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By Walter C. Lorenz

In connection with its renewed study seeking solutions to problems created by release of acid water from bituminous coal mines, the Bureau of Mines recently surveyed reports already written on the subject. This publication is based on that search. The Problem Poor distribution of water is evident on an ordinary geographic map of the United States. The more abundant supplies of surface water appear to be centered in the northeast, the southeast, and the central humid areas of the country. It is in the midst of this abundant surface water, in the Ohio River Valley, that most of the bituminous coal is mined. Varied industry has located in the valley to use the coal and the river. The coal is a source of power and o raw material. The river provides transportation for raw and finished materials; equally important, it provides the water that is used for cooling and processing in manufacturing. It also serves as a vehicle for the disposal of waste.

Jan 1, 1962

By Albert L. Toenges

The State Division of Geology Arkansas Resources and Development Commission, and the Arkansas-Oklahoma Coal, Operators Association requested assistance from the Bureau of Mines in a study of coal-mining methods and practices in .Arkansas coal mines with the objective of reducing production costs. On October 7, 1946, a joint meeting was held by representatives of the Arkansas Resources and Development Commission, approximately 30 coal-mine Operators of the Arkansas -Oklahoma Coal Operaters Association, and representatives of the Bureau of Mines. The many problems confronting the coal industry in Arkansas, including mechanical mining in thin beds, costs, labor, and working time were discussed. Following this Meeting, a joint letter from Harold B. Foxhall, State geologist, and -P. R. Stewart, commissioner, Arkansas-Oklahoma Coal Operators Association, was addressed to Dr. R. R. Sayers; former ,Director of the Bureau of Mines, requesting that mining conditions in Arkansas be studied.

Jan 1, 1949

By Fernando Altamirano

Dado que en las unidades mineras existen problemas respecto al manejo de la información relacionada a la seguridad, salud e higiene tales como que los reportes enviados a las autoridades competentes (MEM, DGM, DGAA, OSINERG, DIGESA, etc.), se hacen en forma manual, generando una revisión y conteo previo tedioso y donde no existe una clasificación o estructuración de la información. En ese sentido, se plantea la utilización de las herramientas tecnológicas modernas para optimizar la administración de la información generada en las operaciones de forma diaria. Este sistema está desarrollado bajo una arquitectura Cliente/Servidor con bases de datos que soportan SQL., que se asegura una solidez en la generación de tablas relaciónales, un desarrollo práctico de las pantallas de entrada, flexibilidad para generar reportes y capacidad de expansión e integración a otras aplicaciones, donde se busca que el usuario se sienta a gusto utilizando su interfase full Windows diseñada para efectuar los registros y operaciones de manera intuitiva y versátil.

Aug 25, 2002

By A Maldonado, A Robert, K G. Mercer

The Hamersley Group in the Pilbara, Western Australia, consist of interlayered banded iron formation (BIF) and shale host rock formations within which a large number of open pit iron ore mines have been established. The slope stability of most of the mining excavations developed within these formations is controlled by the relatively low shear strength of the shale groups and shale bands, which are the weakest rock types. Shale formations range from fresh to highly weathered and are generally highly fissile when fresh, and clayey when weathered. An accurate understanding of the shear strength of these materials across the entire weathering continuum is therefore a key importance for assessing the slope stability of these mines.Historically defect laboratory testing results for the Pilbara mines have been analysed mechanically using direct shear testing (DST) to measure a number of geotechnical characteristics of the rock bedding and defects. This paper sets out the current practice in the industry in terms of the laboratory testing and presents a possible application of hyperspectral data to empirically correlate the shear strength of shale bedding with the relative mineralogy abundance on the bedding surface. This was achieved by creating both hyperspectral and geotechnical data sets for the same samples.In the study the shale samples were separated into three distinct assemblages: iron oxide + kaolinite, iron oxide + white mica + kaolinite, white mica + kaolinite, which had 40, nine and two samples respectively. Analysing these assemblages alongside DST data showed that samples with white mica had reduced non-variable shear strength, whereas samples with iron oxide + kaolinite had an overall higher shear strength but with a greater variance. It is inferred that the reduced shear strength in the white mica samples is due to the sheet (or plate) like structure of the mineral, giving it a weak stress plane. Confidence in the trends observed can be reinforced by expanding the data set in future works. The investigation also includes a discussion on weathering grade and addresses the question as to whether mineralogy abundances influence these characteristics in Hamersley shales.CITATION:Maldonado, A, Mercer, K G and Robert, A, 2017. The relationship between mineralogy and shear strength of Pilbara Hamersley Group shales across the weathering spectrum, in Proceedings Iron Ore 2017, pp 423–430 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By C. Richard Groves

As the level of technology applied in the electrical measurement, control, and display portions of mine hoist systems continues to advance, the issues and concerns associated with the ramifications of the application of microprocessor technology on the safety-related aspects of these systems become paramount. This report, in part tutorial, addresses several aspects of these concerns. Beginning with discussions of microprocessor-based system architectures, the report addresses some existing and anticipated uses of this technology in mine hoist systems and discusses safety related considerations associated with the areas of data derivation; control and display panels; and system reliability issues. The report concludes with electrical maintenance and inspection considerations associated with the safety assurance of microprocessor based mine hoist systems.

Jan 1, 1986

By Alicia Esther Ares

The family of Zn-Al (ZA), Zn-Ag and Zn-Al-Ag (ZINAG) alloys offers high mechanical properties, ease of finishing, the advantage of low energy and pollution-free melting. Also, present alternatives to the well developed alloy systems, such as brasses, bronzes, cast irons and aluminum alloys. The main objective of this paper is to measure thermal parameters in ZA, Zn-Ag and ZINAG hypoeutectic and hypereutectic alloys directionally solidified which present columnar, equiaxed and columnar to equiaxed transition structures (CET). Also, estimate the mechanical properties, such as microhardness and tensile parameters and correlate these with the thermal (cooling rate) and structural parameters (grain size and dendritic spacing). The different types of structures were analyzed with optical and scanning electron microscopy. The results showed the influence of concentration, microstructural arrangement and thermal conditions during solidification on the mechanical properties. The results of the present investigation are compared with previous experiments.

Jan 1, 2010

The La Colosa, Colombia porphyry gold deposit is currently in the pre-feasibility stage. This large deposit has many types of gold mineralization: native gold, electrum, and tellurides. These variations in the gold mineralization lead to variability in the gold recovery. The final process flowsheet may include gravity concentration with cyanide leaching. Metallurgical testwork is utilized to identify the zones of ore that may be problematic to recover. To help select the samples that represent the fluctuating variability zones, geometallurgical models are constructed using mineralogy and geology data. These zones are then wireframed and compared to the geological and structural models for spatial correlation. Samples for the variability testwork will be selected from these different zones to identify and analyse the effect the different gold mineralization types have on the recovery. By using geometallurgy to aid in the sample selection for metallurgical testwork, the variability in the ore body can be understood and constrained to aid in process optimization.

Feb 27, 2013

By Gerald T. Homce, James C. Cawley

Electrical arcing injuries are the most common form of electrical injury in mining. MSHA data show that 381 "non-contact electric arc burn" injuries occurred in the mining industry from 1996 - 2005. A more detailed study of data from 1990-2001 showed that five types of apparatus - circuit breakers, conductors, nonpowered hand tools, electrical meters and test leads, and connectors and plugs were involved in two-thirds of the lost workday injuries. Many of the protections from electrical arcing injury available to workers in other industries stem from the application of National Fire Protection Association Standard 70E - Standard for Electrical Safety in the Workplace (NFPA 70E). NFPA 70E is a generally accepted industry guideline document, but excludes underground mining from its scope. Many of its practices and procedures, however, can be applied in the mining workplace to supplement the existing electrical safety requirements of Title 30 Code of Federal Regulations. This paper describes how NFPA 70E can be applied to mining workplaces after an analysis of the mine power system electrical arcing hazards has been completed (and Hazard/Risk Categories determined) using the tables from NFPA 70E or the calculation method as described in IEEE 1584. NFPA 70E can then be used to determine the levels and types of personal protective equipment (PPE) needed to protect miners against burn injuries. Appropriate lockout and tagout (LOTO) procedures for use in the mining industry are also described. Suggestions for better selection of electrically-rated hand tools are included. Recommendations for electrical meter selection and use based on transient withstand capability are also discussed.

By Seal. Thom

Large heap leach operations around the world contain significant under-leached metal values that present recovery challenges to operators. The first challenge is to find the location of the highest inventory. High resolution resistivity ? has proven sensitive enough to detect such zones in the interior of heap leach pads to target treatment or re-leaching. Newmont Mining Corp. has adapted the high pressure fracturing technology, used in oil wells to stimulate select zones in heap leach pads to add reagents in 3-D for re-leaching, changing zonal chemistry for improved recovery and heap closure. High Resolution Resistivity ? is able to subsequently monitor injected solution flow and determine directional permeability during Hydro-Jex stimulation. The combination of these technologies has shown strong economic success, for selecting targets in the heaps and monitoring solution application. These technologies are now available to the mining industry for adoption.

Jan 1, 2008

By R. R. Sayers

"The number of investigations reported during the past year indicates that control of the health hazard due to abnormal air conditions is still a matter of serious consideration in the mining, metallurgical, and allied industries.Australia. - In an investigation into the health and working conditions of employees in the mining industry of Tasmania and Victoria3, it was found that although pulmonary tuberculosis may occur early in life, silicosis is e disease of slow evolution and does not appear frequently under the ace of 40. A period of at least ten years in the industry was found necessary to produce silicosis, and in no case was the disease found in those who had not worked underground. A very high incidence of silicosis was found in all fields among those who had worked underground 20 years and longer. There was some evidence that silicosis complicated by tuberculosis may occur earlier than uncomplicated silicosis.England. - In a paper presented before the Section on Occupational Diseases of the British Medical Association, Dr. E. L. Middleton, the medical inspector of factories, called attention4 to the occurrence of silicosis in various industries throughout the country.punitive on some quite harmless industries. Thus Middleton says: ""Where the amount of dust is small the action of the phagocytes is likely to be effective, but where it is great . . ."" What dosage is indicated by ""small"" and ""great"" in this connexion? If the meaning of ""small"" were known, would it be correct to go on to say, as he does, ""each successive dose of silica produces a summation of effects""? Then, again, would it be fair to say ""a comparatively brief period of exposure may be the only determining factor""? What, in minutes, hours, or days per week, per month,' or year, is intended by ""a comparatively brief period""? ""Intermittency of the process"" is another expression used in summing up the reasons for and against a standardization of air purity by a gravimetric process or enumeration of the particles; the arguments against such a standardization are, by Middleton, considered strong, but they are by no means convincing to us. A standard has been accepted in respect of the amount of lead in milligrams per 10 cubic metres of air; Dr. Ronald Lane showed in another paper read that adherence to this makes the occurrence of poisoning highly improbable. Mavrogordato has placed on record figures of silica dust at different stages of the improvements in the workings of the Rand mines, and such a control is in constant operation in them today.We emphasize these points because apparently the Government has taken the unusual course of legislating first and postponing inquiry to a later date, as in the ""Various Industries (Silicosis) Scheme, 1939."" The insurance companies also have a considerable interest in the matter of compensation for the silicosis risk. Where exposure - as in the refractories industries, the grinding industries, sandstone industry, and pottery industry - is day in and day out, they rightly demand a premium far higher than for any other disease scheduled under the Workmen's Compensation Act - 5 per cent on the wages bill. row every industrial employer, such as the paint and varnish manufacturer, who has a sack of crushed silica in his store .room, from which he extracts once a week enough to make a paste With spirit and add to his other ingredients in order to give them the necessary ""bite,"" becomes involved, and may have to abandon the use of the material or pay 8 per cent on his wages bill for an absolutely negligible risk.. For meting out justice standardization seems urgently called for."

Feb 1, 1930

By Richard Peaker, Jens Lichter, Alexander V. Potapov

"The recent combination of Computational Fluid Dynamics (CFD) and Discrete Element Modeling (DEM) can provide considerable insight into the performance of flotation cells. One area of interest from a fundamental equipment design perspective has been the influence of flotation cell size and the inflow rate on the metallurgical performance of the cell. One of the specific design objectives when increasing the size of flotation cells, or increasing the feed flow to the flotation cell, is to ensure that the feed stream flowing into the cell does not have an opportunity to bypass the mechanism.This paper describes the initial modeling efforts to quantify the inter-relationship of cell size, inflow rates, and feed and discharge box placement, on the retention time distribution of solids in the flotation cell, and the fraction of particles that bypass the mechanism on a size by size basis.INTRODUCTIONThe great majority of newly installed cells in mineral processing plants world-wide are of the cylindrical tank design and this tank shape offers a number of hydraulic advantages over the older style of square cells. Cylindrical cells give symmetrical flow patterns and by careful design of the mechanism and tank internals, the flow patterns generated can concentrate the more intense mixing in the lower portion of the cell to promote good solids suspension and particlebubble contact. Simultaneously, cylindrical tank design gives a more quiescent upper zone for particle-bubble transport into the froth zone. These symmetrical flow patterns are naturally disturbed in normal operation by the slurry inflow and outflow from the individual cells. The challenge for flotation cell designers is to determine the magnitude of these flow disturbances, and to assess whether or when the inflow and outflow rates have a sufficient impact on the hydraulic flow patterns so as to potentially affect the metallurgical performance of the flotation cell."

Jan 1, 2007

By Douglas W. Fuerstenau

This report presents the results of an investigation of comminution in tumbling mills. Five different topics involved with ball mill and rod mill grinding kinetics were studied and the results analyzed in terms of phenomenological size reduction and transport models. Continuous rod mill grinding was found to be characterized by high Peclet numbers which permit simulation to be carried out by several methods. The dry batch ball mill grinding of mineral mixtures showed that the breakage rates of the components were composition-dependent but time-independent and were normalizable with specific energy. Locked-cycle tests on mineral mixtures showed that a grinding circuit may take a long time to attain steady-state, during which time the composition of the mill holdings, and hence the breakage rates of the components, continuously changed. This study revealed that under plant conditions, grinding circuits can be in transience perpetually. The transport of mineral mixtures through drums was found to exhibit complex size and/or density-dependent segregation. However, the grinding media in a ball mill can eliminate such segregation, thereby simplifying the modeling of the continuous grinding of complex feeds. Wet batch rod mill grinding on single minerals divulged that the normalizability of breakage kinetics is valid for slurries of constant pulp density at different hold-ups but cannot be extended to slurries varying in pulp density.

Jan 1, 1983

By Gunderson C. T

The use of carbide tipped integral drill steels and detachable bits is discussed in relation to the means of drilling or cutting employed. It is stressed that only by correct use can the full value of these tools be realised.Factors affecting carbide quality, the design of shanking steels and the requirements and techniques of brazing in inserts are considered.It is essential that the brazed jointing between carbide and steel be strong but ductile. The methods used for the manufacture of carbide tipped tools are briefly outlined.INTRODUCTIONIn recent years the application of tungsten carbide to various mining tools in the mining industry, has developed to the stage where it is now regarded as an essential item in the production of coal and metal ores. In fact it is claimed that certain mining operations would not be possible if it were not for the benefits obtainable from the characteristic properties of tungsten carbide. The advantages of this hardmetal have, to some extent, influenced manufacturers to revise design specifiations of some machines, while againsome machines have actually been designed with tungsten carbide as their basic medium for operation.In general the applications fall into the following three categories:(a) Drilling hard rock by percussive means.(b) Drilling soft rock and coal by rotary means.(c) Coal cuttingThis paper is concerned with tungsten carbide tools associated with these three activities in Australia, the effectiveness of their application and significant points in their design and manufacture.

Jan 1, 1958

By Glenn D. Lyle

As part of an initiative to improve value in mining, CEMI is developing a handbook on best practice in mine design. Various formats were examined, and of these, the wiki was selected as being most suitable. Being web-based, its global reach and capability of being continuously updated allows the wiki to evolve as new knowledge is generated, and to capture the diversity of experience of practitioners in the mining industry. While wikis have many advantages in terms of organizing content and searching, their ability to be edited by users is often seen as a negative characteristic for quality control. To ensure reliability of information content, author attribution, specific authorship models, and a peer review process have been implemented, in addition to the standard version tracking capability of wikis. The first phase of the project concentrates on topics related to underground hard rock mine design. The scope will be expanded to cover other aspects of mining as the project matures. Strategic partnerships with various organizations, such as the CIM, and CANMET, are being formed to provide a wide range of seed material to stimulate growth of the site. www.minedesignwiki.org

May 1, 2011

By P. J. N. Pells

A good thing is becoming a bad thing. Rock mass classification systems, that are so excellent for communications between engineers and geologists, and that can be valuable in categorizing project experience, are emasculating engineering geology and rock mechanics. Some engineering geologists have been sucked into thinking that Q and RMR values are all that is needed for engineering purposes, and seem to have put aside what can be learned from structural geology and geomorphology. Many rock mechanics engineers seem to have forgotten the scientific method. This paper attempts to redress the situation by showing how mechanics can be used in rock engineering to design with a similar rigour to that used in the fields of structural engineering, hydraulics and soil mechanics. It also attempts to remind practitioners of what can be achieved by skilled engineering geology.

Jan 1, 2008

By Andrew G. Patton

The Alimak mining method was introduced at the David Bell mine in 1998 to extract an otherwise uneconomic and inaccessible reserve. The success associated with the extraction of these reserves led to major expansion of the method. To date, results have been extremely positive in terms of grade control, reduced dilution, stope recoveries, productivities and mining costs. It is hoped that through further development of the method at David Bell mine we will continue to see positive results in these areas and be able to increase mineable reserves to include proven resources that do not currently meet the criteria of our current stoping plan.

Oct 1, 2001

By J. Cseff

A variety of shaft and hoist equipment exists in the United States. Nearly all hoist systems are electrically driven. Machine elements which comprise the hoists and ancilliary equipment include bearings, shafting, drums, gear reducers, couplings, brakes, clutches, sheaves and electrical motors. Volume I, Systems Description, describes the various components encountered in most mine hoist and shaft installations, and brief descriptions of functions and constructions. Hoist ropes and balance ropes are specifically excluded from this report. Associated with the hoisting system is the headgear, shaft and equipment, loading/dumping facilities and the actual conveyances and their rope attachments. Volume II, Inspection and Maintenance Procedures, discusses scheduled Inspection and preventative maintenance in general terms. Preventive scheduled inspection and maintenance procedures assist in the smooth operation of mine hoisting plant, by the prevention of unscheduled or catastrophic equipment failure and its attendant downtime. Schedules and overall maintenance planning is required at the management level. Records and equipment logs must record inspection and maintenance, and unusual operations or incidents. A cross reference between MSHA regulations and various equipment components is included as part of the report. A discussion of the various non-destructive testing methods which may be applied to hoisting equipment is also included.

Jan 1, 1981

Preparation of MgO Nano-Particles with Magnesite

Sep 13, 2010

The design of excavations in high displacement mining environments requires consideration of both the load and displacement capacity of the ground reinforcement and support systems. This paper is a case study on the design of point anchored rebar bolts using laboratory tests and field trials at the Ridgeway Deeps block cave. A laboratory testing program was carried out to measure the mechanical properties of the Strata Control Systems R27 Secura resin bolt which is currently being installed on the extraction and undercut level at the Ridgeway Deeps block cave. The aim was to quantify elastic, plastic and energy parameters for various bolt, mesh and plate systems. Experiments were performed on bar segments, bolt/plate systems, and bolt/plate/mesh/resin systems. The mechanical properties were calculated from tensile tests with a 500 kN Avery machine. Load-displacement data was collected from four different testing configurations. The laboratory results are compared with underground measurements and observations of bolt performance.

Nov 25, 2010

By Theodore S. Jordan

The discovery of a major porphyry-type copper deposit on the Papago Indian Reservation in Pinal County, Arizona was announced by El Paso Natural Gas Company in 1968. The deposit, known as the Lakeshore Property, contained an estimated 470 million tons of sulfides and oxides averaging 0.75 percent copper. History and Geology of the area have been described by Harper and Reynolds (1969). El Paso subsequently&apos; entered into the agreement for joint development of the property with Hecla Mining Company, with Hecla as the operator. The ore body consisted of three types of mineralization: 1) Disseminated Oxide Ore, <1% Cu 2) Disseminated Sulfide Ore, <1% Cu 3) Tactite Ore, >1% Cu

Jan 1, 1985