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By Douglas W. Fuerstenau

A detailed experimental study of breakage kinetics in a batch rod mill indicates that while the system is inherently nonlinear, the feed disappearance kinetics for the finer sizes and the coarser sizes at high holdups is well represented by first-order behavior. The set of breakage distribution functions was found to be normalizable and independent of particle holdup in the mill. The size discretized initial breakage rate functions were found to be inversely proportional to particle holdup and almost directly proportional to particle size. A linearized grinding model that results from the first-order Taylor's series expansion of the breakage rate expression was found to give good simulations of the mill product size distributions without recourse to any parameter improvement routines. Material transport through rod mills was evaluated by investigating the effect of operating variables on the holdup and residence time distribution of particulate solids flowing through the mill. Identical experiments performed in a continuous ball mill helped delineate the fundamental differences in particulate transport through these two types of mills. Mechanistic interpretations of the observed transport phenomena are presented, and their implications in the context of tumbling mill analysis and design pointed out.

Jan 1, 1980

By B. W. Gandrud

This report presents the data of one of a series of investigations of the washability of Alabama coals as indicated by float-and-sink tests made by the Bureau of Mines at the Southern Experiment Station in cooperation with the University of Alabama and Alabama coal producers The Klondyke mine, operated by the Blocton Mining Co., is about 1 mile east of West Blocton, Bibb County, Ala., near the southwestern extremity of the Cahaba coal field. The Bureau of Mines already has published three reports that deal with the washability of Cahaba coals - one a washability study of the Clark bed at Marvel4/, one on the tabling of fine coal from the Thompson and Woodstock bed , and the third a washablility study of the Henry Ellen bed at Acmar6/.

Jan 1, 1939

By J. S. Miller

This report presents a complete coverage of results from Bureau of Mines preliminary research and the field application of explosive fracturing techniques to prepare oil shale for in situ recovery of shale oil. Small-scale surface tests were conducted to determine the feasibility of using a nitroglycerin-base explosive for creating rock fractures. Prior to underground testing, surface and near-surface tests with liquid explosives showed that explosions in sheetlike layers simulating underground fractures would propagate effectively. Successful surface experiments were conducted using layers of explosive placed between glass plates and explosive-saturated sand confined in small-diameter metal tubes. The tests in glass-plate reservoirs and metal tubes demonstrated that nitroglycerin would detonate and the explosion would propagate in cracks as thin as 1/32 inch and through distances up to 12 feet. In a shallow field test, nitroglycerin was detonated in a vertical crack in limestone and produced extensive fracturing. Explosive fracturing tests were performed in oil shale formations on seven sites near Rock Springs, Wyo. The procedures included (1) displacing and detonating nitroglycerin in natural or hydraulically induced fracture systems; (2) detonating nitroglycerin in wellbore shots; (3) displacing and detonating nitroglycerin in induced fractures followed by wellbore shots using pelletized TNT; and (4) detonating wellbore charges using pelletized TNT. The research on oil shale formations demonstrated that nitroglycerin displaced in a natural or hydraulically induced fracture would detonate, and the explosion would propagate through the explosive-filled fracture. Shooting a pattern of wells in oil shale at 100-foot depth with wellbore charges of pelletized TNT developed a satisfactory interwell fragmented zone. Tests performed on other sites at depths to 385 feet caused fragmentation of rock around the wellbore and provided interwell communication. Fourteen methods used to evaluate the extent and degree of fragmentation in the explosive fractured oil shale are discussed.

Jan 1, 1974

These proceedings consist of papers presented at two Bureau of Mines Technology Transfer Seminars for the purpose of disseminating recent advances in mining technology related to coal mine fire and explosion prevention. Primary, although not exclusive, emphasis is placed on underground coal mining. The papers address research accomplishments ranging from methods for detecting mine fires to remote sealing systems for extinguishing coal mine fires. Each paper represents the current state-of-the-art in the respective research categories. Presentations include research occurring from both Bureau in-house and contract efforts.

Jan 1, 1978

By Margaret R. Egan

A series of experiments were undertaken by the Bureau of Mines to determine the emission products of several types of conveyor belting and other combustible materials found in mines. These experiments were conducted under intermediate-scale, simulated mine conditions to determine smoke characteristics and gas concentrations. From these determinations, heat-release rates, particle sizes, obscuration rates, combustion yields, and production constants were calculated. Three types of belts were investigated: chloroprene, also known as neoprene (NP); polyvinyl chloride (PVC); and styrene-butadiene rubber (SBR). The belts were designated as ignitable or self-extinguishing depending on the length of the burning time and the subsequent combustion products. Under these experimental conditions, the SBR belts were the easiest to ignite. The PVC and NP belts tended to self- extinguish within a few minutes after ignition, but were still capable of maintaining a brief flaming period. These conveyor belt combustion results are compared with previous analyses of wood, transformer fluid, and coal fires. Together they form a data base by which findings from future experiments with other mine combustibles can be compared.

Jan 1, 1988

By M. E. Hawkins

This Bureau of Mines report provides information on all of the 329 proved salt domes in the Gulf Coastal States and offshore area of the United States. It includes specific data related to location, depth to the cap rock and to the salt, storage facilities for LPG, and production of salt, sulfur, petroleum, and rock related to or associated with the dome structure in the subject area. Also included is a brief history of the salt, sulfur, and petroleum industries as related to the salt domes. Gulf Coast salt domes were the scene of the first discovery of a large deposit of rock salt in North America, the birthplace of the Frasch sulfur industry, and the location of the first large oil gushers that ushered in the modern liquid fuel age.

Jan 1, 1966

By M. E. Hawkins

This Bureau of Mines report provides information on all of the 329 proved salt domes in the Gulf Coastal States and offshore area of the United States. It includes specific data related to location, depth to the cap rock and to the salt, storage facilities for LPG, and production of salt, sulfur, petroleum, and rock related to or associated with the dome structure in the subject area. Also included is a brief history of the salt, sulfur, and petroleum industries as related to the salt domes. Gulf Coast salt domes were the scene of the first discovery of a large deposit of rock salt in North America, the birthplace of the Frasch sulfur industry, and the location of the first large oil gushers that ushered in the modern liquid fuel age.

Jan 1, 1966

By M. G. Zabetakis, T. D. Moore

The use of a partially slotted 6.5-inch-inside-diameter vertical pipe to remove methane from a longwall gob area at a depth of 2,260 feet in the Pocahontas No. 3 coalbed ms investigated. The value of gas removed by such a pipe under free-flow conditions was found to equal the cost of the installation in this case. Approximately 25 percent of the available methane passed through the pipe without the use of an exhauster; an additional 10 percent was removed when an exhauster was employed. The diversion of methane through a vertical slotted pipe to the surface permitted the use of increased mining rates and decreased the ventilation air requirements.

Jan 1, 1972

By Sidney Katell

Covering the period from January 1961 through December 1961, this report is a continuation of the series that began with the publication of Information Circular 7516 in October 1949. It is also the third report in the series to be prepared as a cooperative effort by the Bureau of Mines and the American Association of Cost Engineers. The cooperative agreement between the two groups provides for the publication of an annual cost bibliography with the work load involved in the preparation shared equally. The abstracted articles, concerned with all facets of cost engineering in the field of chemical and petroleum plants and related facilities, came from the following sources: 1. A.A.C.E. Bulletin. 2. Bureau of Mines Information Circulars. 3. Bureau of Mines Reports of Investigation. 4. Chemical Engineering. 5. Chemical Engineering Progress. 6. Chemical Week. 7. Coal Age. 8. Coal Utilization. 9. Cost Engineering. 10. Industrial and Engineering Chemistry. 11. Nucleonics 12. Oil and Gas Journal. 13. Petroleum Engineer for Management. 14. Petroleum Refiner. 15. World Oil.

Jan 1, 1962

By Donald O. Rausch, Robert H. Merrill, David W. Wisecarver, S. Jackson Hubbard

Results are reported for stress - relief borehole - deformation measurements made in three underground openings near open - pit mines in the Ruth mining district , Nevada . A total of 134 deformation measurements were made in 8 boreholes . These measurements determined the regional stresses in the horizons above , below, and at the elevation of nearby open - pit mine floors ; knowledge of these stress conditions is considered essential information relative to certain aspects in the designing of stable pit slopes . The determinations indicate that the stresses in the district are due to the gravitational load of the overburden in a confined stress field .

Jan 1, 1964

By Leonard Obert

This report presents evidence indicating that when rock is stress-relieved during the course of mining or in drilling a core, it may be altered or damaged to the extent that the physical properties of the relieved specimen are not the same as those of the in situ rock. Furthermore, this type of damage may result from stress change other than that accompanying stress relief, such as the application of a relatively large compressive stress. In some instances the damage is microscopic, manifesting itself as incipient cracks or the failure of individual crystal bonds. However, if the sample is taken from a high-stress area, macroscopic damage may occur.

Jan 1, 1962

By Franklin D. Cooper

This Bureau of Mines report reviews in detail the foundry coke situation in the United States in 1975. It discusses intrinsic production problems and identifies opportunities for modifying operating practices so that the quality and yield of foundry coke can be enhanced without unnecessary investment in new equipment. Major topics include operating data and attendant practices and problems, the relationship of carbonization phenomena to coke quality and yield, environ- mental impacts of foundry coke plant operations, suggested research and development opportunities, and data on components of oven charges and on foundry coke production and shipments.

Jan 1, 1977

By Ronald Branstetter

Gaseous and particulate exhaust emissions from 20 diesel engines in service at five underground mines were measured with high accuracy instrumentation. The engines that were tested were checked for faults or maladjustments. The vehicle and engine maintenance organization was studied at each mine and an idealized maintenance program was devised. Faults were induced in a new diesel engine to determine their effect on the characteristics of the exhaust emissions. The results, conclusions and recommendations from this investigation are presented in this final report.

Jan 1, 1983

By G. L. Fitzpatrick

Preliminary results of an experiment in seismic holography indicate that the techniques of acoustical holography may be successfully used with seismic waves to determine the size and general shape of underground objects. This experiment was carried out under field conditions on a moderately large scale compared with the typical laboratory experiments in acoustical holography. The object to be mapped was a 100-foot-diameter, spherical, low-velocity zone of explosively fractured rock in oil shale at an average depth of 80 feet. The seismic wavelength of the Fourier component wave used in making the seismic holograms was 50 feet at a frequency of 140 cps. The hologram sampling aperture was 226 feet square and was sampled by 441 geophones in a 21 by 21 rectangular array. One novel aspect of the experiment was the use of a wide-band polychromatic explosive source of seismic waves rather than a narrow-band quasi-monochromatic vibrator source. A successful laser reconstruction of the object image from a lensless Fourier-transform hologram in the form of a 5/l6-inch-square photographic transparency is illustrated. The size of the underground object measured from the laser reconstruction of the object and the size inferred from a knowledge of the amount of explosives used to fracture the site and the tensile strength of the oil shale are found to agree.

Jan 1, 1972

By Stanley C. Rhoads

The Bureau of Mines investigated the complete ternary system K2 HfF6¬K2ZrF6-l.25 weight-percent HF at 40° C. In addition, solubility curves have been established at 25°, 30°, 500, 60°, and 70° C. These solubility data implemented a study of hafnium enrichment in feed solutions for liquid-liquid extraction processes.. Selected K2HfF6-K2 ZrF6-1.25 weight-percent HF mixtures were equilibrated in a constant temperature bath. Compositions of the equilibrated solutions and wet residues were established from combined hafnium and zirconium oxide and total fluorine analyses. All solubility curves were essentially parallel on triangular coordinates. At 40° C, the solid phase of the K2HfF6-K2ZrF6-1.25 percent HF system is a series of solid solution hydrates with K2HfF6-H20 and K2ZrF6.3H2O segments existing at the respective extremes. Since this system contains K2HfF6-H20 and K2ZrF6.3H20 segments, it is not ideal for simple separation of high-purity K2HfF6 from K2HfF6-K2ZrF6 mixtures by recrystallization. However, it would be useful for producing hafnium-enriched feed solutions from zircon concentrates for liquid-liquid extraction of hafnium from zirconium.

Jan 1, 1973

By Julian Vigil

Mountain bumps have been a problem in the coal-mining industry since the 1920's. The problem became severe in the late 40's and early 50's with the introduction of mechanized mining. Fatalities and serious injuries resulted from mountain bumps during this period. Mountain bumps again caused fatalities in the 80 's. Interviews were conducted mostly with retired coal miners having experience in bump conditions with five different coal companies. These men held positions as president, general manager, roof-control specialist, mining engineer, inspector, superintendent, mine foreman, shift foreman, section foreman, miner operator, electrician, and general laborer. Together, their comments give a good idea of the things tried to mitigate mountain bumps in the Appalachian Coal Fields.

Jan 1, 1991

By Y. H. Cheng, D. M. Lewis, V. Castranova, M. W. Barger, J. K. H. Ma, J. Y. C. Ma, W. F. Xin

Bis-basic ethers off fluorene and fluoren-9-substituted derivatives such as tilorone have been reported to inhibit silica-induced fibrosis in rats. The potential antifibrotic potency of 2,7-bis (diethylamino) ethixy fluorine fluorenone (F-9-H.H), fluorenoxime (F-9-one), and fluorenol (F-9-ol) was F-9-axime > F-9-one ~ F-9-H,H > F-9-ol. Since the release of reactive oxygen species and growth factors from alveolar macrophages (AM) in response to silica exposure has been linked to the development of pulmonary fibrosis, the present study was carried out to determine the inhibitory effects of these compounds on rat AM activity in vitro. The following parameters were monitored: (1) cellular viability; (2) zymosan-induced respiratory burst activity (superoxide and hydrogen peroxide release, chemiluminescence, and oxygen consumption) of AM; (3) drug binding to AM; and (4) lipopolysaccharide (LPS)-stimulated interleukin- I (IL-1) release from AM. The bis-basic ethers, at 40 did not affect cell viability when incubated with AM for 30 min, but significantly inhibited zymosan-induced macrophage respiratory burst activity. The inhibitory effect of these agents was F-9-oxime > F-9-one ~F-9-H,H > F-9-ol. Binding of these drugs to AM was time and dose dependent, and exhibited the following binding affinity: F-9-oxime > F-9-one > F-9-H,H > F-9-ol. F-9- oxime was shown to inhibit LPS-stimulated IL-I release by AM in a dose-dependent manner. This inhibition of IL-1 release by AM cannot be explained as a decrease in viability. In addition, these drugs were also shown to impair human fibroblast proliferation in response to serum stimuli without impairing cell viability. These results indicate a positive correlation between drug binding to AM or other cell types and their inhibitory effects on cellular activities including oxygen consumption, superoxide release, hydrogen peroxide secretion, chemiluminescence, IL-I release, and proliferation. The ability of-these bis-basic ethers to modify AM and fibroblast functions in vitro suggests that further investigation of their reported antifibrotic potency in vivo is warranted.

Dec 1, 1996

By W. G. Pariseau

This Bureau of Mines report is an evaluation of the state of knowledge about gravity flow from bin hoppers, the most commonly used method of handling bulk materials where the force of gravity is used. The requirements for flow to be initiated and to continue, formulas developed experimentally or mathematically from various assumptions to describe the materials flow, and the question of whether or not a material will flow over the entire cross sectional area of the bin hopper according to the flow regime developed are the primary areas discussed. The work of A. W. Jenike, whose pioneering investigations raised bin hop- per design from the trial and error state, is examined in depth and its limitations and assumptions are pointed out. Bin hopper design depends heavily upon prior experience, and suggestions for further studies of bin hopper flow to include the effects of feeders are made.

Jan 1, 1972

By William A. Beck

This report describes the loading and transportation practices employed at the zinc-lead mines of The Eagle-Picher Co., Jo Daviess County, Ill., and Lafayette County, Wis. The report also gives a brief history of the Illinois-Wisconsin zinc-lead district and the operations of the company in the area. The diesel-powered, rubber-tired loading and haulage equipment is described and illustrated from the operational point of view only, and an analysis is made of the materials-handling system without going into health and safety factors. The costs per ton of the various components of mechanical loading, underground haulage, underground crushing, and hoisting for fiscal year 1960 are tabulated.

Jan 1, 1964

By B. R. Klahold

Each year hundreds of mineral specimens and numerous inquiries regarding tests and analyses of minerals and related inorganic substances are received by the Bureau of Mines. In response to this demand, in years past Information Circulars were published containing a list of laboratories. This paper is a revised version of Information Circular 7523, The listing has been changed from a regional basis to one of States arranged alphabetically and grouped by cities, again alphabetically, with Alaska and Canada listed at the end. All the services given at these laboratories are listed on one page for convenience and brevity. This list is compiled as a public service, and none of the laboratories listed herein are recommended over any other nor can the Bureau of Mines vouch for their results.

Jan 1, 1954