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By H. C. Miller

The removal of the mud sheaths that are deposited against the faces of productive oil sands during rotary drilling is one of the important problems confronting operators, especially in semidepleted fields where formation pressures are low. Unless the mud sheaths behind the perforated oil strings and liners are removed and the sands exposed, oil cannot enter the wells. Consequently much oil that otherwise might be produced from low-pressure sands is trapped and never recovered. Various types of perforation washers, down swabs, and agitators are used at present for breaking down the mud sheaths and removing the disintegrated clay particles from wells after the perforated Wipes have been inserted. Mechanical methods for removing mud sheaths are :quite satisfactory, but prompted by the request of certain .operators in the California oil fields Bureau of Mines engineers have conducted a series of laboratory tests with the view of developing a chemical method for removing mud sheaths in oil wells that will be applicable to field conditions. This report describes the laboratory work and deals generally with a chemical method for removing the mud sheath, cake, or plaster deposited against the face of oil sands in drilling wells end in wells that, on being shut in temporarily during periods of overproduction of oil, are conditioned for the shutdown .period by filling the well opposite the producing formations with mud fluid. The method described in this report was devised in the San Francisco laboratory of the Bureau of Mines and, as far as the writers have been able to determine, differs from any chemical method ever used in actual wells. The method proposes to add a small amount of calcium carbonate (preferably pulverized limestone) to the mud fluids before they are introduced into the wells so that the resultant mud sheaths will be susceptible to disintegration by acid solutions when it is desired to expose the faces of the oil sands in the wells.

Jan 1, 1934

By R. C. Hickman

"INTRODUCTION .As part of its spot drilling program, the Bureau of Mines core-drilled seven holes on the Alexander and Barber properties in Spartanburg County, S. C.Extensive surface float and outcrops of sillimanite schist on these properties appeared to justify drilling, which did not prove satisfactory, however, owing to the spotty occurrence of the schist bodies and the poor core recovery in the decomposed schist.ACKNOWLEDGMENTSIn 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, Oliver C. Ralston, chief, analyzes samples and performs beneficiation tests.This project was under the immediate supervision of Mitchell H. Kline, chief, Raleigh Division, Mining Branch, Bureau of Mines.LOCATIONThe Alexander and. Barber properties are in the southern part of Spartanburg County, S. C. The Alexander property is about 5 miles cast of Woodruff. It is reached from Woodruff by driving east 5 miles on a macadam road to the intersection with an unsurfaced road near Unity Church. The farm house on the property is 0.4 mile north on this road. The sillimanite outcrop is in a field approximately 1,200 feet east of the farm house. The Barber property is about 2 miles north along the unsurfaced road that passes the Alexander property."

Sep 1, 1947

By R. Agarwal

The in-situ stress field was determined, using the overcoring technique, at two underground sites at the Pea Ridge Mine, Sullivan, Missouri. At one of the sites in magnetite, the three dimensional stress field showed the largest principal stress to be compressive (-4564 psi), nearly horizontal and closely parallel to the strike of the orebody. The smallest principal stress was also compressive (-2047 psi) and nearly vertical. Considerable difficulty was experienced in drilling porphyry rock at the second test site in the host rock. Only one hole was drilled at this site. The secondary principal stresses obtained in the porphyry are -9464 and -4945 psi, respectively. The-test site in magnetite is located at a depth of 2505 feet whereas the site in porphyry rock is at 2475 feet. The vertical stresses: due to overburden loading at these sites are -3590 and -2782 psi, respectively. Field determined values of the vertical stress are -2207 and -5098 psi, respectively. The variance; between the two sets of values is most likely attributable to the orebody formation and the differences in the modulii of the host rock and the orebody.

Jan 1, 1977

By J. R. White, S. W. Lambert, C. M. McCulloch

Examination of several coalbeds in Walker County, Ala., Cambria, Greene, and Fayette Counties, Pa., and Raleigh and Wyoming Counties, W. Va., indicates that cleat orientations are similar throughout a vertical sequence of strata. Studies of cleat orientation were carried out in underground mines that are operating in separate coalbeds vertically above one another. The data show that over a vertical separation of 100 to 400 feet, the average difference in coal cleat orientation between mines is 04° for the face and 08" for the butt cleat. Variations of coal cleat direction between coalbeds examined in strip-mined areas show similar values. Cleat orientations measured at outcrops agree well with the directions measured underground, suggesting that the amount of vertical separation between coalbeds has little effect on the resulting differences in cleat directions. The largest variation of cleat directions between adjacent coalbeds occurs where a large horizontal distance separates two sample locations. Cleat orientations for deeper coalbeds are most reliable where the data are taken from directly above.

Jan 1, 1976

By A. Adams

The quality of hafnium metal produced by the Kroll process depends upon the purity of the hafnium tetrachloride. This investigation of methods for purification of hafnium tetrachloride was undertaken to aid in producing a higher purity hafnium metal than is currently produced by the Kroll process, The quantities of metallic impurities in hafnium metal were decreased by contact with molten alkali-metal chloride salt. Contact was achieved by a semicontinuous process of bubbling gaseous hafnium tetrachloride through a molten salt bath or by a batch process, first fusing the tetrachloride with a combination of alkali chlorides and then heating the mixture to sublime the hafnium tetrachloride. Low-melting mixtures of sodium, potassium, and lithium chlorides were used to purify hafnium tetrachloride. About 30 percent of the initial hafnium tetrachloride was trapped during purification with alkali- metal chloride salts. The 95-percent confidence limits (6)4 for the amount of oxygen decrease 60 and 34.3 parts per million when the batch purification is combined with a reduction so that both take place in the same equipment,

Jan 1, 1961

By Russell. Paul L.

"INTRODUCTION Preliminary reports by Bureau of Mines engineers 3/ and by the Federal Geological Survey 4/ suggested that exploration would discover substantial reserves of minable ore in the Contact mine, Grant County, New Mexico. During February and March 1943, a sampling program was conducted on this property under the direction of the author. This was art of a general survey of the manganese districts of southwestern New Mexico.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 national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as practicable soon as after its conclusion. The Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocer, chief, analyzes samples and performs beneficiation tests. Both these branches are under the supervision of Dr. S. Dean, assistant director. With respect to this report, special acknowledgment is due to C. H. Johnson, district engineer for New Mexico, and E. D. Gardner, regional engineer, and his staff, of the Central Region of the Bureau of Mines at the time of this work in 1943; also to Kenworthy, metallurgist at the Rolla. Mo., Laboratory of the Bureau of Mines, for work on beneficietion of the ore, and Sherman K. Neuschel, geologist of the Federal Geological Survey, for assistance in interpreting geological data at the project."

Oct 1, 1946

By W. D. Mcmillan

Soapstone is the term applied to an impure, massive, soft rock with a greasy feel. It is of variable composition, consisting chiefly, however, of talc, tremolite, and chlorite. Although limited quantities of soapstone are used as building material, in fireplaces, and in the manufacture of laundry tubs, sinks, laboratory-table tops, and-oven and furnace blocks, the principal part of the production is ground for use in roofing paper, insecticides, and as a filler in asphaltic paints.

Jan 1, 1949

By F. S. Kendorski

This report covers the work on developing criteria for determining when a hazard exists when mining stratified mineral deposits beneath bodies of surface water. The nature of water bodies is considered, the disturbance to the strata induced by mining is described, inundation case histories reviewed, reasonable water inflows derived, and methods of mining to prevent or minimize the hazard are presented. Criteria are given whereby effected industries and agencies can recognize a potential hazard and plan a mine accordingly, releasing considerable mineral reserves otherwise considered unminable.

Jan 1, 1979

By James S. Browning

The Bureau of Mines conducted laboratory batch and pilot plant flotation tests to determine the technical feasibility of recovering commercial-grade mica from a California micaceous schist. Best results in the laboratory batch tests were obtained using sodium carbonate and sodium silicate for pH control and quartz depression, and a combination of fatty acid and cationic reagents as the mica collector. In continuous pilot plant flotation tests, an alkaline fatty acid-cationic method recovered about 70 percent of the mica in a concentrate analyzing 95.6 percent mica.

Jan 1, 1965

By Foster Fraas

A separator for minerals of low magnetic susceptibility and fine particle size in a water suspension is described. A ring-shaped matrix of ferromagnetic fragments rotating so as to pass successively through magnetic-field and field-free regions provides for the separation. Application is illustrated in the separation of hematite and ilmenite from quartz.

Jan 1, 1966

By D. D. Fischer

Recovery and separation of molybdenum and rhenium from a process solution was accomplished by a technique developed by the Federal Bureau of Mines involving a combined solvent extraction and activated carbon adsorption procedure. The processing sequence required treatment of the solution with S02 to reduce the chlorate ion and adjust the pR prior to solvent extraction of molybdenum and rhenium with a tertiary amine. Molybdenum and rhenium were stripped from the organic phase with an NH40H solution, and the strip solution was then passed through activated carbon to preferentially adsorb the rhenium. After washing entrained molybdenum from the column with a brine solution, rhenium was eluted with an MeOH-H20 mixture. The activated carbon was regenerated with water. Molybdenum was recovered as (NH4)6Mo7024 by evaporating the column effluent. Rhenium in the column eluate was reextracted with a tertiary amine, stripped from the organic phase with dilute NH40H, and recovered as NH4Re04 by evaporating the strip solution. The final (NR4)Re04 product contained < 80 ppm impurities. Sodium sulfate was crystallized from the first solvent-extraction raffinate by lowering the solution temperature to 0° C. Precious metals contained in the original process solution were adsorbed onto the activated carbon.

Jan 1, 1975

By R. V. Ramani, V. T. Burgos, J. A. McClay

Model testing is a two part operation; first, to assure the valid¬ity of the mathematical statements and second, to evaluate the accuracy of the computer model for predictive purposes. Verification of both the conceptual and computational aspects can be achieved through the use of input data for which output results are available for comparison. In this dissertation, two test problems were selected for model testing from the Economic Evaluation Reports of the U.S. Bureau of Mines, Process Evaluation Group. Verification Data Set I Input data for this test was selected from an economic analysis of a hypothetical 1,056,000-ton-per-year mine in a 48-inch bituminous coal seam (Process Evaluation Group-Report No. 72-27, 1972). The mine was scheduled to operate five days per week, three shifts per day, 220 days per year with an estimated life of 20 years. Coal reserves covered an area of 6.4 square miles with an expected recovery rate of 70%. Production was achieved through 4 continuous miner sections with an average production rate of 400 tons per shift. The cost summary in the report included a breakdown of equipment and labor requirements. A depreciation schedule listed the expected capital expense per year of operation, assuming capital replacement with identical units and no change in the unit cost. Supply and oper¬ating costs were listed in both gross annual figures and cost per ton of production. The operating and investment costs were projected over the 20 year mine life and a discounted cash flow analysis performed to determine

Jan 1, 1975

By Wilbert J. Huff

The Explosives Division of the United States Bureau of Mines makes certain laboratory and field investigations that deal with explosions, explosives, ignition, and combustion, together with many related problems, such as the cause and prevention of fires, and certain fundamental scientific questions bearing upon the determination of the chemical and physical mechanisms underlying some of the important phenomena encountered. Its work on explosives has been particularly directed toward determination of the chemical and physical characteristics of explosives designed for use in coal mines and in a more limited way to those used in metal mines, tunnels, quarries, and other engineering operations. This testing is handled by two units of the Explosives Division, as follows:

Jan 1, 1937

By A. E. Harak

To determine the retorting characteristics of a column of mine-run, ungraded oil shale ranging in size from fines to pieces weighing as much as 5 tons, a 150-ton batch retort was designed and constructed at the Laramie Energy Research Center, Laramie, Wyo. The retort vessel is 45 feet high by 11-1/2 feel in inside diameter and is supported in a 92-Foot-high steel superstructure. Mine-run shale from the Bureau of Mines facility near Rifle, Colo., assaying about 25 gallons of oil per ton, is currently being used as the test shale. To date, three runs have been completed. Results of the second and third runs are reported in this paper. The two runs considered in this report are the first of a series of nine to determine operating conditions that will yield maximum oil recovery from a column of mine-run shale. Variables studied :ire the oxygen content of the retorting gas and the space velocity of the retorting gas expressed as ft3 gas/ft3 bed/min. Oil recoveries for the two runs reported are 62.2 volume percent of Fischer assay for the run using higher oxygen and space velocity, compared with 39.3 volume-percent when less oxygen and a Lower space velocity were used.

Jan 1, 1971

By Jr. Sharkey

The Bureau of Mines investigated gases from flash and laser irradiation of Pittsburgh seam (hvab) coal to determine the action of high temperatures on coal. Temperatures in excess of l,000° C were reached with both types of irradiation. Craters about 300 microns in diameter were produced in the coal with millisecond pulses from the laser unit rated at 1.7 joules&apos; output. Gaseous products from laser and flash irradiations in vacuum contained 21 and 8 percent acetylene, respectively. Diacetylene, vinylacetylene, and other products to molecular weight 130 were indicated in the mass spectrum of the gas from the laser study. Single experiments were also conducted in which the laser energy, particle size of the coal, and atmosphere were varied. The results indicated that the distributions of products obtained from the flash and laser irradiations of coal were different from that produced in high-temperature carbonization.

Jan 1, 1966

By Elton L. Litchfield

The Bureau of Mines determined minimum energies for direct initiation of expanding gaseous detonation waves in acetylene-oxygen mixtures. Composition limit ranges for the initiation of detonation with fixed energies have been compared to data in the literature. Assuming that the stored electrical energy is completely converted to thermal energy, the agreement between the energy of primary explosive initiators and the energy of electrical discharge initiators was good. Minimum energies for initiation of detonation in the most sensitive composition (40 percent C20 plus 60 percent 0 2) were: 0.64 joule at an initial pressure of 1/4 atmosphere, 5.0X10-2 joule at 1/2 atmos¬phere, and 3.7X10-3 joule at I atmosphere. Fuel concentrations in mixtures initiated to detonation by 4.9X102 joules ranged from 10 to 65 percent C2H2 at 1/4 atmosphere, 10 to 67 percent C2H2 at 1/2 atmosphere, and 9 to 68 percent C2H2 at 1 atmosphere.

Jan 1, 1967

By Russell R. Trengove

The Strawberry tungsten mine is in the Jackass Mining District, in an isolated portion of eastern Madera County, near the southeast corner of the Yosemite National Park. The deposit was discovered in 1941, and production started in 1943 when the mill was completed. With the exception of 1946 and 1947, production has been continuous. The area in the vicinity of the mine is granite containing islands of sedimentary beds highly altered by metamorphism that resulted from the intrusion of acid igneous rock. Schoelite occurs in almost vertical lenses of tactite between the limestone and the granite.

Jan 1, 1949

By Martin H. Rogoff

The presence of antibiotic materials extractable with polar organic solvents was demonstrated in coals of various ranks. Since these antibiotics occur in low concentrations, 200 pounds of a high-volatile C coal was extracted with acetone at room temperature to obtain sufficient material for detailed study. The biologically active materials in the extract were concentrated by extracting with aqueous sodium hydroxide. The fractions soluble in sodium hydroxide inhibited bacterial cultures when present in concentrations comparable to those at which other antibiotics are active (5 µg/ml). Steam distillation of the extracts did not yield highly active materials, contrary to the finds of other investigators. Mass spectrometry of the extract indicated, mainly, the presence of 6-ring compounds in the region of mass 324 to 392. The predominance of 3-ring aromatic systems found by ultraviolet analysis suggests compounds such as biphenanthryl or similar structures. The activity of the hydroxide- soluble material decreased markedly when the phenolic hydroxyl groups were transformed into trimethylsilyl ethers. Hydrolysis of the ethers yielded a product having the same activity as the original material, which indicates that phenolic compounds are largely responsible for the antibiotic activity observed.

Jan 1, 1963

By Richard J. Mainiero, Eric S. Weiss

This project investigates the behavior of blast waves from the detonation of high explosives in an underground mine. A series of explosive tests was conducted in the underground and surface facilities at the Bureau of Mines&apos; Lake Lynn Laboratory to evaluate the potentially dangerous effects of blast waves produced by open shooting, blown out holes, or accidental detonations of explosives. Shots of C4 and TNT were fired at the dead end of a 6 ft high by 20 ft wide entry, at the intersection of two entries, and on the surface. C4 and TNT were chosen for this research because they exhibit very consistent performance. Behavior of the blast wave was evaluated through recording of the pressure as a function of distance from the explosive detonation. For both explosives, C4 and TNT, peak pressure decay with travel down the entry was inversely proportional to distance to the 0.9 power. When comparing pressure measurements at 200 versus 100 feet from the detonation; at 200 feet the pressure would be 1/2 0.9 or 54 percent of that measured at 100 feet. By comparison, peak pressure for a surface shot exhibits a decay with distance to the -1.6 power, yielding a pressure at 200 feet 1/2 16 or 33 percent of that measured at 100 feet. This result confirms that the blast wave from detonation of an explosive in an underground mine maintains its force for a greater distance than would be the case on the surface. Table and figures follow the text.

By Stuart Bjorklund

This paper is one of many reporting various aspects of the Bureau of Mines program initiated in August 1939 by passage of the Strategic Minerals Act J the scope of which was greatly expanded by subsequent legislation. In its program of investigation 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. The occurrence of chromite in the Knik Valley near Palmer, Alaska, was brought to the attention of the Bureau of Mines in September 1941 by George Johnson, of Anchorage. At that time a preliminary investigation was made by Robert S. Sanford, an engineer of the Bureau of Mines. The area was investigated on June 4 and 5, 1943, by Henry R. Joesting and Leo H. Saarela, engineers of the Territorial Department of Mines. In August 1942, a second chromite occurrence, the Highway deposit, in the Knik Valley, was reported to the Territorial Department of Mines by John E. Ryan of Anchorage.

Jan 1, 1948