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By William A. Hustrulid

A technical and economic evaluation of the potential for improving mining productivity through the use of underreamers in blastholes, specifically in relation to Minnesota taconite, Arizona surface copper and in situ mining operations is presented. Included are (1) a review of the drilling and blasting practices presently being used, (2) a discussion of current underreamer technology. (3) the presentation of a general economic cost model for underreaming, (4) the application of the model to surface taconite, surface copper and in situ mining, and (5) a summary discussion including required performance specifications, potential overall benefits, and recommendations for further development.

Jan 1, 1977

By A. Renton Amell

The rate of dissolution of U02 was measured in acid solutions similar to those used for in situ leaching, with S04 of 10-1.82 to 10-4 M, Fe(III) of 10-2 to 10-4 M and pH's of 1.1 to 2.3. The dependence of dissolution rate on pH was small and inconsistent, probably reflecting the combined effects of a very weakly polar oxidizing complex, probably FeSO4+, and a nearly neutral U02 surface. Differences in the state of the U02 surface may explain this variability as well as contrasts between these results and results reported in other work. Changing either S04 or Fe(III) concentrations significantly affects dissolution rates. Increasing low sulfate concentrations in solutions containing 10 2 M Fe(III) at pH 2 results in formation of FeSO4+. In such solutions, rates increased with (S04)/(Fe(III)) up to 1:30, thereby indicating that the oxidation of U02 by FeSO4 is more rapid than by Fe3+. However, the dissolution rate decreased at higher (SO4)/ (Fe(III)), due either to sorption of SO42- on the UO2 surface or to formation of other less reactive sulfate complexes such as Fe(S04)2 or FeHSO4+ However, Fe(III) concentration is the dominant factor in determining solution rates. The rate was directly proportional to ferric iron concentration, indicating that the rate-determining step of the dissolution reaction is a single-electron oxidation by a ferric complex. Dissolution rates were lower in solutions of 0.1 and 1.0% H202 (0.029 and 0.29 M) than at similar concentrations of ferric iron because of formation of an insoluble surface coating of uranium peroxide, UO4?4H20. This phase may limit the value of hydrogen peroxide as an oxidant in lixiviants, not only by its very low solubility, but perhaps also by filling pores and reducing permeability in the ore body.

Jan 1, 1978

By Dale R. Spangenberg

This Bureau of Mines Information Circular on phosphate is one of a series of minerals availability commodity directories. Nonconfidential information from the Minerals Availability Program data base covering 148 domestic and 103 foreign phosphate properties and deposits has been abstracted for use in this directory. Abstracts include applicable data on location, published reserves and resources, geology, mine and beneficiation systems, and operational information.

Jan 1, 1983

By Harold E. Marr

The computer program XRF4 was designed by the Bureau of Mines to provide for the calculation of several different interelement correction procedures in X-ray fluorescence analysis, including Lachance-Traill, Rasberry-Heinrich, and Claisse-Quintin procedures. The program was written in the BASIC language for timesharing application, and a conversational interaction with the computer is employed during operation. This report presents test problems using data for iron-nickel-chromium alloys and aluminum alloys and directions for use of the program.

Jan 1, 1976

By Eliezer Kamon

To finalize the three years granted for the study of miners physiological responses to emergency situations, all the data obtained, were summarized into the following relevant sections; A.. Information on elements of the Man Test required under Subpart 4, Part 2, Title 30 in the Code of Federal Regulation (see Table M-T and Ref. I., Section A). B. Investigation on possible emergency activities, its simulation in the laboratory and the physiologic data obtained on miners performing them This included some studies under cool ambient conditions, expected to prevail in coal mines. C. While in section B the steady state responses have been obtained, time was devoted to establish a unit that will allow data gathering for non-steady state, i.e., transient responses to rapidly changing activities. Section B and C contained elements that were relevant to section A; the Man Test. Therefore some of the information described under section A Man Test, were actually measured during the battery of tests in either section B or in section C.

Jan 1, 1974

By E. G. Davis

A research program to evaluate the use of ceramic die inserts for ferrous diecasting was initiated by the Bureau of Mines at its Tuscaloosa Research Center. Data were compiled from the literature to characterize selected ceramic materials with respect to thermal properties, thermal-shock resistance factors, chemical reactions with molten metals, and processes required to form die components. With this information and a computer model developed for predicting temperature and stress patterns induced in ceramic materials during simulated ferrous diecasting operations, 27 candidate materials were evaluated. After evaluation, only 15 were considered for testing in an apparatus constructed to immerse the ceramic specimens in molten cast iron. Of these, 13 were tested in a modified testing unit in which cast iron was poured onto the specimens. These tests resulted in the selection of three materials for further testing: boron carbonitride (50 pct B4C:5O pct BN), boron nitride-grade M (BN-M, 40 pct BN, 60 pct Si02), and pyrolytic boron nitride (PBN). Tests in a gravity-flow die unit showed that PBN was thermal-shock resistant and could be used in diecasting of ferrous metals.

Jan 1, 1981

By W. H. Strickland, R. H. King

Ultrasonic ranging sensors are inexpensive, have no moving parts, have no lenses to clean, are normally small and unobtrusive, and can measure distances through moderate amounts of dust, smoke, and humidity, so they are well suited to underground mines. In the work reported here, conducted by the U.S. Bureau of Mines, researchers tested ultrasonic ranging sensors for their abiity to define rib line features for computer-aided navigation of underground mine mobile equipment. The investigation began with laboratory tests of field of view, angle of incidence, intersensor variation, and ranging accuracy of the individual rangers in a ring array produced by Denning Robotics of Wilmington, MA. The results showed that the sensors have good accuracy and low variability. Additional experiments at AMAX's Henderson Mine showed the sensors could accurately and reliably measure the distance to mine features, including convex and concave corners and rib intersections. The results showed that when used properly, the ranger data are accurate enough for reliable mine vehicle navigation When used incorrectly, ultrasonic rangers do not provide the anticipated data. Therefore, this report explains the principles of ultrasonic range measurement, describes the ranger's strengths and weaknesses, and explains proper ranger use and data analysis.

Jan 1, 1993

By S. Raghavan

An investigation of the possibility of improving the grinding characteristics of a gabbro ore containing copper and nickel sulfides via a thermal shock treatment technique has been carried out. The results obtained indicate that the breakage characteristics of the gabbro are particles can be significantly improved by preheating the are particles to a temperature around 400°C followed by rapid water quenching. For a given power input and feed size, the thermally treated material produces a product of much finer distribution than the untreated material. An assessment of the improvement in grindability has been made by calculating feed size selection functions for untreated and heat-treated materials.

Jan 1, 1981

By M. W. Von Bernewitz

Because the cutting and polishing of stones are parts of the work of the Bureau of Mines in its study of rocks and minerals and in the determination of specimens sent in for identification, it was decided that a circular covering the subject in a general way would be of practical interest. As several books and periodicals give details of the problems in cutting and polishing, this report will not duplicate their information more than necessary. ACKNOWLEDGMENT The manuscript for this circular was read by Oliver Bowles and Forrest Moyer, Building Materials unit, Bureau of Mines, who supplied some of the illustrations; several photographs were taken by Howard Carl, Optical Section, Bureau of Mines. Equipment firms that y contributed information and publishing houses whose books have been abstracted are mentioned in the text.

Jan 1, 1940

By Compiled by Staff

"INTRODUCTIONThe U.S. Bureau of Mines (USBM) was established in the public interest to conclude inquiries and scientific and technologic investigations on mining and the preparation, treatment, and utilization of mineral substances; to promote health and safety in the mineral industries; to conserve material resources and prevent their waste; to further economic development; to increaseee efficiency in the mining, metallurgical, quarrying, and other mineral industries; and to inquire into the economic conditions affecting those industries. The organic act of the Bureau, as amended by Congress and approved February 25, 1913, made it the province and duty of the U.S. Bureau of Mines to ""disseminate information concerning these subjects in such manner as will best carry out the purposes of this Act.""In accordance with this directive, USBM reports the findings of its research and investigations in its own series of publications and also in articles that: appear in scientific, technical, and trade journals; in "" proceedings of conventions and seminars; in' reference books; and in other non-USBM publications. The number of these reports, the wide range of subjects they cover, and the variety of mediums in which they appear make this kind of list both necessary and valuable.This edition describes reports and articles published during calendar years 1992 and 1993. It supplements the 50-year list of Bureau publications from July 1, 1910, to January 1, 196O 2; and these 5- year lists of publications and articles: from January 1, 1965, to December 31, 1969 4, from January 1, 1970,to December 31, 19745 , from January 1, 1975, to December 31, 1979 6 , from January 1, 1980, to December 31, 1984 7 , and from January 1, 1985, to December 31, 1989 8."

Jan 1, 1994

By Fred N. Kissell

This handbook describes effective methods for the control of methane gas in mines and tunnels. It assumes the reader is familiar with mining. The first chapter covers facts about methane important to mine safety, such as the explosibility of gas mixtures. The second chapter covers methane sampling, which is crucial because many methane explosions have been attributed to sampling deficiencies. Subsequent chapters describe methane control methods for different kinds of mines and mining equipment, primarily for U.S. coal mines. These coal mine chapters include continuous miners and longwalls, including bleeders. Coal seam degasification is covered extensively. Other coal mine chapters deal with methane emission forecasting and predicting the excess gas from troublesome geologic features like faults. Additional coal chapters contain methane controls for shaft sinking and shaft filling, for surface highwall mines, and for coal storage silos. Major coal mine explosion disasters have always involved the combustion of coal dust, originally triggered by methane. Thus, a chapter is included on making coal dust inert so it cannot explode. Methane is surprisingly common in metal and nonmetal mines around the world, as well as in many tunnels as they are excavated. Accordingly, a chapter is included on metal and nonmetal mines and another on tunnels. Proper ventilation plays the major role in keeping mines free of hazardous methane accumulations. The ventilation discussed in this handbook, except for the chapter on bleeder systems, deals only with so-called face ventilation, i.e., ventilation of the immediate working face area, not ventilation of the mine as a whole. The omission of whole-mine ventilation was necessary to keep this handbook to a reasonable size and because a huge amount of excellent information is available on the subject.2

Jan 1, 2006

By Robert F. Chaiken

An absorption-desorption model of particle reactivity was employed to describe the observed relationship between two apparently diverse phenomena which have been the subject of considerable study at the U.S. Bureau of Mines: (1) coal-rock dust reflectance and (2) coal-rock dust explosibility. The model accounts for heterogeneities in particle-size and material properties; however, in the present report, only particle-size distribution is considered. A mean particle-size parameter, appropriate to the explosion extinction process, is derived, and then taken as appropriate to describing optical reflectance. The derived form-to-function relationships for the two processes, when compared with experimental data, suggest that a problem exists with previously derived theory relating optical reflectance to rock dust concentration. A reexamination of that theory leads to a new theoretical expression, changed by a factor of 2, for the variation of rock dust concentration with reflectance which is in quite good agreement with experimental results. The current work offers justification for measuring and establishing rock dust requirements for specific coal dust size distribution(s) found in the mine-distributions that undoubtedly depend on the mining method and the type of coalbed.

Jan 1, 2010

By Margaret R. Egan

A study of the combustion emission products of rigid ventilation ducting was completed by the U.S. Bureau of Mines. The ducting was composed of fiberglass-reinforced polyester resin. Four properties of the ducting were evaluated: (1) propensity to ignite, (2) smoke characteristics, (3) gas emissions, and (4) heat release. Particle sizes, obscuration, optical densities, and production constants for gas and smoke were also calculated. These results provide comprehensive data about the emission products, detectability, and relative hazards of fiberglass-reinforced plastic ducting and other mine combustibles under realistic fire conditions.

Jan 1, 1990

By John W. Colburn

A tractor-integrated version of an explosive ripping system was developed for mining application. This system utilizes diesel fuel and a tractor-mounted blower supplying 30 psig compressed air to a two-stage combustion chamber to produce a high pressure (600 psia) gas charge. The charge is rapidly released into the rock formation near the tip of the ripper. The system, mounted on a D9 tractor, was tested at several quarry and mining operations to investigate rock fracturing effectiveness. Although the results of comparative ripping passes conclusively demonstrated that the system increases rock fracture, performance of the system is strongly dependent on rock morphology and properties as well as basic performance of the tractor-ripper. The theory of conventional and explosive ripping modes is described and existing correlations of seismic velocity and ripper performance are shown to be in error.

Jan 1, 1977

By K. L. Paciorek

The aim of this program was to develop a reliable and meaning-ful basts for assessing certain safety aspects, namely fire and, in particular, toxicity hazards of articles employed in underground coal mining operations. This investigation was centered on the thermal oxidative degradation of "pure" ingredients used specifically in the formulation of conveyor beltings. To achieve this goal all products formed on thermal oxidative degradation of the materials studied were analyzed, identified I and the amount of each individual species present was determined quantitatively on a weight of product per weight of material basis. The weight/weight data thus obtained can then be factorized to reflect the relative toxicity of each individual species present, using for example the Threshold Limit Values adopted by the American Conference of Governmental and Industrial Hygienists, whereby an overall "toxicity index" can be arrived at which makes it possible to compare the different potential formulation components in a quantitative manner insofar as their "toxicity" is concerned. Furthermore, knowing the off-gassing characteristics of the commonly used additives I their contribution to the product mix obtained from actual belting can be postulated. Conversely, from the species obtained on thermal oxidative degradation of conveyor belts the type and to a degree the content of additives can be deduced. Based on the se data meaningful regulations governing the material selection for underground use can be developed. For these studies a quiescent system at 370°C was employed. Thermogravimetric and differential thermal analyses were performed to supplement and extend the sealed system investigations and to provide information regarding thermal oxidative behavior under dynamic conditions.

Jan 1, 1975

By Glenn Adkins

This report characterizes pivoting joints in the structures of mining machinery and how the wear on the various components, i.e., pins, lugs, yokes and bushings, may affect the safety of mine personnel where these components are allowed to wear excessively before repair or replacement.

Jan 1, 1979

By Steven W. Schmauch

In 1986, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines Studied 25,340 acres of the 28,960-acre Twelve Mile Creek Wilderness Study Area (OR-003-162) in order to evaluate its identified mineral resources. The study area is located in Malheur County, OR, about 30 miles northwest of McDermitt, NV. The area is underlain by thick sequences of rhyolite to with lesser amounts of andesite and basalt flows. Bureau of Mines personnel reviewed pertinent literature, mining records, and examined the study area for possible mineral resources in geologically favorable sites. There are no organized mining districts and no record of past or current mining activity. Based on sample results, published literature and field observations, there are no identified mineral resources.

Jan 1, 1987

"To prevent the propagation of mine explosions, the Bureau of Mines recommends:1. That all coal and lignite mines, except anthracite mines shall be rock dusted.2. That rock dust shall be distributed upon top, bottom, and sides of all underground openings of every description, to within. at least 4o feet of all working faces and the areas not rock dusted shall be kept wet.3. That the rock dust shall be maintained in, such quantity that the incombustible material in representative samples of dust collected shall not be less than 65 percent. Where methane gas is present in the ventilating current, the minimum percentage of incombustible matter in the mine dust shall be increased 1 percent for each 0.1 percent of methane.4. That when the rock dust in any area becomes caked so thatit cannot be dispersed readily as a cloud in the air, that part of the mine shall be redusted immediately.5. That the dust to be used shall not contain more than 5 percent of combustible matter nor. more than 25 percent of quartz or free silica; all of the dust shall pass through a sieve having 20 meshes per linear inch and 60 percent or more shall pass through a sieve having 200 meshes per linear inch; the dust shall not absorb moisture from the air to such an extent as to cake and destroy its effectiveness as a dry dust.6. That rock-dust barriers shall not be regarded as a substitute for generalized rock dusting.Research and experience have shown that maintenance of an adequate percentage of rock dust in all underground openings, whether gassy or not, of bituminous and subbituminous coal and lignite mines (anthracite dust does not propagate explosions) is the best means of preventing coal dust explosions. In rare instances where all fine coal particles on the floor, ribs, roof, and timbers are in a muddy condition continuously rock dusting is unnecessary.The term ""underground openings"" refers to all unsealed openings whether they contain track or not, and includes rooms, entries, crosscuts, breakthroughs, rock tunnels, slopes, haulageways, airways, and travelingways. The sealing of unused or abandoned parts of a mine in accordance with Mine Safety Board Decision avoids the necessity of rock-dusting the sealed-off openings.The kind of rock dust to be used should have the approval of the State Mine Inspection Service. Pure limestone or pare dolomite produces the best rock dust, as these dusts have low silica content, little tendency to cake, and a light color that aids illumination. To reduce tendency to cake it is preferable that not more than 75 percent of the dust pass the 200-mesh sieve. All sieve sizes are those of the Tyler screen scale. If the mine personnel is repeatedly exposed to breathing high concentrations of the dust, the percentage of free and combined silica should be as low as possible, preferably less than 5 percent. Persons engaged in the application of rock dust should wear approved dust respirators as listed in Bureau of Mines Information Circular 7030 or revisions thereof."

Mar 1, 1940

A compilation of papers presented at the Fourth WVU Conference on Coal Mine Electrotechnology in Morgantown, West Virginia, on August 2-4, 1978. Papers cover areas of electric power, electronic communications, detection and location of trapped miners, and electronic sensors and monitoring systems.

Jan 1, 1978

By John H. Johnson

This report covers the third and final year of work conducted under U. S. Bureau of Mines Grant G0166027, "Monitoring of Mine Air Pollutants". The report discusses work performed in three areas. These are the White Pine Mine (WPM) Experimental Unit, diesel mine-vehicle tailpipe emissions monitoring, and mine ambient air concentration data analysis. The WPM experimental unit was used to study diesel exhaust stratification in an 80 foot long dead-end heading while loading ore with a Wagner ST-5D scoop train LHD. The MTU Mine Air Monitoring Laboratory (MAML) was used to gather temperature and CO2 concentration data at 10 locations. Three different ventilation conditions were compared. The data substantiate the presence of strong buoyant forces of the hot exhaust gases which result in temperature stratification in dead-end headings. The diesel mine-vehicle tailpipe emissions monitoring study involved laboratory measurements of diesel undiluted exhaust pollutant concentrations by the portable tailpipe emissions measurement apparatus (EMA) assembled for in-mine use. The results were compared with simultaneous measurements by standard laboratory exhaust monitoring instruments. These results indicate that accurate field source quality control measurements can be obtained for CO2, CO and NO but NO2 results were low for all engine conditions. The mine ambient air concentration data analysis study included analysis of diesel pollutant concentration data in the Orchard Valley Mine air and comparison of the results with data collected earlier in the White Pine and Brushy Creek mines. The analysis included preparation of lognormal frequency distributions and calculations of C02-based concentration ratios and correlations. In the three mines compared, pollutant concentrations are distributed quite similarly, and the concentrations appear to be controlled to present standards.

Jan 1, 1979