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By Charles L. Kimbell

In broadest overview, UN global industrial production indicators released and shown in table 2 suggest that the extractive sector of the world's mineral industry in aggregate registered a very slight upturn in 1991 relative to its 1990 performance. It also shows a continued rebound in the industry from the recessionary period of the mid-to late-1980's. These same indicators as calculated in late 1991, however, reflected a very minor downturn in extractive mineral industry operations between 1989 and 1990. This latter downturn represented a notable revision from the data reported in the immediate previous edition of this chapter, which suggested a tiny upturn. The apparent slight 1991 upturn in extractive sector industrial output generally was not mirrored in the performance of the processing sectors of the global mineral industry. Although the aggregate index for the chemicals, petroleum, coal, and rubber products manufacturers (see table 3) showed a notable gain in 1991, similar indices for nonmetallic mineral products and for base metals registered declines between 1990 and 1991. Examination of regional performance indices shows that the difficulties experienced in 1990 in maintaining output levels within the countries that formerly constituted the CMEA were reinforced by trends toward reduced gains in output levels, if not actual reductions in output, in several other areas. Generally speaking, the traditional developed market economy countries recorded downswings in overall industrial activity in 1991, particularly after midyear, whereas developing market economy countries logged gains. The developed market economy country downturns, however, were not nearly as significant as were the downturns recorded for the former centrally planned economy states - those that before 1992 were either constituent Republics within the U.S.S.R. or the latter's CMEA partners.

Jan 1, 1993

By R. E. Hall

When the criterion for control of scale prevention on the evaporating surfaces is made the conditions in the concentrated boiler water, then this control becomes an exact operation amenable to an accuracy commensurate with all other operations in the boiler room. The responsibility in boiler water conditioning, however, includes more than clean surfaces. Corrosion in feed lines, economizers and the boiler is a function of the condition of the later, and must be controlled. Steam line and turbine blading deposits must be obviated by the system of conditioning. By the chemical treatment employed, the amount and character of noncondensable uses in the steam must be controlled in accordance with the intended use of the steam. All. in all, the responsibility in boiler crater conditioning ends not with the entrance of the water into the boiler but with the passage from the boiler nozzle of steam, the dryness and rarity of which are defined by the uses to be made thereof. A clearer conception of the scope of boiler water conditioning can be obtained by reference to a diagram of the surfaces (Figure 1) at which it functions. Consideration of this diagram leads to the following outline for the problems of boiler water conditioning: (a) Prevention of scale formation on surfaces (1) In contact with water but at which no evaporation occurs. (2) At which evaporation is occurring.

Jan 1, 1926

By S. J. Page, W. R. Reed, J. A. Organiscak

NIOSH continues to conduct respirable dust control research for surface mine blasthole drilling operations. Research areas have included testing variables (shroud leakage area, drill deck cross-sectional area, shroud height, collector-to-bailing airflow ratio, etc.) that have the most impact on respirable dust control, development of a dust collector inlet hood, development of a dust collector dump point shroud, and testing of a small diameter water separating sub. This paper summarizes the results of the aforementioned research that has been completed. Additionally, past dust control research for drilling operations of both underground and surface mines completed by the U.S. Bureau of Mines, created in 1910 and incorporated into NIOSH in 1997, is reviewed.

By W. J. Wenger

Analytical, geographical, and geological data on 67 samples of crude oils from Utah are presented, along with some correlations and interpretations. Most of the, geologic formations that produce oil in other areas are also productive in Utah; and as in many other locations, the Permian, Pennsylvanian, and Mississippian formations account for the major amount of the total oil produced in the State. Some anomalies and unusual phenomena are noted. Although most Utah oils are low in sulfur, a sample containing the highest percentage of sulfur ever recorded by the Bureau of Mines is among the oils discussed in this paper. Most of the oil from the major producing formations in Utah is low in sulfur; the same formations produce high-sulfur oils in adjoining Rocky Mountain States. Some Utah oils are both waxy and asphaltic, an unusual combination of characteristics. Correlation index curves for some oils are shown suggesting compositional differences in oils from different producing formations. Production statistics trace the rapid rise of oil production in the State after the first commercial discovery in 1947 and indicate a decline in amounts produced since 1959, the year of peak production in Utah.

Jan 1, 1971

By Steven R. Davis

Dear Interested Party: Subject: Notice of Intent to Solicit Outside Opinions Regarding Amendments to the Rules Concerning the Leasing of State Owned Lands for the Mining of Metallic Minerals The Department of Natural Resources, Division of Minerals, is seeking outside opinions concerning the leasing of state owned lands far the mining of metallic minerals. Enclosed for your information in a copy of the Notice of Intent to Solicit Outside Opinions Regarding Amendments to the Rules Concerning the Leasing of State Owned Lands for the Mining of Metallic Minerals.

Jan 1, 1994

By T. M. Nasiatka

This report sterns from a study undertaken by the Federal Bureau of Mines to determine the possibility of reducing filter-cake moisture by applying radiant heat. Suitable laboratory equipment was set up to study the effect of heat, heating time, proximity of the heater to the filter cake, cake thickness, and other variables related to the final filter-cake moisture. A minus-48-mesh coal slurry and application of heat for 60 seconds resulted in filter-cake moistures 5.6 to 13.2 percentage points lower than could be accomplished by filtration alone at 24 inches of Hg for 1-1/4-and 1 1/2-inch cake thickness, respectively. The moisture reduction can be attributed to the combined effect of lower fluid viscosity and evaporation.

Jan 1, 1959

By Louis A. Panek

Tests of mine-roof models in a centrifuge show that the suspension effect due to bolting a horizontally bedded mine roof with frictionless surfaces of contact between beds depends principally on the number of bolted beds and their relative flexural rigidities, provided that sufficient bolt tension is exerted to prevent strata separations at the bolt locations. Strata separations tend to occur in the unbolted roof mainly because the beds have unequal thicknesses. "Suspension effect" refers to the transfer of part of the weight of weaker or thinner beds to the flexurally more rigid beds by roof bolts or by any other means. The factors investigated were number of beds in the bolted unit, bed thickness, modulus of elasticity of beds, length of bolts, spacing of bolts across and along the opening, bolt load, and intensity of roof load. The general principles of behavior of the bolted roof beds are explained by an approximate theory. Model test data are used to validate the theory and to obtain an expression for the "suspension efficiency". As the suspension effect actually observed in the models is smaller than that predicted by the approximate theory, the suspension efficiency in general is less than unity. Mathematical expressions are obtained for (1) the change in roof bending stress due to the suspension effect, which is needed for design of a roof-bolting system, (2) the change of roof deflection due to the suspension effect, which may be useful for evaluating the effectiveness of a roof-bolting system, and (3) the bolt load or pre-load that is required to achieve the desired reinforcing effect.

Jan 1, 1962

By George S. Rice, J. W. Paul, E. H. Denny

Data assembled by the Bureau of Mines , coupled with requests from coal companies , have emphasized the desirability of establishing standardized specifications for brattice cloth with particular respect to durability and fireproofing . Brattice cloth is a canvas or other material , often covered with some fireproofing composition , which is used extensively in coal mining for temporarily deflecting air into pillar workings and maintaining ventilation at the working faces . These specifications will be established , it is planned , through a cooperative program in which the U. S. Bureau of Standards will make a series of tests of various brattice cloths treated with respect to fire- resisting qualities and the U. S. Bureau of Mines will continue to assemble field data on the use of brattice cloth . Plans now are being made for this cooperative work. Without attempting to make a complete survey , the Bureau of Mines has made preliminary studies and investigations , and verious representative coal - mining companies have furnished detailed information . The information thus gained will be used as the basis for the cooperative investigation , but the Bureau of Mines would welcome additional information from mine operators on the character and weight of brattice cloth , conditions of use , durability , quantity employed and price . Such information should be sent to the Director , Bureau of Mines , Washington , D. C. The mine operator is interested in procuring at reasonable cost a brattice cloth with lasting fireproofing quality and of as great durability and strength as possible . There has been a lack of assembled data and knowledge regarding the subject , but the Bureau of Mines feels that this lack of knowledge may be overcome if the coal -mining companies will lend their hearty support to the cooperative investigation and submit information relative to the use of brattice cloth in their own properties . Information contained in this report is based on data obtained from coal operators in bituminous districts of Pennsylvania , Alabama , Utah , Indiana , Illinois , Colorado and Nova Scotia .

Feb 1, 1923

By Nicholas Kyriazi, John P. Shubilla

The National Institute for Occupational Safety and Health, National Personal Protective Technology Laboratory, has undertaken a study to determine how well self-contained self-rescuers (SCSRs), deployed in accordance with Federal regulations (30 CFR 75.1714), hold up in the underground environment with regard to both physical damage and aging. This report presents findings regarding laboratory-tested SCSRs in the seventh phase of testing from May 1999 to August 2000. The SCSRs were tested on human subjects and on a breathing and metabolic simulator. The results indicate that most of the apparatus, if they pass their approved inspection criteria, perform satisfactorily. The deployed CSE SR-100s, however, exhibited significantly higher inhaled carbon dioxide (CO2) levels than new units, as they did in the previous two phases. Several Draeger OXY K-Pluses that rattled when shaken were found to have potassium superoxide (KO2) particles throughout the breathing circuit, including the mouthpiece. Draeger investigated the problem and developed a shake test to detect damaged units. The durations of new Ocenco M-20s were statistically significantly longer than those of deployed units, although only by 2 min.

Jan 3, 2002

By Eliot J. White

The physical properties and clay mineral content of the major oil-producing formations in the Powder River Basin of Wyoming were determined by analyses of cores from 100 wells. Interrelationships were established among permeability, restored water saturation, clay content, and bulk swelling capacity of the crushed sample and used to estimate the susceptibility of the formations to water damage. The ratio of water permeability to gas permeability (kw/ki) offers a convenient scale for semiquantitatively estimating the water sensitivity of sands. The irreducible water saturation was also found to have a similar relationship to the clay mineral content and the water sensitivity of the sands. The average relation of water permeability to gas permeability is different for each sand, as shown by the curves, and the relative positions of the curves indicate the degree of water sensitivity of each sand from which the susceptibility to water damage may be estimated. How accurately these estimates show formation behavior under field operations will not be known until studies of field performance can be made. The water permeabilities of the Muddy, Minnelusa, and Tensleep sands average about the same as the gas permeabilities, and these sands are classified as insensitive. The water permeabilities of the Sussex and Shannon sands, at the other extreme, are much less than the gas permabilities [when average ki is 30 millidarcys (md), kw is 6.1 md], and these sands are classified as highly water sensitive. The sensitivities of the five other sands are between these extremes.

Jan 1, 1962

By John T. Kuo

The miner's seismic source strength can be approximately estimated on the basis of a single force acting in an infinite medium. Because of the uncertain- ty involved in estimating the amount of conversion from mechanical energy to seismic energy, the source strength thus estimated may be in error by as much as a half-order of magnitude. Calculations of wave transmission must take into account geometrical spreading, dissipation of energy by internal friction, and energy partition due to reflection and refraction of waves impinging on inter- faces in the layered earth. Theoretically derived peak-to-peak particle velocities in microinches per second (PIPS) are given for two models ; viz: (i) 50-feet thick and (ii) 100- feet thick 4000 ft/sec layers with Q = 20, overlying a half-space of 10,000 ft/sec material with Q = 5O;for the cases .of a hammer blow and a timber impact, at the frequencies of 50 Hz and 100 Hz. Comparison of the theoretically derived peak-to-peak particle velocity with experimental data taken at the Copper Queen Mine indicates that the theoretical particle velocity may be overestimated. A discussion of the distortion of seismic wavefronts by mine tunnels indicates that it is unfavorable to use a seismic source impact on the floor of the tunnel, since deceptive delays in arrival time are liable to occur at the surface. A program of parallel theoretical and experimental work is required to clarify uncertainties still associated with the nature and strength of the miner's seismic source signal which cannot be resolved within the approximations of this work. Its major components include theoretical investigations of the (1) Wave diffraction and scattering of an impact source on a face of a cylindrical cavity. (2) Impact of an elastic object on an elastic medium.

Jan 1, 1974

By John Henderson

If you missed this year?s Texas State Holmes Safety Association meeting, you missed a great one. On January 23 & 24, 2009, we held the meeting that was rescheduled when Hurricane Ike threatened Corpus Christi in September 2008. Sixty-five persons from across the state attended the meeting held at the Holiday Inn Emerald Beach. The weather was 82 degrees, and the sky was clear and perfect for a safety meeting. Evaluations submitted by the attendees gave the presentations, the networking, and even the food top marks. There were eight councils represented; Big Country, Central Texas, Costal Bend, Heart of Texas, Hill Country, North Texas and North Central. Presentations included Workplace Examinations, Emergency Preparedness, Screen Safety, Contractor Responsibilities, Powered Haulage, Supervising for Safety, and Basic Inspections of Slings and Rigging. Mr. Edward Lopez, SC MSHA District Manager, gave the State of the District Address.

Feb 1, 2009

Develop a simple and economical technique for determining the absolute stresses and the change of stress on the surface of roofs, floors, or walls in miners. Approach Use a commercially-available, permissible, Whittemore-type gage to determine the stress at the surface of a mine opening and to monitor any stress changes that might take place. How It Works The following equipment is used: ? One steel templet (for laying out a 60° rosette on the: rock surface). See first photograph. ? One 3/8-inch rock drill bit for drilling holes for the rosette pins. ? Six stainless-steel rosette pins. ? One Whittemore-type mechanical strain gage. ? One drill (not shown). ? Epoxy for cementing the rosette pins. ? Tape to hold the pins while the epoxy sets. The following procedure is used to determine the absolute stress on the rock surface. 1) Spot the location of the rosette pins with the templet. 2) Drill the pin holes and set the pins with epoxy cement. 3) Measure and record the distance between the pins across three diameters of the rosette with a 10-inch Whittemore-type gage. See diagram. 4) Drill a 1 1/2-inch diameter hole in the center of the

Jan 1, 1981

By D. R. Dolinar, J. Pablic, D. C. Oyler, T. P. Mucho

At a mine in central PA, high horizontal stresses have caused long running roof falls resulting in hazardous conditions for the miners and the premature abandonment of panels. Because of these conditions, the mine requested assistance of the National Institute for Occupational Safety and Health (NIOSH) in utilizing the 'advance and relieve method to mitigate the affects of horizontal stress on the mine roof. "Advance and relieve" mining involves the removal of a pillar or a portion of a pillar during development, thereby creating a cave along one side of the panel. Following cave development, the horizontal stress is relieved over the workings adjacent to the cave in the active panel. The mine has used this system in three panels with a significant reduction in stress damage and no large roof falls.

By William J. Campbell

The Federal Bureau of Mines provided five test materials--amosite, short-and long-fiber chrysotile, crocidolite, and nonfibrous tremo1ite--to the National Institute of Environmental Health Sciences (NIEHS) for studies on the biological effects of orally ingested asbestos-related materials. An inter-agency agreement between the Bureau and NIEHS made possible this program to characterize these test materials. The Bureau in turn received support through contracts with the Ontario Research Foundation for the milling of amosite and crocidolite, and with the University of Maryland for microscopic measurements. The five test materials, which were supplied in quantities of 960 to 1,200 pounds each, were characterized by chemical-instrumental analysis for elemental composition, surface area, density, X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, mineralogy, and particle size analyses. Particle size distributions were emphasized because of the current theories relating adverse biological effects to length-width characteristics of durable elongated particles.

Jan 1, 1980

By Nicholas Kyriazi

A performance comparison of 14 rescue breathing apparatus was undertaken as an assessment of past and present worldwide technology. Rescue breathing apparatus are self-contained, closed-circuit breathing apparatus used for entry into areas having atmospheres that are immediately dangerous to life and health. Apparatus tested were the Biomarine BioPak 45, 60, and 240; the Draeger BG 4 and BG-174A; the Litton LITPAC II; the MSA Custom 4500 II Air Mask, Chemox, and McCaa; the Sabre Selected Elevated Flow Apparatus (SEFA); the Scott Rescue-Pak; the Siebe Gorman Aerorlox and Proto Ten; and the SurvivairLP-120. The apparatus were tested on an automated breathing and metabolic simulator at the Pittsburgh Research Laboratory of the National Institute for Occupational Safety and Health (NIOSH). Physiological parameters monitored during the testing were average inhaled CO2 and O2, minimum inhaled CO2, inhaled wet-and dry-bulb temperatures, and peak inhalation and exhalation breathing pressures. The metabolic demand on the apparatus was 1.35 L O2/min for most of the test with two 5-min intervals of 2.5 L O2/min, the first beginning 10 min into the test and the second beginning 10 min before the end of the rated duration of the apparatus. Results presented include apparatus service life and test-averages of monitored physiological parameters. Schematic drawings and photographs of the apparatus are also included. The Draeger BG-174A and BG 4 had the highest durations—295 and 291 min, respectively. The BG 4 hadthe lowest minimum inhaled CO2 levels, attesting to the effectiveness of its CO2-absorbent canister. The SabreSEFA had the lowest average inhaled CO2 levels, due mostly to the apparently low-dead-space mask andnose cup. The MSA Air Mask, the only open-circuit device tested, had the lowest wet- and dry-bulb temperatures, with the liquid-O2-source Siebe Gorman Aerorlox having the next lowest temperatures. The only apparatus with a CO2-absorbent not in a packed-bed design, the BG-174A, had the lowest exhalation pressures. The BG 4 had the highest level of positive pressure, with the Biomarine BioPak 60, Survivair LP-120, SEFA, and Litton LITPAC II nearly as high. The BG 4 had the lowest pressure swing, with the SEFA a close second.

Jan 10, 1999

By John D. Bardill

This report covers the magnetic survey in the Redford-Clayburg area , which was part of a general survey of magnetite deposits in New York started in 1943 . Other areas being surveyed include the Star Lake district , St. Lawrence County; Russia Station district , Clinton County; Brewster district , Putnam County; and the Sterling district , Orange County. Only a relatively small portion of the area was covered by reconnaissance and detailed surveys . Results were promising enough to warrant additional work. Magnetic surveys of this type serve as a basis for selecting areas for diamond drilling by the Bureau of lines .

Jan 1, 1947

To provide coal operators with an easy-to-use stress control design procedure to minimize coal mine bumps during room-and-pillar retreat mining conducted with available continuous mining machine technology. Approach The goal of this U.S. Bureau of Mines (USBM) re¬search was to facilitate safe and efficient room-and-pillar retreat mining of bump-prone coalbeds by limiting coalbed stress adjacent to expanding gob areas through variation of section layouts. The first step was design of total-extraction pillars and their associated pillar-extraction plans. The second step was development of a coalbed strength model. The third step was development of stress limit design criteria. The fourth and final step was development of a methodology to estimate the magnitude and distribution of development and abutment loads apllied to the pillar line. The linear geometry of unlimited-width sections allowed for the accomplishment of step four with the tributary-area and linear shear-angle concepts. Increasing overburden depths required limited-width sections separated by barrier pillars to control stress within total-extraction panels. The accomplishment of step four with limited-width section designs required prediction of abutment load distributions for rectangular gobs and apportionment of these loads over mixed pillar sizes. A parametric study of the complicated interaction of various combinations of overburden depths, total-extraction panel widths, and abutment pillar widths was conducted with the USBM-developed boundary-element program MULSIM/NL.

Jan 1, 1995

By C. W. Owings

Recent recommendations of the Bureau of Mines regarding, rock dusting to prevent dust explosions in coal mines have been issued as Mine Safety Board Decision 32 and printed as Information Circular 7109.5/ The last paragraph on page 2 of I. C. 7109 states: After a mine or any part of a mine has been rock-dusted, samples of dust for analysis should be taken from the floor, ribs, roof, and timbers at such intervals of time as will give apple warning of need far redusting in order to maintain the required minimum percentage of incombustible in the mine dust. Details of the methods of sampling and analysis are given in Bureau of Mines Information Circular 7113.

Jan 1, 1940

To separate complex mineral mixtures according to their dielectric properties. Approach Develop a laboratory-scale continuous dielectric separator to separate mineral mixtures by exploiting their difference in dielectric properties. How it Works Dielectric separation is de-fined as the separation of particles based on their dielectric properties. The uniqueness of the Bureau's continuous separator, called the ?Rotating Drum Dielectric Separator,? is that it contains a high-voltage electrode con-figuration. The drum electrode consists of a series of coaxial parallel wires mounted on the outside surface of an Insulated cylinder. The screen electrode Is a wire mesh, quarter cylinder positioned outside and coaxially with the drum electrode. The drum electrode is placed in a liquid of dielectric constant K with the liquid level just above the drum's axis. The screen electrode is completely Immersed

Jan 1, 1981