncel M. Yegulalp

In this paper we revisit the well known "Ultimate Pit Limit Problem" and suggest an alternative approach for fast and efficient solution. We follow the approach originally proposed by Johnson and Barnes (1988), but utilize the "Excess Scaling Algorithm" in solving the equivalent maximum flow problem. This algorithm provides significant increases in speed and reduction in memory requirements over the well known Labeling Algorithm of Ford and Fulkerson (1956), enabling one to solve large problems with relatively small computers. We present results of a series: of benchmark tests using this approach against the well known Lerchs Grossman algorithm as well as a brief description of the new algorithm.

Jan 1, 1992

By David Jenkins

Grefco Inc. operates two diatomite mines in the western Santa Ynez Mountains. The larger of the two mines, the Palos Colorados Mine, is located approximately seven miles southeast of Lompoc. The Miguelito Mine is located about two miles south of Lompoc on the west side of the Miguelito Canyon. Diatomite from the Palos Colorados and Miguelito mines is trucked to the Grefco plant at Lompoc for processing (Figure 1). HISTORY Grefco, Inc. evolved from the originating Dicalite Company which in 1929 began operations at the Walteria plant in the Palos Verdes Hills south of Los Angeles. In 1942 Dicalite leased the Palos Colorados mine at Lompoc. In 1944 the Dicalite Company was purchased by Great Lakes Carbon Corporation.

Jan 1, 1995

By R. Asmatulu

A method of improving the efficiency of solid-liquid separation during centrifugal filtration has been developed. It consists of increasing the pressure drop across the filter cake using extraneous means such as pressurizing a filter chamber. This method, which may be referred to as hyperbaric centrifugation, is designed to increase filtration rate during the drainage cycle and, hence, to produce drier cake. In the present communication, the results obtained in a series of batch centrifugal filtration experiments are presented. The results obtained on fine coal and mineral samples show that cake moistures are approximately 50% lower than the case of using ambient pressure.

Jan 1, 2004

By Peter W. Harben, Edward M. Dickson

The distribution of metallurgical grade bauxite deposits will be discussed with the aid of a comprehensive table and a reference map. Information will include operating companies, mine locations, ore grade, and chemical analysis, geological environment, and production capacities. General comments will be made on the distribution of production and its relationship with major consuming regions. The pattern for the future will be assessed, including potential new producers, changing specifications and industry structure.

Jan 1, 1984

By J. J. Schwoebel

Resource Enterprises Inc. (REI) is exploiting the coalbed gas resource by working in unison with active underground mining operations. At REZ7s pilot project at the Soldier Canyon mine, Carbon County, UT, RE1 has drilled nearly 15.25 km (50,000 ft) of horizontal in-seam and slant boreholes during the initial two years of drilling activity. Produced gas has been sold to a natural gas transmission company on a continuous basis since mid 1983.

Jan 1, 1988

By H. F. Hennigar, D. L. Pawson, E. J. Foell

Results of an analysis of abyssal benthic megafauna based upon review of nearly 250 hours of videotape and 2149 bottom photographs are presented, and the utility and limitations of such analyses in deep sea biological studies are discussed. The images were acquired at depths of 4400-4800 m during a resource assessment cruise aboard the RV Prospector using a unique, deep-towed, television telemetry system coupled with 35-mm photography. The data review was carried out in support of NOAA efforts to provide adequate environmental baseline information before industrial exploitation of nodule deposits and concurrent monitoring begin.

Jan 1, 1991

By Carolyn S. Watkins, Thomas E. Ward, Debby F. Bruhn, Vern Winston, Mary Lou Rowland, Deborah K. Bulmer

The genetic characteristics of members of the genus Acidiphilium are poorly understood. As part of our study of the genetics of these bacteria, a search was made for an endogenous bacteriophage. Such a bacteriophage has been discovered. Several properties of the phage have been investigated. The phage has a lambdoid morphology and is somewhat larger than lambda. A variety of factors which affect phage stability have been investigated. The bacteriophage infects several of the strains that have been tested. Study of this bacteriophage should greatly increase our understanding of genetic mechanisms in Acidiphilium.

Jan 1, 1989

By Fernando A. Concha

There is confusion in naming the several models developed in Mineral Processing. We often hear of empirical, first principle, mechanistic and phenomenological models. The objective of this paper is to clarify and distinguish between these models, based on a philosophical and linguistic analysis. A state of the art review for mathematical modeling in Mineral Processing is also made.

Jan 1, 1995

By T. I. Probert, B. W. Burdett, L. B. Hales

Selecting a mineral processing control system from the multitude of offerings can be a formidable task. To assist the plant designer, the material in this chapter includes the advantages and disadvantages of different equipment types, configurations, and control strategies. Selection procedures are detailed, and the importance of each step in the design and selection process is explained.

Jan 1, 1986