Search Documents

By R. L. Grant

The Bureau of Mines applied automatic computational methods to analyze the degree of correlation between sound transmission and atmospheric conditions. Statistical analysis of data collected over a 5-month period indicated that the following weather variables, listed in order of decreasing importance) have a significant effect on the transmission of sound in the atmosphere: 1. Wind velocity and wind direction. Winds in the direction of travel of the sound wave increase the sound intensity and duration. 2. Barometric pressure. High pressures are related to low sound intensities and durations. 3. Atmospheric temperature. High temperatures are related to low sound intensities and durations. Inversion of the atmospheric temperature did not appear to affect sound transmission under the conditions of this study.

Jan 1, 1967

By A. S. Peck

This report presents the results of a cooperative study between the Bureau of Mines and the University of Utah to define the mechanism involved in the adsorption of oleic acid and sodium oleate on fluorite, calcite, and barite, using an infrared spectrophotometer for identifying and measuring the adsorbed reagents and reaction products. Fluorite, calcite, and barite react with oleic acid and sodium oleate in a water system, forming chemisorbed and solution products. The chemisorbed species is a surface mineral cation-collector anion salt, Chemical analysis of solution resulting from the adsorption reaction indicates that the adsorption process causes displacement of mineral anions, namely, fluoride, carbon ate, and sulfate from the surface of these minerals.

Jan 1, 1963

By F. W. Hoertel

Tungsten from the hydrogen reduction of WF was vapor - deposited to coat MERM (Material Evaluation Rocket Motor ) graphite and rhenium- lined graphite nozzles . These nozzles have surface configurations that preclude the conventional fabrication of high- density- tungsten liners . Operation at 550 ° C produced selectively placed uniform coatings of specified thicknesses at near theoretical density . An acceptable coating could not be deposited on a beryllia nozzle because of an undesirable side reaction between the substrate and one or more of the products of the reduction reaction .

Jan 1, 1964

By Thomas M. Barczak

The Bureau of Mines is conducting research to optimize the capability of mine roof supports so that the selection and design of these supportsare compatible with the conditions in which they are to be employed. This report describes a study that investigates three parameters influencing the load-carrying capability of wood crib supports: height, configuration, and horizontal displacement. Four crib heights, four parallelogram configurations, and three ratlos of horizontal-to-vertical displacements were tested on full-scale wood crib supports in a mine roof simulator. Test results indicated a reduction in load-carrying capability for increases in crib height. Increasing the contact area by changing the intersecting angle between crib blocks to form parallelogram configurations provided a slight increase in load-carrying capability for the first 10 to 12 in of vertical convergence, after which the cribs became more unstable, resulting in significantly less load-carrying capability. Horizontal displacements did not appreciably affect the load-carrying capability of wood crib supports for the range of vertical displacements (less than 10 in) likely to be encountered underground. This report documents these tests and postulates some explanations of failure mechanics for the observed behavior.

Jan 1, 1988

By R. P. Adams, R. A. Beall

The Bureau of Mines developed a method to melt and cast specimens of hafnium- carbon alloy and studied their properties . A rotating - ladle vacuum or inert atmosphere arc furnace was designed , special electrodes and molds were developed , and operating procedures were worked out for casting small shapes . The cast specimens were evaluated according to their carbon content for melting point , density , microhardness , electrical resistivity , and oxidation resistance . Lattice dimensions were determined , and metallographic specimens were prepared . Photomicrographs were taken of specimens containing 2.72 , 5.50 , 6.47 , 9.97 , 12.8 , and 15.7 weight - percent carbon , and their grain structures were compared .

Jan 1, 1963

By D. Harrington

Springing or chambering of deep drill holes is common practice in some quarries. It involves definite hazards from premature explosion during placing of the springing charges or the final charge due chiefly to heating of the bottom of the holes by the successive exploding of the springing charges or, in some instances, from burning of paper or other material following detonation of the explosives The danger is either unknown or disregarded in many instances by those who place the charges in the holes. Disregard of this hazard probably is, at least in part, responsible for the far too high fatality and injury rate due to charging explosives and premature slots in quarry work. Awareness of the danger' should result in elimination or at least of material decrease in injuries from this cause.

Jan 1, 1941

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 Aner W. Erickson

"Preliminary examination of tungsten deposits on the Mountain View property near Hyder, Alaska, was made by Neal M. Muir, an engineer of the Bureau of Mines daring the summer of 1942. Fifteen samples were cut, rough esti¬mates of ore reserves were made, and it was proposed to extend the drift on scheelite-bearing vein 300 feet in a northwesterly direction.From May 22 to October 24, 1944, an exploratory project was conducted on the property by the Bureau. In the course of this work, the camp buildings were rehabilitated; the dam, hydraulic line, and machinery were repaired; 226 feet of drift was driven; 80 groove samples aggregating 3.9 tons in weight were cut; a 6,000-foot surface and underground traverse was run; and the area was mapped in detail.In its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to the national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples and performs beneficiation tests. Both these branches are under the supervision of Dr. R. S. Dean, assistant director.Special acknowledgment is doe Neal W. Muir, project engineer, and Robert S. Sanford, acting chief, Alaska Division, Mining Branch, for their supervision of the field work and revision of the report.Acknowledgment is also made to Silbak Premier, Ltd., for rendering valuable assistance in the repair of equipment and for extending various courtesies to Bureau of Mines personnel during the conduct of this project.The Mountain View property is located at latitude 55° 59' north, and longitude 130° 03' west in the Salmon River mining district of southeastern Alaska, about 5 miles in a northwesterly direction from the town of Hyder, which lies at the head of Portland Canal, as shown in figures 1 and 2. Vein outcrops and surface workings are at an elevation of 950 feet and occupy the west flank of a low ridge between Skookum and Fish Creeks, as shown in figure 3. The portal of the long adit exposing the vein at depth is on Skookum Creek about 550 feet north of the confluence of Skookum and Fish Creeks.Access to the property is over a 4-foot wide trail built and maintained by the United States Forest Service. This trail is suitable for pack animals and is adequate for transportation of supplies and material for exploratory work. During the periods of camp construction and past exploratory operations a 4,000-foot, single-cable, aerial tramway, now in disrepair, served for transportation of materials and all machinery from the Salmon River Highway to the property. The cost of such hauling was high, amounting to $12 a ton. Topography is suitable for construction of a ""cat road"" 2 miles in length, connecting the property with the Salmon River Highway. It is estimated that such a road could be built for $5,000 a mile, and supplies, machinery, and concentrates could be haled over it at a cost of less than $2.50 a ton."

Sep 1, 1946

By W. E. Anable

The Bureau of Mines studied the purification of commercially available yttrium by melting it in a 100-kw electron-beam furnace. Button-scale melts were made to determine the ultimate purification that could be attained by melting yttrium at 1,733° to 1,770° C at low pressure (0.05 to 0.1 micron) for 1 to 120 minutes. In addition, numerous melts were made to study the effect of doping yttrium with carbon, 17 selected metallic additions, and 3 compounds. Except for nickel and zirconium, the metallic impurities in yttrium were lowered significantly on extended treatment; silicon was lowered only slightly. The nonmetallic impurities} oxygen, nitrogen, and carbon, were not lowered except on short exposures. In isolated instances, the oxygen content was lowered from 5,860 ppm to about 5,000 ppm. In most instances the carbon con-tent was lowered from 545 to about 220 ppm in 20 minutes and then increased again. It was concluded that yttrium cannot be purified by direct heating or by the doping technique employed.

Jan 1, 1965

By Francis X. Cannaday

The Bureau of Mines developed equipment to measure the sonic velocity of pulses transmitted through rock samples varying in size from laboratory specimens to mine pillars in place. Pulses are produced by electronically excited piezoelectric ceramic transducers. Special equipment components were developed by Bureau facilities; other components are commercially available. The technique permits a nondestructive, repetitive, stable, shaped pulse to be used in place of explosive caps or hammer blows. Longitudinal wave travel time measurements were taken on an oscilloscope screen; transverse wave measurements were taken under special field conditions. Results were consistently repeatable within the accuracy of the oscilloscopes utilized.

Jan 1, 1966

By Charles L. Ross

A successful placer mine is being operated by the E. T. Fisher Co. on Rock Creek in the South Pass mining district at Atlantic City, Wyo. About 2,800 cubic yards of gravel is dug daily by a gasoline-driven dragline shovel with a 1 1/4-yard bucket and washed in a movable plant with a gold-dredge trommel and standard-dredge sluice boxes; the total cost is about 12 cents per cubic yard. The gold-bearing gravel occupies a narrow valley between two low ranges, of hills. The ground is covered by brush and willows, which are cleared of in the fall by burning after the leaves have dried. The elevation at the mine is 7,600 feet above sea level.

Jan 1, 1935

By R. E. Siemens

A process is being developed by the Bureau of Mines to selectively recover nickel and cobalt from low-grade domestic laterites. In laboratory evaluation of the process, the oxides in the laterite were selectively reduced with carbon monoxide at temperatures from 350° to 600° C. For material containing more than about 5 percent magnesia, pyrite additions or post-reduction heat treatments were necessary to achieve satisfactory nickel and cobalt extraction for this range of reduction temperatures. Multistage leaching of the reduced material at ambient temperature and pressure in the presence of oxygen, ammonium sulfate, and ammonium hydroxide extracted up to about 90 and 85 percent of the contained nickel and cobalt, respectively. The nickel was selectively recovered from the leach solution by solvent extraction and was then stripped from the loaded organic with dilute sulfuric acid to provide a nickel-rich electrolyte. Treatment of the raffinate with hydrogen sulfide resulted in the recovery of cobalt as a sulfide. The only contaminant in solution was magnesium which was removed by ion exchange or precipitation. In this process the energy requirements are relatively low and except for minor operation losses, only coke and oxygen are consumed.

Jan 1, 1975

By A. J. Keast

This circular is one of a series dealing with the exploration, equipping, and development of mining properties, prepared and published by the United States Bureau of Mines in cooperation with various mining and exploration companies in the United States and Canada. This series of papers will supplement an earlier one which covered the methods and costs of mining and milling at a large number of producing mines. The present paper describes the exploration, equipping, and developing of a group of 18 claims remote from rail transportation, and the transport of equipment and heavy supplies for a distance of 120 miles by tractor over ice and winter roads, and of men and lighter supplies by airplane.

Jan 1, 1933

By Russell R. Trengove

Core samples from an ore horizon 2,000 feet below the surface were successfully obtained by rotary drilling at the property of the Eureka Corp., Eureka, Nev. The ore was soft and friable; cores were not obtained previously with diamond drills. Whipstocking was used to get samples in a zone 200 feet from a vertical hole. A technique in shipstocking, by which the direction and deviation of the holes were controlled by means of nonfriction-type survey instruments, was successfully employed.

Jan 1, 1956

By O. Terichow

A pendulum sclerometer designed by the Bureau of Mines is described. Its method of operation is given, along with the results of tests made on representative mineral samples of Mohs' hardness scale to determine the applicability of the device for research on rock testing. The sclerometer hardness values obtained from the tests indicated that reproducibility and accuracy were good. A quantitative comparison of the pendulum hardness values with microhardness and surface energy values published by other investigators showed good agreement on minerals with Mohs' hardness numbers of 2 to 9.

Jan 1, 1967

By T. T. Read, T. L. Joseph, F. H. Royster

In a preliminary study of the beneficiation of iron ores conducted by the Bureau of Mines, one of the authors (T. T. Read) found it necessary to ascertain, if possible, how much effect a decrease in the silica content of an iron ore has upon the cost of making pig iron from the ore. In the beneficiation of iron ores the most important impurity to be removed is usually silica, and the amount that can be expended on a beneficiation process to reduce the silica content of the ore is obviously determined by the amount of increase in the value of the ore after beneficiation. The price that can actually be obtained for a beneficiated ore is, of course, a matter of negotiation between the seller and the buyer, but since the relative value of different grades of iron ore must be chiefly based upon the cost of making pig iron from them, an approximation as to the effect which decrease in the silica content of ore has upon the cost of snaking pig iron is an important guide in estimating what probable average gain will result from subjecting an ore to a beneficiation process. A search of the literature failed to reveal any detailed statement on this important topic, but fortunately the data are at hand to permit making an approximate calculation of the probable effect. For the purpose of the calculation assume three iron ores with the following composition (natural):

Jan 1, 1924

By L. G. Austin

"This paper is based on the development of the Maza-Austin technique for characterizing thousands of coal particles by approximate analysis of the major inorganic constituents Ca, Al, Si, K, Na, Fe and S in each particle. The technique has sufficient sensitivity to work on small volumes, is fast enough to handle large number of particles within a reasonable period of time, and consists of scanning electron microscopy combined with energy dispersive x-ray spectrometry (SEK-EDS). A computerized SEK-EDS system that allows the automated analysis of hundreds of coal particles per hour' is described. The analysis is based on the location and tracing of coal particles embedded in a polished specimen, the selection of sampling points on the traced particles, the collection of an x-ray spectrum from each sampled point for a defined period of time, and the processing of the x-ray intensity to calculate point composition using ZAF corrections. Procedures for correcting for dead time, background, detector efficiency and spectrum overlap are described. These corrections are essential if reasonably accurate analyses are to be obtained from unknown complex mixtures of the elements in a coal or fly ash particle. Examples are given. INTRODUCTION Coal is a complex mixture of organic and inorganic materials. The inorganic fraction is referred to as mineral matter (Gluskoter, 1978) but can occur in three modes: (i) an observable mineral species; (ii) as cations held by ion exchange to carboxylic groups; and (iii) in chelate complexes. The mineral matter content normally represents a significant proportion of a coal, with an average value of about 15% for US coals (Gluskoter, 1975). The standard methods of analysis of the mineral matter in coals are performed on a sample selected to represent the whole coal as closely as possible, and give the overall inorganic composition in the coal. Such analyses are of limited use for solving problems originating from the behavior of individual coal particles, whose compositions vary widely from the average value. This is particularly true in pulverized coal combustion, where the current methods of predicting the slagging and ·fouling potential of a coal are based on the bulk ash composition, but the fly ash particles which create the deposits originate from coal particles with large differences in mineral compo1ition. Some examples can be found where, in a comparison between two coals, the one with the smaller slagging potential according to the mean ash composition was the one that behaved worst in the furnace (Moza et al., 1980; Koza and Austin, 1983). The u1e of gravity fractionation to assess the slagging potential of pulverized coals has shown that conventional ASTM analysis is not sensitive to differences in the distribution of mineral matter when comparing coals (Borio and Narciso, 1979). Bryer (1979) concluded that coals should be examined for fouling and slagging potential by analyzing gravimetric and size-fractionated coal, preferably pulverized· and ground to the size expected at the mill outlet."

Jan 1, 1989

By L. J. Kane

Several processes being developed by the Federal Bureau of Mines to provide new and more efficient uses for coal require practical methods for removing dust from hot gases. Filters provide such means. The efficiency of filters made of aluminum silicate fibers and porous stainless steel was determined. The results obtained with the fibers were previously reported.5 In this investigation tests were made with three porosities of stainless steel filter material (grades C, D, and E) at a gas flow of 1,000 std. c.f.h./sq. ft. of filter, temperatures of 75° and 1,000° F., and dust loadings (as represented by cumulative dust fed) of 100, 1,000, and 10,000 gr./sq. ft. of filter. Pressure drop during the runs ranged from 0.1 to 21 in. of mercury, and dust removal from 25 to 99.93 pct. Filters having the finest pores gave the greatest pressure drop and percentage of dust removal; however, their dust-holding capacity was slightly lower. Usually, their ability to remove a higher percentage of dust at the same pressure drop more than compensated for the slightly lower dust-holding capacity. With increase in temperature, for the same weight rate of flow of gas, the pressure drop increased and the percentage of dust removal decreased. The effect of temperature was probably due to the accompanying change in the linear velocity and viscosity of the gas.

Jan 1, 1961

The performance of two large-capacity ventilation systems was compared through tests conducted in a large dead-end heading at a pilot oil shale mine in Colorado. Sulfur hexafluoride (SF6) tracer gas was used to measure the performance of the two systems: a free-standing jet fan and a reversible fan with rigid duct. The tracer gas was used to simulate the production of mine air pollut-ants, including blasting pollutants, hot diesel emissions, free methane from surrounding strata, and methane desorbing from muck piles. The test room was 55 ft wide, 30 ft high, and 320 ft long. The performance of the two fans was similar, but the jet fan used less power. The tests showed that either system could provide effective ventilation during oil shale mining.

Jan 1, 1986

By Ludwig Schmidt

The consumption of gasoline in the United States varies materially with the seasons; during some of the summer months it exceeds the rate of production and in the other seasons the production of gasoline exceeds the consumption, The usual practice of the larger refiners is to store surplus stocks during the winter season in order to meet the heavy demands during the summer months. The following table shows the stocks of gasoline at refineries on the last day of April for the past five years: 1919 593,616,170 gallons 1920 643,5526644 " 1921 747,222,900 " 1922 892,567,766 " 1923 1,336,417.871 "

Jan 1, 1923