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By Lewis V. Wade

This Bureau of Mines work was performed to theoretically determine the effects of specimen radius and specimen boundary conditions on the stress state in the rock near the anchor for rock specimens used to investigate expansion anchor behavior. Finite element analyses were performed on mathematical models of varying radius and boundary conditions. A review of the results of these analyses revealed a definite convergence of all stress measures considered as the specimen radius increased. There was, however, a significant variation in all stress measures as the specimen diameter increased from 8 to 12 inches.

Jan 1, 1973

By T. W. Hunter

THE TOTAL production of energy in the United States in 1954 decreased 4.6 percent below 1953. The production of coal continued to decline, and the production of crude oil decreased for the first time since 1949. These decreases were partly offset by an increase in the production of natural gas. The total energy production of 35,365 trillion B. t. u. in 1954 was the lowest since 1950. [ ] This drop in energy production was consistent with the 1.1-percent decline in gross national product during the year-from 364.5 billion dollars in 1953 to 360.5 billion in 1954.

Jan 1, 1958

By Kathleen J. D?Amico

This summary appears in Minerals Year- book volumes I-II, and III, which cover mineral production in the United States, its island possessions, the Canal Zone, and the Commonwealth of Puerto Rico, as well as the principal minerals imported into and exported from the United States. The sections of this chapter and the area chapters in volume III contain further details on production. A summary table comparing world and U.S. mineral production also is included. Mineral production may be measured at any of several stages of extraction and processing. The stage of measurement used in the chapter is normally what is termed "mine output." It usually refers to minerals in the form in which they are first extracted from the ground, but customarily includes for some minerals the product of auxiliary processing operations at or near mines.

Jan 1, 1970

Because surface mining removes the original plant cover from the land and exposes the soil, special care is needed. Until the mined land is stabilized by revegetation, snowmelt and rainfall can pick up sediment and erode mined lands much faster than undisturbed areas. Sediment control is an important aspect of protecting the environment during mining and reclamation because without it, large amounts of sediment can clog streams, increase the risk of flooding, damage irrigation systems, harm aquatic habitat, and limit the use of water for other purposes. Stream quality can be affected many miles downstream from the mine. Before SMCRA was implemented many streams were degraded by uncontrolled sediment from mining. Sediment is controlled through careful planning and a design that incorporates a variety of measures that work together to reduce soil erosion at the mine. Disturbed areas are graded, and some areas terraced, to achieve stable slopes, reduce runoff water velocity, increase infiltration, and divert runoff into drainage channels so that it flows away from unvegetated, erodible areas. Grading along the slope contour and scarify in gun vegetated slopes with bulldozer track marks help prevent erosion by slowing down the flow of water. Runoff from haul roads is controlled by culverts and roadside ditches. Sedimentation ponds or other forms of sediment control are required at all mines to minimize the amount of sediment leaving the site.

Jan 1, 1992

By D. R. Tesarik

An instrumentation and numeric modeling study was conducted by the Bureau of Mines at the Magmont Mine in Bixby, MO. An isolated section of this room-and-pillar mine was monitored with borehole and closure extensometers during a pillar recovery program to determine stress redistribution. In situ stress measurements were taken in the rib before pillar extraction began. Sample cores from the boreholes were taken for analysis of the properties of the host rock in the laboratory. The extensometers recorded no measurable displacements during most of the operation. Two-dimensional, finite-element; three-dimensional, finite-element; and three-dimensional displace-ment discontinuity codes were used to model the area of study. The finite-element models were run with two initial stress conditions, i.e., stress due to gravity only and stress obtained by in situ measurements. Horizontal stresses in the models reduced the calculated factor-of-safety in the mine back by up to a factor of 10, but did not have a significant effect on calculated pillar stability.

Jan 1, 1989

By John C. Holtz

The Bureau of Mines studied air contamination caused by diesel exhaust in a 10,000-ft ventilated tunnel. Sequential air samples were taken at the ends and middle of the tunnel during an operating cycle. Observed and calculated results for carbon dioxide, carbon monoxide, and nitrogen oxides were essentially in agreement. Nitrogen dioxide was present only in trace amounts. It was found that contamination was related to the volume of ventilating air, the number of haulage trips, train speed, and engine load.

Jan 1, 1968

By R. S. Olsen

The Bureau of Mines is engaged in a continuing research effort toward the recovery of alumina from kaolinitic clay and other nonbauxitic domestic minerals. Hydrochloric acid extraction of calcined clay is among the acid processes under consideration. Although aluminum is easily leached from calcined clay, the presence of fines and slimes in the leached residue has hindered the application of this and other acid leaching processes. A clay feed preparation method was therefore developed that eliminated the slimy nature and the separation problems normally associated with leached clay residues. The preparation process consists of crushing the raw clay to minus 20 mesh, dampening the crushed clay with a fine water mist while tumbling on a rotating disk, and calcining the misted clay at 750° C. The misting process increases residue settling rates threefold to 9 cm/min (18 ft/hr) and filtration rates by two orders of magnitude. Leaching-kinetics were determined for misted clay feeds in a batch, stirred-tank reactor. Rapid leaching occurred during the first 85 to 90 pct of the extraction. The linear relationship of extraction to time during this initial phase corresponded to a zero order reaction with a rate constant of around 10 pct/min.

Jan 1, 1981

By M. MacLaughlin, J. Whyatt

A case study is presented that relates statistical descriptions of joint sets to the distribution of local wedge failures along the crest of a catch bench at the Yellowstone Talc Mine. The fracture sets and bench width were mapped by teams of geological engineering students from Montana Tech under the direction of Dr. Mary MacLaughlin. The students analyzed the fracture data, conducted physical property tests, and used a beta version of a NIOSH program “Bwedge” to predict the distribution of surviving bench widths. In the course of this analysis the students developed evidence of software performance issues that, unfortunately, frustrated their analysis. These have now been addressed and a full analysis completed. The analysis confirms the validity of the student mapping program and provides insight into the effects of blasting and excavation practices on the bench. It also provides a tool for exploring the pattern of bench crest failure that would result from variations in both bench geometry and blasting practices.

By L. E. Schultze

The Bureau of Mines operated a mineral recovery unit to recover metal values from post-flash geothermal brines from the Salton Sea known geothermal resource area as part of its research into the use of plentiful resources. The brine was available for metals recovery after its heat content had been used to generate electricity. The brine source was treated with lime to precipitate the contained iron, manganese, lead, and zinc before injection of the heat-depleted brine into the underground reservoir. Data are presented on the effects of process variables, such as rate and method of lime addition and air oxidation versus air exclusion. Variations in precipitation of metal values, composition of precipitates, effectiveness of slurry thickeners, and methods of treating the precipitates to recover metal values are discussed.

Jan 1, 1982

By Peter F. Steidl

As part of the Bureau of Mines methane control program, the Upper Free- port coalbed was studied in Fayette County, Pa., where this coalbed lies about 650 feet below the Pittsburgh coalbed and contains the largest remaining reserves of any coalbed in the county. Coal and overburden isopachs, structure and joint pattern maps, and a fence diagram were prepared using data from gas and oil exploration logs and coal outcrops. These maps will aid in determining the need and/or feasibility of degasifying the Upper Freeport coalbed in the study area. Much of the coalbed in this area is under 600 to 1,400 feet of overburden. By correlation with data from the Pittsburgh coalbed, the gas content at depths of this order is estimated to be between 140 to 300 cf/ton of coal, for a total of 190 to 400 billion cubic feet of methane in this coalbed in Fayette County.

Jan 1, 1977

By W. H. Lewis

This Bureau of Mines report and its companion report (Information Circular 9074) have been prepared as a complete reference on underground coal mine lighting. This report discusses the fundamentals of light and its interrelationship with the visual process. The purpose of the report is to insure an understanding of the numerous complex and interrelated factors that must be considered to design and implement a mine lighting system that will satisfy human needs for good vision and comfort. Topics include history, objectives, and technical considerations of coal mine lighting; light physics; light and vision relationships; and disability and discomfort glare.

Jan 1, 1986

By R. Van A. Mills

[In previous contributions** the writer has called attention to important relations that faulting bears to the migration and accumulation of oil end gas. It has been pointed that favorably situated parts of oil and gas bearing, sands have been enriched by migration art segregation incident to faulting. The escape of water through natural passages such. as fault fissures has induced wide spread hydraulic currents through the beds toward these, points, of diminished pressure and these water currents, plus buoyancy hove contributed largely toward the migration of oil to favorable rock entrapments in the vicinity of the faults.*** The propulsive force of expanding gas has been one of the contributing causes for the hydraulic currents. Paradoxical as it may seem, the escape of gas with entrained oil through fissures has been on important factor In the migration, and accumulation of oil in many faulted areas. Compressed gas is the propulsive force by which oil generally moves to producing wells. It is also one of the propulsive forces by which oil has moved with or even ahead of water under conditions: of differential pressure brought about by faulting.]

Jan 1, 1922

By Sarah P. Guerrino

This chapter summarizes data on crude nonfuel mineral production for the United States, its island possessions, and the Commonwealth of Puerto Rico. Included also are the tables that show the principal nonfuel mineral commodities exported from and imported into the United States and that compare world and U.S. mineral production. The detailed data from which these tables were derived are contained in the individual commodity chapters of Volume I and in the State chapters of Volume II of this edition of the Minerals Yearbook. Although crude mineral production may be measured at any of several stages of extraction and processing, the stage of measurement used in this chapter is what is normally termed ?mine output.? It usually refers to minerals or ores in the form in which they are first extracted from the ground, but customarily includes the output from auxiliary processing at or near the mines.

Jan 1, 1987

By G. S. Scott, G. W. Jones

"INTRODUCTION In the course of the investigation the Bureau of Mines is carrying on to determine the causes, behavior, a. control of mine fires, the detection of incipient heating underground in the mines and above ground in refuse banks has received consideration.Many of the anthracite fires have been active for years and have progressed considerable distances free their original source.Some of the fires are in inaccessible territory, and it is often impossible to determine with any degree of accuracy their exact location or even the veins of coal that are afire, especially when the fire is in the upper strata and when it is impossible to go underground because of flooded conditions or the presence of an irrespirable atmosphere.In such cases, the only means by which the trend of a fire may be ascertained (as a result of any fire-fighting methods that may have been employed) are the sampling, exanination, and interpretation of the gaseous products coming from the fire area. The most important information desired is to know whether the temperature in the heated area is increasing or decreasing and to determine whether a fire that has been sealed is cooling down to normal mine temperatures or is maintaining its heat or is increasing in intensity due to infiltration of outside air.Interpretation of the analyses of gaseous products from refuse banks on the surface also should be of value in combating such fires. Refuse bank fires, with the additional danger of starting an underground fire through ignition of the outcrop, are by no means unknown in the anthracite coal region, and the causes of such fires are not always apparent. In a few cases the causes have been strongly suggestive of spontaneous origin."

Jun 1, 1938

By C. H. Elder, M. C. Irani

Two degasification test boreholes were drilled to depths of 1,238 and 1,212 feet on Bureau of Mines property at Bruceton, Pa., as part of the Bureau's long-range coal degasification program. The holes provided detailed geologic information and geologic sections, which were correlated with regional stratigraphic cross sections prepared by the Pennsylvania Geological Survey. Gas content determinations and coal analyses were made on the Upper Freeport, Middle Kittanning, Clarion, Brookville, and Mercer coalbeds; gas content of the coalbeds ranged from 53 to 165 cubic feet per ton. Formation pressure and gas flow tests were conducted on selected coalbed intervals in borehole 1; formation pressures ranged from 292 to 473 psig. The middle Kittanning coalbed was hydraulically stimulated using very heavy gelled water, but gas production remained low because gel residue and formation water inhibited the flow of gas. Gas contents in the Clarion, Upper Brookville, and Mercer coalbeds were anomalously low owing to the proximity of porous sand- stones which act as reservoirs for gas migrating from coalbeds.

Jan 1, 1977

By L. C. IlsLey

"The underlying principle of the storage battery was discovered within the memory of many still living, hence storage-battery locomotives, which were made possible by this discovery, represent a still more recent development. The Journal of the Franklin Institute for December, 1883, gives an account of the building of an electrical omnibus by The Electrical Storage Battery Co., of Millwall, London, This, if not the first, was among the first attempts to, use the storage battery as the source of energy for locomotion.During the period 1888 to 1893 occasional attempts were made to apply this idea practically, but not much was achieved along useful lines.. The progress during the next, 15 years was slow, and little success was achieved. Therefore, the last two decades may be considered the successful development period of the storage-battery locomotive.In coal mining, the application of the storage-battery locomotive is chiefly in gathering service in competition with animal or cable-reel locomotives. The locomotive delivers empty cars to the rooms or working places where the coal is being mined and hauls the loaded cars from the rooms. The length of haul depends upon the distance of, the junction point from the active workings of the mine. As a rule the haulage from the junction point to the foot of the shaft or bottom of the slope is done by trolley locomotives, but in some instances where the grades permit this main-line haulage work it: performed by storage-battery locomotives.As the place storage-battery locomotives occupy with respect to safe haulage in gassy mines appears to be misunderstood, it is the purpose of this paper to clarify this point.Those who originally designed storage-battery locomotives had no thought of safety in mind and it is just as well that they did not, as these early types of storage-battery locomotives with open controller open motor, open rheostats, flimsy headlights, and crude wiring were very dangerous electrically and not at' all suitable for use in a gassy mine. These locomotives, however, were placed in mines in which open lights were permitted and they replaced considerable animal haulage. Later they were gradually introduced in mines where closed lights were used, but in most cases these mines were not extremely gassy."

May 1, 1928

By C. L. Karr

The U.S. Bureau of Mines is currently investigating the use of genetic algorithms (GA's) for solving optimization problems. This computer search technique, based on the mechanics of natural genetics, was used to perform simple least squares curve fitting. Three examples are presented in which a GA manipulates binary coded strings to produce near-optimal solutions to least squares curve-fitting problems after having viewed only a small portion of the search space. The examples include fitting data to the equation of a line, the equation of a parabola, and the Ree-Eyring equation.

Jan 1, 1991

By Nicholas P. Kripakov

The U.S. Bureau of Mines examined the applicability of existing material models to solve practical geotechnical mining-related problems by solving a yielding pillar stability problem considering confining effects on strength. Numerical difficulties normally encountered with modeling strain softening behavior were eased with a simplified computational procedure using a quasi-elastic approach to account for residual strength after initial failure. Although in agreement with a confined-core pillar design method using actual mine conditions that include mine layout geometry, overburden geology, and rock properties of the deposit and surrounding structure, the results cannot be verified because measured field data are not available at this writing.

Jan 1, 1981

By C. H. Schwartz

A thermal radiation probe was constructed and tested in pulverized-coal-fired furnaces. A rotatable sensing head on the side of a water-cooled probe permitted measurement of radiant flux within a 7.20 cone from any desired direction to a point within a furnace. A response curve for a corner-fired furnace showed radiant flux of 130,000 Btu per sq ft per hr, when viewing flame, and 60,000 Btu per sq ft per hr, when sensing wall reflection. Detailed drawings and fabrication procedure are given.

Jan 1, 1970

By Yael Miron

ANFO blasting agents may undergo an exothermic reaction when they contact warm ore bodies that contain pyrite and its weathering products. The reaction is very fast at temperatures above 80° C. Urea, when present in sufficient amounts, inhibits this reaction at temperatures below 180° C. But urea-ammonium nitrate mixtures are very hygroscopic and, in certain climates, may be difficult to handle in the field. Reaction-inhibiting characteristics of three compounds were reported by the Bureau of Mines in 1979. Recently, the Bureau investigated the reaction-inhibiting qualities of five additional compounds. Mixtures of ANFO, pyrite, weathering product, and prospective inhibitors were slowly heated, under conditions simulating a hot borehole, to determine prospective inhibitor capability at temperatures up to ~175° C. Small-scale thermal tests of the same mixtures were used for verification and clarification of results. Two organic compounds, phthalimide and xanthine, similar in structure to urea, failed to inhibit the reaction. Zinc oxide and calcium carbonate were found inferior to urea, though zinc oxide raised the onset of reaction from 80° C to about 140° C. Only magnesium oxide was found to be similar to urea in its inhibitory ability at temperatures below 175° C. Based on results from analysis of quenched residues, the use of more than 5 wt-pct magnesium oxide is recommended.

Jan 1, 1982