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By Lucien Eaton

THE use of filling in mines is less common in the United States than it is in Europe, where in some places it is required by law. In most cases the filling is placed by hand, and the material used for this purpose is the waste from development and that sorted from the ore in the stopes. When these sources provide an insufficient supply, additional rock must be quarried on surface or mined underground, or some other material :st be used. In different parts of the world sand, clay, gravel, culm, nulated slag, mill tailings, and even ashes, have been used as filling material in place of or in conjunction with rock. Of all the materials used for filling the best is probably clean sand. Gravel, finely crushed rock, granulated slag and coarse mill tailings are almost as good, and the methods used for placing and confining sand will apply equally well to any of these. The advantages of sand are its comparatively slight compressibility and the ease, economy and convenience with which it may be placed. On account of the voids, which necessarily occur in fills made of coarse waste, such fills will compress 10 to 25 per cent before they develop their full strength, whereas clean sand seldom compresses more than 5 per cent. Sand is especially desirable when practically complete filling is required, and sand derived from mill tailings, especially when not thoroughly cleaned, has been remarkably effective in sealing off and extinguishing mine fires. When natural sand is available on surface, or when it can be obtained from the mill tailings or tailings dump, the cost of using this material for fill will probably be considerably less than that of rock. In this paper it is not proposed to discuss all methods of filling, butt to describe some of the methods used for placing sand fill and to make a brief comparison of their merits.

Jan 1, 1932

The Bureau of Mines conducted large-scale laboratory copper ore leaching tests to enable improving copper recovery from large dump-leaching operations. This was done by comparing leaching progress when copper was recovered from recycled leach liquor either by cementation or by solvent extraction. Copper was leached from 7-ton ore samples at room temperature using pH 2 ferric sulfate solutions. With are samples containing 11 percent minus 0.5-inch fines, no marked advantage in using either of the copper recovery methods was evident after 416 days of leaching. With ore containing 32 percent minus 0.5-inch fines, solvent extraction of copper was advantageous in that 60 percent of the copper was extracted after 568 days, whereas only 48 percent of the copper was extracted when cementation was used. Less acid was consumed during leaching when solvent extraction, rather than cementation, was used for copper recovery. Iron, contributed by cementation with scrap iron, plugged the ore bed containing 32 percent fines.

Jan 1, 1981

By X. S. Tan

This paper deals with the analysis of stress condition on the interface between two types of floor rock materials when the vertical stress is larger, or when the horizontal stress is larger in a rectangular opening. It indicates that the floor Failure and the failure stress of floor rocks are closely related. It also demonstrates that a larger horizontal stress is one of the most important factors in increasing the potential for floor rock failure and floor heave.

Jan 1, 1990

Wire rope, when used for hoisting on a mine is one of the most vulnerable units in the most expensive group of installations on the mine. With the introduction of hoisting on the Koepe sheave, a new technique was established. This innovation brought with it certain advantages which long had been recognized and which are being developed further.A need exists for the development of an infallible non-destructive testing device for wire ropes and it is axiomatic that the development and application of such a device should be coupled with the physical examination of mine hoisting systems. Therefore an integrated type of research programme is necessary in order to correlate the effect of shock loading with rope damage, which may be detected ultimately bynon-destructive means. This paper reviews certain historical aspects of investigations on this topic and it outlines a policy for research which can cope with a.c. or d.c. methods of excitation of the rope.INTRODUCTIONThe importance of wire rope in mining operations is often not fully recognized. A wire rope when used for hoisting in a mine shaft should be regarded as a "machine" forming part of a system of machines, and consequently it should be specified as such when it is purchased, it should be maintained as such during its working life, and it should be discarded only when it has done its duty and has been rendered either unsafe or uneconomic for further use.Every mine shaft, vertical or inclined, has in it one or more wire ropes which are used to transport men, material, and ore. Considering the long history of wire rope haulage and the large number of rope applications, it is a tribute to wire rope makers and to mine maintenance engineers, throughout the world, that not many serious accidents have occurred because of failure of wire rope. However, when a...

Jan 1, 1965

By Jarrett. K. M.

Nobody has, as yet, made a perfect machine. Therefore, when a machine is operating and functioning as it is designed to do, there is always some vibration present. This is easily and simply measurable with present-day equipment and any increase in the amount of vibration will indicate a potential failure. When an increase is noted, vibration analysis can pinpoint the cause of the potential failure and remedial action can be taken before an unscheduled shutdown is necessary or a breakdown occurs.

Jan 1, 1972

By De-qing Zhu, Feng Zhang, Jian Pan

Sintering performance of a series of sinter blends with high ratio of limonite was investigated. The metallurgical performance and mineralogy of product sinter were also examined. The results show that good sintering performance could be obtained when the ratio of limonite was below 43% in the blends of iron ore fines, while good microstructure and metallurgical properties were achieved under optimum sintering conditions. In contrast, sintering performance will rapidly deteriorate when the ratio of limonite is elevated up to 63% in the blends.

Mar 1, 2017

By Olivia Gamache

When working in remote and extreme environments, projects are faced with new challenges for engineering and project execution. This is heightened when also working in countries with a developing environmental regulatory framework, small skilled workforce available for recruitment, and minimal infrastructure such as power, roads, and water. There is an increasing realization that social and environmental aspects need to be built into project execution. Giving proper attention to these issues during project development and execution, and maximizing opportunities is an ongoing challenge.

May 1, 2013

By Li Changgen, A. Bahr

The adaptability of pneumatic flotation cells for the flotation of sulfide ore and the conditions for sulfide ore flotation in pneumatic cells were investigated. The advantages of pneumatic flotation cells over mechanical flotation cells, as well as flotation columns, for the flotation of sulfide ore were demonstrated. Test results indicated that the Cu grade and recovery for concentrates obtained when using the pneumatic flotation cell were 1 % to 2% and 4%, respectively, higher than those obtained when using the mechanical flotation machine.

Jan 1, 1993

By Colquhoun L

Flooding velocities were measured in a laboratory column (96 mm 4) provided with both bottom and side air entry Packings used were 6 mm glass rings and spheres and -16 +8 mm coke. Results showed that when air was introduced through side nozzles flooding velocities were much higher than those obtained when air was introduced at the bottom of the column. Significance of the results and application to blast furnace flooding is discussed from the viewpoint of assymmetric gas flow.

Jan 1, 1975

By David J. Kruse

Accurate field measurements are essential when validating a conveyor design. They are fundamental in determining a conveyor's behavior, its long-term maintenance requirements, and the life expectancy/ condition of the installed equipment. Field measurements are also invaluable in forensic engineering, particularly when vital equipment has failed This paper will discuss a wide variety of data acquisition equipment, field measurement techniques and accuracies achieved State-of-the-art, custom designed monitoring equipment, as well as, ''08-the-shely instruments and sensors, will be discussed.

Jan 1, 2004

By Clarence R. Zink

A problem has always existed in deep and fast drilling situations such as coal overburden drilling, or when drilling with a tight annulus, such as 9 7/8" bits and 8 5/8" pipe. This problem is the difficulty experienced by blasthole bit and blasthole drill rig manufacturers to attain large jumps in bit and drill rig productivity through bit and rig design, when drilling in these specific situations. In other drilling situations, these large jumps in productivity have been easily attained.

Jan 1, 1998

By David Weidner

Public relations, regulatory compliance, determination and implementation of pre-blast inspections, and accurate blast monitoring data are all essential components when conducting blasting operations for a large scale, high profile, urban site development. By working closely with the contractor, an independent vibration consulting firm can provide the commitment of time, energy and resources to tie all of these elements together. When this comprehensive approach is properly implemented, problems often associated with projects of this magnitude can be almost completely eliminated.

Jan 1, 2001

By Joshua A. Bennett

"Lawsuits where owners allege their property has been damaged by nearby blasting routinely costblasting companies, explosives engineers, and others in the field both time and money. When ownersfeel the vibration of a blast, they immediately begin to look for damage and usually find cracking thatwas, in fact, present prior to the blasting occurring. When those owners begin to talk to their neighbors and legal counsel, blasting entities suddenly have multiple lawsuits being filed as a result of the same blast."

Jan 1, 2016

By M. Shriwas, F. Calizaya

"Controlled recirculation may be considered as a beneficial means in mines of cold climate, where heating of air is required, and in deep or extensive mines, where cooling of air is required. Controlled recirculation can be designed by proper sizing of the booster fans with respect to main fan. Intuitively, it seems that the buildup of methane at the face will cease when a steady state condition is attained, and also that, at that same time, the maximum concentration at the face will remain same as in the return air. This supposition is proved by mathematical analysis that considers uniform mixing of methane in air in successive cycles of recirculation. This study includes two scenarios to show the effect of controlled recirculation on methane concentration in a sample network. Firstly, when recirculation crosscut exists near the working face; secondly, when recirculation crosscut exists away from the working face. The later scenario shows lesser buildup of methane concentration than the former one. INTRODUCTION The controlled recirculation is designed purposefully to allow a partial fraction of used air that increases the air velocity due to increased quantity of air and consequently allows effective dilution of contaminants to improve local ventilation condition at the working face. It can be designed by proper sizing of booster fan with respect to main fan in a ventilation network. Controlled recirculation may be categorized as crosscut, in-line or combined system based upon the configuration of the booster fan locations in a district ventilation network. Research on controlled recirculation has shown numerous benefits of controlled recirculation especially in deep or extensive underground mines, where further heating or cooling is required (Calizaya 1990; McPherson 1993 and Jones, 1987). However, fear of buildup of concentration has misled the mining communities to view the controlled recirculation as a hazard and deprived the mining industry to derive benefits from recirculation. Intuitively, it seems that the buildup of methane at the face will cease when a steady state condition is attained, and also that, at that same time, the maximum concentration at the face will remain same as in the return air. This supposition is proved by mathematical analysis that considers uniform mixing of methane in air in successive cycles of recirculation. This study includes two scenarios to show the effect of controlled recirculation on methane concentration in a sample network. Firstly, when recirculation crosscut exists near the working face; secondly, when recirculation crosscut exists away from the working face. The later scenario result shows the less buildup of methane concentration than former scenario result."

Jan 1, 2016

By Shantaliu S. Shevade, Muhammad M. Rahman

"This paper presents a systematic analysis of fluid flow and heat transfer processes during the magnetic heating of the substrate material. Heat is generated in the substrate material when a magnetic field is imposed due to change in orientation of the molecules. As a result, the substrate temperature rises. The i;tudy considered microchannels with rectangular and square cross section with heat generation in the substrate due to imposed magnetic field. The results computed were for Gadolinium substrate and water as the working fluid. The purpose of this study is to explore the transient heat transfer coefficient when the fluid is circulated through the substrate via microchannels. Equations governing the conservation of mass, momentum, and energy were solved in the fluid region. In the solid region, heat conduction was solved. From the simulation results, plots of Nusselt number and heat transfer coefficient were obtained over the length of the channel. A thorough investigation for velocity and temperature distributions was performed by varying channel aspect ratio, Reynolds number, and heat generation rate in the channel. It was found that the peripheral average heat transfer coefficient and Nusselt number is larger near the entrance and decreases downstream because of the development of the thermal boundary layer. With the increase in Reynolds number, the outlet temperature decreased and the average heat transfer coefficient increased.IntroductionMagnetocaloric effect (MCE) is the heating or cooling of the magnetic materials due to varying magnetic field. The effect was originally discovered by Warburg. Magnetocaloric materials store heat energy in the way the atoms vibrate and in the way electrons spin within each atom. More heat energy increases the vibrations and also makes the spins more random. When a strong magnetic field is applied to a magnetic material, the magnetic moments of its atoms become aligned making the system more ordered. The more ordered material has lower entropy and compensates for the loss by heating up. When the magnetic field is removed, the magnetic moments return to their random directions, entropy increases and the material cools. Gadolinium is a magnetic material that exhibits high temperature rise during adiabatic magnetization around its transition temperature of 295 K. It has been experimentally observed that adiabatic temperature rise increases with magnetic field strength and can be as high 20 K when a magnetic field of IO T is applied. Thus magnetic field, when applied to a microchannel heat exchanger, causes temperature change in the magnetic material. The fluid flowing through the channel gets cooled or heated due to this adiabatic temperature change."

Jan 1, 2004

By T. T. Read, F. C. Houghten

"The bad effects upon the health and output of miners that result when the ventilating current in a mine lacks sufficient cooling power have been described by Harrington and Sayers in a previous report (1)*** The normal temperature of the human body is about 98.5°F. and whenever work is done by the muscles, indeed even when sitting still, the normal bodily processes generate heat which must be given off, otherwise the body will become overheated and a number of bad effects will be produced. If it were possible to so enclose a man that he could continue to breathe and no heat could escape from his body he would die within a short time. In a series of experiments made at the Pittsburgh Station of the Bureau of McConnell and Houghton (2) found that a dry-bulb and a wet-bulb temperature of 112.5°F could he borne for only 35 minutes, even when the subject was at rest. A wet-bulb temperature of 100.4°F (dry-bulb 157°F) could only be tolerated for 45°F minute. Under such conditions the bodily temperature rises as much as 45°F above normal and the pulse is accelerated. Very uncomfortable sensations are felt when the pulse rate exceeds 135. The human body, like any other internal combustion engine, must be cooled in order to function properly.Under ordinary circumstances the air surroundings people is enough coder than themselves to permit this heat generated within the boiy to be river off with¬out difficulty. At higher temperatures, or when the rate of work, with its corresponding generation of heat is high, the body can not throw off heat fast enough, so it begins to sweat and the evaporation of the sweat cools the body. But the results of the experiments cited above indicate that in still air, even with the body at rent, it can not adjust its temperature when the air is above 90° wet- bulb. J. S. Haldane (4) says ""at a wet-bulb temperature of 60°F the actual amount of work done by the miner begins to fall off; as the wet bulb temperature rinse farther the work Bona gradually diminishes to the vanishing point. Then the temperatures indicated by the wet-bulb exceeds 85°F hard work in a mine seems hardly or the commercial working of a mine the wet-bulb thermometer should not in generaI, be allowed to rise above 80°F, unless perhaps where there it a good current."

Dec 1, 1923

By H. Foster Bain

AFTER all, mineral sanctions are not a measure of peace, they are a measure of war, and we must regard them as such. We have had two examples now in the world-first, Italy, and secondly, Japan-where we have applied sanctions. When we got ready to apply sanctions to Italy that would hurt, they went to war. In the Far East, when we applied sanctions against Japan, in the latter part of 1941, there was a quick reaction, and the Japanese bombed Pearl Harbor.

Jan 1, 1944

By R. L. Grant

[Detonators are used to explode permissible explosives, dynamites, or other high explosives. This explosion or detonation is brought about by the energy which is liberated as a combination of concussion and heat when the detonator is fired. In Other words; "The detonator is the key which unlocks the energy of a high explosive" (8)4. Being sensitive and latently dangerous, detonators must meet two primary requirements: They must be safe to handle and must detonate when desired, thereby imparting detonation to the explosive charge.]

Jan 1, 1941

By L. C. Raymond

Why, in an age when natural resources are available on a scale heretofore unknown, and when there is an unprecedented need for them to be developed, have would leaders been unable to find solutions which world concert the under-developed nations into developing nations? With investments in natural resources declining relative to world needs, it is necessary to reverse this senseless trend. This article is an examination of the paradox based on worldwide aspects of the mineral development field, and suggests a possible solution.

Jan 8, 1964

By Morrison R. D

This paper describes major events in the design, construction, camtissioning and operation of the Elura concentrator. It covers the period fran September, 1974 when laboratory testwork on drill core cotmenced to March, 1983 when the concentrator catmenced operation on run of mine ore following successful completion of initial ccnmissioning tests. The concentrator was designed to treat 1.1 million tonnes of lead-zinc-silver ore per year with a plant availability of 89 per cent. This treatment rate has been achieved for test periods.

Jan 1, 1983