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By Irving Hartmann

The Bureau of Minas has been charged by the Congress with the responsibility for administrating the provisions of the Federal Coal-Mine Safety Act. One of the important duties of bureau inspectors under this act is to determine whether proper measures are taken to prevent mine explosions, which in moat miner includes Judea adequate rock dusting The investigation made after the explosion in Orient No. 2 mine, December 21, 1951, showed that much information is lacking on the adequacy of current rock-dusting and duet-sampling practices in the United States. To obtain such information, an intensive sampling survey was conducted by the Bureau in an Indiana coal mine. This paper summarizes the more Important findings from this survey, describes special samplings at several Pennsylvania coal miners, and discusses related studies in the Bureau's Experimental coal mine.

Jan 1, 1954

On December 16, the General Services Administration (GSA) suspended weekly sales of surplus silver from the national defense stockpile because Congress approved the Defense Appropriation Act, which contained an amendment to halt silver sales. The amendment, introduced by Senator James A. McClure (R., Idaho), prohibits sales for 6 months while the impact of the sales and alternative methods of disposal are evaluated. The GSA sold 2 million troy ounces since sales started October 14. 46.5 million troy ounces were authorized to be sold during this fiscal year and an additional 58.6 million troy ounces were authorized to be sold over the following two fiscal years. The stockpile held 139.5 million troy ounces of silver when sales began in October. Brush Wellman, Inc., a vertically integrated producer of beryllium products announced plans to modify its Delta, Utah beryllium concentrate processing facility to utilize beryllium concentrates containing as little as 7% beryllium oxide. The company plans to invest $2.5 million for this modification with completion expected in mid-1983. Implementation of this plan to consume lower grade beryllium minerals will significantly increase world reserves of beryllium concentrates.

Jan 1, 1981

By Robert A. Speirer, Richard G. Burdick

Methods of detecting geologic faults and other linear features by means of processed LANDSAT satellite images have gained prominence during the past several years . There have been numerous programs written to pick these " lineaments , " but they have been almost universally tailored to large computers . This Bureau of Mines report describes a detection method developed for use with a minicomputer . The method comprises a suite of programs that scans an image for all " potential " lineaments . From this partially analyzed data , the final lineaments are picked by another routine . The method was field tested in an area of south- central Wyoming , and results indicated good agreement between computer- picked lineaments and ground features . Most of the known geologic faults in the area were picked by the method . Such features as roads and trails were also picked but were easily distinguished from faults during field inspection . The method is relatively new but promises to be a viable reconnaissance technique for the mining industry in geologic structural analysis .

Jan 1, 1965

By R. T. Sorensen

Bench-scale and continuous testing were performed to adapt the anionic process for flotation of calcium activated silica to the fine-grained hematitic-goethitic jaspers from the Marquette range, Michigan. These ores typically contain about 35 percent Fe and require grinding to about 80 to 100 percent minus 400 mesh to insure an adequate liberation of gangue from the iron oxides. A method for removal of troublesome slime fractions without excessive iron loss, by first dispersing the quartz and then selectively flocculating the iron oxides, was evolved in the laboratory and successfully accommodated to pilot plant practice. The efficiency of the flotation process was improved with respect to both reagent usage and concentrate grade and recovery by using the selective flocculation-desliming technique as a pretreatment. The benefits of the combined desliming-flotation procedure were most evident in pilot plant processing. The best tests on two ores yielded recoveries of about 84 percent in concentrates containing 65.1 percent Fe and 4.8 percent SiO2 and 66.2 percent Fe and 3.9 percent SiO2, respectively. These results are in comparison to recoveries about 10 percent lower than the above to concentrates containing 63.9 percent Fe and 6.6 percent SiO2 in the one instance, and 63.6 percent Fe and 7.2 percent SiO2 in the other, obtained by flotation without the prior desliming treatment.

Jan 1, 1967

By R. Clark Lantz, Charles Stanley, David E. Hinton

Morphometric examination of lung alterations following exposure to toxic and pathogenic substances is invaluable in detecting subtle changes which might otherwise be overlooked. Results, from evaluation of initial structural alterations, support and guide subsequent nonmorphological techniques and, when coupled appropriately, can lead to a better understanding of the pathogenesis of a disease. Morphometry is a technique which can be used to determine, quantitatively, the site, extent, development, and progression of a disease state. Determination of the extent of tissue and cellular involvement in the response to inhalation of silica has been performed in order to gain a better understanding of the development of fibrosis following inhalation of this toxicant. In addition, since silica has been postulated as one of the important pathogenic minerals in coal mine dust' it is important to understand the lung tissue response to silica prior to evaluating the effects of inhaled coal mine dusts. Male Syrian golden hamsters were placed in Hazelton 1000 inhalation chambers and were exposed to either filtered air (controls, n = 24) or filtered air plus 30 mg!m3 silica (Min-U-Si110,95%ofparticles < 5 um,n =24)for16hours per day, five days per week, for two weeks. Animals were returned to the animal quarters prior to subsequent tissue processing at 1, 4, and 12 weeks following exposure. This schedule was designed to allow time for the development of fibrosis. Lungs were fixed by intratracheal perfusion of ½ strength Karnovsky's fixative at a pressure of 20 cm H20 and tissues were taken for embedment and analysis at the light level. Determination of site, extent, and development of alterations was performed using a multitiered approach. Changes in large structures (airways, blood vessels) was determined prior to evaluation of changes at the septal tissue level. Data will be presented outlining the progression of changes. Results indicate the usefulness of morphometric analysis of lungs following inhalation of toxic substances in quantitatively defining the structural alterations.

Mar 1, 1989

By Keith L. Harris

Real gross national product3 (GNP) grew at a seasonally adjusted annual rate of 4.2% in the fourth quarter compared with a revised 4.3% rate in the third quarter, according to the most recent estimates released by the U.S. Department of Commerce (table 1). Expanding inventories, Government purchases of goods and services, residential fixed investment, and a narrowing of the trade deficit fueled the growth. Significantly reduced consumer demand led to the heavy inventory growth. Almost half of the buildup in inventories consisted of automobiles because consumers reduced purchases when Detroit ceased most incentive programs in late summer. Reduced consumer demand also affected imports, however, and the narrowing of the trade deficit resumed after widening in the third quarter. Nonresi- [ ] dential fixed investment also declined after a strong gain in the third quarter. On a year-to-year basis, the economy grew at an inflation-adjusted rate of 2.9%, the same as that of 1986. However, on a fourth-quarter-to-fourth-quarter basis, the real growth reached 3.8%, the highest growth since 19M, and exceeded the Reagan Administration&apos;s estimate of 3.4%. Rising merchandise exports accounted for about one-third of the growth in GNP for all of 1987 and are expected to continue to grow as domestic manufactures benefit from the lower value of the dollar vis-a-vis other major trading country currencies. Consumer demand became a less important factor of economic growth, but employment continued to grow (table 2), and civilian unemployment declined by 0.9 percentage points (December to December) as the industrial sector geared up to increase exports. Inflation, as measured by the fixed-weighted GNP price index, remained low at 3.4%.

Jan 1, 1988

By J. Burlin Johnson

In small-scale blasting experiments conducted in the Bureau of Mines laboratory, small charges were used to produce craters in blocks of concrete mortar. The results are compared with larger scale experiments of other research workers, and the comparison demonstrates the similarity of the results obtained and indicates that small-scale blasting should be a useful tool for predicting large-scale blasting effects. INTRODUCTION The purpose at this investigation was to conduct blasting experiments in mortar in the laboratory and then, by comparing the results with those from larger scale field blasts in rock to determine to what extent, if any, the laboratory results resemble those in the field. The work described herein was the initial phase of a project aimed at evaluating small-scale blasting as a tool for use in improving blasting techniques. It is evident from the stand-point of control and cost that small-scale blasting would be valuable in the study of rock fragmentation by blasting in mines and quarries, if the extrapolation is valid.

Jan 1, 1962

By E. A. Loria

High-quality sheet of electrowon molybdenum was attained by a sequence of procedure on pressed and arc-melted crystalline powders. The procedures included high-temperature, high-vacuum sintering treatments and the use of metal deoxidizers instead of carbon to improve the mechanical properties of the molybdenum sheet. Rolled sheet 60 mils thick was evaluated by tensile and bend tests, hardness measurements, microstructures, and recrystallization treatments. After stress relieving, yield strength ranged from 85,000 to 110,500 psi (0.2- percent offset) and ultimate strength ranged from 87,200 to 117,250 psi with 4.5- to 25-percent elongation observed for arc-melted sheet, and 5.0- to 23- percent elongation observed for powder metallurgy sheet. In room temperature bend tests the sheet yielded plastically, indicating that the ductile-brittle transition point was below room temperature. The diamond pyramid hardness (DPH) of the molybdenum sheet changed from 214 to 293 DPH for the stress-relieved condition to 177 to 185 DPH for the fully recrystallized condition. The brittleness of recrystallized molybdenum, reported by other investigators as characteristic of sheet prepared from commercial-grade hydrogen-reduced powders, was not in evidence. Recrystallized tensile specimens pulled at room temperature had an average elongation of 31 percent.

Jan 1, 1966

By H. B. Brunot, Ilsley. L. C., E. J. Gleim

"INTRODUCTION One of the various phases of the work by the U.S. Bureau of Mines, in its endeavors to minimize the hazards that attend coal mining, is the investigation of electrical motor-driven machinery. The object of this investigation is to foster the development of explosion-proof machines for use in gassy mines. This investigation is conducted under the provisions of Schedule 2C, which prescribes the inspection and tests made upon motors, controllers, and other electrical parts to determine their ability to withstand internal explosion without discharge of any flames. The method of conducting these inspections and tests is described in Bureau of Mines Bulletin 305, Inspection and Testing of Mine-Type Electrical Equipment for Permissibility, published in 1929. Formal approval of a machine for use in gassy mines is not granted by the Bureau of Mines until the machine is found to comply with the requirements, including inspection and test. When it is approved it is entitled to classification as a ""permissible"" machine.The high regard in which machines approved by the U.S. Bureau of Mines are held by engineers of other countries is attested by the growing number of shipments of permissible equipment; to other nations, including Australia, Russia, Norway, Japan, and Manchuria."

Aug 1, 1936

By Raymond B. Ladoo

Deposits of talc are known in many districts in Canada but at the present time active mining operations are reported only in Ontario . Here three companies are now operating, two of which, George H. Gillespie & Co. , Ltd. , and the Anglo- American Talc Co. , are at Madoc . The operations of the former company are probably the largest and best known in Canada . The writer , in his capacity as an engineer of the U. S. Bureau of Mines , was permitted by this company to make an inspection of its mine and mill in June, 1920 , and study the methods employed . This information was desired for comparison with methods employed in the United States . The following description is based on observation made during this visit , supplemented by data supplied by the company .

Sep 1, 1920

By Henry E. Blake

Defluorination studies on refractory fluoride - bearing compounds and minerals , particularly on partly defluorinated residues from high - temperature pyrohydrolysis , required a dependable and reasonably accurate analyticalcontrol method for the analysis of fluorine . The difficulty in liberating fluorine from the fluorides of metallic elements such as aluminum, zirconium , and rare earths by steam- distillation can be largely overcome if the distillation is made from a sulfuric - phosphoric acid solution of a sodium carbonate fusion of the sample material and if the distillation temperature is maintained at about 155 ° C. The data presented in this paper show that liberation of fluorine by this method is more complete and proceeds more rapidly than by usual distillations from perchloric or sulfuric acid alone or a mixture of phosphoric and perchloric acids . Fluorine in amounts ranging up to about 140 mg can be recovered by collecting only about 300 ml of distillate . Determination of fluoride in the distillate is made by the usual thorium nitrate titration .

Jan 1, 1963

By M. R. Geer

The use of the cyclone as a dense-medium cleaning device was first described by Driessen6/ in 1945, after development of the process in the Netherlands during the German occupation of World War II. A pilot plant was built in the Netherlands soon thereafter, and the first commercial plant was built in 1948. By 1958, 18 plants were operating or under construction.7/ Thus, economic factors in Europe, where the high cost of coal places a premium on efficient cleaning, dictated rapid adoption of the cyclone. American reception of the process differed. The Bureau of Mines presented the results of its own small-scale cyclone experiments in 1946;8/ showing a sharp separation between coal and impurity; adoption by industry now is taking place. There is now much greater emphasis on the efficient cleaning of fine coal, and the first American cyclone plant has begun operating; others are planned or under construction. With the present interest in improved treatment of fine coal, the Bureau of Mines felt that additional performance data on the cyclone would be helpful to industry. Therefore, a complete, open-circuit pilot plant was built to make cleaning trials on American coals covering a wide range of washability characteristics. Five raw coals and one middling product were included in the investigation, and each was cleaned at several densities; 17 cleaning trials are reported.

Jan 1, 1961

By P. M. Sullivan

At its College Park Metallurgy Research Center in Maryland, the Bureau of Mines has installed and is operating a 5-ton-per-hour pilot plant for continuous mechanical separation of values contained in raw urban refuse. The entire sys tern was assembled using commercially available equipment. The process relies on multistage processing including shredding, air classification, screening, gravity concentration, and electrostatic separation. Compactor trucks deliver raw refuse collected along typical routes in metropolitan Washington, D.C., to the pilot plant. The loads are separated into concentrates of (1) light-gage iron, (2) massive metals, (3) glass, (4) putrescibles and waste combustibles, (5) paper, and (6) plastics. While some refinements remain to be made in the processing system flow-sheet, the data obtained to date have been highly encouraging, indicating favorable economics for commercial-size plants.

Jan 1, 1973

By L. T. MCELVENNY, Robert B. McElwaine, M. Clair Smith

Production of mercury from the cinnabar deposits of the southwestern Arkansas mercury district began in 1931 , reached its peak in 1942 , and ended in 1944. The mines are now idle . Virtually all the cinnabar was obtained from deposits in a belt , about a mile wide , of steeply dipping sandstone beds in the overriding blocks of three thrust faults . The belt was productive for a length of about 27 miles eastward from eastern Howard County, through Pike County, into Clark County . During the early life of the district, Federal agencies watched and recorded its progress as a contributor of a strategic metal, and later, during the war, conducted investigations designed to advance its development . In 1941 , the Bureau of Mines and the U. S. Geological Survey cooperated in investigations on eight mineralized areas in the western part of the district , to wit : Hales mine , U. S. mine , Lulu Bell property, Hopkins Hill , East Gap Ridge , Gap Ridge , Parnell Hill , and Section 17 mine area . U. S. Geological Survey prepared both surface and mine maps and designated the areas to be investigated ; the Bureau did the drilling , trenching, and sampling involved in the investigations . Twelve holes , aggregating 3,539 feet of bore , were diamond drilled on six properties ; 5,309 linear feet of surface trenches were bulldozed in six areas and 19 samples taken from them ; and 86 underground channel samples were cut in two adits on one property . In 1944 , the Bureau of Mines measured mine dumps and calcine dumps in the district in an investigation of their mercury content . Two mine dumps and one calcine dump were sampled . The data pertinent to the work done by the Bureau are included in this report .

Oct 1, 1950

By E. P. Youngman

Gold and precious stones were mined in Egypt in prehistoric times. This mining, carried on at intervals, extended over thousands of years, until about 1300 A. D. Then ensued a dormant period of several hundred yoars. In the mean- time Europe made great rogress in mining practice, metallurgy, and geology and sent out various expeditions during the nineteenth century to investigate ancient mines. But the exploratory work produced no material results, and not until the beginning of the present century did actual mining recommence. The reopening of old gold mines in Rhodesia aroused interest in London and Paris, and these cities provided the capital necessary for the investigation of the ancient minee in West Africa and Egypt. Speculation resulted in the division of most of the uncultivated area of Egypt and the Sudan into huge concessions, and a number of expeditions were made; but after an unprecedented activity in West Africa, roaction set in, and the flow of capital ceased. The concession- aires, mostly individuals with insufficient capital and with a misconception of the initial difficulties of communication, water supply, and labor, allowed

Jan 1, 1932

By E. K. Stanek

This report contains the results of an investigation into the feasibility of periodically measuring parameters of the insulation for a mine electrical power system in order to detect incipient faults. The variety of insulation parameters evaluated included insulation resistance, dissipation factor, power factor (vs. applied voltage), current harmonics, leakage current, infrared radiation, as well as certain circuit breaker parameters and tests. In order to augment field tests a program of accelerated life testing was also carried out. Apparent inconsistencies in data were identified as the result of environmental effects, primarily temperature and relative humidity. A series of environmental tests were conducted to develop correction factors that allow one to refer measured parameters to standard conditions. A portable data collector was develop-ed to aid in the accurate collection and analysis of laboratory and field data. The primary conclusion is that insulation deterioration can be measured and failure predicted with reasonable confidence. The secondary conclusion is that most of the tests are impractical in the field although useful in the laboratory. Infrared sensing, insulation resistance and dissipation factor are the best insulation field tests when portability is taken into account.

Jan 1, 1979

By Ernest W. Loya

The Bureau of Mines has developed a computer program for calculating the composition of gravimetric primary standard gas mixtures. The Fortran IV program applies corrections due to buoyancy variations of the cylinder and inaccuracies of the balance weights. The program also determines the statistical error due to the sensitivity and precision of the balance and applies the analytical error of the weighed gases.

Jan 1, 1985

By R. V. Lundquist, A. E. Morris, E. L. Singleton

This experimental research was performed to determine rate - of - reaction constants on the MnO - C and Mn , C₂ - 3MnO systems at 1,100 ° , 1,150 ° , and 1,185 ° C. Reactions were conducted at atmospheric pressure under controlled flow of purified helium through the furnace chamber . The weight - loss method defined reduction percentages , and reaction products were identified by X- ray methods . The system Mn0 - C followed a linear reaction rate , and experimental results produced an apparent activation energy of 55.8 kcal per mole of Mn0 . The system Mn, C - 3Mn0 followed a parabolic rate of reaction law and yielded an apparent activation energy of 114.4 kcal per mole for the reaction .

Jan 1, 1964

By D. E. Wolfson

As a part of its overall program of coal carbonization, the Bureau of Mines is studying the coking properties of coals that may be used for metallurgical purposes. The objectives of this study were given in detail in a previous report.2/ The inherent suitability of coal for metallurgical use depends primarily on (1) chemical composition, (2) preparation characteristics, and (3) carbonization behavior. The first two factors, as well as the available reserves, are considered in selecting coals for carbonization tests.

Jan 1, 1957

By E. C. Lane

The motor gasoline that is being marketed in the United States this winter is in general, more volatile than that sold a year ago. This increase in volatility is shown by a lowering of the distillation temperatures, ranging from 2°F. at the average initial boiling point to 5°F. at the average end point. During the past eight and. one half years the Bureau of Mines has made semi-annual surveys of the gasoline marketed in the United States, the survey Just completed being the seventeenth in the series. The cities in which samples have been collected, have been chosen as representative of the more important marketing territories, as it is obviously impracticable to obtain a sample of every gasoline sold in the entire country. Samples were collected in Boston for the first time since 1919. It was believed advisable to include samples from that district in order to give a better balance to the survey for the country as a whole.

Jan 1, 1928