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By Lawrence W. Scott

The performance of RETIMET metal foam as a flame arrester on explosion-proof enclosures was investigated by the U.S. Bureau of Mines both in laboratory tests and at the U.S. Mine Safety and Health Administration's (MSHA's) Approval and Certification Center, Triadelphia, WV. The objective of this research was to develop a permissible pressure vent for use on lightweight, vented, explosion-proof enclosures. In laboratory tests, four grades of RETIMET, a stainless steel foam material, were evaluated: (1) 45 NC-7, (2) 45 NC-13, (3) 80 NC-7, and (4) 80 NC-13. Explosive gas mixtures were prepared by a dynamic flow system. Ignition was by a low-voltage arc. Each grade of RETIMET metal foam successfully arrested the flame front in all methane-air tests. To evaluate RETIMET metal foam on large, commercial size enclosures,a multi compartmented enclosure was designed and tested in MSHA's explosion gallery in Triadelphia, WV. Extensive explosion testing revealed that a minimum vent-area-to-enclosure-volume ratio of 11.33 in2/ft3 is required to keep internal pressure rises below 3 psig. The RETIMET metal foam functioned satisfactorily in all tests as evidenced by the absence of external ignitions.

Jan 1, 2010

By Gregory B. Beacher

Analyses have been performed on geotechnical properties of copper, uranium and phosphate (gypsum) tailings materials, with the intent of identifying typical measures of variability within and among sites, and of characterizing such variability for use in reliability modeling of tailings embankments. In all, data from approximately 41 sites were analysed. Fairly consistent results were obtained for within site variabilities. However no one probabilistic model was found to be applicable to all sites. The distributional forms for most of the data sets are regular, and tend toward Normality when spatial trends are removed. At many of the sites sufficient in situ data were available to allow estimates of vertical autocorrelation distances and measurement noise. Available data indicate that variability in pore pressures may have a more important effect than strength property variation. A major problem in interpreting available strength property data results from the unknown drainage conditions during testing.

Jan 1, 1983

By Joseph D. Davis

The term "fusain" was first adopted from the French by the American geologist J. J. Stevenson in 1911, according to Wheeler, (1),3 who applies it to that portion of coal resembling charcoal, which he treats as one of the four ingredients of banded bituminous coal. The term has since been adopted by American writers. The Germans use it with slightly different spelling - namely, fusit. It is the equivalent of "mother-of-coal" and "mineral charcoal" of the earlier British writers. The English word fusain is also applied to "a crayon of fine charcoal" and is derived from the Latin root fusus. OCCURRENCE OF FUSAIN IN COAL AND ITS RECOGNITION Fusain is fairly widely distributed in coals of all ranks in varying amounts. It is almost always present in very thin sheets between the bedding planes of the banded coal constituents and presents a jet-black silky appearance who n the coal is split away. As fusain has little cohesive power the coal splits readily along the planes where it occurs. Such fusain bands often attain appreciable thickness -- frequently 1/4 to 3/4 inch. -Beet (2) has reported a maximum thickness of 2 inches for fusain partings, and Sinnatt (3) has found it in the form of plates and lumps; one lump taken by him from the Peacock mine weighed 3-3/4 pounds. Bore (4) has found it in coal balls. Sinnatt (3) states that fusain occurs in two forms, "the first a hard compact variety occurring rather rarely, which can not be pulverized by pressure of the fingers the second type is the common substance" -- that is, a very friable, easily pulverized material. The writer has also found the two types of fusain in the same coal bed and has observed that the hard variety contained considerable calcium carbonate, which probably entered the material in situ by infiltration. Sinnatt further remarks that the layers of fusain (soft type) usually contain less moisture than the coal (or lose it more readily on exposure), and when exposed they quickly change to flocculent powder so that the fines of the coal as mined are likely to contain a major proportion of this substance.

Jan 1, 1929

Investigate and demonstrate the possible use of low-density (45-lb/ft3) foam concrete for sealing abandoned mine openings. Although foam concrete has been used in the construction and geotechnical industries for some decades, it has not previously been used in abandoned mint shaft reclamation. Approach A structurally engineered permanent mine seal for an abandoned coal mine shaft, using low-density foam concrete and other appropriate structural materials, was designed by the Bureau and installed at a field site, the No. 22 Shall in Logan County, West Virginia. The field work was conducted by a private contractor under the supervision of the West Virginia AML Section (WV AML). The No. 22 Shaft is situated immediately adjacent to a frequently traveled county road. A few feet away from the shaft is a branch of Pine Creek. On the other side of the road is a railroad line that serves an active mining operation located several miles away. The shaft measures 9.5 by 9 feet in cross section and is about 300 feet deep. It was used at one time as a dewatering shaft and still contains two large-diameter dewatering pipes with steel drive shafts inside them. Before the beginning of the reclamation, the shaft included a concrete cap a few inches thick, with a 4 - by 5-foot access opening covered by a steel grate. The interior of the shaft was quite humid, and considerable flow of water at the bottom of the shaft could clearly be heard from the surface. Methane tests were conducted that showed the shaft to be clear of this gas.

Jan 1, 1992

By John W. Frey

Although there are certain general uniform provisions in the laws ... of the several Provinces of Canada the differences are so great that it is considered advisable to present digests of separate mining laws rather than a digest of Canadian mining law as an entity . This analysis , accordingly , has been divided as follows : Nova Scotia , New Brunswick , Quebec , Ontario , British Columbia , and a group of Provinces under Dominion Law .

Sep 1, 1930

By W. W. Adams

"Accidents at coal mines in the United States in September 1926 resulted in the loss of 170 lives, according to information furnished to the Bureau of Mines, Department of Commerce, by State mine inspectors. Of this number 125 occurred at bituminous mines and 45 in the anthracite field. As the bituminous output of coal for September was 48,976,000 tons, and the production of anthracite was 8,444,000 tons, the fatalities reported represented a death rate of 2.55 per million tons for bituminous mines and 5.33 for anthracite mines. The industry as a whole showed a fatality rate of 2.6 per million tons of coal produced in September 1925 the rate for bituminous coal mines was 3.29; the anthracite mines were idle in September last year due to a strike.During the first nine months of the present year 1,759 men have been killed by accidents at the coal mines throughout the United States, resulting in a death rate, per million tons of coal produced, of 3.76 as compared with 3.95 for the same period in 1925. Reports for bituminous mines alone showed a nine-month fatality rate of 3.53 which was about the same as the corresponding rate from January to September in 1925. The anthracite rate for the present year, however, shows a decrease of about 17 per cent; that is, the rate has declined from 6.36 to 5.28.Records covering the first nine months of 1926 show that 12 ""major"" disasters, that is, disasters in which five or more men were killed at one time, have resulted in the loss of 271 lives as against 10 disasters and 199 deaths in the corresponding months in 1925. The fatality rates for these disaster: alone were 0.579 and 0.465, respectively. One major explosion occurred at Tahona, Oklahoma, on September 3, 1926, in which 16 men lost their lives.An analysis of the principal causes of the 1,759 fatalities for the first nine months of the present year shows a reduction in the death rate as a whole and for falls of roof and coal and for explosives, but an increase in haulage, gas and dust explosions, and electricity. The comparative rates for these accidents were:"

Oct 1, 1926

By W. W. Weller

Heat-capacity measurements of sodium dimolybdate (Na2Mo207) and sodium ditungstate (Na2W207) were conducted over the temperature range from 51° to 298° K. The entropies of the two compounds at 298.15° K were calculated from the heat-capacity values and were used, in conjunction with other entropy data, to evaluate the entropies of formation of the compounds from their constituent elements and oxides.

Jan 1, 1963

By THOMAS SOULE, R. I. C. Manning

The Phelps Dodge Corporation considers safety a major operating problem , both from the humanitarian standpoint , for this company has a real interest in the welfare of its employees , and from the economic standpoint , for it has found the safe way to be the most economical . In turn , a feeling among employees that the company really has their interests at heart has a wonderful psychological effect . It is bound to bring forth more and better work and to attract and keep workmen of the better class . There is keen competition between the various branches of this corporation for a trophy that is awarded each year to the one having the best accident record . This trophy was won by the Nacożari branch of the Moctezuma Copper Co. in Mexico in 1926 and 1927 , and the Morenci branch won the trophy in 1928 and 1929 .

Oct 1, 1930

By D. S. Kingery

Experiments initiated by the Bureau of Mines on August 26. 1969, and recent work of others, have demonstrated the effectiveness of ventilation for controlling concentrations of respirable coal mine dust. Substantial reductions in dust concentrations have been attained by increasing the volume and rate of air movement across the face and by controlling the airflow pattern. Ventilation experiments conducted by the Bureau using high-pressure fans as auxiliary ventilation units showed that lace-generated dust could he effectively controlled in five mines employing continuous mining machines. Additional data was obtained on industry installations in two mines using similar ventilation systems. By maintaining an airflow approaching 100 fpm across the entry, the experimental system reduced the concentration of respirable dust by factors as great as 6.4. In all mines where the system was used the face-generated dust concentrations were reduced to below 3 mg/m3. Total respirable dust in two cases was above the 3 mg/m value because of the dust content of the intake air. In some mines. depending upon the type of coal being mined and other dust control factors in use, it was possible to Obtain concentrations of less than 2 mg/m Although the technology for the application of the dust control system investigated is readily available, it is evident that additional engineering studies should he made in each mine where the system is to be applied.

Jan 1, 1969

By A. L. Engel

Included in the program of the Rare and Precious Metals Station, Metallurgical Division, Bureau of Mines at Reno, Nev., are investigations of treatment methods for ores representative of various mining districts throughout the country. The samples received for this work may come from areas only recently explored or from newly discovered ore deposits in older mining districts. The present investigation deals with a case of the latter type, the. ample having come from a section that has a past record of considerable precious. metals production. The application of current treatment methods to this type of ore seems to offer excellent possibilities of satisfactory economic results. Definite identification of the silver mineral in this ore asthe chloride cerargyrite, AgCl, adds considerable interest to, the investigation, as in many cases where silver occurs in comparatively small amounts in an ore it is not possible to identify the particular mineral carrying the silver or else it is contained in or combined with other more common minerals. Cerargyrite is the "horn silver" of the bananza period and is mentioned in many accounts of pioneer mining of high-grade ores The occurrence of this mineral in finely disseminated form it a low-grade ore is believed to be unusual. The sample investigated was obtained from the' Bullfrog District neat Beatty, southwest Nye County, Nevada. The ore contained 16.7 ounces of silver per ton of ore, 0.007 ounce gold, and 0.32 percent copper in a silicious gangue, with accessory minerals, including iron oxides and scorodite; the hydrous iron arsenate.

Jan 1, 1949

By S. J. Page, J. A. Organiscak

Airborne respirable dust surveys were conducted at six surface coal mines to investigate the effectiveness of dust control methods used on rotary rock drills and bulldozers. Dust controls commonly used on drills include a dry dust collection system, exhausting from a shrouded area around the collared hole, and an enclosed drill operator cab, filtering airborne dust from the cab. Bulldozers are also typically equipped with an enclosed operator cab as a dust control measure. Airborne respirable dust sampling was conducted near each equipment's source of generation and inside its enclosed cab. Silica analysis was performed on the dust samples to determine the percent silica content in the dust generated at the six mining operations. An additional eight- month follow-up of dust sampling was also conducted in the enclosed operator cabs of several rock drills and bulldozers. Data were analyzed for long-term variability of accepted control methods to abate dust and silica levels. The highwall rock drill was the major and most variable dust source as compared to the bulldozer, generating dust levels, on average, one order of magnitude higher than dust levels of the bulldozer. Four of the six drills surveyed had dust containment and capture problems at the shrouded drill table above the lple. Repairs or modifications to three of the drill dust collection systems were shown to reduce dust levels by more that 50% next to the shrouded drill table. The enclosed operator cabs provided more than 90% and more than 40% lower dust levels than at the dust source for the drill and bulldozer, respectively. Long-term sampling of several of these highwall drills and bulldozers showed that the dust levels in the drill cabs were frequently higher than 0.2 mg/m3 and more variable than in the bulldozers. The bulldozer dust levels were frequently below 0.2 mg/m). Future research should focus on improving some of the deficiencies present in the drill's primary dust collection system, and developing quality control methods to ensure the integrity of enclosed cab protection for equipment operators.

By Agnes Y. Lee

The Bureau of Mines has developed an effective hydrometallurgical method to recover high-purity Pb metal and elemental S from concentrates. This low-temperature process eliminates S gases and Pb emissions, in contrast to the current high-temperature smelting technology. The method consists of (1) oxidative leaching with H202, Pb02, and waste fluosilicic acid at 95° C to produce a solution of PbSiF6 and a residue containing elemental S, (2) electrowinning the PbSiF6 solution at 35° C to produce 99.99 pct Pb metal and H2SiF6, and (3) solvent extraction to recover S, leaving a residue containing Cu, Ag, and other metal values. Spent electrolyte was recycled repeatedly, with impurity buildup controlled by controlling the leach parameters.

Jan 1, 1986

By Joseph Grumer

In addition to nine powder and gaseous extinguishants of propagating Pittsburgh seam coal dust-air explosions earlier evaluated,6 10 other powders have similarly been evaluated under like conditions such that wall quenching of the coal dust-air flames was virtually absent and the dust concentration was temporally and spatially uniform to within about ±5 percent. None of the newly examined extinguishants was better than Purple-K (potassium bicarbonate); the 10 of this report are anhydrite (calcium sulfate), monobasic (4 types) and dibasic ammonium phosphate, natural and synthetic cryolite (sodium fluoalumi-nate), sodium sulfate, and tricalcium phosphate. Except for anhydrite, sodium sulfate, tricalcium phosphate, and the cryolites, these materials were about equally effective, when present in relatively low concentrations (weight-percent of the coal dust-extinguishant mixture). The maximum oxygen concentration for the extinguishment of otherwise uninhibited coal dust explosions and the influence of coal dust particle size and the volatile content of the coal were also explored. For the present, the choice of the inhibitor among the good ones evaluated is not as critical as the system to be used to deploy the extinguishant against a coal dust explosion.

Jan 1, 1973

By Jay F. Colinet

Longwall mining in lower seam heights may necessitate the use of single-drum shearers to overcome size constraints associated with standard double-drum shearers. To avoid the operational problem of clearance in the tailgate entry with one single-drum shearer, two single-drum machines can be operated on the same face, with each shearer responsible for mining a predefined portion of the face. However, utilization of two shearers on the same face necessitates the positioning of one shearer operator and a jacksetter in the return air of the upwind shearer, thus complicating respirable dust control on the longwall. In an effort to evaluate the unique dust control problems associated with this type of mining, the U.S. Bureau of Mines conducted dust surveys on two multiple-machine longwall operations. Sampling was done to quantify major sources of respirable dust and to identify potential solutions to problem areas. Sampling results indicate that the cutting sequences utilized on multiple-machine faces may have to be designed to minimize dust exposure, as opposed to optimizing productivity or facilitating operational requirements. Also, state-of-the-art dust control techniques typically found on double-drum shearer longwalls must be employed to help minimize the exposure of all face personnel to traditional dust sources.

Jan 1, 2010

By Frank E. Federspiel

In 1992, the Bureau of Mines conducted a mineral resource investigation of the 19,200-hectare Garfield Mountain study area in east central Idaho. The area had been proposed for Wilderness. Cretaceous-age quartzite and limestone conglomerates underlie the area's east half; thick travertine beds, as well as limestones, dolomites, sandstones, and volcanic tuffs occupy the west half. All the rocks have been faulted and folded as part of the Western Overthrust Belt. Two, enormous travertine deposits occur in the west end of the study area. The lower deposit, controlled by Faxe Kalk Inc., has at least 200 million m3 (cubic meters) of travertine resources. Most of their deposit is very bright with a high CaC03 content and a low insoluble residual percentage: thus it is suitable for use as a paper and paint filler. The upper deposit, owned by Idaho Travertine Corp., contains 100 million m3 of travertine resources; it is used for facing or dimension stone. Weathered travertine outcrops are buff to tan and locally vuggy. Bureau of Mines samples of' outcrops contained greater than 95% CaC03. Approximately 600 m3 of travertine have been quarried from the two deposits and used for facing stone. Four travertine quarries and two dozer cuts were examined. Faxe Kalk has 103 White Rock placer claims on the lower deposit; approximately one-half of the claims are within the study area. Idaho Travertine has the Limestone 1 and 2 placer claims on the upper deposit. A 4,647-m-deep oil and gas exploratory well was drilled on the east end of the study area without success.

Jan 1, 1993

This report describes the activities and publications of the Bureau of Mines Health and Safety Research and Testing Center, Pittsburgh, Pa., for the fiscal years 1960-65. It includes a discussion or work being conducted on roof control, dust explosions, ventilation, health, coal mine fire control, and electrical-mechanical testing, and an abstract of each paper published during the report period.

Jan 1, 1966

By G. L. Oldright, Virgil Miller

"ACKN0WLEDGMENTSThe data given in this paper were collected at the Bunker Hill smelter through the courtesy of Stanley A. Easton, the vice-president and general manager, Frank M. Smith, the smelter director, and with the assistance and cooperation of A. F. Beasley, the smelter superintendent, and his staff members.THE BLAST FURNACE AND PLANTThe general lay-out of the recently built (1917) Bunker Hill plant has been given in the technical press in articles that were cited in Report of Investigations 3088. In addition it may be noted that the description of an ideal smelter given by Riddell 5 a year later fits the Bunker Hill smelter very well, with some changes, such as the location of the stack, made necessary by topography. For purposes of this article on the blast furnace it may suffice to state that the plant is one of the ""side hill location"" type. The various successively lower benches may roughly be considered as made for (1) the stack, (2) Cottrells and bag houses, (3) Dwight and Lloyd sintering machines with the equipment or bins for handling or mixing the feed and storing the finished product, sinter, and (4) the blast furnace feed floor with a slightly rising gradient to the bottom of the bins for sinter, feed, and take. The lowest bench (5) might be considered that of the blast furnace tapping floor at which or at appropriately slightly lower elevations are located the units for softening, refining, and treating precious metals, and for casting and loading lead. A very careful study of grades was made in order to be able to handle the products easily. All units were left with at least one end open to permit expansion of the plant, it desired, and each unit was separated from the other, evidently so that the operators on one level would be annoyed as little as posssible with the products made on another."

Apr 1, 1931

By V. E. Edlund

As part of its efforts to devise new and improved methods for recovering lithium from unconventional resources , the Bureau of Mines investigated a lime -gypsum- roast , water- leach technique for processing lithiumenriched ( 0.01-0.68 pct Li ) clays . This report presents the results of a study of the technical feasibility of extracting lithium from raw material representative of clay beds associated with the McDermitt Caldera complex in Nevada and Oregon . prepared from water used Pellets suitable for bench-scale roasting studies were mixtures of minus 200 -mesh clay , limestone , and gypsum , with as the pelletizing agent . Roasting pelletized charges at 900 ° to 1,000° C temperatures for 1- to 4-h periods produced calcines that leached readily , yielding water - soluble lithium sulfate ( Li₂SO4 ) . A 5-3-3 ( weight ratio ) mix of clay , limestone , and gypsum produced calcines with the best leaching characteristics . More than 91 pct of the contained lithium was extracted from pelletized mix batches roasted in covered refractory boats . Lithium recovery decreased to about 87 pct when the mix was roasted under dynamic conditions in a gas - fired rotary furnace . A reaction mechanism was postulated which indicated that dilution and loss of SO2 and oxygen in the combustion exhaust adversely affected the leachability of the dynamically roasted calcine .

Jan 1, 1983

By G. D. Jermain

The Bureau of Mines investigated the Gypsum-Camel deposit on Iyoukeen Cove Chichagof Island, Southeastern Alaska, from April 21 to August 26, 1948, as A part of the United States Department of the Interior program for developing an Alaskan construction industry. As gypsum is one of the components necessary for the manufacture of cement and one of the raw materials for plaster and plaster-board products, it is desirable to locate and develop a readily accessible deposit of gypsum in Alaska. In 1928, B. D. Stewart of the Territorial Department of Mines surveyed the gypsum deposits at Iyoukeen Cove, and during the summer of 1946 George M. Flint, Jr., and Edward H. Cobb of the Federal Geological Survey examined and mapped the old workings at Gypsum Creek and the prospect at Iyoukeen Cove. Both the Territorial Department of Mines and the Federal Geological Survey recommended the Gypsum-Camel prospect as warranting a diamond-drilling program by the Bureau of Mines. The Bureau of Mines project consisted of cleaning out and sampling, the old underground workings and diamond drilling from the surface to ascertain the lateral extensions of the deposit.

Jan 1, 1952

By R. J. Fantel

The Bureau of Mines investigated the resources, costs, capacities, market relationships, and short- and long-run supply of phosphate rock and phosphoric acid. The 206 mines and deposits evaluated in 30 market economy countries contain an estimated 35.1 billion mt of recoverable phosphate rock (demonstrated resource level). U.S. resources are sufficient to satisfy the domestic and export markets for phosphate products well beyond the year 2000. Because of resource depletion at current producers, however, new properties (with higher cost levels) need to be developed if U.S. production levels are to be maintained. Existing worldwide capacity can satisfy expected demand through the early 1990's. Expansion at existing mines or low demand growth could mean that no new property development will be needed before the late 1990's. Worldwide, almost $8 billion could be required for development of new phosphate rock properties between now and the year 2000, given 3-pct annual growth in demand. Most properties that could develop in the 1990's would require price increases of 20 to 50 pct to break even. To earn a 15-pct rate of return on investment, prices must rise to nearly double the present level of $24 to $29 per metric ton.

Jan 1, 1988