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By Maria I. De Rosa

The U.S. Bureau of Mines performed experiments to determine if primary gas toxicities that evolve during the early (~300° C) and later (~.400° C) combustion stages of polyvinyl chloride and chlorinated brattices could be predicted by a smoke particle characteristic, which could be used as a simple and inexpensive test parameter. The experiments were conducted in an approximately 20-L furnace at set furnace temperatures of 2500 and 1,0000 C, for 14 min duration, with an airflow through the furnace of 10 L/min. The variables studied, as a function of time, were the hydrogen chloride (HCl) and carbon monoxide (CO) concentrations, sample and furnace temperatures, the sample mass weight loss, the average smoke particle diameter (dg and number 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 (l/dgno) correlates directly with the primary gas toxicities evolved during both stages of combustion.

Jan 1, 1989

By Walter Pajalich

This Bureau of Mines report is a study of the organizational framework of the ferrous scrap industry, of the products produced, and of the factors affecting the consumption of ferrous scrap by the steel industry. Consumption data from 27 major iron and steel firms in the States of Illinois, Indiana, Iowa, Michigan, Minnesota, and Wisconsin during the period between 1957 to 1962 were grouped by type of iron and steel furnace production facilities to determine consumption pattern for various grades of scrap in comparison to ingot production, hot metal consumption, and home scrap generation. Grades of scrap affected by changes in scrap consumption were determined, and the pattern that emerged was analyzed. Correlation of scrap demand and its effects on scrap prices based on price of scrap receipts of No. 1 heavy melting scrap and No. 2 bundles in the Chicago area for the years 1957 through 1962 indicated that demand trends do not always affect the price of scrap, Past and present technological advancements in steelmaking processes are discussed, and their effects on the scrap industry are analyzed.

Jan 1, 1967

By K. K. Kelley

"INTRODUCTION The Bureau of Mines nitrogen peroxide process (2) 3/ for extracting manganese from low-grade ores is essentially a two-stage process involving the reversible reactionMnO2 + 2NO2 + 6H2O = Mn (NO3)2 . 6H2O (1).At lower temperatures this reaction proceeds to the rigth and affords a means of dissolving manganece and separating it from unreacted ore. At higher temperatures the reaction proceeds to the left and manganese dioxide is recovered and nitrogen peroxide regenerated for recycling. Evidently, therefore, the energy required for decomposition of manganous nitrate is a matter of practical importance. Similar information for certain other nitrates also is desirable beceuse the nitration step of the process produces appreciable amounts of nitrates of other metals, such as iron, aluminum, magnesium, calcium, and barium, some of which are not broken down in the evaporation and decomposition steps. Thus, a portion of the nitrogen peroxide is not directly available for recycling. Whether or not it is feasible to recover nitrogen peroxide locked in the more-stable nitrates depends partly on the energy required and the conditions necessary for their decomposition.To supply information bearing directly on these subjects, several researches were undertaken at the Pacific Experiment Station: (a) Heats of formation (24, 25, 26) of nitrates of manganese, magnesium, calcium, barium, and aluminum were measured at 298.2° K:; (b) low-temperature specific heats (23), in the range 51° to 298.2° K,, and entropies of nitrates of magnesium, calcium, barium, and aluminumm were determined; and (c) heat contents (21) above 298.2° K. of the nitrates of manganese, magnesium, calcium., and barium were measured. The results of these studies, when correlated by thermodymamic methods, permit evaluation, at any temperature of interest, of the energies required to decomposethe nitrates and furnish information concerning the equilibrium pressure temperature relationships."

Sep 1, 1944

By Leonard Obert

THIS REPORT presents methods and principles useful in designing underground mine openings and pillars in competent rock formations. Two types of formations are considered: (1) Massive formations, in which openings are generally mined with an arched roof, and (2) bedded formations, in which openings are generally mined with a flat roof. Design principles for openings and pillars in massive formations are obtained by considering the maximum tangential stresses developed around single and multiple openings for stress fields of various types. Design principles for openings and pillars in bedded formations are obtained by considering the average stress in pillars and the maximum stresses in roof layers. Experimental procedures for making stress, strain, and in situ physical-property measurements in underground mines to check design calculations are outlined and the results discussed.

Jan 1, 1960

By D. Harrington

Fire is always a serious-menace, whether in a residential or in an industrial region; in wartime it is particularly damaging in an industrial plant. The mining industry is especially vulnerable, as its plants are generally more or less isolated front centers of population and do not have access to modern fire-fighting equipment; moreover, owing to the transitory rapture of most mines, their surface structures; are often relatively flimsy and flammable.. Trained firemen seldom are available at or near mining plants to teach the fundamentals of fire-fighting to local fire brigades, with the result that efficiency in combating actual fires is lacking. Often the attitude "it can't happen here" is held by the management of a mining property, unless the plant has suffered a serious fire; even then lapse of time is very likely to induce forgetfulness as to the possible hazards. The necessity for producing metals for the prosecution of this war has increased management's responsibility. Whereas heretofore the loss of a plant or mill by fire meant merely monetary less to the stockholder of the company, now the national interest is affected, in that the nation suffers from loss of production of minerals indispensable for war purposes.

Jan 1, 1943

By Ralph Husack

The Bureau of Mines investigated the effect of gamma radiation on reactions between Pennsylvania anthracite and fluorine and chlorine. In the tests with fluorine about 90 percent of the coal reacted at 350° C to form volatile products whether or not irradiation was employed. Up to 0.8 ml of liquid products per gram of anthracite was collected. Among the 25 com-pounds indicated by gas chromatography, fluoroform and l,l-difluoroethylene were tentatively identified from their relative retention times and perfluoro-cyclopentane from its infrared spectrum. In addition, a clear, hard, wax, probably a fluorocarbon, was formed at 45° C in both the presence and absence of radiation. With chlorine there was no significant difference due to radiation, and preliminary tests indicated that the chlorine reacted more with the organic matter of anthracite at 200° C than with inorganic matter. At 400° C the results were inconclusive because of excessive corrosion in the reaction vessel.

Jan 1, 1966

By Richard D. Miller

This publication contains routine analyses and related source data for 434 gas samples from 16 States. These samples were collected during calendar year 1961 as part of the continuous survey for the occurrence of helium in natural gas conducted by the Helium Activity of the Bureau of Mines. The analyses herein were made by mass spectrometer and Frost helium apparatus. The most important helium resource discovery made during 1961 was the Table Mesa field in San Juan County, N. Mex. This field, Which has an estimated recoverable helium reserve of 850 million cubic feet, is now supplying gas containing approximately 5.4 percent helium to the Bureau of Mines Navajo Helium Plant at Shiprock, N. Mex.

Jan 1, 1964

By Richard D. Miller

This publication contains routine analyses and related source data for 434 gas samples from 16 States. These samples were collected during calendar year 1961 as part of the continuous survey for the occurrence of helium in natural gas conducted by the Helium Activity of the Bureau of Mines. The analyses herein were made by mass spectrometer and Frost helium apparatus. The most important helium resource discovery made during 1961 was the Table Mesa field in San Juan County, N. Mex. This field, Which has an estimated recoverable helium reserve of 850 million cubic feet, is now supplying gas containing approximately 5.4 percent helium to the Bureau of Mines Navajo Helium Plant at Shiprock, N. Mex.

Jan 1, 1964

By Robert W. McKibbin

The Bureau of Mines conducted laboratory tests to determine the slurry transport and deposition properties of coal waste. A 188.5-ft pipe test loop was constructed with instruments to measure density, flow, and power and discharge, suction, and differential pressures. A 20-ton ample of Western coal waste was crushed and screened to 100 pct minus 1/2 in. Eight loop tests using this graded waste were run at slurry densities ranging from 1.15 (25 wt-pct solids) to 1.46 (60 wt-pct sol-ids) 0 The resultant friction-'pressure gradients ranged from 0,06 to 0.24 ft of water per foot of 4-in standard steel pipe. Particle-size degradation was significant.. In a typical loop test lasting 25 min, the minus 200-mesh fraction increased from 19 pct to 34 pct. Deposition tests showed that without the use of a flocculant, the slurries would not dewater when left to stand for 1 week. With flocculant, additional water was releas2d; however, the settled slurries remained thixotropic. Further testing is necessary to determine their suitability for use as backfill material in active mines.

Jan 1, 1983

By J. W. Paul

This circular is one of a series of reports on coal mining methods and cost s which are being prepared by the U. S. Bureau of Mines for the purpose of making available to those interested in the industry a knowledge of the mining methods employed in mines where mechanical and hand loading is practiced and the cost data on the several operations pertaining to the removal of coal from the working faces and its transportation to the tipple for loading into railroad cars. The methods employed are influenced by the natural local conditions with respect to the thickness and character of the coal beds and the overlying strata, the means employed for roof support and its control, and the disadvantages incident to the development of mines in thin coal beds.

Jan 1, 1929

Watershed Jll in Jefferson County, Ohio we instrumented in 1977 as one of three watersheds established for the purpose of investigating surface mining and reclamation effects upon local hydrology, sediment discharge, and sediment and water quality. Each watershed was less than 50-acres in size, and was in a different geologic setting within southeastern Ohio. Surface runoff and ground¬water levels were monitored. Samples were taken for sediment determination and chemical analysis prior to mining. Monitoring and sampling continued through the period of watershed disturbance caused by mining and reclamation activities, which began in May 1980 at Watershed Jll. A psuedo-postreclamation period followed the initial cessation of man-machine activity on the watershed. A second reclamation effort occurred in the fall of 1981 and was to be followed by a third in 1982 after observations ceased. A true final postreclamation period was not monitored at this site, because the erosion control practice (terrace diversions) failed after each reclamation. Watershed Jll was a small pasture and wooded watershed with sandstone and shale above the mined coal seam prior to mining. A clay layer under the coal supported a perched saturated zone, termed the top aquifer for convenience. A lower underclay supported a second saturated zone called the middle aquifer. A lower perched aquifer had been dewatered by previous deep mining. After about three years of premine data and about two and one-half years of mining reclamation and psuedo-postreclamation data, the following general observations may be made: 1. The mining-reclamation phase was very short, and the postmining period was characterized by erosion failures and remedial disturbances that kept the watershed condition and size in a state of change. It was impossible to collect sufficient data to confidently characterize the hydrologic-sediment-chemical aspects of the mining period or of a postreclamation period and, most importantly, of the future watershed after its various properties and characteristics have ceased adjusting to its severe disturbance and reconstitution. 2. A seeding of wheat followed by grasses and legumes was not a particularly successful reclamation practice in terms of stabilizing the new soil. Numerous rills and small gullies developed in spite of installed diversions. 3. Storm runoff rates and yields at the watershed outlet increased from the premine, (phase 1) to the mining-reclamation (Phase 2) periods, and remained at or near the Phase 2 level through the postreclamation (Phase 3a) period. 4. The top aquifer changed in physical and chemical character as a result of mining and was becoming reestablished as the project drew to a close; but it is impossible to predict its final configuration or character. 5. Dewatering of the top aquifer resulted in a complete cessation of baseflow because the middle aquifer water table lay below the elevation of the watershed outlet. 6. The top and middle aquifers were merged in one area of the watershed where the upper coal underclay was disturbed. 7. Failure of the diversion terraces and their outlet obscured the effects of the reclamation practice upon sediment concentration and yields. There was little difference in sediment concentrations between Phases 2 and 3a. 8. Drinking water standards were met by surface waters throughout the period of observation except for two samples that exceeded the nitrate-N allowable level of 10 mg/l. 9. In all Phase 3 surface-water samples, iron concentrations were within the limits established by OSM, and manganese concentrations exceeded the regulation level only once. pH fell below the lower regulation level of 6.0 between 10% and 20% of the time. 10. The chemical quality of sediments was generally about the same after reclamation as before mining, with the exception of organic carbon, which decreased.

Jan 1, 1983

By A. T. Iannacchione

The Bureau of Mines established geologic factors affecting the mining of the Lower Kittanning coalbed to aid in coalbed minability studies and examined the occurrence of "wants" (places where coal is missing) and types of unstable roof rock strata. Trends established from mapping, including prediction of areas of high methane emissions, were extrapolated to unmined areas. 'Wants' in the coalbed are of two types: Erosional and depositional. Erosional features occur where north-south-trending sand-filled channels cut into the coalbed. Variations in depositional environments have caused the coalbed to "split" into several thinner units. Slickensides, commonly indicative of unstable roof, are adjacent to and on the underside of sandstone channels; they were caused by differential compaction and by soft sediment sliding along the contact between the sandstone and adjacent shale. The frequency of unstable roof also increases where the interval between the Middle and Lower Kittanning coalbed is less than 30 feet. The zones of weakness at the contacts above and below the Middle Kittanning coalbed are the controlling factors for unstable roof in these strata. Methane emissions from the coalbed are controlled primarily by depth, fracture permeability, and rank of coal. Local geologic factors are coalbed thickness, associated rock strata, structure, and proximity to outcrop.

Jan 1, 1979

By Oliver C. Ralston

Nonmetallic technologic investigations of the U. S. Bureau of Mines are headquartered at experiment stations in three widely separated localities of the United States. During 1936, the Nonmetals Division of the Technologic Branch was formally set up by combining the direction off the work of these three experiment stations under one administration. The New Brunswick (N.J.) station which in the past has been known as the Nonmetallic Minerals Experiment Station, is henceforth to be at College Park, Md., as part of the Eastern Experiment Station, and its principal activities will be related to the nonmetallic resources of the Eastern and New England States.

Jan 1, 1937

By P. A. Lawless

The objective of the research performed A for the Bureau of Mines on this contract was to develop a portable instrument for the detection of carbon monoxide (CO) in a mine environment. The desired characteristics were sensitivity and specificity for CO with a stable calibration. The sensor of the instrument was to be of metal oxide composition, requiring low power for compatibility with the types of batteries presently used in personal equipment in mines. The solid state design was also desired for ruggedness and small size. A key design feature of the instrument was to be provided by adherence to the intrinsic safety design requirements for electrical equipments operated in potentially exposive mine atmosphere. The Research Triangle Institute has prior experience in developing a solid state oxygen sensor using a thin film of zinc-oxide (Ref. 1) and experience in fabricating thin film devices. Solid state sensors utilized by other workers (Refs. 2, 3, 4, 5, 6) have included metal and semiconductor films and crystals of materials like carbon and aluminum oxide for the measurement of water vapor in the air and have relied upon measuring resistance and capacitance changes in the sensor in response to adsorbed vapors or gases. Since the effect of carbon monoxide in changing the resistance of various materials such as molybdenum, platinum, and zinc oxide had been reported (Refs. 7, 8, 9, 10), the requirements appeared to be realisable, although it was recognized even at the inception of the work that specificity to carbon monoxide might require the incorporation of more than one sensor.

Jan 1, 1976

By Robert L. Lappi

Eight interburden handling concepts are developed for multiple seam area mine stripping operations in central and western United States. They are based on data gathered and analyzed during field surveys, literature reviews and visits to state regulatory agencies in five states. It is concluded that improvement of reclamation practices through selective interburden handling techniques is possible at lower operating costs than currently incurred. Specific multiple seam mining systems are discussed in this report.

Jan 1, 1980

By Terry J. Close

At the request of the Idaho Congressional Delegation, the U.S. Bureau of Mines Western Field Operations Center investigated the mineral resources of the 140,000-acre Red Mountain roadless area, located northeast of Lowman, in central Idaho. The area includes U.S. Forest Service Red Mountain RARE II area (4-063). The highly mineralized road less area is underlain mainly by granitic rocks which are transected by a northeast-trending fault system. Associated with the granitic rocks and fault system are gold and black sand mineral resources. At least 1,395 ounces of gold and 858 ounces of silver have been recovered from six lode and placer mines within the roadless area. A total of 525 tons of columbium-tantalum, 2,049 tons of euxenite, 83.5 tons of columbite, and 54,862 tons of ilmenite concentrates have been produced from a nearby black sand mineral placer. Mine workings and facilities in the roadless area consist of two dismantled mills, 15 open and caved underground excavations totaling about 2,900 ft of workings, seven large pits and quarries, over 166 smaller dozer-and hand-dug prospect pits and trenches, and in excess of 66 drill holes. The mineralized sites in the roadless area are covered by about 690 current (1992) mining claims. About 130 individuals are holding the claims. Also within the roadless area are four patented lode mining claims. Twenty-five of the 54 mineralized sites identified during the study of the roadless area have, or likely have, mineral resources. One has gold and three have black sand mineral resources that are marginal or subeconomic. There also are two hot springs with thermal water resources, some veins that could be sources of decorative quartz, and dimension stone which was quarried in the past and could be again.

Jan 1, 1993

By Edward L. Tullis

Numerous widely distributed pegmatites of the southern Black Hills of South Dakota contain small amounts of beryl, and two minor deposits are known in the northern Black Hills. Few mines have produced more than 50 tons, and the current, rate of production for the area is about 100 tons annually. Total production, since the first records, is 2,358 tons. Most of the deposits contain less than 1 percent beryl, although the beryl zones in several deposits contain 2 percent beryl or more. Estimated reserves of beryl total 11,824 tons, and an additional 234 tons has been measured; there are other unestimated reserves. The pegmatites are in a belt about the margin of the Harney Peak batholith in the southern Black Hills, although they fail into three districts. The most important, from the point of view of production and reserves, is the Keystone district. Many deposits also are found in the vicinity of Custer and Pringle. Small amounts of beryl occur in the dikes near Hill City. A little beryl has been produced from the Tinton district in the northern Black Hills, and an undeveloped dike has been discovered on Whitewood Peak near Deadwood. The beryl-bearing pegmatites are principally coarse-grained intergrowths or massive segregations of feldspar, quartz, and mica. Some of them contain notable amounts of lithium minerals, as well as some tantalite, columbite, and cassiterite.

Jan 1, 1952

By Claude W. Sill

In the usual volumetric determination of uranium, the solution containing uranium is reduced in a Jones reductor, yielding a mixture of trivalent and tetravalent uranium; the trivalent uranium is oxidized to the tetravalent state by bubbling a stream of air through the solution. The resulting solution of. Tetravalent uranium is titrated with a standard oxidant, generally sulfatoceric acid, dichromate, or permanganate; It seemed likely that the, same general procedure could be used in determining semimicro quantities of uranium if the conditions affecting the variables involved were understood more clearly than at present. In the method described below, the use of ferric sulfate to oxidize tetravalent uranium allows the titration to be made at room temperature in an essentially colorless solution with sulfatoceric acid. The latter oxidant its turn permits the use of the very stable indicator, ferroin, with its sharp color.., change and exactly reproducible blanks. Solutions of uranyl sulfate were prepared by diluting a stock solution that had been standardized gravimetrically according to the method of Lundell and Knowles (8).3/ Solutions of sulfatoceric acid were prepared according to the directions of G. F. Smith (12) and were standardized against arsenic trioxide in the presence of osmic acid according to the directions of Gleu. The cerium solutions were stored in 18-liter carboys fitted with siphon arrangements so that the bottles did not need to be opened and protected from light in a dark cupboard. Under these conditions, even the 0.01 N solution changed by less than 1 part per thousand over a period of about 6 months.

Jan 1, 1952

By Louis H. Berkelhamer

"INTRODUCTION The method of differential thermal analysis suggested by Le Chatelier (1)1 in 1887 has recently emerged as an outstanding means of studying the constitution of various substances, particularly clays, soils, and miscellaneous hydrous materials (2). The literature ably discusses the applications and results obtained but has paid too little attention to specific details of construction of the apparatus. Knowledge of the apparatus is of importance to the experienced research man as is extremely useful to the novice v ho ventures into this field of analysis. Further, it is generally acknowledged that the variations in design and conditions of operation are one of the essential causes for differences in characteristic temperatures as reported by various investigators. A step forward in the elimination of such differences is the publication of the details of construction and operation of a simple and inexpensive apparatus that has proved useful at the southern Experiment station of the Bureau of Mines, where it was used in cooperation with the University of Alabama, Tuscaloosa, Ala."

Jul 1, 1944

By K. B. Rojiani

Surface mining activities disturb large tracts of land resulting in the potential for greatly increased downstream sediment loads. The Surface Mining Control and Reclamation Act of 1977 places increased emphasis on the protection of the environment from the adverse effects of surface mining operations. Surface mining activities must be planned to minimize disturbance to the hydrologic balance, erosion and sediment contributions to receiving streams. Sediment ponds must provide a sediment storage volume equal to the accumulated sediment volume from the drainage area as determined by the Universal Soil Loss Equation (USLE) or other empirical methods established by the regulatory authority. It has thus become extremely important for the mining industry to secure more accurate estimates of potential erosion losses and sediment yield. Accurate estimates of sediment yield are required for the planning, design and successful operation of sediment control systems such as detention ponds and other alternative control structures and for evaluating the effectiveness of land management practices. The principal soil loss prediction procedure available for use is the LISLE. The USLE procedure is inadequate for use in predicting soil loss from surface mine regions for a number of reasons. These include: 1. The USLE was developed to estimate average average annual loss from agricultural soils. It cannot predict accurately soil loss for specific storm events. In surface mine regions a major portion of the soil loss occurs during the initial six months to one year of active mining. Accurate estimates of soil loss over short periods are thus required for the design of control structures. 2. The slope length and gradient factors used in the USLE were obtained from data or cropland having slopes ranging

Jan 1, 1983