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By Jr. Karr

The Bureau of Mines studied the influence of carbonization method, temperature, and carrier gas on the composition of eight different low-temperature tars produced from a Colorado subbituminous coal. A fluidized bed was compared with an entrained bed, temperature was varied from 500° C to 650° C, and external heating using recycle gas as the carrier gas was compared with internal heating using oxygen-containing gas. The entrained bed yielded significantly more m-cresol and m-ethylphenol, indicating that thermodynamic equilibrium was more nearly approached in the system. Increasing the temperature greatly increased the yield of benzenes and naphthalenes, while paraffins, olefins, and total tar acids were reduced. Using oxygen in the carrier gas decreased the yield of low-boiling phenols and increased that of paraffins and olefins at 650° C.

Jan 1, 1966

By L. J. E. Hofer

The Bureau of Mines determined rates of adsorption and desorption of methane as a function of particle size and temperature, using coals from the Pocahontas No.3 seam (lvb) from the Bishop mine of western Virginia, and the Pittsburgh seam (hvab) from the Pursglove No. 15 mine of northern West Virginia. For a given coal sample and temperature, the rate curves for adsorption and desorption are essentially the same when expressed on a fractional approach to equilibrium basis. The rates of adsorption and desorption increased eightfold as the particle size was decreased from 6-8 to 270-325 mesh per inch. The adsorption process appears to be diffusion controlled. Rate of sorption processes increased with increasing temperature; however, the amount adsorbed at equilibrium decreased.

Jan 1, 1966

Montana's coal reserves are estimated to be more than 120 billion tons, 24.6 percent of U.S. reserves. Montana's reserves are the largest in the nation. Coal fields are located throughout the state, primarily east of the Continental Divide. Three of the state's 17 coal fields have producing mines. Coal resources range from lignite to high volatile bituminous; however, most of the coal currently mined is subbituminous. Although Lewis and Clark mentioned the presence of coal along the banks of the Missouri River in Montana in 1805, the first major mine was not opened until 1867, at Chestnut, Montana, near Bozeman. The mine at Chestnut served Fort Ellis until the mine was bought by the Northern Pacific Railroad in 1883. By 1900, underground coal mining had developed throughout the state, primarily to supply fuel to the railroads. In the 1920s, large-scale surface mining began in Colstrip to fuel railroad steam engines. Currently, all coal mined in the state is produced from surface mines. The Office of Surface Mining granted the Montana regulatory program conditional approval April 1, 1980, followed by final approval February 1 1,1982. Montana's Abandoned Mine Lands Program was approved November24,1980, and its emergency program was approved August 18, 1983. A Federal Lands Cooperative Agreement was approved May 8, 1981.

Jan 1, 1992

By M. M. Tilman

The Bureau of Mines conducted research into the dispersion strengthening of lead by the coprecipitation method. Commercially available reagents in water solutions were reacted to form homogeneous precipitates of lead and aluminum compounds. The resulting precipitates were roasted to oxides and reduced in hydrogen to form mixtures of lead powder and alumina. The powders were isostatically pressed into billets which were extruded into rods. The rods were rolled into strip to provide material for testing. Alloys containing 0.5, 1, 2, and 3 nominal volume-percent A1203 were tested in short-time tensile tests and in tensile creep tests. An alloy of Pb-3 volume-percent A1203 exhibited an average tensile strength of 8,570 psi after rolling to 75-percent reduction at 125° C but had no measurable elongation. Alloys of lower A1203 content provided a better compromise between tensile strength and ductility. For example, an alloy of Pb-0.5 volume-percent A1203 had an average tensile strength of 6,590 psi with 9-percent elongation after rolling to 75-percent reduction at 125° C. Creep rates of dispersion-strengthened Pb-A1203 alloys were below 1 percent in 10,000 hours at stresses of 2,000 to 4,000 psi.

Jan 1, 1971

By Wesley T. Holmes II, Lloyd H. Banning

Electric - smelting studies were made on titaniferous materials obtained from the Klukwan and Snettisham , Alaska ; Choteau , Mont .; and Iron Mountain , Wyo . , deposits with the objective of determining the feasibility of producing pig iron and an enriched titania slag in one test series and pig iron alone in another test series . In addition , related studies were conducted to determine the amenability of Choteau crude ore to wet -magnetic separation and to determine the quality of steel that could be produced from the titaniferous pig iron . The continuous smelting tests were made in a three - phase , submerged - arc , electric furnace , and the laboratory steelmaking tests were made in a singlephase electric - arc furnace . A continuous , belt - type , wet - magnetic separator was used in conjunction with a ball mill and a spiral classifier in recovering titaniferous magnetite from the crude Choteau ore . Pig irons containing less than 0.05 percent phosphorus or sulfur were readily produced from the titaniferous materials ; iron recoveries ranged from 92 to 98 percent . The Choteau ore was ground to minus 65 - mesh to produce a concentrate containing 60 percent or more iron . The steel produced from the titaniferous pig iron was a high - quality product .

Jan 1, 1964

By John E. Pahlman

The Bureau of Mines investigated the feasibility of removing heavy metals from mineral-process waste streams by precipitation with lignochemicals and humic acids. Lignochemicals are by products from the paper industry, while humic acids are obtained by caustic treatment of peat, subbituminous coal, and lignite. These high-molecular-weight organic materials have many functional groups, which can coordinate and form innercomplex salts with heavy metals that are crystalline precipitates. Filtering of a humic-acid-or lignochemical-treated solution or waste stream containing these precipitates removes the heavy metal sequstrates. Tests were conducted with two lignochemical samples, three humic acid samples, lime (CaO), and sodium hydroxide (NaOH) in which increasing amounts of these additives were reacted with 50 mL of solution containing Fe3+ , Al3+, Cr3+, Pb2+, Cu2+, Cd2+, Zn2+, Co2+, Ni2+, Mn2+, and Hg1+. At the appropriate pH, greater than 90-and 99-pct removal was achieved for these 11 heavy metal ions from the 10-and lOO-ppm solutions, respectively, using lignochemicals and humic acids. Removal efficienC)' with these organic materials is better than that with CaO, especially for the more toxic ions, Hg1+, Cd2+, and Pb2+. Unlike the precipitates formed with NaOH or CaO, those with lignochemicals and humic acids are compact and noncolloidal. The volume of their sludge is sharply lower than that of the finely dispersed lime or soda precipitates; thus, their removal in settling tanks or by simple filtration is enhanced.

Jan 1, 1988

By A. R. Rule

This report describes preliminary studies by the Bureau of Mines to develop a procedure for extracting the fluorine from low-grade fluorspar ores in which the CaF2 particles are finely locked in the calcite matrix. A combination of flotation beneficiation and pyrohydrolysis is applied to recover and to liberate the fluorine. Flotation of a finely locked high-calcite fluorspar ore containing only 11.7 pct CaF2 recovered over 92 pct of the fluorspar at a grade of 51 to 52 pct CaF2. Pyrohydrolysis of the flotation concentrate liberated nearly 90 pct of the fluorine as aqueous HF. By this procedure over 80 pct of the fluorine contained in the original ore was extracted.

Jan 1, 1974

By Wing G. Agnew, Albert E. Long

"SUMMARY AND CONCLUSIONSTests conducted at Mount Weather indicate that clear water is the best bit coolant and cuttings-removal medium for diamond drilling. All of the mediums tested did show that drilling speed increased when drilling with the faster feed ratios (greatest pressure on the bits). In no case, how¬ever, did the increased drilling speed amount to over 16 percent, and even in a long hole the slight increase in drilling speed would be more than offset by the extra time consumed in setting up.Bit wear was excessive when lubricating agents were used, the most footage per bit was obtained when drilling with clear water in the normal manner, and the next best footage was obtained when drilling with circulated water containing no lubricating agent. The diamonds showed little or no wear in any of the bits, and all bits cut well throughout the tests. They were only taken out of service when erosion of the cast metal had progressed to the point where the diamonds were about to roll out. The lubricating agents evidently hold some of the cuttings in suspension, which in turn help to cut the rock but also wear the metal of the bit.No hard-matrix bits were tested, and it is possible that one or more of the lubricating agents might increase the efficiency of such a bit by keeping it sharp and doing away with the necessity of sharpening by sand blasting. Some tests are planned with hard-matrix-type bits and the same lubricating agents used in the tests under discussion, but it is realized that any drilling advantage gained by the bits sharpening themselves may but at least partly offset by excessive wear of the Pump parts."

Jan 1, 1945

By L. C. IlsLey, E. J. Gleim, F. CRAVEN

Electrical apparatus and circuits began to be used in mines about 50 years ago. A search of the literature on mining reveals that in 1882, umping was being done by electricity in some aines of England. One account tells of a small electric locomotive being used in 1882 "to drive eight corves loaded with coal" in a mine near Dresden. In an account of his visit to some English mines, en American in 1892 mentions that he saw underground electric signals, lights, pumps, hoists, and one revolving- cutter-bar 19wall mining machine,. Among the carl electrical installa- tions in the United States was an electric locomotive in the Lykens Valley Coal Co. mine at Lykens Valley, Pa., in 1887. In 1889 the Sperry electric coal digger was being tried out. Tarce mining machines were placed in the Prospect mine, East Palestine, Ohio, in 1890. An electrical pumping plant was put in oneration during 1892 in the Woodward mine of the Delaware, Lacka- rahma & Western Railroad Co. Thus we Almost coincident with the proposed use of this new servant in under- ground workings, came the thought of making it safe in gassy mines. find an account of a design for a protected stationary electric mine lamp proposed by Edison in 1831. Enclosed-type motors rere developed in the United States and shiped to English collieries about 1903. From those early beginnings there has been continuous progress until to-day one finds hundreds of pieces of specially designed electrical apparatus distributed in American coal mines and in mines of nearly all important coal-producing countries. Along with introduction of this equipment grew the idea of the necessi- ty of government aid, in standardization. In most coal-mining countries to- day the governments either directly or indirectly have a considerable in- fluence in guiding the design of electrical equipment intended for use in Pasay mine

Jan 1, 1933

By R. L. Hopkins

Some typical thiacyclopentanes and thiacyclohexanes were synthesized to provide reference compounds needed for the identification of sulfur compounds in crude oils. Two general methods of synthesis were employed: (1) cleavage of 2-alkyltetrahydropyrans with hydrogen bromide followed by the reaction of the resulting dibromoalkanes with sodium sulfide and (2) the catlyzed reaction of cyclic ethers or 1)4-or 1)5-alkanediols with hydrogen sulfide. Both methods produced mixtures of 2-alkylthiacyclopentanes and 2-alkylthiacyclohexanes with 2-alkyltetrahydropyran as the starting material. The structures of the reaction products were established by analysis for sulfur; desulfurization; gas-liquid chromatography (GLC); mass, infrared, and nuclear magnetic resonance (NMR) spectra; and an alternate synthesis. The synthesis of the cyclic sulfides contributed substantially to the identification of 10 members of this class of sulfur compounds in crude oil.

Jan 1, 1967

By M. B. Cooke, A. D. Bauer, E. W. Dean

The Bureau of Mines is collecting and analyzing representative samples of crude petroleum from all the producing fields in the United States , and the results are being published in a series of reports that are preliminary to the issue of a bulletin covering the entire survey . The bureau has recently completed a survey of crude oils from the Kansas district . In all 27 samples were collected and analyzed , under the direction of A. W. Ambrose , chief petroleum technologist of the Bureau. Valuable assistance was received through the cooperation of oil companies operating in the State , especially the Prairie Pipe Line Co. , and the Empire Pipe Line Co. The present report issued as Serial 2322 , on the Kansas crudes , forms the fifth of the series . Of the four previous papers , the first ( No. 2202 ) deals with crudes from the Eastern fields of the United States , the second ( No. 2235 ) with crudes from the Rocky Mountain district , the third ( No. 2290) gives additional data , cn viscosities and pour tests , for the crudes from these two fields , and the fourth ( No. 2293 ) covers the fields of northern Texas , northern Louisiana , and Arkansas . The details of the methods of collecting samples , making laboratory tests and interpreting results , have been discussed in these earlier reports . It has also been pointed out that the only adequate method of interpreting analyses of crude oils is to compare the individual reports with the analysis of some crude oil that is familiar to the operator . For this reason , no comprehensive discussion of the results of the Kansas survey is attempted, although some general statements may be made .

Feb 1, 1922

By Dean H. Ambrose

Computer programs are presented that provide mine electrical systems based on computer modeling for design and safety analysis suitable for large or small computer systems and handheld calculators. Bureau of Mines research has resulted in load-flow, fault, grounding, reliability, short-circuit, transient, and cable ampacity computer models that enable mine power system engineers to analyze their system or to design a system. This report describes the capabilities of the program.

Jan 1, 1984

By D. J. Parker

Ability to signal the hoisting engineer in shaft mines is of utmost importance from the standpoint of safety and economy. The problem of signalling from the cages and especially from the moving cages has received too little attention from mine operators; however, this problem has been given considerable thought and attention by at least one large metal-mining company in Utah which has devised successful, economical, and safe systems of signalling from the cage whether it is moving or at rest. A Report of Investigations on "Methods used in Utah for signalling mine hoists from moving cages," by C. A. Allen, then a metal-mining engineer in the Bureau of Mines, was issued in June, 1920. As this report contains interesting history of systems of signalling from moving mine hoists, and describes several systems then in use, it is here quoted in full.

Jan 1, 1929

By R. H. Nafziger

The Bureau of Mines evaluated 18 domestic titaniferous materials with widely varying compositions, mineralogy, and physical properties in electric-arc furnaces, Techniques were devised to recover both the titanium and iron values contained in these materials so that the reliance of the United States on foreign sources of higher grade ilmenites and rutile might be decreased. Most of the tested titaniferous materials responded well to lower grade or byproduct reductants, such as bituminous coals, charcoal, and coke breeze. Sufficient slag fluidity was realized by maintaining from 8 to 12 wt-pct iron in the slags; no contaminating fluidizers were required. Fluid slags containing up to 79, 70, and 54 wt-pct Ti02 were realized from east coast ilmenites, a rock ilmenite, and a titaniferous magnetite ore, respectively. A carbon-lined furnace shell is recommended for minimum slag contamination. Good results also were obtained during extended submerged-arc furnace tests.

Jan 1, 1980

By Carlton E. Brown

Impinger dust-counting methods are used by industrial hygienists for determining the number concentration of unhygienic siliceous dusts in industrial atmospheres. Various statements have been made regarding the size of the smallest particles revealed by the microscopic employed in such determinations. Published data on the subject are quite limited. This report presents information on the size of the smallest particles revealed by light-field and dark-field techniques applied to impinger and electric precipitator samples collected from experimentally established aerosols of silica dust and bituminous-coal dust. Size distribution and number concentration of particles of the various sizes in the aerosols were determined from samples collected by thermal precipitation simultaneously with the impinger and electric precipitator samples. The size of the smallest silica and bituminous-coal dust particles determined in the light-field counting method used was about 1./1, . There was relatively little variation in the values from 8 impinger and 33 A.-C. precipitator samples of silica dust and 13 impinger and 13 A.-C. precipitator samples of coal dust. The coefficients of variation of the values from the four sets of determinations were low, ranging from ± 7.7 to t 10 percent. This size of 1,14 is close to the limit of resolution of the microscopic method used and to various previously suggested values. The size of the particles determined in the dark-field counting method used was smaller than the size (about 0.28A ) of the smallest particles determined in the light-field, oil-immersion method used for the thermal precipitator samples.

Jan 1, 1951

By Edward F. Divers

Tills U.S. Bureau of Mines report briefly evaluates the advantages and disadvantages of basic dust control techniques presently used by U.S. coal preparation and mineral processing plants. These include ventilation, baghouse-type collectors, wet scrubbers, electrostatic precipitators, source control, sprays, good housekeeping, and personal protection devices. Two specific problems in these types of operations are also considered: dust collector system duct clogging, and control room dust control. Information provided in this report results from dust control research projects conducted by the Bureau at various coal preparation and mineral processing plants over the past decade to reduce workers' dust exposure. These studies indicate that plant ventilation systems normally provide the most cost effective method for dust control. Baghouses and scrubbers were also effective in specific applications, and examples of each are given. In extreme dust conditions, personal protection devices, such as respirators or the dust helmet, can also be highly cost effective.

Jan 1, 1990

By Walter W. Hyde

This paper describing the mining and preparation of sand and gravel for a number of special markets by the East Texas Gravel Co., Dallas, Tex., is one of a series being prepared on the subject by the United States Bureau of Mines. These articles are designed to disseminate technical information regarding the methods used. The cost tabulations represent operating expenditures only and not total production costs. It is recognized that publication of total production costs might in many instances cause embarrassment to individual producers as well as to the industry as a whole, but on the other hand, operating costs are essential to the technical discussion and study of the methods employed. The attention of the reader is specifically called to this differentiation in order that no misunderstanding of the scope of the cost tabulations shall ensue.

Jan 1, 1931

By Robert K. Koch, Henry E. Blake

Laboratory tests were made to determine if aluminum fluoride of commercial grade could be synthesized by reacting alumina hydrate with dilute ( 25 to 75 grams per liter of fluorine ) aqueous fluoride solutions . • Products containing up to 90 percent aluminum fluoride ( A1F ) were synthesized by reaction of alumina trihydrate ( A120 3H2O) with either dilute hydrofluoric acid ( HF ) or ammonium fluoride ( NHF) solutions , the ammonium fluoride solution resulting from ammonia ( NH ) desilication of a hydrofluoricfluosilicic acid ( HF - H₂ SiF ) solution . Fluorine recoveries of over 80 percent were obtained with either type of solution . The hydrated precipitates of AlF, and ( NH4 ) , A1F ( ammonium aluminum fluoride ) obtained by reacting hydrated alumina with these solutions were subsequently converted to anhydrous AlF, by controlled heating .

Jan 1, 1964

By Michael J. Friedel

As part of an investigation aimed at improving the health and safety and competitiveness of the mining industry, the U.S. Bureau of Mines evaluated the application of common offset radar profiling, using a 250-MHz ground-penetrating radar (GPR) system, for the detection of fractures in igneous rock. A series of radar reflection surveys were conducted to detect and delineate the extent of fracturing at various granodiorite and gabbro quarries and outcrops located in Minnesota. The application of radar profiling for detecting joints, sheeting fractures, shear zones, and depth to water table was demonstrated to be feasible with minimal processing. Radar reflection interpretations were verified by visual inspection of the rock mass and field mapping of local structure. The radar reflection section provides a simple, rapid, and cost-effective means for mapping of shallow (less than 10 m) small-scale fractures (greater than 0.25 cm) in igneous rock masses (characteristic of velocities between 0.061 m/ns for gabbro and 0.125 m/ns for granodiorite). Depth or distance estimates to fractures are within 10 pct of the actual, and time-shift compensation is necessary only when topographic irregularities exceed 30 cm.

Jan 1, 2010

By Slavoljub D. Maksimovic

At some coal mines, methane gas is released during raise drilling. At the request of the Mine Safety and Health Administration (MSHA), U.S. Department of Labor, the Bureau of Mines conducted ventilation surveys at different raise drill sites to assess various methods of reducing methane concentration. The resulting data indicate that raise drill shaft cavities are ventilated by air compressors, vacuum pumps, auxiliary blower fans, and free intake air from the surface. The compressors, pumps, and fans operate simultaneously or separately. At the bottom of the shaft cavities, ventilation is controlled by regulators and airlocks. Methane is monitored, measured, and periodically sampled on the surface, at the bottom, and at different levels in the shaft cavities. Maximum concentration of 3.5 percent was measured in one shaft in West Virginia. Air velocity down the raise drill shafts is always very low, Maximum recorded air down the drill stem was 3,000 cfm, which can be increased by adding air compressors. The best way to ventilate shaft cavities is through the simultaneous use of air compressors and vacuum pumps. If the methane concentration cannot be reduced with additional compressors, then the inside diameter of the drill rod should be increased, or larger pilot hole drill bits should be used.

Jan 1, 1981