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By S. S. Klima, A. L. Mazzella, J. S. Driscoll, T. W. Beck

Previous testing was performed by researchers at the National Institute for Occupational Safety and Health (NIOSH) to improve longwall dust control using underside shield sprays with a longwall directional spray system. This testing provided encouraging results toward respirable dust exposure reductions for longwall personnel, achieving as high as 99% dust reduction at some sampling locations along the longwall personnel walkway. Additional laboratory testing was conducted to test these underside shield sprays in conjunction with a shearer-clearer spray system located on the longwall shearer body. The purpose of this testing was to determine if the underside shield sprays interacted positively or negatively with the shearerclearer sprays. Results from this testing indicate that while the shearerclearer system influences where the respirable dust particles are directed, underside shield sprays can still lower respirable dust exposure for longwall personnel.

Mar 2, 2022

Contents

Jan 1, 1985

By L. Alan Weakly

Page one is missing from book

Jan 1, 1982

By Stuart M. Jones, Eugene E. Hively

The Tower Mill is a vertical "stirred" ball/pebble mill recently Introduced In the Western Hemisphere This device offers a significant power savings on wet fine grinding applications when compared to conventional tumbling mills This paper describes the laboratory application of this mill In wet grinding hydrated alumina to products of 50 percent passing 2 to 6 microns

Jan 1, 1983

By M. Misra, I. Anazia

The effects of the enzyme, peroxidase, on the sedimentation and consolidation characteristics of Florida phosphate slimes were investigated. Results indicate that pretreatment with the enzyme was beneficial for slime dewatering and consolidation. Biological activity, resulting from slime pretreatment with the enzyme, induced higher mechanical binding between slime particles.

Jan 1, 1990

By Robert T. Tape, Thomas G. Harper

Valley-fill heap leaches built in steep terrain over low-friction angle liner system may be unstable even though analyses indicate stable ore slopes. This paper demonstrates the potential for massive heap failure using stability analyses which consider both heap slope and heap mass failure considerations. The computations presented also reveal the sensitivity of mass heap stability to liner friction angles.

Jan 1, 1987

By Roy H. Patten

When driving a shallow soft ground bore, the appearance of surface craters along the tunnel alinement indicates trouble, particularly when a major highway is intersected. During the excavation of a 3.7 m diam tunnel in Seattle, Washington a chemical grouting program was implemented to stabilize soil conditions sufficiently to allow advancement of the mole without loss of ground. Unanticipated mixed face conditions consisting of saturated running sand and some boulder pockets bedded on top of dense glacial till created excavation difficulties. A discussion of problems and corrective measures is presented.

Jan 1, 1987

By I. Andras

The paper deals with the application of artificial intelligence methods in assessing the effectiveness of longwall shield support. A fuzzy sets based method is used to derive response surfaces/curves representing the dependence between basic parameters of the shield, as the initial setting pressure and the stiffness on the response metric, i.e. the convergence and load increase during a working cycle.

Jan 1, 2008

By Janusz Cygankiewicz, Marian Branny, Józef Wactawik

The paper presents mathematical model of concealed fire. We consider a porous medium (goaf, coal fissures) through which air flows. The set of equations is constituted by transient, two dimensional mass, momentum and energy balance equations with sources describing oxygen loss and heat generation caused by coal oxidation. Paper presents several examples illustrating the phenomenon of spontaneous heating in goaf areas behind longwall faces.

Jan 1, 1997

By J. Dasher

Regarding the March 1991 ME technical paper by De Souza and Moore: For more than a decade since my February 1981 article on how to use modern metric, which SME-AIME had decided to do, I have monthly pointed out metric errors to the editors. In part, I do this because there has been no action to al low editors to fix figures and tables or to allow them to require authors to do so. The latest resulting atrocity provokes this discussion of vibrating drill handle units being stated in decibels.

Jan 1, 1991

By L. G. Austin

The data of Dunn and Martin (1978) is reanalyzed using a rigorous application of Hertzian theory to the impact process. The Young's modulus of steel required to fit their data to the theory is a factor of about 10 3, too low compared to the values quoted for steels. Thus, doubt is thrown on the validity of their experimental technique, and it is possible that their values for maximum impact force and stress are far too low.

Jan 1, 2002

By D. Farahmand

This paper focuses on formulating a practical procedure for forming long-range production and development schedules in underground mining. A computer program developed to be run on a microcomputer is presented and discussed in detail, and a practical case study is analyzed to demonstrate the suitability of the procedures discussed in the paper. The intent of the computer scheduling model is to have quick access to vital information when changes in development and production are under consideration by management.

Jan 1, 1986

By Dale C. Matthews

Pressure oxidation of refractory gold ores is becoming more popular in what has become an environmentally sensitive society. This article discusses some specific process problems and solutions involved with starting up and operating an autoclave circuit. The Getchell gold deposit is located about 72 km (45 miles) northeast of Winnemucca, NV. The deposit was discovered in 1934 and first production came about in 1938. The oxide portion of the ore body was mined and milled from about 1936 through 1950. Refractory arsenic-bearing sulfide ores had long been known to exist in the Getchell deposit. These ores had been mined concurrently with the oxides since 1938.

Jan 1, 1991

By Lynn B. Hales, Randy Ynchausti

Expert systems are now being used effectively to streamline and improve the performance of supervisory computer control strategies. Their advantages have led to use in both batch and continuous applications. Expert systems in the context of real-time process control, will be defined and examples of their successful implementation in autogenous, semi-autogenous and ball mill grinding circuits will be discussed.

Jan 1, 1990

By C. Villa Diniz, A. H. Martins, Fiona M. Doyle

It is proposed that battery grade MnO2 can be produced directly from a manganese ore from Azul Mine in Brazil, by leaching with HCI to remove heavy metals selectively. We are working to find a way of selectively separating Cu, Ni, Co, Pb and Fe from the resulting acidic manganese chloride solution, to detoxify it and produce marketable chloride solution. Chelating ion exchange resins are proving more promising for this separation than solvent extraction with commercially available reagents. Results from batch and column ion exchange tests that characterize the behavior of copper, nickel, cobalt, lead and iron are reported.

Jan 1, 1999

By J. S. Murty

In this paper, a report is given of studies undertaken in a laboratory rod mill to obtain the optimum conditions for the desired particle size distribution for long-distance transportation of coal through slurry pipelines.

Jan 1, 1987

By A. V. Glembotsky, N. A. Greshnova, V. P. Seregin, V. A. Glinkin

Based on a new alternative depressant of zinc sulphide - dimethyldithiocarbamate- modern technology has been developed for the treatment of complex polymetallic ores. In addition to its general function (depression of sphalerite and iron sulphides to some extent), this double-acting reagent is a promoter for galena and silver minerals. Laboratory and plant tests, as well as industrial experience have all shown consistently higher silver recovery to the lead concentrate as compared with sodium cyanide, resulting in less pollution and a safer environment

Jan 1, 1995

By T. Orgodol, P. Korpi

This paper describes the Boroo Gold Company (BGC) ore processing plant which is the first CIL/CIP plant in Mongolia. BGC is the first foreign investment in Mongolia since 1990 and follows the highest safety and environmental standards. Commissioning of the plant commenced in October 2003 and commercial production began in March 2004. Gold recovery is by gravity and conventional leaching and carbon adsorption. Detoxification of the leach tails is by the SO2/Air method before discharging the tails to the tailings pond. Ore types treated at Boroo are predominantly oxide with some transition ore as mining reaches the lower sulphide zone. There are several interesting technological issues and projects ongoing at Boroo which will also be discussed.

Jan 1, 2007

By Ian Kilgour

The development of the Escondida concentrator is described, from the design of the original 35,000 tpd concentrator through successive expansions and modifications to the 115,000 tpd plant currently under construction. Operating problems, and the steps taken to overcome them, are briefly discussed. Reasons for key equipment choices and flowsheets modifications in the expansions are explained, with some emphasis on the flotation circuit.

Jan 1, 1995

By R. Parkins

This paper will discuss a method used to refine the fill level, and orifice size for a dual motor conveyor drive with extended delay chamber fluid couplings. The subject conveyor is located on the surface at the Mountain Coal Company West Elk Mine, located near Somerset, co.

Jan 1, 1996