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By P. A. Kennedy

An environmental assessment or impact statement for onshore waste disposal under the Notional Environmental Policy Act is expected to occur with the development of commercial deep seabed mining. An environmental assessment was conducted in order that testing and refinement of nodule waste disposal techniques can he completed prior to 1988, when commercial seabed mining can begin under U.S. legislation. Within this study three classes of process and four classes of waste disposal technique were identified, and five sites were selected as representative of first-generation nodule operations. Each realistic site/process/disposal technique combination was compared against potential effects to determine important characteristics of the rejects and the sites. Regulatory requirements were also considered at each site to identify important issues and their effect on the permitting process. Principal conclusions in the report are the following: (1) uncertainties exist in the regulatory regimes for hydrometallurgical process tailings, primarily regarding classification as hazardous waste; (2) slogs from nodule processing are expected to be inert and relatively easy to dispose of at all sites; and (3) additional physical and chemical information on properties of rejects from all processes is necessary to predict environmental effects.

Jan 1, 1982

By Andrew M. Leszcykowski

A 1981 U.S. Bureau of Mines investigation indicates the Panamint Dunes Wilderness Study Area (WSA) has one active (intermittent) mine,--borrow pit MS 242 owned by the California Department of Transportation (Cal Trans). This mine produces cinders for road base and traction grit. It contains about 900,000 tons of inferred reserves. Examination and sample analyses indicate the Panamint Dunes deposit, covering about 480 acres of the WSA, may have silica resources and the Green Quartz Claim may have copper resources. Carbonate rocks occur in the WSA, but stone resources have not been identified. Adjacent to the WSA, the Big Four Mine contains 35,000 tons of inferred subeconomic zinc-lead-silver resources, and may have additional resources. Sample analyses indicate the Apple 1 Claim, also adjacent to the WSA, may have silver-lead-zinc resources.

Jan 1, 1985

By A. C. Johnson

This report describes exploration, development, and exploitation methods, and summarizes costs at the Stormy Day mine, which was discovered in 1941. Several shipments of tungsten ore were made in 1944 to the Metals Reserve Company, Salt Lake City, Utah. The purchase of tungsten by the Federal Government, which began in 1951, stimulated interest in tungsten, and a successful program of exploration with participation of the Defense Minerals Exploration Administration (DMEA) indicated enough ore to warrant development of the property. Development work comprised drifting, crosscutting, and raising. Shrinkage stoping was used for mining the ore. Operations were suspended in October 1956, when the Federal Government terminated its purchase program. Total production of the mine was approximately 20,000 tons of tungsten ore. INTRODUCTION This information circular is one of a series, prepared in cooperation with various mining companies and published by the Bureau of Mines, relating to methods and costs of equipping and developing mining properties in the United States.

Jan 1, 1958

By Joseph Cervik

Coal is a soft and brittle material. Drilling rates in the Pittsburgh coalbed using a drag bit exceed 3 ft/min at 2,500-pound thrust. However, maintaining the bit on a horizontal trajectory or parallel to bedding planes to attain lengths of 1,000 feet is difficult. This Bureau of Mines report presents a drill string configuration that can be guided through the coalbed. The angle of the borehole is measured periodically and by proper combinations of bit thrust and rotational speed (r/min), bit trajectory can be lifted or dropped to keep the bit in the coalbed. An example of a hole drilled to 2,126 feet is presented to show levels of thrust and rotational speed used to lift or drop the bit, the seemingly unexplainable events that occur, and the strategy used during drilling. Thrust levels during drilling range from 600 to 2,500 pounds. Hydraulic motors powered by a 30-hp, 440-volt motor provide ample power for drilling horizontal holes 2,000 feet long.

Jan 1, 1975

By Robert L. Chufo

The U.S. Department of Energy Pittsburgh Research Center,1 has developed and field tested a spatial, spectral sensor for measuring the thickness of mineral deposits. Knowledge of the dielectric constant of the material is not necessary because the electrical properties of the media are determined automatically along with the thickness or distance measurement. The technology was developed to measure the thickness of coal remaining in the roof and floor of a mine or the thickness of a coal pillar remaining between two mining entries for the purpose of guiding a mining machine. However, field tests have shown the new technique is equally valuable for measuring the thickness of each layer in a multilayer manmade structure such as highway paving or building foundations and the thickness of geological deposits other than coal, such as, salt, granite and sandstone. The noncontacting electromagnetic technique uses spatial modulation created by moving a simple dipole sensor antenna in a direction along each axes to be measured while the complex reflection coefficient is measured at multiple frequencies over a two-to-one bandwidth. The antenna motion imparts spatial modulation to the data and enables frequency domain signal processing to solve the problem of media, target and antenna dispersion. The technique overcomes the problem of multipath reflections from nearby metal structures and avoids the use of radio frequency absorbing material. In its present form the system measures material thickness of zero to over 3 m to within ±2.5 cm accuracy. The system parameters are variable to suit the application but for most applications default values of 40 cm antenna motion with measurements made at 401 frequencies from 0.6 to 1.4 GHz at each of 32 antenna positions with a power level of 0 dBm or less are more than adequate to provide a satisfactory signal-to noise ratio. In the range of 0 to 10 m the system operates in the continuous wave mode and by simply turning off the transmitter for ranges beyond 10 m the problems of time domain processing are entirely avoided. The technique can be implemented with a vector network analyzer, a servo controlled L-band antenna positioner, an IEEE488 bus controller and a process computer. An electronics package designed and constructed to operate in the harsh mining environment and providing 1, 2 or 3 dimensional image presentation is being evaluated as a replacement for the network analyzer. Key words: Ground penetration radar, Spatial, Spectral

By Richard A. Busch

Inadequate engineering design criteria for coal refuse embankments has allowed hazardous impoundment structures in coal mining areas to be created. A necessary first step to develop adequate design criteria is the determina¬tion of basic, respresentative physical property data on the materials that constitute typical refuse embankments. An extensive field and laboratory program was undertaken by the Federal Bureau of Mines. Much physical property data was generated. Additonal petrographic analysis and large scale triaxial compression testing was performed by others. The data presented here should aid in establishing design parameters for coal refuse embankments

Jan 1, 1974

Develop a mobile manipulator that one person can use to lift and maneuver 50- to 600-pound loads. It can be used in maintenance shops and mines to reduce lifting accidents (Figure 1 and 2). Background Lifting heavy items is one of the leading causes of injury in the workplace. Mine Safety and Health Administration statistics showed that, in 2004, back injuries accounted for over 20% of all injuries (1,699 cases) and resulted in 110,000 lost days of work. Forty-one percent of those injuries resulted from materials-handling or maintenance activities.1 In addition to back injuries, lifting injuries include hernias, ruptures, sprains, and strains resulting from losing control of the item being lifted. Factors associated with accidents are weight of the item being lifted, awkward postures, inadequate handholds, and the working environment itself. High accident rates were noted when lifting items that ranged from 50 to 600 pounds, particularly in tight working quarters where maneuverability was critical. Research indicated that a mobile lifting arm would eliminate many lifting accidents in environments where other lifting devices (fork lifts, overhead cranes, mobile A-frames) would not be practical. NIOSH has built a first-generation mobile manipulator unit designed to be used on hard, level floors such as in a shop. The complexity of motion, number of moving parts, compact design, and design constraints of the manipulator required advanced computer-aided design work (Figure 3). As a result of the design work, thirty-eight claims are included in the patent applications. NIOSH will be conducting field trails and working with manufacturers to put the manipulator into industrial use.

Dec 1, 2006

By R. A. Vik

The influence of thermal treatments on the grindability of low-grade hematitic iron ores from Michigan and Minnesota was examined in bench-scale tests. Treatment factors were roasting temperature, roasting atmosphere, and ore cooling conditions. Bond ball mill grindability and work indices were used as response indicators in evaluating the condition of the ore. Of the three treatment factors evaluated, roasting atmosphere, which brought about the con version of iron oxides to magnetite, had the most significant effect; roasting temperature had the next most important effect; and cooling condition had the least effect. Optimum grindability was obtained with reduced-quenched products of both ores at 650° C, near the alpha-beta phase transformation of quartz.

Jan 1, 1971

By Brian G. White

Two examples of en echelon mining-induced fractures seen in hard-rock mines provided a basis for inferring that fracture zones and bedding plane separations immediately surrounding mine openings are promoted by oblique shear into the openings. It is hypothesized that initial fractures or separations form at the corners of openings as a result of high stress and physical constraint on the rock's ability to deform elastically toward the opening. These conditions result in a locally preferred direction of shearing. The shearing, in turn, generates tensile stress that initiates a progression of systematically offset fractures approximately parallel to the direction of greatest compressive stress. The fractures or bedding separations create tabular rock layers that amplify shearing displacement through bending and dilation. Such shearing effectively reduces and redistributes the compressive stress, but significant dilation is an inevitable consequence. The combination of dilation and shearing and the progressive development of fracture zones have important implications with respect to ground support. The concept of mining-induced fractures forming as a result of shear is illustrated by two examples from coal mines. First, fractures seen at longwall faces probably result from shear associated with subsidence. The fracture zone that develops approximates or possibly defines the draw angle of subsidence. As the face advances, fractures extend downward along the lower edge of the fracture zone, while upper extensions of the fractures are pressed closed. Fracture zones in entry roofs provide a second practical example. Here, mining-induced fractures typically follow bedding planes. The shear zone model suggests that the first bedding separations develop near the edges of the roof and successive separations progress upward and toward the center. However, if the direction of greatest stress is inclined with respect to the roof, a fracture or bedding separation zone may propagate from one side only and also extend higher. Because coal ahead of the face provides some support against lateral shear deformation, bedding separation is inhibited near the face. Rock bolts installed close to the face ultimately become more strained and bent than bolts installed a few meters from the face, and bolts installed through the more remote part of a separation zone may ultimately experience the greatest tensile and bending strains. This model is supported by field data documenting progressive bolt failures that rapidly propagated downward across the roof during face advance.

By Frank E. Chase, John L. Ellenberger, Christopher Mark

The nature of competition in the coal market tends to deplete the most favorable coal reserves first, and forces subsequent development of mines in more extreme ground conditions such as those associated with multiple-seam mining. In fact, 70% of the United States coal reserves are in multiple-seam situations. The National Institute for Occupational Safety and Health (NIOSH) is conducting research to develop mine design algorithms that will result in safer multiple seam mines. This paper presents an overview of multiple seam issues in the central Appalachian coalfields. To date, more than 50 case histories have been analyzed from 20 operating mines in Eastern KY, Western VA, and Southern WV. Each case history is classified according to the degree of multiple-seam interaction, ranging from no apparent interaction to severe interaction with direct impacts on mine safety and resource recovery. The case histories are also examined with regard to amount and geologic characteristics of interburden and overburden, and design stability factors. The sequence of mining has also been found to be critical when the lower seam is fully-extracted. This paper compares current case histories to traditional rules of thumb. In addition two situations were modeled using LaModel software. LaModel has been upgraded to import pillar grids and topographic data from AutoCAD files. The cases presented demonstrate vertical stress capabilities of LaModel.

By Daniel Edelstein

Demand for arsenic trioxide increased markedly during 1984 as a result of increased use of arsenical wood preservatives and increased use of arsenicals in agriculture. The increase in agricultural demand was due to a return to production of land with-held from cotton planting under an agriculture program for acreage diversion for some 1983 crops. Supplies of arsenic trioxide were more than adequate to meet increased demand, and prices either declined from, or remained at, the low 1983 levels. In June, ASARCO Incorporated announced plans to close its Tacoma, WA, smelter by mid-1985. Domestic Data Coverage.-Refined arsenic trioxide was produced by two U.S. companies. The major producer voluntarily reported its production to the Bureau of Mines, but to prevent disclosure of proprietary data, the production data have been withheld.

Jan 1, 1985

By M. Viswanathan, M. J. Jorgensen, N. K. Kittusamy

Operating heavy construction equipment is often associated with elevated rates of low back discomfort (LBD). However, there have been few formal studies that dealt with evaluating controls that can reduce the LBD among these workers. The objective of this study was to determine the effectiveness of using a continuous passive lumbar motion system (CPLMS) in reducing low back discomfort among operators of heavy earthmoving equipment. The CPLMS is an additional seat support that has a lumbar support bladder and a pump to provide cyclic inflation and deflation. Two groups of operators were identified as potential subjects for this intervention study, the intervention group with a mean age of 41.2 years and experience of 9.7 years used the CPLMS, and the control group with a mean age of 37.5 years and experience of 7.6 years did not use the CPLMS. Body part discomfort surveys were collected from both groups. In addition, the intervention group completed a CPLMS preference survey. The body part discomfort survey was collected up to eight days at three different times of the day. Results from the body part discomfort survey showed a decreasing trend the longer the CPLMS was used, for both the upper and low back region. A decreasing trend for the low back was also found comparing morning to evening discomfort scores across the days when using the CPLMS. When compared to their regular seat, 54% of the operators felt very comfortable in using the CPLMS, 36% of them wanted one for their equipment, and 54% showed interest in experimenting with the CPLMS for a longer time period. Results from this study indicate that the use of a CPLMS can effectively reduce the low back discomfort experienced by operators of heavy construction equipment.

By John A. Kiefer

Ground fault and overcurrent protection criteria for coal mine a.c. distribution systems were examined under a Bureau of Mines funded investigation. The report begins with a literature review which discusses relaying topics including instrument transformers, ground-fault pickup methods, static relaying, and comparison of relaying techniques. A chapter on ground-fault relaying provides recommendations for maximum and minimum pickup levels as a function of maximum ground current and power system line-to-ground capacitance. Research in the area of phase overcurrent protection has resulted in a complete set of procedural recommendations for the selection and setting of overcurrent relays and current transformers, molded-case circuit breakers, and distribution system fuses in coal mine power systems. The final chapter, which discusses relay system maintenance, introduces a unique test set which was developed by KETRON and used to test the performance of relaying systems in coal mines.

Jan 1, 1980

By P. S. Haury, Thomas C. Denton

"INTRODUCTION AND RESUMEThe Reward zinc property was one of the first selected for exploration by the Bureau of Mines at time when zinc supplies for war production were very short. Preliminary examination indicated that an appreciable tonnage of zinc that could be developed for early production might be found by diamond drilling. The geology was mapped by the Federal Geological Survey, and 14 holes were diamond drilled by the Bureau of Mines. This work was started in September 1942 and completed in September 1943.The Reward is an old property in southwestern Pinal County, 26 miles from Casa Grande on the Southern Pacific Railroad. Mining was begun in the early 1880's and was continued intermittently by several operators to about 1917. About 400,0oo pounds of copper was produced from the north¬eastern part of the property, mainly from a 600-foot incline in oxidized copper ore that replaced a bed of limestone. This ore was mined out. A 400-foot vertical shaft in the copper area was inaccessible. A 325-foot vertical shaft had been sunk near the southwest end of the zinc-bearing area, and a 600-foot crosscut tunnel had been driven near the northeast end of the zinc area, but little zinc ore was produced. There were several shallow inclines and numerous surface pits between the main workings.The ores were deposited in Paleozaic limestones that strike northeast and dip about 40 degrees northwest. These are capped by Cretaceous clastic and volcanic rocks in the zinc area. The outcrops show mineralization in a segment of the limestone 4,500 feet long, which is limited by large cross faults at each end. Another large fault, which strikes north, separates the northeast third of the mineralized belt from the remainder. Copper predominates northeast of this fault and zinc southwest of it. The ore beds are cut by numerous small cross faults. Ore was deposited for short distances along some of these, but more of it made out from the fissures along certain replaceable limestone beds."

Nov 1, 1946

By R. R. Sayers

"According to the dictionary,3 an accident is an event that takes place without one's foresight or expectation, often an undesigned, sudden, and unforeseen occurrence of an afflictive or unfortunate character. However, actual experience with accidents, the second most important cause of death in the United States,4 and a more extensive and scientific inventigation of their causes indicate that from 75 to 90 per cent of accidents are avoidable.5 This is borne out by the results of a three-year study of the accident records of 64,000 motor vehicle operators in New York6 which show that certain drivers are prone to accidents, that accident experience is traceable to certain causes, and that accidents don't just ""happen,"" It is estimated that 97,000 persons were killed by accidents in the United States in 1929 and 15,000,000 were injured. Of these about 23,000 deaths were due to so-called industrial accidents. In a list of accident rates by industries, compiled by the National Safety Council7 from reports of member establishments, mining heads the list, in both frequency (74.43 per 1,000,000 man-hours worked) and severity (9.9 days lost per 1,000 man-hours worked). These figures are very much higher than for any other industry; theindustries showing figures most comparable to mining are meat packing with a frequency rate of 55.94 and a severity rate of 1.47, construction with a frequency rate of 50.41 and a severity rate of 4.62, and refrigeration with a frequency rate of 43.35 and a severity rate of 3.04.While there is no way to determine the actual cost of all accidents from a monetary standpoint, estimates indicate that the cost will run into hundreds of millions of dollars annually.Cost of accidents in metal mines.- The United States Bureau of Mines obtains accurate figures on the number of lost-time nonfatal accidents as well as fatal accidents in the metal-mining industry.8 In 1926 the metal mines employed 127,823 men; 430 men were killed and 30,350 men received lost-time but nonfatal injuries as a result of accidents. Each of these fatal and nonfatal injuries averaged 114 days lost time, computing a fatality as 6,000 days lost time. This is equivalent to 3,523,944 days time lost due to accident, or at $5 per day per man, to a wage loss of $17,619,720. Deducting one-ninth of this figure for compensation paid, the metal miner loses in wage annually about $15,700,000, or about $122 per individual. This average loss per individual includes the cost of fatal accidents reckoned at 6,000 days or $30,000, but even if the loss in time due to fatal accidents be deducted, the average cost to each individual metal miner each year for nonfatal accidents is about $32. Estimating the loss to the metal-mine employer as about the same as that to the employee, the annual cost of metal-mine accidents to the employer is about $15,700,000 and to the employer and miner is $31,400,000."

Oct 1, 1930

By James P. Ulery, Stephen J. Kravits, William P. Diamond

This report presents results of a cooperative research project between the U.S. Bureau of Mines and Beth Energy Mines, Inc. Four coreholes (two before mining and two after mining) were drilled at a longwall mine operating in the Lower Kittanning Coalbed to obtain coal and rock samples from overlying strata to determine their gas content at various times in the mining cycle. The results of those tests indicate that 91 pct of the gas removed from the overlying strata came from coalbeds. Material balance calculations were made to compare the volume of gas produced both from gob gas vent holes drilled on the panel and gas removed by the mine's ventilation system with the volume of gas removed from strata directly overlying the panel to a height of 275 ft. This analysis indicates that only 40 pct of the total gas produced from the panel actually came from the strata directly overlying the panel. The remaining volume of gas production probably migrated to the Iongwall gob from overlying, and perhaps underlying, strata immediately adjacent to the panel and perhaps from greater distances downdip because of the establishment of a long-term pressure gradient in the study area.

Jan 1, 1992

By James P. Ulery, Frank E. Chase

Clay veins found in coal mines have caused numerous injuries and fatalities. These structures plague all phases of mining, including entry development, pillar recovery, and panel extraction. Clay veins also increase production costs and may disrupt or halt mining. These detrimental aspects have prompted the Bureau of Mines to investigate the physical characteristics of and roof instability problems associated with clay veins. This was accomplished by observing and mapping clay veins in surface and underground mines. The occurrence and origins of clay veins were also investigated to determine predictive capabilities. The investigators found that clay veins normally occur in more stable, less rapidly subsiding coal basins. Clay veins result when tensile stresses develop fissures which are later infilled. These fissures can be propagated by compactional processes and/or tectonic stresses active during and subsequent to coalification. The Bureau also found that associated faults, fractures, and slicken-side planes commonly parallel clay veins and disrupt the lateral continuity of the immediate and, sometimes, main roof. When clay veins parallel or subparallel the direction of face advance, the roof is segmented into cantilever beams, causing unstable conditions. Consequently, the strata on either side of the clay veins should be bolted and strapped together to form a beam.

Jan 1, 1987

By Kristine M. Krajnak

Occupational exposure to hand-arm vibration through the use of powered hand tools can result in reductions in tactile sensitivity, grip strength and manual dexterity. In fact, even acute exposures to vibration cause shifts in vibrotactile thresholds in exposed fingers (2,4,5). Although reductions in tactile sensitivity after acute vibration exposures are transient, cellular changes associated with this shift in sensitivity could lead to the more permanent reductions in tactile sensitivity that are a common symptom of hand-arm vibration syndrome (HAVS). Methods Animals. Male Sprague Dawley rats (6 weeks of age) were used for all experiments. Animals were housed in AAALAC accredited facilities, and all procedures were approved by the NIOSH Animal Care and Use Committee and were in compliance with the CDC guideline for care and use of laboratory animals. Vibration exposures were performed by restraining rats in a Broome-style restrainer, and securing their tails to the vibration platform using 6 mm wide straps that were placed over the tail every 3 cm. Restraint control animals were treated in an identical manner except that the tail platform was set on isolation blocks instead of a shaker. Tail temperature and current perception thresholds (CPTs). Rats were exposed to 4 h of tail vibration (125 Hz, 49 m/s2), or restraint. Tail temperature was collected prior to and immediately following the exposure using an infra-red camera. Sensory neuron function was assessed by measuring CPTs with a Neurometer (Neurotron, Baltimore, MD). Transcutaneous nerve stimulation was applied to the C10 region of the tail. Three frequencies were used to test specific fiber types (5 Hz – C, 250 Hz - Ad, and 2000 Hz – Aß). The intensity of the stimulus was automatically increased in small increments until the rat flicked its tail. Tests at each frequency were repeated until the animals displayed 2 responses that were within 2 CPT (or 0.02 mA) of each other (2-4 tests/animal). CPT tests were performed prior to the exposure, immediately following the exposure, and 24 h after the exposure. Data Analyses. Temperatures were analyzed using a one-way ANOVA with animal as a random variable. ANCOVAS were used to analyze the CPTs at each frequency. Temperature at the time of the CPT test was used as a covariate, and animal was used as a random variable Results Tail temperatures declined between pre and post exposure (F(1,25) = 62.85, p < 0.001; mean ± sem pre 25.96°C ± 0.42, post 20.71°C ± 0.77), but were back to baseline levels by 24 h after the exposure in both groups of rats. The ANCOVAs demonstrated that exposure to a single bout of vibration did not alter sensitivity of C (5Hz) or Ad (250 Hz) fibers to stimulation.

Jan 6, 2006

By Ted C. Briggs

Equations for the elastic pressure distortion of the volumes of a Burnett compressibility apparatus are developed and presented in this report for volumes under internal and external applied pressures. An experimental method for the determination of the external pressure distortion coefficients is presented. Young?s modulus and the internal-pressure distortion coefficients are computed from the experimentally determined external-pressure distortion coefficients. The temperature dependence of the pressure distortion coefficients and of Young&apos;s modulus is evaluated for the temperature range 0° to 80° C.

Jan 1, 1968

By L. Nahai

THE OUTPUT ff the mineral industry in 1964 in both non-Communist and Communist Europe showed an upward trend for most countries in keeping with the higher index of overall industrial production. Comparable indexes of mineral industry production for non-Communist and Communist Europe (including the U.S.S.R. in Asia) are not available, primarily because the U.S.S.R. does not report details of its industrial production by industrial sectors. However, available data both in the form of index numbers on production published by the United Nations and based on data as reported to the United Nations by the various countries, and actual production data for selected major commodities published by the various European countries reflect generally expanded output by both the extractive sector and the processing sector of the mineral industry in most of the 26 nations of Europe.

Jan 1, 1966