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By C. J. Johnson, C. J. Bise

"As the US coal industry moves into the next century, it is becoming more apparent that the effective application of new technology is the only way it can remain competitive in the energy marketplace. Examples of this emphasis are with us today in such diverse areas as face-ventilation and excavation-equipment applications. The focus of this new technology is directed toward improvements in health and safety, cost control, and productivity.Room-and-pillar mining accounts for approximately 68% of the nations underground coal production; this percentage is not expected to decrease markedly in the near future. As such, this paper analyzes the impacts of the changing technological climate on future room-mid-pillar operations by comparing a base-case section (current) to three scenarios incorporating new or emerging technology. A microcomputer-based comparative analysis will reflect the changes in section production and costs.IntroductionThe ultimate goal for any coal mining company is to effectively use its human and financial resources to maximize its profits through the extraction of its reserves. Although recent workforce reductions in the industry have resulted in a more efficient use of labor and increased productivity, there comes a point in time when further reductions in the numbers of workers in each operating section are impossible with existing equipment. For example, Farinelli and Bise (1987) found that labor cost constituted 62% - 73% of the cost per ton of coal at the mining section, with a minimum crew size. Thereafter, efforts to increase productivity must focus on more efficient mine plans and technology.The fact that an increase in productivity can be realized by reducing non-productive time (change-out and tram time) and converting it to productive time has been known and demonstrated for quite some time. What has not been demonstrated frequently is the quantification of the potential productivity increase of currently emerging technology or ""add-on"" equipment. It is one thing to be able to say that a piece of equipment will make an operation more productive, but it is another thing to be able to quantify the productivity increase that will justify the purchase of the new equipment. Not only is a financial benefit possible in room-and-pillar mining with an increase in productivity, but a decrease in the time necessary to develop a longwall panel can also occur.The purpose of this paper is an analyze the impacts of a changing technological climate on future room-and-pillar operations by comparing a base-case section (current) to several scenarios incorporating emerging technology. To do this, four cases will be developed. A base case, consisting of the typical manner in which continuous-miner sections are currently operating, is compared to three layouts incorporating: (1) flooded-bed scrubbers on radio remote-controlled continuous miners, (2)a continuous miner with side-mounted roofbolters, and (3) a continuous miner with side-mounted roofbolters used in conjunction with a continuous-haulage system."

Jan 1, 1989

By Thomas J. Peters

The King Mountain study area is centered about 120 air km northwest of Blackfoot, and 30 air km north of Arco, Idaho. The study area makes up the southern one-third of the northwest-trending Lost River Range--the highest mountain range in Idaho. The area is predominantly underlain by Paleozoic-age marine limestone and lesser dolostone, with a relatively small inlier of silica-rich, Ordovician-age quartzite. There are vast, unquantified resources of these industrial minerals present; however, special markets need to be developed for these resources which are near enough for transportation costs to be competitive. Five prospects were found in the study area; however, only one, the Elbow quartz silica prospect, contains resources and current claims. There has been no mineral production in the study area.

Jan 1, 1993

By R. V. Lundquist

This report describes results of tests on the desilication of solutions resulting from the leaching of lime-soda sinters. Desilication was accomplished by heating the solutions in an autoclave. A liquor relatively free of silica was obtained after 30 minutes of heating at 200 p.s.i.g. in the presence of lime. The addition of lime improved desilication, but the rate and efficiency of desilication was effected by the quality of lime used. The optimum quantity of lime for effective desilication was about 6 grams per liter. A lesser quantity gave poorer desilication, and a greater quantity increased the alumina loss without improving desilication. The alumina loss was approximately proportional to the lime added. A complex structure, called artificial noselite in this report, was the only silica bearing compound detected in the desilication precipitate. Other compounds present were Ca(OH)2 (calcium hydroxide), CaCO3 (calcium carbonate), and Ca [A1(OH)6]2 (hydrated tricalcium aluminate). Sodium carbonate in the leach liquor retarded the formation of the calcium aluminate; hence it decreased the alumina lost to the precipitate. The extraction of alumina from aluminum silicate materials by the limestone soda-sinter process has been investigated by the Bureau of Mines for many years. The process consists of the following major operations: Blending the aluminum silicate with limestone and soda ash in such proportions that dicalcium silicate and sodium aluminate are formed on sintering; leaching the sinter in a carbonated caustic solution to extract the soluble alumina; purifying the leach liquor by the precipitation of soluble silica (this precipitate is designated desilication precipitate in this paper); precipitating alumina trihydrate from the purified liquors by carbonating with carbon dioxide gas; and calcining the trihydrate to alumina. Commercial grades of

Jan 1, 1962

By J. M. Stuve

Low temperature and high-temperature calorimetric measurements were made by the Federal Bureau of Mines on high-purity samples of Re02(s) and Re03(s) to determine heat capacities and enthalpies. The temperature range of heat capacity measurements was 5 to 310 K for Re02 and 8 to 309 K for Re03. High-temperature enthalpy measurements alone were determined for pure Re207(s,1). The derived standard entropies are S°298 = 11.43±0.01 cal/deg mole for Re02(s) and S298 = 16.55±0.02 cal/deg mole for Re03(s). High-temperature enthalpy equations expressed in calories per mole are as follows: Re02 (s) , H-H298.15 = 16.002T + 1.600 X 10-3T2 + 3.522 X 105T-1 - 6,095 (298 to 1,400 K); Re03 (s) , H-H298.15 = 20.293T + 3.238 X 10-3T2 + 3.950 X 105 T-1 - 7,664 (298 to 1,000 K); Re207 (s) , H-H298.15 = 38.437T + 10.309 X 10-3T2 + 4.315 X 105 T-1 - 13,824 (298 to 413 K); Re207 (s) , H-H298.15 = 30.181 + 17.713 X 10-3T2 - 10,612 (413 to 600 K) ; Re207 (1) , H-H298.19 = 66.101T - 10,092 (600 to 700 K). Gibbs energy of formation (?Gf°) data and related functions over the temperature ranges investigated are tabulated for the three oxides.

Jan 1, 1976

By Harold Bailie

The purpose of this Bureau of Mines report is to furnish information on mining practices applied to flat-bedded fluorspar deposits in southern Illinois. It presents new and improved operating procedures and specialized techniques applicable to deposits of this type. All of the operating mines of the Ozark-Mahoning Co. in this area have been opened by vertical shafts which connect with levels consisting of haul-age ways, stopes, and loading stations. The stoping practice used locally called room and pillar, is open stoping with pillars left at different distances and diameters. To facilitate haulage and drainage, the mines are worked from openings turned off the main haulage drift on a grade to conform with the dip of the ore beds. The ore is predominantly fluorspar with smaller amounts of galena and sphalerite that contain traces of cadmium and germanium. The principal gangue minerals are limestone, calcite, shale, barite, and sandstone. The rock hardness ranges from relatively soft shale to hard, abrasive sandstone.

Jan 1, 1960

By Raymond B. Ladoo

Silica , or silicon dioxide , ( Si0, ) , occurs in a free state chiefly as quartz , but hydrous silica ( amorphous silica carrying a variable amount of combined water , 2 to 13 per cent ) , occurs as opal , flint , diatomaceous earth , tripoli and so on . Quartz is found in many forms , the most important of which are ; As vein quartz; quartzite ; sandstone ; silica sand and gravel ; as crystals or crystalline grains , masses or aggregates in igneous rocks such as granites , dicrites and pegmatites . Commercially silica is used in many ways , but ordinary uses of sand and gravel are so well known that they will not be considered here .

Jan 1, 1922

By W. C. Wahl, M. M. Fine

Leonardite , a naturally occurring , partially oxidized form of lignite with a high content of humic acids , was investigated as a binder for iron ore pellets . Although insoluble in original condition , leonardite forms watersoluble salts with good binding properties when treated with certain alkalis such as sodium hydroxide . Soluble leonardite imparts excellent dry strength to pellets , but green strength is somewhat lower than that obtainable with bentonite . However , green strength can be improved by adding a small amount of calcium hydroxide to the leonardite - concentrate mixture . Leonardite binders were used successfully on three of the four different concentrates tested .

Jan 1, 1964

By W. W. Adams

The quantity of explosives sold in the United States in January, 1931, for domestic consumption, amounted to 368,100 kegs (9,202,500 pounds) of black blasting powder, 4,610;000 pounds of permissible explosives, and 16,533,000 pounds of high explosives 'other than permissible. These figures are based on reports received by the United States Bureau of Mines, Department of Commerce, from nearly all manufacturing companies, and include an estimate of sales by several companies that do not furnish monthly reports. Reports actually received from manufacturers showed soles of 365,977 kegs of black blasting powder (consisting of 220,892 kegs of granular powder and 145,085 kegs of pellet powder), 4,687,900 pounds of permissible explosives, and 15,496,152 pounds of high explosives other than permissible. Sales in January, 1931, were smaller than in January, last year, the decreases being 14 per cent for black blasting powder, 19 per cent for permissibles, and 17 percent for high explosives other than permissible. Sales in January 1931 when compared with soles in December 1930, show increases for all three classes of explosives as follows: 2 per cent for black blasting powder, 16 per cent for permissible explosives, and 7 per cent for other high explosives.

Jan 1, 1931

By W. W. Adams

[The quantity of explosives sold in the United States in January, 1931, for domestic consumption, amounted to 368,100 kegs (9,202,510 pounds) of black blasting powder, 4,810;000 pounds of permissible explosives, and 16,533,000 pounds of high explosives other than permissible. These figures are based on reports received by the United States Bureau of Mines, Department of Commerce, from nearly all manufacturing companies, and include an estimate of sues by several companies that do not furnish monthly reports. Reports actually received from manufacturers shored sales of 365,977 kegs of black blasting powder (consisting of 220,892 kegs of granular powder and 145,085 kegs of pellet powder), 4,687,900 pounds of permissible explosives, and 15,498,152 pounds of high explosives other than permissible. Sales in January, 1931, were smaller than in January last year, the decreases being 14 per cent for black blasting powder, 19 per cent for permissible, and 17 per cent for high explosives other than permissible. Sales in January 1931 when compared with soles in December 1930, show increases for all three classes of explosives as follows: 2 per cent for block blasting powder, 16 per cent for permissible explosives, and 7 per cent for other high explosives. PERMISSIBLE EXPLOSIVES: Of the 4,687,900 hounds of permissible reported sold during January, 97 per cent was used for coal-mining operations, Including 32 per cent for anthracite mines and 65 per cent for bituminous mines. The following Staten were the largest users of permissible explosives daring January: Pennsylvania, West Virginia, Illinois, Alabama, Kentucky, Indiana, and Utah. Their combined sales represented 89 per cent of the entire sales reported for this class of explosives.]

Jan 1, 1931

By Lee M. Manna

Approximately 10,000, 10-Ton, 4 wheel, 2 truck, coal mine cars are in general service in U. S. Mines. None are equipped with an automatic braking system. Very few are equipped with hand or parking brakes. The report lists major manufacturers of the car and develops estimate as the percentage represented. It complies physical specification of cars of major car manufacturers, and develops a composite clearance diagram. It then discusses a pneumatic system employing truck components for an automatic system that could be used as an add-on unit. The components are listed and priced and a schematic circuit is developed for the system. Recommendations as to future programming are made.

Jan 1, 1976

By J. C. Holtz

Since 1937 the Bureau of Mines has conducted investigations to provide the technical information necessary to guide the safe use of diesel engines underground in the United States. Coincident with the beginning of the technical study, a survey was made of State regulations pertaining to the use of internal-combustion engines underground.3/ At that time it was found that owing to the known hazards of gasoline locomotives, many States had enacted legislation or regulations limiting or prohibiting their use underground. Some of this legislation prohibited, or could be interpreted as prohibiting, the use of any type of internal-combustion engines in underground workings. After World War II diesel-powered equipment was introduced underground in many States, and pertinent questions are received frequently by the Bureau of Mines about the regulations that permit such applications. Because it was known that new and revised regulations had been made effective in some States in the nearly 20 years that have elapsed since the previous survey,3/ the Bureau decided that a review of the latest regulations in the leading mineral-producing States would be a valuable source of information for those engaged in the production of minerals as well as others. Accordingly, where feasible, this report includes abstracts of State laws and regulations as they affect the use of internal-combustion engines underground, particularly diesel engines. The substance of comments from State officials also are included when these appear to be helpful to interpretation of the regulations.

Jan 1, 1957

By P. J. Colbassani

Samples of mine atmospheres collected by Federal coal-mine inspectors during their inspections and investigations of coal mines, in accordance with provisions of the Federal Coal Mine Safety Act (66 Stat. 692; 30 U. S. C., sees. 451-483) are analyzed routinely by chemical methods at Bureau of Mines laboratories. When samples collected in open workings of nongassy coal mines at points not less than 12 inches from the roof, face, or rib contain 0.25 percent or more methane, the act requires the operator, during operation of such mine, to comply with the provisions of sec. 209, Title II, of the act, which pertain to gassy mines. The methane con-tents of such samples are determined by a physical method based on infrared absorption spectrometry to provide an independent check on analytical results obtained by chemical methods. This information circular describes the equipment and procedures used by the Bureau for determining low concentrations of methane in coal mine atmospheres by infrared absorption spectrometry. ACKNOWLEDGMENTS The authors are indebted to Dr. R. A. Friedel, Chief of Spectrometric Section, Branch of Coal-to-Oil Research, Bureau of Mines, for suggesting the analytical method and for furnishing valuable advice and assistance, and to J. A. Queiser of his staff for making exploratory measurements by this method; to Dr. M. G. Zabetakis of the Division of Explosives Technology for his assistance during the conduct of preliminary experimentation; and to L. B. Berger, Chief, Branch of Health Research, under whose guidance the equipment was procured and the work conducted.

Jan 1, 1958

By B. A. Rogers

The problem of obtaining enough manganese for use in the manufacture of steel appears likely to recur when international relationships are disturbed and to become serious at any time when the United States is cut off from its customary supply. Some idea of the problems that an e under war conditions may be obtained from a description given by Ellicott3/ in 1918 before the American Iron and Steel Institute. This condition arises because in normal times there is an economic advantage in importing available high-grade foreign ores to the neglect of our own less satisfactory resources. That considerable low-grade manganese ore and a much smaller amount of high-grade material are available in this country is well known from geological surveys 4/ and has been confirmed by Bureau of Mines investigations. Locations of the various deposits are indicated in figure 1. The possibility of greatly expanding domestic production was actually demonstrated from 1913 to 1918, when the annual production of manganese from domestic ores rose from about 4 percent to approximately 35 percent 6/7/ of the total consumption of ferromanganese and spiegeleisen. In idea of how domestic production compares with total consumption in the United States can be obtained 1 from figure 2, taken from the Minerals Yearbook8/ for 1970. Assuming that it is possible to increase production of manganese ores sufficiently to supply all our needs, such a program presumably would require 2 or 3 years, and the cost of production would certainly rice considerably, for some time at least. For

Jan 1, 1941

By Charles L. Harness

Fifty years ago, the belief that "fillers" were added to paints for the sole purpose of diluting and cheapening the pigment may have been justified; but paint technology has made tremendous progress since that time, and today both the manufacturer and the consumer know that the judicious use of fillers may add desirable properties to a paint that cannot be introduced in any other way. A growing respect for these accessory materials has led to the use of the more euphemistic term "extender." The names "extender" and "filler" are to a considerable degree synonymous. The newer term, "extender," is adopted in this paper, though it is actually no more descriptive than the older name. Stewart's3/ definition of extender is: "A cheap pigment, usually of an inert type, used to extend or increase the bulk of a paint, thus reducing its unit cost. Extenders are also used to adjust the consistency of a paint and to let down colored pigments of great tinting strength. The use of an extender in a paint does not necessarily mean the resultant product will be inferior. In fact, extenders sometimes, improve -certain characteristics of a film." All extenders are not cheap, as, for example, wet-ground mica and diatomite. Research in the, use of extenders (also sometimes called "inerts") has been one of the host active branches of study in the paint field; and many thousands of dollars have been spent in establishing the physical and chemical characteristics required of various natural mineral extenders for numerous paint formulas

Jan 1, 1943

By S. W. Parr, T. E. Layng

There is presented below the results of experiments made on six samples of Utah coals furnished through the U. S. Bureau of Mines , under an agreement dated June 16th , 1920. The details of all values for all runs are tabulated and presented herewith . Clear The samples, consisting of approximately 150 pounds each, were received at the University of Illinois , on June 15 , 1920 , and are listed as follows : Creek , Wattis , Castle Gate , King , Standard , and Aberdeen . The proximate and ultimate, analyses of the various ccals from that region , representing all the types included in these samples , have already been made by the Bureau of Mines , and are available . * Similar determinations were also made on the particular samples forwarded for purposes of these experiments . The results obtained on the coal as received did . not very in any material feature from the values reported by the Bureau, they are shown in Table 1. It is of importance to note only that the oxygen content is uniformly high , namely approximately 9.5 to 11.5 per cent of the as- received coal , while the oxygen - hydrogen ratio is also high, being on the average approximately 2 ( oxygen) to 1 ( hydrogen) .

Sep 1, 1921

By D. W. Frommer, M. M. Fine

Laboratory investigations have produced flotation concentrates contain- ing 91 to more than 92 percent titania, with fair recoveries, from the Christy property, Hot Spring County, Ark. The titanium-bearing ore on the Christy property occurs in a quartz-clay- iron oxide mineralization, which contains, on the average, about 6.0 percent TiO2, chiefly as the mineral brockite; brookite and rutile are different crys- talline forms of titanium dioxide. Recent work by the Bureau of Mines has shown that titanium chloride can be produced readily from the rutile-type mineral by reduction with coke fol- lowed by low-temperature chlorination. Metallic titanium is in turn derived etallic from the chloride by the Kroll process .

Mar 1, 1952

By R. R. Nothdurft

The internal friction of eight single crystals of magnesium with orienta-tion ranging from 10° to 84° was measured at 33.5 kc and 272° C, and the results were interpreted in terms of the pinned-dislocation model proposed by Granato and Lucke. Results show that the strain-amplitude-dependent decrement varies with orientation in a manner predictable by the G-L model. Different values of strain-amplitude-independent decrement were observed at different orientation angles, but correlation with the theory was not conclusive. Problems and steps for further study are discussed.

Jan 1, 1965

By V. A. Marple, K. L. Rubow

"4.1 IntroductionIn previous chapters impactors have been described as useful instruments for classifying particles by their aerodynamic diameters and for measuring particle size distributions. These impactors can be used most reliably if the user has some understanding as to how the impactor classifies particles and what parameters are important in this classification process. This understanding can best be obtained by a theoretical inspection of inertial principles.This chapter reviews the most recent theoretical impactor work and the latest theoretical efficiency curves. Procedures are then given for using these efficiency curves in the design and evaluation of cascade impactors. Finally, several examples are given comparing theoretical and experimental efficiency curves, pointing out when the theory can be used with great confidence and when the theory should be used only as a guideline.Due to the rather simple principle of operation of an inertial impactor (i.e., the impingement of a jet of particle-laden air on a flat plate) the impactor readily lends itself to theoretical analysis. Three notable works in the early 1950,s were those of Davies and Aylward (1951), Davies et al. (1951), and Ranz and Wong (1952).Davies and Aylward (1951) used a method of conformal mapping to obtain an analytical solution to Euler's equation for the flow of a frictionless fluid through a rectangular impactor. Numerical calculations were then carried out whereby the equations of motion of the particles were solved in a stepwise manner, leading to a determination of the efficiency curves. Since this theory assumed potential flow, the effect of Reynolds numbers on the characteristics of the impactor could not be determined.Ranz and Wong (1952) used an approximate flow field to calculate the efficiency of both round and rectangular nozzle impactors. In the vicinity of the stagnation point, the flow field was assumed to be that of frictionless stagnation flow. Here, the resulting equation of motion for the particles was found to be in a form similar to equations for free vibration with viscous damping. Therefore, the known solutions of the vibration equations were applied directly to the problem and the efficiency curves calculated. This solution technique, however, could not take into account the various geometric variations such as the jet-to-plate distance in the determination of the efficiency curves.The work of Ranz and Wong (1952) was later modified by Mercer and Chow (1968) and Mercer and Stafford (1969) so that the rather simple flow fields of Ranz and Wong (1952) could be used to account for various jet-to-plate distances. The same techniques, however, were used to determine the impactor collection efficiency curves."

Jan 1, 1986

By R. E. Lindstrom

A study of ion-exchange resin crosslinkage and eluant flow rate, resin-bed shape, and addition of separating ions to feed stock was undertaken to determine their effect on the separation efficiency of ion-exchange on bastna-site-rare-earth elements. Results show that 12-percent divinylbenzene (DVB) crosslinkage resin is detrimental to separation efficiency at flow rates over 2 to 5 ml./min./sq. cm.; whereas, separation with 4-percent DVB crosslinkage resin is relatively unaffected by flow rates between 2 and 10 m1./min./sq.cm.

Jan 1, 1959

By John C. Holtz

"INTRODUCTION Information on the gaseous products from the detonation of explosives has been obtained in two ways. In the first, the atmosphere in mines is analyzed after blasting, and in the second, the gases found after detonating an explosive in a testing apparatus are analyzed. The Bureau of Mines, in a cooperative research 3/ that compared data obtained in the field with those obtained in the testing station, showed that the results were not in entire agreement. The production of carbon monoxide was found to be governed chiefly by the oxygen balance of the explosive, but the production of oxides of nitrogen did not change in so simple a manner. Because of the increasing interest in correlations between the composition of the explosive and the production of toxic gases, it seemed desirable to continue the investigation.PURPOSE OF INVESTIGATIONAs field tests are both time consuming and expensive and as field results are affected by factors that are not always under control of or clearly evaluated by the operator, the purpose of this investigation is to develop a testing-station procedure that will reproduce the gaseous products quantitatively under known conditions analogous to those that may be expected in the field. In addition, the factors affecting the formation of toxic gases, particularly oxides of nitrogen, will be studied,"

Apr 1, 1940