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In order to reduce waste and improve resource conservation, mine planning, and development, the U.S. Bureau of Mines is investigating the effects of multiple seam interactions associated with longwall coal mining. Field investigations were conducted at a mine located in Boone County, WV, where a longwall panel was operating subjacent to room-and-pillar workings in an overlying seam. To assess the effects of overlying workings on longwall headgate stability, the Bureau gathered various geotechnical information at this minesite. Headgate pillars and entries were instrumented and monitored to study their behavior during side-abutment loading as the longwall panel approached and passed beneath the overlying room-and-pillar developments. The two operations are separated by 800 ft of interburden, and although interactions between operations separated by this distance are uncommon, geomechanical measurements indicate the occurrence of an interaction. These measurements show that convergence on the headgate entries was most adverse subjacent to barrier pillars in the overlying mine. Pillar measurements indicate that side-abutment pressure increases were slightly greater than predicted values. Several factors related to both geology and mine design, believed responsible for this large interactive distance, are discussed.

Jan 1, 1990

By Oliver Bowles

The United States Bureau of Mines has within its ranks a group of engi- neers who are engaged in working out quarry problems, the solution of which will be of general benefit to the industries involved. The problems undertaken are approached in a systematic and thorough manner, all the evidence for and against any proposed change or new development being collected as carefully as an attor- ney would prepare his data on an important case. Unlike the attorney, however, the Bureau engineer does not take sides; his judgment is based entirely and in- partially on the array of facts presented. In order to gain the desired infor- mation he visits many plants, consults with the leaders in the industry, works out experiments in his laboratory, and supplements this information with a stu- dy of all available literature already published on the subject in any part of the world. As an engineer who has for eight years conducted such inquiries in the stone industry, I propose to discuss the Bureau of Mines viewpoint; and it may be of interest to consider with me in a brief and general way the engineer's method of looking at quarry problems, and some of the results attained through past and present labors. While the Bureau has conducted no investigation directly for the crushed- st one industries, two years of investigative work at cement-plant quarries, and work now being conducted at lire-plant quarries, has a very direct bearing on the problems of the crushed-stone industry, since stripping, drilling, blasting, loading, and transportation are similar in many respects in all stone quarries. The results of cement-plant quarry investigations are to be found in Bureau of Mines Bulletin #160. (b) Two short papers on lime-plant quarry problems have been issued in mimeographed form as Serial #01 (c) and Serial 3 (d).

Jan 1, 1923

By N. S. Dalal, X. Shi, P. M. Gannett

"Chromates are known to induce tumors (1, 2), mutations (3), and DNA damage (4-6). However, the underlying biochemical mechanism(s) is (are) not fully understood (6). Recent studies have indicated that hydroxyl (·OH) radical may play an important role (7-11). The mechanistic studies of Cr(Vl)-related ·OH radical generation in biochemical systems have shown the reaction of a Cr(V) species with hydrogen peroxide (H20 2 } through a Fenton-like mechanism to be one of the important steps (9-11): Cr(V) + H20 2 - Cr(VI) + ·OH + OH-. (1)In biological systems the Cr(V) species are generated via the reduction of Cr(VI) by a variety of components, such as microsomes (12), mitochondria (13), mitochondrial electron transfer complexes (14), and at least three flavoenzymes (glutathione reductase (GSSG-R),3 lipoyl dehydrogenase, and ferredoxin-NADP+ oxidoreductase) (9, 15, 16). In the case of flavoenzymes, Cr(V) formation is accompanied by the reduction of molecular oxygen ( 0 2 ) to H20 2 • The Cr(V) species then reduces H20 2 to generate •OH radicals and Cr(VI) (16).To understarid the mechanism by which Cr(V}-generated ·OH radicals cause cytotoxicity, Aiyar et al. (8) investigated the reaction of Cr(VI) and H20 2 to generate ·OH radical and its reaction with 2'-deoxyguanine (dG) to form 8-hydroxy-2'-deoxyguanine (8-0HdG}:"

Mar 1, 1992

By C. W. Schultz

The vapor pressure of manganese in equilibrium with a series of liquid iron-manganese alloys was determined by the carrier gas method over a broad range of alloy composition. From these data the activities of manganese in the iron-manganese system were calculated. The system appears to be ideal.

Jan 1, 1966

By R. W. Huber, R. C. Wiley, V. C. Petersen

"Three arc- melted ingots, two of a t itanium-7 percent manganese all oy and the third of unalloyed titanium, were forged and rolled into 3/ 4-inch plate; comparative data were obtained on these processes. The finished plate, part of which was used by the Naval Bureau of Ordnance, was tested for mechanical and other properties.These properties were correlated with sponge purity, forging technique, rolling temperature, and cooling rate from the rolling temperature. For the alloy material, transformation data were obtained, and their age-hardening characteristics were studied. The temperature-impact relationship was established for rolled sections from all three ingots.INTRODUCTIONArc -melted ingots of unalloyed titanium and a titanium-manganese alloy were fabricated into plate under closely controlled conditions by personnel of the Metals and Alloys Section, Physical Metallurgy Branch, Bureau of Mines, College Perk, Md. This program was cosponsored by the Naval Bureau of Ordnance. Bureau of Mines interest lay in correlating the processing procedures with the mechanical properties of the finished plate.Considerable data have been published recently on constitution diagrams and properties of titanium-manganese alloys in genera1. 3/ 4/5/6/ However, little if any correlation between processing schedules and end results has been published, particularly with respect to the present commercial production of the proprietary titanium manganese alloys . Several factors in the production of titanium and titanium alloys have a pronounced influence on the physical and mechanical properties of the finished product: (1) The degree and nature of impurities in the base materials, ( 2) the amount of impurities introduced during the melting cycle and their distribution, (3) the homogeneity of the alloy, (4) forging, (5) rolling, and ( 6) final heat-treating cycles. All of these item£ are important from a metallurgical standpoint in producing the desired end properties in the metal."

Mar 1, 1955

By P. M. Gruzensky

Several experiments have been carried out in efforts to evaluate qualitatively a variety of electrolytes for refining bismuth. Most extensive work was done with the basic tartrate, hydrochloric acid, and hydrofluosilicic acid electrolytes. Deposits that are smooth and adherent can be obtained from these three electrolytes if low cathode current densities are employed. All three electrolytes were effective in purifying crude bismuth considerably, with additional purification indicated in each instance by a reelectrolysis step. With the basic tartrate electrolyte best results were obtained when the electrolyte was at 40° C, and contained at least 100 grams of bismuth per liter, An apparent disadvantage was depletion of bismuth from this electrolyte, causing the deposits to become spongy and nonadherent.

Jan 1, 1956

By M. R. Geer

Traditionally, fine coal is more troublesome than the coarser sizes at every step of the coal-preparation process--screening, cleaning, dewatering, and drying. Therefore the present trend toward a higher proportion of fines in the run-of-mine product, brought about by changes in mining practice necessitated to increase productivity, has added greatly to the task of preparing coal for the market. One of the more difficult and costly problems involved is that of recovering fine solids from the washery water. These fine solids should be recovered in the interest of conservation, and they must be removed to provide recirculating water of proper quality. If there is a plant effluent, it must meet increasingly stringent requirements against stream pollution. Vacuum filtration has been used for years at a few plants to recover the extreme fines, but its additional cost discouraged general adoption until recently. Now, with growing emphasis on better solids recovery, filtration is becoming more widespread. Many coal slurries filter readily, giving high cake rates and clean filtrates. Others, however, particularly those containing either a high proportion of material finer than 200-mesh or an appreciable amount of clay, are much more difficult to filter. Many of these refractory slurries can be rendered more filterable by flocculation. A previous report of Bureau of Mines research dealing with flocculation alone was published in 1940.5/

Jan 1, 1959

By Oliver Bowles

Calcareous rocks, of which the principal varieties are marble and lime¬stone, are used extensively for building and ornamental purposes. Onyx and travertine, subdivisions of these groups, are sufficiently distinctive in origin and use to merit separate classification. The purpose of this paper is to define the terms "onyx" and "travertine" and to describe the occurrences and uses of the materials bearing these names. ORIGIN AND CHARACTER Confusion exists in the use of the word "onyx." True onyx is a banded chalcedony, a form of silicon dioxide related to jasper, agate, and flint. Calcium carbonate is commonly deposited from solution in successive layers of varying color closely resembling onyx, and for this reason such calcareous rock is also called "onyx." To distinguish the calcareous from the siliceous

Jan 1, 1940

By Ann G. Kim

Acid drainage from underground coal mines and coal refuse piles is one of the most persistent industrial pollution problems in the United States: This Bureau of Mines report reviews the acid mine drainage problem generally and describes research currently underway to combat it.

Jan 1, 1982

By David E. Fogelson

One model each of three different makes of portable displacement seismographs was calibrated on a shaking table capable of 5,000 pounds of force, Calibration tests were conducted in the frequency range of 5 to 200 c.p,s, and in the amplitude range of 0,002 to 0.05 inch peak-to-peak, The seismographs were tested under two mounting conditions: (1) The feet of the instrument were bolted to the shaking table, and (2) the feet were resting on emery cloth affixed to the table, The results of these tests show that, in the frequency range of 5 to 40 c.p,s, and for vibration levels less than 0.2 g, the magnification for all three instruments is constant with input level but varies slightly with frequency. For vibration levels greater than 0.4 g. and for frequencies greater than 40 c.p.s., the magnification of all three instruments shows large variations with frequency and amplitude of table motion.

Jan 1, 1962

By Foster Fraas

This Bureau of Mines report describes a method for separating minerals at magnetic susceptibilities within the diamagnetic susceptibility range. The maximum feed rate varies directly with the square root of the lower limit of permissible susceptibility, while the lower limit of permissible susceptibility varies inversely as the square of the magnetic field strength. Minerals may be separated at particle sizes smaller than possible on conventional dry-type magnetic separators.

Jan 1, 1969

By John M. Gomes

Two molten salt systems were evaluated as electrolytes for the repetitive recovery of tungsten from tungsten oxide (W03) made by calcining commercial-grade ammonium paratungstate. Using a sodium chloride-sodium fluoride-potassium aluminum tetrafluoride electrolyte at 800° C, 1 pound of 99.8 percent tungsten was recovered for each 2.7 kilowatt-hours of energy consumed. The metal contained 1,100 ppm carbon, was in dendritic masses of spherical grains, and had an apparent bulk density of 5.41 g/cm3. T ngsten of 99.9 percent purity was won from a sodium pyrophosphate-sodium tetraborate-sodium chloride electrolyte at 1,000° C; 6.0 kilowatt-hours of energy was consumed for each pound of metal recovered. The metal contained 120 ppm carbon, was in dendritic masses of hexagonal acicular crystals, and had an apparent bulk density of 7.25 g/cm . Each metallic impurity--aluminum, calcium, copper, iron, nickel, and silicon--in the two tungsten products was 16 ppm or less.

Jan 1, 1966

By A. C. Johnson

This report describes exploration, development, and exploitation methods, and summarizes costs at the Stormy Day mine, which was discovered in 1941. Several shipments of tungsten ore were made in 1944 to the Metals Reserve Company, Salt Lake City, Utah. The purchase of tungsten by the Federal Government, which began in 1951, stimulated interest in tungsten, and a successful program of exploration with participation of the Defense Minerals Exploration Administration (DMEA) indicated enough ore to warrant development of the property. Development work comprised drifting, crosscutting, and raising. Shrinkage stoping was used for mining the ore. Operations were suspended in October 1956, when the Federal Government terminated its purchase program. Total production of the mine was approximately 20,000 tons of tungsten ore. INTRODUCTION This information circular is one of a series, prepared in cooperation with various mining companies and published by the Bureau of Mines, relating to methods and costs of equipping and developing mining properties in the United States.

Jan 1, 1958

By Dhanesh Chandra

[The U.S. Ucparunent of tlIe III LeriOr, Bureau of 1?Ilnes, lnta dcvcltil- (I a m.?tl,nd to extract nickel, i:ob.tll and IlIIicr Valuc:l,1, mrl?tl., lrom I.ow grad:, dumusI it Inlet itc.: :isin;; a rarb-i mnnnxid:: reducl.iun and ,innnonln/mumonlum sull,h.Ito Icitcll Col lowed by solved. evil let foil and clot tr:,winnfu,;. 'I 'o rain bcLtur undcI'sLandin;; uI the producLs reduced rind leached with the s;:Item, the liureau of t?Ilite; was enf,ngod In a 1 uinL sl.utly IIt1I the Uuttvcr ltc~:c:n-ch LnstiI-IL-. 'I'hr'ut;;h C(Im:drlod ahplit I¬L ion:; of a rotnbIW)L11nl ill eleu Lyon :utJ uplical inicrnscopy, cle trun beau micru,inal?;st?s and X-r.iv tcchnitlaes, Lhc factors jilt] ucncing low nickul e::lracl.on yLrids Iron, ccrlnin l;tteritos wul the hcuefhe al yCferL front addil.I:un u1. r:u)plowt' ruug,ounus and halides have bucn rrvealod. IL leas ht'en shown their nt nliJcrate Lion terlperuLuri's (5S0°C - 6501C) Lhe 111LACl extraction ylolds were low hccausc of the futmetlt-m of rufrill t,urv sillc:Ite compicxcs during ciii lit Hi [hut COOL.tlu sig nlficnnt anutunls of nickel .Lrui LhaL arc resistant Lu discolullull it, a su6r.C?quent ammnnlIca1 Jcaeh. 'This formation ill rulracLorv rnngtieves is altrlbuU?d Lo the prc.srnCV of aluauinum combined with c.ilicun jn addlt.lon In tnnl;neni~im in I.lic Lalerites, Iligb exII.Ictlon yields were oblalneJ when none or only a few I ,fraCLot' e, were InrmeJ. Hit s;intc rcfrarlnry cowl, Icxc5 also lend Lo surround Ow IaaIIiable meI.allle iron-IIIcI:el :iILoy CIUSisling ill the mau'ix, tIll: rrhv nreveu)Ling cuntacr ,Itlt LI5U Jeacl: solution; this, huwrvcr, ran ho ovu:rcoml by At ti itlon .111.11 retieCtiun. 'I'hc eIIcc l of prr.reJIctlun .,Ill itivi's vucli i's lye iii', ',udlum "Ill orIde, hv,Irogrn CIIInrILIC, etc., and Lht? 1111,Lre:InrLlI'll he'e:tleg un Lbe cxLt,icLitin are also iilsr.ussod 111 Lhe rcl,olt.]

Jan 1, 1979

By G. L. Oldright

The data in this paper were collected at the Trail smelter of the Consolidated Mining & Smelting Co. of Canada, Limited, through the courtesy of S. G. Blaylock, vice president and general manager; James Buchanan, smelter superintendent; George Murray, assistant smelter superintendent; and the staff members given in Paper XI, Report of Investigations 3243. INTRODUCTION This paper is the thirteenth of the series on Smelting in the Lead Blast Furnace, and the third of the series on Handling Zinciferous Charges. Tyro other papers have been written on the Rate of Descent of the Stock Column, and Formation of Accretions. These are Reports of Investigations 2963 and 3094, for the Tooele plant and the Bunker Hill plant, respectively.

Jan 1, 1934

By W. M. Mark

This investigation was undertaken to develop methods to improve the quality of titanium sponge produced by the Bureau of Mines modification of the Kroll magnesium reduction process. Research revealed that by systematic elimination of detrimental impurities introduced with the raw materials and by improved handling and processing techniques, high-quality ductile titanium with a hardness of less than 110 B.h.n. (Brinell hardness number) can be produced consistently. This improvement was accomplished by helium (or argon) stripping of residual atmospheric and other dissolved gases from the titanic chloride, preliminary dehydration of crude titanium sponge, and careful regulation of the titanium tetrachloride (TiC14) feed rate to the reactors.

Jan 1, 1960

By V. R. Miller

The Bureau of Mines developed and evaluated a detecting and sorting device to separate the copper-bearing portion from the barren portion of Michigan native copper ore in the minus 4- plus 1-inch size range. Small-scale sorting tests were also conducted on minus 1- plus 1/2-inch material from the Centennial No. 6 mine, using a previously developed system that was modified to increase sensitivity. Results showed that, with the added sensitivity, 85 to 90 pct of the copper in the minus 1- plus 1/2-inch material could be recovered in about 50 to 60 pct of the fraction. Sorting tests on minus 4- plus 2-inch and minus 2- plus 1-inch fractions from the Centennial mine were conducted with the large sorting system. Results showed that 86 to 93 pct of the copper was recovered in 43 to 64 wt-pct of the sorted fractions. Combining of concentrates from the two fractions resulted in a recovery of 90 pct of the Popper in 55 pct of the weight. The composite concentrate contained 2.40 pct copper, and the tailing analyzed 0.33 pct Cu; the head sample assayed 1.46 pct Cu.

Jan 1, 1978

By M. A. Elliott

Diesel-powered haulage equipment has recently been tested and approved for permissibility by the Bureau of Mines for use in mining in the United States. Achievement of this advance in safety involved extensive studies, both in the testing station (2, 3, 20, 21, 22, 23, 24, 25, 26, 27)3/ and in the field 1, 4, 13, 30), of the operating characteristics of diesel engines in relation to the toe of such engines underground. The results of these studies formed the basis for establishing the requirements that should be met by diesel-powered haulage equipment approved for permissibility. Considerable interest has been manifested in the development of diesel-powered haulage equipment fur mines. The purpose of this paper is to retrace briefly the course of this development and to answer such questions as: What is the history of the use of diesel engines underground? Why has the Bureau of Mines been interested in the development of diesel-powered haulage equipment for use in mines?

Jan 1, 1953

By John W. Buch

In 1947, a Korfmann universal shearing machine was installed in a mine in the Southern field of the Pennsylvania anthracite region. The machine was obtained from Germany by the Bureau of Mines after the close of World War II as a part of a program of experimental work to increase the output and lower the cost of anthracite, which the Bureau of Mines initiated in 1944 when an agreement was made with an anthracite-producing company for use of one of the company's mines as a testing ground for certain mechanical equipment procured or developed by the Bureau. A major objective is to develop a mechanical mining method that will increase the rate of advance and reduce the coat of development of coal gangways in steeply pitching seams. In addition to the time to be saved in driving these openings by machine, it is felt that further economies will be affected by making it possible to concentrate producing sections into smaller compass and that savings will ensue in supervision, maintenance, and time required for mining a section. A higher percentage extraction also is an objective. Test work covered by this report was concentrated on the power characteristics, maneuverability, effectiveness, and general qualities of the Korfmann machine in cutting coal, the cutting tests representing the first use of a machine of this kind in steep-pitch mining in the United States.

Jan 1, 1951

By Jr. Norman

Thermoelectric properties of depleted uranium selenides and tellurides were investigated from room temperature to 700 C. Several depleted uranium monoselenides and monotellurides were doped with selected cationic and anionic materials to determine the effect of impurity additions on the thermoelectric properties. The undoped uranium selenides and tellurides were semimetallic conductors exhibiting low Seebeck coefficients and electrical resistivities. Partial or complete degeneracy was in evidence, indicating a charge carrier energy distribution similar to that in a metal. Doping increased the Seebeck coefficients of the uranium monoselenides and monotellurides; however, the corresponding change in the power factor in the figure of merit was small because of the increase in electrical resistivity.

Jan 1, 1965