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By Charles D. Litton

This U.S. Bureau of Mines report describes the results of two large-scale tests conducted to evaluate a prototype nitric oxide (NO)-compensated carbon monoxide (CO) fire sensor, developed by Carnegie Mellon Research Institute (CMRI). In the tests, small coal fires were allowed to develop in the presence of diesel exhaust at relatively low ventilation airflows. These tests compared the response of the CMRI fire sensor with that of other fire sensors, including the Bureau's diesel-discriminating smoke detector. During the tests, CO, NO, and smoke levels were continuously monitored in order to determine the sensor alarm times and gas levels as the fire developed. The data indicated that the NO-compensated CO fire sensor was capable of suppressing the CO produced by a diesel engine and that the sensor responded reliably to the CO produced from the test fires. The tests also showed that the Bureau's diesel-discriminating smoke detector alarmed earlier than the prototype NO-compensated CO fire sensor.

Jan 1, 1993

By D. E. Andrus

This paper, which describes the milling practice at the Montana mine concentrator of the Eagle-Picher Lead Co., is one of a series being prepared by the United Slates Bureau of Mines. LOCATION The Montana mine is situated on the eastern edge of the Oro Blanco mountains at an elevation of 4,300 feet. It is in the Oro Blanco mining district, Santa Cruz County, in the southern part of Arizona, about 4 miles north of the Mexican border, 30 miles northwest of Nogales and 80 miles southwest of Tucson. Amado, a station on the Southern Pacific Railroad, midway between Tucson and Nogales, and about 40 miles northeast of the mine, is the shipping point and is reached over an excellent highway.

Jan 1, 1931

By H. D. Hess

This report describes in detail a unique occurrence of fersmite, (Ca, Ce, Na) (Cb, Ti, Fe, Al)2 (0, OH, F)6, which occurs as small anhedral inclusions and intergrowths with a tantalum-free columbite found in the metamorphic complexes of Ravalli County, Mont. Chemical and crystallographic data along with the physical and optical properties agree in general with those given in the original description of fersmite from the Ural Mountains of Russia. X-ray diffraction data not given in the original description and more specific optical data have been determined. The Montana fersmite, now established as the second occurrence of this rare calcium-columbate mineral, was discovered during a routine Bureau of Mines mineralogical examination of a prospector's sample.

Jan 1, 1960

By O. C. Blade

A comparison of certain properties of the commercial aviation gasolines produced in the United States during October 1949, 1950, and 1951 is presented in table 1, the 1951 data being average values from tables 3 through 6 of the present report. Trends in the average values of certain characteristics of these fuels may be seen in figures 1 through 4 which also indicate the minimum and maximum values. As may be observed, with the exception of changes in kinematic viscosities, the properties of commercial aviation gasolines have not varied greatly during recent years. A list of aviation-gasoline survey reports published by the Bureau of Mines is given on page 6. A summary of the average values of the properties on jet fuels is shown in table 2.

Jan 1, 1952

By M. J. Kovalik, D. E. Wolfson, F. Fischler

Plastometric tests were made to determine the maximum thickness of the plastic layer for different U.S. coals . The effect of test variables on the maximum thickness of the plastic layer was studied . The values for the maximum thickness of the plastic layer were found to be related to the Gieseler maximum fluidity , plastic temperature range , free swelling index , and other plastic properties of coals . Only a general relationship was observed between the plastometric parameters obtained in these tests and the coking properties of coal .

Jan 1, 1964

By Kenneth Maas

The Bureau of Mines devoted portions of the 1987-1988 field seasons to investigate the mineral aggregate industry in Juneau, Skagway, Haines, and Gustavus, Alaska, as part of the Juneau Mining District study. Statistics compiled for current suppliers include location, activity, reserve estimates, expected mine life, and types of commodities available. Each population center, except for Gustavus, is well endowed with suitable mineral aggregate to last at least 20 years. The Bureau of Mines quantified the mineral aggregate resource in many large potential sites within each area. Sampling, engineering and soil-index testing, site descriptions, deposit dimensions, and gold recovery information is described. Refraction seismic studies performed at three localities revealed gravel thicknesses in excess of 40 to 80 feet. In the Juneau area the Herbert/Eagle Rivers outwash area, East Fork Lace River. Antler/Gilkey Rivers, and Grizzly Bar (Taku Inlet) individually contain in excess of 60 million yd3 of excellent-quality aggregate with minor accessory gold credits. Haines is also well endowed with aggregate resources; large, quality deposits occur along and at the confluences of the Chilkat, Katzehin, Klehini, Tsirku, and Kicking Horse Rivers. Large deposits of granitic aggregate exist in the Skagway River and East Fork Skagway River.

Jan 1, 2012

By Robert L. Virta

The Bureau of Mines examined a fibrous talc sample from the Gouverneur talc district in New York by transmission electron microscopy (TEM) and polarized light microscopy to determine the mineralogical relationship of the fibrous talc to the amphiboles present in the sample. Two am-phiboles, anthophyllite and tremolite, were present in the sample. Tremolite occurred as a separate mineral phase, which was blocky in habit. Only a few composite tremolite-talc grains were observed. An-thophyllite, however, was present only in the fibrous talc grains. Mi-crodiffraction study of the fibrous talc grains containing anthophyllite showed that the anthophyllite was intermixed with the talc on a fine scale and that there was a crystallographic relationship between the talc and anthophyllite lattices in the fibrous talc grains. A mechanism similar to the process that forms biopyriboles could explain the structural defects, the fibrous habit of the talc, and the structural relationship between the talc and anthophyllite in the fibrous talc grains. Because of these characteristics, phase contrast microscopy and a provisional TEM technique for monitoring asbestos exposure would not distinguish between fibrous talc and fibrous amphiboles. TEM techniques employing electron diffraction and energy-dispersive X-ray analysis are recommended to positively identify the fibrous phases for regulatory purposes.

Jan 1, 1985

By R. J. Bielicki

A sorption apparatus for measuring the equilibrium sorption isotherm and the rate of diffusion of methane from fine-sized coal was designed and constructed. Preliminary work that used Pittsburgh and Pocahontas No. 3 coal shows that the diffusion coefficient varies with pressure and that the fracture spacing in these two coals is substantially different.

Jan 1, 1972

By A. L. Engel

This report describes results of laboratory-scale experimental treatment of nine ores containing gold and silver, including samples of products of previous plant treatment, from ore deposits in California and Nevada. The samples treated were taken by engineers of the Bureau of Mines during investigations of these ore deposits. The information reported is of interest for development of the mining districts represented or in future Investigations of similar ores from other sources. The treatment methods were as simple as possible. More complicated treatments were tried when required, The applicability of the methods and their limitations in treating the ores are shown by the data in this report. The following treatment methods were employed in the experiments described: Screen analyses were made to determine distribution of values in various screened-sized portions of crushed ore, or to determine optimum size to which a particular ore should be crushed or ground to liberate values, and some-times to determine residual values in various-sized portions of treated material.

Jan 1, 1961

By Ellis S. Hertzog

The material published in this report is part of a special study of some of the chemical and physical properties of Alabama coals. The complete study included friability and grindability determinations, high and low temperature assay distillation tests, and ash fusion-temperature determinations. Proximate and ultimate analyses and. calorific values of the coal samples also were obtained. This paper is concerned only with grindabilities, although proximate analyses have been included to give a better picture of the problem as a whole. The growing interest in grindabilities of coals is a result of the increase in use of pulverized fuel in REscent years. The tenative ball-mill grindability method D409-35T4/was used in making all the determinations. The method of sampling and the technic of the testing procedure is described in Considerable detail in this report because the procedure was established quite recently. The ball-Mill grindability index is a measure of the ease with which coal may be ground, which may be an important factor in estimating pulverizing costs. Up to the present time few data on the grindability of Alabama coals have been published. The data in this paper show that the Warrior and Cahaba fields exhibit a wide range of grindability in their coals. The mines tested are well distributed throughout the productive areas of these fields, and it is possible to make rough estimates of the grindabilities of coals not listed in this report from the data given for mines situated in the same vicinity. ACKNOWLEDGMENTS This study was conducted at the Southern Experiment Station of the Bureau of Mines in cooperation with the University of Alabama. The Alabama liming Institute was of great assistance in furthering the investigation, and the work was undertaken largely as a result of its request that the Bureau of Mines should make certain studies of Alabama coals. Grateful acknowledgments

Jan 1, 1938

By Welby G. Courtney

The Bureau of Mines conducted a field test program in the Pittsburgh coal seam to investigate the effect of water sprays in the suppression of respirable dust being formed while cutting with a continuous-mining machine. Emphasis was given to the location of spray nozzles on the top and bottom of the cutting boom. Results showed that (1) sumping caused about 60 percent of the dust escaping the face area, and shearing and loading caused the other 40 percent; (2) during sumping, top and bottom sprays were equally effective in dust suppression and reduced dust ~13 percent; (3) during shearing and loading, bottom sprays reduced dust 61 percent and were about 50 percent more effective than top sprays; (4) the combination of top and bottom sprays was slightly more effective than the separate systems, but water consumption increased 60 percent; and (5) inclusion of throat sprays decreased dust reduction by removing some of the water from top and bottom sprays where it was more effective.

Jan 1, 1978

By William Rachunis

This publication describes the construction of 43.64 miles of underground tunnel to be used as an aqueduct, known as the West Delaware aqueduct. In the past, the accident history of tunnel operations has not been favorable, the "rule of thumb" being a death for each mile of progress, according to the meager accident statistics available for the tunnel-driving industry. The accident experience at this project and the use of modern equipment established safety and progress records that were accepted by tunnel people as a record at the time. The city of New York comprises 5 boroughs, with a total population of approximately 8 million people, and uses about 1,210 million gallons of water each day. The water supply for the city is the responsibility of the New York City Board of Water Supply. This organization has constructed an extensive aqueduct system, the Delaware aqueduct, to convey water to the city from the distant mountain and river sources in the Catskill Mountains in the Southern Tier areas of New York State (figs. 1 and 2).

Jan 1, 1962

By Robert E. Meredith, Thomas T. Campbell

An investigation was undertaken to examine the feasibility of employing low- temperature nonaqueous baths for electrodepositing some of the refractory metals of the ferroalloy group . To date , such metals as tungsten , molybdenum , and vanadium have been produced only by high - temperature processes that are technically difficult and sometimes cumbersome in operation . Deposition studies were performed in a wide variety of organic solvents , including amides , ammonia derivatives , ketones , polyhydroxy alcohols , and ethers . Compounds prepared and used as solutes included the chloride and bromide salts of vanadium , tungsten , and molybdenum . Studies were conducted over a temperature range of 20 ° to 200 ° C under inert atmosphere . Conductivity and current potential data were obtained for all baths that contained reasonable solute concentrations . Qualitative solubility data were obtained for compounds of ferroalloy metals in a variety of solvents . In general , all solutes showed low solubility in ethers and ketones but reasonable solubility ( in excess of 20 grams per liter ) in alcohols , amides , and ammonia derivatives . No successful metallic deposits that would encourage further study were obtained with any of the systems that were examined .

Jan 1, 1963

By Thomas W. Thompson

The Zebulon manganese deposit has been known for a number of years. It is situated about 3 miles east of Zebulon, Wake County, N. C., on the Avon, Privett property (fig. 1). The deposit outcrops as a vein, or dike averaging-16 to 20 feet in width. Drilling by the Bureau of Mines has shown that this outcrop results from consolidation of a number of small stringers near the surface. The surface width and the Percentage of manganese oxides (resulting from. weathering) diminish with depth. Below 50 to 80 feet, the vein material is mainly quartz and spessartite garnet. The deposit was first examined by W. T. Benson, a Bureau of Mines engineer, in 1941. The Bureau conducted a diamond-drilling exploratory program an the property from November 7, 1944, to January 25, 1945. A. total of 2,508.5 feet was drilled in 14 holes along the strike of the deposit.

Jan 1, 1950

By H .. B. HUMPHREY, F. E. Cash

Sixty-one fatal accidents were reported in the mines of Alabama during 1930. This number is a decrease of 15 per cent as compared with 1929; however, production was 13 per cent and the man-hours worked were 16 per cent less than in the previous year. There were 21,731 men employed inside and 3,386 outside. Table 1 gives the comparative rates per million tons and per million man-hours for the United States and for Alabama for 1929 and 1930. These rates are based on figures published by the State and by the United States Bureau of Mines, with preliminary figures for 1930. (These sources of data are used throughout this paper.)

Oct 1, 1931

By J. W. Eckerd

The crushing of chestnut-size (1-5/8 by 13/16 inch) Pennsylvania anthracite in four commercial crushers (impact) jaw) hammer-mill) and gyratory types) was studied by the Bureau of Mines to determine which could produce the largest proportions of buckwheat Nos. 1 and 2 sizes (9/16 by 3/16 inch). Single pass dry and wet crushing techniques and the effect of stage crushing were evaluated. Calculations were made to show the effect of closed-circuit reduction on production rates and yield of the various sizes. The data show that the gyratory crushers produced the greatest percentage of the desired sizes. A ring-type hammer mill produced the greatest tonnage of buckwheat No.1 and rice (14.9 tons per hr.) during dry grinding tests) but the yield of these sizes was only about 55 percent) as compared with 62 to 70 percent for the gyratory crushers. The impact and jaw crushers produced the smallest amount of buckwheat and rice and the largest quantity of oversize material.

Jan 1, 1960

By S. G. McAnally

This is one of a series of papers describing mining and crushing methods and costs at cement plant quarries throughout the United States and deals directly with the methods employed and costs obtained at the Reliance quarry of the Giant Portland Cement Co. at Egypt, Pa., although it is more or less descriptive of the methods used throughout the Lehigh Valley cement district. Systems of transportation vary according to local conditions, such as proximity to the mill, depth of quarry floor with relation to the mill level, etc. Methods of prospecting differ mainly in the type f drills used. Systems of storage, crushing, and grinding vary chiefly in the types of units. ACKNOWLEDGMENTS Most of the information regarding the early history of the Lehigh cement district was obtained from the History f the Portland Cement Industry of the United States, by Robert W. Lesley, the first president of the Portland Cement Association. The writer is indebted also to Charles Clader, Giant Portland Cement Co. quarry superintendent, for valuable information regarding present and past methods and equipment.

Jan 1, 1931

By Donald W. Mitchell, John Nagy, Edwin M. Murphy

To increase safety and productivity in mining , the potential uses and hazards of rigid foam were investigated by the Bureau of Mines Experimental Coal Mine . This research resulted in the development of chemical formulations , spraying equipment , and application procedures that permit safe and effective use of urethane foams for improving mine ventilation , for reducing weathering of mine rock and steel , for constructing seals in fire areas , and for thermal insulation .

Jan 1, 1964

By Jack D. Ramsdell

Electrorefined, magnesium-reduced, and sodium-reduced titanium samples were evaluated for recrystallization behavior, effect of cold rolling on tensile properties, and bend ductility. Curves were determined for the softening of 2.5 to 80 percent reduced cold-rolled metal that was annealed over a temperature range of 300° to 800° C. Upon annealing, coarsening of the grains was found to occur for reductions in thickness of less than 20 percent in titanium made by all three processes. The presence of metallic impurities greatly inhibits coarsening for reductions in thickness below 20 percent, but for reductions in excess of 20 percent grain size is essentially constant at each annealing temperature. The three grades of titanium did not harden excessively from cold rolling; both tensile and bend ductility were good for reduction in thickness up to 80 percent. Upon annealing, softening occurs between 400° and 600° C., and, based on microstructure and property studies, full annealing is accomplished after 30 minutes at 700° C. for the magnesium-reduced and electrorefined titanium and at 800° C. for the sodium-reduced titanium.

Jan 1, 1960

By T. A. Henrie, E. K. Kleespies

Carbon reduction of rutile and ilmenite in nitrogen and ammonia atmospheres was studied as a method of preparing titanium nitride . Ammonia was a better nitriding agent than nitrogen . The contact between the solid reactants , carbon and rutile , was a prime factor in nitrogen atmospheres and was of lesser import in dissociated ammonia . The reduction process for conversion of rutile to the nitride required carbon . The nitriding of ilmenite- carbon mixtures produced titanium nitride and elemental iron .

Jan 1, 1964