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By J. F. Barkley

During the present war emergency, under the urge of the Federal Government to store coal, the following questions are frequently asked by coal users: (a) Will the coal lose any, of its heating value in storage? (b) Will it slack and give a smaller-size coal? (c) Will its burning characteristics change in any way? (d) Will it catch fire from spontaneous combustion? (e) What precautions should be taken when coal is stored? DISCUSSION (a) Loss of Heating Value Studies by the Bureau of Mines show that the loss of heating value of coal in storage commonly has been overestimated. Various types of storage tests were made on New River, Pocahontas, Pittsburgh gas, and Sheridan (Wyo.) coals. The following is quoted from Bureau of Mines Bulletin 136, Deterioration in the Heating Value of Coal During Storage, by H. C. Porter and F. K. Ovitz (p. 8):

Jan 1, 1943

Prevent collisions between large mine-haulage trucks and smaller vehicles parked in areas not visible to the haulage-truck operator, Approach Two electronic systems were developed to detect the presence of vehicles in the blind areas of a parked haulage truck. The systems can warn haulage truck operators of presence of vehicles that are blocked from view. The systems do not apply for trucks in travel. How It Works The systems use electronic transmitting techniques-one system is based on low-frequency radio waves and the other on very-high-frequency radio waves. Each system requires that a signal transmitter be mounted on the smaller vehicle to be detected. Continuous signals from this transmitter are sensed by receiving antennas mounted on the right front and rear of the large haulage truck. Upon receiving a signal, the receiver energizes warning lights and a buzzer in the cab of the haulage truck, alerting the operator to a possible collision hazard. Detection distance is adjustable, depending upon the size of the haulage truck, but a minimum of 30 feet was the design goal.

Jan 1, 1990

Provide an accurate, reliable means for determining when a sealed mine or mine section can be safely reopened after a fire. Approach The Bureau of Mines performed a research investigation that resulted in the development of a mathematical formula for deriving a quantity, called RATIO, which can be used to define when a sealed mine or mine section has returned to safe recovery conditions after a fire. Research Results There were two major results from this Bureau research. Over a period of several years, the Bureau of Mines conducted six experiments at its Bruceton Experimental Mine in Pennsylvania. The experiments involved sealing the mine after several tons of piled coal had been allowed to burn continuously for 2 to 3 days. Although gas data obtained during the experiments revealed nothing significant, measured smoke particle levels were found to correlate with the stages of combustion and temperatures of the smoldering coal pile. Moreover, it was found that no smoke particles are produced when high-temperature smoldering exists deep within the mass of the coal pile since the smoke particles are filtered by the coal surrounding the hot region. Smoke is emitted into the mine atmosphere only if combustion is occurring near exposed surfaces. As suggested by these findings, any decision to recover a sealed mine area based primarily upon the absence of smoke particles is not a wise derision.

Jan 1, 1988

By R. H. Kudlich

In order to assist the various Federal and State agencies using large quantities of coal to select coal best suited technically and economically to their use, the United States Bureau of Mines has placed at their disposal a fuel inspection service. As part of this service, inspections are made at the mines which propose to furnish coal to these agencies on contracts. Such inspections cover both the mine itself to ascertain its capacity to fur- nish the desired tonnage and quality of the coal, the preparation of the coal in the tipple, and the obtaining of samples for analysis to determine the quality of coal as shipped. To insure that the sample sent to the laboratory for analysis is representative of the average quality of the coal, increments are taken at intervals until a gross sample of about 1,000 pounds of coal has been collected from each of the sizes of coal shipped by the mine, while coal has been coming from all parts of the mine. In reducing this gross sample to the small sample which is sent to the laboratory for analysis it is necessary to crush and quarter the coal by a certain standardized method until only 5 or 6 pounds of coal small enough to pass through a 3/16-inch square-mesh screen remains. The ordinary method which the bureau has followed was to crush the coal by hand with a tamper, such as is used for tamping concrete, on some hare smooth surface and to reduce the volume by quartering and riffling. During the past few years the demands from various Federal and State agencies for this service have been increasing rapidly in respect to bituminous coals. In addition to this, which might be called the normal increase, numerous requests have been received for similar service in respect to anthracite. It was obvious that if this increased demand was to be met it would be necessary either to increase the force allotted to this work or to provide the present force with some means by which their work could be made more effective. A care- ful survey of the situation showed that the greatest amount of time was consumed in trans- porting the men and their equipment from mine to mine in the same district, and in reducing the gross sample to the small finely crushed sample which is to be sent to the laboratory. Both of these phases of the work could be greatly accelerated by providing a motor truck of suitable speed and capacity, carrying a power-operated crusher, and the proper auxiliary equipment to store the gross sample as collected and to reduce it in volume efficiently after it has been crushed. Such a truck has been provided and placed in service. In the eight months it has been in operation the desired results have been fully attained. About twice as many samples as usual have been taken during that time by the same 2-pan crew assigned to this work. Many of the mines in the eastern part of the United States are in hilly or mountainous regions and can be reached only over rough, practically unimproved roads. Hence the speci- fications for the truck were drawn to cover high-quality, long-life trucks, in order that

Nov 1, 1931

By Helen E. Edwards

The Bureau of Mines is engaged in a systematic evaluation of the thermodynamic properties of combustion gases. These studies are designed to provide basic thermodynamic information of high accuracy facilitating the theoretical study of flame and combustion phenomena. This report is the third of a series3/ presenting results of the study for particular fuel-oxidant systems. The equilibrium composition of the products of combustion and the adiabatic flame temperatures of specified oxyacetylene systems have been computed.

Jan 1, 1953

By T. M. Garland

This report presents a Bureau of Mines assessment of crude oil and associated gas production and reserves that would result from different drilling efforts in the lower or contiguous 48 States during the 1972-85 period. The drilling effort was based upon five growth rate assumptions from the 1971 level. Additions to crude oil reserves were computed for nine cases resulting from the use of three equations for findings per foot drilled and three constant revision factors. The results indicate that the United States will not become self-sufficient in crude oil production by 1985 and also illustrate the lead time required to reverse the decline in oil production. Discussion is limited to three of the nine cases to provide high, intermediate, and low results. More emphasis is on the intermediate case because it is indicative of the most probable trends. The methodology and statistical data are included in the appendices.

Jan 1, 1974

By John Durkin, Harry Dobroski

This paper presents a general overview of the Bureau of Mines' programs in the areas of operational and post-disaster communications. These programs encompass both hardware developments and system evaluations. Topics discussed include a new visual paging system compatible with existing pager phone lines, a means of modifying commercially avail able pager phones to permit selective paging and message leaving, a multiplexed telephone system that uses twisted shielded pair and requires no central control, medium frequency hardware developments, and a manual for mine communications. Research has continued in the area of post-disaster location and communications. This research is based on seismic and electro- magnetic techniques. Each has been extensively studied and field tested to better understand its ability to perform effectively. A brief description is given of the post-disaster program. Results are promising and provide insight into future areas of research.

"It is evident that the incidence of coal worker's pneumoconiosis (CWP) or black lung disease varies in different coal producing regions of the United States. Many people have hypothesized about the reasons for the differing occurrences. Because underground coal mining involves many mining methods under changing geological conditions, several factors may be involved in contracting CWP such as: the amount of quartz in the respirable dust, the trace elements in the respirable dust, the rank of the coal that produced the respirable dust (bituminous, anthracite), the amount and size of respirable dust, etc.Recognizing the uniqueness of underground coal mining and CWP, research investigations involving seam characteristics, mining system and worker position are being conducted in the center to establish standard procedures for characterizing some coal properties that may be involved in workers contracting CWP. This has been accomplished by the in-mine sampling of airborne dust at various worker locations and mining system configuration and by performing laboratory analyses of mined material (coal and rock) taken from the mines. (FIGURE 49 and 50)The investigations includes a method of classifying coal seams according to their potential to generate respirable dust. It includes statistical analyses of the size and locational variations of the elemental compositions of respirable coal mine dust in operating underground mines from seams located in the eastern, midwestern, and western United States, and is currently completing research which is investigating the relationship between the elemental compositions of respirable dust sampled near a continuous-mining machine and a laboratory-produced respirable dust."

Nov 1, 1988

Monitoring systems can have numerous uses in the mine. They can aid in the efficient management of the mine by providing environmental trend data, production and maintenance control, and communications. In some cases, they can provide justification to petition the Mine Safety and Health Administration (MSHA) fog a variance of one of the mandatory safety standards. They may also increase the gross revenues of the mine by increasing the amount of coal produced or increase profits by reducing the cost of producing that coal. No single system will satisfy the requirement of all mines. Some may require simple hard-wired status-reporting systems; others, multipurpose computer-based systems that collect, analyze, and store data and perhaps control some mine functions. Even though systems vary in complexity, they are all composed of three functional components. The first component is sensors that measure the environmental or production parameters and produce an electrical signal that is fed into the telemetry. The second is telemetry devices that receive the signal from the sensors and transmit it in either analog or digital format to the third com¬ponent, analysis and display equipment. This equipment receives the transmitted signal and either stores it for later analysis or displays it. The analysis-display equipment ranges from simple strip chart recorders with preset alarms to computers, cathode-ray tubes (CRT's), and line printers that can also provide production reports. 4.2 Uses of a Mine Monitoring System A list of potential uses for mine monitoring systems, including both production-related functions and those related to health and safety, was used to develop a questionnaire. It was presented to representatives of the mining community to determine their current monitoring priorities. The responses indicated that the industry's priorities fall into the following two categories: First priority- Production and haulage Maintenance Second priority- Ventilation Communication Fire monitoring Personnel The survey shows that production-oriented systems were the most appealing to the questionnaire respondents. Since even small improvements in production efficiency and maintenance can have a large financial impact, the desirability of monitoring systems that focus on these areas is understandable. The results are summarized in table 4-1. The function that scored 100 was viewed as the most beneficial monitoring function.

Jan 1, 1984

By David Hoadley, Kenneth R. Maser, Ashok B. Boghani, James E. Billar, D. Randolph Berry, Mackenzie Burnett, Robert H. Trent

SUMMARY AND CONCLUSIONS This report describes a study to develop a detailed set of guide¬lines and equipment recommendations to be used as a guide for mine operators, mine inspectors, and equipment manufacturers in implementing the emergency escapeway standards for metal and nonmetal underground mines. It was sponsored by the United States Bureau of Mines. The first part of this report reviews the historical background of metal and nonmetal mine fires and the development of present and proposed mandatory standards. This is followed by a discussion of the survey of representative mines and how the proposed standard effects these mines. The remainder of the report covers technical discussions of each escapeway component including a comprehensive computer sim¬ulation of mine evacuation. Following the technical discussion of each group of escapeway components is a list of the pertinent guidelines. A study of past mine fires indicates that a serious commitment by operators to the proposed escape standards would be instrumental in saving lives in the future. The most significant event in a recent mine fire, in which no deaths resulted, was the very early discovery of the fire. The evacuation was orderly thanks to careful preparation by the mine personnel. However, the mine was possibly only spared a real disaster because of the discovery of the fire almost at its inception. Installation of automatic fire and smoke warning devices may be the single most important step in preventing future disasters. The self-rescuer has saved many lives in mine fires. Men have also died while attempting to use them. The reason men died was either because the unit was not working or the miner did not understand how or when to use it. There is no good excuse for either of these conditions occurring. Regular maintenance and inspection should prevent unit failures. Frequent instruction on when and how to use the self¬rescuer would prevent confusion and potential fatalities. A means of

Jan 1, 1976

By F. Cherpereel, R. Gabillard, J. P. Dubus

We present an electromagnetic method taken from the well known radiogoniometer that allows us to locate at the surface of the ground the vertical axis of a magnetic antenna transmitter buried at a depth h in the earth. The method and the equipment achieved are called R. E. P. E. (Relevé Electromagnétique de Points Enterrés). They are daily used to accurately survey old quarries by using triangulation instruments at the surface of the earth rather than in galeries where the setting difficulties considerably reduce their accuracy and increase the work length. The results of several surveys allow us to give the optimum working conditions of the instruments and show that, when the transmitter is at a 20 meters depth, its position is known at the surface with an error lower than 1 centimeter. The power transmitter is of about 8 watts and we can find its location with an error smaller than 1 meter when buried at a depth of about 100 meters. This equipment may be successfully used for location of subsurface miners. The space surrounding the transmitter must then be free from ferromagnetic bodies.

Jan 1, 1973

By Tell Ertl, Ernest E. Burgh, John R. Wagner

The principal goal of the Oil-Shale Mining Division is to develop the most economical methods and practices for mining oil shale. Experimental work in the mine has not progressed far enough to conduct full-scale breaking tests; therefore, mining season - to October 31, 1945, has been confined largely to problems connected with drilling cost oil shale. Calculations have indicated that commercial production will result in breaking the oil shale; the largest individual turn will be for drilling. This paper is a report on the progress of phase two of drilling research to date; it outlines the development of a successful hard-surfaced rock bit for drilling oil shale.

Dec 1, 1948

By G. D. Coe

Float-and-sink tests indicate what results are obtainable by gravity separation and rare therefore an invaluable adjunct to most coal-cleaning processes. However, it is difficult to make a direct interpretation of float-and-sink data on coal, and several systems for interpreting them have been proposed. Of these, that developed and used extensively by Bird3/, Yancey4/, and Gandrud5/ is considered by the author to be the most satisfactory. It makes use of four interrelated curves (hereafter referred to as be "washability curves"). These curves were explained by Bird in a paper6/ published in 1923, but his explanation has been regarded by some as not sufficiently

Jan 1, 1938

By Robert C. Dyni

The use of techniques and equipment designed to pneumatically place backfill into an underground mine opening through boreholes for subsidence abatement has historically met with limited success, largely due to the inability to directly monitor the placement of the backfill in the opening. The success of a backfilling project cannot be guaranteed if it is not known whether the underground opening has been completely filled with backfill material. To overcome the inability to directly monitor backfill placement, the U.S. Bureau of Mines developed a pneumatic backfilling system that allows for direct viewing of the backfill as it is placed in an underground mine opening. This system utilizes a recently developed pneumatic nozzle coupled with an instrumentation package that allows for real-time observations and measurements of backfill placed in an underground opening through a borehole. The nozzle utilizes a high-velocity airstream to redirect backfill falling through a pipe in the borehole and directly in front of the nozzle; the airstream redirects and propels the backfill horizontally into the .mine opening at over 100 ft/s. The instrumentation package, mounted directly to the nozzle, contains a video camera, high-intensity lamps, laser-rangefinder, electronic compass, and water sensor.

Jan 1, 2010

By Erle C. Donaldson

The pendant drop interfacial tensiometer is being used to study interfacial phenomena that influence the production of crude oil. A description of the instrument showing the modification of the cell and cell holder is presented. The modified cell and cell holder allow formation of a precise and reproducible drop size, and the image of the drop is easily alined and focused. Interfacial tension measurements and observations of film formation can be conducted at various temperatures with the jacketed cell.

Jan 1, 1967

By Sivalingam Jeevan, R. L. McConnell

Ground check monitors may be made in several configurations. Each type has unique characteristics and provides different safety attributes when applied to different mine situations. In this paper, the monitor types are discussed in relation to the mine situations. It is shown that the selection of the monitor type can have a significant effect on the safety of the resistance grounded power system. The options are discussed, and the conclusion is drawn that only one monitor configuration can provide maximum safety. Unfortunately no monitors of this configuration are presently available. In addition, when the monitor capabilities and ground wire configurations are considered as a system, it can be shown that certain configurations will lead to maximum safety. This work was supported by U.S. Bureau of Mines grant G0144138.

Jan 1, 1979

By E. P. Youngman

The Ottoman law, which was in force in Palestine before the British con- quest of the country (1917-18), still forms the basis of the legal system. Nevertheless, with respect to mining, legislation has been considerably re- vised since the British occupation and mandate, some of the Ottoman laws having been either radically altered or wholly abolished, in order that the legal status of Palestine might be more in harmony with that of western States. Legal transition is still far from being complete; however, no further mining legislation is pending at the present time (March, 1931). Revisions during the British military occupation (1917-20) took the form of proclamations of the commander in chief. After the establishment of the civil administration (1920) changes in the legal system were a decided de- parture from the Turkish laws. In 1922 the practice was begun of giving con- secutive numbers and short titles to the ordinances. The basic mining law is the mining ordinance of 1925, No. 19 (amended by mining ordinance No. 10 of 1926), an "ordinance to make provision regarding the winning of minerals, and the conditions under which minerals may be gotten, and to replace the existing Ottoman laws relating thereto." The chief regu- latory provisions are embodied in regulations (A) and (B)--mining ordinance, 1925. This mining legislation of 1925 repealed the following laws:

Nov 1, 1931

By David P. Lindroth

The Bureau of Mines has developed and successfully tested a hangup clearance module for use in clearing hangups in underground mine chutes and ore passes. The Bureau's tests showed that the hangup clearance module can be effectively used to clear mine hangups. Furthermore, it is believed that clearance using this module is quicker, safer, and more efficient than the method currently used. The hangup clearance module uses a ballistic disk explosive charge that can clear hangups located as far as 50 feet (15.2 m) from the position where the charge is detonated. Mine personnel can therefore set up the module and the charge it contains without being exposed to dangerous areas. This report describes the principles of operation of the module, provides data and drawings for its construction, and gives instructions for its setup and use. The report also summarizes the development of the module, briefly discusses preliminary and underground tests, and lists the current and potential applications of the hangup clearance module to underground mining.

Jan 1, 1982

By Howard C. Turnage, Dana T. Updyke

An evaluation was made of one of several improved underground communication systems sponsored by the U.S. Bureau of Mines. The system evaluated was installed in a typical metal/non-metal room and pillar mine and utilized UHF repeaters connected to a unique distributed antenna and passive reflector system which provided mine-wide communications. A microprocessor controlled data collection system was assembled and installed for the evaluation. Data consisting principally of times and durations of messages and identities of the originating transceivers was collected between February and August of 1982 (6 mos.). Analysis of the data shows that the principal benefits are reduction in time required for unscheduled maintenance and repair, enhancement of safety, and better coordination of production activities. A cost benefit analysis shows a net benefit over cost, although it is also concluded that the capacity of the system is greater than can be justified by current activity in the mine.

Jan 2, 1983

"Health standards in the U.S. are among the highest in the world. Achieving these standards have often had an impact on productivity, slowing output, and raising prices to levels that make it difficult to compete with many foreign industries. The answer to many of these problems lies in the development of new and advanced control techniques. This overview has identified some of the major respirable dust technological hurdles that have been overcome, and provided some insight into current and future approaches underway to remove these obstacles and to provide the United States with the most advanced state-of-the-art mining industry in the world from a respirable dust standpoint. The necessary developmental research is costly and time-consuming. The long-term, high-risk aspects of this effort are being addressed by the Bureau and the Generic Center on Respirable Dust, with support by industry. This should be recognized as one of the principal agents through which the great mineral potential of this Nation can be realized, and our international status as a mining power be assured without compromising the health and welfare of those who ensure it.The problem of more stringent dust standards will continue to grow. To date, approximately 40 pct of the coal mining industry has been placed on more stringent dust standards due to quartz. Control techniques must be improved if mandated levels are to be met. As longwall production increases, dust levels will also increase. In light of the industry trend toward longwall mining, if no new control technology is available, the Federal dust standard will act as a constraint on future output per hour. The Bureau has recently completed a survey of 18 coal preparation plants; 50 pct of these operate at dust levels which exceed 2.0 mg/m3; future work will be directed toward solutions in this area. The 2.0 mg standard for respirable dust is for dust particles which are below 10 pm in diameter. Recent studies have shown that dust in the range between 10 and 25 pm can cause obstructive airway disease. The Bureau is currently determining the extent of exposure to dust in this size range from various mining operations."

Nov 1, 1988