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By Joan Weinberg

The real gross national product (GNP) expanded by 2.3% during the second quarter, down from the anomalous 4.4% growth rate in the previous 3 months. If the expansion continues through October, it will have lasted 5 yr and become the second longest in 40 yr.2 As in the first quarter, improvement in U.S. exports played a role in the continuing--albeit slow--growth. More than 2 yr of declines in the dollar relative to currencies of other industrial countries have contributed to a slight reduction in the trade deficit in real (volume) terms, as real net exports of goods and services rose $1.9 billion (table 1). Exports grew a strong 12.1% while imports, which had fallen the previous two quarters, rose 7.4%. Manufactured goods and petroleum products accounted for most of the second quarter import increase. The American Petroleum Institute estimates that the volume of crude oil and refined products imports in the first half of 1987 surpassed those in the same period last year by 7.5%, reflecting falling domestic production and higher than expected demand. Expenditure on durable goods--those that last at least 3 yr-by both consumers and producers also contributed to the second quarter expansion. Personal consumption of durable goods rose 9.0%, after having fallen the two previous quarters. Motor vehicle purchases accounted for most of the second quarter increase and the first quarter decrease. Sales of automobiles surged in the last quarter of 1986, as consumers rushed to capture the sales tax deduction that was eliminated on January 1. Sales fell in the first quarter of 1987, but have now moved closer to the trend line exhibited in the first three quarters of 1986. Automobiles accounted for half the 0.8% July gain in retail sales, and two-thirds of the 1.4% June gain. Producers durable equipment purchases also rose this quarter, accounting for the increase in nonresidential fixed investment.

Jan 1, 1987

By Robert E. Barieau

In the design of plants to separate helium from natural gas, it is necessary to estimate the enthalpies of the various streams at various positions in the process. This Bureau of Mines report surveys the various methods that have been used to determine enthalpies and gives information on the organizations with such capabilities. The minimum information required for developing an enthalpy diagram is presented, and the relative merits of the various methods are discussed. It is concluded that methods that require no mass flow rate or energy measurements are to be preferred.

Jan 1, 1965

By Robert E. Barieau

In the design of plants to separate helium from natural gas, it is necessary to estimate the enthalpies of the various streams at various positions in the process. This Bureau of Mines report surveys the various methods that have been used to determine enthalpies and gives information on the organizations with such capabilities. The minimum information required for developing an enthalpy diagram is presented, and the relative merits of the various methods are discussed. It is concluded that methods that require no mass flow rate or energy measurements are to be preferred.

Jan 1, 1965

1. Proposals were submitted to the Western Administrative Center of the US Bureau of Mines, Denver, Colorado on 30th December, 1974 and Contract No J 0255003 was awarded, the effective date being 8th May, 1975. Dames and Moore, Denver, are associated with PD-NCB Consultants in regard to environ-mental problems, surface mining practice and legislation in US. BACKGROUND TO THE STUDY 2. Under the threefold pressures of -increased domestic fossil fuel demand -increased value of domestic energy resources -increased demand for environmental protection and safety

Jan 1, 1976

By Max L. Glenn

As part of its goal to minimize requirements for mineral commodities through conservation and substitution, the Bureau of Mines conducted research to develop molybdenum as a potential substitute for superalloys containing the strategic and critical materials, nickel, chromium, and cobalt. Since molybdenum requires protection from oxidation at high temperatures, several complex oxides of the spinel and perovskite structure were investigated to determine which possessed the greatest potential for use as oxidation-barrier coatings. Two spinels (MgCr204 and MgA1204) and five perovskites (BaHfO3, YCrO3, NdCrO3, BaZrO3, and LaCrO3) were selected for testing. Various high-temperature prop¬erties that are important for oxidation-resistant coatings were examined, including diffusion rates of oxygen and molybdenum, recession (vaporization) rates, hardness, erosion resistance, sinterability, reactivity with molybdenum, and ease of application. From the evaluation of high-temperature properties, two spinels (MgCr204 and MgA1204) stand above the other oxides as possible coatings for molybdenum. However, laboratory coatings of MgCr204 at 1,360° C (2,480° F) are equivalent or inferior to currently available MoSi2 coatings; laboratory coatings of MgA1204 may be comparable under limited conditions to currently available MoSi2 coatings at the same temperature.

Jan 1, 1979

By John B. Gayle

[The coking time exerts a Considerable influence on the throughout of a coke oven, and for this reason a large number of papers dealing with the relation between coking tine and the different operating variables have been published. Although all of the factors known to ink influence the coking time have been studied, agreement leas not boon reached on several questions, 3/4/ and it appears worthwhile to evaluate any data that become available during investigations of the carbonizing properties of various oafs and coat blends, this report, therefore, includes a Study of the relation between coking lime and flue temperature and represents the second phase of overall investigation ion of factors influencing the coking time in slot-type ovens.]

Jan 1, 1956

By Christopher Mark

This proceedings volume contains papers presented at W U.S. Bureau of Mines (USBM) technology transfer seminars on New Technology for Longwall Ground Control. These seminars were conducted in Washington, PA, on April 12, 1994, and Denver, CO, on May 10, 1994. The papers herein describe several new, highly practical USBM technologies now available for ground control in longwall mines, including lie Coal Mice Roof Rating (CMRR), cable bolts, the MULSIM/NL model, and the Wood Crib Performance Model. Other significant topics addressed include longwall panel layout, coal pillar design, horizontal stress in longwall mines, roof support selection for gate entries, and ground control monitoring.

Jan 1, 1994

The contractor examined L.T. White's Patent No. 3524680 and, finding it in need of engineering refinements, proceeded with a conceptual design of a variable wall mining machine. The contractor then proceeded to assess the feasibility of the variable wall mining machine measured against the criteria specified by the U.S. Bureau of Mines. The feasibility was judged from a physical aspect, a health and safety aspect, and an economic aspect. The Variable Wall Mining Machine was judged to be feasible on all three aspects provided that certain specified practices were adopted. Description The specifications and design and performance parameters of the Variable Wall Mining System as conceptualized are summarized in Tables I and II. The system consists of a side-cutting auger operating in a string of identical 12 ft. sections, along a 500 ft. retreating longwall face. In addition to the 41 identical sections, there is a special drive and discharge section at the head gate.

Jan 1, 2012

By George H. Holmes

The water situation in Nevada mineral and related industries is described in this report. It contains information on the sources and adequacy of supply to current operators, requirements and uses, quality and costs, geography, hydrography, precipitation and evaporation characteristics, and Nevada water laws. Also, information is given on the water requirements of one public utility powerplant, and the source and consumption of water in four major cities. Water distribution at 24 operations is shown on schematic waterflow diagrams. The mineral industries of Nevada in 1962 used 8.6 billion gallons of new' water and reused 3.8 billion gallons for a total usage of 12.4 billion gallons. The copper industry was the major water user. The 1962 value of all mineral production in Nevada was $85.5 million. The large amount of water required to maintain thin high production is obtained principally from ground-water sources in alluvial valleys and the permeable rock formations of some mountain ranges. Some water is also obtained from perennial streams and springs. Sources of water utilized by existing industry ire near most mineral industry operations; however, seven companies are forced to pipe water distances ranging from 2 to 8 miles. Although water supplies of presently operating companies are adequate at most operations, several companies resort to large-scale reuse of water as a matter of conservation and economics. Acquisition of water by new operators is possible but takes considerable negotiation. Water rights, surface and underground, are controlled by the State. The quality of the water is satisfactory for most purposes. Analyses of 19 samples, listed in the appendix, show the range in water quality at various plants throughout the State. Costs of delivering new water to current operations range from 2 to 26 cents per 1,000 gallons with an average of 10 cents per 1,000 gallons for power and maintenance. No firm costs for recirculating water were available; estimated costs range from 1.5 to 2.5 cents per 1,000 gallons. The mineral-product value of the entire Nevada mineral industry in 1962 was equivalent to $10 per 1,000 gallons of new water and $26 per 1,000 gallons consumed. Projection of the 1962 water requirements of the Nevada mineral industry indicates that the demand For new water will increase from 8.6 billion gallons in 1962 to 11.9 billion gallons in 1980, a 43-percent increase. Water requirements in the year 2000 are estimated as 14.8 billion gallons, an increase over 1962 water demand of 78-percent.

Jan 1, 1966

By M. Copeland

Phase relations of gadolinium alloyed, up to 40 weight-percent (wt pct), with AISI 304-type stainless steel were established. Body-and face-centered cubic iron-rich solid solution phases and several intermetallic gadolinium-containing compounds of variable composition that approximated the formulas Fe9Gd, Ni7Gd2, Ni3Gd, Fe2Gd, NiGd, and NiGd3 were identified. The intermetallic phases Fe9Gd and Ni7Gd2 were noted to melt at about 1,080° C at about 0 to 2 wt pct gadolinium. The melting temperature of Fe9Gd increased with increas-ing gadolinium content to a plateau at about 1,230°C and 30 wt pct gadolinium, and the melting point of Ni7Gd2 decreased to a plateau at 900° C and 30 wt pct gadolinium where Ni3Gd, NiGd, and Fe2Gd coexist. Body-centered cubic iron solid solution was stable from 1 to 2 wt pct gadolinium to higher contents, 30 wt pct gadolinium or possibly more, and face-centered cubic iron up to 12 wt pct gadolinium below 1,200° C. The stability of these phases above 1,200° C was not resolved except for the mel points. A limited number of fabrication variables as well as mechanical and corrosion properties of alloys containing up to 5 wt pct gadolinium were studied. Equilibrating and forming operations were best conducted at about 940° to 1,080° C. Some variability in the yield and tensile strengths of alloys was noted; however, there was a continual decrease in ductility and impact resistance with increasing gadolinium contents. The resistance of gadolinium alloys to corrosion in water at 354° C was about the same as stainless steel.

Jan 1, 1965

By J. A. Pile, Virgil Miller, R. G. Peterson, F. B. Petermann

"INTRODUCTION As virtually no published data are available on the sintering of fine, minus-100-mesh, ferrograde manganese ores, it is most opportune to present data on the amenability of various fine ores and mill products to the sintering process. These data cover the sintering or nodulizing of finely crushed, high-grade pyrolusite and rhodochrosite ores, sintering of manganese carbonate flotation concentrate, sintering or nodulizing the calcine from the deleading of a manganese oxide flotation concentrate, and sintering the calcines made in a Herreshoff furnace from the treatment of manganese sulfate products.If finely sized products are to be smelted in the present electric or blast ferromanganese furnaces, they must be sintered or nodulized. The only specification as to the size of the sintered or nodulized product is that it must pass a 6-inch screen and not contain over 1t-1/2 percent minus 20-mesh material. The minimum-maximum size has not been established. Undoubtedly this opti mum size will be set by the ferromanganese industry when ample quantities of manganese oxide sinters have been smelted."

Mar 1, 1942

By D. L. Sawyer

The Bureau of Mines studied alumina extraction from uncalcined, kao-linitic clay at temperatures from 1000 to 2500 C using 20-or 27-wt-pct-HCI concentrations and with an acid-to-clay ratio of from 0.8 to 1.4 times stoichiometric. Autogenous digestion pressures ranged from atmospheric pressure to about 900 psia. Extraction of 96 pct of the alumina was obtained by HCI leaching at temperatures and leaching times that varied from 1000 C for 120 h to 2000 C for 15 min. Hydrochloric acid stoichiometry of the reaction A1203'2Si02'2H20 + 6HCI + 2AICl3 + 2Si02 + 5H20 was studied at different temperatures and leaching times in a 750-mL tetrafluoroethylene-polymer-lined autoclave. A combination of high temperature and 20 wt pct excess HCI promoted rapid and almost quantitative extraction of alumina (99 pct in some tests). Additional Bureau data obtained with 35-mL tantalum bombs and leach-ing tests with added fluoride are also provided. At high temperatures, the addition of fluoride did not result in a significant improvement over HCI alone and was deleterious to the filtering properties of the digest residue.

Jan 1, 1985

Two different techniques were used to make measurements of the absolute value of electromagnetic noise in an operating coal mine, Robena No.4, located near Waynesburg, Pennsylvania. One technique measures noise over the entire electromagnetic spectrum of interest for brief time periods. With present instrumentation, the spectrum can be covered from 40 Hz to 400 kHz. It is recorded using broad-band analog magnetic tape, and the noise data are later transformed to give spectral plots. The other technique records noise envelopes at several discrete frequencies for a sufficient amount of tine to provide amplitude probability distributions. The specific measured results are given in a number of spectral plots and amplitude probability distribution plots. The general results are that at frequencies below 10 kHz, power line noise within the mine is severe. Impulsive noise is severe near arcing trolleys, and at lower frequencies near any transmission line. Carrier trolley phone signals and harmonics are strong throughout the mine whenever the trolley phone is in operation. Additional information beyond that included in this report may be obtained from the authors, who are with the Electromagnetics Division of the National Bureau of Standards.

Jan 1, 1974

By Robert L. Davidoff

Growing domestic and global demands for mineral resources have established an imperative need for developing comprehensive, versatile mineral supply analysis evaluation tools. The Minerals Availability System (MAS) of the Bureau of Mines is meeting this need with its computerized Supply Analysis Model (SAM). This paper describes the SAM system and the quantitative methods used by the MAS for mineral supply analyses. The MAS evaluating process consists of deposit identification, tonnage and grade determinations, engineering and cost evaluations, financial analyses, and supply curve generation. MAS has developed this computerized system primarily to facilitate the maintenance of data information for the constructing of commodity supply curves. The SAM system presently has the analytical capabilities of simultaneously (I) evaluating many mineral deposits, (2) updating mineral supply information to reflect inflationary changes in costs and prices, and (3) conducting sensitivity analysis to determine impacts on mineral supply under various conditions. Many potential users in both government and industry will find the SAM system a valuable tool for policy analysis, forecasting, and planning. The SAM system has been constructed so that any types of information that are similar to the data elements in the MAS data base may be used to perform supply studies. The storage space needed for the SAM system?s programs, files, and output data is approximately 14 million characters.

Jan 1, 1980

By Elaine T. Cullen

Underground mining, like many high-risk industries, is facing a crisis in the near future. This industry has traditionally relied on a master-apprentice relationship to train new workers, but experienced miners are retiring in large numbers, leaving few "masters" to properly train their replacements. With a recent resurgence in mining, many new miners are entering the workforce each day. The rise in the number of inexperienced workers has implications for worker safety in an industry in which one mistake can blow up the entire workplace. The explosion in the Darby Mine in May 2006 that killed five miners illustrates what can happen in hazardous environments such as underground mines. The Health Communications Team at the National Institute for Occupational Safety and Health Spokane Research Laboratory was asked to address this problem by developing new training and safety awareness materials to promote safe flame cutting and welding practices. This article describes how occupational ethnographic techniques provided insights needed for "new product development." The result of this work was a national initiative to raise awareness and to protect underground coal miners from the dangers of flame cutting and welding in an environment filled with solid fuel and methane (natural gas). Although this project was initially designed for the mining industry, the approach and lessons learned are applicable to any high-risk industry and should be of interest to other social marketing or occupational safety and health professionals.

Jan 1, 2009

By W. O. Vanderburg

This paper describing the methods of concentrating tungsten pros at the mills of the Atolia Mining Co. is one of a series of similar papers being prepared by the United States Bureau of Mines. The writer acknowledges the assistance and cooperation of A. V. Udell, president, Louis Warnken, bookkeeper, and C. K. Dennis, superintendent, of the Atolia Mining Co. in the preparation of this paper.

Jan 1, 1931

By Jack L. Henry

The monocarbide region of the ternary system U-C-O has been investigated at 1,700° C as the first phase of a more extensive study of a portion of the four-component system U-C-O-N. An area bounded by the following compositional limits in atomic percent was studied: U, 44 to 55; C, 30 to 60; 0, 0.2 to 20. Compacts composed of mixtures of uranium, graphite, and uranium dioxide powders were sintered at 1,700° C under an equilibrium pressure of carbon monoxide to produce uranium oxycarbide specimens having a variety of compositions. Sintered specimens were evaluated by X-ray, chemical analysis, and ceramographic techniques. Solid-solution boundaries and phase relations have been established, and the effects of composition on the lattice parameter as well as the decomposition pressure have been investigated. Oxygen can be substituted for carbon in stoichiometric uranium monocarbide to the extent of about 17 atomic percent at 1,700° C. The composition range of the oxycarbide solid solution extends from about 48 to 51 atomic percent uranium in the low oxygen region. Above 10 atomic percent oxygen the composition range narrows to less than 1 atomic percent uranium. Carbon monoxide exists as a gaseous phase in equilibrium with all compositions which contain oxygen. Five separate phase fields were found bounding the solid-solution area. Other phases within this portion of the system include uranium, uranium dioxide, uranium dicarbide, and uranium sesquicarbide. Decomposition pressures of oxycarbide compositions at 1,700° C have been found to vary from a few microns for stoichiometric and uranium-rich compositions to 35 torr for carbon-oxygen-rich specimens. Lattice parameters were found to depend upon the U to C + 0 ratio as well upon the extent of substitution of oxygen into the stoichiometric monocarbide lattice.

Jan 1, 1967

On September 4, 2007, Mine Safety and Health Administration, in alliance with the International Union of Operating Engineers and the International Association of Bridge, Structural, Ornamental, and Reinforcing Iron Workers, presented the first annual Mine Construction Maintenance and Repair?s Safety Contractor of the Year Award to Artisan Contracting, Inc., of Cape Girardeau, MO. Eligible contractors located throughout the United States were nominated. Artisan Contracting was nominated by Illinois Cement Company located in LaSalle, IL. Illinois Cement Company is a Division of Eagle Materials Inc., located in Dallas, Texas. Mr. Larry Frankum President of Artisan Contracting Inc., stated, ?While it is gratifying to receive a wonderful award such as this, we must not forget how fragile a good safety record is. We must constantly remain diligent in pursuit of maintaining safe work sites.?

Feb 1, 2008

By Thomas Jenning, C. M. Keithly

"INTRODUCTION This report is one of a series. 4. 5. 6/ concerned with presenting historical development, and operating data on secondary-recovery projects in various States to stimulate interest in sound secondary-recovery programs. Preceding reports in this series have dealt exclusively with descriptions of and results obtained by water flooding in three states, but no recent publication of comparable purpose describes gas-injection 7/ practices. The authors intend to present material relevant to the development and operation of gas-injection projects in Illinois, with particular emphasis on those producing from oil-bearing horizons that had been depleted to a point near the economic limit of operation by past oil-recovery methods.Most operators realize that the energy expended on the movement of fluids through gas-expansion- or gas-cap-type oil reservoirs to producing wells must be supplemented to attain maximum recovery of the oil present. Under favorable conditions, many operators choose to maintain oil-propulsive forces at or near their original magnitude by injecting extraneous fluids into a reservoir or recycling produced fluids early in the life of a field. More common, and less desirable, is the practice of replenishing these forces after primary producing methods become unprofitable. The lattes practice has been adopted in many stripper fields in Illinois and most of the oil-producing States during the last 40 years, but other old oil fields, and oil properties within those fields which were partly exploited by secondary--recovery methods, also may offer favorable opportunity for further development. To encourage and, aid operators in the development of gas-injection projects in the old oil fields of the United States, four projects have been described in detail in this report."

Nov 1, 1944

By Edward D. Thimons

This Bureau of Mines report presents expected levels of air pollutants in the face areas of oil shale mines, based upon data collected by the authors and previous investigators. Ventilation requirements to maintain these pollutant levels below their threshold limit values and Federal and local mine air quality standards are discussed. Two practical face ventilation systems are discussed in terms of actual in-mine test experience.

Jan 1, 1986