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By L. H. Kalenowski

The metal lithium, its alloys, and its salts are becoming Increasingly important as industrial materials. Lithium metal, because of its great affinity for elements, such as nitrogen, hydrogen, oxygen, sulfur, phosphorus, carbon, and silicon, has become important for a wide variety of uses, ranging from purifying helium gas by removing the nitrogen to scavenging molten metals of undesirable impurities. The excellent fluxing properties of lithium salts have found increasing use in such applications as fluxes for welding aluminum and in lower melting ceramic glazes and coatings. Lithium chloride is one of the most hygroscopic salts known and is widely used as a dehumidifying agent. .About 17 lithium minerals are known. Four of these have commercial importance: Amblygonite, lepidolite, zinnwaldite, and spodumene. Spodumene is the most important source of lithium and lithium salts at present, but sizable deposits of amblygonite occur in the pegmatite area of the Black Hills of South Dakota. The size and nature of these deposits preclude the, possibility of, any assurance of an adequate supply of amblygonite for an operation processing only this mineral. Frequently spodumene and amblygonite occur associated in pegmatite minerals. Preliminary investigations indicate that a simultaneous recovery of spodumene and amblygonite can be made by froth flotation. A single process for treating spodumene and amblygonite or mixtures of thorn, would make possible more use of amblygonite as a source of lithium and obviate the separation of spodumene and amblygonite when they occur together.

Jan 1, 1952

By Arden D. Fugate

The Federal Bureau of Mines conducted extensive studies on solid-state defluorination (laboratory scale) and tests on molten defluorination (intermediate scale) of siliceous fluorspars. The studies were made to develop a pyrohydrolytic process for liberating fluorine from offgrade fluorspars. Test results showed that more than 90 percent of the fluorine can be evolved by solid-state defluorination at 1,300° C., and more than 97 percent can be liberated by molten-state defluorination at 1,420° C. Solid-state defluorination conditions were established by conducting tests on mixtures of ceramic-grade fluorspars and high-purity silica flour. Pelletized mixtures were defluorinated under varying conditions of time, temperature, and relative concentrations of silica, calcium fluoride, and water. The effects of adding various amounts and combinations of aluminum oxide and iron oxide on defluorination were also studied. Investigations of solid-state defluorination indicates that the following two reactions are involved: 2CaF2 + 3SiO2 = 2CaSiO3 + SiF4, and CaF2 + Sio2 + H20 = CaSiO3 + 2HF, The second reaction is dominant, although significant defluorination can be achieved by the first reaction.

Jan 1, 1961

By R. P. Walters, M. J. Lynch, D. R. Flinn

The Bureau of Mines evaluated tthhee feasibility of substituting platinum- coated metals for bulk platinum shapes as a means for conserving platinum . Platinum coatings were prepared using four different methods of electrodeposition , then tested and evaluated . In order for platinum coatings to be useful in process environments , they must be thick , adherent , stress - free , and pore - free . The Bureau evaluated direct - current , current reversal , cathode shielding , and pulsed- current plating techniques for producing a pore-free platinum electrodeposit from a molten cyanide bath . Aqueous corrosion tests of Fe - 10Cr substrates coated with approximately 25 μm of platinum showed that pulse plating yielded the most corrosion- resistant and , hence , the most pore -free coatings . The morphology of coating cross sections was in all cases columnar . The average grain size of pulse -plated deposits was independent of thickness , while all other plating techniques produced grains that increased in size as the coatings became thicker . It is believed that the constant grain size in the pulse - plated deposits resulted from better mass transport during the electrodeposition .

Jan 1, 1965

By Robert F. Randolph, Dana C. Reinke, Richard L. Unger

Purpose The NIOSH Hearing Loss Simulator is a software training and communication tool for promoting hearing loss prevention. It allows a user or trainer to demonstrate the effects of noise exposure on hearing without experiencing an actual noise-induced hearing loss. Estimates of the effects of different levels of noise exposure are based on the American National Standard Determination of Occupational Noise Exposure and Estimation of Noise-Induced Hearing Impairment, otherwise known as ANSI S3.44. This standard specifies the predicted hearing loss for noise-exposed populations of individuals based on risk factors that include gender, age, sound levels (in A-weighted decibels or dBA), and years of exposure. Algorithms specified in the standard were derived from empirical studies of populations that had no exposure to loud noise and other populations that had experienced various levels and durations of noise exposure. This manual explains the major objectives that can be addressed with the simulator and training scenarios that can be applied to real-life, real-worker scenarios. The majority of this guide explains the simulator's functions in detail. Simulator users are encouraged to read this manual while learning how to run the software. [ ] Training Objectives The main objective of the Hearing Loss Simulator is to increase motivation for taking effective hearing prevention action by demonstrating simulated noise-induced hearing losses. [The Simulator can also help teach the following facts about hearing loss. Hearing loss is affected by noise levels. Hearing loss worsens as the noise exposure duration increases. Hearing loss can become permanent. Hearing loss makes it harder to hear what others say. Most hearing loss is not caused by age. Speech is made up of both low and high pitch sounds. Hearing loss due to noise makes it harder to hear high pitch sounds. Hearing loss due to noise has less of an effect on hearing low pitch sounds.]

Jan 3, 2008

By W. H. Kerns

The Simon & Coles manganese deposit in Sherman Valley, Bedford County, Pa., was investigated by the Bureau of Mines during the fall of 1942. Two churn-drill holes; 65 and 75 feet deep were bored, and 8 channel samples were taken. Manganese occurs at this property in the form of psilomelane and manganiferous iron as replacement of the red sandy shale of the Much Chunk-formation. Two cars of manganese ore had been shipped by the owners in 1940, of which one averaged 10.9 percent manganese and the other 21.3 percent manganese. One car of hand-sorted manganese ore that averaged-45 percent manganese was shipped in 1942.

Jan 1, 1948

By William H. Lesser

A recent survey of pumping plants in the anthracite region of Pennsyl¬vania showed that more than 90 percent of the pumps in use are the horizontal centrifugal types (1).2/ This report on the design and operation of centrifugal pumps should be helpful to engineers of the region who must select pumps that are best suited to particular pumping conditions in anthracite mines. Before a centrifugal mine pumping plant is designed, the special features of the pumps that may be used should be considered, especially when low repair costs and continuous operation during flood periods are prerequisites, and when acid mine water is to be pumped. Two important advantages of a centrifugal pump are that the flow is continuous and that it can be throttled without developing excessive pressure or overloading its driving unit.

Jan 1, 1950

By James S. Browning

Heavy liquids have been used to separate minerals of different specific gravities for many years.4 5 6 7 8 9/ The method permits substantially quantitative evaluation of a variety of minerals and requires much less time than the usual methods of chemical analysis. This Bureau of Mines investigation was conducted to determine the applicability of heavy liquid mineral separation to the evaluation of certain spodumene and kyanite ores, prepared mixtures, and plant products. After careful standardization of the particular mineral and associated gangue, estimates of chemical analyses could be obtained from results of heavy liquid separations.

Jan 1, 1960

By E. S. Shedd

Misch metal was electrowon from a treated bastnasite concentrate in a REF3-LiF-BaF2 electrolyte at 950° C. The metal was prepared and tapped from a 1,000-ampere cell, and nearly 100-percent utilization of the rare-earth oxide was achieved. Prolonged operation in a smaller cell (40 amperes) indicated that the composition of the misch metal product was reasonably constant, and no significant increase of impurities, with the exception of carbon, was noted.

Jan 1, 1970

By C. Lorimer Colburn, Spencer P. Howell

"Numerous accidents are still being reported that have resulted from the delayed explosions in drill holes. Some of these accidents have boon due to retarded burning of the fuse, causing the charge to explode after the miners had returned to the face, but the majority have been caused by the minors drilling or picking into unexploded explosives, either in unexploded bolas or in broken rock. Although the industry has been cautioned by the Bureau of Mines, manufacturers of explosives, and other agencies regarding the care that is necessary in the handling of explosives, yet reports of these accidents are still being received and many of the accidents are fatal, They occur in spite of the best efforts of the mine officials and men, but many of those that have been reported could have been avoided if the following precautions had been observed:Misfires should not be approached even for the purpose of inspection until three hours have elapsed if fuse was used, and ten minutes if electric detonators or electric igniters were used. These are minimum recommendations. It would be preferable to allow a longer time, for fuses have been known to hang fire for twelve hours."

Aug 1, 1920

By P. T. Brooks

A process for extracting 69 percent of the vanadium from weathered Nevada dolomitic shale containing about 1 percent V205 was developed on a laboratory scale by the Bureau of Mines. The process essentially is comprised of salt roasting, leaching with dilute sulfuric acid, solvent extraction, and precipitation of vanadium as ammonium metavanadate. Carbonaceous unweathered shale was less amenable to treatment. A preliminary cost estimate for mining and processing 1,500 tons per day of weathered shale indicated a production cost of about 1 dollar per lb of V205. Considering recent sales at nearly $1. 75 per lb of contained V205, larger scale testing to obtain more definitive process design and evaluation data may be warranted.

Jan 1, 1974

By H. E. Powell

A solvent extraction procedure was developed on a laboratory scale for recovering trisodium phosphate, zinc, and iron from waste phosphate sludge as separate products. The sludge was dissolved in hydrochloric acid, and iron was extracted as ferric chloride by isopropyl ether. Zinc was extracted by di-2-ethylhexyl phosphoric acid in kerosine. The efficiencies of the one-and two-stage extractions ranged from 98 to nearly 100 percent. Trisodium phosphate was recovered by crystallization from the raffinate. The value of two marketable products is considerably more than than the costs of the major reagent. The process was developed to permit recycling of values in this waste and to consequently reduce stream pollution from this source.

Jan 1, 1972

By Robert C. Gabler

Three filter cloth fabrics commonly used in drains for coal waste embankments were tested by the Bureau of Mines for clogging behavior and deterioration under simulated field conditions. The objective was to provide guidelines for the mining industry for the proper selection and use of filter cloths to assure safer embankments at mine waste disposal sites. The filter cloths were tested with three coal waste samples in stand-pipes used to simulate coal mine waste disposal environments. Two of the cloths showed a tendency to become clogged with fines from the wastes. One waste caused clogging by precipitating an iron-silicon compound on the test cloths. No apparent cloth deterioration resulted from exposures to the simulated coal waste environments. (The exposures ranged from 2 to 12 months.) In other tests, exposures to waters in the pH range of 2 to 12 and to reagents used in coal-preparation plants resulted in insignificant or no deterioration, as measured by tensile strength. However, long exposures to sunlight (ranging from 4.6 to 6 months) caused major deterioration in two of the cloths (86-and 98-pct losses in tensile strength) and slight deterioration in the third cloth (9-pct loss in strength).

Jan 1, 1984

By A. F. Colombo, R. T. Sorensen, D. W. Frommer

The Bureau of Mines developed a flotation method for concentrating spiral tailing produced from pilot plant tests on the Champion mine ore fines . The feed material contained about 49 percent Fe and 15 percent SiO2 and was posed mostly of specular hematite , muscovite , and chlorite . Bench- scale , batch flotation research developed a reagent suite composed of tall oil - fatty acid , fuel oil , sulfuric acid , sodium fluoride , and sodium silicate for recovery of iron minerals in the froth product . Concentrate made with the reagent suite contained 87.3 percent of the iron and analyzed 65.6 percent Fe and 1.9 percent SiO2 . Continuous flotation tests were made with a nominal feed rate of 400 lb /hr , but without middling recirculation . Using nearly the same amount and complement of reagents as in the batch tests , three similar continuous tests gave concentrates averaging 63.9 percent Fe and 3.1 percent Sio while recovering about 86 percent of the iron .

Jan 1, 1964

By M. Clair Smith

The Sweetwater, Castro, Trinidad, New London, and Hilltop chromite properties are situated within an area 8 miles long and 1 mile wide between San Luis Obispo city and Morro Creek, San Luis Obiso County, Calif. Development work at this group of mines was a part of a long-range project by the Bureau of Mines to develop strategic mineral reserves in the United States in accordance with the Strategic Minerals Act of 1939. The junior author of this report participated in the preliminary examinations made in 1941 of the chromite deposits that later in the same year were the subject of more intensive investigation under the immediate supervision of the senior author. The ore occurs in lenses and kidneys in masses of dunite contained in large poridetite areas. Production has boon in the form of lump ore and concentrates from disseminated ore. Work by the Bureau of Miner included surveying, mapping, trenching, sampling, and assaying. It is summarized separately in the text under the name of each mine investigated. The report gives a brief history of the district, describer the concentrating plant of the Castro Associates, and gives detailed results on sampling and assays at the various proportion.

Jan 1, 1951

By A. W. Fahrenwald

As an aid to studies of grinding, a batch laboratory classifier and elutriator has been developed at the U. S. Bureau of Mines Metallurgical Field Office at Moscow, Idaho, in cooperation with the University of Idaho. It is designed for use in conjunction with other batch laboratory apparatus, such as ball mills and flotation machines. It is shown in Figure 1. Description and Operation of Batch Laboratory Classifier The classifying column is a cylinder 4 feet 2 inches long, of 5 3/4-inch inside diameter, and terminates at its top in a cone or funnel 18 inches in diameter at the overflow elevation. The pressure chamber is of the same diameter as the classifying column, and has a conical bottom; it is provided with two openings, one in the cylindrical portion through which water is admitted, and the other, a small drain hole, in the apex of the conical bottom. The two compartments are bolted together and communicate with each other through the medium of a constriction plate provided with 3/16-inch holes spaced 1/2 inch apart. Constriction plates having any other percentage of opening may be substituted as the needs demand water is admitted to the compartment below the constriction plate at constant pressure. The volume of eater admitted is controlled with a valve. It should be mentioned that the classifying column at the bottom, just above the constriction plate, is glass.

Jan 1, 1929

By Ernest V. Deshayes

The Colorado Minerals Co. calcite properties in Archuleta and Hinsdale Counties, Colo., (fig. 1) were examined by Bureau of Mines engineers in 1943. The demand for optical calcite during the war prompted the examinations and resulting development programs on the Meadows and Seavy ranch properties near Pagosa Springs, Archuleta County. Development was begun on the Meadows property in November 1943 and continued to the Seavy ranch property. The work consisted of stripping the overburden from the calcite areas and excavating pits and trenches with a bulldozer. The pits and trenches exposing the most promising calcite veins were then deepened by hand, and one shaft was sunk to a depth of 30 feet. A total of 36 trenches and 9 pits were excavated by bulldozer and. hand methods (figs. 2, 3, and 4). The calcite deposits occur as veins and irregular bodies filling fractures in the Mancos shale of Cretaceous age. The fractures persist for considerable distances along the strike, although the calcite filling may not be continuous for more than a few feet. The widths of individual veins range from a few inches to several feet. The calcite crystals uncovered at the surface and in pits, trenches, and shafts were found to be unsuitable for optical purposes because of fracturing and color in the crystals.

Jan 1, 1949

By S. R. B. Cooke, J. Bruce Clemmer, F. P. Diener

"The limestone deposit utilized by one of the plants of the Universal Atlas Cement Co. is covered in part by a stratum of cherty limestone. If this overlying deposit could be utilized by removing the excess of chert economically, quarry costs could be reduced and the amount of rock economically available would be increased greatly. On account of the distribution of flint and limestone, a product fairly free of flint can be obtained until the quarry face is about 50 or 55 feet high. As the face is worked farther back into the hill, the comparatively clean stone is overlain with a constantly increasing amount of high-flint limestone. If this flint remained with the limestone, there would be a prohititively high silica ratio in the finished cement; if the flinty layer were removed as overburden a very large tonnage would be handled and much good stone lost. Consequently it was felt that means should be devised for separating the flint from the limestone after it reaches the plant.The investigation was undertaken by the Mississippi Valley Experiment Station of the United States Bureau of Mines in cooperation with the Universal Atlas Cement Co. and the Missouri School of Mines and Metallurgy, Rolla, Mo.CONSIDERATION OF PROCESSESMany schemes for the separation of Minerals are based on differences in the specific gravities of the minerals to be separated. In this case the flint has a specific gravity of approximately 2.62 while the limestone averages about 2.70. This differential is not large enough to permit separation by any method based on specific gravity. Furthermore, all the limestone particles in any given sample are not alike; usually about 10 percent of them have a specific gravity the same as, or lower than, the flint."

Mar 1, 1935

By Eugene Frey

"INTRODUCTION The ti taniferous-iron deposits in the Iron Mountain area of the Laramie Range, and particularly the Shanton deposit, were examined by several engineers. 3/ of the Bureau of Mines during 1942, 1943, and 1944. A dip-needle survey also was made early in 1945. 4/ Interest in this property has increased as a result of the exploratory work completed by the Bureau in 1944 on the Iron Mountain deposit, 6 miles northeast of the Shanton property.ACKNOWLEDGEMENTSIn 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 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 due to Paul T. Allsman, chief, Salt Lake City Division, Mining Branch; James A. Marsh, district engineer; Paul E. Pesonen, Frank L. Wideman, and Frank H. Gunnell, Bureau of Mines engineers; and to S. R. Zimmerley, chief, Salt Lake City Division, Metallurgical Branch, for analyses of samples."

Aug 1, 1946

By Halagowder Devaraj, Mostafa Sheykhnazari, Veer P. Bhavanandan

"A sensitive colorimetric assay for detecting mucins and glycoproteins rich in 0-glycosidically linked saccharides is reported. The method combines the susceptibility of N-acetylgalactosamine terminating 0-glyco idically linked saccharides to P-elimination with the Morgan-Elson reaction for N-acetylhexosamines with free reducing ends. All mucin and mucin-type glycoproteins but none of the serum-type glycoproteins tested resulted in characteristic color production. All mucins tested gave linear responses in the range 5 to 200 ""g and the assay was also adapted to the microscale involving the use of 96-well microtiter plates. The microassay in which the volumes of samples and reagents are scaled down 2.5-fold was particularly useful in monitoring of mucins, in the presence of other glycoconjugates, in large numbers of samples obtained during fractionation procedures. Cesium chloride, cesium bromide, potassium thiocyanate, and various detergents do not interfere with the colorimetric determination. Guanidine hydrochloride, cesium triftuoroacetate, and B-mercap- . toethanol decreased color by 30 to 45%; however, the interference was not serious to prevent the use of the method for detection of mucins in their presence. The use of the method for the specific detection of mucin during fractionation by gel filtration and density gradient centrifugation of cystic fibrosis sputum samples is demonstrated. Mucins are an important class of biomacromolecules whose structure-function relationship is poorly understood (1,2). The investigations of mucins are hampered by difficulties in purifying these very large size molecules which appear to avidly bind other components of the mucus (3,4). One of the problems during purification is the specific detection of mucins. For example, during the various purification steps, the fractions containing mucins are typically detected by assaying for neutral sugars (hexoses) (5,6), for sialic acids (7), or for periodate oxidizable saccharide units (8). However, these methods are not entirely satisfactory because neutral sugars, sialic acids, and periodate-oxidizable saccharides are also components of other glycoconjugates. In addition, the neutral sugar and sialic acid measurements are also subject to interference from high levels of proteins and nucleic acids."

Jan 1, 1990

By R. E. Brewer

Published investigations show that many different chemical reagents have been used in determining the constitution of coals , but only a few studies have been applied directly in evaluating the effects of such reagents on the carbonization products of coal , Most of the treatments have been so drastic that any permissible conclusions that may be drawn are inferential in respect to any favorable effects on the yields and composition of the usual carbonization products .

Sep 1, 1943