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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. J. Morrell

The Bureau of Mines conducted a series of laboratory experiments to test a cutting technique for hard rock using large-scale drag cutters. Cutting experiments were performed on rocks ranging in compressive strength from 10,000 to 27,000 Ib/in2, using large drag cutters from 3 to 6 in. in width. The tests were conducted on a special test apparatus, called a ripper tester, which made a curvilinear cut across the rock sample while measuring the cutting force acting on the drag cutter. The cutting method that evolved from these experiments is called ripper cutting, and its energy efficiency appears superior to all other large-scale mechanical fragmentation techniques. In addition, the method cre-ated very little dust, and the wear on the bits was negligible. A fragmentation system based on ripper cutting was then devised, and a large-scale test device was fabricated to allow full-scale laboratory testing of the system. The results of these tests will be published in future Bureau reports.

Jan 1, 1986

By O. C. Blade

A summary of the characteristics of motor gasoline for the winter 1951-52 is presented in table I, and for comparison, a similar summary for the winter 1950-51 is shown in table 2. Trends of some of the more important characteristics over a period of years are shown in figures 1 and 2. The results of this survey show that octane numbers have risen slightly since the summer of 1951 but are below the record levels of the winter of 1950-51. The fractions of a unit change since the summer preceding have resulted in the research and motor-method octane values being virtually the same as the figures for the survey of summer 1950. In volatility characteristics the winter gasolines have changed very little. Average Reid vapor pressures are 10.5 pounds for both grades of fuel compared to 10.4 and 10.5 pounds for premium and regular-price gasolines, respectively, of the winter of 1950-51.

Jan 1, 1952

The following is a Maintainability Design Checklist for coal mining equipment. The purpose of the checklist is to provide a summary of design review points for the maintainability assessment of new or existing underground equipment. It specifically focuses on the identification of equipment design features, tasks, or procedures that impact equipment downtime, repair costs, labor hours and maintainer skill level requirements. Some checklist points are general in nature. The checklist was designed to be used across all categories of underground equipment. The intent is to draw attention to design features and maintenance procedures that will increase maintainability requirements. You are encouraged to adapt this checklist to site specific or machine specific requirements by: ? Inserting specific performance criteria for various categories of maintenance tasks. For example; all hydraulic lines on a shuttle car should be replaceable in 15 minutes or 25 minutes, etc. ? Adding or deleting checklist items for different categories of equipment. You would include environmental control equipment, for example, on face equipment and not on shuttle cars or man trips. ? Adding additional checklist items based on site or equipment specific maintenance histories or experience, company maintenance standards, or other factors.

Jan 1, 2000

By Fred D. DeVaney

Copper sulphate is a common flotation reagent for blonde ores. Metallic iron also is present in the mill circuit, and a reaction between the iron and the salt would be in accord with well-known chemistry. The abundance of metallic iron in a flotation food may be noted by even perfunctory examination. First of all the mine contributes metallic iron, then the coarse-crushing machines add their share, and finally the fine-grinding medium its portion. If the grinding is with cast-iron balls the amount of metallics is greater than when steel is used. Thus it, is that much more metallic iron is present than would be indicated by noting the ball consumption. An estimate that the total amount of metallics is twice that supplied by the balls and liners might not be far amiss. That copper sulphate plates out on iron in an acid solution is well known, but since flotation is practiced commonly in solutions where acid has not been added this reaction has not been given sufficient thought.

Jan 1, 1929

By L. M. Demers, D. C. Kuhn

"Kuhn, Douglas C., and Laurence M. Demers. Effect of surfactant on basal and silica-induced eicosanoid production by the alveolar macrophage. Am. J . Physiol. 269 (Lung Cell. Mol. Physiol. 13): L165-Ll 70, 1995.-Infiammation and fibrosis subsequent to the inhalation of certain mineral dust particles has been suggested to result from the activation of eicosanoid synthesis by the alveolar macrophage (AM). To determine if surfactant modifies dust-induced generation of eicosanoids by the AM, we evaluated the effect of the surfactant lipid dipalmitoyl lecithin (DPL) on the production of eicosanoids by rat AM exposed to respirable silica dust in vitro. During the first 24-h exposure period, DPL alone significantly increased basal production of eicosanoids but completely inhibited silica-induced thromboxane A2 synthesis. In contrast, leukotriene B4 (LTB4 ) production was only partially reduced by DPL. During a second 24-h exposure period, LTB4 production in response to the highest dose of silica remained significantly elevated in the presence of DPL. Similar results were obtained when the surfactant preparation Survanta was evaluated. These results suggest that 1 ) DPL and Survanta independently activate AM eicosanoid production, 2) DPL and Survanta modulate the response of the AM to silica dust, and 3) L TB4 may be the most important eicosanoid mediator of the long-term effects of silica dust exposure on lung pathophysiology. THE OXYGENATED METABOLITES of arachidonic acid (AA) (here collectively termed eicosanoids) have been implicated as important regulators of lung physiology and are thought to be involved in pathophysiological sequelae such as acute respiratory distress syndrome, asthma, and the pulmonary complications of sepsis (20). This role is manifested through both direct effects on lung physiology as well as through an indirect modulatory effect on the release of other mediators of lung injury, in particular profibrotic cytokines such as the interleukins and tumor necrosis factor (15). Recently, exaggerated eicosanoid production by both the alveolar macrophage (AM) and the type II epithelial cell has been demonstrated to result from the exposure of these cells to several particulates, including crystalline silica (quartz) dust (5, 9, 17). These observations have led to the suggestion that eicosanoids play a major role in the etiology of pneumoconioses.Another secretory component of the pulmonary environment, surfactant, has been shown to modulate crucial AM functions, such as bactericidal activity and the recruitment of circulating immune cells (25). Indeed, an important feature of the lung's reaction to inhaled mineral dust is an increase in surfactant production, perhaps as a compensatory or protective response (1, 16). In addition, the alteration of the surface properties of mineral dust by surfactant or its components has been shown to influence the biochemical response of the AM to the dust, perhaps by altering the surface charge of the dust particle (11, 29, 32). And recently, Wallace et al. (28) have shown that the coating of mineral dust with surfactant, and its subsequent removal by lysosomal phospholipase, unmasks differences in dust cytotoxicity that are not apparent when AM are exposed to uncoated dust. Thus it appears that the inclusion of surfactant in in vitro exposure studies may be important in evaluating both the absolute levels of eicosanoid production by the normal and dust-exposed AM and the temporal relationship between dust exposure and the production of inflammatory mediators by the AM. Therefore, we characterized the effects of the surfactants dipalmitoyl lecithin (DPL; the primary lipid component of natural surfactant) and Survanta (a commercially available surfactant derived from bovine lung) on basal and silica-induced AM eicosanoid production during two 24-h periods after exposure to dust particles to both allow the enzymatic removal of surfactant from the particle surface and evaluate the k"

Dec 1, 1996

By G. S. Scott, G. W. Jones

"INTRODUCTION An important phase of the accident-preventing program of the Bureau Mines is the determination of the explosion hazards of various combustible gases, vapors, and liquids encountered in mining and allied industries and the development of methods of eliminating or mitigating them.Recently, isobutane has become a commercially important raw material in the production of aviation gasoline by the alkylation process. 4/ in which isoparaffins are combined with olefins to give higher molecular weight compounds of branched-chain structure.Because of the anticipated commercial importance of isobutane in industry, it has been deemed necessary to study and determine its general explosion haz¬ards. This report gives its limits of inflammability, minimum ignition temper¬atures, and the amounts of nitrogen and carbon dioxide required to render isobutane-air mixtures noninflammable."

Jun 1, 1947

By G. H. Keith

Oxygen and nitrogen cause strain aging in electrorefined vanadium, as evidenced by maxima in yield and tensile strengths and by Snoek internal friction peaks. Alloys containing up to 0.22 percent oxygen and 0.11 percent nitrogen were investigated. Tensile strengths of oxygen-and nitrogen-containing alloys were 66,000 and 68,000 psi at 300° to 400° C, compared with 53,000 and 62,000 psi, respectively, at room temperature. Total elongation decreases to about 7 percent at the temperature of maximum strength. At 600° C, strain aging is not evident. Based on interstitial contents calculated from internal friction measurement, the increases in strength caused by nitrogen and oxygen were 440,000 psi per weight-percent nitrogen and 260,000 psi per weight-percent oxygen. Application of the Schoeck and Seeger treatment to the Snoek effect in these systems results in a calculated lattice distortion of 0.24 and 0.15 caused by the presence of an interstitial nitrogen or oxygen atom, respectively. Alloys containing boron or carbon were also investigated. Both elements refine the grain size but have no other effect because of their low solubility in vanadium.

Jan 1, 1969

By F. D. Everett

The exploration work on a seleniferous tuff deposit near Lysite, Wyo., was confined chiefly to an area of approximately 1 square mile selected on the basis of prior examination and sampling work by the Bureau of Mines. This area was superficially explored by digging and sampling over 2,000 feet of trenches and 15 test pits. The surface sampling indicated that the deposit might contain a multimillion-ton reserve of easy-to-mine volcanic tuff assaying more than 0.01 percent Se. Later, 11 holes, ranging in depth from 57 to 135 feet and totaling 929.4 feet, were drilled under contract using a dry rotary drill. Samples for assay were cut at 5-foot intervals or at noticeable physical changes in the formation being drilled. Of the 206 samples assayed from the drilling, only 8 contained more than 0.005 percent selenium, and 2 of these assayed as high as 0.012 percent Se. Chemical analyses of samples obtained from six holes drilled by the Nugget Coal & Timber Co. to the south of the area explored by the Bureau of Mines showed that no selenium-bearing formations were encountered in that work. Two of 72 samples taken from 42 validation pits dug by claim holders contained more than 0.005 percent selenium. The exploratory work established that the selenium mineralization is erratically distributed in small irregular bodies and is not confined to any one tuff bed. Because of the lack of correlation between the infrequent showing of low-grade tuff, neither the extent nor grade of the reserves could be calculated.

Jan 1, 1957

To provide longwall operators with a method to predict methane emissions from panels with increased face width.

Jan 1, 1997

By Stephen Krickovic, J. E. Carpetta, T. D. Moore

Air quantity-pressure and methane concentration surveys were conducted by the Bureau of Mines in accessible portions of an area being pillared in a Pittsburgh coalbed mine in West Virginia. These included two mined-out and three active butt headings and a bleeder system. The particular mine workings were started in virgin coal directly from a set of main headings; the main reason for the study was the difficulty usually encountered in adequately bleeding the gobs under such conditions. Although the two separate return airways in each active butt heading and the North and 1 Left bleeders contained acceptable methane concentrations (0.01 to 0.78 percent in the butts and 0.73 to 1.0 percent in the bleeders) with significant total methane removal (109 cfm in butts and 631 cfm in bleeders), there were relatively large areas in the gobs with possible minimal airflows. This condition appears to have developed from lack of systematic regulation of the airflow across the gobs and appears to indicate the existence of considerably more methane in the probably low flow areas in the gob.

Jan 1, 1973

By L. H. Duschak

"This paper is based on the results of work conducted of the bureau's experiment station at Berkeley, Calif., in connection with the investigation of properties and methods of utilizing Western magnesite. The experiments described herein were made under the supervision of the writer, by W. C. Riddell and E. H. Delius, of the station's staff.In calcining magnesite for the production of magnesium oxide to be used in the preparation of oxychloride cement, the calcium carbonate present in the original rock may remain unchanged or appear in the finished product, either as CaO, or in combination with SiO2, A12O3, etc. As there is reason to believe that free CaO may have an effect on the behavior of caustic magnesia in the cement reaction, it is desirable to have a method for the determination of the relatively small amounts of free CO in the presence of a large quantity of MgO.The extraction of the free CaO with water free from CO2 at once suggests itself as a possible method. The solubilities of Ca(OH2)2 and Mg(OH)2. are given by Seidell in his book an ""Solubility of Inorganic and Organic Compounds."" (2nd Edition, 1919) as follows:"

Jun 1, 1920

By L. A. Grant

This paper describing the concentrator practice of the Montana Mines Corporation at Helena. Mont., is one of a series of articles on milling methods and costs being prepared by the United States Bureau of Mines. The Spring Hill mine and mill are located 4 miles south and west of Helena, Mont., near the head of Grizzly Gulch. The mine portal is on the east slope of the gulch, and the mill is directly opposite on the west slope. Grizzly Gulch is one of the tyro gulches which unite at the south end of Helena to form Last Chance Gulch, on which the main street of Helena is built.

Jan 1, 1931

This report summarizes the cost of U.S, mining and milling industry compliance with the Environmental Protection Agency (EPA) interim water quality guidelines for waste discharges. Applicable excerpts from Public Law 92-500 are stated and interpreted in conjunction with the guidelines being used for implementation of the law. Over 200 U.S. Army Corps of Engineers applications for discharge permits were used to develop the quality and quantity data base needed to estimate the cost to comply with EPA guidelines, Cost of three basic treatment methods were considered: Aeration, addition of lime, and sedimentation. From the process design, cost-capacity graphs were developed to consider maximum flow rate, maxi lime addition, and average flow rates. The graphical method used in this evaluation should provide a reasonable guide to the effect of waste treatment and, therefore, Public Law 92-500 and corresponding EPA guidelines on the mineral processing industry. The cost of complying with the EPA guidelines will have the effect of prompting the mining industry to minimize the production of waste water and of undertaking some additional treatment, Two case studies are presented to illustrate efforts that might be fruitful for minimizing waste water production and for treatment of combinations of acid mine drainage, mill wastes, and metallurgical process wastes when treatment is deemed necessary.

Jan 1, 1975

By Christopher J. Bise

Volume II of this collection of research reports, entitled "Model Training Program," provides the framework and details for developing a tailored training program for a specific mine based upon documented human-performance deficiencies. To do this, several steps must be followed prior to program implementation: 1) background information must be gathered (database analysis), 2) direct observation of indicated problem areas should be conducted (safety sampling), and 3) separation of those deficiencies to be addressed through training from those which would be better addressed by workplace or equipment redesign (trainability assessment). Once training is determined to be the appropriate strategy for addressing the noted deficiencies, several approaches can be taken, depending upon whether the problem is related to repetitive work procedures in a predictable, a variable, or a dynamic workplace with a substantial amount of interaction between workers, equipment, and the environment. Although this volume and the subsequent seven volumes provide examples of how the training information was field tested using various strategies (for example, loss control, task training, etc.) and techniques (for example, microcomputer-based exercises, lectures, etc.), the ultimate selection of the delivery method is based on cost/benefit analysis. Therefore, the Model Training Program has incorporated a Training Cost Model as a desirable component.

Jan 1, 1993

By Charles W. Merrill

The U .S. Treasury stocks of silver have been reduced at such a rapid rate to meet industrial and coinage requirements that they face exhaustion in 3 or 4 years. Alleviation of the silver problem will require increasing supply or reducing demand. This paper examines possible long-range resource development and research programs and improved secondary recovery. The possible reduction or elimination of silver in coinage and development and introduction of substitutes in the arts and industry are also discussed.

Jan 1, 1965

By Kenneth M. Smith

The kaolin deposits of Aiken County, South Carolina (fig. 1), have been worked continuously since 1852. It has been long known that the deposits contain a high percentage of' alumina and that large reserves exist. These facts led to the early selection of' this area for examination in the search by the Bureau of Mines for high-alumina clays. An exploratory program was started by the Bureau, and drilling was carried on from. June 27, 1942, to October 31, 1942. The kaolin-bearing district occupies an area approximately 25 miles long and 11 miles wide, running northeast, with its center at Aiken, S. C. (fig. 1). Within this district, a triangular area bounded by Horse Creek, Silver Bluff Road, and Hamburg Road was roughly prospected by boring 43 machine and 12 hand holes. As a result of the data obtained, a final smaller area was chosen for more systematic prospecting. This area is bounded by Pine Log, Tewkesbury, Silver Bluff, and Craig Sawmill Roads and covers about 4,000 acres. Mineral exploration agreements covering 11,272 acres were signed by 35 property owners, and 11,956 feet was drilled in 200 holes on these properties.

Jan 1, 1949

By Lowell B. Moon

Regardless of how a mineral deposit in first discovered or by whom, any mining enterprise based upon it must pass through a preliminary stage of exploration. The common understanding of ?exploration? among mining engineers is well-expressed by Jackson and Knaebel:3/ Exploration work ranges from that performed by the individual prospector employing only the simplest tool, and equipment to elaborate campaigns involving the expenditure of largo stuns of money end the use of churn- car diamond-drilling equipment, large test-pitting crews, or sometimes a regular mining organization. In any event, the object is to determine as accurately as possible, with the funds available, the size, shape, and other characteristics of the ore bodies and their average value or grade.

Jan 1, 1945

By Charles W. Merrill

The U.S. Treasury stocks of silver have been reduced at such a rapid rate to meet industrial and coinage requirements that they face exhaustion in 3 or 4 years. Alleviation of the silver problem will require increasing supply or reducing demand. This paper examines possible long-range resource development and research programs and improved secondary recovery. The possible reduction or elimination of silver in coinage and development and introduction of substitutes in the arts and industry are also discussed.

Jan 1, 1965

Confidence in the strength of the U.S. economic recovery was considerably enhanced by third quarter 1983 profits, which showed a 12.8-percent increase over those in the second quarter (table I). Although the increases were not as great as between the first and second quarter of 1983, profits have grown each quarter since fourth quarter 1982. Both total profits and profits per unit of output increased, which the Bureau of Economic Analysis (BEA) attributes to decreases in labor and nonlabor costs (per unit of output), as well as to moderate price increases. [ ] A number of durable goods sectors, however, continue to show profit declines, especially electrical and non-electrical machinery. Profits in the primary metal industry are still negative, but the economic picture of this industry is improving. Between the second and third quarters of 1983, capacity utilization increased somewhat in primary metal manufacturing and stone and earth mineral mining but did not change at all in metal mining. Capacity utilization in metal materials increased from 47.4 percent in the fourth quarter of 1982 to 64.2 percent in the third quarter of 1983 (table 2).

Jan 1, 1983