Search Documents

By J Edmund Hay, T S. Bajpayee

The Bureau of Mines is developing a test to determine the initiating strength of commercial detonators. Various tests of "detonator strength" are in use, but many of them do not correlate well with each other, and so far, there is little evidence that any of them correlates well with the ability of detonators to initiate detonation in an explosive. Therefore, the Bureau decided to attempt a measurement of the ability of detonators to initiate detonation. To this end, an explosive mixture of adjustable sensitivity was developed. This mixture was nitromethane sensitized with ethylene diamine, the sensitivity being "fine-tuned" by the addition of nitropropane.

Jan 1, 1992

By D. J. Adams, R. G. Gürtunca

In situ measurements and numerical modeling based on elastic theory showed that backfill stresses are considerably higher than originally thought. This has led to a change in understanding of rockmass behaviour. After describing previous work on the behaviour of the rockmass, this paper discusses possible reasons for the high stresses measured in backfil, and identifies the rockmass mechanisms possibly generating these stresses. It is concluded that the joints and the geological stratigraphy can lead to increased elastic convergence, and that the inelastic behaviour of the rockmass is also partly responsible for the increased closure measured in backfill. The use of an in situ modulus is suggested as an interim solution until a new computer model that allows for joints, different layers, and inelastic closures becomes available.

Jan 1, 1991

By Paolo Massacci, Marco de Nardis

SPL (Spent Pot Linings) are hazardous waste. The described work seeks to identify simple and inexpensive processes for recovering the recyclable materials and thereby both reduce the volume to be handed to the dumps and produce a waste that belongs to a less dangerous class. For this purpose a study was conducted to characterise the structure of the cell and the refilling elements at the end of the Aluminum process. The properties of the material that make up the SPLs were determined in order to apply the related selection procedures. The study permitted the design of treatment process able to reduce the negative environment impact of the aluminum production cycle.

Jan 1, 1995

By W. C. Smith

The U.S. Bureau of Mines examined previous research on rib stability in an effort to develop a practical approach to understanding, characterizing, and controlling weak rib conditions in underground coal mines. Because success in stabilizing ribs depends on a basic knowledge of how weak ribs behave, the report reviews the mechanics of rib failure and the relationship of coal mine geology and pillar constraint to rib instability. Strategies for choosing an effective method of rib support are considered, and various rib support methods are discussed. Finally, the report documents techniques for monitoring ribs and use of models to assess rib stability; such monitoring and modeling can also help determine the most effective method for roof support.

Jan 1, 1992

By M Lellis

During the last decades, maintenance has changed from an ordinary repair activity to a complex function that plays an essential role contributing for the companyÆs results. The increasing level of complexity of modern equipment motivates maintenance personnel to improve both techniques, and management systems, in order to face the new challenges. Managing properly those modern means of production requires knowledge of methods and planning systems, controlling and performing maintenance tasks, in such a way that two objectives are achieved at the same time: system efficiency and cost-effectiveness. This paper shows CVRDÆs experience on evolving and implementing a model to plan and manage maintenance activities in order to achieve a higher level of performance on its operations.

Jan 1, 2003

By Ribicic M, Kocar F

Surface lakes or water accumulation present a possible threat for the flooding of the underground mining works. Therefore, the criteria that define the conditions under which no flooding of the mining works can occur are of vital interest to the miners. The authors present the criteria that they developed for the Velenje lignite mine, Yugoslavia, and that take into account the elastoplastic behaviour of the rocks and the natural stresses involved in the deformable strata between the bottom of the lakes and the mine works as well as the extent of the direct caving-in process resulting from longwall mining activity. Fi- nally a generalization of these criteria to the other rock and stress conditions is discussed.

Jan 1, 1988

By Neil E. Izatt

The use of Molecular Recognition Technology (MRT), a selective separations technology using specifically designed ligands, has been established as an effective process for removal of metal ions found in many hydrometallurgical, chemical, and wastewater streams. The MRT process has been proven to be highly efficient and effective for indium extraction and recovery from zinc acid leach, electrolyte, chemical process and waste streams. A high percentage of the indium is recovered in a solid product format. MRT has also proven effective for germanium extraction and recovery from similar feed streams. This paper provides the indium and germanium metal recovery flow sheets and analytical results of the metal load and recovery steps.

Jan 1, 2006

By V. P. Keran, K. Leung

Two 32 foot x 14% foot, 6.4 MW autogenous mills have been installed in the Mount Isa Mines Copper Concentrator to replace the fine crushing plant, fine ore bin, rod mills and primary ball mills. This paper describes the reasons for the change, the rationale for the new circuit design and configuration, the design and scale-up processes used to size the mills, considerations for the installation of large mills inside an operating concentrator and some early operating data.

Jan 1, 1992

By B. Day, L. Elinson

There is general agreement among those involved in occupational and public health that work-related diseases are under-diagnosed and under-reported. Highmark is particularly well positioned to carry out industry health analysis as it provides medical insurance for approximately three quarters of the insured population of Western Pennsylvania including some of the areas largest employers. The purpose of this study is to gain a more accurate understanding of the mining industry rates of respiratory diseases that maybe occupationally related and identify those inflated respiratory disease and hearing loss rates. Conditions examined included COPD, asthma, and pneumoconiosis.

Jan 1, 2004

By Ross W. Smith, Xiapeng Zheng, Merrill P. Allen

The results of flotation of a primary desliming hydrosizer overflow material containing 14.6 wt.% P20, and 3.6 wt.% MgO are presented. The phosphate minerals were collophane and francolite and all minerals appeared to be liberated. The material had not been previously treated with flotation reagents. In the experimentation, various collectors were evaluated for effectiveness. The relative effectiveness of flotation in different flotation devices was determined. Finally a two-stage flotation scheme is proposed using column flotation of dolomite in the first stage and Denver cell flotation in the second.

Jan 1, 2002

Environmental and amenity factors have introduced a new dimension to the technical problems of the mining industry in finding, extracting and processing the mineral and energy products on which we all depend. Intervention by outside regulatory bodies is restricting the production of minerals and denying the industry access to large areas in which the orebodies of the future may occur. The solution lies to a large extent within the industry itself and appropriate management techniques are necessary to ensure that exploration and mining are seen as an acceptable as well as a necessary land use. Close liaison between operators and the responsible authority is necessary to achieve these objectives and to make the best use of our land resources.

Jan 1, 1979

By M. U. Özbay

A series of blasting experiments was carried out in an up-dip stope of a gold mine using short-perioddelay electric detonators. The main object of the investigation was to show the interactive effects of short-delay blasting. The delay range over which observations were made was restricted to between 10 and 200 ms. To quantify the blast results, data were collected on fragmentation, throw, position of muckpile, and ground vibration. For comparative purposes, blasting parameters for conventional pyrotechnic sequential firing were also measured. The paper describes the most relevant parts of the study and gives the experimental results. The interactive effects of short-delay blasting are analysed, and some aspects of the breaking mechanism are discussed.

Jan 1, 1985

By Rolf R. Schillinger

It is established to an increased extent that the basic questions about raw material extractions deal with water, dust, noise and vibrations. If it has not been definitely proven that these points won?t lead to excessive environmental strains, attempts at any explanations will meet with disapproval in advance. In order to answer the basic questions about dust, noise and vibrations quality management becomes most important, particularly with respect partly unavoidable emissions of production processes. The specific questions have to be answered within the context of good blasting practices, latest discoveries of the explosives industry, and by use of a Blasting Works Quality- Management, which includes both production quality and Risk-Management. The paper shows a practical way to work out a Quality-Management Program for companies involved in blasting activities.

Jan 1, 2002

By Smith G. A

The scope and complexity of the Melbourne Underground Rail Loop Project and the budget restraints on the planning, design and construction of the works necessitated sound manage- ment procedures for control and co-ordination. Project Management Procedures formulated by the Principal Consultant to the Authority, John Connell - Mott, Hay 9 Anderson, Hatch, Jacobs, ensured that the Authority retained overall control of the project at all times.

Jan 1, 1981

The impact of computers on the mining industry has increased for the past twenty years in most parts of the world. The application of computers in the mining industry has been demonstrated in areas such as geological data analysis, ore reserve estimation, mine planning, and manpower training. There is also a general concern in this country regarding the computing background of graduating mining engineers from the Australian higher institutions of learning. This paper describes specific steps which have been taken at the Department of Civil and Mining Engineering, The University of Wollongong to provide adequate computing background to mining engineering graduates. Specific topics discussed include hardware and software available to students and how "computers" have been integrated into the mining engineering course.

Jan 1, 1986

The history of the physical chemistry of steelmaking is reviewed through international conferences, and compared with the Japanese contribution. Subjects remaining to be solved are discussed. Several steelmaking technologies developed recently in Japan are surveyed.

Jan 1, 1980

By H. J. E. Hamel

Some aspects of the deformation behaviour and temperature rise during instantaneous compression loading of high purity aluminium By H. J. E. HAMEL The influence of deformation speed on the deformation behaviour of high purity aluminium was investigated. By varying the initial height-to-diameter ratio a considerable influence on the deformation behaviour could be noticed. Lubrication of the specimen end faces was found to have an influence on the flow behaviour and on the roughness of the specimen interface at pressing platens. The results of temperature measurements during deformation agree with work-hardening behaviour of the specimens. Flow curves calculated with the measured temperature rises do not agree with results obtained at lower strains by other workers. The possible reasons are discussed.

[1-Iron and Steel JOHN A. MATHEWS, Chairman RALPH H, SWEETSER, Vice-chairman WILLIAM CAMPBELL, Vice-chairman MAX ROESLER, Secretary Iron Ore CHARLES B. MURRAY, Chairman R. C, ALLEN W. 0, HOTCHKISS MAX ROESLER ERNEST F, BURCHARD WILLIAM KELLY DWIGHT E, WOODBRIDGE M. M, DUNCAN CHARLES F. RAND CARL ZAPFFE C, T, FAIRBAIRN THOMAS T, READ Blast Furnace WALTER MATHESIUS, Chairman WILLIAM H. BLAUVELT S. P, KINNEY C. SNELLING ROBINSON A. J. BOYNTON DORSEY A. LYON R. H. SWEETSER D. T. CROXTON RICHARD MCCAFFERY R. J, WYSOR THOMAS L, JOSEPH CHARLES P, PERIN]

Jan 1, 1928

By B. Jack, A. Vervoort

During pillar extraction, sidewall fracturing and spalling at some collieries constitute a severe stratacontrol problem. In order to obtain a better understanding of this phenomenon, a survey of pillar corner conditions before and during pillar extraction was conducted at one particular site. For the various successive mining steps, the vertical stresses on the pillar corners were calculated by use of a three-dimensional boundary element program. A significant correlation was found between the calculated vertical stress prior to the extraction of the panel and the sidewall conditions. During the extraction of the panel, a significant deterioration of the sidewall conditions at a pillar occurred only when the adjacent pillar was mined, causing an increase in vertical stress on the remaining pillar.

Jan 1, 1992

MINNEAPOLIS-HONEYWELL Regulator Co., and Trans-Weigh Co., have come up with a conveyor belt that thinks. The belt weighs material and then figures out the tons-per-hour that it carries. And you can't fool it by adding or subtracting material along the way. It makes allowances for any additional material as well as for any loss. The belt rides along a set of rollers. The force exerted on the rollers is transferred to a gage. The weight of the belt is subtracted electrically. Final measurements are fed into an electronic recorder which indicates the flow at the moment and the total amount which has been carried by the belt.

Jan 1, 1952