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By P. S. Haury, Thomas C. Denton

"INTRODUCTION AND RESUMEThe Reward zinc property was one of the first selected for exploration by the Bureau of Mines at time when zinc supplies for war production were very short. Preliminary examination indicated that an appreciable tonnage of zinc that could be developed for early production might be found by diamond drilling. The geology was mapped by the Federal Geological Survey, and 14 holes were diamond drilled by the Bureau of Mines. This work was started in September 1942 and completed in September 1943.The Reward is an old property in southwestern Pinal County, 26 miles from Casa Grande on the Southern Pacific Railroad. Mining was begun in the early 1880's and was continued intermittently by several operators to about 1917. About 400,0oo pounds of copper was produced from the north¬eastern part of the property, mainly from a 600-foot incline in oxidized copper ore that replaced a bed of limestone. This ore was mined out. A 400-foot vertical shaft in the copper area was inaccessible. A 325-foot vertical shaft had been sunk near the southwest end of the zinc-bearing area, and a 600-foot crosscut tunnel had been driven near the northeast end of the zinc area, but little zinc ore was produced. There were several shallow inclines and numerous surface pits between the main workings.The ores were deposited in Paleozaic limestones that strike northeast and dip about 40 degrees northwest. These are capped by Cretaceous clastic and volcanic rocks in the zinc area. The outcrops show mineralization in a segment of the limestone 4,500 feet long, which is limited by large cross faults at each end. Another large fault, which strikes north, separates the northeast third of the mineralized belt from the remainder. Copper predominates northeast of this fault and zinc southwest of it. The ore beds are cut by numerous small cross faults. Ore was deposited for short distances along some of these, but more of it made out from the fissures along certain replaceable limestone beds."

Nov 1, 1946

By R. E. Gilmore

Introduction The Sydney coal-field extends for a distance of thirty miles along the northeastern coast of Cape Breton island. At a central focal point at the tip of the south arm of Sydney harbour, seven miles or so in from the Atlantic ocean, is the city of Sydney, with Port Morien to the southeast and Sydney Mines to the north . Mining centres along the ocean coast between these points include Birchgrove, Reserve, Glace Bay, and Waterford. The field is divided into three districts or 'basins', namely, Morien basin to the south, Glace Bay in the centre, and the Lingan-Sydney Mines basin to the northeast. The eastern and western portions of the latter are known as the Lingan and the Sydney Mines basins, respectively. Six distinct coal seams are described as existing in the Morien basin, nine in the Glace Bay basin, and six in both the Lingan and the Sydney Mines basin. Although known by different names in the several basins, a definite continuity of the seams has been established.

Jan 1, 1933

By Jie Zhou

Mining mobile equipment is becoming larger in order to lower operation cost and increase productivity; however, their performance characteristics are often limited by the tire capabilities. Although considerable progress has been made in the field of tire research, the lack of comprehensive knowledge on tire performance characteristics impedes the advancement of off-the-road tires. Longer haul roads, and a severe operating environment make tires more vulnerable than other components of a vehicle. Furthermore, due to a limited availability of large tires, mines are facing shortages. Thus mines and tire service companies are keen to improve tire performance, extend tire life and hence lower operating costs. This paper reviews the relevant tire performance research, analyzes tire interactions with the surrounding environment, tire maintenance practices and operational issues using a case study based on data collected during an ongoing project with Fountain Tire.

May 1, 2006

By K. Heindlhofer

Estimates of the "plasticity" of a metal are commonly deduced from three types of test—tensile, torsion and impact. The several results have been more or less at variance, though this disparity has attracted little notice, largely perhaps because they have been expressed in different terms. The discrepancy between the results of the three tests becomes obvious when each is made at a series of low temperatures, for the temperature range within which the "plasticity" of iron largely disappears proves to be very different in the three types of test. The rather abrupt disappearance of "plasticity" of iron within a narrow temperature range cannot be due to any physicochemical change (such as a precipitation) taking place in the material at that time, because the original plasticity is immediately regained when the temperature of the material is brought above the sensitive range. Accordingly this difference in behavior shows that the "plasticity" of a metal depends upon the mode of action of the stresses which produce the deformation, and therefore upon the method of test. Analysis of the stresses leads to the conclusion that the observed plasticity of a metal is determined by the relation between its resistance to rupture by separation and its resistance to shear (slip), on the one hand, and between the effective normal and shearing stresses on the other; and that the relation between the two resistances does not in general remain constant with change of temperature, and may somehow be altered to some extent by the previous treatment of the specimen. This suggests the view that the results of none of the usual mechanical tests are directly comparable even for a single metal tested at a series of temperatures, or for a series of metals at one temperature, because the proportion of the total resistance of the metal to the test contributed by the

Jan 1, 1935

By K. Heindlhofer

Estimates of the "plasticity" of a metal are commonly deduced from three types of test—tensile, torsion and impact. The several results have been more or less at variance, though this disparity has attracted little notice, largely perhaps because they have been expressed in different terms. The discrepancy between the results of the three tests becomes obvious when each is made at a series of low temperatures, for the temperature range within which the "plasticity" of iron largely disappears proves to be very different in the three types of test. The rather abrupt disappearance of "plasticity" of iron within a narrow temperature range cannot be due to any physicochemical change (such as a precipitation) taking place in the material at that time, because the original plasticity is immediately regained when the temperature of the material is brought above the sensitive range. Accordingly this difference in behavior shows that the "plasticity" of a metal depends upon the mode of action of the stresses which produce the deformation, and therefore upon the method of test. Analysis of the stresses leads to the conclusion that the observed plasticity of a metal is determined by the relation between its resistance to rupture by separation and its resistance to shear (slip), on the one hand, and between the effective normal and shearing stresses on the other; and that the relation between the two resistances does not in general remain constant with change of temperature, and may somehow be altered to some extent by the previous treatment of the specimen. This suggests the view that the results of none of the usual mechanical tests are directly comparable even for a single metal tested at a series of temperatures, or for a series of metals at one temperature, because the proportion of the total resistance of the metal to the test contributed by the

Jan 1, 1935

By Ruilin Yang

The following simple equations are frequently used within the blast vibration community;PPA f PPV v = 2p · , PPV f PPD d = 2p · ,a f PPV PPA 2p = , and v f PPD PPV 2p = where, PPA is the peak particle acceleration, PPV is the peak particle velocity, PPD is the peak particle displacement, and fa , fv , and fd are the frequency of the particle acceleration, particle velocity, and particle displacement vibration waveforms, respectively. Conceptually, the frequency should be selected to be the frequency of a simple sinusoidal wave that is used to approximate the blast vibration. In the literature, f is sometimes chosen as the dominant frequency (fdm) estimated from the Fast Fourier Transform (FFT) of the blast vibration wave, on other occasions, f is chosen to be the principal frequency (fpr) from the vibration cycle with the peak vibration amplitude.

Jan 1, 2012

By H. N. Egan

Faced with a severe disposal problem of their fines from a coal mine in the heart of the Appalachian Mountains of extreme eastern Kentucky, Eastern Coal Corporation has built a special plant to pelletize the fines into high quality coal pellets meeting the requirements of the metallurgical market. These low-ash, low-sulfur pellets measuring 3/4 x 3/8 in. contain less than 1.5% moisture and have the same stability as raw coal of the same size. Although Eastern Coal is mining 6000 tpd, the company had, until recently, no provision to recover the fine coal which was included with the plant effluent pumped to a 12-acre refuse pond. The pond, impounded behind the coarse refuse dump, rose 15 ft last year and obviously no pond can stand many years at this rate. Limited pond space in this rugged area of steep hills and narrow valleys dictated a revised disposal method.

Jan 11, 1967

By H. Haselhuhn

Filtration of hematite ore slurries can be a bottleneck in some hematite processing plants due to inadequate filtration rates caused by the dispersion of fine particles. Flocculation of fine particles in the slurry decreases the specific cake resistance of the filter cake allowing for increased filtration rates. CO2 sparging of hematite slurry was shown to increase the filtration rate by altering the pH and the surface chemistry of the particles. It was shown that an increase in filtration rate of 278% can be accomplished by lowering the pH from 11 to 6.5 using CO2. This was attributed to increased flocculation of hematite and silica particles in the ore.

Jan 1, 2012

By E. A. Metz

Perfect combustion in an engine would produce only water vapor, carbon dioxide and nitrogen as by-products; however, complete combustion is never achieved. As a mobile power plant, the diesel engine is relatively inefficient in terms of energy produced from the energy potential of the fuel. The diesel is not a perfect engine. The fuel burned can undergo a very large number of reactions in the combustion chamber. It only stands to reason that a large number of compounds are contained in the exhaust, actually, thousands of chemicals. The exhaust can be broadly divided into a gaseous phase and a particulate phase. Each phase is made up of organic and inorganic compounds. The vapor phase contains carbon monoxide, sulfur dioxide, various oxides of nitrogen and many hydrocarbons. The particulate phase contains clusters of respirable inorganic particles made mostly of carbon. This paper will address the health hazards, as we know them today, of the major components of the particulate phase in the exhaust of diesel engines. It will briefly examine the operational factors of the diesel engine as it applies to particulate emissions. Longitudinal studies of occupationally exposed miners are needed with documentation of levels of exposure before a chronic effect of exposure can be determined. At this time, it is not possible to conclude from human studies the level of diesel exhaust exposure that results in the observed lung cancer risk.

Jan 1, 2001

By Bill Starke

The acceptance of AugerCast piles in Canada has been limited. Many engineers are apprehensive about the quality of the piles produced by this method. However, advances in the sensing instruments and computer technology can now provide satisfactory levels of quality assurance. Post construction tests such as the sonic echo method can give an indication of pile shaft integrity. Computerized monitoring of the pile installation process is an immediate and more positive method of quality assurance. The computer continuously measures and records the parameters which indicate the quality of the pile. If these parameters do not indicate a satisfactory pile, it is replaced before the concrete hardens. Computerized monitoring of the installation process is another tool available to the engineer. The data from this system analyzed with soil borings, site inspections, and possibly sonic tests can provide the engineer with enough information for pile certification.

Jan 1, 1997

Paper written on project work carried out in partial fulfilment of BSc Engineering (Mining) The aim of this project is to determine whether certain pillars occurring within the no. 1 shaft and no. 2 sub-shaft ground are feasible for extraction. The extraction of these pillars is essential in prolonging the life of Kloof Main Shaft as its VCR resource becomes depleted. Extraction of these pillars will require a combination of designs and factors, with rock mechanics and ventilation being the main considerations. Primarily for the pillar extraction, an initial production target of150 kg gold, mine able in one year from commencement of ?opening up? was set. The planned target has been exceeded and the feasible pillars identified are expected to yield an additional 1 390 kg of gold to the shaft?s production profile. However, not all the required ventilation designs have been completed to date, the reason being that at the time of the project, many of the pillar areas were inaccessible and thus ventilation conditions are unknown. This project is therefore an ongoing process and will require further design once all targeted pillar areas have been opened up. A preliminary costing analysis of the pillar mining was performed and it was found that all targeted pillars with the exception of 38?61 pillar are profitable.

Jan 1, 2005

By Tex M. Kubacki

In 2007, the University of Utah Seismograph Stations (UUSS) temporarily expanded its seismic monitoring network in Emery County, Utah, in response to the August 6 Crandall Canyon mine collapse that trapped six workers. In spite of this additional coverage, no seismic events were located in the area during a six-day period (gap) from August 8 to August 13. The Mine Safety and Health Administration (MSHA) ?Command Center Log Books? however, contain references to 16 instances of underground ?bumping? and ?bouncing? that occurred during the gap. When ground truth information provided by the log books is compared to the raw seismic data recorded by the UUSS network, the correlation offers insight into the chronology of mininginduced seismicity (MIS) in the aftermath of the collapse. The new research focuses on identifying and locating seismic events that occurred during the six-day gap using double-difference relocation techniques and correlating them with log book ground truth. Ten seismic events were identified in the vicinity of the mine during the six-day gap, ranging in magnitude from coda magnitude (MC) 0.5 to 1.4. Three of these events were amenable to location by double-difference techniques. The location of one of these events is directly confirmed by ground truth information from the log books. As a result of this new research, the accuracy of Crandall Canyon double-difference locations has been improved, and the number of events correlated with ground truth information has increased. The seismic events occurring in and around the collapsed area appear in two distinct sections of the mine?east and west of the center of collapse. It was originally reported that the post-collapse events occurred in episodic clusters. The first two episodes occurred to the east, followed in time by a cluster on the west, and then by a third episode on the east. With the addition of new events to the data set, this pattern is no longer as clear, although the events still occur in clusters. Only one MIS cluster was found to occur within the bounds of the minimum estimated collapse area (Pechmann et al., 2008).

Jan 1, 2012

By S. M. Shelton, A. L. Engel

"This report presents the results of investigations of ore-testing projects assigned to the Ore-Dressing Section, Metallurgical Division, Bureau of Mines, at the Mississippi Valley Experiment Station, Rolla Mo. During the fiscal year ended June 30, 1941.The manner of approving ore-testing projects has been explained in a previous reports. 4/ The testing procedures likewise have been described. 5/The treatment methods described are based upon laboratory experiments with small amounts of sample and naturally are subject to the inherent, normal, limiting conditions of such procedure. It is not intended to describe treatments in detail, but rather to indicate applicable methods. Local operating conditions, when the laboratory results are applied to plant operations, may require further study. Large-scale pilot-plant tests should be made before commercial operations are begun, so that translation from the experimental stage will yield satisfactory results."

Mar 1, 1942

Automation in underground mining enhances safety and leads to economic efficiency. In the past many efforts have been made on the automation of longwall shearer operation. With respect to the ultimate goal of automation, ie self controlled operation, coal bed boundary detection is one of the key problems. For longwall human labor is necessary in order to detect the exact position of the coal seam to be excavated. The authors present a sensor concept based on infrared technology and pattern recognition which will solve this problem. The very harsh underground conditions set high demands on the implemented sensors. The combination of infrared sensors and powerful processing algorithms is part of the innovative concept for automation of the new Eickhoff Bergbautechnik GmbH SL 750 shearer loader. The multi-sensor automation system EiControlPlus which is designed for the complete detection of the machine environment fills in the gap in the coal-excavation automation by building a recognition system that turns the shearer loader into an 'intelligent machine' which is capable of detecting the correct position of the seam to be excavated and thus enables human-free coal mining.

Dec 6, 2010

By Heather N. Dougherty

In the absence of values for each influencing parameter and a known relationship of input-output space, novel approaches should be implemented as proxy solutions to mathematically complicated problems. Proxy solutions can be in the form of linear or non-linear multiple regression equations. Predicting the performance of gob gas ventholes is one of these mathematically complicated problems as it is difficult to know the exact relationships between various parameters influencing gob gas venthole (GGV) performance from active and sealed (completed) longwall panels. In this paper, a discussion of the NIOSH-developed software suite for methane control and prediction (MCP) based on an artificial neural network (ANN) is presented. The application of the ANN-based software suite to develop algebraic relationships for gob gas venthole performance prediction in sealed and active longwall panels is sought. Output information obtained from the NIOSH-MCP software as a response to various input parameters were used to create an input-output database for total flow and methane percentage from GGVs operating in active mines during completed and sealed panel situations. Due to the multi-variable nature of the software, outputs generated using the software for various inputs were used to develop analytical equations first using linear and then second using non-linear multivariable regression techniques. The advantage of this method is its ability to better understand the significant parameters of the relationships between the inputs and outputs for gob gas venthole production in active and sealed panels and to be able to predict their performances using relatively simple analytical functions.

Jan 1, 2010

By M. Prats

Most of the information available on the heat efficiency of hot fluid injection processes, both water and steam, has been obtained from calculated temperature distributions in the pay zone and adjacent formations. The usual approach has been to write the heat balance equations in terms of the temperatures, and then to introduce whatever simplifications are necessary to help obtain an analytical or a numerical solution. In either case, the assumption has often been made that the vertical thermal conductivity in the flooded interval is infinite, so that the temperatures within the flooded interval are then independent of vertical position. Because it was first made by Lauwerier,l and has been used extensively since, this assumption will be referred to as the Lauwerier assumption. Excellent reviews of the literature on the heat efficiency of hot fluid injection processes have been given by Spillette,2 Flock et al.,3 and Ramney.4 Of course, the most significant contributions take into account the effect of a finite vertical thermal conductivity on the vertical temperature profile. The most general analytic expression for the heat efficiency of a hot fluid injection process is that of Antimirov5 who considers injection of a heated incompressible fluid into a reservoir through an arbitrary number of wells. The rate of heat injection into the reservoir, as well as the injection temperature, is an arbitrary function of time. The geometry of the horizontal flow is arbitrary, although the reservoir is considered to be of uniform thickness and properties and to be of infinite areal extent. Heat transfer within the reservoir is by horizontal convection and conduc- tion, and by vertical conduction. In the formations adjacent to the flooded interval, heat transfer is by conduction in any direction. Thus, the available expression for the heat efficiency due to hot water injection has been developed for rather general conditions. This degree of applicability has not been obtained for other thermal recovery processes. By making the Lauwerier assumption we have been able to obtain expressions for the heat efficiency that are essentially independent of the thermal recovery process, be it steam, hot-water, or underground combustion. Clearly, then, the approach followed here is more restrictive than that of Antimirov5 in that it uses the Lauwerier assumption. At the same time less restrictive assumptions are made about the horizontal heat transfer mechanisms, either in the flooded interval or in the formations adjacent to it. The main difference between our approach and that of other investigators is that the heat balance in the pay zone is expressed for the pay zone as a whole rather than for a volume element within it. The Lauwerier assumption is introduced after the problem is developed along these lines as far as possible. The details of the development of the heat efficiency are given in the Appendix, while the main features of the model are discussed in the next section. Results and their implications are discussed later in a separate section. The Model Certain assumptions have been made to determine

Jan 1, 1970

By T. Plikas, L. H. Gunnewiek, L. Oshinowo

Electric furnace smelting is one of the principal unit operations for ferroalloy production, and increased process intensity, improved availability, minimal maintenance and a longer campaign life are common objectives for electric furnace operation in order to obtain favourable economics of production. Furnace designers have continued to develop innovative solutions that have allowed these objectives to be realised, e.g., furnace cooling systems, and numerical modelling plays a key role in the design process. Enhanced understanding of the energy transfer process in the furnace and the ability to develop, evaluate and optimise components of the crucible design to match process requirements are the key motivators for modelling. This paper provides an overview of recent applications of numerical modelling to the design of electric furnaces. The aim is to illustrate what can be done, and identify areas where further work is needed in this field. Examples include furnace bath modelling, crucible cooling system design, taphole design, baking of Soderberg electrodes, off-gas systems, and fume control and building ventilation. It is argued that the trend is for numerical models to become more encompassing while at the same time more accessible, and therefore further improvements in furnace design will be realised with continued and well validated modelling efforts.

Jan 1, 2004

This publication summarizes the in-house and contract research projects programmed for fiscal year 1984 by the Bureau of Mines under its Conservation and Development activity. The document provides a mechanism for interested parties to gain insight into projects of the Bureau's Conservation and Development research program. The objective of the Conservation and Development Program is to provide the technological advances needed to stimulate the mining of domestic deposits containing critical, strategic, and other essential minerals in compliance with existing regulations and at costs sufficiently low to be competitive in world markets. Research efforts are directed toward improving the fundamental understanding of processes and procedures involved in the production of minerals. The overall goals will be accomplished by investigating alternative mining methods to increase domestic production of critical and strategic minerals from low-grade deposits; expanding the technology for the economic and efficient extraction of minerals consistent with cost-effective compliance with environmental regulations; and advancing the technologies needed to insure an adequate supply of coal.

Jan 1, 1984

By B. M. Monaghan

"The developments of the 1950s and 1960s have seen Canada become an international source of iron ore, trading in all geographical areas and hemispheres. Canada's production will significantly increase in the next decade. However, although the outlook is bright, iron ore producers cannot be complacent. Instead, we must weigh the factors that have brought about the development of the Canadian iron ore industry and examine the probable changes for the next decade that will affect its growth.Looking ahead in the 1970s, competition will be severe. Pressure on prices will continue as new sources of supply bid for long-term contracts and as steel producers continue to develop mines around the world. Rising costs will make these pressures more severe. We must balance the growth of the world's steel makers with the emergence of new supplies of iron ore. The iron ore industry is now part of a new era in which demand and supply are intermeshed, and the developments around the world are acting on the Canadian iron ore industry's future."

Jan 1, 1971

By Harry Asche

The last 12 months has seen the construction of the first Earth Pressure Balance (EPB) TBM excavated tunnel in New Zealand on the Project Hobson sewer storage tunnel for Watercare Services Limited, with the concurrent excavation of the second EPB tunnel on the Rosedale Outfall project for North Shore City Council. Together these tunnels involve a total length of 6km and follow an 8 year pause in TBM activity in Auckland. TBM performance on these two projects is thus of significant interest as there are four major tunneling projects totaling over NZ$8B being planned for Auckland, in similar ground conditions. Auckland?s bedrock is a weak sandstone/siltstone (East Coast Bays Formation), subject to infilled paleovalleys. The geology in the region has been significantly influenced by volcanic activity; 49 volcanoes are present within 20km of the city centre. The paper describes the design and construction challenges for the projects, including TBM performance, ?sticky spoil? management, and risks associated with basalt lava flows and two paleovalleys. Watercare?s Project Hobson also saw the successful implementation of a Geotechnical Baseline Report?one of the first uses of this type of document in Australasia. Rosedale Outfall is designed for high internal water pressures with varying hydraulic flows, with the risk of exfiltration explicitly addressed.