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By J. F. Barkley

The following questions and answers were prepared principally to supply information in answer to general inquiries received by the Bureau from those contemplating the use of propane and butane fuels . Primary or basic information only is covered; this usually gives enough guidance for most inquirers . To those who wish information of the treatise type , the handbook , Butane- Propane Gases , published by the Jenkins Publications , Inc. , 1709 West 8th Street , Los Angeles 14, Calif . , is suggested .

May 1, 1949

By Thomas C. Miller, Rudolph Sporcic

A relatively simple and inexpensive encapsulated hydraulic device has been developed by the Bureau of Mines to facilitate study of coal bumps , and to measure pressure changes in a coalbed as it is subjected to roof loading during mining . Construction of the device and application techniques are described . Preliminary feasibility tests in the laboratory and field indicate that the device responds satisfactorily to pressure changes in coal created by roof loading .

Jan 1, 1964

By Steven E. Mischler

The exposure of mine workers to diesel particulate matter (DPM) and gases is an issue of great concern to the underground mining community in the United States. Approximately 30,000 underground miners are potentially exposed to high concentrations of DPM. In January of 2001, the U.S. Mine Safety and Health Administration (MSHA) promulgated rules setting compliance standards for both underground coal and metal / nonmetal mine workers. As industry works to achieve compliance with these standards, mine operators are looking for feasible methods for reducing DPM concentrations in their mines. In addition, the industry needs methods to accurately measure DPM to ensure that the control strategies they adopt are working successfully. The Pittsburgh Research Laboratory (PRL) of the National Institute for Occupational Safety and Health (NIOSH) conducts research to evaluate control technologies and monitoring instrumentation that can be used to reduce the diesel particulate matter (DPM) exposure of mine workers. An overview of the strategies being utilized in underground US mines to reduce DPM concentrations will be presented. Also, updates on the development of diesel monitoring instruments such as the continuous elemental carbon monitor or the Personal Dust Monitor for DPM measurement will be provided.

Jan 1, 2010

By K. Kar, M. Gautam, J. T. Jurewicz

The 10-mm Dorr-Oliver cyclone has been widely used as a personal sampler for size selective sampling of particles within the respirable range (Dp < 10 gm). Because of their inertia, the particles are unable to follow the swirling flow (outer vortex) within the cyclone. The particles migrate to the bottom of the cyclone, depending on their size, and get trapped into the inner vortex which leads to an eventual blow-off from the top of the cyclone. By measuring the size distribution of the particles in the free stream and in the collected sample, the aspiration efficiency of the cyclone can be calculated. Velocity difference between the free stream and sampling velocity. Inlet orientation, particle impaction and deposition, particle inertia and free stream turbulence result in the departure of the aspiration efficiency from unity and this, in turn, leads to inlet bias. Although the effect of inlet bias on sampling efficiency has been investigated in past, the results lack detailed information and show only some general trend. In this effort, a systematic, in-depth experimental work on the effect of inlet bias on the sampling efficiency has been undertaken using non-intrusive Laser Doppler Anemometry (LDA), Aerodynamic Particle Sizer (APS) and impactors.

Mar 1, 1992

By P. A. Surgeon, R. R. Sayers

It is not the purpose of this report to try to describe all the work done during the past year for the improvement of health or the prevention of illness among miners , but to call attention to a few of the more outstanding investigations in which progress has been made . Among these , the investigations on the physiological effects of carbon monoxide , dust and ventilation , and temperature and humidity will be discussed . Carbon Monoxide . During the years 1920 and 1921 , much more work has been done on the various A survey phases of carbon monoxide than has been carried on for a number of years . of carbon monoxide poisoning in the American steel works , metal mines , and coal He conmines was made by Dr. Henry S. Forbes , of the Harvard Medical School . ** cludes from his survey that late after- symptoms following acute severe gassing rarely occur , and that almost always there is evidence of pre - existing pathological conditions when such effects do appear . He further states that he found no evidence of cumulative harmful effects resulting from frequent exposure . Dr. Forbes , Dr. Forbes , assisted by Louise Hompe , made a laboratory investigation in which anesthetized animals were exposed to carbon monoxide , illuminating gas , and benzol *** . The investigators conclude that , under the conditions of their experiments , there is no change in the coagulation time of the blood . It has been stated by many investigators that the blood of those affected by carbon monoxide does not clot as quickly as normal blood . While the investigation referred to above may not cover all the conditions , it is a valuable contribution to the subject as it indicates that the small hemorrhages found in the membranes covering the central nervous system , abdominal organs , etc. , at autopsy of those dying of carbon monoxide poisoning is probably not due to direct toxic action of the gas upon the blood .

Feb 1, 1922

By E. J. Gleim

"Information gathered during recent months by field men of the U. S. Bureau of Mines shows that in one State alone there have been 71 fatalities from electrical causes during the last 51/2 years, of which 55 were from contact with mine trolley wires operated at 250 volts or less, direct current. The 1928 law relating to the guarding of trolley wires in the-mines of this particular State reads: ""All trolley wires carrying a voltage of class 2 must be properly shielded except where the same are at least 61/2 feet above top of rail."" Class 2 voltage is defined as being ""between 300 volts and 600 volts direct current, or 240 volts and 480 volts alternating current."" From this it may be inferred that no guards are required, for 250-volt trolley wires, and the natural conclusion to be drawn is that the lack of guards or shields must be held responsible for these fatalities. To prevent fatalities from this source, it has been advocated that every foot of trolley wire in mines should be guarded. While some such drastic step may appear to be amply justified, a closer examination of the records shows that lack of guards is not entirely responsible but rather that carelessness and neglect in the observance of certain well-established simple rules concerning installation and location of trolley wires must also bear a share in the responsibility. In -other words, if trolley wire is installed carelessly and its maintenance neglected, failure may be expected of any guards that have been put up.There are a-number of factors affecting safety as related to trolley wires in mines, among which the following may be enumerated.1. Installation relative to track and passageways.2. Guarding.3. Maintenance.4. Discipline.Acknowledgment is made to D. Harrington and K. L. Marshall of the safety division of the bureau for assistance given in securing data on cost of installing guards for trolley wires.The statement that fatalities should not be charged in every case to lack of guards is supported by the following example: A man operating a locomotive was electrocuted when the trolley wheel jumped the 250-volt trolley wire and allowed it to sag against his shoulder. He was sitting in the regular place provided in the locomotive, but the wire was 11 inches inside of the rail and only 39 inches above it where the wire touched him, or 11 inches from the roof at a distance of 12 feet from the nearest hanger. The accident occurred between two hangers 44 feet apart, and the trolley wire was inside the rail over the entire distance, being 2 inches inside at one hanger and 10 inches inside at the other hanger. A bolt in the roof indicated that there had been a hanger at one time between the two on the 44-foot span.This example is a violation of good practice in the installation and maintenance of trolley wire. In the first place the wire should have been outside instead of inside the rail. In the second place there should have been at least one intermediate hanger so that the span would not be so great and the sag would be reduced. Furthermore, it is possible that the wire was not taut enough even when the intermediate hanger was in place.To provide a degree of safety for men in the mines certain coal-mining States, recognizing the need, have enacted laws to regulate the installation of trolley wires. These limit the distance that the wire must be kept outside and above the rail. Thus, the 1927 mining laws of Ohio specify that:"

Apr 1, 1932

Improve the strength and other properties of steel alloys. Approach Research by the U.S. Bureau of Mines indicates that steels melted and solidified under high nitrogen pressure acquire yield and tensile strengths that are up to four times the strengths of comparable stainless steel alloys without nitrogen. Fatigue strength, creep strength, and other mechanical properties are also improved. Strengthening occurs by two mechanisms: (1) increasing dissolved nitrogen in the lattice and (2) formation of dispersed metal nitride phases. Nitrogen Alloying Nitrogen alloying of a steel is generally done by introducing metal nitrides during melting of the steel. The concentration of nitrogen is limited to its equilibrium solubility at 1 atmosphere. For face-centered-cubic (fee) iron, that solubility is approximately 0.4 weight percent (wt%). For body-centered-cubic (bee) iron, solubility is 0.05 wt%. This solubility limitation can be overcome by melting the metal in a pressurized vessel. European steelmakers currently have metal-processing systems that can melt and pour tons of steel under nitrogen pressures exceeding 4 megapascals (MPa) (40 atmospheres). They have achieved nitrogen concentrations as high as 1.0 wt% in these (stainless) steels. The tensile strength is approximately twice the tensile strength of similar steels without nitrogen.

Jan 1, 1992

By J. D. Noll

The Mine Safety and Health Administration (MSHA) has promulgated rules to limit the exposure of metal/nonmetal underground miners to diesel particulate matter (DPM). These rules have resulted in many types of control tech­nologies being implemented including diesel particulate filters (DPF). The passive type DPF is the most desirable because it requires little maintenance and it regenerates while the vehicle is operating. One problem with passive DPFs is that many vehicles cannot develop the sustained exhaust temperatures needed to initiate DPF regeneration, and thus it is required that the DPF be catalyzed to decrease the temperature needed for regeneration. In some past studies, such catalyzed filters have been shown to cause an increase in the nitrogen dioxide concentrations in the exhaust, resulting in a potential health hazard. In this study, a lightly catalyzed DPF along with a fuel-born catalyst were employed to help reduce the DPM emissions from a 980F loader used for cleanup in a stone mine. After 30 days of use, the filter continued to regenerate successfully at the exhaust temperatures generated by this loader, substantially reduced DPM concentrations emitted in the exhaust, and did not cause a measurable increase in nitrogen dioxide levels that could be attributed to the device.

Jan 1, 2009

Provide blasting-resistant, quickly reusable stoppings for large mine openings. Approach Stoppings are assembled using roof-to-bottom panels of brattice held together by Velcro seams that peel open when struck by a strong air blast. How It Works The Velcro seam is designed to open when exposed to forces lower than would normally damage the brattice. When the seams partially open, they relieve the blast air overpressure to prevent damage to the brattice panels and their anchoring devices. A stopping is returned to service by reclosing the Velcro seams. To hang a brattice panel, its top is stapled to a board, and wrapped once or twice around it. That assembly is then attached to the roof with bolts. The length of the board should be a foot less than the width of the panel to allow for the sealing seam on each side of the panel. The boards are installed end-to-end in an approximately straight line across the roof of the mine opening.

Jan 1, 1979

By Joseph A. Holmes

The perpetuation of the supply of anthracite coal in Pennsylvania is a national as well as a State problem. Any investigation that shows how larger percentages of this coal may be saved in mining, without excessive cost, and without dangerous subsidence of the overlying surface ground, has a national as well as a local interest. Messrs. Conner and Griffith, who conducted the investigations described in this report largely for the city of Scranton, are consulting engineers for the Bureau of Mines for investigations similar to those they have already made in connection with their Scranton work; and this report is published by the bureau in response to numerous requests, because of the fact that the information it contains will prove useful in the general solution of similar problems in many of the country's coal fields. A study of the accompanying maps will show that the city of Scranton is underlain by 11 separate beds of coal, varying in thick- ness from 2 to 24 feet. It is estimated that before mining opera- tions were begun these beds of coal contained underneath the present city limits of Scranton 600,000,000 tons of coal. The 27 collieries operating within the city limits, working independently of each other, had excavated and removed, up to March, 1911, an aggregate of 198,000,000 cubic yards of coal and accompanying rock, or 3,000,000 cubic yards more than the total amount of material excavated and to be excavated by the United States in constructing the Panama Canal. This fact illustrates something of the magnitude of the problem that the city of Scranton, with the aid of these engineers and of a special commission or advisory board, has undertaken to solve. The excavation has included 177,000,000 tons of coal and 44,000,000 tons of rock and accompanying refuse. This leaves about 420,000,000 tons of coal still to be removed. As a result of other investigations and of experience in adjacent anthracite mines, Messrs. Conner and Griffith and the advisory board of engineers have advised that, as far as may be necessary to prevent dangerous surface subsidence, the spaces remaining beneath the city of Scranton from the excavation of the above-described material should be filled with sand and other materials by flushing or other processes. This operation is expensive, but it is believed to be not beyond the reach of what is practicable, nor in excess of the value of the coal that may be removed and the amount of damages that may result from the caving in of the surface if such a plan is not carried out. No one realizes so fully as do the authors of this report the need of additional tests and other investigations before the data now pre- sented by them can be fully accepted as sufficient for all purposes in the solution of the problem; and it is expected that at some early date a more extensive series of similar tests can be made by the Bureau of Mines under the supervision of Messrs. Conner and Griffith on a larger scale and under a greater variety of conditions. The field examinations made for the Bureau of Mines by N. H. Darton, which are described briefly in a chapter of this bulletin and will be discussed at length in a bulletin to be published later, indicate the extent and distribution of the sands, gravels, and other materials in the Scranton-Wilkes-Barre district available for flushing purposes if further tests indicate their relative merits; and it is expected that the relative merits of these different materials will soon be tested under such conditions as will furnish the desired information.

Jan 1, 1912

By Graham W. Marks, RALPH MILLS, FRANK COSSEY

To determine the focal length of lenses or the performance of lens systems before mounting them permanently , it is desirable to have a device in which one or more lenses can be mounted easily and their positions relative to a light source and screen changed readily . We have designed and constructed such an optical bench and lens holder . The bench is similar to that of Houstoun5/ but has been modified , whereas the lens holder is , we believe , a new design .

Jan 1, 1948

By R. V. Ramani, V. T. Burgos, J. A. McClay

Cost Data Library The data retained in the Cost Data Library is of a semi¬permanent nature in that it is held in storage for immediate use with the program although its contents may require periodic evaluation to maintain it in a current status. The library is composed of six arrays containing both technical and cost data. The following description of the library input system provides the information necessary to maintain an active storage file. Array POWERA: FORMAT (8F10.0) - contains the step groupings of the power rate schedule for power cost computations. Four input data cards are required to fill this storage area. Card Column 1 1 - 10 Demand in Kilowatts for the First Step of the Demand Rate Schedule 11 - 20 Demand in Kilowatts for the Second Step of the Demand Rate Schedule y 41 - 50 Demand in Kilowatts for Fifth Step of the Demand Rate Schedule 51 - 60 Maximum Demand Level for this Rate Schedule 61 - 70 Percent Power Factor for this Rate Schedule 71 - 80 Unassigned 2 1 - 10 First Step Demand Charge, $/Kw 11 - 20 Second Step Demand Charge, $/Kw 4¬ 41 - 50 Fifth Step Demand Charge, $/Kw

Jan 1, 1975

By Gordon L. Kinney

Following a year of great uncertainty, the political situation in Bangladesh improved during 1976. The major problem for Bangladesh remained the high birth rate and crowded conditions. Bangladesh had the highest population density of any agrarian country--over 80 million people in a land area of 144,000 square kilometers, 65% of which is considered arable. The Government, with considerable foreign assistance, was actively encouraging voluntary family planning, and set a growth rate target of 2% per year or less. However, even if the growth rate was reduced to the target level immediately, the population of Bangladesh would nevertheless nearly double within 20 years.

Jan 1, 1980

By M. B. Cooke

In the course of investigation now in progress by the Bureau of Mines into the nature of " gum forming" constituents of gasoline , several gasolines and other petroleum products were heated in a small bomb , and pressures of considerable magnitude were developed . As the Bureau has received many inquiries for data showing the pressure that may be developed in a still when gasoline or other oil is subjected to elevated temperatures , it was thought advisable to record the pressures observed at various temperatures in the course of this work . data were merely a by- product of the main investigation . These Gasoline and similar products are very complex mixtures , and it is difficult to determine accurately the true vapor pressures , hence the vapor pressures of the oils used in these tests have not been studied in detail , but the data obtained may be taken as representative of the pressure- temperature relations of the various oils in commercial work.

Jun 1, 1922

By C. L. Severy

On the Pacific coast during World War II, a tremendous ship-building industry was developed, Early in the war it became impossible to obtain in- got or steel scrap for ship ballast. Magnetite, an oxide of iron, was sub- stituted as it fulfilled the requirements of weight for available space in the ships. Consequently, a new use for the western magnetite was rapidly developed.

Jan 1, 1948

By W. D. Ryan

The American public has at all times been prone to discuss important questions that call for consideration and adjustment. Debatable subjects upon which sides may be taken always receive unusual prominence, but other questions equally important may be neglected. The real "paramount issue," calling for remedial action, is the ever-increasing number of deaths caused by preventable accidents. This matter demands the attention of the entire American people; the importance of accident prevention can not be overemphasized, and in many phases of American life, especially among the mining and allied industries, far too little real attention has been given the importance of conserving life and limb by accident prevention. ACCIDENTS COMPARED TO WAR AS A CAUSE OF DEATH Harry T. Hoffman, Wyoming labor commissioner, writes the following: It is one of the peculiar complexes of this rapidly moving age that we all stand aghast at the horrors of war and view with appar- ent indifference the greater havoc of industrial peace. Did you ever stop to think that approximately twice as many people were killed by accidents in the United States in 1929, as there were American soldiers killed in the entire period of the World War? Every employer and every worker should be thoroughly aroused over the tremendous toll levied against industrial forces by accidents which are largely preventable and develop a faith in safety efforts that will fire them with a zeal as pronounced as that of their religion or their patriotism. Let us remember safety-first to the end that the workman shall live to enjoy the fruits of his labor; that his mother shall have the comfort of his arm in her age; that his wife shall not be untimely a widow; that his children shall have a father; that crip- ples and helpless wrecks who were strong men shall no longer be a by-product of industry.

Apr 1, 1931

Reduce dust exposure of longwall shearer operators by keeping them upwind of the primary cutting drum. Approach Use a different coal cutting sequence by cutting from headgate-to-tailgate, making the cleanup pass from tail-gate-to-headgate. How It Works The cutting action of the shearer drum is usually the primary source of respirable dust at longwall shearer faces. Dust exposure of the shearer operator is deter-mined by his position relative to the lead drum, which is normally in the raised position taking a full sump. On long-wall faces where the cut pass is taken from tail-to-head, against the primary airflow, the shearer operators must remain at their controls, on the return-air-side of the primary dust source, to maintain proper control. A simple method to lower shearer operators&apos; dust exposures is to extract the primary coal from head-to-tail, thus positioning the operators up-wind of the lead cutting drum. The bottom coal is then cut, and the floor cleaned by the trailing drum during the tail-to-head cleanup pass. This sequence places the primary dust source, the cutting action of the shearer drums, on the return-air side of both shearer operators, except when cutting out at the longwall headgate.

Jan 1, 1984

By W. D. Ryan

Industry must be made to realize that "Safety First" means just that - safety first. The miner must realize that safety first takes precedence over earnings. The employer must realize that safety is the first consideration, and is not to be subordinated to profit-making. Neither employee nor employer is justified in adopting the principle of safety first with reservations; that is they will practice safety first only so long as they think that it does not interfere with earnings or profits. This paper proposes to demonstrate that suberdinating safety to possible profit is short-sighted and that over an ex- tended period of time it dres not result in increased profits or earnings. An employee through disregard of safe practice may receive an injury that will cause him a loss of earnings if, indeed, he is net killed or permanently in- capacitated. If permanently incapacitated any compensation he may receive is very likely to be wholly inadequate as compared with probable earnings if the accident had not cccurred. The employer, upon his part, will find that the burden of compensating his injured employse will far exceed the outlay of money necessary to maintain a reasonable program of safety in his mine or plant. The mine foreman is one of the most important factors in the matter of mine safety. A vigilant and competent mine foreman, once he has established the confidence of the employees in his ability as a foreman, can be of invalu- able assistance in promoting mine safety, for through him and his assistants the employees may be made to cooperate. Every employer should remember, then, that the soluction of the foremen and their assistants is one of the most important matters connected with the work of establishing the maximum amount of safety in his mine. Everyone connected with the mining industry must be made to realize that there is to be no back-sliding and no let-up in safety work; that no matter how dry and tedious the routine may seem it is absolutely essential and justi- fied for both humanitarian and economical reasons. Efficient safety effort pays dividends in actual cash to both employer and employee. About 50 per cent of underground accidents in coal mines take place at the working face where the miners dig and load the coal. Approximately 17 per cent of coal-mine fatal accidents are the result of underground haulage. Face and haulage accidents can and will be reduced materially if the individual miner takes all precautions necessary to protect himself and if the management

Jun 1, 1930

To expediate the transfer of technology from Bureau laboratories into new products and processes that enhance the economic competitiveness of the U.S. mining and minerals industry in world markets. Background The U.S. Bureau of Mines and various members of the industry are concerned about the current technology challenge to the minerals industry in the United States. They arc working together to delineate ways of enhancing the mineral industry&apos;s technology base. More emphasis is being placed on collaboration between the government, academia, and industry to formulate the innovative revolutions needed to maintain our technology edge. Through these partnerships, real issues and problems can be identified, the industry&apos;s needs as customers can be defined, and research and development activities can be tailored to meet these needs. Now is an especially exciting time in research because some special opportunities exist to encourage private industry to capitalize on Federal laboratory research and development. These opportunities arc called CRADA&apos;s. What Is A CRADA? The Congress recently enacted a mechanism that enhances collaboration between industry and government through the Technology Transfer Act of 1986. A key lea lure of this Act is a provision through which Cooperative Research and Development Agreements or CRADA&apos;s can be developed to encourage industry and government to work together and stretch their research budgets. By entering into a CRADA, a private, non-Federal company can cost-effectively perform research by sharing the costs of this research with the Federal Government. The agree¬ment involves no transfer of funds from the Government. The Government agrees to provide personnel, services, facilities, equipment or other resources (but nut funds) and the non-Federal party agrees to provide funds, personnel, services, facilities, equipment, or other resources needed to conduct a specific research or development effort.

Jan 1, 1992

To restore ventilation and prevent the accumulation of explosive or toxic gases by quickly installing substitutes for stoppings blown down by an explosion. Approach Temporarily replace blown down stoppings with a parachute-shaped brattice which can be erected in minutes. How It Works The self-sealing brattice is secured to the roof, ribs and floor by anchoring its nylon edge strip at several points using extensible poles, shads, or available projections such as roof bolts. The air pressure in the entry pops open the chute of lightweight sailcloth, forcing it tightly against floor, roof and rib. See Figure 1. This emergency brattice has been tested at two locations in the Bureau&apos;s Experimental Mine at Bruceton, Pennsylvania. In a test last December, one MESA inspector wearing full rescue apparel (including self contained breathing apparatus) installed a self sealing brattice in an entry at the Bruceton Mine. Although he did not have any previous experience with the device, he easily erected it in slightly less than 10 minutes, using two extensible supports (pogo sticks). Research to improve and refine the self-sealing brattice is continuing.

Jan 1, 1977