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By W. W. Culter

"This paper is the outcome of thorough investigation into the value of the previous methods used for deriving production decline curves. It is highly important that methods be employed that are fundamentally sound and also practicably applicable. Six methods commonly used were studied. Some of these were found to be fundamentally in error; some save reliable curves but involved much work and time in the preparation; others gave reliable curves with less time and effort.It was found that of the methods previously employed the ""family curve"" method described in Bull. 134 Amer. Inst. Feb. 1918, pp. 499-500 by Lewis and Beal, was probably the most satisfactory. The now method given in this paper ploys the same principles as the ""family curve"" method, but is mathematical instead of graphical,The engineer and the oil man should carefully boar in mind both the use and the limitations of the average production curve such as is derived by the ""family curve"" method or other methods mentioned. Estimations of future productions or of underground oil reserves of a particular tract or well should be made from the production records of the tract or the well itself wherever such records are satisfactory. The use of the average curve of a district or field should be applied only to those properties or wells where there are not sufficient data to construct individual or tract production records, or where the productive life so short that a satisfactory individual record can not be obtained."

Jul 1, 1920

By Oliver Bowles

"A Product from Mica Mines.Mica commonly occurs in pegmatites which consist of large crystals of feldspar and quartz, mica constituting but a small proportion of the total rockMuch of the feldspar thus thro n out during the process of mining is pure and of high quality, end the Bureau of Mines has suggested that much of it could be utilized for ceramic purposes. Encouragement is given to such utilization by the fact that several mines now worked for mica were formerly operated for the production of feldspar. ""'here mines are not readily accessible to railroads feldspar utilization might not be feasible, for it is a much lower priced product than mica and cannot therefore bear as heavy transportation expense. '""here mines ire located close to railroads, however, such utilization would tend to reduce the cost of mica mining, and at the same time assist in the solution of the waste disposal problem.The Bureau has recently been informed that some of the feldspar from mica mines near Spruce Pine, N.C., is now being sold and shipped away. An extension of this by-product industry is to be recommended.A Mica Deposit in New York City.The Bureau recently received a mica specimen obtained from a. building excavation at 157th St. and Riverside Drive, New York City. The specimen was about 2 by 4 inches in size, and fairly clear though containing numerous hair cracks. It was obtained only 7 or 8 feet below street level. At greater depth and with more careful methods of excavation material of much better quality might be obtained. The material submitted could be used for mica washers but not for sheet mica. It is stated by an official of a prominent mica company that many such fragments are obtainable in this locality and the possibility of the occurrence of a good mica vein is thereby suggested."

Jun 1, 1920

By James E. Mauser

This report deals with the investigation of a continuous process for producing pure zirconium. It covers the construction, operation, and maintenance of the semicontinuous reactor. The report covers a study of test variables, such as reactor temperature and reluctant charge weights, and evaluates the results, such as billet metal hardness, residual billet salt content, and suitability of a purified billet as a consumable electrode for arc melting. The purpose of this project was to develop an inexpensive and continuous process for producing pure zirconium. The process developed, termed the semicontinuous reactor process, produced billets of compacted zirconium sponge. The metal was produced by reducing zirconium tetrachloride with sodium and magnesium beneath molten byproduct salt. Hydraulic rams at each end of a vertical reaction tube compacted the sponge and ejected it as a billet. These billets were purified by heat under vacuum to remove entrapped salt. The goal was to utilize the purified billet directly as a consumable electrode for arc melting.

Jan 1, 1961

By Robert L. Marovelli

The thermal conductivities of six rocks were measured by the transient line source method over the temperature range of -850 to 1,500° F. Close-fitting ceramic probes were used in 0.065-inch-diameter holes drilled through 5-to 6-inch-thick rock specimens. Taconite, granite, quartzite, and basalt were used in the tests. The method yields absolute data and is applicable to both laboratory and in situ measurements.

Jan 1, 1965

By R. H. Nafziger

As part of its program to help decrease the dependency of the United States on foreign imports of nonfuel minerals and to devise technology for the efficient and economic use of domestic resources, the Bureau of Mines smelted and sulfation-leached an ilmenite from northern Minnesota. The objective was to assess the feasibility of preparing chlorination-grade titanium feedstock. The concentrate was smelted with woodchips, coke, and soda ash in 91-kg-and 1-metric ton (mt)-capacity electric arc furnaces to form Ti-rich slag and commercial-grade pig iron. The slag contained from 67 to 77 wt pct titanium oxides and from 1.8 to 7.2 wt pct iron. Sulfation occurred in a 4.5-kg/h moving-bed reactor using S02-air mixtures at temperatures of 8000 to 8500 C to form soluble salts of the Ca, Mg, Mn,and Na impurities, which cause plugging of fluidized-bed chlorinators. Subsequently, the sulfated slag was leached in acid to remove the soluble sulfates. The final product from small-scale testing contained up to 95.5 wt pct Ti02, a minimum of 0.6 wt pct Fe, and a minimum total of 0.3 wt pct of the four impurities of interest. The final product meets charge specifications for chlorination. However, more large-scale testing is necessary.

Jan 1, 1987

By John Nagy, Austin R. Cooper

Information is presented on the pressure and rate of pressure development during a dust explosion . The data were obtained in laboratory studies in a 75- cubic inch vessel with mineral , agricultural and chemical dusts . The factors investigated include dust concentration , oxygen concentration of the atmosphere , admixed inert powder , and admixed moisture . Information is given also on the effects of these factors on the composition of the atmosphere after the explosion .

Jan 1, 1964

By Richard D. Graves

Pitch from low-temperature carbonization of bituminous coal was hydrogenated at cracking conditions in a continuous bench-scale unit to produce low-molecular-weight oils and tar acids. The pitch contained 15.6 pct benzene-insoluble material, 4.0 pct hexane-soluble oil, and 80.4 pct asphaltene by weight. At 475° C, 7,500 psig, and 1.5 hours residence time, hydrogenation products, based on the weight of pitch, were about 36 pct oil boiling below 325° C, 24 pct hexane-soluble heavy oil, 17 pct asphaltene, 1 pct benzene insolubles, and 12 pct hydrocarbon gases. The yield of tar acids boiling below 250° C was 4.3 pct, and the yields of C6 to C8 paraffins, naphthenes, and aromatics were each less than 1.0 pct. The yield of tar acids was within the range of yields obtained by hydrogenation or high-temperature carbonization of bituminous coal (2 to 5 wt pct). Yields of oil boiling below 325° C increased with increased residence time or temperature. There was little or no effect of residence time on yields of alkali- soluble material which contained tar acids. Yields of hydro-carbon gases increased markedly with an increase in temperature from 475° to 500° C. Lowering the hydrogen pressure to 4,500 psig resulted in yields similar to those obtained at 7,500 psig.

Jan 1, 1962

By Harold L. Rhodes

Vapor-liquid equilibria data for 65-34-1 and 25-27-48 mole percent helium-nitrogen-methane mixtures are presented for 12 temperatures from 76.5° to 164° K and pressures from 100 to 1,200 psia. These data were obtained in a windowed phase equilibria cell equipped with a vapor recirculating pump. Isobaric and isothermal K-values are plotted for both mixtures. Two isometric plots are included.

Jan 1, 1972

Despite the strange names given to its parts, the eye is not a very complicated organ. If you think of the eye simply as a detector of light, you will be able to understand the mechanics of central vision, peripheral vision and adaptation described below. These three processes of seeing are basic, not only to mining, but also to everyday activities. A number of simple experiments are described In this chapter to demonstrate different types of seeing processes. Try the experiments. They really make the point. Light rays reflecting from objects enter the eye through a lens and fall on the back surface called the retina. The retina 1s lined with millions of tiny light sensors called "rods" and "cones." These sensors, in turn, are connected to the brain by the optic nerve.

Jan 1, 1976

By William O. Vanderburg

This paper describing the methods and costs of milling scheelite ore at the Silver Dike concentrator of the Nevada-Massachusetts Co., Inc., is one of a series being prepared by the Bureau of Mines. In the Silver Dike mill tungsten ore which contains about 1 per cent of scheelite is treated at the maximum rate of 45 tens per 24 hours by tabling followed by magnetic separators to clean the table concentrates. Unusually high-grade concentrates are produced which average between 70 and 75 per cent of W03.

Jan 1, 1932

By I. S. Solet

This study, of the liquidus temperatures and densities of molten alloys of zinc and aluminum was made as part of a broader investigation on refining of scrap aluminum. One of the methods of refining involves the separation of liquid and solid phases by gravity segregation and by filtration. More accurate data were required on the liquidus temperatures and the densities of molten' mixtures of the metals than were available in the technical literature. New data on the liquidus curve were obtained by thermal analysis. The new temperatures are, for the most part) somewhat higher than those reported previously by other investigators. The density of molten mixtures of zinc and aluminum were found to be less than would be calculated by assuming that the two metals occupy the same respective molal volumes in solution as they do as pure metals.

Jan 1, 1949

By Terry S. Cory

This report covers magnetic field strength measurements vs range and frequency in low-medium coal mines. Both quasi-conductor-free and conductor-proximity areas were investigated. The program covered 5 mines, 4 seams, 6 measurement sets, and 3 geographic areas. The results have been summarized in terms of maximum communication range expected per seam and noise condition. Scatter gain is further explored as a simple measure of energy coupled to conductors.

Jan 6, 1978

By G. E. McElroy, D. Harrington

The use of shall electrically- driven fans , in conjunction with air- pipe of various diameters is becoming of increasing importance for the ventilation of working places in metal mines through which the general ventilating currents can not be coursed . It will probably continue to increase in importance since the concept that air motion is the most important factor in maintaining comfort in hot ( above 80° F . ) working places is more generally accepted , and as the inefficiency and greater expense of attempting to ventilate such places with compressed air is recognized . Managers of large properties can afford to experiment with fan- pipe installations until types are found that meet their conditions , but managers of shall properties , unless forced to it by extreme conditions , prefer to wait until they can obtain data sufficient to guarantee at least a measure of success from such installations . At present , such data , even in part , are available to only a few (mainly fan manufacturer's representatives , consulting ventilation engineers , and ventilatin engineers employed by large companies ) , and important recent developments are mostly of a confidential nature . One large metal - mining company cooperated with a fan manufacturer in some extensive experimental work on small blowers and found that instead of using stock fans , considerable power economy could be effected and equal quantities of air delivered by use of or 2/3 width fans with small motors rather than using stock fans and larger motors ; it was also found advisable to adopt certain sizes of tubing for certain lengths of run . In fact , many important facts were ascertained in this study , and it is now promised that they will soon be given to the public . It is true that a certain amount of data on industrial installations are available , but such data are only in part applicable to metal -mine conditions , because , until recently , little attention has been given to ventilation in metalmines , and the conditions encountered usually require a greater length of pipe , a more temporary type of construction , and closer attention to temperature control than the ordinary run of industrial installations demands ..

Feb 1, 1922

By J. Litsenberger, T. E. Marshall, P. R. Coyle, L. J. Prosser, A. T. Iannacchione

For the first time in an underground stone mine, the relationship between roof movement and microseismic emissions was examined in conjunction with two distinct roof fall areas. As roof monitoring increases in acceptance and monitoring technology advances, the goal of providing reliable roof fall detection systems to enhance the safety of underground mine workers moves closer to reality. Instrumental to reaching that goal is the ability to interpret accurately and completely roof movement and microseismic emissions, which can serve as precursors to roof falls. This paper examines the capabilities of convergence and microseismic monitoring systems to better understand roof rock failure mechanics and to anticipate roof falls. An understanding of how these techniques are used and how they interact with each other is critical in developing the most effective ground control strategy for our nation’s mines.

Prevent the propagation of a fire and control the spread of smoke and toxic gas in underground mines. Approach A fire door suitable for large openings in underground noncoal mines and providing protection for openings requiring 11/2 hours of fire resistance, a 250°F maximum temperature rise, and high pressure differentials was de-signed, laboratory tested, and in-mine tested. How It Works The door is a double-acting swing type. Its two panels. connected by an overhead linkage, open in opposite directions. Consequently, high pressure differentials across the door have little effect on the force required to open and close the door. The door is constructed of 14-gauge sheet steel skins welded to both sides of a 5-inch-wide steel channel frame. The frame is rein-forced with 5-inch-wide steel channels in a horizontal and diagonal pattern. The voids between the reinforcing members are filled with a ceramic fiber insulation material to limit the surface temperature rise of the unexposed side of the door during a fire. A fire -resistant neoprene-coated fabric is used to seal around the edges of the door panels. The door is opened and closed by an air cylinder, attached to the over-head linkage and operated by lanyards on either side of the door. The door design includes an optional airlock manway for drifts of adequate width.

Jan 1, 1983

By N. S. Dalal, A. H. Hoffman, X. Shi, D. E. Banks, J. K. H. Ma, Y. Rojanasakul

Excessive production of reactive oxygen radicals by alveolar macrophages is proposed to play an important role in oxidative lung injury. A major product of oxygen radical formation is the highly reactive hydroxyl radical (•OH) generated via a biologic Fenton reaction. In addition to its known ability to induce lipid peroxidation, recent studies have suggested that the •OH may exert its cytotoxic effect through the alteration of [Ca2+], homeostasis. To test this potential mechanism as well as to investigate the relationship between •OH and Ca" overloading in cytotoxic injury, isolated rat alveolar macrophages were exposed to externally generated radical system, H2O2 (0.01 to 1 mM) and Fe (1 mM) and their [Ca2+] levels and cell injury were monitored using quantitative fluorescence microscopy with the aid of the specific Ca" indicator, Fura-2, and membrane integrity indicator, propidium iodide. Electron spin resonance measurements using the spin trap 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) confirmed the production of the .OH radical by this system. Upon the addition of the radicals, the macrophages displayed a rapid initial rise in [Ca2+] which was followed by a slower but more pronounced [Ca2+], elevation that reached a level 3 to 5 times higher than the basal level. This process preceded cell death as evident by nuclear propidium iodide fluorescence. Depletion of extracellular Ca" inhibited both the [Ca2+], response and cell injury. Preincubation of the cells with the Ca" channel blocker verapamil or .0H radical scavenger mannitol similarly inhibited the [Ca2+], rise and loss of viability. Firefly luciferase assay of cellular ATP content demonstrated that the alterations in [Ca2+], following .0H treatment preceded the depletion of ATP. Changes in membrane potential caused by Na* substitution with K* had no significant effect on either the unstimulated or stimulated [Ca"], levels. Taken together, these measurements indicate that .OH-induced injury in alveolar macrophages is associated with the alteration in [Ca2+], homeostasis. The mechanism of •OH-induced [Ca2+] loading is not due to nonspecific membrane damage or energy depletion, but mainly due to an increase in Ca2+ influx through Ca2+ selective channels. This Ca2+ over-load state as well as energy depletion caused by the oxidant may activate certain cellular degradative processes leading to cell injury and death.

Nov 1, 1995

By J. W. Paul

"The economic features of coal mining must take into account the drain on the man power. Study over a recent 5-year period reveals an average yearly loss of 2,125 underground men, of whom 1,182 are killed by falls of roof and coal, and according to recent data compiled by the Bureau of Mines it is estimated that 54,000 men sustain lost—time disabling injuries from the same cause.Under normal activity of the mines approximately 50 lives are taken by falls of roof during every 10 days the mines are operated, or 5 persons are killed per day, which, at a compensation charge of $5,000 each, amounts to $25,000 per day. Add to this the similar number killed by causes other than by falls of roof and we have $50,000 as an approximate daily fatality charge for each day the mines operate. On the basis of 200 working days per year, this amounts to the alarming figure of $10,000,000 annually. An investment at 5 per cent to yield this amount would require $200,000,000, which is equivalent to a capital investment of $0.40 per ton of coal, produced annually, on the basis of 500 million tons. These figures apply only to fatalities for which a fixed or stated amount is paid for compensation and do not include the compensation and hospitalization paid for the approximately 103,000 upon whom idleness is enforced by a lost-time disability injury. In one State having an annual production equal to approximately 30 per cent of the total bituminous production of the United States, the most recent data shows that for each fatality there are eight serious injuries causing 60 days or more lost time. The frequency rate of accidents for that State is less than the average for the United States, and so a conservative comparison may be made by using the figures of that State in estimating the total serious injuries, which gives 16,000 as losing 60 days or more. The average number of underground employees in the coal mines of the United States for the past 10 years has been approximately 570,000; the annual underground fatalities amount to approximately 2,000 and non-fatalities to 108,000, or a total of 110,000, which means that one out of every 5.17 employees ,or 19.3 per cent, receives an injury which results in either a fatality or a lost-time disability; this figure in a little over five years will reach a number equivalent to 100 per cent of all underground workmen. Against this is the record of many miners who have worked 25 years or more without a lost—time disability injury, indicating that coal mining is not necessarily productive of injury or death to workers.In the matter of falls of roof, it is found that 85 to 87 per cent of all fatalities occur at the working face, face of a room or entry, or in pillar work. It is at the working face that the greatest roof hazards are encountered, and when about 75 per cent of the underground employees spend approximately 90 per cent of their working hours at the face, it is logical that there is where injury is most likely to occur.Although the roof hazards may vary in different beds of coal, experience has proved that roof hazards can be successfully controlled in all coal mines, essentially regardless of the character of the roof if constant care and attention are given by the management and employees in applying the principle of safety. In almost every mining district some companies maintain an extremely low frequency rate of injury, whereas in the same district with essentially the same roof conditions the opposite is true.A study has recently been made of a number of reports upon fatalities in one district of one of the principal coal—producing States and it showed that 50 lives had been lost at 23 mines as the result of falls of roof or sides. These reports were made by the mine officials, safety engineers, and safety committees and an attempt was made to give both the cause and the person or factor responsible for the fatality. A summary of the items of responsibility is as follows:"

Feb 1, 1932

Reduce injuries caused by slips and falls from large haulage vehicles. Approach Replace the flexible-cable or chain-type lower ladder steps, with steps that extend closer to the ground and do not sway when stepped on. Modify dimensions of entire ladder to new industry recommendations. How It Works New lower ladder steps are supported by side pieces made of pretensioned, solid-wound, coil springs fabricated from high strength steel. Unlike conventional crash-resistant steps, which flex or swing freely when stepped on, the spring supported steps can maintain the same inclination as the fixed upper portion of the ladder while supporting an average-weight operator. The steps are also highly resistant to collision damage because they yield on impact if rammed into obstructions such as rocks or berms. See photograph.

Jan 1, 1980

By Liming Yuan

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Jan 1, 2009

Great strides have been made in recent years to reduce the disaster potential of underground mine fires. However, mines can still be caught unprepared for a fire emergency. Fires can grow too large before they are detected, warning systems can be too slow and uncertain to reliably signal the danger, and suppression systems can be inadequate to extinguish the flames. New mining systems and equipment may create unanticipated fire hazards, and new materials may generate highly toxic combustion products. This report contains papers that summarize recent significant developments from the Bureau of Mines mine fire protection research program relating to these problems. Certain of these findings are also applicable to surface mining operations. The papers fall into the general categories of fire detection and instrumentation, fire warning, fire suppression, diesel equipment, spontaneous combustion, and toxicity analysis of combustion products.

Jan 1, 1988