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By B. R. Mohal, F. F. Aplan, S. Chander

"ABSTRACTThe wetting behavior of coal has been determined in the presence of nonyl and octyl series of nonionic surfactants containing polyethoxy groups of different sizes. The wetting behavior was determined by a modified Walker technique and contact angle measurements. The results show that the wetting rate of coal varies with coal rank, structure of the hydrocarbon chain and number of ethoxy groups in the hydrophilic group of the surfactant. A close relationship has been observed between the wetting rates and the short-time advancing contact angles.INTRODUCTIONNonionic surfactants are used in many applications to improve wettability of solids. They can be used as dispersing agents [ 1 ] or dust suppressants [ 2-5 ] and to control the flotation, flocculation, filtration and flowability of particulates. This study was undertaken to study the effect of a series of nonionic surfactants on the wetting behavior of coal. Two series of surfactants, namely, ethoxylated nonyl and octyl phenols were used. The nonyl phenol series contains a linear hydrocarbon chain containing nine carbon atoms ( CH3( CH2 )8-C6H4,- ( OC2H, ) n, where n is the number of ethoxy groups) . The octyl phenol series contains a branched hydrocarbon chain containing eight carbon atoms ( ( CH3 ) 3CCH2C ( CH3)2-C6H4- ( OC2H4) n ).Initial wetting rates — modified Walker techniqueWalker et al. [ 6 ] developed a sink test to determine the wettability of coal particles. In this technique, coal particles are dropped individually onto the surface of surfactant solutions of different concentrations, and the most dilute concentration in which coal would sink ""instantaneously"" is determined. This technique is a variation of a procedure initially developed by Draves and Clarkson [ 7 to determine the effect of surfactants on wettability of cotton fibers. In this procedure commonly known as the Draves test, the concentration of a surfactant required to give a 'sink time' of 25 s is determined.Other investigators have used slight variations of the Walker method to study the wetting of fine particles [ 8-12 ] , by measuring the time for wetting a given amount of powder. There are differences in the manner in which the time of wetting is measured, however. Some investigators measure the time for the last trace of coal to disappear [ 8,11 ] whereas others determine the time for the vast majority of particles to sink [ 10 ] . Some investigators report a wetting rate [ 11 ] which is a value calculated on the basis of the time for the 'last traces of particles to sink'. The differences in choice of criterion for wetting can result in different values for wetting rates as illustrated in Fig. 1 which is based upon our measurements of the amount of powder wetted as a function of time. The procedure for wetting rate measurements is described in the next section. The technique in which time for disappearance of the 'last traces of particles' is determined gives the smallest value for the wetting rate, while the technique in which the time for wetting of the 'vast majority' of particles is determined will give intermediate rates. The terms 'last traces of particles' and 'vast majority of particles' are usually not defined explicitly and can lead to large differences in wetting rates measured by different investigators. Since our measurements show that the wetting rates for an assembly of powder decreases with time, we have used the initial wetting rates to compare the wetting behavior of coal in solutions of different surfactants."

Mar 1, 1989

By John B. Umhau

[This !m-i~!.al survey giver, statistice.1 data res;?~dirf ~:rimay ard ?eco~- dqr or scmn tin used in thL: United St,ztas by industries an? incluclcz d;ta on stop&apos;ics, ~urchares, ard plnrt losr.c.5. It is :i ml:anwe of consq~tion in terms of fir.is1icd -prcd.~cts nz6.e iry initid ti11 Sabric:,.torc,, that is, aon- cerns that purchzse virc,in zni s~col~d&apos;l~y i.i.5 ti:; 01&apos; tin c;cra.. rav materi,als ar,d co:lrrert them into !ror?ucts such F!: ti:i plz.te, ~lloyr;, and. c?hemic?ls; comy~nias ;~urchn.&apos;.ii~; alloys, ch:rr.ic,~l::, or tin vl?.tc fcr furthcr a:mflzc- ture ?rc: ~-.f>t i~ci~~dcd. Tilit r~lqe:;tionrr::ire submit tod to consunern ar,nt:incd no dofinition of rnr.oncl.:ryr me$.-i; but, ovrirq to ti~i-: a~counti~ procedure used s.l~o~c-:t 1&apos; thu scrnn hac i~-.rtergol:e ch?rri?~ of ovinerzhip or titlo, thc rc!coverod t! n !its b~en i-c<;,r(it.!rj L.S r,e~3r;d:q met.1. Tbv tin content ~f ]

Jan 1, 1938

By John B. Umhau

[&apos; is ann.tal surve:&apos; gives sta.tistical data regC:ll~dirg rims.ry and feCOA-dUTY or ~cra:p tin used in thL United States by industries anc. includcc dc..ta l&apos; is ann.tal surve:&apos; gives sta.tistical data regC:ll~dirg rims.ry and feCOA-dUTY or ~cra:p tin used in thL United States by industries anc. includcc dc..ta ]

Jan 1, 1938

By John C. Machisak

Statistical data on injuries in the metal and nonmetal industry of the United States first became available to the Bureau of Mines by collecting reports from the operators for the calendar year 1911. Since then reports have been collected annually. The present bulletin, covering the calendar year 1954, is the 31st publication (1933-34 was published as Bulletin 398) containing statistical data on injuries at metal and nonmetal mines and related plants, and it 1s the first such bulletin to be published since 1942. The last publication was Bulletin 461, Metal and Nonmetal-Mine Accidents in the United States, 1942. The unpublished statistics for 1943-53 may be found in the Appendix of this bulletin. The Bureau of Mines is authorized to collect data on injuries and related employment at metal and nonmetal mines, but there is no Federal law that compels operators to submit such information. Therefore, all materials submitted are voluntary responses to the Bureau&apos;s requests for information. The figures presented herein may not be complete for the entire industry, nevertheless, every effort has been made to make them so, and the data given are believed to be representative of the hazards to which metal and nonmetal workers are exposed. Moreover, the figures are comparable as between States-which is significant in view of the lack of uniformity among the States as regards classes of plants covered by State laws, classes of injuries covered by State reports, and other factors that tend to make it impracticable or impossible to compare the injury experience of one State with that of another or comprehend the relative importance of the various causes of injuries in the industry as a whole.

Jan 1, 1957

By Robert L. Lagace

This final report documents the work done by Arthur D. Little, Inc. (ADL) on behalf of the U.S. Bureau of Mines, Pittsburgh Mining and Safety Research Center (PMSRC) , on Contract H0122026 (which began in August of 1971) . Under this contract ADL provided technical assistance to the Bureau on a task basis on virtually all aspects of the Bureau&apos;s programs related to present and planned emergency and operational communications and miner location systems for underground coal mines. The work consisted of in- dependent investigations, analyses, experiments, breadboard and prototype hardware development, workshops and technology transfer seminars on mine communications, and on-going evaluations and guidance related to the Bureau&apos;s contracted programs on electromagnetic noise, mine communications systems, and trapped miner location. This final report documents the work in two volumes, Volume I, "Emergency and Operational Mine Communications," and Volume II, "seismic Detection and, Location of Isolated Miners." The Tables of Contents of both Volumes are included in each Volume.

Jan 1, 1974

By W. R. McDonald

The Bureau of Mines, U.S. Department of the Interior, conducted small-scale field tests on acidic copper tailings as part of its effort to develop, improve, and demonstrate technology for stabilizing mining and mineral-processing wastes. Two successful demonstration revegetation plots were established on an abandoned copper-tailings pond located on public land adjacent to Holden Village, Wash. The tailings were neutralized with treatments of either dolomitic lime or limerock and fertilized with processed sewage sludge and/or commercial fertilizer. Excellent plant growths covering 70 and 24 percent of the surface were achieved on 1/8-and 1-1/2-acre test plots planted in 1973 and 1974, respectively. Regar brame, Tegmar intermediate wheatgrass, and tall wheatgrass provided the best plant growth and surface coverage. The target pH of tailings neutralization was 6.8; however, good plant growth occurred in areas where the soil pH ranged from 2.9 to 5.8.

Jan 1, 1978

By L. D. Tracy

The first study of this subject hits been made in Illinois, but as opportunity affords, similar studies will be made in other States. It is hoped that the data obtained will assist the coal-mining industry to standardize the forms of leases, and so avoid some of the abstruse and ambiguous clauses which slay be found in many of them and the consequent liability of costly litigation. In some of the publications of the Illinois Mining; Investigations prepared under a cooperative agreement with the U. S. Bureau of Mines, the Illinois State Geological Survey and the Engineering Experiment Station of the University of Illinois, the coal areas of the &apos;State have been divided into eight geological districts, each district being treated separately. This report covers District No. VI of that classification, and it is hopped that studies of the other districts will be completed in the near future and similar results published.

Jan 1, 1926

By R. V. Ramani

This report, Volume I of the seven-volume Final Report on the U. S. Bureau of Mines research contract no. G0254030 titled Application of a Total System Surface Mine Simulator to Coal Stripping with the Pennsylvania State University provides an executive summary of the purpose and scope, objectives and results of the research. The remaining volumes of the Final Report, listed below, describe in detail model development, input and output documentation and the three case studies. Under the project, an existing surface mine simulator, Open-pit Materials Handling Simulator (OPMHS) was modified and extended for application to surf ace coal mining. In addition, two equipment selection models, and a cost model were also developed. Volume II: OPMHS User&apos;s Manual Volume III: Equipment Selection Models Volume IV: Surface Mining Cost Model Volume V: Application of OPMHS to an Illinois Mine Volume VI: Application of OPMHS to a South Eastern Ohio Mine. Volume VIII: Application of OPMHS to a South Western Mine.

Jan 1, 1978

By L. C. IlsLey

Minin,g Qr col-cu.ttint till:I chines are 1?;\i9ng the _m9t wideiy .used de1sses ()f mining equipment.· These 1T:.i:1Chines ,.--re practicaily t-tl\·operc1_ted eiyher_by compressed .iir or by electric. ·motors. According to &.ta• compiled _ from the 122. issue COAL CATALOG\JE. OJMEINED WITH; OOAL "FIELD 'pf!:fC'TOTl1, bf 7,088. mnes from which reports were obttiined there -are 3895 mines that u.se coal-cutting eql;lipmen:ts,, 'f'hi report lists 20,031: r.ct:lchines, 17,&75 being operated by·elct:i.c.m<;>_tors··:r;id :the remtiinder by compressed i.r motors,· ,-. · ', .. . · .. ··, .. _ ,· .,, .. .. . . . . . : ; "'l t:: On tl.Ccou-nt .. of the wide· use of coc:11-cutting -.:i"cliine_- any Stat!;ls have issued regulationa as "to their operation dnd be to safety precautions that.should be observed J especially in gaseous mines.

Oct 1, 1922

By Ivette E. Torres

For a study such as this, which summarizes and amalgamates much information collected, compiled, and utilized by the numerous U.S. Bureau of Mines country specialists and branch chiefs for inclusion in their country and regional reports that comprise the five other sections of 1992 Minerals Yearbook-International Review, it is clearly impossible to cite all sources of information used in its presentation, but some recognition is due. Generally speaking, this study and its related detailed studies on countries and areas would be much more difficult, if not impossible to complete, without the efforts of the personnel of our counterpart national mining and geological agencies throughout the world. Information that they collect, compile, and then publish, either in their own volumes or those of central statistical agencies in their countries, are the foundations on which this work rests. Thus, our appreciation is expressed to the multitude of persons employed by these agencies for their contributions.

Jan 1, 1994

By Howard C. Turnage, Dana T. Updyke

An evaluation was made of one of several improved underground communication systems sponsored by the U.S. Bureau of Mines. The system evaluated was installed in a typical metal/non-metal room and pillar mine and utilized UHF repeaters connected to a unique distributed antenna and passive reflector system which provided mine-wide communications. A microprocessor controlled data collection system was assembled and installed for the evaluation. Data consisting principally of times and durations of messages and identities of the originating transceivers was collected between February and August of 1982 (6 mos.). Analysis of the data shows that the principal benefits are reduction in time required for unscheduled maintenance and repair, enhancement of safety, and better coordination of production activities. A cost benefit analysis shows a net benefit over cost, although it is also concluded that the capacity of the system is greater than can be justified by current activity in the mine.

Jan 2, 1983

By Liming Yuan

Three-dimensional computational fluid dynamics (CFD) modeling is conducted to simulate spontaneous heating in a large-scale coal chamber with a forced ventilation system. Spontaneous heating is modeled as the low-temperature oxidation of coal using kinetic data obtained from previous laboratory-scale spontaneous heating studies. Heat generated from coal oxidation is dissipated by convection and conduction, while oxygen and oxidation products are transported by convection and diffusion. The water vapor transfer and the effect of heat of wetting are not modeled. The CFD model is validated by comparing simulation results with test results from U.S. Bureau of Mines experiments conducted in the coal chamber. The model predicts lower temperatures in the early stage but agrees well on the induction time for spontaneous heating. The effects of airflow rate and order of reaction on the spontaneous heating process are also examined. The calibrated CFD model is found to be useful for predicting the induction time for spontaneous heating in underground coal mines.

Jan 1, 2009

By Harry W. Campbell

U.S. Bureau of Mines investigation; identified no mineral resources or evidence of mining activity in the Sheep Divide RARE II area. A deposit 10 mi (16 km) southwest of the area contains copper and silver minerals in the Triassic Wild Sheep Creek Formation which probably underlies basalt lava flows covering the study area. Abundant basalt in the area can be crushed and used as aggregate, but suitable deposits closer to markets are widely available No sand, gravel, coal, oil, gas, or geothermal resource, were Identified. INTRODUCTION Location and Access The Sheep Divide RARE II area [10 mi (16 km) west of the Snake River] encompasses 7,100 acres (2,800 ha) of the Hells Canyon National Recreation Area in the Wallowa-Whitman National Forest. Enterprise, Oregon, is located 23 air mi (37 (m) west of the area. Peripheral access is provided by the highway from Joseph to the community of Imnaha, Oregon, then south to the study area by the graveled Upper Imnaha Road (fig. 1).

Jan 1, 1983

By Jerry E. Olson

In 1986, at the request Of the Bureau of Land Management, the U.S. Bureau of Mines studied the central portion, encompassing 20,727 acres of the 32,261-acre Badlands Wilderness Study Area (OR-005-021) in order to evaluate its identified mineral resources. The study area is located in Crook and Deschutes Counties, OR, about 12 miles east from Bend. No mineral resources were identified. The area studied is underlain by Tertiary and Quaternary basalt flows which are largely covered by a veneer of sand and silt. No mines, prospects, or mineralized areas occur within or near the study area, but some sand and gravel has been removed from alluvial deposits at the east and west sides of the area. Slab lava of marketable grade and quantity was not found in the study area. None of the study area is of current interest for geothermal resources, but the eastern third of the wilderness study area is leased (1984) for oil and gas.

Jan 1, 1987

By Bryan F. Ulrich

If resin-grouted roof bolts are not installed correctly, mine roof reinforcement can be affected, and roof falls can result. A bolt installation variable that is readily controlled by the mine operator is annulus thickness. The objective of this U. S. Bureau of Mines investigation was to study the effect of annulus thickness variations on the integrity of 3/4-in-diam resin-grouted bolts. Forged-head test bolts, 2 and 1 ft long, were installed in concrete blocks that had been drilled with 1-, 1-1/8-, 1-1/4-, 1-3/8-, and 1-1/2-in-diam bits. Standard pull tests were performed; then the concrete was broken away from the bolts so that grout mix quality could be inspected. It was found that the optimum annulus thickness is 1/8-in (l-in-diam drill hole), and as annulus thickness increases from the optimum, there is a corresponding decrease in grout mix quality, effective grout ratio, and axial stiffness.

Jan 1, 1989

By W. L. Cornell

The Missouri Pb ores are the only domestic Co resource being mined and processed for other metals; therefore, they present a viable short-term opportunity for Co production. Lead, zinc, and copper concentrates are produced from the ore. The Cu concentrate can contain up to 30 pct Co and the Pb concentrate up to 15 pct Co. Since Co is detrimental to the processing of the Zn concentrate; the remainder of the Co is rejected to the tailings. The tailings can contain as much as 50 pet Co originally present in the mined ore. Researchers at the U.S. Bureau of Mines have successfully tested on a continuous basis a process that recovers a bulk sulfide concentrate from mill tailings. The concentrate contains up to one-half of the Co and from 50 to 90 pct of the Pb, Zn, and Cu. Concentrate weight represents 10 pet or less of the total tailings.

Jan 1, 1989

By Paul W. Jeran

Subsidence was monitored by the U.S. Bureau of Mines over the ends of longwall panels operating in the Pittsburgh, Kittanning, and No. 2 Gas Coalbeds of the northern Appalachian Coal Basin. The final subsidence over the finishing ends of three panels in the Pittsburgh Coalbed are compared with the subsidence measured over the rib at these panels. The characteristics of subsidence are different. At Mine A, data over the start of a longwall panel shows similar characteristics to the subsidence measured over the rib. Subsidence over the fmishing ends of panels in the Kittanning and No.2 Gas Coalbeds are also different from the subsidence over the rib. The use of a subsidence prediction model based on data gathered over the rib of a panel will not yield accurate results if it is applied to the finishing end of a longwall panel. Acceptable results may be obtained along the centerline over the starting end of a panel.

Jan 1, 1991

By Kenneth B. Higbie

PRESIDENT LYNDON B. JOHNSON announced at midyear that the test flight of the A-It plane, the world&apos;s first super-sonic aircraft capable of flying 2,000 miles per hour, was made possible by "the mastery of the metallurgy &apos;and fabrication of titanium." Not all of the contributions made by the mineral industry in 1964 were acknowledged so widely. Yet the contributions were significant as the search continued for new and improved methods for providing metals and mineral products to meet the ever-expanding requirements of the world economy. This chapter reviews only a few of the metallurgical developments that resulted from U.S. and foreign research efforts. MINERAL BENEFICIATION Up-to-date theory &apos;and practice in the mineral ,Processing field in 1963 involved subjects such as autogenous grinding, high-intensity magnetic separation, and mill control by computers. These subjects were fully discussed at the Seventh International Minerals Processing Congress held in New York City during September.

Jan 1, 1965

By Gary P. Sames

This report discusses some practical applications of a geotechnical investigation conducted by the U.S. Bureau of Mines that can help mine operators meet revised Federal regulations in their roof control plans. The investigation, designed to characterize roof conditions near the coalbed outcrop in drift coal mines in eastern Kentucky, revealed that weathered stress-relief joints near outcrop are crucial ground control factors in the region. The joints&apos; origin and character were determined through underground mapping of many joints in coal mine roof and detailed observations and measurement of joint trends and physical characteristics in widely separated strip mine highwalls and roadcuts. This resulted in an understanding of stress-relief-joint patterns and the effect of various rock types on the intensity of weathering in the joints. That information is used in this report to show how stress-relief joints contribute to roof failure and how, through improved roof support and mine planning, safer roof support plans can be developed.

Jan 1, 1992

By J. L. Ambs

The U.S. Bureau of Mines (USBM) Diesel Research Program emphasizes the development and evaluation of emission control devices to reduce exposure of miners to diesel exhaust pollutants. Studies by the USBM have shown that diesel exhaust aerosol (DEA) contributes a substantial portion of the respirable aerosol in underground coal mines using diesel equipment not equipped with emission controls. The USBM and the Donaldson Co., Inc., Minneapolis, MN, have developed a low-temperature, disposable diesel exhaust filter (DDEF) for use on permissible diesel haulage vehicles equipped with waterbath exhaust conditioners. These were evaluated in three underground, mines, to determine their effectiveness in reducing DEA concentrations. The DDEF reduced DEA concentrations from 70 to 90 pct at these mines. The usable life of the filter ranged from 10 to 32 h, depending on factors that affect DEA output, such &apos;as mine altitude, engine type, and duty-cycle. Cost per filter is approximately $40.

Jan 1, 2010