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By Kim M. Cornelius

Musculoskeletal injury is a term used to describe a wide range of soft tissue disorders which affect the nerves, tendons, and muscles. Common examples include lower back pain, tendonitis, and carpal tunnel syndrome. The majority of these injuries are not the result of sudden mishaps, but usually develop gradually from repeated wear and tear. Symptoms may first appear after weeks, months, or even years. Symptoms may result from many types of activities, performed at work or at home, and it is often difficult to attribute a single event. In fact, it is more common to identify the factors which may have contributed to the development of the condition. The terms repetitive strain injuries or cumulative trauma disorders (CTDs) have been commonly used to refer to disorders that have occurred due to work related activities (Putz-Anderson, 1988; Fraser, 1989). Three main risk factors contribute to CTDs: force, repetition, and awkward postures. Any one or combination of these may contribute to the development of CTDs. Therefore, the design of equipment in conjunction with the required tasks should attempt to reduce these risk factors. Examining the layout of the work area to help identify tasks which may contribute to cumulative trauma is necessary. The following list(Putz-Anderson, 1988), describes ergonomic concerns that, overall, should be minimized at the work area:

Jan 1, 1997

By R. L. Gall

This report describes Bureau of Mines experiments in gasifying coal in a helium-heated tube-coil reactor. The purpose of this work was to investigate helium as a medium for transferring heat from a nuclear reactor to gasify coal or for use as high-temperature process heat. A laboratory-scale system was designed and constructed to demonstrate feasibility. In preliminary tests with this system, in which the coal was fed as a water slurry, the helium-heating and recycling equipment operated well. Considerable difficulty was experienced, however, in preheating coal slurry to the desired range of 400° - 1,000° F. without plugging the preheaters. Five different preheaters plugged with coke or with salts leached from the coal. The longest operating period wan 12 hours. These difficulties were partly due to the relatively small equipment and flow rates. The gasifier processed l pound per hour of low-rank coal at 300 p.s.i.g. and 1,800° F., with the carbon conversion limited to 20 to 30 percent by the short residence time and slow heat-transfer rate.

Jan 1, 1962

By Andrew M. Leszcykowski

In 1985 at the request of the Bureau of Land Management, personnel from the U.S. Bureau of Mines examined a 27,680-acre portion of the 30,420-acre King Hill Creek Wilderness Study Area (10-19-2) in order to evaluate the mineral resources. The study area, in southwestern Idaho, is underlain by Tertiary tuffs and basalt. There are no known mining claims or prospects in the study area, and no mineral resources were identified. The Volcano mining district is immediately north, but mines there are in granitic rock which does not crop out in the study area. Oil and gas leases were offered for land in the southern part of the area, but no applications were filed, and the lease offering was withdrawn (1985). INTRODUCTION This report describes the USBM (U.S. Bureau of Mines) portion of a cooperative study with the USGS (U.S. Geological Survey) to evaluate mineral resources and potential of the King Hill Creek study area at the request of the BLM (U.S. Bureau of Land Management). The USBM examines individual mines, prospects, claims, and mineralized zones, and evaluates identified mineral and energy resources. The USGS evaluates potential for undiscovered resources based on areal geological, geochemical, and geophysical surveys. Results of the investigations will be used to help determine the suitability of the study area for inclusion into the National Wilderness Preservation System. Although the immediate goal of this and other USBM mineral surveys is to provide data for the President, Congress, government agencies, and the public for land-use decisions, the long-term objective is to ensure the Nation has an adequate and dependable supply of minerals at a reasonable cost.

Jan 1, 1986

By Eric E. Cather

A mineral survey of a portion of the Lake Eleanor RARE II area (No. 5807), Trinity County, California, was done by the U.S. Bureau of Mines and U.S. Geological Survey (USGS). Approximately 8,650 acres (3,500 ha) of the Lake Eleanor RARE II area not examined for this report had been previously investigated by U.S. Bureau of Mines and U.S. Geological Survey personnel and published as part of USGS Bulletin 1371-B, (Hotz, 1972) Mineral Resources of the Salmon-Trinity Alps Primitive Area, California. The report showed that the section included in the rake Eleanor RARE II area contained no metallic mineral resources. Geochemical sampling indicated that the Lake Eleanor RARE II area contains no potentially important mineral resources. About 4,650 acres (1,880 ha) of the eastern part of Lake Eleanor RARE II area were examined for this report. The Bureau of Mines was responsible for detailed examination and sampling of mines, prospects, and mineralized zones; the Geological Survey conducted geological, geochemical, and geophysical studies of the area. This area is underlain mainly by granitic rock and serpentinite.

Jan 1, 1981

By G. A. Apell, E. G. Howe, S. W. Hazen

"INTRODUCTION As a small amount of manganese was produced from the Lake Valley mining district of Sierra County, N. Mex., during the First World War, the district was reexamined in March 1941 by John H. East, Jr., an engineer of the Bureau of Mines, as a possible source of manganese for use during the Second World War. Preliminary examination indicated a substantial reserve of 25 percent ore, so it was recommended that an exploratory program of mapping and sampling be undertaken by the Bureau.The program was started in the fall of 1941 and was completed the middle of 1942. The project 3/ was divided into two parts: The first, an underground sampling program, formed the basis for the second, or churn-drilling program. Mapping and sampling of old underground workings were begun in October and finished in November 1941, whereas churn drilling was begun in February and completed in June 1942."

Jun 1, 1947

By S. S. Venkata

This volume describes a comprehensive program of research into the reliability of mine electrical power system components and the resultant reliability of the total system. The research effort encompassed analytical models, laboratory testing and field testing. The analytical work included definition of terms, fail rate functions and distributions, failure rate estimation and techniques and procedures for theoretical reliability assessment. One of the primary mine power system components addressed in the study was the ac molded case circuit breaker. This device is known to have low reliability and hence an unfavorable impact on mine safety and productivity. Ac molded case circuit breaker reliability was studied by analytical means, laboratory testing and field monitoring. A similar three-pronged' effort was made to study the reliability of undervoltage relays/releases. Particular emphasis was placed on new solid state undervoltage relays. The reliability of bulk power components, such as trailing cab les, motors, control gear, and other equipment, was assessed by gathering maintenance records from active mines. These data were compared to similar records from other industries. The work was extended to include the reliability, availability, maintainability and safety of these components.

Jan 1, 1979

By J. A. Kost

A dust-control manual was prepared for use by mine operations personnel. The manual documents state-of-the-art control techniques, dust sampling, and use of personal protective devices. Content addresses advantages/disadvantages of control techniques, design and operating specifications, and implementation and maintenance guidelines. An indexed list of selected references is also included. In addition to the completed manual, this report documents work performed in the course of its preparation.

Jan 1, 1981

By L. J. Prosser, Robert Anderson

Advance knowledge of roof conditions can lead to improvement in roof control strategies that will reduce roof falls and ultimately will reduce injuries to mine workers. J.H. Fletcher and Company, in cooperation with West Virginia University, has been developing a system to meet these needs by collecting torque, thrust, and rotation speed data during drilling operations. Recent improvements in analysis algorithms to detect anomalies in the roof structure as well as various display enhancements for real time mapping and evaluation of roof structures have been incorporated into current Fletcher Information Display system. The unit has also been housed in an explosion-proof container to allow use in coal mine applications. Recently, the system has undergone extensive field trials in several limestone mines and one coal mine. During these trials, the National Institute for Occupational Safety and Health assisted Fletcher in verifying the accuracy of the roof mapping capability of the system by comparing the display information to bore hole scoping observations and drill corings. It was concluded from this assessment that the intelligent drilling system can complement scoping and core analysis to provide a more complete picture of roof strata and is capable of seeing features or conditions that are not always obvious in these more traditional methods.

By John J. Sammarco

Abstract- Emergency shutdown systems (ESDs) for mining machinery provide critical functions to safeguard miners. Traditionally, ESDs were realized with simple hardwired circuits; today, there is a growing trend to use programmable electronic technology such as programmable logic controllers (PLCs). This paper describes an analytical study to quantify the safety integrity of a PLC-based ESD and a hardwired ESD. The safety integrity level of each design approach was determined by quantifying the average probability of failure on demand (PFDavg) as described by the recommendations for programmable electronic mining systems published by NIOSH and the IEC 61508 international standard. The safety analyses addressed system architecture, hardware failure probability, proof test interval, diagnostic coverage, and human error probability. The results indicated that a same level of safety, safety integrity level 3 (SIL 3), could be attained when evaluating random hardware failures. Neither approach could attain SIL 3 if manual activation was used. Human error was the limiting factor where, using human reliability analysis, PFDavg < 1 x 10-1; thus, the ESD does not meet SIL 1. It is apparent that automatic verses human¬activation of the ESD is a very important safety consideration. Manually actuated ESDs can only achieve SIL 1 regardless of the technology; therefore, additional independent safety layers of protection are needed to exceed SIL 1. Secondly, it is apparent that the technology choice is very important. The PLC-based ESD was much simpler to design and to validate safety1.

Jan 1, 2007

By Peter Swanson, John Rettkowski

As part of a research program to reduce injuries and fatalities in the U.S. mining workforce, NIOSH is investigating the potential use of noncontact vibration measurements to identify hazardous ground fall conditions. In the present study, the effectiveness of remote vibration sources in exciting resonant responses in damaged structures is examined. Initial experiments were performed on a damaged concrete slab in a controlled environment. Vibration response was measured with a laser Doppler vibrometer using both single-point and two-dimensional array recordings. Excitation sources included direct mechanical impacts to remote portions of the slab and a remotely located industrial demolition hammer. Surficial damage was effectively delineated with both sources through visualization of vibration response in spectral bands selected to discriminate wave propagation from large-scale slab resonance effects.

By F. Keith Shelton

"INTRODUCTION Cobalt is an essential metal in the normal industrial ac¬tivity of the United States. Being an important constituent of high-speed steels and other cutting-tool materials, it becomes of critically essential importance during periods of national emergency. 3/ The Presidential order of December 20, 1940, included cobalt among other essential commodities that could be exported only under license. The Executive order 4/ listed cobalt metal, cobalt oxide, and alloys containing more than 5 per¬cent cobalt as being within the licensing requirements.There was no domestic marketed production of, cobalt products from 1931 until 1940 when the Pyrites Co. 5/ produced some cobalt oxide. The major portion of the domestic cobalt requirements has been obtained from Northern Rhodesia, the Belgian Congo, and French Morocco. 6/ The uncertainty of sea transportation from those sources of supply demanded that steps be taken to obtain from domestic raw materials an adequate supply of cobalt for use in the materials required for production of indispensable machined war metal products. In connection with the national policy for attaining self-sufficiency of strategic and critical materials, the Bureau of Mines, Boulder City, Nev., Experiment Station initiated studies to recover cobalt from the low-grade oxidized cobalt deposits in the Goodsprings district, Nevada. Hewett 7/ reported occurrence of cobalt specifically in the Blue Jay, Columbia, Copper Chief, and Highline mines and generally over a widespread area in the district."

Jan 1, 1946

By Louis E. Dalverny

U.S. Bureau of Mines research to develop diagnostic methods to locate and evaluate fires in abandoned mines and waste banks and techniques to extinguish such fires was applied to an abandoned 60-acre underground bituminous coal mine (Renton, Allegheny County, PA) to locate and extinguish three separated fire zones. Mine fire diagnostics interpret changes from baseline values in subsurface pressures, temperatures, and mine gas composition under imposed pressure gradients induced by a borehole exhaust fan. The effective gas sampling area surrounding each borehole is greatly enlarged. Sampling iterations, using a "communicating" boreholes set, provide "fire signature" information for locating both heated and cold areas. Time-dependent monitoring differentiates heating and cooling periods resulting from combustion front movement and/or fire extinguishment activities. A water injection with fume exhaustion extinguishment effort involved injecting water through boreholes to quench the heated zones while exhaust fans actively removed heated gases from the mine. The technique was ineffective as implemented, primarily because of inadequate spreading of water from the injection points. The Bureau&apos;s diagnostic method determined the fire locations and the effectiveness of the water injection with fume exhaustion extinguishment technique.

Jan 1, 2010

By Stephen C. Tadolini, Thomas M. Barczak, Peter (Yunqing) Zhang

A cooperative study was conducted with Emerald Coal Resources, L.P., an affiliate of Foundation Coal Corporation, and the National Institute for Occupational Safety and Health (NIOSH) to evaluate the effectiveness of (partially) pre-driven longwall recovery rooms supported with pumpable roof supports. This paper evaluates the load transfer mechanics associated with the advancement of the longwall face into the pre-driven recovery room and the widening of the room to recover the longwall shields. The results show that the yielding of the panel fender produced uncontrollable convergence that caused yielding of the shields and stiff pumpable roof supports when the face was approximately 10 ft from the recovery room. The shields continued to yield until the face advanced into the recovery room. Convergence in the pre-driven recovery room typically reached 6-8 in once the pumpable supports yielded and shed load through a declining residual load capacity prior to being cut out by the longwall shearer. Roof deformations occurred beyond the 32-ft horizon with total deformation ranging from 2 to 4 in, indicating that standing support was necessary to help control the span as the longwall face advanced into the pre-driven recovery room. Stability improved as the pumpable supports were cut out, thereby reducing the span between the shields and the outby pillars. In the end, the shields were successfully recovered under stable ground conditions. However, a disconcerting discovery was the load shedding of the outby pillars as the recovery room was mined into. It is postulated that this may be due to the progression of the rear “abutment” moving toward the recovery room as the panel fender and standing support in the recovery room yield and shed load. This behavior was not expected with a relatively narrow room that is fully supported with standing support. If this mechanism is indeed occurring, the width of the room and performance of the standing support becomes even more critical. Premature failure of the support can lead to excessive convergence on the shield line that cannot be controlled even with modern shields, resulting in roof instabilities that can lead to catastrophic results.

By John C. Hartley

Large areas of the anthracite beds in the Wilkes-Barre, Pa., region have been first-mined in such a manner that over half of the original coal has been left underground as pillars to support the overburden. To recover the maximum amount of this remaining coal, improved devices to support the roof while pillars are being extracted are needed. Also needed are suitable backfilling systems that will stabilize the strata during the mining and effectively limit the inevitable subsidence after pillars are removed. Accordingly, the Federal Bureau of Mines furnished 400 yielding steel props that had been purchased abroad, where this type of prop had been used successfully. The cooperating company arranged for concurrent tests with a mechanical stower designed and built by an American manufacturer. In the area in which the experiments were conducted, pillar removal, using conventional timbering, was most difficult because the roof fractured badly, the installation of timbers consumed a substantial part of the work effort, and some coal nearly always was lost. With the application of the yielding props, the time needed for securing the roof was reduced 33.9 percent; production per man-shift was in¬creased over 33 percent; coal recovery was improved more than 9 percent; and the convergence between roof and floor, during mining and backfilling, amounted to as much as 8.03 inches without any break in the roof. However, in September 1953 some roof rock fell in pillar 10 owing to insufficient props in a small area where the ends of three top holes drilled in the coal face extended up into the roof rock.

Jan 1, 1956

By J. Walden, J. Rhoades, R. E. Miller, R. Gibbs, P. Boman

Accelerometers and pressure transducers, mounted in suspension components, can be used to monitor the ride of haulage trucks. Presently, it is difficult to tell what caused a jolt to the truck using either pressure or acceleration data alone. When information from a global positioning system (GPS) is recorded at the same time as shock pressures or acceleration data, the exact location of an event can be determined. Mine management can then determine what caused the jolt to the truck. This research is part of a National Institute for Occupational Safety and Health (NIOSH) project called "Engineering controls for reduction of jolting/jarring injuries in surface mines." NIOSH is investigating how the work environment of haulage truck drivers can be improved. The US Mine Safety and Health Administration (MSHA) notes that, between 1986 and 1995, 60% of the back injuries were to haulage truck drivers in metal/nonmetal surface mining. Personnel from Phelps Dodge suggested that combining acceleration data with information obtained from a GPS could generate results with a variety of uses. Therefore, researchers at the Spokane Research Laboratory (SRL) began investigating how to tie acceleration and GPS data together. It was originally thought that this tool would be used primarily for road and truck maintenance. However, as research progressed, it became apparent that it would also be useful in providing feedback about equipment operations and identifying unusual causes of jolting. Experimental approach Available components that function well by themselves were linked for the purpose of proof of concept. Using a Modular Mining Systems (MMS) product called Vital Signs, SRL researchers took an Aero-Marine Products (AMP) acceleration recorder and hardwired it to MMS Dispatch equipment already installed on a truck. AMP is one of several manufacturers of acceleration recorders frequently used to monitor freight during shipping. MMS Dispatch is used for production accounting and truck dispatching and uses GPS tracking. Through Vital Signs, an analog or digital alarm signal can be recorded. Steve Rhoades, of MMS, wrote unique code that links the Vitals Signs data and GPS location and stores this data in an ASCII log file. SRL researchers installed the equipment in a Caterpillar 793 haul truck. The result was a working prototype. Figures 1 and 2 show the instrument installation in the truck. Discussion From 8:30 pm on Sept. 14, 1998 until 6:50 am on Sept. 15 1998, 899 jolts above a threshold of 2 g (1 g is the acceleration of gravity. It is either 9.81 m/s2 or 32.17 ft/ s2.) were measured on the test truck. Some sections of the haulage road produced most of the events, while

By Alex C. Smith

The National Institute for Occupational Safety and Health (NIOSH) and Northwest Barricade LLC (NWB) conducted a study to evaluate the effectiveness of a novel fire blocking gel for use in underground coal mines to extinguish or to retard the growth of a coal fire. The gel agent was subjected to controlled laboratory testing to assess its ability to delay coal ignition. It was then evaluated to determine if manual fire hose application could be used to apply the agent to mine roofs and ribs to provide a safe egress for mine rescue teams from a fire area. The gel agent was also evaluated in a water sprinkler system to determine its potential for use in conveyor belt fire suppression systems. The agent was then tested in live-fire exercises to examine its effectiveness in retarding and extinguishing a deep-seated coal fire and wood fire. Lastly, the ability of a Mine Rescue Team to quickly and safely apply the gel agent to a mine entry during a simulated mine fire exercise was determined.

Jan 1, 2010

By Leonard J. Prosser, Dennis R. Dolinar, John L. Ellenberger, Gabriel S. Esterhuizen, Anthony T. Iannacchione

The room-and-pillar mining method is used extensively in underground limestone mines in the Eastern and Midwestern U.S. The rock mass is typically a near-horizontal, bedded deposit at relatively shallow depth. A survey of 34 mines was conducted in which data on roof spans, rock mass properties and support practices were collected as part of a National Institute for Occupational Safety and Health research project into ground control in limestone mines. The average room width is 13.5 m (44 ft), accommodating large mechanized equipment. The results show that the immediate roof beam can consist of many individual layers and can contain several near-vertical joints. In spite of the room widths, the roof is naturally stable in many mines. Observed roof instabilities can generally be related to excessive horizontal stresses or unfavorable geological structures that cause block fallout or beam failure of the bedded roof rocks. The survey showed that the rock mass quality of the limestone does not vary significantly throughout the Eastern and Midwestern U.S. Roof conditions and the need for support were found to be closely related to the thickness and competence of the first layer of limestone in the roof. The findings highlight the need to identify local geological structures and the roof beam characteristics so that support alternatives can be evaluated. Monitoring and observational technologies that are available for identifying potentially unstable roof are presented, which include: roof characterization using the Rock Fall Risk Index, automated logging of roofbolt hole drilling, microseismic monitoring and displacement monitoring.

By A. C. Munro

This paper, which describes the milling practice at the Britannia concentrator, Britannia Beach, B. C., is one of a series being prepared by the Bureau of Mines. The concentrator treats copper ore at the present rate of 6,000 to 7,000 tons of dry ore daily and produces copper concentrate and pyrite concentrate by selective flotation methods. The copper concentrate is smelted and the pyrite product is utilized for acid manufacture.

Jan 1, 1932

By Kenneth G. Skinner

Diatomite, also known as diatomaceous earth, diatomaceous silica, kieselguhr, and moler, has been used extensively for many years, but only during the past two decades has it become an important industrial mineral. United States sales for 1.936-38 totaled almost 280,010 tons,7 but relatively little (with the exception of that sold by an Oregon company affiliated with a larger California company) was sold by Pacific Northwest producers. In attempting to develop some of the many Pacific Northwest diatomite deposits, these producers have been handicapped by lack of published technical information regarding processing methods and the suitability of different deposits for specific uses. To determine some of the physical and chemical properties of known Pacific Northwest diatomites, the present investigation was started in 1938 by the Bureau of Mines in cooperation with the College of Mines, University of Washington. Figure 1 shows the location of deposits sampled. Because most relatively pure diatomites can be used as concrete admixtures or as inert fillers in rubber, paints, and plastics, this investigation concentrated upon determining some filter-aid characteristics and their relationship to other physical properties. A filter-aid is a powdered material that, when added to solutions to be filtered, improves flow rate, filtrate clarity, or both. Some chemical analyses also were made.

Jan 1, 1944

By S. H. E. Phillips

This report describes the initial feasibility, the development and the field demonstration of a system for shaft sinking employing a high energy mechanical impact rock breaker and a compatible muck disposal system. The increased shaft sinking rates, decreased costs and improved safety conditions obtainable by the elimination of the less efficient conventional drill-blast-muck cycles are discussed. Four shaft sinking concepts utilizing the impact rock breaker in various shaft configurations are developed and the field demonstration in a rectangular shaft is described. The progress achieved, the problems and their remedies and the proposed modifications to improve the machine are described.

Jan 1, 1978