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By Jerry E. Olson

In 1985 the U.S. Bureau of Mines conducted a mineral survey of 68,458 acres of the Clan Alpine Mountains Wilderness Study Area (NV-030-102) which covers 196,128 acres in Churchill County, NV. Most of the area studied is underlain by Tertiary volcanic rocks. In the northeast corner of the study area, an upthrown block of Triassic sedimentary rocks partially extends into the area. The study area is probably part of a large eroded caldera. No major mines or active claims are within the study area. Field investigations included examination of workings in Starr Canyon, historical and recent mining activity near the mouth of Florence Canyon, other mining claims, and anomalous zones delineated by data from Great Basin GEM Joint Venture studies. No mineral resources were identified, but sample results indicate one significant mineralized zone situated along a northwest trend between the head of Starr Canyon and the head of Cherry Creek may contain precious metal resources. Further investigation of this zone is warranted.

Jan 1, 1987

By E. V. Cilento, K. A. DiGregorio, R. C. Lantz

Pulmonary inflammation is accompanied by increased microvascular permeability and leakage of plasma into alveolar spaces. Serum has been shown to affect superoxide (O2-) production from pulmonary alveolar macrophages (PAM) in vitro, and in some cases serum has been shown to be necessary for stimulation of PAM. An electro-optical method was used to measure O2- production from single PAM by measuring the reduction of nitroblue tetrazolium (NBT) to a diformazan precipitate (NBTH2) from videorecorded images of individual cells. PAM were stimulated by their initial attachment to culture dishes independent of serum. The addition of 2% serum to the culture medium increased NBTH2 production during attachment, whereas concentrations of 5 and 10% serum had no additional effect. In contrast, PAM incubated for 2 hrs could not be stimulated by phorbol myristate acetate (PMA) or zymosan particles to produce O2- unless serum was present during the incubation and/or stimulation; however, NBTH production was similar in all cases of serum addition. Also2, serum alone did not stimulate adherent PAM indicating that serum is necessary but not sufficient for stimulation of attached. PAM. These results suggest that changes in microcirculatory permeability may have a pronounced effect on superoxide production by PAM and that serum may help regulate or condition these cells during inflammation of the lung. (Supported by USBOM Gll35142.)

Jan 1, 1988

Improve the performance of waterjet nozzles used for water-jet-assisted cutting to optimize rock cutting efficiency. Approach The performance of a longwall shearer equipped for water-jet-assisted cutting was evaluated during an earlier study (Tech News No. 277). Waterjet nozzles were used to direct the solid streams of water that impacted the rock near the tip bits. The maximum water pressure that could be delivered to the nozzles was about 6,000 psi. Due to the "break up" of the solid stream of water, some of this pressure was lost before the water reached the rock. The pressure could have been increased by moving the nozzle closer to the bit tip but) moving the nozzle too close increases the possibility of damage to the nozzle. Study Results A test apparatus was built to measure water pressure at the location of water jet impact (see illustration). The target, a tungsten carbide plate with a 0.013 inch diameter orifice, was placed at the location of water jet impact. A pressure transducer, used to monitor impact water pressure, was positioned under the plate. Water pressure at the nozzle was maintained at 6,000 psi. The distance between the nozzle and target was varied from 2 to 5 inches.

Jan 1, 1988

By W. E. Wallace, P. Bolsaltis, M. J. Keane, B. L. Rauaboni

Thermal treatment of respirable size silica dust samples results in marked changes in their hemolytic activity. These changes can be correlated with changes in the characteristics of the particle surface as measured by infrared spectra, zeta potentials, and specific surface area. Silica samples from various sources (Min-U-Sil, fumed silica, and a NIOSH standard sample) were heated or calcined at temperatures ranging from 100-1095C. The hemolytic activity of the crystalline materials decreased after thermal treatment. The behavior of the fumed material was found to be more complex. Material of very large surface area (small particle size) exhibits an initial increase in hemolytic activity upon calcination. This result confirms other experimental observations pointing to a particle size of maximum toxicity. Tre changes in hemolytic activity can be related to infrared spectra and zeta potentials of the materials. The absorption band in the 3200-4000 cm-1 frequency region of the fumed material disappears upon heat treatment while a sharp, characteristic band at 3750 cm-1 increases in intensity. Zeta potential measurements conducted in the pH range of 2.0-10.5 exhibit a unique change in zeta potential v.s. pH profile with heat treatment. These findings indicate that the removal of active surface silanol groups by calcination results in reduced cytotoxicity, as measured by a hemolysis test.

Jan 1, 1988

By R D. Fleming

A single-cylinder research engine was operated on pure hydrocarbons and simple (two-component) mixtures of pure hydrocarbons to study the effect of fuel composition on exhaust emissions from a spark-ignition engine. Used as fuels were three pure hydrocarbons that represented the primary hydrocarbon types present in commercial motor fuels: A paraffin (2,2,4-trimethylpentane), an olefin (2,4,4-trimethylpentene-2), and an aromatic (meta-xylene). The engine was operated at the same equivalence ratio for all of the fuels used in the experiment. Exhaust gas samples were collected and quantitatively analyzed for carbon monoxide, carbon dioxide, hydrogen, nitrogen oxides, aldehydes, and hydrocarbons. Exhaust hydrocarbons were separated and quantitatively measured with a chromatographic system employing a flame-ionization detector. Unknown hydrocarbons and oxygenated materials in the exhaust were identified with a Time-of-Flight mass spectrometer coupled to a chromatographic system. The results of the exhaust gas analyses showed that ethylbenzene, l-methyl-3-ethylbenzene, and l-methyl-3-vinylbenzene were more abundant in the exhausts from either 2,2,4-trimethylpentane--m-xylene or 2,4,4-trimethylpentene-2--m-xylene fuel mixtures than in exhaust produced from m-xylene. Also, the pure 2,4,4-trimethylpentene-2 fuel produced smaller amounts of C2 to C7 olefins in the exhaust than that produced by the pure 2,2,4-trimethylpentane fuel. The exhaust from pure m-xylene fuel contained aromatic hydrocarbons of higher molecular weight than the parent fuel. The amount of total hydrocarbon (moles of exhaust hydrocarbon per mole of fuel used) in the exhaust from the three pure fuels decreased in the following order: 2,2,4-trimethylpentane > 2,4,4-trimethylpentene-2 > m-xylene. The hydrocarbon mole-fractions of unreacted fuel in the exhausts produced from each of the pure fuels were 0.20 for 2,2,4-trimethylpentane, 0.13 for 2,4,4-trimethylpentene-2, and 0.66 for m-xylene.

Jan 1, 1970

Enable prospective in situ leach mine operators to evaluate the economic potential of an ore body by using a user-friendly, computerized in situ copper oxide leach mining cost model. Background As part of its research on in situ leach mining technology, the Bureau of Mines produced a 5-volume contract report that mining companies can use to design an in situ mining operation for copper oxide deposits. Written for the Bureau by the Science Applications International Corporation (SAIC) in 1988, the generic design manual also contains a computerized cost model for evaluating the economic feasibility of in situ leach mining for any specific copper oxide deposit. The cost model is to be used with Volume II of the contract report. But because of certain complexities associated with running it, the Bureau found that the model could be improved by making it more user friendly. Approach The approach taken by Bureau researchers to make the original model more user friendly was to incorporate a HELP function to define input parameters, and to enable the display of output on the monitor. An accompanying handbook, U.S. Bureau of Mines Information Circular (IC) 9284, contains further details on running, the 1990 model.

Jan 1, 1991

By Lloyd A. Morley, Alan M. Christman

Presented below is a review of how the objectives, as outlined in the statement of the problem, were achieved. 1. Methods of evaluating the performance of grounding systems must be described. These methods are the subject of Chapter III. 2. Field trips to operating mines should be undertaken, and a cri¬tique of their grounding systems made upon the basis of obser¬vation and the application of the above techniques. An analysis of field trip data, along with practical recommendations, is in¬cluded in Chapter IV, while a complete review of all field trips is given in Appendix I. 3. Because of their thoroughness, present coal mine regulations should be evaluated, and their applicability to open-pit environ¬ments appraised. This has been done in consultation with governmental agency, manufacturing, operating mine, and consult¬ing engineers. As stated in Chapter IV, insight gained through field observations has served to amplify and extend the base of knowledge from which the recommendations were made. 4. The results of these investigations should lead to suggested Federal standards. Such recommendations comprise Appendix II. In addition, several important factors, which are discussed in Chapter IV, were brought to light as a direct result of the field research. 5. Seasonal variations in the earth resistance of ground mats, as illustrated by Table 12, reinforce the need for periodic

Jan 1, 1976

By Liming Yuan, Charles D. Litton

This paper presents experimental results for conveyor belt flame spread from tests conducted in a small-scale tunnel. The purpose of this study is to investigate the effects of belt type, ventilation velocity, belt surface-to-roof distance and ignition source power on the flame spread properties. The tunnel used was 4.9 m long by 0.46 m square with the ventilation velocity ranging from 0.7 to 3.2 m/s. The ignition source was an impinged methane jet burner with heat output ranging from 7 to 21 kW. The belts tested included non-fire resistant rubber belts, fire-resistant rubber belts, fire-resistant neoprene belt and fire-resistant PVC belt with belt samples measuring 0.23 m wide by 2.5 m long. Experimental results show that with a ventilation velocity of 1.02 m/s all conveyor belts could be ignited, and that with sufficient ignition source power, flames spread the full length of the belt sample. The data showed a coupling effect of the ventilation air velocity and the belt surface-to-roof distance on the flame spread rate. For instance, flames could not spread with a ventilation velocity higher than 1.52 m/s and a surface-to-roof distance of 0.22 m. The use of the measured CO/CO2 ratio as an indicator of combustion stoichiometry is also discussed.

By F. R. McDonald

The compound ?-valerolactone has been identified in an acid fraction isolated from waste water collected from an in situ oil-shale retort. Infrared, nuclear magnetic resonance, and mass spectrometry were used by the Bureau of Mines to confirm the identification of a subfraction collected from a gas chromatograph.

Jan 1, 1974

By J. J. Shields

This is the Seventh of a series of publications that describe methods and practices used in mining bituminous coal mechanically.3/ This report deals with the operation referred to in coal mining as continuous mining, and the interest shown by mining companies in this method is the reason for this study. Only continuous mining as it applies to the room-and-pillar system of mining, or a modification thereon, is discussed in detail in this report. Although not always as continuous as the name implies, it is a system of mining in which a machine is used to cut and load coal in one continuous operation without drilling and blasting the coal. With the mining equipment in most general use today, the usual cycle of operation in mining of coal is: (1) Timber, (2) cut, (3) drill, (4) blast, and (5) load. As the phases of this type cycle cannot be performed simultaneously in the same working place, it is necessary to operate from 3 to 7 working places so that at least 1 place is available for coal loading at all times. Even if the schedule of the phases in a cycle is maintained, coal production ceases during the time required to move the loading equipment from one loading place to the next. In 1920 a continuous-type mining machine4/ was installed in an Illinois coal mine to drive entries. Several other companies used these entry drivers for short periods in the following few years. In 1927 a southern Illinois coal company installed 2 of these machines which, in the next 25 years, were reported to have driven over 200 miles of entries. The machines did not attain widespread usage.

Jan 1, 1954

By Wm. W. Odell

This report comprises a brief outline of the experimental cracking of natural gas in a water-gas generator at Louisville, Kentucky, and a discussion of the results obtained. The work was done under a cooperative agreement by the U. S. Bureau of Mines with the Louisville Gas & Electric Co. The re-forming or partial cracking of natural gas is not a new process, but one which has been employed in the manufacture of city gas for a number of years. However, the apparatus used heretofore was not a water-gas generator containing a bed of ignited fuel, but instead it was a plurality of connected chambers containing spaced and arranged checker bricks, with means for heating the bricks and for admitting the natural gas. The procedure previously followed was quite different from that used during the tests at Louisville; likewise the results obtained were different. It is not uncommon for companies distributing natural gas to provide gas-generating equipment for producing manufactured gas which is used, mixed with natural gas, during periods of peak demand. Because this equipment is idle much of the time, in some instances being in use only for a few days a year, some of the gas companies have considered using it, during off-peak periods, in the manufacture of some gaseous products and for carbon black which might he produced and marketed with profit. There is one plant of this kind at Louisville. Kentucky. Its maintenance in condition ready to be operated is necessary because of the limited supply of natural gas and because of the variation in demand. The engineers of the Louisville Gas & Electric Co. considered in particular the possibility of cracking natural gas in a water-gas generator by injecting the gas into the incandescent fuel bed, thereby producing a gas comprised largely of hydrogen (H2) and carbon black, an appreciable amount of which is entrained in the gas as it leaves the generator, Because power and gas are available at low prices, Louisville was believed to be a satisfactory location for a plant which could use hydrogen. It was evident that this method of treating natural gas might directly benefit the gas company by: 1. Lowering, the cost of manufactured gas.

Jan 1, 1930

By James R. Coldwell

Mining and processing cost analyses were conducted by the U.S. Bureau of Mines on stratiform zinc-lead-silver, coal, and stratiform barite deposit types that are found in the Colville Mining District. Reserves and gross revenues which would allow these deposits to be minable were modeled. A 15% Discounted cash-flow rate-of-return economic threshold was selected as the minimum acceptable return on investment for the three deposit types. The economic modeling indicated combinations of grades and tonnages for stratiform sulfide deposits that could be economically viable for orebodies ranging in size from 25 to 130 million metric tons. The gross revenues for a surface mine range from $200/mt for a 5,000 mtpd operation using the proposed South corridor to $140/mt for a 17,000 mtpd mine using the proposed North corridor. The economic modeling indicated underground coal mining was subeconomic for deposits ranging in size from 42 to 250 million metric tons. The required gross revenues ranged from $300/mt for a 2,200 mtpd mine to $21 D/mt for a 13,000 mtpd mine. The economic modeling indicated supplying projected in-state barite demand was subeconomic for the three seasonal surface mines modeled. The required gross revenues ranged from $600/mt for a 90,000 mtpy mine to $840/mt for a 6,000 mtpy mine.

Jan 1, 1995

By S. J. Hussey

The Bureau of Mines investigated the applicability of carbon-in-pulp pro-cess for recovering silver from low-grade ores. The reasons for the research were (1) to illustrate a practical procedure for the process design of carbon-in-pulp adsorption circuits using leach slurries and simple equipment; and (2) to illustrate how equations of adsorption theory relating rate data and equilibrium adsorption curves can be helpful in process design. Carbon-in-pulp silver adsorption tests were made on Banner, Idaho; mine-run ore samples with silver contents ranging from 2.0 to 8.5 oz/ton and variations in cyanide leach extraction from 48 to 93 pet. The lower recoveries were attributed to the presence of complex silver sulfide minerals. Carbon-in-pulp batch adsorption tests provided rate data for the estimation of a silver equilibrium adsorption curve. Process design procedures in which the rate data were related to an equilibrium adsorption curvey by equations of adsorption theory were used to plan a four-stage pilot plant cascade. The pilot plant was successfully operated for 45 hr of countercurrent flow, producing a carbon product containing a mean silver loading of 571 oz/ton from a pregnant solution of 1.7 oz/ton of silver. Virtually all of the dissolved silver was recovered on the carbon.

Jan 1, 1978

By D. B. Dow

In collecting and dissctinating inforr:.at'ion on ir.:,provec.. practices us0i in the pr eduction cf petroleur:1 and in the r;:;.:.1.nuf __ cture of gasoline, the Bureau of Mines ha.s aidei in creatin5 an interest i-n efficient 11:ethods in all phasas of tr.e oil ani gi:i.s iniustry. In the refinin£ ir...mstry ther.:: is a growing tend.ency for incre.:l.sea. effi. ,:;iency, ana inforr;.Eition rela:tin!s to ic:;p·roved practices should be of value not only to the larger and. core efficient plants, but particularly to srr.a.11 refineries unable to carry out a lar6e experLnental pro!§.rarn. The refi?eries of the United States required 4.3,915,029 barrels cf crude oil J.uring the year 1920*, inclu.::.in1:, 611136,210 barrels of Mexican cru::...e. This yielded. 4,8821546,599 gallons of E>asoline, a.n avara.t;,e ciaily pro;.iuct1on of 13,340,291 e,allons·, Besides the easoline obtainel fro;., cruie· oil by-fr:;.cticna.1 distillation and. from heavy oils by crackini:,, this a,-r;ount incluC1.es 3,152,924 bar­rels of natural-ga.$· gasoline blended. With asoline fro,., th otha two sourcs.

Apr 1, 1922

To separate complex mineral mixtures according to their dielectric properties. Approach Develop a laboratory-scale continuous dielectric separator to separate mineral mixtures by exploiting their difference in dielectric properties. How it Works Dielectric separation is de-fined as the separation of particles based on their dielectric properties. The uniqueness of the Bureau's continuous separator, called the ?Rotating Drum Dielectric Separator,? is that it contains a high-voltage electrode con-figuration. The drum electrode consists of a series of coaxial parallel wires mounted on the outside surface of an Insulated cylinder. The screen electrode Is a wire mesh, quarter cylinder positioned outside and coaxially with the drum electrode. The drum electrode is placed in a liquid of dielectric constant K with the liquid level just above the drum's axis. The screen electrode is completely Immersed

Jan 1, 1981

By R. V. Ramani, P. M. T. White, D. Sutton

4.1 Introduction Using methods outlined in previous sections of this report, programs were written and/or obtained to: i) select best combinations of "a" and "k" for up to 8 different value parameters, ii) calculate available and unavailable ore tonnages and other statistics, and iii) produce contour maps of various parameter characteristics and available tonnages on a line printer. All the above programs are written in Fortran IV for execu¬tion on IBM 360/370 computers. 4.2 Calculation of Coal Reserves The Ore Reserve program suite consists of the following sections: (a) UNIT 1: This unit is a subroutine called by Unit 2 to determine values for "a" and "k" from the given data. (b) UNIT 2: These programs calculate ore reserves and are composed of a main program and several sub¬routines. In the following, their functions are abbreviated: i) MAIN - calls subroutines, reads run parameter variables, reads borehole data and interpolates grid node values for the area of investigation

Jan 1, 1974

By Wils L. Cooley, Herman W. Hill

'The electrical behavior of ground beds is often quite different from what would be expected based on experience with electric circuits. An explanation for this unique behavior is given, through means of an analogy, which should promote intuitive understanding of ground beds. The nonmathematical development of the text is complemented by an extensive appendix which describes the details of ground bed calculations. This work was supported by U.S. Bureau of Mines contract G0144138.

Jan 1, 1979

By Thomas Varley

"Concentration, ore-dressing, or the dressing of minerals are common terms used in metallurgy and indicate processes of separating valuable minerals from worthless gangue. It is understood, of course, that the products from such processes, being separated from the various minerals and gangue, are ready for commercial sale or for further treatment by smelters and refineries.Gravity concentration takes advantage of the difference in specific gravity of the various constituent minerals and gangue of waste material in the ore. The two most common forms of concentration by this means are jigging and table concentration. Jigs usually are used in the separation of relatively coarse material and the tables for the finer material, the line of division in general being about 20 mesh.There are mar factors to be considered .before a decision can be made as to what method would be best adapted to the successful treatment of an ore and only by careful experiments can this be determined. Among the important factors to be considered are. The nature of the minerals present, their physical and chemical relations to the gangue material, and the gangue material itself. Perhaps the most important is the number of minerals present and their relation to each other.Metals exist in ores in three principal forms -- sulphides, oxides or carbonates, and native. Concentration by gravity methods is in general best suited to sulphide ores, although in some places considerable success has, been obtained in the concentration of oxide ores by gravity methods."

Apr 1, 1920

By David White

The purpose of the studies that form the basis of this report was to learn from microscopic examinations of coal how far and in what ways the grouping of coal by types depends on differences in the kinds of plant material from which it was formed and on the condi- tions of its accumulation, or how far the special characters or qualities of coal of any type were determined by the nature and the state of the plant débris from which the coal was formed. The fact is almost universally accepted that beds of coal represent accumulations of vegetal matter in varying stages of preservation, with, as a rule, very small proportions of the remains of animal life. Mingled with the organic substances are different inorganic mineral sediments, which, together with the mineral matter originally con- tained in the plants themselves, constitute the "ash" of coal. The examination of coal shows that the kinds of ingredient plants range all the way from algee and fungi to large trees of various orders, and that these in turn vary in their own groups according to the depth and the nature of the water in which they grew and according to the other conditions of growth, such as moisture, temperature, soil, light, climate, and the competition of individuals. The species or kinds of plants and the numbers of each kind also differ greatly among themselves, not only during any one geologic period because of the changes of environment, but also from one geologic period to another, and it will be remembered that well-developed coal has been found in the strata of every period since the Silurian." Most geologists now agree that coal is transformed peat. True there is wide difference of opinion as to how the transformation has been accomplished and even as to whether coal started as such peat as is now found. Some writers insist that the higher grade coal, in its processes of development, never passed through geologic stages

Jan 1, 1913

By Joseph T. Singewald

The term "titaniferous magnetite" is used to designate those mag- netic ores of iron that carry more than 2 or 3 per cent of titanium. Large and easily workable deposits of these ores occur in different parts of the world, and have attracted attention for many years. Under present furnace practice, however, the smelting of these ores is both difficult and expensive, and for that reason they are not accepted by furnaces, so that the deposits are practically worthless. The problem of finding a feasible method of utilizing these ores has naturally been attractive, and numerous attempts have been made to solve it. Experiments to that end embrace two lines of investigation. The one that has been the more frequently tried is the elimination of the titanium from the ores, so as to make possible their smelting in the usual way. The other is the devising of a method of smelting by which titaniferous ores may be reduced as economically as are non- titaniferous ores. The former method involves a physical process, the latter a chemical process. The measure of success attainable by the first method depends entirely on the relations between the iron and the titanium in the ore. Views in regard to these relations have been divergent. Some investi- gators have believed the titanium to occur as a part of the magnetite molecule, in which case, of course, any process of mechanical separa- tion would be impossible. Others have believed that the titanium occurs as the mineral ilmenite, and that the ores are aggregates of magnetite and ilmenite. In this case a separation of the two minerals is theoretically possible. Magnetite is highly magnetic; ilmenite is nonmagnetic or only feebly magnetic. Crushing and magnetic con- centration should separate them. Numerous experiments in mag- netic separation have been made with various degrees of success, but rarely has more than a very imperfect separation been obtainable. In other words, some of the titanium exists in a separable form and some in an inseparable form, and the ratio between the two forms is

Jan 1, 1913