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By M. M. Myers

"Importance pf the small stone problem.Profitable disposal of limestone too small for making lime in the shaft kiln, is one of the most urgent problems in the lime industry. Reports received by the Bureau of Mines from 31 quarries show that the proportion of small stone varies from 2 to 40 per cent, averaging 18 per cent of gross pro¬duction, Modern methods of heavy blasting, and the use of crushers in large quarries tend to increase the proportion of small stone above that produced in early days when light blasting and hand sledging were almost universally used. There is also a growing movement toward underground operation of lime deposits, a method which in general produces a greater proportion of fines than is encountered in open-pit work. Thus the small stone problem is of growing importance, and demands the attention of every progressive lime producer. As the problem is of almost universal interest, it is urgently desired that every operator who reads this report will contribute from his knowledge or experience, answers to the questions on the final sheet.There are several markets in which small stone may be sold but in these markets the competition is generally keen and the prices low. The lime producer's chief product is lime, he understands its manufacture and marketing, and brings him a greater return than can be obtained from most limestone by-products. For these reasons it is evident that the conversion of small into lime is the nest desirable means of disposal."

Apr 1, 1924

By L. M. Burman

The phase-boundary pressure required to maintain a natural hydrocarbon fluid in a single phase must be considered in planning the recovery of reservoir liquids by miscible-phase processes. The change in the phase-boundary pressure at reservoir temperature that results when a light component or a mixture of light components is added to a reservoir fluid is an especially important consideration. The cricondenbar pressure (maximum phase-boundary pressure) and the critical pressure are unique correlated pressures that have been utilized to calculate the change in phase-boundary pressure that may result when the composition of a reservoir liquid is altered by an additive. In this study one reservoir oil and three gas-condensate fluids are used as examples. Correlations pertaining to the critical and cricondenbar states in chapters 4 and 5 of Bureau of Mines Monograph 10 (3)5 were used to demonstrate how butane and lighter components added to these reservoir fluids affect their phase-boundary pressures.

Jan 1, 1962

By E. P. Carman

In this report, the Federal Bureau of Mines presents a summary of the occurrence, properties, and uses of some natural bitumens, using the layman's or dictionary definition of bitumens - that is, naturally occurring hydro-carbons. Emphasis is on the less common solid and semisolid bitumens, particularly those occurring or used to some extent in the United States. This comprises data from many sources and references to these sources for more detail than is given in this summary. This paper was prepared primarily to answer questions about some of the less known bituminous materials. The word hydrocarbons could just as well have been substituted in the title for bitumens, but bitumens was used, since an abstract of the paper was presented at a meeting where the major emphasis was on bituminous materials. The reader will realize that coals, of which only the more unusual such as the cannel coals and torbanites are discussed in this paper, are primarily mixtures of bituminous materials and carbon. The amount of bituminous material, or volatile matter, in coals is greatest in the lower rank coals and the unusual types described in this paper, and decreases as coal rank increases. However, since no method other than destruction of the original coal substance by heat is known that will separate the volatile matter from the carbon, it appears reasonable to classify the coals with other bituminous materials, particularly since bituminous coal - the most widely used coal - by its name indicates the combination of bituminous materials and carbon.

Jan 1, 1961

By Maria I. De Rosa

The U. S. Bureau of Mines performed experiments to determine if the primary gas toxicities evolved during the early (~300° C) and later (~400° C) combustion stages of chlorinated polyester-reinforced mine ventilation ducts could be predicted by a smoke particle characteristic, for the development of a test parameter. The experiments were conducted in an approximately 20-L furnace, at 14-min durations at set furnace temperatures of 2500 and 1,000° C, with an airflow through the furnace of 10 L/min. The variables studied, as a function of time, were the hydrogen chloride (HCI), carbon monoxide (CO), carbon dioxide (C02), and oxygen (02) concentrations, furnace temperatures, the sample mass weight loss, the average smoke particle diameter (dg and average number and concentration (no), and the product of the average smoke particle diameter and concentration (dgno). Results show that the inverse of the smoke particle diameter-concentration product [(l/dgn0)], correlates directly and significantly with the primary gas toxicities evolved during both early (HCI) and later (CO) stages of combustion.

Jan 1, 1989

By John A. Kost

Control of the dust produced by continuous mining machines in coal mines is conventionally attained by water sprays from fixed nozzles mounted on the frame of the machine behind the cutting head. In the tests conducted under this contract a so-called "wet-head" machine was used, where the spray nozzles were mounted on the rotating head itself, close to the coal-cutting bits. The tests were conducted at the Robena Mine of U.S. Steel Corporation, using Lee-Norse machines. Operating the wet-head machine and a conventional spray machine in turns in the same section, it was found that the wet-head produced approximately 25 percent less respirable dust and 60 percent less total airborne dust than the conventional spray machine. The wet-head also greatly improved the visibility of the cutting bits from the machine operator's position. Several difficulties had to be overcome before any meaningful tests could be conducted, including excessive pressure drops in the piping system and plugging of the nozzles from internal water contamination. The major obstacle, however, was the rotating water seals on the wet-head, which leaked excessively after only a few hours of operation. Only after several changes and plant and laboratory tests was a design found which permitted conducting the underground tests without appreciable water leakage.

Jan 1, 1976

By Nar S. Dalal, Xianglin Shi, Val Vallyathan

"INTRODOCTIONIn an earlier communication 1 from our laboratory it was reported that mechanical crushing of coal and quartz under normal air atmosphere generates of free radicals on the particle surfaces, and that these radicals decay with time, hence pointing to a higher toxicity of fresh dusts in relationship to pneumoconiosis and silicosis. More recently Fubini et al.2 have also reported the detection by electron spin resonance (ESR) of the formation of SiO. and Si-type of radicals from quartz particles crushed under atmospheric conditions. In agreement with earlier ESR studies on single crystals of quartz crushed under high vacuum ( -10-10 torr>3 and subsequent exposure to air,3 and to other gases,4 these radicals were identified2 as being formed by the homolytic cleavage of the Si-0-Si bonds and the reactions of the Si• and SiO- radical with atmosphere. Fubini et al.2 also suggested that these radicals might be involved in the mechanism of the fibrotic action by silica, either by transforming the particle surface into a selective oxidating agent or as an initiator of a sequence of reactions leading to fibrosis. Earlier Gabor and Anca5 bad reported that lipid ·peroxidation caused by free radicals on the silica surface might be involved in the red blood cell membrane damage. Thus far, however, no parallel cytotoxicity, fibrogenicity, and free radica1 studies on a given quartz dust sample have been reported, except for some earlier work from our laboratory.1·6·7 We now present more recent results obtained from parallel cytotoxicity, fibrogenicity, and free radica1 measurements on a freshly made quartz dust. The dust's free radica1 content was measured using ESR spectroscopy while its cytotoxicity potential was estimated via hemolysis. Hemolysis was employed as the toxicity test because it is a widely used method for estimating the potential of a dust for disrupting the cell membrane. 8 The fibrotic potential was followed by measuring the dust-induced lipid peroxidation, using linoleic acid as a model lipid. As discussed below, the results obtained suggest new clues to the mechanism of the quartzrelated cytotoxicity and fibrogenicity. MATERIALS AND METHODSReagentsCrystalline quartz particles with a size range of 0.2-2.5 mm were obtained from the Generic Respirable Dust Technology Center, Pennsylvania State University, University Park, Pennsylvania. These particles were crushed in air to obtain quartz dust samples with particle sizes smaller than 20 microns. We chose to work with a dust with mixed particle sizes, rather than a specific range, as an effort to simulate the mining atmosphere. An agate mortar-pestle arrangement was used for the crushing and grinding because of the close similarity of the structure of agate to that of quartz. Diethylenetriaminepentaacetic acid (DETAPAC) were purchased from Sigma. All other chemica1s were purchased from Fisher or Aldrich.Hemolysls ExperimentsHemolytic activity of silica was measured, following an established procedure,9 as the amount of hemoglobin released from a 2 % suspension of sheep erythrocytes after incubation with 10 mg of silica dust for one hour at 37 °C. The hemoglobin release was estimated via the absorbance at 540 nm using a Gioford spectrophotometer. The procedure was calibrated by substituting the silica dust by a phosphate buffer solution as a negative control (background) and O.S % Triton-X-100 as a positive control (100% hemolysis). The percentage of hemolysis was calculated as follows:"

Jan 1, 1990

By Charles E. Semler

The possible utility of selected compositions in the systems SrO-ZrO2-MgO and SrO-ZrO2-Dolomite for commercial refractory products was confirmed in this study. Specifically the compositions of interest are located in the sub-systems SrZrO3-ZrO2-MgO and SrZrO3-ZrO2-Dolomite. Both sub-systems have regions that are not affected by hydration, but the sub-system SrZrO3-ZrO2-MgO has a larger candidate compositional region. Solid state phase relations were determined for the subject systems over the temperature range 1600°C to 1300°C, with compatibility diagrams presented for each. The systems appear to show good refractory character with no apparent low melting compositions. As the compositions of commercial interest lie mostly in the higher ZrO2 portion of each system, information is presented regarding the firing treatment required to develop stabilized cubic ZrO2. A list of suggestions for further study of these systems, to further delineate the characteristics required for possible commercial utilization, is presented.

Jan 1, 1982

By Carl Fisher

A microseismic roof fall warning system was field tested in Western and Eastern coal mines in the United States to better define the capabilities and limitations of the microseismic method in predicting roof fall Microseismic event and energy type data were obtained and documented for twenty-three coal mine roof falls. Field test results indicate that both the microseismic event and energy methods, as applied in this development effort, have a high probability for successful application in a commercially practical roof fall warning system. Based on the results and experience obtained during field testing, a commercial prototype microseismic roof fall warning system was designed and constructed. Although it was the intent of the program to field test the commercial prototype system, delays in equipment fabrication and contract time limitations did not permit field testing.

Jan 1, 1980

By M. L. Wang, S. R. Short, E. M. Daniloff, E. L. Petsonk, D. M. Mannino, G .. R. Wagner

"Background—It has been suggested that health related job selection is a major cause of the healthy worker effect, and may result in inaccurate estimates of health risks of exposures in the working environment. Improved understanding of self selection, including the role of airway hyperresponsiveness, should improve accuracy in estimating occupational risks.Methods—We evaluated symptoms of the respiratory tract, lung function, occupa¬tional and smoking histories, and airway responsiveness from a cross sectional sur¬vey of 478 underground bituminous coal miners and non-mining controls. Workers with abnormal spirometry were excluded from methacholine testing.Results—Methacholine responsiveness (= 15% decline in forced expiratory volume in one second) was associated in both miners and controls with reduced ventilatory lung function and an increased risk of respiratory symptoms. Miners with the longest duration of work at the coal face had a low prevalence of methacholine responsiveness, compared with miners who had never worked at the coal face (12% v 39%, P < 0.01). Throughout their mining careers, miners who responded to methacholine were consistently less likely to have worked in dusty jobs than miners who did not respond to methacholine.Conclusions—These results provide evidence that workers who are employed in dusty jobs are less likely than their unexposed coworkers to show increased non-specific airway responsiveness, pre-sumably as a result of health related job selection. Surveys of workers in which responsiveness data are unavailable may underestimate the effects of dust exposure on respiratory health."

Dec 1, 1996

By H. Tomlinson

"PURPOSE OF REPORTFatalities from falls of roof and coal are responsible for the death of more than 1,000 miners annually in the bituminous coal mines of the United States or practically one—half of the total fatalities in and about these mines. The men are killed by falls singly or in small groups and little or no publicity is given these accidents as they lack the spectacular features of gas and dust explosions. As a result, the public and even the miners have the impression that accidents from falls of roof and coal are just one of the unavoidable hazards of the coal—mining industry. This belief is not true. Accidents caused by falls can be avoided largely by the application of sound engineering principles, by education, and by proper leadership in the industry, just as gas and dust explosions and accidents caused by explosives have been reduced in recent years.The necessity for studying falls of roof and coal becomes apparent by referring to the following data from a table by Adams and Chenoweth:3"

Jan 1, 1933

By R. S. Warfield

The Kasna Creek copper deposit near Lake Kontrashibuna in the Lake Clark region, Alaska, was the object of an investigative project by the Bureau of Mines during the fall of 1948. Recessed because of inclement weather, it was completed in 1949. This project was a part of the Bureau of Mines program in Alaska for the development of critical and strategic minerals. The ore bodies are contact-replacement deposits in limestone. Mineralization is mainly specular and micaceous hematite associated with chalcopyrite, calcite, chlorite, quartz, and amphibole. The deposit, on the right limit of Kasna Creek approximately 2 miles from the shore of Lake Kontrashibuna, is composed of two mineralized zones that range in altitude from 2,350 to 2,650 feet. This report contains a brief history of the prospect, description of the physical setting of the property, its geology, and the factual results of the Work performed by the Bureau of Mines.

Jan 1, 1951

By Carl Belser

This report is the first of a series dealing with the oil-shale reserves of the Green River formation in the Rocky Mountain Region. The known oil-shale reserves of northwestern Colorado at present considered to have economic value apparently are confined to the Piceanco Creek basin between the Colorado and White Rivers. The number of sampled sections is small, but there can be little doubt that the Piceance Creek basin is a potential source of enormous quantities of liquid fuels and the related byproducts obtained from oil-shale processing. The partly blocked and inferred oil-shale reserves of 25-gallon-a-ton shale are estimated to have an oil yield of 125 billion barrels and the reserves of 15-gallon-a-ton shale are estimated to have an oil yield of 494 billion barrels. The number of available sampled sections is inadequate for making firm estimates.

Jan 1, 1951

By Donald W. Ross

Petroleum oils of widely different grades have long been clarified or decolorized by contact with fuller&apos;s earths. More recently, so-called activated clays have also been used for this purpose. Still more recently ouch clays have been used in the form of nodules termed "catalytic pellets." Clays of varied appearance and from different localities possess the desired bleaching qualities, but evaluation of such clays, so useful to the oil industry, has not been simple. Previous methods of identification and evaluation have largely followed procedures of production methods and were not primarily based upon the fundamental properties of the clays. Thus) a false assumption has grown up that) bleaching clays probably have no common properties on which a-method of comparison can be based. Fuller&apos;s earths and activated clays have a large absorptive capacity for the color constituents of petroleum and its products decolorizing is accomplished by bringing the oil into intimate contact with the clay and later separating the decolorized oil from the clay with its load of absorbed coloring matter. Former practice in absorbing "color" was to use the clay as granules or In&apos; powdered form. More recent practice is to use clay pellets that are more abrasion-resistant than the granules. The oil is either filtered through a bed of clay, percolation method, or agitated on contact with the clay, contact method. Viscous oils are decolorized at an elevated temperature, so that their viscosity is lowered to the point at which thorough contact with the clay is insured. Nonhumidifying, nonoxidizing gas, such as dry steam or dry nitrogen, is used to seal such hot oil masses from the atmosphere.

Jan 1, 1948

By Harry H. Ku

In December 1975, a report entitled "An Evaluation of the Accuracy of the Coal Mine Dust Sampling Program Administered by the Department of Interior" [1] was prepared by the Analytical Chemistry Division of the National Bureau of Standards (NBS), in response to a request by Senator Harrison A. Williams. Chairman, Committee on Labor and Public Welfare. The report attempted to evaluate the adequacy of (1) the personal sampler unit used to measure the coal dust concentration in the mines, (2) the procedures used by the Department of Interior (DOI) to analyze the dust samples obtained from mine operators, and (3) any recent studies made by the Department or private industry concerning the coal dust sampling equipment. Recommendations in the report of NBS included continued research efforts by the appropriate organization to correct the personal sampler deficiencies and to consider the use of area or stationary samplers as a supplement to the personal samplers. Concurrent with the NBS report cited above, the General Accounting Office (GAO) also issued a report in December, 1975 [2], suggesting that improvements are still needed in coal mine dust sampling programs and procedures relating to penalty assessments and collections. Among recommendations made by GAO, the following paragraph specifically called for actions by the agencies involved:

Jan 1, 1979

By M. A. Mahtab

This report presents the geometric parameters (attitude, spacing, extent, and aperture) of fracture patterns in a selected portion (study area) of San Manuel copper mine, Arizona. The geometric parameters are quantified for input to structural analyses for studies of the influence of fractures on cavability of ores. Using an orientation analysis procedure developed earlier by the Bureau, three prominent and nearly orthogonal sets of fracture orientations were delineated in the study area. Sets 1 and 2 dip nearly vertically, and generally strike east-west and north-south, respectively, whereas set 3 is nearly horizontal. Both a horizontal rotation (of 14° to 26° for sets 1 and 2, respectively) and a tilt (of 20° for set 3) is shown to occur between the 1415 and 2015 levels of the mine. Gomparison of the three major rock types present in the study area (quartz monzonite, monzonite porphyry, and rhyolite) show that the rhyolite is characterized by short extent, small spacing, and tightness of fractures as well as the general absence of fracture set 3, which may account for its generally observed strong resistance to caving.

Jan 1, 1973

By O. C. Blade

This report on the properties of aviation gasolines and aviation jet fuels produced in the United States during 1954 was made under a co-operative agreement between the American Petroleum Institute and the Bureau of Mines of the United States Department of the Interior. Analytical data are presented for 101 samples of aviation gasoline. Data also are given for 30 samples of aviation jet fuel. The analyses were made on samples typical of the manufacturers I 1954 production in their laboratories and the results submitted to the Bureau of Mines for compilation. The products of 19 manufacturers of aviation gasolines and of 15 producers of aviation jet fuels are represented.

Jan 1, 1955

By Arel B. McMahan

The U.S. Bureau of Mines investigated mines, prospects, and mineralized areas in the Owlshead Mountains Wilderness Study Area (WSA) in 1982. Within the WSA, subeconomic manganese, iron, zinc, and lead resources were identified at two mines; sample analyses indicate five other mines and prospects may have gold, silver, iron, manganese, and copper resources. Three mines examined adjacent to the WSA have identified manganese and iron resources; and sample analyses indicate manganese, iron, and gypsum resources may exist at two prospects. Greatest likelihood for future identification of mineral reserves is for manganese at the Black Magic Mine in the southeast part of the WSA. The southern half of the WSA contains nearly all identified mineral resources, and properties at which sample analyses indicate additional resources. The most significant are manganese and iron resources at the Black Magic Mine in the southeastern part of the WSA; and the Ellie, New Deal, and Owl Hole Mines adjacent to that part of the area. Manganese and iron minerals filled fractures and replaced limestone in brecciated and faulted contacts with intrusive granitic rocks. In the southwest corner of the WSA, sample analyses indicate four prospects may have gold and silver resources. These precious metals are in gouge zones along contacts where diorite has intruded volcanic rocks. A small identified resource at the Kennedy Boys Lead Mine in the western part of the WSA consists of quartz veins with zinc and lead minerals along a brecciated contact between granite and limestone roof pendants.

Jan 1, 1985

By Paul Hatmaker

This paper covers briefly the particular field of dolomite and magnesium limestone; certain uses of high-calcium limestone are mentioned only to show more clearly the limita¬ tions of the magnesian rocks. Such a comparison is helpful because magnesium carbonate is essential for some uses; for others it is immaterial; and for many its presence in an appreciable amount is objectionable. Magnesium carbonate, occurring as a rock resembling limestone or dolomite, is described in United States Bureau of Mines Information Circular 6437, Magnesite. Other com¬ pounds of magnesium are described in United States Bureau of Mines Information Circular 6406, Magnesium Compounds (Other Than Magnesite). Limestone, geologically, is a rock composed essentially of calcium carbonate; commercially, however, the term may include dolomite and magnesium limestone.

Sep 1, 1931

By Roger L. Williams

The Bureau of Mines investigated northern New Jersey as a potential future source of yttrium and the rare-earth elements. The studies, consisting of geophysical surveying, sampling, and exploratory drilling, began in the spring of 1959. A total of three and one-half months were spent in the field collecting data. Thirty-three deposits were investigated, of which five demonstrated some potential resources of yttrium and rare-earth minerals. Results indicate that the deposits examined do not contain quantities of yttrium and the rare-earth elements recoverable under present economic conditions. Detailed studies conducted at the Scrub Oaks mine, near Dover, N. J., delineated a yttrium and rare-earth-bearing zone within the magnetite-hematite ore body that represents a potential low-grade deposit. Beneficiation studies on this deposit indicate that a final product, averaging 31.3 percent rare-earth oxides including yttrium, could be produced through amine and fatty acid flotation procedures with 77 percent recovery. Two hundred and eighty-five feet of diamond drill core was obtained from exploration studies conducted at the Bemco prospect in Sussex County. The deposit averages 2.30 percent rare-earth oxides (including yttrium), 0.45 percent uranium and 0.24 percent thorium. Low-grade deposits were identified at the Canfield phosphat2 mine and the Tanners Brook Monazite placers in Morris County, and the Marble Mountain prospect in Warren County.

Jan 1, 1967

By John C. Edwards

The Bureau of Mines developed a mathematical model to predict the oxygen requirements for a miner evacuating a mine. The model accounts for variations in the miner&apos;s escape speed with mine airway height, and for the empirically determined expressions for the weight-specific oxygen uptake rate for upright walking, stooped walking (duck-walking), and crawling. A Fortran computer program that is user oriented was prepared based upon the model&apos;s constitutive equations. Specific instructions for utilizing the program, as well as applications to miner evacuation from a mine, are presented.

Jan 1, 1986