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By W. A. Calhoun

The purpose of this investigation was to develop economical mineral dressing processes for removing objectionable quantities of impurities, such as quartz and pyrite, from refractory clay deposits in east central Missouri. The presence of excessive quartz in these clays causes crazing. Pyrite causes bloating and unsightly dark blobs on the surface of fired refractory brick. The iron concentration in the proper state of oxidation may also act as nucleation centers for carbon crystal growth which can result in bursting of the refractory. Numerous deposits, representing a very large tonnage, have been examined and prospected by various refractories companies and found to contain impurities in objectionable quantities. Upgrading these clays would greatly extend our reserves of high-quality refractory clays. Wet-tabling and wet-cyclone concentration were found to be effective for removal of impurities from clays. Of the two methods, wet-cyclone concentra¬tion would be cheaper and more effective. Although wet-tabling improved the refractory properties of each clay, beneficiation by wet-cyclone produced clays of superior quality. Clay recoveries by wet-cycloning ranged from 56.1 to 81.8 percent of the weight of the crude samples, and the beneficiated clays contained from 71.9 to 94.4 percent of the total alumina. The pyrometric cone equivalent (PCE) was increased from 1 to 3 cones by wet-cycloning. The beneficiated clays also met the reheat shrinkage requirements on refiring to 1,400° C. Missouri is one of the major domestic sources of fare clay. In addition to deposits of high-grade refractory clays, there arc many deposits that contain small percentages of impurities, which render the clays unfit for the production of high-heat-duty firebrick. Development of methods to beneficiate these submarginal clays to usable materials would greatly increase commercial fire clay resources.

Jan 1, 1961

By Paul C. Hyndman

The U.S. Bureau of Mines investigations of the three subunits (fig. 1) of the Homestead RARE II area (No. 6291) revealed no evidence of mining activity or mineral deposits in the area. The Iron Dyke Mine, 3 mi (5 km) outside the study area produced ore between 1916 and early 1982 from a volcanogenic massive sulfide deposit in the Permian volcaniclastic Hunsaker Creek Formation of the Seven Devils Group. The Hunsaker Creek Formation does not crop out in the RARE II area, but extends into the area beneath Miocene flows of Columbia River Basalt. The abundant basalt in the area could be used as aggregate or dimension stone, but equivalent deposits exist closer to markets. INTRODUCTION Location and Access The Homestead RARE II area (fig. 1) encompasses 6260 net acres (253U ha), in three units, of the Wallowa-Whitman National Forest in Baker and Wallowa Counties, Oregon. Two small units of 160 and 300 acres (65 and 120 ha) are 5 mi (8 km) north and east of the main study area. Homestead, Oregon, on the Snake River, is about 3 mi (4 km) south of the two small areas, and about 3 mi (4 km) northeast of the main study area. Peripheral access is provided by State Highway 86, U.S. Forest Service Road 39, and ancillary roads and trails.

Jan 1, 1983

By E. C. Westman

Three-dimensional velocity tomograms were generated on a daily basis to image mining-induced changes to the overburden above a longwall mine. The hypothesis was that a coherent redistribution of seismic velocity, due to the development of high-stress zones, could be imaged at the mine scale. Seam depth was 360 m and source location depth varied from 100 to 1000 m. Sixteen geophones were distributed over a 600 by 600 m square area on the surface above the mine. More than 12,500 events were recorded over an 18 day period. The recorded seismicity provided input for the local-earthquake tomography code, SIMULPS. Eighteen tomograms were generated and high-velocity regions correlated well with high abutment stresses. Additionally, the high-velocity regions were observed to redistribute as the longwall face retreated. These results indicate that velocity tomography can be used to provide a better understanding of temporal changes within a rock mass, and can potentially be used to produce a better understanding of the mechanisms that lead to unanticipated ground failures.

Jan 1, 2008

By Elaine T. Cullen

Miners, like many skilled blue-collar workers, are not traditional learners. They have not always been successful in classroom-type settings, preferring to learn on the job in a hands-on environment. U.S. law requires that miners have a minimum of 8 hours of safety training annually, plus 40 hours for underground miners and 24 hours for surface miners when they enter the industry. However, miners rarely view this training time positively. In fact, it has been called “safety jail” by many, who regard it as a time to get a little extra sleep While mining has become far safer in the past 100 years, it is still a dangerous occupation. The Office for Mine Safety and Health Research, a part of the National Institute for Occupational Safety and Health (NIOSH), has funded a project for the past 4 years to address this challenge. The purpose of the research was to find a way to develop effective safety training for these people. Miners are born story tellers. They share “near miss” stories, stories about master miners they have known, and stories about how things used to be. These stories not only pass along information about what will happen if a miner fails to respect the mining environment, they also instruct listeners in the culture of mining and the values that it embraces. Stories, it seems, are a way to get safety messages across to miners, especially inexperienced ones, and using older, wiser miners in these stories is an obvious choice. This paper will discuss how a series of training videos was developed, how “master miners” and story lines were chosen, and how the resulting videos have been received in the mining industry.

By C. E. McElroy

"INTRODUCTION The ventilation of working places in mines by jets of air discharged from fan-pipe lines is an important phase of mine ventilation, whether the primary purpose is to dilute gas or dust concentrations or to provide air-motion cooling effect. Jets of similar nature are very prominent factors in the ventilation of enclosed spaces, such as buildings and ships. The effectiveness of such jets depends on the distribution of the air in the jet streams, a subject on which the little definite information previously available applied to jet discharge into large, open spaces under conditions quite different from those ordinarily associated with fan-pipe discharge in mines.The results of an initial series of experiments on the discharge of air from fan-pipe lines in mine openings have been described. 3/ This report presents the results of a second series of experiments and compares the results of both series with theory and experiment on jet discharge into large, open spaces. The results of this second series confirm and supplement those of the initial series, in which a 10-inch pipe discharged into an 8- by 8-foot develop¬ment end through seven short discharge pieces of different designs. In the present series the same 10-inch line was used, but the discharge was through 10- to 30-foot lengths of 5-inch, 10-inch, and 20-inch-diameter pipes and through a 20-foot length of 29- by 3-inch pipe. Tests were made with the air discharged into a closed drift or development end, as in the previous series (in which case the discharged air returned past the end of the pipe) and into an open drift (in which case the discharged air did not return past the end of the pipe but continued out along the drift). Test conditions corresponded to the discharge of a jet into a channel closed at one end; in one case, the discharge was directed toward the closed end and in the other toward the open end. The former typifies fan-pipe ventilation of development ends and the latter an abrupt increase in the sectional area of an airway. In both the flow had to pass from jet to open air against some resistance.The tests were made in the Mount Weather Testing Adit of the Bureau at Bluemont, Va., on the pipe line installed for ventilating the adit, and extended from late September to mid-November 1940. Preparations were made for directly comparable series of experiments on the injector effect of fan-pipe discharge in an open drift and on free expansion in large, open spaces, but these test programs were .first postponed in favor of other work and finally abandoned until the war is over."

Nov 1, 1943

By Robert S. Hedin

Passive methods of treating mine water use chemical and biological processes that decrease metal concentrations and neutralize acidity. Compared with conventional chemical treatment, passive methods generally require more land area, but use less costly reagents and require less operational attention and maintenance. Currently, three types of passive technologies exist: aerobic wetlands, organic substrate wetlands, and anoxic limestone drains. Aerobic wetlands promote mixed oxidation and hydrolysis reactions, and are most effective when the raw mine water is net alkaline. Organic substrate wetlands promote anaerobic bacterial activity that results in the precipitation of metal sulfides and the generation of bicarbonate alkalinity. Anoxic limestone drains generate bicarbonate alkalinity and can be useful for the pretreatment of mine water before it flows into a wetland. Rates of metal and acidity removal for passive systems have been developed empirically by the U.S. Bureau of Mines. Aerobic wetlands remove Fe and Mn from alkaline water at rates of 10-20 and 0.5- 1.0 g. m-2? d-1, respectively. Wetlands with a composted organic substrate remove acidity from mine water at rates of 3-9 g. m-2? d-1?. A model for the design and sizing of passive treatment systems is presented in this report.

Jan 1, 1994

By Douglas Talley

This report describes a 4-inch diameter borehole probe which contains a low light level TV camera, magnetic compass, light illumination source, bottom/water detector sensor and a pointing angle sensor. The camera viewing angle is at a right angle to the probe's body. All data from the sensor is multiplexed into the closed circuit camera video for transmission on a single 50 ohm coaxial cable to a surface control unit. Likewise control of the probe's power, zoom lens, focus, panning and aperture is accomplished via a down-link multiplexed on the same cable.

Jan 1, 1984

Coal, America's most abundant fossil fuel, is expected to play a key role in our pursuit of energy independence. A substantial increase in coal exploitation will be required if we are to fulfill our future energy needs. It is essential that new developments continue if stable coal prices are to be achieved and maintained. The challenge of the mining industry is to continue these developments in the face of problems related to increasing labor costs, inflation and environmental restoration. With expectations of increased activity in surface coal mining, the U.S. Bureau of Mines has authorized this study to determine the preliminary economic and technologic feasibility of underspoil haulage in area strip coal mines and to identify geologic and geographic areas where such a system could be used. These objectives were met by literature search, data-gathering visits to several active area strip mines and by analyzing various haulage systems that were superimposed on three model mines. Potential advantages of such a system include: 1) improved mine design; 2) lower mine operating costs; 3) improved land reclamation; 4) lower manpower requirements; 5) lower mobile equipment requirements; and 6) smaller, less sophisticated maintenance facilities.

Jan 1, 1975

By Dana C. Reinke

Jan 1, 2005

By F. L. Wideman

This report describes a computer program that is used for the calculation of the coordinates and elevations of subsidence survey pins located by intersection. This program was developed for the Federal Bureau of Mines by the Numerical Analysis Laboratory, University of Arizona. These calculations, although relatively simple, are both tedious and time-consuming when computed with a desk calculator and trigonometric tables. In this survey, a large number of pins were surveyed repeatedly, and it was evident that both time and money could be saved by using a digital computer.

Jan 1, 1962

By Fred D. DeVaney, C. W. Ambler

"Copper sulphate is a common flotation reagent for blende ores. Metallic iron also is present in the mill circuit, and a reaction between the iron and the salt would be in accord with well-known chemistry. The abundance of metallic iron in a flotation feed may be noted by even perfunctory examination. First of all the mine contributes metallic iron, then the coarse-crushing machines add their share, and finally the fine-grinding medium its portion. If the grinding is with cast-iron balls the amount of metallics is greater than when steel is used. Thus it is that much more metallic iron is present than would be indicated by noting the ball consumption. An estimate that the total amount of metallics is twice that supplied by the balls and liners might not be far amiss.That copper sulphate plates out on iron in an acid solution is well known, but since flotation is practiced commonly in solutions where acid has not been added this reaction has not been given sufficient thought.This problem has been the basis of a study undertaken jointly by the Mississippi Valley Station of the United States Bureau of Mines and the Missouri School of Mines and Metallurgy, at Rolla, Missouri. Its importance may be understood better when the tonnage of zinc ores now being treated by flotation in this country is considered. According to Gaudin4 5,536,244 tons of zinc or were treated by flotation during 1927. In these operations copper sulphate was employed as an activating agent; the amount per ton averaged 0.81 pound for straight sulphide zinc ores and 1.16 pounds for complex ores. Since such large quantities of zinc ore are treated by flotation and since metallic iron is always present, the importance of studying their reactions on each other and the effect of their reaction"

Dec 1, 1929

By T. J. Batchler, T. M. Barczak

The Code of Federal Regulations (CFR) requires that the transverse load capacity of stoppings be equal to or greater than traditionally accepted in mine controls, which for block stoppings is generally accepted as 39 psf as referenced in the preamble to the CFR standard. This measure is based on physical testing of a freestanding wall in accordance with ASTM E 72 specifications, where our past research has shown that the dominant parameter is the tensile strength of the sealant. A new protocol based on rigid arch loading of the structure is proposed to determine the true transverse load capacity of block stoppings. Arching is achieved by the restraint of the stopping against the mine roof and floor, whereby compressive forces are developed within the wall. A laboratory procedure using the NIOSH Mine Roof Simulator (MRS) to simulate rigid arching of block stoppings was developed and results verified through full-scale in-mine tests. The rigid arch tests have demonstrated transverse load capacities more than an order of magnitude higher than the ASTM E 72 evaluation method from which the 39-psf requirement is derived. More importantly, the rigid arch tests have shown that the load capability is dependent on the physical properties of the block and geometric properties of the wall and not the sealant.

By Thomas M. Barczak

Secondary roof support systems play a vital role in preserving the safety of underground mine workers by preventing the unintentional collapse of the mine roof. Hundreds of thousands of standing roof supports are constructed each year in underground coal mines. Historically, wood and concrete cribs and timber posts have been used for secondary roof support. These support constructions require the handling of heavy and bulky materials, causing numerous injuries to the mine workers and resulting in more than 40,000 lost workdays in the past 9 years. Since 1993, various alternative support technologies have been developed. These new support technologies not only provide superior roof support, but many also have significant material handling advantages by using smaller and lighter weight materials, fewer components, mechanically installed support systems, and pumpable support systems. The National Institute for Occupational Safety and Health (NIOSH) has conducted extensive material handling research and has developed recommended lifting thresholds to reduce material handling injuries. An analysis of roof support construction reveals that conventional support materials used in wood and concrete cribbing exceed the recommended lifting thresholds, while the engineered support systems are closer to the recommended weight thresholds. Finally, recommendations are made relative to proper lifting techniques and material handling practices to prevent injury to mine workers when constructing roof supports in underground coal mines.

Jan 10, 2000

By R. G. Gürtunca

Over the past century coal miner safety and health has seen tremendous improvements, the fatality and injury rates continue to decrease while productivity continues to increase. Many of the hazards that plagued miners in the past, such as coal bumps, methane and coal dust explosions, ground fall accidents and health issues have been significantly reduced. The contribution of NIOSH research includes products for prevention and survival of mine fires, methane control measures, design procedure for underground coal mines, methods for excavation surface controls, methods and procedures for blasting, laser usage in underground mines and prevention of electrocution from overhead power lines that have reduced accidents and injuries in underground coal mines. Health research has produced products such as the personal dust monitor, noise abating technologies and ergonomic solutions for equipment operators. Research priorities at NIOSH are set by considering surveillance statistics, stakeholder inputs and loss control principles. Future research in coal mining is directed towards respiratory diseases, noise induced hearing loss, repetitive musculoskeletal injuries, traumatic injuries, falls of ground and mine disasters. The recent spate of accidents in coal mines resulted in the Miner Act of 2006 which includes a specific role for NIOSH in future mine safety research and development. The mine safety achievements in the USA reflect the commitment of industry, labour, government and research organizations to improving the safety of the mine worker.

By James Gibbs

In order to provide an initial approach to the deposits of oil shale, nahcolite, and dawsonite in the central area or the Piceance Creek Basin in northwestern Colorado, the U.S.B.M. and associated contractor personnel drilled and cased a 96-inch ID shaft to a depth of 2,371 feet. The shaft was constructed using ?big hole? drilling techniques and succeeded in giving access to previously inaccessible deposits of the above minerals. This report documents the construction from its beginning in January 1977 to its completion in January 1978. Procedures used and problems encountered are discussed in detail.

Jan 1, 1978

By B. M. Harra, O&apos

Zinc smelting is frequently termed a backward art. The term is hardly true, for great progress has been made in recent years in the design and in the thermal efficiency of the retort furnace, in the quality of retorts, in the recovery of zinc, and in the ability to treat more impure and complex ores. The fact remains, however, that the peculiar physical and chemical properties of zinc have delayed such immense advances-large smelting units, high recovery, low-unit costs, and ability to treat low-grade ores-as have been made in the metallurgy of lead and copper. In current retort-smelting practice, the ores, if carbonates, are calcined to remove carbon dioxide; or, if sulphides, are roasted to remove sulphur. The sulphur must be eliminated as completely as possible, usually to less than 1 per cent. This means that the roast must be continued for a long time at a high temperature, with resulting high cost and small capacity per furnace. The roasted ore is mixed with about 50 per cent of its weight of reducer, which may be fine coke, anthracite, or nonbituminous coal. This mixture is charged into horizontal fire-clay retorts. The retorts used in this country are about 8 inches in internal diameter by 4 feet in length and hold 50 or 60 pounds of ore. The diameter of the retort is limited by the time required for the heat to penetrate to the center of the charge; the length by the strength of the retort, which at the high temperature employed can not support the weight of the charge if the span is more than about 50 inches. The retorts are heated externally by coal, natural gas, or producer gas to a temperature of 1,200° C. or more. The zinc oxide is reduced to zinc, which is volatile at this temperature, and passes into a conical fire-clay condenser attached to one end of the retort, where it condenses to liquid zinc and is removed. Twenty-four hours are required for distillation, and because of the low heat conductivity of the retort walls and of the ore charge itself, the heat efficiency even of the most modern regenerative furnaces is only about 12 per cent. The retorts have a short life, 30 to 60 days, at the high temperature required; zinc

Jan 1, 1923

By Dennis J. Grigal

The goal of the program is to develop a dust collector system mounted on a ranging drum or arm shearer which will: 1) reduce the respirable dust level of the shearer operator by at least 75 percent; 2) be easily and economically mounted on an existing shearer; and 3) will not, through modifications to the shearer, reduce its safety or productive capability. The development program consists of three phases covering the activities of the design of the dust collector system, fabricating and installing it on the ranging arm or drum shearer, and conducting underground field tests on the modified mining machine.

Jan 1, 1980

This summary of State laws or explosives was compiled primarily to ascertain what subjects relating to their control have been acted upon by each State legislature and, in general, how they have been treated. It does not include any legislation passed after 1942, or any proclamations, regulations, or administrative orders. It does not purport or attempt to be authoritative. If any problem arises involving interpretation of the statutes of any particular State, the original source must be consulted for the exact words used by the legislature. This summary, however, will be useful In determining whether relevant statutes exist, and In locating them quickly,-with a minimum of effort. It will be of value also in comparing statutes in one State with similar statutes in other States to determine what construction has been placed upon them by the courts of those jurisdictions or to contrast the varying provisions of many States upon a similar subject. To make these comparisons easier, the statutory provisions for each State have been grouped under several major topics in outline form. Although this sometimes has resulted in disruption of the continuity of individual acts, the increased general clarity and availability of comparable sections have more than justified the procedure followed.

Jan 1, 1943

By P. L. Michael

Several evaluations were made by Modified Rhyme Test (MRT) word lists transmitted through various simulations of the Trapped-Miner Communication System being developed by the U.S. Bureau of Mines. The tests were performed in a "single blind? situation so that the evaluators would not be biased by knowing the characteristics of the system being simulated. A computer program was developed to provide a simulation of the electrical aspects of the communication system and to provide an evaluation by calculation of the articulation index (AI). The study indicates that communication through the presently proposed system will be somewhat unreliable at depths as great as 300 metre even with the system operating at maximum effeciency.

Jan 1, 1977

By John E. Conley

Of the three chemical elements most vitally essential for plant growth the United States, before World War I, had developed ample domestic supplies of but one-phosphorus. During and shortly after the war period, the fixation of nitrogen was greatly expanded in this country, as in many others, insuring a supply adequate for agriculture as well as for munitions. However, in spite of a search for sources of the third element, potassium, which began years before the war, attained almost frantic intensity between 1914 and 1919, and continued for 10 years thereafter, it was not until 1921 that the American Trona Corporation put its Searles Lake operations into continuous production. This company in 1926 became The American Potash & Chemical Co. but has never supplied much more than 15 percent of the potash consumed in the American market. Likewise, though discovered in 1921 in drill cuttings from oil wells, it was not until 1926 that domestic deposits of potassium salts adequate to render the United States independent of foreign sources of supply were proved to occur in the Permian Basin of Texas and New Mexico.

Jan 1, 1944