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By Russell J. Foster

This Bureau of Mines review focuses on the extent to which technologically and economically feasible programs in substitution, improved processing practices, including recycling, and design can achieve conservation of cobalt, chromium, manganese, and platinum-group metals, and thus reduce U.S. vulnerability to interruptions of supply. In addition, supply-side options--domestic and foreign resources, ocean minerals, and stockpiles--are identified. The report consolidates four major studies on these strategic and critical minerals sponsored entirely or partially by the Bureau in the last few years. These studies have been updated with further information from the recent literature.

Jan 1, 1985

Introduction The Coal Mine Roof Rating (CMRR) is a roof classification system. It was first introduced to the mining community in 1994.The CMRR filled a longstanding need to quantify geologic description of coal measure rocks into an engineering value that could be used for mine design. It has now been written to a user-friendly visual basic code that can be run on any PC with a Windows operating system. Background Rocks that form the roof of coal mines can vary widely and quickly in composition, extent, and defects. This results in an equally broad range of rock properties that can substantially affect the ability of the rock mass to form a stable mine roof. The CMRR was designed to evaluate the properties of the coal mine roof rock mass that contribute to its weakness and convert them into a relative strength rating from 0 to 100. These properties include the cohesion and frequency of discontinuities like bedding, slips, shears, and joints; uniaxial compressive strength (UCS); and moisture sensitivity. With simple lab and field tests and observation, the CMRR can be calculated by technical and operating personnel with a minimum of training. The CMRR has been widely accepted in both U.S. and international coalfields. As a result, a number of roof control applications have been found for the CMRR. It is currently used as an input component in the Analysis of Longwall Pillar Stability(ALPS) program, which is used to design longwall chain pillars. Incan be used as a criterion for determining the appropriate width of mine entries. It has also been used to indicate the appropriate length of cut in weak ground. The CMRR can be used as a strength parameter to characterize inter burden between mined seams in the numerical modeling of subsidence effects. In any area where an estimation of coal measure rock mass strength is required, the CMRR can be adapted to fill this need. How It Works Originally designed to be used with underground exposures, the CMRR can also be calculated from core. The chisel test for bedding cohesion and the ballpeen hammer test for UCS are inappropriate for core. These tests have been replaced by point load testing both axially and diametrally. Two other measures that are common to standard core logging—Rock Quality Designation (RQD) and fracture spacing—are also used to estimate rock weakness. With these easily obtained parameters, the CMRR can be calculated from core and used in the mine planning and exploration phase. The input screens allow calculation of the CMRR for both underground exposure and core. The CMRR is reported both as a “dry" value and as a groundwater-adjusted value for moisture-sensitive rocks. There is a graphical output report featuring a lithologic column with annotated unit ratings and a roof bolt symbol representing the height of the bolted horizon. Another important feature is an AutoCAD interface. This feature allows the export of located CMRR data directly to an AutoCAD layer in XYZ form. In this way, drill hole data can be inserted directly to a base map.

Apr 1, 2003

By Dennis R. Dolinar

Screen material in the form of welded wire mesh and geogrids are used in underground coal mines to prevent the fall of small pieces of rock from the roof between roof bolts. Further, if the screen is installed during the production cycle, roof fall injuries can be reduced significantly. Therefore, the National Institute for Occupational Safety and Health (NIOSH), because of the safety implications, conducted an evaluation of screen materials commonly used in U.S. coal mines to determine their support characteristics and identify the parameters that could affect their performance with respect to controlling the fall of rock from the roof surface. To evaluate the load and stiffness characteristics of the screen, a test frame was designed and installed in the Mine Roof Simulator (MRS) at the NIOSH Pittsburgh Research Laboratory (PRL). With this test set up, the screen is bolted at four corners of the frame and a center load is applied. The test set up allows for up to 20 in of screen deflection while the load and screen defection are continuously recorded. A series of tests were conducted to evaluate the effects of various parameters such as bolt tension, the type of load bearing surface and the size of bearing plates on welded screen performance. The most common screen material used in U. S. coal mines is an 8-gauge wire welded in a 4-by-4-in spacing or aperture. The peak screen load was normally limited by wire breakage. The conditions at the bearing plate influence the nature of the wire breakage. However, the screen stiffness was controlled by slippage at the bearing plates, and by weld and wire failure. The size of the bearing plate had a significant effect on the performance of the welded screen. Therefore, the design capacity of the 8-gauge screen is evaluated based on plate size. For a 6-by-6-in bearing plate the average peak load is 2,900 lb with a stiffness of 250 lb/in. For an 8-by-8-in bearing plate, the average peak load is 4,500 lb with a stiffness of 430 lb/in. These test results are based on a 4-by-4-ft bolt spacing. A geogrid mesh was also tested.

The Mine Safety and Health Administration (MSHA) defines an independent contractor as "any person, partnership, corporation, subsidiary of a corporation, firm, association or other organization that contracts to perform services or construction at a mine." Contractors that perform specific types of work are required to report the number of employees who perform work at coal mines and at noncoal mines.

Jan 1, 2004

By Joseph P. Flick, Kathleen M. Kowalski, Lynn L. Rethi, Roberta A. Calhoun

Many miners are involved in tasks at the mine site that are similar to those sub-tasks performed in general construction, maintenance and repair (CMR) type work activities. As a result, many of the injuries in the mining industry today can be traced to employees performing these CMR type work activities. Indeed, a recent analysis of a major aggregate company revealed that 65% of all injuries documented originated from performing such CMR activities. It is hypothesized that the number of injuries to miners performing construction, maintenance and repair (CMR) work activities on mine property may be reduced through improved training that focuses on better hazard recognition using the numerous visual and other cues that are available for evaluating workplace health and safety hazards. To this end, researchers at NIOSH’s Pittsburgh Research Laboratory have merged two proven methods of training miners to recognize hazards, stereoscopic (3-D) slides and the concept of degraded images, into this training program. Stereoscopic (3-D) slides have been shown in earlier NIOSH and U.S. Bureau of Mines research to be an effective training aid for improving the ability of miners to recognize various geologic and mining-induced irregularities that can cause groundfalls.3 They realistically portray the natural mine environment, and thus are an excellent training aid for teaching miners to recognize such visual cues. The degraded image concept, originally developed by the military and used for target detection training, describes scenes where the target is partially hidden by cloud cover, dust, rain, natural barriers, buildings, or other obstructions that can camouflage or confuse the target. Research had shown that flight observers who were trained with less than ideal (or degraded) pictures were more successful in subsequent identification of targets than those trained using ideal (or highlighted) pictures of targets. In order to investigate this concept for training miners to recognize hazards, NIOSH researchers developed a prototype hazard recognition training program using such mining scenes. A control program based on traditional highlighted mining scenes was also developed. Both programs were applied to subjects in a field experiment. Results indicated that miners trained with the degraded images did significantly better on a follow-up test of hazard recognition.4 This hazard recognition program teaches trainees to look for hazards in a more realistic manner than that of the control program. This specific training program for CMR activities involves using the degraded image concept and 3-D slides. The module is designed to educate workers on hazard identification techniques and safe work practices. It focuses on teaching miners techniques for recognizing visual (sight) cues, and then uses these cues to evaluate mining conditions. It should be stressed that other senses, such as sound can also play an important role in hazard detection.

Jan 1, 1999

This Technical Memorandum Report is a collection of three working memoranda, prepared during the course of our work for the Bureau of Mines and bound together for convenient reference. These working memoranda present preliminary performance estimates, for baseband voice and narrow- band through-the-earth electromagnetic communications systems of principal interest to the Bureau, for operational/emergency mine communications. The calculations were prepared to obtain early indications of the feasibility and governing parameters of such communications systems. They are based on limited, but pertinent, coal mine electromagnetic noise data acquired to-date by Bureau of Mines contractors; and of theoretical signal-attenuation characteristics for two transmitter antenna types of present interest to the Bureau. The memoranda examine the cases of baseband voice and narrowband communications for uplink and downlink transmissions, for frequencies up to 3kHz. Downlink transmissions are via a horizontal wire antenna, up- link transmissions via a vertical-axis loop antenna, for typical mine depths of 300, 600, and 1000 feet. Representative coal-mine overburden conductivities of 10-2 mhos/meter (moderate and common) and 10-1 mhos/meter (high) were used; for voice and narrowband, 10-1 for narrowband only. Examples of high, moderate, and low; surface and subsurface; harmonic and broadband-impulsive noise conditions were taken from NBS and Westinghouse (WGL) mine noise data, together with examples of high- and low levels of ELF atmospheric noise taken from M.I.T. Lincoln Laboratory data. These feasibility calculations are not intended to serve as definitive and complete treatments, but as a starting point: to establish first-order estimates of the magnitude and variability of transmitter power requirements under different noise, overburden conductivity, and mine depth conditions; to identify relationships, conditions, or frequencies that are likely to limit or enhance system performance; to reveal items requiring further investigation and data still required; and to suggest practical methods for optimizing system performance. These objectives were met by the calculations. Simple experiments to support these calculations can and should be carried out; together with more detailed investigations of specific modulation, coding, noise-suppression, voice-compression and signal-conditioning techniques, aimed at producing through-the-earth operational/emergency mine-communication systems that are not only effective, but practical and economically sound.

Jan 3, 1972

By BUREAU OF MINES

The Bureau of Mines, in its investigations of respiratory apparatus for use in mines and allied industries; tests equipment that is voluntarily submitted by manufacturers in accordance with published schedules of tests. These tests are designed to insure that the equipment has the minimum requirements for safety in use. Approval certificates are issued for apperatus that meets the bureau's specifications, and the manufacturer is permitted to mark his equiment with a seal showing that it has been approved as "Permissible." A complete list of per- missible self-contained oxygen breathing apparatus, gas masks, and hose masks tested prior to January 1, 1930, was published in Bureau of Mines Information Circular 62309. The present list includes all equipment tested and approved prior to July 1, 1930.

Sep 1, 1930

By Edward P. Barrett

[Iron oxides, when reduced at temperatures below 900° form a dark gray substance, very porous bait otherwise in almost the same form as the original particles. In the temperature ire range of 1,000 to 1,100° the product is pertly sintered but still shows the outlines of the original particles. Those products are known as "sponge iron." At temperatures of 1,100 to 1,2000 the metallic iron begins to flow together and to a semifused, pasty, porous mass called a "bloom," which can he worked under a hammer to form a product similar to wrought iron; it contains slag inclusions and is too low in carbon to make steel. If the temperature is 1,300 to 1,300°, part of the iron will fuse enough to absorb more carbon. The dissolved carbon lowers the melting point and still more carbon is absorbed. The melted portion acts a flux for the unmelted metallic particles until the entire mass becomes a high-carbon fluid known as "cast iron." Sponge iron was probably the form in which the first iron was recovered from the ores. As early as the eighth century the Catlan forge3 developed into a low-shaft furnace known as the "high bloomary," in which iron eras produced in the form of a pasty mass. In 1340 the first blast furnace was built in Belgium. The greater part of the iron was made into wrought-iron blooms by crude puddling processes. Charcoal was used as the fuel until tie latter part of the 17th century when coke was used in England. In 1865 Bessemer built his first converter in. England, and within a few years the Siemen's regenerative open-hearth furnace was developed, also in England. Enormous expansion in the metallurgy of iron followed. The idea of "direct processes" for the production of iron arid steel has persisted throughout all this time. The production of steel from sponge iron has theoretical advantages over the present-day standard methods, and handreds of so--called "direct processes" have been proposed or tried during the past century.4]

Jan 1, 1929

By R. V. Ramani, A. S. C. Owili-eger

This report was prepared by The Pennsylvania State University under USBM Contract No. G0111808. The contract was initiated under the Coal Mine Health and Safety Program. It was administered under the technical direction of DMSE, with Mr. G. R. Schottler acting as the technical project officer. Mr. J. A. Herickes was the contract administrator for the Bureau of Mines. This report is a summary of the work recently completed as part of this contract during the period June, 1971 to December, 1973. This report was submitted by the authors on March 31, 1974. Part of the research reported here was originally done on a grant from the Department of Environmental Resources, Commonwealth of Pennsylvania and reported in Special Research Report No. SR-95 (February 25, 1973) of the Coal Research Board, The Pennsylvania State University.

Jan 1, 1974

To help mine safety and health professionals manage and reduce hazardous noise exposure with a software tool that simplifies the record-keeping and analysis process. Background Hearing loss resulting from overexposure to noise continues to be a problem throughout the U.S. mining industry. Studies indicate that 70%?90% of all miners have a noise-induced hearing loss severe enough to be classified as a hearing disability by the time they reach retirement age. To address this problem, the National Institute for Occupational Safety and Health (NIOSH) developed the Determination of Sound Exposures (DOSES) software program. DOSES is designed specifically for use by mine management and safety personnel to simplify the record-keeping and analysis associated with time-motion studies, making it easier to identify and solve noise exposure problems.

Jul 1, 2009

To reduce operator exposure to drilling noise from roof bolting machines. Background Noise-induced hearing loss (NIHL) is a prevalent occupational illness in the United States. Studies indicate that 70%?90% of miners have NIHL significant enough to be classified as a hearing disability. Mine Safety and Health Administration studies indicated that roof bolting machine operators are among those overexposed to noise. Field studies support the premise that, on average, drilling is the loudest noise source to which a roof bolting machine operator is typically exposed and contributes greatly to the operator?s noise exposure. The National Institute for Occupational Safety and Health (NIOSH) has further determined that the drill steel and chuck radiate a significant amount of noise during drilling. To address this noise hazard, NIOSH developed a collapsible drill steel enclosure (CDSE) to encapsulate the drill steel during the drilling portion of the roof bolting machine duty cycle. In addition, NIOSH is collaborating with J. H. Fletcher & Co. in the continued development of a CDSE.

Sep 1, 2008

By Harry F. Weaver

Rivers in industrial and raining areas frequently are contaminated by material dumped into them causing the water to carry in suspension large amounts of silt, which subsequently is deposited alone; the banks and, ultimately on the agricultural lands if the water is used for irrigation purposes. Two common examples of this practice are the dumping of breaker refuse in the anthracite region of Pennsylvania and the dumping of tailings from the metallurgical mills in various metal-mining districts. Studies in stream pollution and its resultant problems are very important, and surveys are constantly being made by Federal and State agencies, as well as by private companies, to determine the quantity of solids actually being carried by these watercoarses. These studies require accurate sampling of the silt-carrying water to determine the amount of solids within reasonable limits. A device that will obtain reasonably accurate samples of material from silt-bearing streams is described in this circular.

Jan 1, 1943

By BUREAU OF MINES

The Bureau of Mines in its investigations of respiratory apparatus for use in mines and allied industries, tests equipment that is voluntarily submitted by manufacturers in accordance with published schedules of tests. These tests are designed to insure that the equipment has the minimum require- ments for safety in use. Approval certificates are issued for apparatus that meets the bureau's specifications, and the memfacturer is permitted to mark his equipment with a seal showing that it has been approved as "Permissible." A complete list of permissible self-contained oxygen breathing apparatus, gas masks, and hose masks tested before July 1, 1930, was published in Bureau of Mines Information Circular 6362.1 The present list includes all equipment tested and approved up to and including April 1, 1931.

Sep 1, 1931

By L. D. Gehi, A. W. Khair, M. Ahmad

"Bit wear presents problems to mining operations because it affects both productivity and economics. Most bit research deals with energy requirements and energy dissipation mechanics for ideal fragmentation during the cutting process.Mechanical cutting leads to dust generation. Past studies involving dust generation due to bit wear concluded that dust concentrations increased considerably after a 7% bit weight loss: leading researchers recommend that the bits be changed at that point.Bit wear is affected by three factors: machine operating parameters in-situ mining conditions and rock properties. Operating parameters such as the depth of cut tool material spray position and the drum's rotating velocity are very important and have a definite impact on bit wear.During the mining process the amount of rock in coal and the strength of that rock is important as abrasion and adhesion take affect. Diffusive wear or deformation becomes dominant only when the temperatures exceed critical. Temperatures rise as a function of drum velocity rock properties and the cutting tool itself.Miner bit surveyIn this study, 15 mines were surveyed, and of those six responded for nine seams. The survey reflected a wide range of information about coal production and bit consumption from continuous miner sections. Also used bits were collected to get first-hand information to analyze wear."

Nov 1, 1995

By R. V. Ramani, C. B. Manula, A. Owili-Eger

All the input data required to operate the ventilation simulator except the title, are entered with I10 or F1O.O formats. The title is entered with (18A4) format. The floating points are designated by (FP) and the integers by (INT)

Jan 1, 1975

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

Researchers with the National Institute for Occupational Safety and Health (NIOSH) have developed a training module to educate both new, inexperienced miners as well as veterans on important issues related to self-rescue and escape procedures. These include: (1) physical and environmental conditions that can be encountered in a mine after a major explosion, (2) knowledge of emergency meeting locations and escape routes, (3) the importance of using self-rescuers, even in seemingly clear air, to keep the lungs isolated from contaminants, and (4) why miners should not go off to look for others who are missing. In addition, the module may stimulate miners to think about and discuss mine explosions and the devastating effects of such an event.

May 1, 2009

By Geo S. Rice

"Three men lost their lives in the Black Diamond Coal Mine near Seattle, Wash., recently while wearing oxygen breathing apparatus. The press dispatches stated that these men lost their lives while practicing with the apparatus. Later reports stated that the men died while attempting to make a trip 1200 feet down a 25 degree slope which was filled with black damp, in order to measure the amount of water that had accumulated at the bottom of the mine, and the trip was attempted with oxygen in the tanks of the apparatus with dials indicating only 45 minutes supply. The oxygen in the tank was used up and the men therefore lost their lives from a deficiency of air to breathe.In spite of all the education and training done by the Government to prevent accidents, men are prone occasionally to take unnecessary chances. Every piece of apparatus, no matter how perfect, has its limitations. The Government, through the agency of the Bureau of Mines, has trained many thousands of miners in the use of mine rescue apparatus. The training has been given to all miners who requested it, and the Bureau has gone to the extreme of urging miners to join the rescue and first-aid classes. In spite of all the efforts of the Government, men occasionally attempt the impossible."

Jul 1, 1920

By D. Harrington

Examination of numberous disasters , such as fires or explosions , and the evidence at coroner's inquests following such disasters in several States , have shown the writer how frequently men in charge of the operation and safety of mines have forgotten, or have failed to learn , details of safe mining practices , After securing a position of trust as superintendent , or a certificate of competency to act as shot -firer , fire boss , or mine foreman, some men seem to have felt it unnecessary to keep safety principles in mind , or to keep abreast of current progress in safety ; they have concentrated on getting out maximum tonnage at minimum cost . • In coroner's inquests , the testimony after disasters has shown that firebosses , foreman , and coal -mine superintendents are noticeably lacking in knowledge of the provisions of the State mining law relating to fans or doors , frequency of crosscuts , nature of stoppings necessary , electrical equipment , records of daily mine examinations , quantity of air required , or splitting and overcasting .

Jul 1, 1922

By W. C. Phalen

"The term ""manjak"" is applied to a variety of bitumen or solid hydrocarbon occuring on the Island of Barbados, West Indies, and in Utah, Cuba, and Trinidad. The deposits on the latter island are found within a distance of three miles of San Fernando, the second largest town on the Island, and within three miles of the famous asphalt lake.In chemical composition, manjak is like asphalt. It is almost pure bitumen. Its melting point is, however, more than 4000F. whereas asphalt melts at 1000F. In composition, it consists of 80 to 90 per cent carbon, the balance being chief¬ly hydrogen, with a small quantity of sulfur. It resembles coal in appearance, is odorless, hard, and brittle. It is found in thin beds between layers of clay.The island of Trinidad is rich in this mineral resource. Its development has as yet hardly begun, and the exportations already made have been with the view of testing out the ma-terial. During 1918, exports to the United States were valued at about $3100, and in 1919, up to October 1, they totaled 41 tons, valued at $1900. Prior to 1900, manjak was mined on a small scale in Trinidad, but for various reasons, very little was done between 1900 and 1913. In the latter year, mining operations were resumed by the Trinidad-Tarouba Oil Development Company, of San Fernando. At the present time, there are five shafts, one of which has reached a 37 foot bed of manjak at a depth of 400 feet. Operations could be greatly extended if there were a greater demand for the material.It has not been found profitable to export manjak from Trinidad in the crude state as the price received, namely $35 per ton, hardly covers mining expenses. These are increased by the necessity for careful and thoro timbering on account of the clay formation.Compounds, made by combining manjak with mineral oil command fair local prices which have enabled mine operations to proceed at a profit. Experimentation is still in progress with different mixtures of manjak and oil for various purposes. The manjak, recently sent to the United States was for the purpose of ascertaining whether American oils would be more economical and useful for mixing with the manjak than the Trini¬dad oils. It is the plan to erect a plant very soon for the manufacture of a variety of manjak paints and compounds.Manjak is rapidly increasing in use, particularly in connection with the oil industry. It is produced in close proximity to the oil wells in Trinidad. It is boiled with oils at high temperatures and converted into compounds and paints for nearly every purpose where a preservative is needed, for example, on pipe lines, boilers, chimneys, and miscellaneous iron ware, machinery, etc. It is usually applied in the liquid state, hardening into a tough, rubberlike coating. It has low viscosity, and is not affected by ordinary heat. It makes an excellent insulating material and is impervious to both air and water. In hot and damp climates, like that of Trinidad where pipe lines quickly deteriorate, their life has been pro-longed for extended periods when painted with this material."

Nov 1, 1919