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By Jeffrey B. Osmint

The Bureau of Mines Information and Analysis Directorate collects worldwide data on virtually every commercially important nonfuel mineral commodity. These data form the base for tracking and assessing the health of the minerals sector of the U.S. economy. The Bureau's data collection activity was instituted by the 47th Congress in an appropriations act of August 7, 1882 (22 Stat. 329), which placed the collection of mineral statistics on an annual basis. The most recent authority fur the Bureau of Mines survey activity is the National Materials and Minerals Policy, Research and Development Act of 1980 (Public Law 96479, 96th Congress), which strengthens protection fur proprietary data provided to the U.S. Department of the Interior by persons or firms engaged in any phase of mineral or mineral-material production or consumption.

Jan 1, 1991

By J. P. Conway

The yielding-rock-bolt concept, as developed in South Africa, consists of a smooth-bore die or collar fitted to a standard rock bolt. Laboratory testing at the Bureau of Mines Spokane Mining Research Center under slow and fast strain rates showed that extrusion loads can be controlled by varying the configuration of the die bore and that theoretical analysis (using basically Sachs' theory of wire drawing) predicts extrusion loads of the different die-bore configurations. A derived equation, based on this research, can be used for designed die-thread combinations for any desired extrusion load. Dynamic loading resulted in slightly higher loads (15 percent) than static loading. The strain hardening effect, which increases yield and ultimate strength, was partly offset by adiabatic heating of the threads, which decreases strength.

Jan 1, 1975

By Oliver Bowles

[In an endeavor to promote greater efficiency in the lime industry, the United States Bureau of Mines is preparing a series of preliminary reports dealing with particular problems of the industry. Through the circulation of these reports, it is hoped that sufficient interest may develop among lime-plant operators to prompt them to discuss with the bureau their our experiences with these problems. By such an interchange of ideas, it is believed that conclusion may be reached which will be of practical benefit to try entire industry. The first report, "Stripping problems it Limestone quarries of the Shenondoah Valley", Serial No. 2401, was issued during October, 1922. This report t is the second of the series. It is hoped that may operators will contribute additions to the information now at hand.]

Jan 1, 1922

PURPOSE: Evaluate practical technological advances in level-dependent hearing protectors and inexpensive personal acoustic monitors. RESEARCH SUMMARY: The results of previous NIOSH research show that miners develop hearing loss much more quickly than nonoccupationally noise-exposed individuals and that miners experience a greater severity of hearing loss than would be expected for nonoccupational noise-exposed persons of the same age and gender. Using hearing thresholds at 4,000 Hz as an indicator, coal miners experience hearing loss 2.5 to 3 times greater than would be expected for persons not exposed to occupational noise. At age 50, 90% of coal miners and 49% of metal/nonmetal miners were found to have a hearing impairment. In comparison, only 9% of a nonoccupationally exposed control group had a hearing impairment at age 50.

Jan 1, 2000

By H. Reginald Hardy

This report is Volume I of a three volume final report on the micro-seismic monitoring of a longwall coal mine. Volume I deals for the most part with the detailed aspects of the microseismic field study itself, however, brief references are made to other secondary studies described in Volumes II and III. During this field study a mobile microseismic monitoring facility and associated transducers were employed to detect and record microseismic activity above a longwall panel at Greenwich Colleries, Barnesboro, Pennsylvania. The fundamental objectives of this study were (1) to evaluate the feasibility of detecting microseismic activity originating from longwall mining operations using an approximately planar, near-surface, geophone array installed above the longwall and (2) to attempt to locate the sources of the various microseismic events. This investigation has proven that, using the techniques developed it is possible to detect microseismic events at depths of more than 400 ft and at horizontal distances in excess of 800 ft from the source. The majority of the observed events were found to have frequencies on the order of 10 to 100 Hz, and particle velocities of 50 to 300 µips. When a suitable velocity model was utilized, most of the events located were computed to be within ±100 ft vertically of the coal seam and ±50 ft horizontally of the longwall face. The results of the overall research project suggest that additional research should be undertaken in a number of associated areas.

Jan 1, 1978

By David A. Monaghan, Kenneth R. Maser, Adi R. Gurdar, D. Randolph Berry

APPENDIX A - PNEUMATIC TRANSPORT OF FLY ASH 1. Introduction Two types of pneumatic transport of fly ash are critical to the success of (1) Transport of fly ash from the fly ash truck to the entrance to the borehole. Depending on the surface topography, this may be horizontal, decential and ascential. (2) Vertical downflow of fly ash through the borehole. All fly ash trucks have limited pressure with which they can pump the fly ash. Thus, the pressure drop in the fly ash hose will define the maximum length for pumping and consequently the maximum distance that the fly ash truck can be parked from the auxiliary blower. The same relationships describe the flow of the dilute fly ash-air mixture produced by mixing with the auxiliary air from the blower and thus define the selection of the pipe diameter. These are im¬portant considerations in the proper selection of the location of the passages to be sealed and the type of surface preparation required. The flow characteristics of fly ash down the borehole determine the selection of the minimum borehole diameter and the blower pressure. This appendix presents theoretical analyses of these flow regimes and summarizes the limited experimental data obtained during the field tests at Grant Town, described in Section 8.4. The analysis for the borehole flow is presented first as it is of greater interest to the program. This is followed by a discussion of the horizontal flow.

Jan 1, 1973

By Robert N. Roby

"The Moffet-Johnston property was investigated by the Bureau of Mines with the object of determining the presence of ore reserves that might be utilized during the war emergency. Preliminary examination was made during May and Juno 1943, as a result of which the Johnston 'tunnel was cleaned out and repaired, the .mime was surveyed, and a small program of exploration was undertaken. This report describes the work performed and presents the data obtained.In its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts prelimi¬nary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples and performs benefication tests. Both these branches are under the supervision of Dr. R. S. Dean, assistant director.The chemical and spectrographic analyses were made at Reno, Nov., under the direction of A. C. Rico, acting engineer in charge, Rare and Precious Metals Experiment Station, Bureau of Mines. The ore-dressing tests were under the direction of Rollien R. Wells, metallurgist, at the Salt Lake City laboratories of the Bureau of Mines.The author acknowledges the cooperation and assistance of the lessee of the property, H.R. Hakes, who furnished nine reports and other information.The Moffet-Johnston property is in secs. 2 and 3, T. 3 S., R. 5 W., in the Tidal Wave mining district of Madison County, Montana.The portal of the Johnston adit is near the mouth of Bear Gulch, 9 miles northeast of Twin Bridges, Mont. It is reached by an improved dirt road that serves mining properties farther up Bear Gulch. The Moffet mine and the Mountain View shaft are now accessible from the Bear Gulch road over an access road recently completed by the U. S. Grazing Service. The Grazing Service road has also been supplemented by bulldozer trails built by the Bureau of Mines.An electric-power line extends from the Montana Power Co's substation at Twin Bridges to mines at the head of Bear Gulch and passes within 200 feet of the Johnston portal.The claims of the Moffet-Johnston property were located about 1900. A report by H. V. Winchel, consulting geologist, in 1904 indicates that most of the development on the Johnston adit was completed by that date. At the time of the Winchel report, the Moffet workings had just penetrated the first ore shoot (fig. 4)."

Sep 1, 1946

By Manuel Gomez

A computerized moving average technique was developed to interpolate coal seam characteristics between sample points. The interpolative method coupled with multivariate regression analysis and simulation procedures was used to forecast coal properties not readily obtained from an analysis of drill core samples. Coal property forecasts were of two kinds: (1) specific mine property forecasts that are suitable for mine product control and yield a good approximation of the local variation along both the vertical and horizontal axes of the seam, and (2) regional estimates where much of the local seam variation is smoothed out, but the general trends are maintained. Forecasts of the volatile matter, ash, total sulfur, and the heating value for part of the Pittsburgh seam located in Ohio, Pennsylvania, and West Virginia were in good agreement with independent evaluation data. Spatial configuration for preparation characteristics, particularly, the effect of crushing on sulfur release, low-and high-temperature carbonization properties, the Hardgrove grindability index, the coal hardness index, gasification variables, and hydrogenation factors were constructed for the same area of the Pittsburgh seam. These forecasts may be developed from drill core data collected in the exploration phase of mining. The results, which may take the form of a series of maps, are useful to mining, chemical, and combustion engineers, to economists and mine managers, as well as to coal users for mine design, economic analyses, energy forecasts, utilization studies, mine product control, and environmental control and programming.

Jan 1, 1974

By Dennis R. Dolinar, Christopher Mark, Gregory M. Molinda

Despite more than half a century of experience with roof bolting, no design method has received wide acceptance. To begin to improve this situation, National Institute for Occupational Safety and Health (NIOSH) conducted a statistical study of roof bolt performance at a number of mines throughout the U.S. Case histories were collected from 37 mines with a variety of roof bolt types and patterns in a wide range of geologic environments. Performance was measured in terms of the number of roof falls that occurred per10,000 ft of drivage. The study found that roof falls are rare when the roof is strong and the stress is low, even with light roof bolting patterns. The focus of this paper is on the more difficult conditions, where the roof is weaker and/or the stress is higher. Analysis of the results led to guidelines that can be used to make preliminary estimates of the required bolt length, capacity, and pattern. The guidelines are based on the depth of cover (which correlates with stress) and the roof quality (measured by the Coal Mine Roof Rating (CMRR), and the intersection span. Another contribution is a formula for estimating the horizontal stress level in the eastern U.S. coalfields as a function of the depth of cover. The design guidelines are currently being implemented into a computer program called Analysis of Roof Bolt Systems (ARBS).

By John Hays Hammond, James Douglas, J. PARKE CHAN- NING, W. R. Ingalls, J. R. Finlay

The committee making this report, consisting of Walter Renton Ingalls (chairman), J. Parke Channing, James Douglas, James R. Finlay, and John Hays Hammond, was originally appointed at a meeting of the American Mining Congress at Denver, Colo., in No- vember, 1906. The object of this appointment was the drafting of a modern law governing quarrying and metalliferous mining which could be recommended to the several States for adoption, in the hope that the passage of such a uniform law by the mining States would tend to lower the number of fatal and serious accidents. The first step of the committee (the personnel of which has re- mained unchanged from the beginning) was to procure copies of existing laws from the officials of the several States of the Union. With the assistance of the Engineering and Mining Journal, copies of the laws of Great Britain, the Transvaal, New South Wales, Victoria, Queensland, Western Australia, Tasmania, New Zealand, and certain European countries were also obtained. The replies to the inquiries made at that time developed the fact that a number of States in which mining was carried on had no laws at all. Other States were found to have elaborate provisions regulating coal min- ing, but none applying to metalliferous mining. Still other States were found to have miscellaneous and unrelated provisions passed at odd times, seemingly as the result of the occurrence of some dis- aster or other.

Jan 1, 1915

By A. S. Griffiths, J. E. Evans

Noise processing experiments with ELF (3 to 300 Hz) atmospheric noise and signals in the 40 to 80 Hz range are described. The primary purpose of the experiments was to record and analyze wideband ELF noise in order to design the noise processing portion of a receiver which minimizes the required transmitter power. The application of appropriate theory and extensive simulations led to a noise processor which consists of the following functions: (1) a compensating (or whitening) filter, (2) a prenotch filter clipper, (3) notch filters at frequencies of manmade interference (e. g., power lines), (4) a post-notch filter clipper, and (5) a phase-coherent linear matched filter. The nonlinear processing provides considerable gain relative to a linear receiver (i. e. , a receiver consisting only of a matched filter and appropriate whitening filters). It is convenient to measure sys tem performance in terms of an "effective noise level" which is equal to twice the received signal energy divided by the signal to noise ratio at the matched filter output. For example, the highest effective noise levels observed at 45 Hz with the nonlinear processor were about -134, -131 and -137 dB wrt 1 amp/m [Hz] using Saipan, Malta and Norway data, respectively, compared to 1 percent exceedance levels of effective noise for the linear receiver of about -115, 115 and -130 dB wrt 1 amp/m [Hz] respectively.

Jan 1, 1973

By Lloyd A. Morley, Robert Stefanko

The most time-consuming research segment was assembling the ref¬erences. These are provided immediately after the conclusions but are divided into two categories. The first is directly applicable publi¬cations, correspondence and personnel communications. The second listing contains those publications that are not directly tied to the research but where a probable application exists. In both listings, all important USBM publications are provided. The reference numbers used in the report apply only to the first reference portion. Further¬more, it should be noted that all entries are not used but are retained to help anyone who wishes to look further into different or allied areas of this research topic. Explosion-proof enclosures have been researched since approxi¬mately 1906. Even so, little is understood about the mechanism by which they are effective. Due to the voluminous literature published, there is a good probability that the assembled list is still incomplete. The literature search took the following directions. Work was first directed to reviewing the several references assembled by the Department of Mineral Engineering - Mining Section prior to the present project year. As a result, some duplications and inapplicabilities were found and eliminated. The primary sources of the previous search were the commonly available and usually superb library listings, such as Engineering Abstracts. Because these sources have enormous content on all subjects, they were cross-checked in the first semiannual period several times by different individuals to make sure all normally avail¬able literature were uncovered.

Jan 1, 1974

By Lloyd A. Morley, Robert Stefanko

This report has presented a literature review of explosion proof¬ing of coal mine electrical equipment. The international "state-of¬the-art" is an extremely difficult definition to quantify but, from the preceding paragraphs, it is evident the international community be¬lieves that it is represented by the International Electrotechnical Commission's Publications. Five questions were set forth during the beginning of this report. Each will be evaluated in light of the preceding discussion. 1. Can Schedule 2G specifications on explosion-proof containers be substantiated? Literature was found in the three main problem areas, surface temperature, mechanical strength, and explosion transmission, to determine this. Surface temperature requirements are adequate except for equipment that can normally overload, and the required intern¬al pressure does afford some margin of safety. However, in terms of safety, gap dimensions are about ten times smaller than that needed. 2. Is it possible to replace the Schedule's design requirements with performance specifications? Two primary areas were determined as mechanical strength and explosion transmission. As was mentioned, for present flange and gap standards, the 150 psig requirement is adequate. Furthermore, it is the authors' opinion that the level cannot be re¬duced if the present gap requirements are retained. The Schedule now requires that 16 tests be run, but the literature suggests that only from three to six examinations are necessary. Then by using the abso¬lute maximum pressure from these measurements or 150 psig, whichever is

Jan 1, 1974

By Bruce K. Cantrell, Stephen W. Stein, David Hassel, Harvey Patashnick

The Mine Safety and Health Administration. Department of Labor, requires coal mine operators to measure compliance with federal re¬spirable dust exposure standards periodically using approved gravi¬metric samplers. However, the gravimetric approach, with its inher¬ent delays, cannot provide dust concentration data quickly enough to allow on-site correction of inadequate dust control strategies or re¬moval of personnel from harmful environments. Furthermore, alleged tampering with dust samples collected to determine compliance with standards prompted the Secretary of Labor to appoint a special Respirable Dust Task Group to study options to improve monitoring and control of respirable coal mine dust. The Mine Safety and Health Administration's Task Group recommended that the U.S. Bureau of Mines develop a fixed-site monitor that would provide continuous information to the mine worker and mine operator regarding dust levels and the status of compliance with the applicable respirable dust standard. In response to the Mine Safety and Health Administration's request, the U.S. Bureau of Mines is investigating several sensor tech¬nologies for continuously monitoring respirable coal mine dust. One of these technologies is the Rupprecht and Patashnick Co. tapered element, oscillating microbalance. The bureau is in the process of investigating the suitability of using this sensor in the high humidity and vibration environment of underground coal mines. Laboratory tests have indicated that, with modification, the sensor can meet the humidity and vibration requirements for underground coal mine use. Currently, the bureau is developing

By C. B. Manula, R. L. Sanford, R. A. Rivell

A generalized flow diagram is presented in Figure 1, which shows the relationship of major model functions. This chart does not necessarily represent the anatomy of the computer program, but is designed to illustrate the informational interchange between major model functions. The related flow-charts-and computer program are listed in Parts I and II, Appendix A, respectively. Mine Car Stations The mine car stations are the activity centers for the model. The locomotive logic structure is designed to provide these stations with adequate cars and to clear them of car buildup. The model is designed to simulate a three stage haulage situation which suggests the need to differentiate station levels by type numbers. These are: a) TYPE 1 stations - mine cars are loaded here; b) TYPE 2 stations - intermediate stop and storage for mine cars; c) TYPE 3 stations - all mine cars that are stored here leave mine; and d) TYPE 4 stations - mine portal. TYPES 1, 2, and 3 have all loaded cars assigned to an ascending TYPE as their next destination. In input, if single stage haulage is designated, TYPES 1 and 3 do not exist, and if two stage haulage is called for, TYPES 2 and 3 are absent. A motor is not permitted to exchange cars between stations of the same type. Station Status Update. One major model function is to continuously evaluate the status of each mine car station. The major evaluations

Jan 1, 1974

Rank the dust knockdown (airborne capture) ability of six different types of water spray nozzles, Approach A fixed quantity of dust is released into a large, closed chamber in a laboratory. Water sprays are turned on inside the chamber and their effectiveness on the dust cloud is evaluated from the rate at which the dust disappears. This method better simulates dust suppression underground than methods tried earlier. The results of the laboratory test were confirmed by conducting tests on a full-scale mod-el continuous miner face where dust levels were measured in the return airway. Results of the Closed Chamber Tests The graph indicates that atomizing nozzles provide the best use of water for dust scrubbing. However, use of these nozzles is limited by their susceptibility to damage and clogging. Hollow-cone nozzles perform almost as well as atomizing nozzles. Test results also indicate that full-cone, venturi-assisted, and flat-fan spray cones are about two-thirds as effective as hollow-cone nozzles. The least effective were venturi nozzles designed for moving air. The most significant advantage of hollow-cone nozzles over other nozzles tested is reduced clogging due to larger orifice size. The hollow-cone nozzle used in the test and depicted by the graph was type BD-3 manufactured by Spraying Systems Co., Wheaton, IL. This nozzle is already used on many continuous miners. Other hollow-cone nozzles of

Jan 1, 1982

Provide mine safety personnel, MSHA inspectors, and original-equipment manufacturers with guidelines and a check list for inspecting rollover protection structures (ROPS) being used in mining operations. The Problem ROPS are provided on mobile surface mining equipment to protect operators from such safety hazards as machine rollovers, falling objects, and collisions. However, the protective capability of a ROPS can be greatly reduced if it is damaged. Certain kinds of damage, such as hair- line cracks, corrosion, and loosened bolts, may occur as a result of normal machine use but may not be recognized as unsafe by untrained personnel. Therefore, the Bureau of Mmes designed a manual which can be used by mine personnel when inspecting ROPS equipment. The Manual The manual was prepared to help acquaint mine safety personnel and MSHA inspectors with typical ROPS deficiencies and their causes. It provides a systematic means for inspecting ROPS so that the identified deficiencies and their causes can be corrected. It is suggested that an inspection of the ROPS be conducted after every 1,000 h of equipment operation, or sooner if the structure has been subjected to any unusual loads which could cause damage, such as a rollover, highwall caving, or collision. The manual also details common deficiencies in the structure and attachment hardware which may affect the service life. The checklist, when used as instructed in the manual, provides a means for systematically inspecting the structure to ensure maximum protective capability and conformance with applicable Federal regulations.

Jan 1, 1986

By Kevin Connor

The mineral industry continued to be an almost negligible contributor to the country's economy as the Government continued its 1979 ban on any mineral exploitation for export; a policy initiated at the end of 1979. A national program had been underway since that time to map and inventory all mineral resources so as to permit future exploitation of mineral wealth in the beat interests of the country and its inhabitants. In March 1982, the British Sulphur Corp. Ltd., under contract to the Burundi Government and the International Bank for Reconstruction and Development (World Bank), began a feasibility study of Burundi's phosphate deposits at Matongo-Bandaga for potential commercial exploitation. The 1-year project effort was to define ore reserves, conceptually design mining operations and processing facilities, estimate capital and production cost, and develop a regional market and distribution survey. Work completed during the year comprised geological exploration and reconnaissance and 1,200 meters of core drilling. Reserves in excess of 5 million tons of ore-grade phosphate were estimated available for mining. Rare earth mineralization was associated with the primary apatite. The associated carbonatite within the rock matrix was preliminarily assessed to be of value as a raw material for the manufacture of cement. The contract effort was valued at $1.2 million? Matongo-Bandaga is located approximately 40 kilometers north of the capital city of Bujumbura and alongside one of the country's few paved roads.

Jan 1, 1984

By Michael D. Fenton

Detailed comprehensive assessment of the performance of Afghanistan's mineral industry during 1987 is virtually impossible, owing to the paucity of reliable published information. It was evident, however, that the level of civil disorder, now in its eighth year since the arrival of significant numbers of Soviet troops, was in actuality little removed from open civil war. Insurgents controlled substantial areas of the country and imperiled any industrial activity in many places. Assistance programs by the U.S.S.R. and other Eastern European nations were directed at developing the country's meager mineral industry, but the economy was generally viewed as chaotic. The inflation rate was somewhere between 20% and 30%; major food shortages contributed to the discontent of the population, and numerous villages were devastated by Soviet and Afghan Government campaigns to destroy the insurgents and cut their supply routes. Moreover, proposals by the Soviets and the Kabul Government aimed at reducing tensions with the rebels and scaling down the warfare seemingly were taken by the opposition as signs of weakening by the Soviet-backed Government, and rather than reducing aggressions, seemed to heighten insurrectionist activities. Efforts to entice the substantial number of Afghans who have fled to nearby areas of Pakistan and Iran to return to their country seemingly were failures, and indications near yearend that the Soviet Union might soon begin withdrawal of its occupation force of nearly 120,000 did little if any to reduce disorder.

Jan 1, 1989

Several federal and state agencies have promulgated regulations that require the installation of operator protective structures on mobile equipment used in mining, construction, agriculture and logging industries. These regulations cover many different types of vehicles, from small farm tractors to large rubber-tired front-end loaders, and require structures that help protect the operator from death or injury from vehicle overturns, from falling tree tops and logs, from falling rocks, and from tree limbs in clearing operations. Two general types of vehicle operator protective structures have evolved over the past twenty years. The first of these is the "Roll-Over Protective Structure'' or "ROPS" that is essentially a "roll bar" or "roll cage" that provides a relatively safe area for the vehicle operator if the vehicle should tip over and roll. The second protective structure is the "Falling Object Protective Structure" or "FOPS" that provides overhead protection against falling material. The terms "ROPS" and "FOPS" are often used interchangeably (sometimes inaccurately) with "cabs", “canopies” , "roll bars" , protective structures" and other such descriptive names. In this report, "ROPS" describes the function of the structure; "FOPS" also describes a particular function. Thus a ROPS/FOPS could describe a cab or a canopy that provides both roll-over protection and falling object protection. “MESA” is used as an abbreviation for the Mining Enforcement and Safety Administration; "USBM" is used to abbreviate the U, S. Bureau of Mines.