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By Jack E. Fraley

Magnesium oxysulfate cement has been specially formulated as a sealant in underground coal mines for reducing sloughing of shale roofs and coal ribs, for reducing air losses through block stoppings, for constructing sprayed stop-pings over approved jute cloth or metal lath, and for reducing combustibility of polyurethane foam. A standard spray machine (Mining Enforcement and Safety Administration (MESA) approved) was used for the underground testing. Our research shows that a 1/2-inch coating reduces shale and coal sloughing, reduces air losses through block stoppings, and prevents fire propagation through a metal tunnel lined with polyurethane foam. During the underground tests, excess mixing water was used to improve pumping the slurry to the spray nozzle. This was later found to increase shrinkage cracks in the cured coatings. Controlling excess water is important to an acceptable coating.

Jan 1, 1976

By F. W. Hoertel

The effects of certain process variables on the grain size, grain type, and microhardness of vapor-deposited tungsten were established, and the near-optimum parameters and the efficacy for the vapor deposition process were determined. No significant change in the grain size or microstructure resulted from ultrasonic vibration of the substrate during deposition, from variations in the hydrogen (H2) to tungsten hexafluoride (WF6) ratio, or from small increases in reaction-chamber pressure. Near-optimum conditions were continuous deposition at atmospheric pressure, a deposition rate of 2-mils thickness/square inch of substrate area/hour, a temperature of 5500 C, and a hydrogen to WF6 ratio of 4:1. The addition, individually, of about 2 volume-percent of butane, 24 volume-percent of carbon dioxide, or 4 volume-percent of propane to the hydrogen and WF6 mixture produced deposits with the finest grain size for each gas. A corresponding increase in microhardness accompanied the decrease in grain size. The addition of gases did not alter the columnar microstructure found in vapor-deposited tungsten.

Jan 1, 1966

By R. E. Collom

The spontaneous explosion of charges of nitroglycerin placed in deep wells situated in parts of the Ranger and Caddo fields of North Texas has aroused considerable inquiry among operators end others as to the probable agency, or combination of conditions, which causes the explosion.The method now followed, under certain physical conditions of a well, of setting a charge of nitroglycerin and allowing it to explode spontaneously was discovered locally by accident. In certain deep wells where formations, overlying productive strata, cave upon withdrawal of casing, it has been the practice to fire the shot electrically. In some of these operations the electric wires are broken or the firing system is otherwise deranged by pulling casing or the caving of hole prior to the time for firing. Sucn accidents make it necessary for the driller carefully to clean cavings out of the hole to a depth close to the top of the charge, after which in the normal practice, an attempt is made to fire the charge by dropping a ""jack-squib"", fitted with a fuse and detonator, down the well. Mr. R. L, Fowler, production manager for the Pierce Oil Corporation, reports that a delayed shot was thus successfully tired through four feet of caved material lying on top of the nitroglycerin shells.When a shot destined to be fired electrically fails, because of the above mentioned accidental conditions to the electric firing system, much time is required for the driller to run casing into the hole and clean out caved material. It was during the time of such uncompleted operations that the spontaneous explosions first noted took place. Having noted these spontaneous explosions the well shooters now intentionally place a charge in deep holes, which because of probable caves would otherwise have to be tired electrically, and wait for the charge to go off. No detonators are placed with the charge.

May 1, 1920

By Earl C. Lane

The Bureau of Mines is making a survey of petroleum products manufactured on the Pacific Coast from California crude oils . California crude petroleum is known to differ in some characteristics from the crude oil produced in other parts of the United States , and the claim has been made that the present Federal specifications are unduly severe when applied to the products made from California crudes . The main purpose of the present survey is to determine whether these claims are justified . This report deals only with California gasolines . Other products , such as burning oil , fuel and lubricating oils , will be taken up later . The samples reported were furnished in most cases , by the four large refining companies located on the Pacific Coast , although a number of samples of motor gasoline were purchased in the open market . In Los Angeles , samples of motor gasoline were obtained from service stations representing as many different refineries as possible . Inasmuch as San Francisco is one of the cities covered by the regular semi -annual motor gasoline survey conducted by the Bureau of Mines , it was not considered essential that the set of samples obtained from this city be as comprehensive as would otherwise have been necessary . The gasoline consumed in the States of Washington and Oregon is furnished for the most part by California refineries , and no effort was made to procure samples from these States .

Apr 1, 1922

By Robert J. Anderson

"Introductory Statement.In founding any kind of castings, even with the best practice, scrap castings are produced because of rejections for certain defects. Casting los¬ses are a serious source of financial loss in iron and steel foundry practice as well as, in brass and bronze, but they are particularly serious in aluminum foundry work because of the high value of aluminum. The indications are that in many aluminum foundries in the United States, the casting losses are at times high, and in some plants they are entirely too high when compared with average practice. Of course, defective castings have a residual value for remelting, but if much machine work has been done on a casting before it is scraped, the labor costs alone may exceed the value of the metal and even that of the rough casting.In a foundry, the monetary losses incurred through the production of waster castings can be ascertained from calculations based upon adequate scrap-loss reports. Such reports, when properly kept and interpreted are a valuable aid in finding foundry costs, but they are primarily useful in diagnosing the causes for casting losses. Many aluminum foundries in the United States do not keep adequate records of strap losses; as a result the causes for defective castings can not be traced, nor preventative measures adopted. However, some of the large aluminum foundries keep excellent records, and it has been found that these involve little extra expense for clerical work. If a foundry man will study his daily production of defective and waster castings, he will be able to trace the causes or losses and then make such corrections in his plant practice as will effect a considerable reduction in these losses -- as much as 50.0 per tent in some foundries. If all the present casting losses of the United States could be reduced 50.0 per cent, by eliminating only the readily preventable defectives, a saving of several million dollars would accrue. In the aluminum-foundry industry alone, the saving would amount to about $600,000."

Apr 1, 1920

By B. D. Sartwell

Multiple-charged beams originating from a 300-kv ion accelerator are important tools in the study of metal surfaces and thin films. A knowledge of the particle range is necessary for an understanding of the interaction processes of the ions with the targets. Utilizing a theory developed by Lindhard for determining the range of low-energy ions in solids, the ranges of H, He, C, N, 0, and Ar ions in A1203, Al, Fe203, Fe304, CuO, Cu20, Fe, Cu, Sn, and W were calculated for the energy range 60 to 400 kev using a computer program written in BASIC. The range, presented in graphical form, is given in both µg/cm2 and angstroms. In addition, heavy ion ranges were calculated for comparison with published experimental values. For ions with Z > 5, the discrepancy between the calculated values and published experimental values generally ranged from 2 to 40 percent; the largest deviations were probably due to experimental error.

Jan 1, 1970

By Je M. Oh

The Bureau of Mines is conducting research to determine the high temperature oxidation resistance of substitute stainless steels (SS) containing two less strategic elements, Al and Si, instead of Cr. Chromium is considered to be a critical and strategic metal. Although the Cr content was reduced to 8 wt pct, the alloys showed better oxidation resistance than did 304 SS containing 18 wt pct Cr. Specifically, the alloys that contained Fe-8Cr-16Ni with combinations of Al and Si showed excellent oxidation resistance even at temperatures up to 1,000° C. In this study, the effects of the alloying elements on oxidation kinetics and morphology of oxides were investigated using a Cahn Rg electrobalance, scanning electron microscopy, an energy-dispersive X-ray analyzer, X-ray diffraction, and an electron microprobe. Aluminum and silicon additions in combinatin were more effective in providing oxidation resistance than either element was alone.

Jan 1, 1986

By Frank D. Lamb

Pyrophyllite, a hydrous aluminum silicate (Al2 Si4O10 (OH)2 ) has been mined in North Carolina and marketed without beneficiation for the past 100 years, but recent demands for higher-grade material indicate that an economical concentration method is needed for at least a part of the pyrophyllite production. Past production has depended upon selective mining and hand sorting, which is often unsatisfactory because of the finely disseminated character of the ores. The major impurity in North Carolina pyrophyllite ores is quartz, which accounts for the abrasiveness of the commercial product. Since pyrophyllite is only slightly heavier than quartz, those ores cannot be beneficiated by simple gravity-concentration methods. Some separation can be attained by differential grinding and air classification because of the difference in hardness of the two minerals) but the separation is not sharp. Froth flotation of pyrophyllite from Quartz has never been attempted commercially, but if the demand for high-grade material is sufficient, it would seem that this process offers the most premise of being economically feasible.

Jan 1, 1950

By Jeffrey M. Listak

The Bureau of Mines has conducted a rock mechanics study to monitor deformation of near-seam strata above a longwall panel in the Pittsburgh Coalbed. The primary goal was to determine the height of caving immediately behind advancing longwall face supports. This study, although site specific, provides information on the caving mechanism associated with longwall extractions so that strata behavior and its interaction with longwall face supports can be better understood. Two holes were drilled, approximately 550 ft apart along the center line of a longwall panel, from the surface to the coalbed approximately 650 ft below. Various downhole geotechnical instruments were used to monitor strata deformation. In addition, surface elevation surveys were conducted to differentiate between surface and subsurface activity. This report discusses the caving characteristics of the strata as the longwall panel approached and passed beneath the boreholes. Physical property data are also presented to demonstrate the relationship between caving behavior and local geology. Data show that immediate caving of strata above the longwall face occurred at a height less than 23.5 ft and that strata behavior above longwall extractions is highly dependent upon lithology, with major disturbances occurring at weak lithologic zones.

Jan 1, 1986

By John P. Conway

This Bureau of Mines investigation was undertaken to determine the feasibility of lock-bolt support in Tertiary-gravel material. Pull tests were performed on five types of rock-bolt anchors to determine their optimum anchorage capacity. Four of these anchors are commercially available; the fifth, an explosive-anchor bolt, was developed by the Bureau of Mines. To increase anchorage capacity, epoxy grout was used with several of the commercial types of bolt. Tests showed that sufficient anchorage could be obtained by employing epoxy-resin grout with the commercially available wedge bolt, or by using the explosive-anchor bolt. Also estimated are bolt spacing and cost of a rock-bolt support system.

Jan 1, 1971

By M. G. Zabetakis

Amyl nitrite (C5H11NO2) is a pale-yellow liquid with an ethereal fruity odor and a pungent aromatic taste. Its use in first-aid treatment of cyanide poisoning has been suggested by Chen and his coworkers. Although not the most effective treatment, it is the only one that does not require intravenous injections and is, therefore, very suitable as a preliminary measure, which only involves breaking a capsule near the patient's nose until intravenous injections can be given. In the case of the sodium nitrite -sodium thiosulfate treatment, for instance, such injections require about 15 minutes. As amyl nitrite "Pearls" (small capsules containing liquid amyl nitrite) are placed in many first-aid kits by various companies that handle, store, or use hydrogen cyanide gas, it appeared advisable to investigate the explosion hazards of this material in air and oxygen. Accordingly, tests were made to determine the limits of flammability, temperature range of flammability of amyl nitrite saturated with air and with oxygen, and minimum ignition temperatures of this material in air and in oxygen.

Jan 1, 1952

By Thomas Varley

Data on the consumption of reagents used in .flotation during the year 1925, in metallurgical plants in the United States, are presented in this paper. Previous reports have covered the same subject for the years 1916, 1919, 1923 and 1924. The data contained herein show departures most radical from even the 1924 practice. Flotation has developed rapidly and on a more scientific basis than ever before. Perhaps more fundamental and useful data have been uncovered during the past two years than in all the years the art has been practiced.

Jan 1, 1926

By Charles W. Huggins

The Bureau of Mines investigated palygorskite, a natural asbestiform material, to accumulate knowledge that might serve as a foundation for future synthesis of a similar material. Unit cell, chemical analysis, DTA, TGA, optical constants, and electron microscopy data were obtained. Selected palygorskite samples of bettor than 97-percent purity were used to obtain this information. Chemical analysis revealed the following formula: (OH2)4 (OH)2 Ca0.01Fe0.02K0 .c3Mg2.10A12.00Si7.93020.3.91 H2O. The optical constants for sodium light are a = 1.522; S = 1.530; ?=1.533; biaxially (-). The following orthorhomibic unit cell constants were determined: ao = 12.690 A, Z = 2, bo = 17.857 A, Dx = 2.327. co = 5.207 A, Identical diffraction patterns resulted from the three palygorskite samples that were studied. X-ray, chemical, DTA, TGA, and optical data were compared with literature values for similar fibrous materials. X-ray diffraction lines were indexed. Several electron micrographs were made to compare the structures of palygorskite and attapulgite with that of chrysotile. The micrographs revealed extremely short laths for attapulgite, very long flexible laths for palygorskite, and tubular structure for chrysotile.

Jan 1, 1962

By M. G. Pelipetz

High-pressure, high-temperature hydrogenation of coal has been known and practiced for many years. A full' understanding of the mechanism in this process by which coal is converted to oil and gas must rest on a critical interpretation of the manner in which external variables influence the rate and the course of the coal-hydrogenation reactions. Same Bureau of Mines studies on the effect of temperature, catalyst, and rank of coal on these reactions have been published. The effect of pressure was not studied in this earlier work, and the effect of reaction time was complicated by the interruption of long reaction periods in order to refill the autoclave with hydrogen. It is the purpose of this paper to present data from more recent autoclave experiments that extend the results of Storch, et al, on the kinetics of coal hydrogenation. These data must be explained by any comprehensive theory of coal hydrogenation; their detailed evaluation, however, will be deferred until a later publication.

Jan 1, 1949

By Donald P. Schlick

This report presents a representative cross section of methods successfully used to ventilate continuous-miner places as well as various factors that should be considered when selecting auxiliary ventilating equipment. Line brattice can direct fresh air to the active face reasonably well, provided that adequate area for installation is available. Continuous mining equipment, however, often restricts clearances to such an extent that proper installation of line brattice is impossible. Consequently, in many instances face ventilation is inadequate; therefore, many methods of auxiliary ventilation for continuous-mining equipment have been developed and have been discussed in this study.

Jan 1, 1963

By E. D. Gardner

The Bureau of nines, in cooperation with the mining companies of the Southwest, is conducting an investigating to ascertain the safest and most economical explosives to use in metal mines, and to ascertain the best methods of blasting under various conditions. A part of this investigation has been a study of drilling and blasting drift rounds in metal mines. This paper covers one phase of work on drift rounds and discusses the methods of loading the individual holes of the rounds. The blasting tests, on which this paper is based, were made at the Copper queen Branch of the Phelps Dodge Corporation at Bisbee, Arizona.

Jan 1, 1927

By Steven J. Schatzel, William P. Diamond

Coalbed gas content measurements are commonly used in mine safety as well as coalbed methane resource assessment and recovery applications. Gas content determination techniques generally fall into two categories: (1) direct methods which actually measure the volume of gas released from a coal sample sealed into a desorption canister and (2) indirect methods based on empirical correlations, or laboratory derived sorption isotherm gas storage capacity data. Direct gas content determination techniques may be further. subdivided into quick-crushing and extended desorption methods. The quick-crushing methods are primarily used in mine safety applications outside the United States, but have also been used for resource recovery applications. Quick-crushing methods rely on crushing the coal sample soon after collection to release all the desorbable gas, thus significantly shortening the amount of time required for desorption measurements. However, some data useful for resource recovery applications are lost. Extended desorption techniques are most commonly used for resource assessment and recovery applications where information on desorption rates is useful for reservoir modeling, and for fundamental coalbed methane research. Extended desorption methods allow the gases in the coal sample to desorb under controlled laboratory conditions until a defined low desorption rate cutoff point is reached. The sample may then be crushed to measure the amount of gas remaining within the sample. Direct method techniques for gas content measurement are the focus of this paper.

By Joseph W. Town

The Bureau of Mines conducted studies related to SO2 air pollution to determine attritioning rates, SO2 sorption rates, and sulfur loads that could be obtained on commercial alkalized alumina sorbent pellets. Fluidized-bed attritioning rates ranged from 0.025 pct/hr for alkalized alumina with a crushing strength of 4 kg to 0.075 pct/hr for 0.5 kg crushing strength mate¬rial. Airlift attritioning rates ranged from 0.50 pct/hr for 3 kg crushing strength alkalized alumina to about 3 pct/hr for 0.5 kg material. Attritioning rates for the commercial alkalized alumina were comparable to those obtained for sorbent pellets prepared in the Bureau of Mines laboratory. Sorption rates were related to S02 concentration in flue gas, temperature, and presence of nitrogen oxides in the gas stream. Sorption rates at 300° C were 0.35 X 10-6 gS/gp/sec (grams sulfur per gram pellet per second) in 0.045 pct so, gas, 5.1 x 10-5 gS/gp/sec in 0.34 pct SO2 gas, and 65 X 10-5 gS/gp/sec in 10 pct SO2 gas. For the 0.34 pct S02 gas, sulfur loads of 0.10 gS/gp (the projected load for regeneration) were obtained in 47 min at 130° C and in 116 min at 300° C. The presence of either NO or NO2 in the 0.34 pet S02 gas increased the SO2 sorption rates 2 to 3 times at 300° C, but had no effect at 130° C.

Jan 1, 1969

By R. B. Schluter

The Bureau of Mines investigated the flotation responses of two copper-nickel ore samples from the Duluth Complex with the objective of recovering bulk sulfide concentrates. One of the ores studied was taken from a test pit; the other was taken from a test shaft. The samples were quite similar except that the pit sample analyzed 0.35 pct Cu and 0.11 pct Ni and the shaft sample analyzed 0.69 pct Cu and 0.14 pct Ni. Flotation responses were studied in both laboratory and pilot plant tests. Pilot plant flotation responses were similar for both samples resulting in grades of 12.2 pct Cu and 2.5 pct Ni for the pit sample and 12.2 pct Cu and 2.1 pct Ni for the shaft sample. Weight recoveries were 2.5 pct for the pit sample and 5.2 pct for the shaft sample. Copper and nickel recoveries for the pit sample were 87 and 62 pct, respectively, and 92 and 73 pct for the shaft sample. Both concentrates contained small but significant values of cobalt and precious metals. Cobalt recoveries were low--less than 40 pct for both concentrates. Precious metals contents of the concentrates were 1.59 oz/ton for the pit sample and 0.99 oz/ton for the shaft sample. Silver was the predominant precious metal by weight, but platinum and palladium represented the highest values.

Jan 1, 1980

By Alla D. Mah

The heat of combustion of TaC0.996 was determined by oxygen bomb calorimetry to be -302.8 ±0.4 kcal/mole. The corresponding heat of formation of TaC0.996 is -35.4 ±0.5 kcal/mole, and the calculated heat of formation of TaC1.00 is -35.5 ±0.5 kcal/mole.

Jan 1, 1965