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By F. G. Horino

This report presents the theory and design of a stiff loading machine used by the Bureau of Mines. The machine incorporates three high-strength steel columns as the restraining member in parallel with the specimen. The theory presented gives the basis of design and the dimensions of component parts of the machine. Laboratory verification of the theoretical stiffness is described using three different setups involving a hydraulic jack and spacers and confirms the stiffness calculations to within 1 percent. Experimental techniques, testing procedures, and special equipment designed for determining the complete stress-strain behavior of NX cores of both hard and soft rock are described. Typical test data are presented as force-displacement curves for two rock types, a marble and a granite.

Jan 1, 1972

By E. M. Murphy

Comparative data from ASTM method of test E-162 and large-scale trials in the Experimental Mine show that the flame-spread quality of brattice cloth and other ventilation control materials can effectively be evaluated by either method. Materials having a flame spread index of 25 or less, as determined by the simpler and more economical laboratory test ASTM E-162, do not present a serious fire hazard when used in coal mines.

Jan 1, 1972

By E. G. Davis

The flash reduction of fine iron ore in a dilute-phase system was investigated at 500° to 900° C within a heated stainless steel tubular coil. Alabama brown iron ore and Mesabi semitaconite ore were fed into the coil concurrently with reducing gases of hydrogen and reformed natural gas, so that the velocity of the gas at the reaction temperature was sufficient to entrain and pneumatically transport the solids through the coil. Reduction is very rapid with retention time of the ore in the coil varying from 4 to 15 seconds. Variables affecting reduction are temperature, ore feed rate, and gas flow or velocity. Results of the studies show that a partially reduced product (10-to 25-percent reduction) can be made which, on subsequent magnetic concentration, yields a concentrate containing 64 to 70 percent iron with a 90-to 94-percent iron recovery. Maximum reduction of 77 percent was obtained when hydrogen was used in a four-stage reduction test to yield a product containing 61 percent metallic iron.

Jan 1, 1972

By William J. Campbell

Three types of X-ray analytical instrumentation were compared for applications in the secondary brass and bronze industry. The instruments were a conventional X-ray spectrograph, a portable X-ray spectrograph, and a radioiso-topic X-ray analyzer using balanced filters. The following two general applications were considered: Rapid identification for sorting scrap metals and quantitative analyses to provide guidance in the melting and casting of alloys. Twenty-three analyzed copper-base alloys were used as standards. Although the alloys varied widely in composition, matrix correction procedures were not necessary except for copper. The conventional X-ray spectrograph provides positive identification of the alloys and quantitative values for the six elements investigated--aluminum, copper, iron, lead, tin, and zinc. Equivalent results were obtained with the portable X-ray spectrograph for those elements whose characteristic X-rays are in the wavelength range of the instrument. The radioisotopic X-ray analyzer distinguishes certain groups of alloys and provides quantitative determinations for copper, lead, tin, and zinc. The sensitivity of the analyzer was marginal for the determination of small concentrations of elements of atomic number 26 or lower.

Jan 1, 1972

By Ted C. Briggs

A special high-pressure Burnett-type compressibility apparatus was constructed and used to determine compressibility factors for pure helium, pure nitrogen, and nine helium-nitrogen mixtures containing 89.47, 79.04, 69.69, 60.09, 49.24, 41.02, 30.99, 20.53, and 10.67 mole-percent helium. A total of 161 runs were made consisting of 2,355 observed pressures. Data were obtained at 0°, 25°, and 50° C and at pressures to 1,000 atmospheres. A power series in the reciprocal volume, commonly called a Leiden series, is used to represent the compressibility factors. Three parameters in the series are required to represent helium, five parameters to represent nitrogen, and from three to five parameters to represent the mixtures. Compressibility factors are believed to be accurate to better than 0.1 percent over the entire pressure, temperature, and composition range.

Jan 1, 1972

By R. P. Vinson, Abdurrahman Cetinbas, Joseph Cervik, M. G. Zabetakis

The effect of water infusion on the flow of methane and on the production of dust was investigated at an active face in the Pittsburgh coalbed. The average total flow of methane at the face decreased by approximately 79 percent, whereas the flow from the ribs increased about 24 percent after infusion. On the day after infusion, dust concentrations appear to have been reduced; however, the presence of large quantities of rock dust obscured the results on the following days.

Jan 1, 1972

By Abdurrahman Cetinbas

The effect of water infusion on the flow of methane and on the production of dust was investigated at an active face in the Pittsburgh coalbed. The average total flow of methane at the face decreased by approximately 79 percent, whereas the flow from the ribs increased about 24 percent after infusion. On the day after infusion, dust concentrations appear to have been reduced; however, the presence of large quantities of rock dust obscured the results on the following days.

Jan 1, 1972

By L. A. Neumeier

The Bureau of Mines evaluated creep properties of Zn-Cu-Ti alloys that were annealed after finish-rolling either cold) or at 480° F (249° C). Compositions ranged up to 1.25 pct Cu and 0.36 pct Ti. Most data are for sheet annealed after finish-rolling to 92-pct total reduction. Annealing times were varied at temperatures between 320° and 560° F (160° and 293° C). For a number of the alloys, annealing after hot-rolling at 480° F affects creep properties very differently in longitudinal and transverse sheet directions. The detrimental result is that the anisotropy in creep properties between the two directions can be vastly increased. Conversely, specific annealing treatments of certain heavily cold-rolled alloys result in surprisingly low anisotropy in creep properties and the low anisotropy coincides with excellent creep resistance for both directions. Supplemental data are presented on tensile, hardness, and thermal expansion properties, and microstructures.

Jan 1, 1972

By M. G. Zabetakis, T. D. Moore

The use of a partially slotted 6.5-inch-inside-diameter vertical pipe to remove methane from a longwall gob area at a depth of 2,260 feet in the Pocahontas No. 3 coalbed ms investigated. The value of gas removed by such a pipe under free-flow conditions was found to equal the cost of the installation in this case. Approximately 25 percent of the available methane passed through the pipe without the use of an exhauster; an additional 10 percent was removed when an exhauster was employed. The diversion of methane through a vertical slotted pipe to the surface permitted the use of increased mining rates and decreased the ventilation air requirements.

Jan 1, 1972

By E. R. Cole

Laboratory heats of an 80 percent copper high-leaded tin-bronze alloy, similar to Brass and Bronze Ingot Institute (BBII) alloy 3A, were made with reduced tin content to determine whether an alloy comparable to BBII alloy 3A could be produced using less tin to aid in conserving this strategic metal. The tin content was lowered from 10 percent to 8 percent and 5 percent (nominal values), respectively, and the reduction in tin was offset by either increasing the lead content or adding zinc. Mechanical properties, machinability, and corrosion characteristics of the resultant alloys were investigated, and the mechanical properties were compared with BBII typical values and American Society for Testing Materials (ASTM) minimums for high-leaded tin-bronze alloy. Results indicate that the tin content of this alloy could be reduced approximately 1 percent (difference between the 8.4 percent actual tin composition obtained and the 9.3 percent BBII minimum) without seriously affecting the desired properties. Results also show the tin content could be reduced without significantly increasing the chances of rejects for mechanical property failures, which might result from normal variations in the casting process.

Jan 1, 1972

By M. A. Mahtab

This report presents a new procedure for analyzing the orientations of rock fractures in an engineering site. This procedure, coded in a computer program, identifies clusters or groupings among the fracture orientations and calculates (1) the mean orientation of the fractures within each cluster and (2) the dispersion or scatter among these fracture orientations. Data points are represented by intersections of joint normals with the upper hemisphere, which is divided into 100 equal-area quadrilateral patches. The points in adjacent patches where the Poisson distribution test shows significant concentrations are assigned to a single cluster. For a cluster whose fracture orientations follow Arnold's hemispherical normal distribution, a confidence interval for the fracture orientation mean is calculated by applying Fisher's estimates. The technique is applied to the treatment of three examples.

Jan 1, 1972

By J. R. Allsup

Air pollutants in exhaust gas produced from LP-gas (propane) were studied using both laboratory engines and vehicles. The objective of the study was to evaluate engine parameters relating to the advantageous use of propane as a low-pollution fuel. Some comparisons are made between gasoline, natural gas, and propane. Results show that engines can operate over a wider range of A/F with minimum carbon monoxide and hydrocarbon emission when using propane than when using gasoline. Mixture enrichment using propane is unnecessary during cold starts, thereby eliminating the emission penalty during warmup. Carbon monoxide and hydrocarbon emission using propane are unaffected by ambient temperature. The photochemical reactivity of hydrocarbon emission is considerably lower with propane than with gasoline.

Jan 1, 1972

By Mark I. Copeland

A study was conducted to determine if commonly used alloying additions or coating materials can prevent the formation of a liquid-copper phase during the reheating of copper-containing steels. If so, the tendency of such steels to surface-crack during hot-working might be eliminated. Steel specimens were scaled by heating them either isothermally or in a programed manner that simulated industrial furnace practice. Metallographic examination of the heated specimens showed that molten fayalite (Fe2Si04) completely prevented the formation of liquid copper at the surface. Fayalite, which melts at 2,200° F (1,205° C), was formed by internal oxidation of the silicon contained in the steel. By forming complex molten oxides, coatings of borax glass were also effective in preventing the occurrence of liquid copper at the steel surface.

Jan 1, 1972

By R. L. Schmidt

One of a series published by the Bureau of Mines covering research investigations in rock drillability, this report of field drilling results extends earlier laboratory findings and provides a relatively simple procedure for predicting percussive drilling rates with reasonable accuracy. Two percussive drills mounted on a truck were used to drill a total of 25 rock types, and the results were used to develop a prediction equation. The equation was tested on a set of unrelated laboratory percussive drilling data, and the comparison between predicted and actual rates is shown in tabular form.

Jan 1, 1972

By Donald P. Blasko

The first well that produced commercial quantities of oil in the Cook Inlet Basin of Alaska was completed in 1957. Since that time oil production in the basin has increased rapidly and by the end of 1969 had reached an annual rate of 74 million barrels. Five major oilfields had been developed, and two additional discoveries awaited development. Estimated amounts of recoverable oil by primary and secondary recovery methods total 2.7 billion barrels, or 36 percent of the estimated oil originally in place. Repressurization by injecting gas or water in formations containing undersaturated oil has significantly increased the volume of recoverable oil. All production has been from formations of the Tertiary age; that much of it is from depths of 10,000 feet or more is unusual for Tertiary formations. The oils are low in sulfur and contain low to moderate amounts of asphalt.

Jan 1, 1972

By John Ward Smith

Detailed oil yield, lithologic, and mineral distribution data are presented for core and drill-cutting samples from the Western Oil Shale Corp. Project Utah EX-1 Corehole (WOSCO EX-I), drilled to sample a deeply buried oil-shale sequence in the Green River Formation of Utah's Uinta Basin. Drilling of this corehole was part of the evaluation of this site for possible oil-shale development by nuclear explosion. Sections sufficiently thick for nuclear development average 15 gallons per ton or less and consist predominantly of low-grade shales. Some properties of low-grade shales may be advantageous to a nuclear experiment by facilitating breakage, fracture development, and in situ retorting. The formation correlates precisely with the well-studied oil shales 25 miles east near the Colorado border. A 235-foot mineralized section containing nahcolite, shortite, and searlesite whose bottom lies 300 feet above the Mahogany zone is described.

Jan 1, 1972

By Larry A. Haas

Carbonyl sulfide (COS) was decomposed to sulfur and CO in a silent electrical discharge. A threshold of about 4 kv at 60 Hz was required to dissociate the gas in a laboratory ozonizer at 790 torr with electrode gaps between 1 and 5.5 mm. Above the threshold value, the reaction rate increased with increasing voltage with helium or nitrogen diluent. With the latter diluent, higher voltages had to be applied to obtain the same yield in the 4-to 12-kv range. The COS decomposition rate increased with COS concentration, but a saturation value was reached at about 10 pct COS. The reaction rate decreased at low linear gas velocities as obtained at lower gas flows, larger electrode gaps, or larger reactor volumes. Increasing gas temperature also decreased the decomposition rate. The presence of solid adsorbents such as quartz wool, bauxite, or charcoal had no significant effect on the reaction rate. The addition of S02 did not affect the COS decomposition rate, but small amounts of water decreased the reaction rate. Over 50 pct of the COS was decomposed at room temperature and atmospheric pressure in a l7-kv ozonizer using a gas containing 0.9 pct COS in helium flowing at a rate of 0.3 liter/min. The average current was less than 5 ma. This method has possible application in eliminating the toxic air pollutant, COS, which is generated in petroleum refineries and in processes involving reactions between sulfurous and carbonaceous materials. Carbon monoxide that is formed can be further oxidized to CO2 after the collection of elemental sulfur.

Jan 1, 1972

By George J. Conroy

Electrical power generation was studied in a laboratory-scale, open-cycle vortex MHD generator, which offers several advantages over straight-channel generators that require separate combustors. Compactness, lower capital cost, and high-energy release are obtained by combining the combustor and generator into one unit in the vortex generator. In addition, the vortex generator uses a simple solenoid rather than the more complex and expensive saddle magnet required for straight channel generators. Although the vortex generator must utilize combustion gases with a low Hall coefficient in order to be efficient in direct comparison to the linear generator, the primary motivation for this experimental device in terms of ultimate objective was to investigate the vortex generator with applications to direct coal firing and with combustion taking place in specially designed expansion nozzles. The vortex device offers one decided advantage over the linear device in this regard because slag deposits do not degrade or short-circuit the coaxial electrodes as is the case for a linear machine. The experimental vortex generator consists of a modified cyclone burner 7 ½ in ID by 21 in long, with the inner wall used as one electrode together with a coaxial center electrode. Power was obtained by impressing an axial field of 3,000 G from an air core solenoid magnet. Tests were conducted by seeding natural gas seeded with potassium acetate and burning with preheated oxygen-enriched air. Power generation was lower than calculated because theoretical plasma velocities were not achieved.

Jan 1, 1972

By Robert B. Worthington

This investigation was undertaken to develop a more efficient copper smelting practice that would help meet the increasingly stringent antipollution standards. Continuous smelting to copper and a 0.8-to 5-percent copper slag using pure oxygen has been demonstrated for several hours at a time in a unique double furnace, which was devised to overcome the heat losses inherent in a laboratory furnace. The use of pure oxygen to effect the smelting and conversion of copper sulfide concentrate in a single unit to produce blister copper and a very high S02 concentration provides a much reduced gas volume for more economical and thorough sulfur recovery. Although the process was successfully demonstrated for several hours at a time, extended test work using longer runs will be required to balance the system and to obtain test data for adequately demonstrating its technical feasibility.

Jan 1, 1973

By Robert C. Steckley

A study of joints in Marathon County, Wis., was made to determine the orientation of regional paleotectonic stresses and to develop a method of using optical diffraction analysis (ODA) in studying joint orientations and spacings. Standard geologic and petrofabric techniques employing the use of a geologic compass and a Schmidt net were used in gathering, describing, and reducing joint orientation data. Analysis of selected outcrops with ODA indicates that ODA can be applied to study both joint orientations and spacings. ODA is shown to be a rapid method that can be used to complement standard petrofabric techniques, especially in the study of joint spacings.

Jan 1, 1972