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By ALICE V. Petar

Like many gem materials, amber has a colorful history which may be traced through the writings of the ancients and the ornamental relics discovered from time to time. Like few gem materials, however, it is distinctly useful in products whose value has no connection with the gem industry. Long prized for its beauty, amber was fashioned into articles of jewelry and ornaments to please the fancy of ancient rulers and to find a place among treasured pos- sessions in their tombs; it has been used by adherents of various creeds for rosaries and other religious symbols; and although still sold for these pur- poses it also lends itself to such commercial purposes as raw material for varnish. Amber is only on the border-line of the mineral kingdom; actually it is of vegetable origin, having been formed as resin from trees of the conifer family that existed during the Tertiary period. It is the hardest of the fos- sil gums. The United States produces no amber, although a few occurrences are known. Most of the world's supply comes from East Prussia, where it is ob- tained from both land and sea. For many years pieces of amber were gathered from the Baltic by fishermen and deep-sea divers; and although about 10 per- cent of the Prussian amber is still recovered from the sea, most of the out- put is mined from open pits on the Samland Peninsula.

Jun 1, 1934

By R. Hogg, Y. Lee, D. E. Rannels

"Lee, Yu-Chen, Richard Hogg, and D. Eugene Rannels. Extracellular matrix synthesis by coal dust-exposed type II epithelial cells. Am. J. Physiol. 267 (Lung Cell. Mol. Physiol. 11): L365–L374, 1994.—Although integrity of the alveolar basement membrane may influence progression of lung injury induced by inhaled particulates, little is known about direct effects of coal dusts on the alveolar epithelium or its extracellu¬lar matrix (ECM). Effects of dust on synthesis of cell and ECM proteins by type II cells (T2P) was thus investigated. Three coal dusts (anthracite no. 867; bituminous no. 1451 and no. 1361) and mine dust MIT-3, of respirable size, were studied as a function of dose and time over 3 days of primary T2P culture. On day 1, 750 µg/ml of 867 were required to increase relative synthesis of ECM proteins (ECM/cell). MIT-3, 1451, and 1361 were without effect. By day 3, 867 or MIT-3 increased ECM/ cell 60-100% at 300 µg/ml; 1451 produced modest, dose-dependent stimulation, whereas 1361 remained without effect. None of the dusts caused significant cytotoxicity. The results show dose- and time-dependent effects of well-characterized coal and mine dusts to modify partitioning of newly synthesized proteins into the ECM and suggest that coal dust exposure may modulate structure or function of the subepithelial basement membrane.basement membrane; cell culture; inorganic dust; lung injury; extracellular matrix deposition; pulmonary epitheliumCHRONIC EXPOSURE to coal dust may be associated with development of pulmonary fibrosis and consequent loss of normal lung function (see Ref. 26 for review). Al¬though the pathways of inorganic dust-induced lung injury are recognized to involve an inflammatory re¬sponse, the underlying pathogenic mechanisms are not understood in detail. Acute and chronic responses to dust exposure involve a variety of interacting cells of the immune system, including macrophages, T cells, and B cells, along with pulmonary fibroblasts. These responses reflect direct effects of the dust particles, as well as indirect effects mediated by soluble factors, including cytokines and eicosanoids (see Ref. 41 for review).Studies of pulmonary macrophages and fibroblasts following silica exposure suggest that dust-induced damage at the airway surface may involve cellular injury through oxidant-mediated pathways. Coal dusts and related inorganic particulates can activate the alveolar macrophage (42) to produce fibronectin (15) and cytokines, such as interleukin-1 or tumor necrosis factor (4) and/or other soluble products which act locally (29) to cause acute cellular injury and to initiate the progression of fibrotic lung damage (16). Type I epithelial cells are typically more susceptible than type II cells to oxidant injury. Type I cell damage and subsequent death leads to denudation of the subepithelial basement membrane (2, 21) and can be associated with leakage of plasma constituents from the pulmonary vasculature into the alveolar compartment (13)."

Dec 1, 1995

By Robert W. Freedman, Robert L. Craft, William G. Humphrey

As part of a continuing effort to reduce the weight and bulk of equipment that mining personnel must carry underground, the Bureau of Mines and the Mining Enforcement and Safety Administration (MESA) investigated accurate and convenient gas samplers for use by mine inspectors in sampling mine atmospheres. The samplers are septum-stoppered glass vials commonly used for routine blood sampling. These lightweight, compact samplers yield results comparable with those obtained with conventional bottle samplers of 250-ml nominal capacity.

Jan 1, 1975

By R. A. Pallanch

This paper, which describes the milling practice at the Midvale concentrator, is one of a series being prepared by the Bureau of Mines. The Midvale concentrator, a custom lead-zinc selective flotation plant, is in Salt Lake County, Utah, on a flat site several hundred yards east of the Jordan River and about 200 yards south of the Denver & Rio Grande Western Railroad tracks leading to Bingham Canyon. The site is at an elevation of about 50 feet above the river, the highest available location, thus allowing maximum storage of tailings.

Jan 1, 1931

By R. C. Hickman

Preliminary evidence indicated that the Chattanooga Shale might constitute a potential vast low-grade source of uranium. Investigation by core drilling indicated that while the Chattanooga Shale may constitute a resource for the future, the very low (0.006 percent) average uranium content is not economic when compared with the relatively higher grade western ores. A total of approximately 12,000 feet of test drilling was done in 72 drillholes, and large samples were mined for extractive and metallurgical testing. An experimental mine site was selected on the basis of the drilling project.

Jan 1, 1967

By Homer J. Ballinger

The Rex mine is one of several zinc deposits in Ozark and Howell Counties, Mo. It is the second of these deposits investigated by the Bureau of Mines in an effort to demonstrate reserves of sulfide ore underlying the shallow carbonate ores from which the district's major production has come. The initial investigation was made during 1945-46 on the Alice mine, Ozark County, Mo.21 The investigation reported herein was conducted during 1947. The Rex open pit is about 250 feet long, 100 feet wide, and about 25 feet deep (average). Three caved shafts are evident in the bottom of the pit, but the extent of the workings from these shafts is not known. The Bureau of Mines drilled five churn-drill holes in and around the Rex pit to test the grade and the vertical and lateral extent of the deposit. Two of the holes indicate notable zinc mineralization ranging from less than 1 to more than 10 percent metallic zinc, but largely in the oxidized condition.

Jan 1, 1948

By G. Richards Gwinn

"Mica" is a group name for a number of orthosilicates of aluminum with magnesium, ferrous iron, and the alkalies. They are characterized by their high reflection and a basal cleavage so well developed that they can be split into exceedingly thin laminae, which are more or less tough, elastic, and transparent, according to variety. Barium, manganese, lithium, chromium, titanium, boron, and ferric iron occur in same varieties. Eight distinct species of true mica, which appear in the following table, are recognized by mineralogists, but only the first five are of commercial importance. [Species General Formula Muscovite H2KA13 (SiO4)3 Phlogopite [H,K, (MgF)]) Mg3A1 (Si04)3 Biotite (H,K)2(Mg,Fe)2(Al)Fe)2 (S104)3 Lepidolite K,Li Al(OH,F)2 Al (5103)3 Ros coalite H8K(Mg,Fe) (A1,V)4 (S103)12 Paragonite H2NaAl3(S104)3 Zinnwaldite (K)Li)3 FeAl3 Si5016(OH,F)2 Lepidomelene HK2F3IIIFe6III A13 (S104)9]

Jan 1, 1951

By H. W. St. Clair

This study was undertaken to provide a more adequate knowledge of the chemistry of the sulfide volatilization process for recovery of tin from low-grade Bolivian ores. The investigation was partly supported by the Department of State under its program for scientific cooperation with South American republics. The results of this investigation demonstrate the conditions under which cassiterite (Sn02) may be converted to stannous sulfide by reaction with pyrite or sulfur vapor, Quantitative data are given on the rate of sulfidization and on the vapor pressure of stannous sulfide.

Jan 1, 1954

By Steven J. Schatzel

Large-scale methane releases in dual salt mines have resulted in ignitions and mine fatalities as recently as 1979. Several past studies have implied that hazardous methane occurrences in U.S. salt domes are distributed neither uniformly nor randomly, but are geologically controlled and potentially predictable. A first step by the Bureau of Mines in addressing the problem of methane in deal salt mines required development of a new test to determine volumes of gases in solid salt samples. This report considers the results achieved when 80 deal salt samples were tested for gas content by dissolution in a controlled atmosphere chamber. Criteria were organized to delineate salt types based on geological occurrence. Outburst samples range from 0.014 to 7.4 cm3 CH4/100 g NaCl, anomalous salt samples from 0.0027 to 2.6 cm3 CH4/100 g NaCl, and normal salts from less than 0.0003 to 0.31 cm3 CH4/100 g NaCl. The presence of higher hydrocarbons was most common in samples containing larger quan¬tities of methane. The presence of higher hydrocarbons appears to be useful in detecting methane hazards where some methane may be lost before gas content testing. An exploratory rotary and/or core drilling program, dissolution testing for gas content, and up-to-date geologic mine napping could allow a mine operator to assess methane hazards in dual salt.

Jan 1, 1984

By Michael Gibbons

A method of monitoring roof stability in underground mines by detecting the changes in resistivity of roof material was tested. The device built by the USBM was tested over a 16 month period at the White Pine Copper Mine in White Pine, Michigan. Three falls of ground were monitored by means of as many as 11 sensors. Data indicate a correlation between changes in resistivity and impending structural failure. Problems were encountered with the high roof electrode impedance in the winter and spring due to the drying out of the roof material. Difficulties also developed in obtaining a permanent bond between the roof rock, the conductive epoxy and the electrode plate. Some data were lost due to timer and fuse problems within the unit. These were eventually rectified.

Jan 1, 1979

By Hanns J. Billmayer

This report, which covers the period from June 15, 1974 to May 30, 1975, describes the work performed in compliance with the requirements of Contract No. H0242065 and modifications 1, 2, and 3 thereto. The purpose of the original contract was to equip the second shuttle car in the Jewell Ridge No. 12 mine, section 6R, with a refined design canopy and seats. In addition, several refinements and improvements were to be designed and installed at the same location on the cutter and the loader. However, during October 1974 in response to a request from the Technical Project Officer, the contract was modified to eliminate all of the cutter and loader tasks and substitute the design, fabrication, and installation of an improved canopy on the no. 2 roof drill in the above mentioned section of the Jewell Ridge No. 12 mine.

Jan 1, 1975

By Terry J. Kreidler

In recent years, west-central Arizona and adjacent California have become the focus of geologic and exploration attention because of its excellent exposure of detachment-fault terrane. Detachment faults, normal faults with nearly horizontal fault planes, are the result of regional extension. Rocks on the lower plate consist of mylonitized intrusive, metasedimentary and crystalline rocks highly altered to chlorite; upper plate rocks comprise sedimentary, volcanic, metasedimentary, and metavolcanic rocks. The movement of the detachment fault causes the rocks on the upper plate to be severely fractured and brecciated thus making them Ideal conduits for mineralizing fluids. Mineralization favored the more reactive sedimentary and volcanic rocks of the upper plate. Three gold deposits, located in upper plate rocks, are currently being mined along the Colorado River corridor: the Picacho Mine near Yuma, Arizona, 70 mi south of the study area; the American Girl Mine In southeastern California, 60 mi southwest; and the Copperstone Mine near the southern end of this study area. Samples from the above three mines were used to create a geochemical model of detachment-related gold deposits. Antimony, arsenic, barium, copper, mercury, molybdenum, manganese, tungsten, and zinc all occur In the mine samples in concentrations at least three times greater than found elsewhere in similar rock types. Samples taken by the Bureau from the wilderness study areas contain similar anomalous concentrations of the same elements as well as elevated concentrations of several other elements Including: lead, fluorine, cerium, uranium, and samarium.

Jan 1, 1992

By John Paul Gries

During World. War II, when the curtailment of imports led to an unprecedented demand for domestic mica, beryl, spodumene, and other pegmatite minerals, the Bureau of Mines and the Geological Survey entered upon a program designed to expedite mining of these minerals from the Black Hills area of South Dakota. The program involved napping, sampling, and drilling of many pegmatite dikes in the southern portion of the Black Hills and beneficiation conducted in the field and in the Bureau of Mines laboratories at Rapid City, S. Dak., Rolla, Mo., Salt Lake City, Utah, and College Park, Md. This report describes the occurrence and sampling of the Beecher No. 2 pegmatite, which was investigated as part of the general pegmatite study in South Dakota. Investigation of the Beecher No. 2 pegmatite was started on November 20, 1943, and terminated in the spring of 1944. During this period, the Bureau of Mines took a series of trench samples across the pegmatite at the surface for grain-count studies and chemical analyses. The Geological Survey mapped the geology of the deposit after it was exposed by trenching and stripping.

Jan 1, 1950

By Franklin H. Persse

Domestic bismuth supply was projected from production figures for the ores in which it occurs--copper, lead, zinc, and tungsten. Published and unpublished data concerning host ores were examined to determine bismuth reserves and resources, and mine production. Potential recoverable bismuth occurring with reserves and resources of copper, lead, and zinc was estimated to be 36.3 million pounds. A bismuth availability diagram was developed from quantity estimates and ratios of production cost to value for these host ores. Additional recoverable bismuth occurring with domestic tungsten reserves was estimated to be 1.5 million pounds. Domestic byproduct production of bismuth will approximate 1.3 million pounds annually by 1980. This quantity will provide about 37 percent of the 3.5-million-pound estimated requirement for that year. Known world supply of bismuth appears to be sufficient for world demand to the end of this century. The study indicates that bismuth reserves and potential resources in the rest of the world have not been adequately reported.

Jan 1, 1970

By P. H. Mutschler

The Bureau of Mines studied the Chattanooga Shale to determine the quantity and quality of the uranium resources present and to assess specific environmental effects of mining the shale. Geologic data and chemical analyses, mainly concerning a 12-county area of Tennessee, were compiled from previous published and unpublished reports. Uranium resources in the Gassaway Member of the Chattanooga Shale in this 12-county area were estimated to be between 4.2 and 5.1 million tons, contained in 76 to 91 billion tons of shale. These figures represent inground tonnages and do not allow for mining or processing losses. Depending upon efficiency of mining and processing systems, enough uranium could be available to satisfy a large part of the cumulative domestic and world demand through the year 2000. A model was developed which assesses the total tons or acres of shale to be mined if the Gassaway Member were to satisfy 1 percent of the United States demand for uranium in 1991. This partially demonstrates the environmental impact of mining the shale and is easily factorable to any specified demand.

Jan 1, 1976

By J. B. Gayle

Coke-pushing difficulties have been the subject of much controversy but relatively little scientific investigation. Nevertheless, continuing pushing difficulties can greatly decrease the life of a coke oven and should therefore be considered in the selection of the blend and operating conditions used for coke production. The present Federal Bureau of Mines investigation was undertaken to correlate results of previous investigators and to supplement these results to the limited extent practical by us of an experimental slot-type oven. To this end, pushing pressures have been determined routinely for Tuscaloosa oven tests conducted during the past 10 years. Nevertheless, the accumulated information remains incomplete in many respects, and in view of the recognized inadequacies of the data, publication is now undertaken only because of the scarcity of published information on this important problem and the discontinuation of carbonization studies with this oven.

Jan 1, 1961

By E. J. Murphy

"INTRODUCTION This investigation is a continuation of previous work 3/4/5/ on the gaseous products of permissible explosives with and without sheaths. The range of oxygen balance of the explosives has been considerably increased. As has been shown previously, certain approximate relations exist between the volumes of gaseous products and the oxygen balance. Further systematization of the data is not feasible, since the method of theoretioal calculatln of the gaseous product is not yet satisfactorily developed. In a previously described method, 6/ it has been assumed that the explosion occurs at constant volume and that thermodynamic equilibrium is established. Apart from the presumably less important uncertainty of some of the thermodynamic data, it is not known how the confinement of the shots in the Bichel gage or the Crawshaw-Jones gage should be treated, or whether thermodynamic equilibrium is fully attained; nor can the extent to which the equilibrium composition changes during the subsequent period of expansion and cooling be judged with any reliability. Therefore, no calculations have been attempted. However, in anticipation of possible future theoretical interest and as an aid in answering practical problems, the new data are presented in the same minute detail as was done previously."

Mar 1, 1948

By Mark Sheppard

This paper is the second of a series recording the results of tests made at various quarries throughout the United States to determine, (1) the relation between the size gradation of feed to, and product from, primary crushers; (2) the particle shape of crushed product; (3) the differences in gradation and particle shape produced by different tries of primary crushers; and ( 4) the differences in gradation and particle shape caused by crushing different kinds of stone. Primary crushing has received comparatively little attention in the technical literature in spite of tine fact that the design of the whole crushing plant should be correlated to the performance of the primary crusher.

Jan 1, 1938

By Jr. Norman

Thermoelectric properties of depleted uranium selenides and tellurides were investigated from room temperature to 700 C. Several depleted uranium monoselenides and monotellurides were doped with selected cationic and anionic materials to determine the effect of impurity additions on the thermoelectric properties. The undoped uranium selenides and tellurides were semimetallic conductors exhibiting low Seebeck coefficients and electrical resistivities. Partial or complete degeneracy was in evidence, indicating a charge carrier energy distribution similar to that in a metal. Doping increased the Seebeck coefficients of the uranium monoselenides and monotellurides; however, the corresponding change in the power factor in the figure of merit was small because of the increase in electrical resistivity.

Jan 1, 1965

By Charles L. Kimbell

Comprehensive world mineral industry investment data do not exist, but limited material published on aggregates of in vestment in some elements of the world mineral industry suggest a continued up-turn in the investment level, at least in market economy countries in 1989. Steel industry investments in Organization for Economic Cooperation and Development (OECD) countries are not yet available for 1989 but, as shown in table 6, increased by 22.1% in 1988, after showing a decrease of 5.2% (revised) in 1987. The pattern of investment ups and downs varied during 1988 within country blocs and economic alliances showing no particular trends. Investment in the steel industry by the United States increased by 58.3% between 1987 and 1988 and was 1 1.9% higher than the previous highest amount invested during the 1984-88 period but was still 41.5% less than the amount invested in 1983. Investment in the steel industries of the European Coal and Steel Community (ECSC) dropped again in 1988 from the revised amount for 1987, which became the first drop after several years of steady growth in what became the expanded ECSC in 1986. This drop in 1988 was the result of lower investments by Denmark, France, the Federal Republic of Germany, Ireland, Italy, Luxembourg, the Nether- lands, and Spain, investments grew or remained level in Belgium, Portugal, and the United Kingdom in 1987 and 1988. A decrease in investment in the Canadian (-26.6%) steel industry was offset by in- creases registered by the members of the European Free Trade Association (EFTA) of 31.7%, by Japan of 19.8% by Turkey of 22.4%, and a slight increase by the nations of Latin America. If data for the world steel industry as a whole, including those of the centrally planned economy countries, were available, the same pattern presumably would be shown as that reported; that is, it would remain fairly stable, with increases in some countries being offset by decreases in others. However, the lack of comprehensive information on the centrally planned economy countries makes it impossible to determine whether the overall trend was up or down despite recorded increases or decreases in production of the materials involved. Preliminary data show that investment levels in industries dealing with the production and/ or processing of mineral commodities for

Jan 1, 1992