Search Documents

By F. N. Kissell

The applicability of the "direct method" for determining the methane content of virgin coalbeds was tested. Preliminary results indicate that the direct method, when applied to exploration cores, can be successfully used to estimate coalbed gas content and also approximately predict the total gas emission from a prospective mine located in the coalbed at the exploration site.

Jan 1, 1973

By McHenry Mosier

Mercury is one of the strategic metals the supply of which has been raised from critical uncertainty to more than enough for essential demands. Work by the Bureau of Mines has contributes substantially to increased production of mercury in the United States and to consequent accumulation of Governments stock. Other contributing factors were higher prices for mercury and Government loans to operators. The Bureau has undertaken 15 exploration projects, 13 of which have been completed. This work comprised 40,307 feet of drilling arid 35,082 linear feet of sure ace trenching and has indicated commercial ore containing 37,400 flasks of mercury and marginal ore contain¬ing 29,200 flasks - a total of 66,600 flask , equivalent, respectively, to domestic production at 50,000 flasks per year for 9 months , 7 months, and 16 months. Early in 1944, as Government stocks had become adequate, domestic production was gradually curtailed cancellation of Government contracts for the purchase of mercury and Government control of labor and operating supplies.

Jan 1, 1944

By D. N. Nilsen

The Bureau of Mines is investigating a method to recover Ni, Cu, and Co from low-grade domestic laterites through reduction roasting, leaching, sol-vent extraction, and electrowinning unit operations. The objective of this research is to develop processing technology that can convert low-grade domestic deposits containing critical metals into national reserves. As a part of this research, a solvent extraction system was investigated for the extraction of nickel and copper, followed by the separation and production of suitable electrolytes. Nickel and copper were coextracted from ammoniacal ammonium sulfate leach liquors (pH~9.5) with LIX 64N extractant in a laboratory-size mixer-settler continuous circuit. Three extraction stages resulted in >99-pct extraction of nickel, substantial copper extraction, and essentially no cobalt extraction from leach liquors. A crowd stage reduced the ammonia loading on the solvent by maximizing nickel loading. Residual ammonia was removed from the loaded solvent with a pH-controlled scrub. Nickel and copper loaded on the solvent were separated by selective stripping. Typical nickel strip circuit operation using electrolyte containing 90 grams per liter (g/l) Ni and 11.9 g/l H2S04 yielded >99.9 pct Ni stripped from the solvent in five stages. The copper loading on the recycled solvent was controlled in a copper strip stage using electrolyte containing 25 g/l Cu and 160 g/l H2S04,

Jan 1, 1981

By D. Harrington

The placing of much, sometimes practically all, of the burden of the expense of mine accidents on the shoulders of the mine operator by compensation laws, and the fact that the problem of protecting the life end limb of workers is now by public opinion largely if not wholly passed to each industry to solve (and present-day thought strongly supports the justice of both of these propositions), are forcing industrial organizations into accident-prevention. Work. This policy is being adopted not alone to protect the companies; in addition, executives alert to their opportunities and obligations are taking part in this work personally to protect themselves. The functions of industrial executives in accident-prevention work are becoming numerous and complex. Executives who are logical in their reasoning, quickly see that before a company can constantly ask or expect the workers to heed safety suggestions, the company and its officials must "put their house in order" by laying down a concrete, definite safety program. For mines this includes primarily adoption of a to a logical mining method, the installation of safe miming equipment and practice the netting forth in definite form (preferably do a printed pamphlet) of the company's minimum safety requirements, and the organization of its operating officials into an accident-prevention body. After the company has its own affairs so arranged that it can go to its workers with "clear, hands" in promoting a safety program, the real work begins; and this is especially applicable in mining.

Jan 1, 1939

Develop an improved downhole geophone system with enhanced signal/noise ratio for collecting cross-hole seismic data used in tomographic reconstructions. Background The Bureau of Mines is conducting research in the use of cross-hole seismic tomography for detecting and monitoring leach solution flow during in situ mining. This technique requires the use of a downhole seismic energy source in one borehole and a downhole wall-locking receiver (geophone) in another borehole separated from the first by the region to be investigated. Bureau research personnel chose a commercially available air gun for use as the downhole seismic energy source. Unfortunately, commercially available downhole wall-locking geophones that the Bureau tested were difficult to operate in the field, often unreliable and generally inadequate in terms of their signal/noise ratio. Therefore, research personnel began to experiment with an alternative down-hole geophone design that could be used to collect adequate data in a wide variety of borehole and cross-hole field situations. Approach An attractive alternative geophone design would be one that would incorporate a pneumatically operated wall-locking system. As an integral part of the Bureau's existing field system, a portable, high- pressure/low-volume air compressor would have sufficient capacity to operate the air gun as well as several small high-pressure pneumatic linear actuators. This approach was the simplest and most compatible with the research activities being conducted at the site.

Jan 1, 1991

By I. AITKENS

Quartz maintains a rather conspicuous position among gem stones , despite its being the commonest and, in its natural form, the most easily recognized of mineral substances . This prominence is due primarily to the extensive use of amethyst , which provides stones of the finest violet color , and also to the wide employment of yellow quartz ( citrine ) which is called topaz by jewellers and vies with the true topaz in color and brilliance . Unlike many less costly gem materials quartz is hard and durable .

Mar 1, 1932

By Jr. Dubaniewicz, Gregory M. Green, Kenneth L. Cashdollar

Laser-based instruments are used in areas where coal dust ignition presents a safety hazard. The National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory ~NIOSH, PRL! is conducting a study to help determine when an optical beam may be considered a potential ignition source in underground coal mines or coal storage facilities. Researchers conducted experiments to determine threshold igniting powers for Pittsburgh seam bituminous coal dust clouds using an 803 nm continuous wave laser. For fine sized coal dust dispersed in air, concentrations ranging from 600 to 2000 g/m3 were the most easily ignited. A heated layer of coal dust that deposited on the fiber tip during dispersion ignited the dust clouds. Minimum observed igniting powers for laser beams delivered by 200, 400, and 800 mm core fiber optic cables and directed into coal dust clouds were 2.0, 3.0, and 5.0 W, respectively. Threshold igniting power was proportional to beam diameter, and threshold igniting power density decreased with larger fiber diameters. Ignition delay times averaged 0.6 s and did not vary significantly with laser power under initially turbulent test conditions and with flammable targets. Comparisons are made with the results of other researchers.

Provide a full-scale test facility where the effectiveness of all types of subsidence abatement techniques can be evaluated under controlled conditions. Background Subsidence is ground movement resulting from the collapse of overlying strata into a mine void because of failure of the mine roof, mine floor, or support pillars. The failure may propagate to the surface and be expressed as a depression, cracks, or a sinkhole. The surface expression of such features may be delayed until long after mining has been completed. Subsidence has the potential to affect more land area than any other type of abandoned mine land problem. Subsidence also causes direct damage to real property, with significant financial loss and more importantly, presents a danger to public health, safety, and general welfare. Subsidence-related problems are considered to be one of the most important abandoned mine land issues. Backfilling of mine voids is the most common stabilization method used to abate subsidence and protect surface structures. Backfilling or placement of material is performed by hydraulic flushing or pneumatic stowing, using either in-mine or remote methods. The majority of the past subsidence abatement projects has been performed using remote methods from single or multiple boreholes. Other subsidence abatement techniques arc available. For example, various point support methods are used to protect small areas of the land surface and surface structures, without completely filling the mine void. These may be more appropriate under different conditions. Little documented information is available concerning the capability of the various backfilling methods for completely filling a mine void or providing long-term structural strength. Therefore, the Bureau of Mines developed a laboratory for controlled evaluation of backfilling technologies.

Jan 1, 1991

By F. M. Goodwin, John Campbell, G. W. Jones

"INTRODUCTION In previous reports 5 results were given of a manhole investigation carried out over a period from June 1929 to July 193C in cooperation with the Edison Electric Illuminating Co. of Boston. Mass., and during 1931 in cooperation with the Edison Electric Illuminating Co. of Boston and the Boston Consolidated Gas Co., to determine the general hazards of combustible gases and vapors in manholes and other underground openings owned by the Edison Electric Illuminating Co. and to develop methods of eliminating these hazards. These investigations have demonstrated that the detection, control, and elimination of combustible hazards in manholes can best be obtained by a close cooperation of the interested parties through a systematic and continuous inspection of manholes, under proper supervision.The investigation carried out during 1932 has been along lines similar to those conducted during 1929, 1930, and 1931 test crew consisting of two men, one an employee of the Consolidated Gas Co. and the other an employee of the Edison Electric Illuminating Co., was continuously employed during the year in the testing of gases in manholes served by the Edison system. The test crew was under the direct supervision of John Campbell, superintendent of the special service department of the Edison Electric Illuminating Co., and F. M. Goodwin, vice president of the Consolidated Gas Co.As in the previous investigations, all tests were numbered. The test-data sheets, on which the information regarding the tests was recorded, were prepared in triplicate, ono copy going to the Edison Co., one to the gas company, and the third to the Bureau of Mines at Pittsburgh, Pa. These test-data sheets were then filed (1) according to the town, (2) the street location, and (3) the manhole number; in this way a complete record of each manhole tested was immediately available. A typical test-data sheet was given in the 1931 report. These data sheets were found to entirely satisfactory and no changes were made during the 1932 investigation. The procedure of sampling manhole atmospheres, shipment of the samples to Pittsburgh, and method of analysis has been the same as that described in the 1931 report and need not be repeated here. Likewise, there has been no change in the method of calculation of explosibility of the samples analyzed or the use of charcoal filter tests given in appendix A."

Jun 1, 1933

By L. E. Schultze

[The Bureau of Mines conducted bench-scale studies to develop techniques for stripping tetravalent cerium from tri-n-butyl phosphate solutions. Experiments were conducted in a constant-temperature bath using beakers and mechanical stirring. Ninety-five pct of the cerium was stripped from a 50-pct tri-n-butyl phosphate 50-pct kerosene solution containing 0.18 M cerium in 15 minutes at 50° C using 0.11 M aqueous formaldehyde.]

Jan 1, 1974

By M. A. Lucas

The Bureau of Mines has developed a computerized mathematical model to predict the distribution of accessory elements throughout a metallurgical process. The model can be used to determine process conditions that effect better accessory element control consistent with continued high primary metal recovery. The model presented is specific for determining the bismuth distribution in lead smelting but can be adapted to most extractive metallurgical processes. Thermodynamic, kinetic, and process parameters form the base for the model. Its logic and structure are described in detail.

Jan 1, 1983

By H. M. Smith

In studying the chemistry of lubricating-oil fractions from so-called ?paraffin-base? crudes, one of the first requisites is a method for the separation and removal of waxy material. A method utilizing solvents for this purpose is described in this report, together with preliminary experiments with solvents that led to its development. The solvents actually used are secondary butyl alcohol, acetone, and mixtures of these.. Isopropyl alcohol was also studied. Preliminary Experiments In previous work on "intermediate-base" crude oil, following the work of Wyant and Marsh acetone had been used for laboratory separations of oil and wax. Then acetone was tried for the separation of the waxes and oils of "paraffin-base" crude, the volume of acetone required (80 parts to 1 part of oil) was found to be too great for large-scale work. For this reason the effectiveness of other solvents was studied; the separation by acetone, however, was used as a standard.

Jan 1, 1927

By M. E. Tyrrell

Magnesia spinel (MgO.Al203) recovered from dusting slags in the system MgO.Al203-2Ca0.SiO2 is in the form of single crystals most of which will pass 35-mash. This investigation was undertaken by the Bureau of Mines to evaluate the concentrates as a refractory raw material. Three specific types of refractory bricks were studied: (1) dense, (2) lightweight bubble, and (3) insulating. Test specimens ware fabricated 1 by dry pressing, fired to 1,675° C., and tested by procedures common to the industry. The concentrates produced a refractor, having satisfactory density and mechanical strength; however, spinal is sensitive to thermal shock and the possibility of producing a spall-resistant brick using aggregate of such small grain-size must be considered remote. Lightweight refractorias fabricated of spinel bubbles were the most promising of the types tested. They were 30 percent lighter in sight than the dense refractory, their mechanical strength was good, and definite superiority in thermal shock resistance was indicated.

Jan 1, 1962

By Everett A. Sondreal

Data are presented on the characteristics of lignites with emphasis on the composition and fusion properties of the ash. Differences in the analyses of commercial-grade lignites are related primarily to variations in moisture and ash contents. Lignite ash is generally characterized by high concentra¬tions of alkaline earth oxides and a greater tendency for retention of sulfur in the ash than higher-rank coals. Composition of ash varies significantly within and between mines. The differences within mines are significant for short distances and may be eliminated under certain circumstances by normal mixing occurring during mining. The sulfur in lignite averages 0.6 percent and is found primarily in the organic or pyritic forms with only a trace of the sulfate. During the stan¬dard laboratory asking procedures, from 60 to 100 percent of the original sul¬fur is retained in the lignite ash. Trace elements, such as uranium and germanium, in the ash from commercial¬-grade lignites are present in low concentrations, but others, primarily copper and silver, are present in specific samples in concentrations approaching those found in some commercial ores.

Jan 1, 1968

By H. C. Ko

The Bureau of Mines maintains an active program in thermochemistry to provide thermodynamic data for the advancement of mineral science and technology. As part of this effort, the standard enthalpy of formation at 298.15 K, ?Hf°, for 2CdO-CdSO4 was determined by HCI acid solution calorimetry to be -345.69 ±0.61 kcal/mol.

Jan 1, 1983

By B. Dimitriades

Data on smog-forming reactivities of exhaust aldehydes are scarce. Such data were obtained by irradiating in a smog chamber typical exhaust aldehydes, individually and in exhaustlike mixtures. Observed reactivity manifestations were rate of nitrogen dioxide formation (RNO2) and yields of oxidant, peroxyacetyl nitrate, and formaldehyde. Results showed that exhaust aldehydes vary widely in reactivity. Formaldehyde showed high RNO2 reactivity but low oxidant yield; benzaldehyde, [m]-, and [p]-tolualdehyde were totally unreactive when irradiated individually; [o]-tolualdehyde was reactive. In mixtures, benzaldehyde manifested reactivity in terms of peroxybenzoyl nitrate yield. Exhaust aldehydes as a group are judged to be as reactive as the exhaust olefin group. The importance of the aldehyde contribution to exhaust reactivity and methods for assessing such contribution are discussed.

Jan 1, 1971

By J. E. Murphy

The high-purity thorium metal was prepared by the Bureau of Mines from electrolytically produced thorium alloys. The thorium-chromium and thorium-manganese alloys were separated into the component elements by vacuum distillation. Chromium and manganese impurities remaining in the thorium metal after distillation at 1,850° C were <0.005 weight-percent. Removal of volatile impurities such as aluminum, calcium, magnesium, and lead was also accomplished.

Jan 1, 1969

By R. E. Hall

When the criterion for control of scale prevention on the evaporating surfaces is made the conditions in the concentrated boiler water, then this control becomes an exact operation amenable to an accuracy commensurate with all other operations in the boiler room. The responsibility in boiler water conditioning, however, includes more than clean surfaces. Corrosion in feed lines, economizers and the boiler is a function of the condition of the later, and must be controlled. Steam line and turbine blading deposits must be obviated by the system of conditioning. By the chemical treatment employed, the amount and character of noncondensable uses in the steam must be controlled in accordance with the intended use of the steam. All. in all, the responsibility in boiler crater conditioning ends not with the entrance of the water into the boiler but with the passage from the boiler nozzle of steam, the dryness and rarity of which are defined by the uses to be made thereof. A clearer conception of the scope of boiler water conditioning can be obtained by reference to a diagram of the surfaces (Figure 1) at which it functions. Consideration of this diagram leads to the following outline for the problems of boiler water conditioning: (a) Prevention of scale formation on surfaces (1) In contact with water but at which no evaporation occurs. (2) At which evaporation is occurring.

Jan 1, 1926

By William J. Campbell

The Federal Bureau of Mines provided five test materials--amosite, short-and long-fiber chrysotile, crocidolite, and nonfibrous tremo1ite--to the National Institute of Environmental Health Sciences (NIEHS) for studies on the biological effects of orally ingested asbestos-related materials. An inter-agency agreement between the Bureau and NIEHS made possible this program to characterize these test materials. The Bureau in turn received support through contracts with the Ontario Research Foundation for the milling of amosite and crocidolite, and with the University of Maryland for microscopic measurements. The five test materials, which were supplied in quantities of 960 to 1,200 pounds each, were characterized by chemical-instrumental analysis for elemental composition, surface area, density, X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, mineralogy, and particle size analyses. Particle size distributions were emphasized because of the current theories relating adverse biological effects to length-width characteristics of durable elongated particles.

Jan 1, 1980

By Charles L. Kimbell

In broadest overview, UN global industrial production indicators released and shown in table 2 suggest that the extractive sector of the world&apos;s mineral industry in aggregate registered a very slight upturn in 1991 relative to its 1990 performance. It also shows a continued rebound in the industry from the recessionary period of the mid-to late-1980&apos;s. These same indicators as calculated in late 1991, however, reflected a very minor downturn in extractive mineral industry operations between 1989 and 1990. This latter downturn represented a notable revision from the data reported in the immediate previous edition of this chapter, which suggested a tiny upturn. The apparent slight 1991 upturn in extractive sector industrial output generally was not mirrored in the performance of the processing sectors of the global mineral industry. Although the aggregate index for the chemicals, petroleum, coal, and rubber products manufacturers (see table 3) showed a notable gain in 1991, similar indices for nonmetallic mineral products and for base metals registered declines between 1990 and 1991. Examination of regional performance indices shows that the difficulties experienced in 1990 in maintaining output levels within the countries that formerly constituted the CMEA were reinforced by trends toward reduced gains in output levels, if not actual reductions in output, in several other areas. Generally speaking, the traditional developed market economy countries recorded downswings in overall industrial activity in 1991, particularly after midyear, whereas developing market economy countries logged gains. The developed market economy country downturns, however, were not nearly as significant as were the downturns recorded for the former centrally planned economy states - those that before 1992 were either constituent Republics within the U.S.S.R. or the latter&apos;s CMEA partners.

Jan 1, 1993