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By W. L. Dare

This circular is the first of a series of publications describing uranium mining on the Colorado Plateau. Later circulars are planned in which exploration, development, and mining methods and costs will be described after a detailed study of various operations. Because of the introductory character of this paper, those well-publicized phases of the industry such as geography, history, prospecting, and exploration are described but briefly. Primarily, attention has been devoted to the general problems that are encountered in mining ore bodies and to the factors that affect the selection of development and mining methods. Those familiar with mining may class the information contained in this paper as elementary; however, its inclusion is considered necessary for the completeness of the series of papers. It will also serve as a source of information for people who are interested in uranium but are unfamiliar with mining.

Jan 1, 1955

By M. C. Malamphy

A general description of the activities and results of bauxite investigation by the Bureau of Mines at its bauxite project in Saline and Pulaski Counties, Ark., has been given in Report of Investigations 4251. The factual data obtained during the project are reported in a series of Reports of Investigation beginning with No. 4251, of which this is the fourteenth. The data are accompanied by maps showing the location of holes drilled and the deposits developed. Each area upon which work was done is reported by half townships. Each bauxite deposit investigated was assigned & name and a number for ready reference and identification, and its location and name are shown on the appropriate half-township map. The description of each half township is followed by a description of each deposit developed in that half township. The 14 half-township maps and 77 detail maps of the bauxite deposits in this series of reports give the locations and numbers of all the holes drilled except the deep holes drilled to test geophysical anomalies. The locations of those holes are shown on figure 13 in volume 1. The descriptions of the deposits developed are followed by complete detailed logs of the drill holes. Many of the widely spaced exploratory holes did not discover bauxite of minable thickness and grade. The pertinent information obtained from the widely spaced exploratory drill holes has been summarized and tabulated, and a table for each half township is given with the discussion covering that area.

Jan 1, 1948

By Changwoo Lee, Jan M. Mutmansky

"This paper results from the research at The Pennsylvania State University into establishment of standard procedures for characterization of respirable coal dust performed by the Generic Mineral Technology Center for Respirable Dust and supported by the U.S. Bureau of Mines and the Mining and Mineral Resources Research Institute at The Pennsylvania State University. The research performed within this particular project is oriented primarily toward standard methods of sampling and characterizing respirable coal mine dust underground so that the chemical, physical, and morphological characteristics are known and can be related to the incidence of coal workers' pneumoconiosis (CWP) in Pennsylvania.The research was initiated by con¬ducting a search of the literature to determine what coal and geologic variables may be related to CWP. The effects of coal rank, free silica content, the mass of respirable dust, and the level of trace elements were the major variables studied. It seems to be evident that the free silica content, the rank of coal, and the mass of respirable dust are the major concerns in defining the causes of CWP. However, based on the literature survey, the authors have concluded that verification of the causes of CWP is a multivariate problem and must be analyzed in an appropriate statistical manner.The results of a multivariate analysis of ten trace elements recorded on Pennsylvania coals are presented. Five of these trace elements were found to be of use in differentiating one coalfield from the others. Of these five elements, chromium and zirconium showed a strong positive correlation with the rank of coal while strontium showed a negative correlation.The design of the field sampling work and its application in future research is the final topic discussed. The sampling plan is oriented toward continuous miner sections with eight-stage impactors as the collection equipment. All of the field work will be conducted in the coal measures of the Allegheny Formation and above with both dust and channel samples being collected in the same mines.Coal workers' pneumoconiosis has been an important topic of concern to miners, mining engineers, and epidemiologists for decades. The general cause of the dis¬ease, the inhalation of coal mine dust, is well known, but the specific coal and geologic variables that affect the incidence and severity of the disease are still subject to debate and study. The primary objective of this study is to identify those variables of Pennsylvania coals that contribute to the CWP problem. To accomplish this task, a field sampling program is to be conducted to relate the characteristics of the coal dust, the coal seam properties, and the geologic variables to the occurrence of CWP.The first year of this study has been involved with both a literature review and experimental work oriented toward identification of causal variables related to CWP. The results of this work are presented here along with plans for implementation of the findings in future research.The previous studies of CWP causal variables have been conducted by scientists, engineers, and medical personnel. Many different types of studies have been performed with emphasis on interpreting the effects of dust mass concentration, mineralogy of the coal, the rank of the coal, and trace element concentrations upon the incidence of CWP in various coalfields. Most of the research has been conducted during the last two decades, with the British Isles, West Germany, and the United States being the primary countries involved.The review of the literature was conducted to determine which variables are likely to warrant further study in Pennsylvania. Previous research studies have related CWP to free silica and other mineral content, the rank of coal, the mass of dust in the working place, and the trace elements in the coal and lung dust. In the following sections, each of these topics will be discussed and analyzed."

Jan 1, 1988

By D. Harrington

Most of those in the Health and Safety Branch, Bureau of Mines, necessarily participate in activities associated with essentially all phases of the mineral industries, including coal and noncoal mines, quarries, smelters, metallurgical plants, and various petroleum operations. One of the strictly war activities of the branch - the Explosives Control Division, which administers the Federal Explosives Act of December 26, 1941 - has functions that require contacts not only with nearly all phases of the mining and allied industries but also with those engaged in scores of other occupations that manufacture, store, use, or possess explosives, or many of the ingredients of explosives. The field men of the Health and Safety Branch (approximately 300 in number) Are occupied full time in health and safety activities and annually make thousands of contacts with people in the mineral industries as well as the plants in which they work. From these they formulate several thousand written reports containing sources of thousands of conclusions and recommendations aimed at reduction of health end safety hazards in these industries. Although such activities have been greatly increased during the war and immediate pro-war periods, they have been in effect to a considerable extent since the Bureau of Mines was created in 1910.

Jan 1, 1944

By Chas. F. Jackson

During the current business depression the Bureau of Mines has received many inquiries concerning placer mining, the prospects for men of small means to make wages by small-scale placer operations, the locations of placer deposits in the United States, methods of working placers on a small scale, and allied subjects. It has therefore seemed desirable to prepare a circular covering, in nontechnical language, the principal questions which have boon referred to the Bureau of Mines for answer. There are a number of bureau publications dealing with placer mining, most of which are now out of print, but which may be consulted in the larger libraries. Other articles on placer mining nave appeared from time to time in the technical press and several good textbooks have been written on the subject. A partial bibliography of this literature appears at the end of this paper. A recent pamphlet published by the Idaho Bureau of Mines and Geology to assist the prospector and inexperienced small operator has received wide and favorable attention and is recommended as a useful reference. In the present paper no attempt will be made to cover the subject of placer mining in a comprehensive manner, but discussion will be confined to elementary questions of particular interest to persons of limited experience.

Jan 1, 1932

By Jr. Watts, B. K. Cantrell, D. H. Carlson, K. L. Rubow, S. T. Bagley

"Permissible exposure limits (PELs) have been established for gaseous pollutants, carbon monoxide (CO), carbon dioxide (CO), nitric oxide (NO), nitrogen dioxide (NO2), and some gas-phase hydrocarbons emitted in diesel exhaust. There is, as yet, no PEL recommended for diesel exhaust aerosol (DEA), nor is there a standard method for sampling this aerosol.The University of Minnesota and the U.S. Bureau of Mines have collaborated to develop a personal diesel exhaust aerosol sampler (PDEAS) which utilizes size-selective inertial impaction and gravimetric analysis. During the field tests of this sampler, numerous air quality measurements were made in underground coal mines that use diesel equipment.The mine mean DEA concentrations for the five mines surveyed, determined with the PDEAS in the haulageway, was 0.89 mg/m3, with a standard deviation of 0.44 mg/m3. DEA contributed 52 % of the respirable aerosol at this location.In three of the mines filter samples were collected for DEA-associated polynuclear aromatic hydrocarbons (PAHs) and biological activity determinations. Two of the mines were also monitored for the major gaseous constituents found in diesel exhaust. In general, the PAH and biological activity levels were similar for all three mines, and indicate that up to 25 % of the haulageway concentrations may be contributed by outby diesel vehicles. Measured concentrations of CO, CO2. NO, NO2, and SO2, were well below regulated levels.INTRODUCTIONDiesel exhaust contains pollutant gases, such as carbon monoxide, carbon dioxide, nitric oxide, nitrogen dioxide, and gas-phase hydrocarbons, as well as DEA. Much of the health-related concern focuses on DEA and associated organic compounds (Watts, 1992a). A wide variety of these PAHs have been identified and some are known carcinogens and/or mutagens. The U.S. Mine Safety and Health Administration (MSHA) has proposed new PELs for these and other contaminants (MSHA, 1989). MSHA has also published an advance notice of proposed rulemaking to establish a separate PEL for diesel particulate (MSHA, 1992)."

Nov 1, 1995

By Homer J. Ballinger

The Krueger property was examined by an engineer of the Bureau of Mines in September 1943. The records of 23 old drill holes indicated an appreciable body of ore without delimiting the deposit. It appeared that additional drilling might increase this reserve sufficiently to justify mining. Accordingly, the Bureau of Mines drilled 5 churn-drill holes and 19 diamond-drill holes on the Krueger tract. The last of these holes concluding the Bureau?s project was completed in April 1947.

Jan 1, 1948

By J. A. Woolf, E. S. Leaver, A. P. Towne

"INTRODUCTION A report giving experiments dealing with factors affecting the floatation of the most commonly occurring silver minerals was published years ago. At that time we could not obtain suitable samples of many of the so-called sulfo-salts of the base metals, which are generally silver--bearing and which comprise an appreciable percentage of the natural silver ores. Since Leaver and Woolf's work was published, samples of impure tennantite and enargite have been obtained, and considerable experimental flotation work has been done with synthetic mixtures prepared from these samples. During the present national emergency, research dealing solely with the recovery of gold and silver must necessarily be curtailed. However, many deposits of strategic minerals and critical base metals contain an appreciable amount of gold and silver, the recovery of which would aid greatly in recovering the strategies by taking care of a considerable part of the cost of treatment. Because of this, the recovery of precious metals should not be overlooked entirely. As the Bureau of Mines is now utilizing all of its facilities for the development of increased domestic productions of strategic and critical minerals, this is the last report not concerned primarily with such minerals that will be published until the war ends."

Sep 1, 1942

By D. A. Reynolds, J. D. Davis

"INTRODUDTION Investigations by the Bureau of Mines have shown that the carbonizing properties of splint and bright coals may differ greatly. In a study of 55 coal columns selected from representative coals of the Appalachian region, Sprunk and coworkers 10/ compared various chemical and physical properties of splint and associated bright coals. Carbonization tests in the Fischer retort at 932°F. (500°C.) showed that, except for bright coals of high oxygen content, the coke residue from bright coal was much more swollen and cellular than that from splint. ·with one exception, agglutinating values determined by the Bureau of Mines test, were lower for splint than for associated bright coal.Because sorting of coal in quantity is tedious and time-consuming, separate types have not been carbonized by the Bureau of Mines-American Gas Association (BM-AGA) test, which requires 85- to 200 pound charges. However, this method has been used to determine the carbonizing properties of samples 0f bed layers that are composed largely of either splint or bright coal.4/ In these earlier tests, which were made at high temperatures on layer samples from the Elkhorn bed, Letcher County, Ky., the splint coal yielded more coke than the bright coal, and this coke was slightly stronger than that from the bright coal. The cokes from samples with large proportions of bright coal were more cellular or porous, as were the low-temperature cokes obtained from carbonization of separated samples of bright coal in the Fischer retort."

Apr 1, 1944

By Edmund S. Leaver

[In previous reports5/ of ore-testing studies standard methods of conducting; test with precious-metal ores selected as representative of certain mining districts were discussed in considerable detail. In addition to standard tent procedures such as direct cyanidation, amalgamation, gravity concentration, and flotation, or a combination of these methods, it is sometimes necessary to apply other methods, such as preliminary roasting and washing of the calcine with plain or acidulated water before cyanidation. In all of this work standard tenting procedure has been supplements by he necessary assaying and analyses of original ore and test products.]

Jan 1, 1941

By Edmund S. Leaver

[In previous reports 5/ of ore-testing studies standard methods of conduction tests with precious-metal ores selected as representative of certain mining districts were discussed in considerable detail.]

Jan 1, 1941

By F. W. Brown, F. C. Gibson

"INTRODUCTION There is urgent need for a satisfactory permissible multiple-shot blasting unit capable of firing 10 detonators in series and safe for use in underground mining where a. gas-ignition hazard may exist.. As there is at present no entirely satisfactory permissible unit of either the battery or generator type, tile described capacitor-battery type has been developed. Consideration of the Bureau of Nines approval schedule pertaining to the generator and magne to-type units and of the electrical characteristics of the unit described in this report indicate that this unit should meet Bureau of Mines permissible requirements.This report gives a detailed description of the design and operation and results of tests to determine safety of operation in gassy atmospheres.DESIGN AND OPERATION OF UNITOperation of the vibrator-type multiple-shot blasting unit is based upon utilization of the discharge energy from a capacitor charged to a given. voltage and having capacitance adequate to store enough energy to initiate 10 detonators in series. The primary source of energy is a 4-volt cap lamp battery such as is carried for illumination on the person of underground workers in nearly all mines. As this battery is already available and is recharged daily it is considered to be a reliable and convenient source of energy for a blasting unit. Figure 1 is a schematic diagram of the circuit for an improved unit, and figures 2 and 3 are views of the experimental unit. The battery potential is applied through a radio-type synchronous vibrator (8) to an 8-volt center-tapped primary of a small transformer (9) having a high-voltage center-tapped secondary. The vibrator introduces an alternating low-voltage potential into the primary and mechanically produces full-wave, rectified, pulsating, direct current from the secondary. A buffing condenser (11) across the secondary gives the proper wave form for long vibrator life: a resistor (12) its in series with this condenser across the total secondary to protect the transformer in case of• failure .of this capacitor. A voltage divider (10) with an adjustable slider permits accurate adjustment of the potential applied to the high-capacity firing condenser (5)."

Oct 1, 1947

By H. W. Clair, E. V. Potter, M. J. Speedlove

"INTRODUCTION The behavior of particles in a sound field has long been of scientific interest since Kundt (1) 5/ made his classic experiments on some of the interesting effects of standing waves in cylindrical tubes. With the development of the electronic tube and its application to continuous generation of sound, experimental investigation of the Kundt tube was renewed (2). The more intense vibrations set up by a continuously vibrating diaphragm or rod produce even more striking effects than those observed by Kundt. Instead of the striations at the antinode produced by the stroked rod, then, wafer like barriers are formed at the antinodes, sometimes extending over the entire cross-section of the tube. Furthermore, it was observed independently by Andrade (3), Brandt, Freund and Hiedemann (4); and by investigators in the Bureau of Mines laboratories (5) that aerosols, such as ammonium chloride or tobacco smoke, could be flocculated quickly if passed through an intense sound field, particularly when a standing wave field was set up by a resonant enclosure. Because of its possibilities as a new means for removing suspended particles from dust-laden gaseous furance or smoke, the phenomena attending the behavior of suspended particles in a und field have been studied intermittently by the Bureau of Mines over the past decade.The first experimental work was done with a magnetostriction vibrator and a Hartmann air-jet generator as sound sources. It soon became evident that neither type was entirely satisfactory. Low mechanical efficiency is an inherent characteristic of magnetostriction generators, and the air-jet generator is difficult to control and does not permit accurate measurement of the acoustic output. The search for a suitable sound source led to the development of an electromagnetic generator, which is by far the most suitable for study of the effects of intensive high-frequency sound fields in gases (6)."

Mar 1, 1948

By F. A. Rutledge

Mercury deposits were discovered in 1941 in the sedimentary rocks of the Cinnabar Crook area, near the head of the Holitna River drainage in southwestern Alaska, by Russell Schaefer and Harvey Wincholl of Sloitmut, Alaska. High-grade float was found in both Canary Gulch and Cinnabar Gulch, and indications of other deposits wore found in Aldor and Broken Shovel Gulches. Schaefer and Winchell's exploration in 1942 and 1943 revealed placer deposits of cinnabar along Canary Gulch. During prospecting on Canary Gulch, 3,600 pounds of ore was recovered from the detrital material on the Lucky Day lode at the head of the gulch. When retorted, this ore was reported by the owners to have produced 26 flacks of quicksilver. During the summer of 1943, Wallace M. Cady and Charles A. Hickcox, of the U. S. Geological Survey, spent 4 weeks mapping and investigating the area. Bruce I. Thomas and Harold C. Pierce, mining engineers of the Bureau of Mines, examined and sampled several deposits in September 1943. Following their preliminary examination, in view of the exceptionally high-grade cinnabar present, additional investigation by the Bureau of Mines was recommended. A program of trenching, test pitting, and sampling to delimit the deposits was completed during the summer of 1947 under the direction of the author.

Jan 1, 1950

Limestone formations in the United States can be subject to relatively high horizontal stresses due to the existence of tectonic loading of the limestone strata. Underground limestone mines use the room-and-pillar method, in which 12- to 18-m-wide rooms are typically excavated. The stability of these excavations can be compromised by the horizontal stress, resulting in a rockfall hazard. Rockfalls are the cause of 15% of all reportable injuries in underground limestone mines. Horizontal stress related damage can occur in the form of guttering along one or more sides of an excavation, roof beam buckling or oval shaped roof falls, with the long axis perpendicular to the major horizontal stress. Numerical analyses show that the pillar layout and orientation of the mine workings have an effect on the horizontal stress distribution within the roof. The effects of high horizontal stresses can be mitigated by orientating the heading development direction parallel to the maximum horizontal stress, reducing the number of cross-cuts and offsetting the cross-cuts to limit the potential lateral extent of horizontal stress related roof falls. The modeling approach described in this paper can be used as a tool to evaluate potential roof failure and optimize the stability of room and pillar layouts.

Jan 1, 2008

By David A. Benjamin

In 1986, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied part of the 24,600-acre Orejana Canyon Wilderness Study Area (OR-001-078), in order to evaluate its identified mineral resources. The study area, located in Harney County, 76 mi northeast of Lakeview, OR, is underlain by Miocene basalt, rhyolite flows, tuffs, and tuffaceous sedimentary rocks. No mines, prospects, or claims were found within the study area. According to the U.S. Bureau of Land Management, the tuffaceous rocks have a moderate favorability for the occurrence of diatomite and a low favorability for zeolite resources. Also, the rhyolite flows have a low favorability for the occurrence of perlite resources. However, U.S. Bureau of Mines' studies indicate that no metallic or nonmetallic resources are present in the study area.

Jan 1, 1987

By R. V. Ramani, W. Miola, R. Srikanth, S. C. Soboleski

"Dust control in high-production longwalls requires attention to operating practices and ventilation schemes. Several studies have shown that the shearer is the major source of dust on a longwall face. Support movement has not been regarded as a major source of dust in US longwalls. Yet, under certain conditions, 31% of the shearer operator's dust exposure can be due to support movement.Several methods have been developed for the control of shield-generated dust. But the need for better methods is apparent. In this paper, the amount of airborne, respirable dust generated per shield move is estimated from specially designed experiments on longwall faces. Ten experiments were conducted on five longwall faces in four mines. Each experiment involved one face visit and lasted three to six hours. The contribution of shield movement to the airborne, respirable dust concentration immediately downwind of the shield move varied between 0.12 and 1.75 mg/m3 in the five longwall faces. The mass of airborne, respirable dust gener-ated by shield movement was found to vary between 39 and 386 mg per shield move. The results from this study reveal that control of dust from longwall shields requires a combi-nation of approaches involving alternative operating prac-tices, reducing shield dust generation rate, increasing face air flow and decreasing personnel exposure.IntroductionIn 1992, longwall mining accounted for about 36% of US underground coal production, a 240% increase from a decade ago. The absolute longwall tonnages were 46 and 133 Mt (51 and 146 million st), respectively. Compared with room-and¬pillar mining systems, the longwall mining system is charac¬terized by higher recovery, enhanced safety and higher pro¬ductivity.However, personnel dust exposure on a longwall face is higher than in other types of mining. According to Mine Safety and Health Administration (MSHA) data, fewer longwalls were in continuous compliance with the applicable dust standard in 1992 than in 1989.Controlling shearer-generated dust and reduction of per-sonnel exposure to airborne dust have commanded attention in the design of longwall faces, operational practices and ventilation schemes. Studies in the United States and abroad have revealed that support-generated dust can be a major obstacle to compliance under certain conditions (Becker et al., 1989; Bradley et al., 1983; Jankowski and Organiscak, 1983; Jankowski et al., 1990; Organiscak et al., 1985)."

Dec 1, 1996

By V. M. Benson

A simplified, routine method for determining lithium in lithium-bearing rock is presented. The sample is decomposed by repeated treatments with nitric, hydrofluoric, and perchloric acids. Since this procedure does not appreciably dissolve beryl, interference by beryllium (the principal interfering cation) is minimized for most samples. The salts are brought into solution with water and enough citric acid-ammonium citrate buffer is added to make the final volumetric dilution 0.20 M with respect to citrate. The addition of citrate greatly reduces anion interference in the hydrogen-oxygen flame, slightly increases the intensity of the lithium 671 millimicron emission line, and reduces the effect of most of the interfering cations to the extent that analytical separations are not necessary. The accuracy of results of single determinations of lithium in a pegmatite containing spodumene, lithium-bearing mica, and beryl are approximately equal to that obtained by other flame methods, INTRODUCTION This investigation was undertaken in Bureau of Mines laboratories to develop a reliable, rapid, routine analytical method for determining lithium in lithium-bearing minerals. The requirements of the procedure were that the method should be applicable to the analysis of a variety of lithium-bearing ores and test products, and the results would be reasonably accurate for materials containing 0.05 to 8 percent Li20.

Jan 1, 1961

By W. J. Long

The gradual depletion of high-grade mineral deposits and the necessity for development of lower-grade deposits together with the increased demand for nonmetallic minerals has increased the importance of the ore-dressing field during recent years. There is strong need for development of new ore-concentration methods and-machines to keep pace with the constant changing of marketing specifications and requirements resulting owing to the many new uses made of mineral products by the metallurgical industry.

Jan 1, 1948

By Wilbur A. Haley

The demand on the nation's reserves of high-quality coals suitable for metallurgical purposes is resulting in the rapid depletion of some of the thicker coal beds. These beds are thick enough to permit the use of modern mechanized mining equipment. Many of the thin beds are not being mined at present. In limited areas where the coal is less than 36 inches thick some beds are mined by various conveyor methods. Usually, the room-and-pillar system or some modification of it is used, and often no attempt is made to extract pillars. Consequently, an appreciable quantity of a valuable resource is lost. Many steel companies and coal operators consider reserves of low-and medium-volatile coking coals to be critical, especially in areas where the thin beds are not being mined by modern mining methods. To improve recovery and to promote more-extensive mining in thin beds, methods and devices that are new to American coal mining but applicable to the mining of thin coal beds should be tried. As one of the functions of the Bituminous Coal Mining Section of the Bureau of Mines is to promote improved mining practices and efficiency in the interest of conservation, research in that line is necessary. In 1945 coal planers were observed in operation in Germany by a Bureau engineer member of Solid Fuels Mission to Germany. Planer designs and history of early developments and operations were published. In 1949 an improved planer was again studied by Bureau engineers, and its adaptability to certain conditions in the United States, especially thin beds of friable coal, was considered practicable. After the war the planer was improved, in design and for several years has been operating successfully in the Ruhr. Because of the conviction that the device would be successful, both from the standpoint of conservation and operational prodl1ctivity, under certain conditions in the United States, the Bureau of Mines, through the Bituminous Coal Mining Section, entered into a cooperative agreement with the Coal Division of Eastern Gas & Fuel Associates and Mining Progress, Inc. The purpose of the agreement was to conduct an experiment in modified longwall mining, using a new-type German-built coal plow or planer, known as the Loebbe Habel, supplied by Mining Progress, Inc. The experiment was made to determine if this type of mining equipment operated on a longwall face could be adapted to some of the thinner American coal beds. Such an experiment also would afford many opportunities to study the possibilities and principles of this type of equipment as well as the many factors involved in the mechanical mining of a longwall face.

Jan 1, 1952