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By R. L. Grayson, T. Simonyi, R. A. Andrel

"The purpose or this paper is to disclose analytical, statistical, and observational results relating to mineralogy and trace elements in respirable dust samples collected from two different mines in West Virginia. Samples were taken from longwall panels, and the panels operated in different coal seams, one located in the northern part or the state and the other in the southern region. Mining conditions and equipment arrangements on the panels will be described along with dust control techniques used. Results from sample analyses are summarized with emphasis on relationships between mineralogy, trace elements and mineral particle size to worker locations. Correlations are made between micro x-ray diffraction and energy dispersive x-ray analyses for sample mineralogy.IntroductionThrough the work of many researchers worldwide, the health of coal miners in modern societies is now protected from harmful exposure to respirable coal mine dust. A vast amount of research culminated in the exposure-response model of Jacobsen, et al, (l) which has been used to establish the 2 mg/m3 exposure limit in the United States. According to the model exposure to respirable dust for 35 years at this level or less could prevent the occurrence of a clinically significant case of coal workers' pneumoconiosis (CWP) in a miner. The exposure limit, of course, must be adjusted whenever greather than five percent free silica exists in the respirable dust.The Jacobsen model was built around a mean mass concentration exposure, which generally showed the highest correlation with both incidence and progression of CWP. As Morgan, et al noted, however, the quantity of respirable dust inhaled is not the only significant factor. 2) They noted that although mass of respirable dust correlates highe.st with the incidence of CWP, it is not a causal factor. Admittedly, the insidious processes causing the disease occur at the lund cell-dust particle level."

Mar 1, 1989

By L. D. Wyant

[A convenient method for the, analysis of oil-wax mixtures has bean developed in the petroleum laboratory of the Bureau of Mines. This method has been found useful in studying the characteristics of the products obtained in petroleum refineries during the manufacture of ?wax distillate?, "foots oil", ?intermediate wax", and commercial paraffin. In this method ac-to-au is used as a selective solvent.]

Jan 1, 1924

By W. W. Adams, V. E. Wrenn

"Production of explosives in the United States during the calendar year 1936, as represented by reports of sales by manufacturing companies, totaled 391,604,500 pounds, an increase of 27 percent over the amount produced during 1935. This quantity included 81,698,375 pounds of black blasting powder (granular and pellet), 262,047,106 pounds of high explosives other than permissibles, and 47,859,019 pounds of permissible 5/ explosives.The manufacturers' reports to the Bureau of Mines classify the sales of explosives according to five main classes of work in connection with which the explosives were used.Coal mines used 87 percent of the total amount of black blasting powder sold, bituminous-coal mines 79 percent, and anthracite mines 8 percent; coal mines also consumed 98 percent of all permissible explosives and 9 percent of the high explosives other than permissibles. The coal-mining industry consumed 16 percent more explosives in 1936 than in the preceding year, the increase at bituminous mines being 21 percent and that at anthracite mines 4 percent.Metal mines used 29 percent of the high explosives other than permissibles and less than 1 percent of the black blasting powder and permissible explosives. The total quantity of the three classes of explosives used in metal mining in 1936 was 36 percent more than the quantity so used in 1935."

Jul 1, 1937

By J. T. McCartney

"INTRODUCTION The surface areas of the finest fractions of a pulverized material are disproportionately larger than their weights. For instance, Pesrott and Kinney 3/ showed that, in a sample of minus 200-mesh coal, particles that are about 2 microns in diameter represent 15 percent of the entire surface area but only 1.5 percent of the total weight. Because the sur- face area is the dominating factor in the behavior of finely divided materials in many practical processes, the role of the finest particles is of great importance. The oxidation and combustion of pulverized coal, both in the dry form and in suspension in oils, and the hydrogenation to fluid hydrocarbons of mixtures of pulverized coal and heavy oil are reactions in which the surface area of the coal particles has considerable influence. This investigation of the size distribution of fine coal particles was conducted with the hope that such processes would thereby be better understood. The results should also be of value in the study of the crushing and fracture of coal."

Sep 1, 1945

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

Jan 1, 1986

By H. C. Brunaugh, James Westfield, R. W. Whittaker

"INTRODUCTION The purpose of this circular is to describe the sealing off of a mine fire and subsequent use of carbon dioxide gas to extinguish it.A fire of electrical origin occurred in the Valier mine of the Valier Coal Co., Valier, Franklin County, I11., on March 29, 1949, at about 1:35 p.m. It was discovered about 3:35 p.m. in 5 south west intake airway inby 1 and 2 west panels. The No. 5 southwest airway had caved, and the fire was in the top coal beneath a large fall of rock. All men, except officials, were ordered from the mine. The mine officials decided to seal the fire, and four temporary seals were erected, which isolated approximately 200 feet of 5 south west entry. The seals were completed on March 30 at 2:45 a.m., but on March 31, at 3;40 a.m,, two of them were blown out by an explosion of gas that was produced by the fire. The two seals were rebuilt, the work being completed on March 31 at 12:00 noon, but they were blown out by another gas explosion at 12:10 a.m. on April 1. It was then decided to extinguish the fire with water if possible.To accomplish this, concrete-block dams were constructed. On April 1, about 4:25 a.m., when the dams were about half completed, water was introduced into the fire area through a 2-inch pipe.On April 4, J. G, Crawford, general manager of the Valier Coal Co., notified James Westfield, chief of the Vincennes (Ind.) Branch, U. S. Bureau of Mines, by telephone of the fire in Valier mine and requested assistance to combat it. Westfield, accompanied by F. J. Smith and H. C. Brumbaugh, Federal coal-mine inspectors, went underground and inspected the seals and dams. Later, during a conference with company officials, it was decided that the concrete-block dams were not strong enough to withstand the hydrostatic pressure that would be produced by flooding the fire area. It was then decided to use carbon dioxide gas to extinguish the fire. Four seals were completed, and 5 tons of carbon dioxide gas was introduced into the fire area, which extinguished the fire."

Apr 1, 1950

By H. Robert Ensminger

As a result of the new mining law implemented in August 1985 and the programs conducted by the Institute Ecustoriano de Mineria (INEMIN), which was created by this legislation, there was considerably greater activity in the nonfuels mineral sector during 1986. Over the next 2 years, INEMIN will be developing a national mining plan that will guide Ecuadorean mineral development for the balance of this century. As stage one of INEMIN's mineral study, historical records were reviewed and 300 abandoned mines and 1,200 unexplored mineral deposits were available for further investigation. In 1986, INEMIN established 5 branch offices and negotiated 250 new mining contracts with foreign companies valued at $16 million. Despite all this activity, INEMIN officials estimate that 100,000 square kilometers remain available for claim staking. Technical assistance contracts were signed with Belgium, the Federal Republic of Germany, Italy, Spain, and the United Kingdom, to assist in a variety of assignments ranging from helping prepare the national minion plan to the development of industrial mineral deposits.

Jan 1, 1988

By Stanton L. Tainter

"As an adjunct to its minerals-investigation program, the Bureau of Mines has developed a number of operating devices and techniques worthy of note. This paper, prepared under the supervision of J. H. Hedges, chief, Tucson Branch Mining Division, and under the general supervision of Lowell B. Moon, chief, Mining Division, reports upon certain methods devised to overcome difficulties encountered in cementing of diamond-drill holes at a Bureau of Mines project at Christmas, Gila County, Ariz.Pressure grouting was employed to recondition a caved hole it was desired to reopen and deepen. The hole, which had boon stopped 7 months previously at a depth of 488 feet, was caved below 449 feet in a contact zone of claylike, altered diorite and crumbly metamorphosed limestone. As other means of obtaining moderate pressure were not available, carbon dioxide gas, drawn from tank of liquid carbon dioxide through a pressure reducing and regulating valve, was used. The hole was reopened successfully with 12 grouting jobs.Another hole, where cawing from several water-bearing fractures between 202 and 232 feet gave trouble, was successfully cemented by the use of a grouting plug. An attempt to cement through the rods had failed, owing probably to agitation caused by water currents. Pressure grouting through the caning set above the cave could not be need, because water was forced up outside the casing when pressure was applied. The problem was solved by using a wooden plug 1-13/16 inches in diameter, which, when soaked in water, expanded to a tight fit in an AX hole. A hole was drilled through the plug, and a rubber flap valve was nailed to the lower end. In the upper end of the plug the hole was enlarged to fit loosely over an EX rod coupling finished smooth. The plug was lowered on the end of the drill rods to a point about 10 feet above the cave, where it was allowed to expand tightly to the hole. Cement grout was then pumped through the rods, and the rods were removed from the hole. After allowing time for the cement to set, the wooden plug was chopped out and drilling van resumed.Over 300 tests were made to determine the type of cement most suitable for use on the Christmas job, and the effect of cement-water ratio, temperature, and various admixtures on workability, setting time, and strength. The results of these tests, described in detail in the body of this report, indicate the desirability of thoroughly testing available cements when it is necessary to drill holes under difficult conditions that may cause failure.When it became desirable to reopen and deepen a caved drill hole, it was considered easiest to recondition the hole by pressure grouting, As other mans for obtaining moderate pressure were not available, a method utilizing carbon dioxide gas was employed. The hole was reconditioned successfully with 12 grouting jobs."

Nov 1, 1949

RI 9527. Effective Hazard Recognition Training Using a Latent-Image, Three-Dimensional Slide Simulation Exercise, by E.A. Barrett and K.M. Kowalski. Pittsburgh, PA: U.S. Department of the Interior, Bureau of Mines, 1995. NTIS stock number: PB95-170379. Rl 9531). Computer Modeling and Analysis of The Greens Creek Mine, Admiralty Island, AK, by MJ. Beus and T.J. Orr. Spokane. WA. -U.S. Department of the Interior, Bureau of Mines. 1995. NTIS stock number: PB95-176418. RI 9600. Application of Field Measurements and Computer Modeling to Evaluate Deep Mine Shaft Stability in Northern Idaho, by M, J. Beus, T. J. Orr and J. K Whyatt. Spokane, WA: U.S. Department of the Inferior. Bureau of Minus. 1996. NTIS stock number: PB96-140181. [ ]

Jan 1, 1995

By Thomas Varley

[For a year or more, statements have appeared in the technical press, and Especially in various trade journals, indicating that valuable metals such as gold, silver, platinum, and other rare metals, have been found and also have been successfully extracted from oil shales. These reports stated tat decarbonization and special methods of chlorination treatment, leaching and subsequent Precipitation, also cyanidation followed by table concentration of the residues after cyanidation, all indicated that told ad silver and other metals could be, and were, successfully recovered. Such articles have caused much misunderstanding, and as the correctness of some re of the statements made in them were questioned by some of the technical journals and by various chemists and metallurgists, an investigation of the subject. was begun by the metallurgical division of the Bureau of Mines, in order, if possible, to determine to what extent, if any, metals of value do occur in oil shales, and if so, the feasibility of attempting their recovery by tie processes said to have been used for teat Purpose. Inasmuch as the Bureau's station at Salt Lake City is investigating the recovery of oil from oil shales, the investigation of too recovery of metals from oil shales was assigned to my direction as superintendent 'of that station. An agreement had been entered into with the owner of m extensive oil shale deposit in Wyoming whereby I would personally collect the samples' of shales for use in the investigation.]

Jan 1, 1922

By L. Y. Sadler

The Bureau of Mines conducted a study Lo determine the loss in weight of silica (Si02) volatilization from low-alumina (A1203) refractories used as hot face liner materials in such process equipment as coal gasifiers, synthesis gas transfer lines, and ammonia plant secondary re-formers. Small specimens of 80-and 40-pct-A1203 brick and 95-pct-SiO2 brick were exposed to steam in high-pressure furnaces at pressures of up to 1,000 psig and temperatures up to 1,400° C for periods ranging up to 120 h. Weight losses from the 40-pct-A1203 brick after 40 h of exposure were highest, 2.75 pet at 1,400° C and 1,000 psig. The rate of weight loss had dropped to near zero after 80 h of exposure at all temperatures. No relationship between total silica content of the specimen and weight loss could be established nor did scanning electron microscopic examination of the specimens before and after exposure identify specific regions (e.g., surface) suffering a disproportionate share of the silica loss. It was concluded that minor silica volatilization is likely to occur, if at all, at temperatures of less than 1,000° C and pressures below 1,000 psig, and that low-alumina refractories should be used as dry-ash coal gasifier hot face linings.

Jan 1, 1986

By Russell R. Trengove

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

Jan 1, 1956

NIOSH recommends that exposures to respirable coal mine dust be limited to 1 mg/m3 as a TWA concentration for up to 10 hr/day during a 40-hr workweek, measured according to current MSHA methods (see Section 5.1 and Appendix J). NIOSH recommends that sampling be conducted with a device that operates in accordance with the NIOSH accuracy criteria [Busch 1977; Busch and Taylor 198 11 and the international definition of respirable dust [ACGIH 1994; CEN 1993; IS01993; Soderholm 1991a,b; 1989].* The REL represents the upper limit of exposure for each worker during each work shift. For single, full-shift samples used to determine noncompliance, NIOSH recommends that MSHA make no upward adjustment of the REL to account for measurement uncertainties [NIOSH 1994c] (see also Section 5.6.2). NIOSH further recommends that all reasonable efforts be made to reduce exposures to respirable coal mine dust below the REL through the use of engineering controls and work practices.

Jan 1, 1997

By Kenneth Lipman

Auxiliary equipment was assembled around a purchased oscillograph to permit observation of the current and voltage characteristics of low-energy, capacitance-discharge sparks having durations of at least 10 mµ-sec. Circuit details of the assembled apparatus, performance characteristics of the complete system, and some preliminary data from representative self-initiated sparks are given in this report. INTRODUCTION One of the subjects of continuing research by the Federal Bureau of Mines Division of Explosives Technology is the ignition of explosive-gas mixtures by means of low-energy capacitance sparks. Quite early in these investigations it was recognized that understanding the gas-ignition phenomena would be facilitated by detailed information about the performance of the ignition source (spark) under the actual conditions of interest; however, the sparks of practical interest are nonrepetitive transient phenomena whose duration could reasonably be estimated to be in the time range of 1 mµsec. to 1 µsec. As such, the only feasible method of obtaining detailed information was and is oscillographic representation of the pertinent current and voltage transients. It was not until 1947 that a suitable, commercial, dual-channel oscillograph could be obtained as the basic instrument for these studies; the instrument specified in 1947 was delivered in 1950. This paper describes the auxiliary

Jan 1, 1959

By Fredrick L. Johnson

No mineral resources were delineated during our investigation of the Antelope Wilderness Study Area (WSA). Only a few claims have been located in the area and only four workings were found. There has been, however, considerable exploration and mining activity in and near the south end of the study area. The Morey mining district, just southeast of the WSA, produced silver, and lesser amounts of gold and lead, sporadically from the mid-1860's through the mid-1960's. Long Lac Mineral Exploration (Texas), Inc. is actively exploring a large block of claims for hot-spring type, low-grade, large-tonnage gold deposits. Their claim block extends into the study area. The WSA, located midway between Tonopah and Eureka, encompasses approximately 87,400 acres. It is underlain by Tertiary rhyolitic and latitic volcanic rocks and by Paleozoic sedimentary rocks. At least three areas in the Paleozoic rocks have many of the favorable criterion for hot-spring type gold deposits; they have been faulted, silicified, brecciated, and hydrothermally altered, and have anomalous concentrations of precious metals and pathfinder elements. With additional exploration in the south part of the Antelope WSA, gold resources may be discovered.

Jan 1, 1986

By C. Stephan, E. Weiss, J. Trackemas, M. Sapko

The National Institute for Occupational Safety and Health (NIOSH), Pittsburgh Research Laboratory (PRL), in collaboration with the Mine Safety and Health Administration (MSHA), the mining industry and seal manufacturers, conducted a series of full-scale experiments within the underground experimental mine at PRL's Lake Lynn Laboratory. The purpose of the experiments was to evaluate the explosion-resistant characteristics of several new seal designs for rapid deployment during mine emergencies. These seals can be deployed in less than 12 hours and are capable of withstanding explosion overpressures in excess of 140 kPa (20psi). These novel seal designs use available mine materials, do not require conventional rib hitching and, most importantly, can substantially reduce exposure time for coal miners during sealing and mine recovery operations.

By J. J. Geraghty

U.S. Bureau of Mines researchers investigated the development of an innovative transport system for underground coal mining. A one-half commercial-scale bench model was constructed. Novel magnetic levitation (mag-lev) technology was developed. Frictionless and contact-free transport of a prototype materials container and payload has been demonstrated.

Jan 1, 2010

By John Zetterstrom

Increased activity in the beneficiation of taconite, particularly the magnetic variety, has shown the need for more information on the rate of oxidation of magnetite to hematite. This oxidation occurs in the pelletizing step of the beneficiation process. Magnetic taconite is an intimate association of magnetite and a siliceous gangue. It must be ground to approximately 70 to 30 percent minus 325 mesh to liberate the magnetite from the gangue. With sufficient liberation, magnetic concentration will yield a product high enough in iron and low enough in silica for blast-furnace use. The magnetic concentrate must be agglomerated before it can be used in a blast furnace. Agglomeration is the general term applied to all methods of compacting or consolidating fine iron-oxide materials, sintering and pelletizing being the two most common methods. Sintering is clone on a Dwight-Lloyd or Greenawalt sintering machine. Pelletizing consists of balling fine, moist oxide in a rotating drum, followed by baking at .a temperature below that of incipient fusion to develop a permanent bond within each pellet. The magnetic concentrate from taconite is too fine for good sintering practice but fine enough for good pelletizing practice.

Jan 1, 1950

By Ralph L. Brown

As a preliminary step in a recent study4 of the phenols present in a low-temperature tar, the writers prepared the hydroxyacetic derivatives of the simpler available members of the phenol series in order to obtain material to assist in fixing the identity of similar derivatives obtained from the phenols of the tar. When comparing the melting points of the pure derivatives we had made with those given in the literature we were unable to find the characteristics of one of the xylenol derivatives which we had prepared--namely the 1, 3 dimethyl-2-phenoxyacetic acid, In the belief that the compound does not appear in the literature we are presenting these notes on its preparation and its melting point. The hydroxyacetic derivatives are easily prepared and in good yield, and are useful in studying mixtures of phenols. The 1, 3 dimethyl-2-phenoxyacetic acid makes the fifth of the six isomeric derivatives to be reported in the literature. Gluud and Breuer report the preparation of the 1, 3, 4, the 1, 4, 2, and the 1, 2, 4 derivatives. A fourth isomer-¬the symmentrical 1, 3, 5--has been reported by Schutz6, although no record of it occurs in the indexes. The remaining derivative--the 1, 2, 8-has not, been found and it is now being synthesized in the Organic Chemistry Laboratory of the. Pittsburgh Experiment Station. It is true, however, that from a phenolic fraction boiling 215.9 to 2180 isolated from natural petroleum, Tanaka and Kobayashi7 obtained a hydroxyacetic derivative melting at 103.3°. They state that this is the 1, 2, dime ethyl-3-phenoxyacetic acid but present no evidence for the assertion. The known derivatives are summarized in Table 1 following;

Jan 1, 1929

By T. J. Ballard

Corundum is a natural alumina (A120 ) and is next to the diamond in hardness . Except for the gem varieties , it is used principally as an abrasive , chiefly in grinding , dressing , and polishing metals and optical glass . Natural corundum is preferred to artificial abrasives for certain specialized jobs . Most of the corundum ( excluding emery ) mined in the United States came from the Corundum Hill mine in North Carolina and the Laurel Creek mine in Georgia . The Corundum Hill mine provided over half of the domestic production of corundum prior to 1900. Since 1900 , the importation of foreign corundum and the manufacture of artificial abrasives caused the decline of corundum mining in the United States .

Mar 1, 1947