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By Forest J. Sur

"INTRODUCTION This report describes an exploratory project conducted by the Bureaus of Mines on a fluorite deposit, near Glenwood, N. Mex. Results of wagon drilling, crosscutting, and test pitting are given, together with results of metallurgical tests made upon samples of the ore. Mining and treatment methods are suggested.C. H. Johnson, Bureau of Mines engineer, examined the deposit in August 1942. H. E. Rothrock, of the Federal Geological Survey, completed a preliminary geologic study and mapped the deposit during the fall of 1942. As a result of these brief investigations, it was concluded that the deposit contained substantial inferred ore reserves, and exploratory work was recommended. G. A. ApelI, also of the Bureau of Mines, made a topographic and underground survey and report on the mine in March and April 1944. A wagon drill, air compressor, and other equipment and supplies were delivered to the property on May 19 to 23, 1944. Drilling began under the direction of the author on May 25, 1944, and was completed in October 1944. The results of drilling and. sampling form the basis of this report."

Apr 1, 1947

1. The following recommendations should apply to all mines, tunnels and underground quarries, but to opencast quarries only in so far as persons can be exposed to dust injurious to health. General In the present state of knowledge, all duets liberated in mining, tunneling and quarrying operations should be considered potentially injurious to health if breathed in sufficient quantity; dusts containing free silica should be considered specially injurious to health, the injurious particles being below 7 microns in diameter.

Jan 1, 1954

By Howard E. Parkinson

In 1969, new coal mine health and safety legislation was enacted in the United States. As a result of this legislation, the Department of Interior, Bureau of Mines has carried out communications research aimed at developing whole mine communications for increased safety and efficient operation. The research has advanced and many promising results are now being demonstrated to the mining industry. However, there remains a challenge to further improve wireless communications within the mine workings, and through the overburden above the workings. The objectives for future research and development will be discussed, together with the physical and operational constraints that new mine communication systems must face.

Jan 1, 1973

By Frank E. Cash, Max S. Peterson

"INTRODUCTION Falls of ground cause the greatest number of accidents at underground metal mines. Statistics compiled by the Federal Bureau of Mines show that during a 13 - year period ended in 1943, falls of ground caused 35 percent of the fatalities and 16.8 percent of the nonfatal injuries at underground metal mines in the United States. 4/ Expressed on a basis of a million man-hours worked, the frequency rate was 0.355 for fatalities and 11.76 for nonfatal injuries. Although some progress has boon made in preventing rock-fall accidents over a 30- or 40-year period, the problem is still a major one requiring the diligent efforts of management and employees.In the Lake Superior district: where organized safety programs have been in effect for more than 30 years, the record is more favorable. Statistics compiled by the Lake Superior Mining Section of the National Safety Council reveal that over a 6-year period ended in 1945 the frequency rate of fatalities per million man-hours was 0.277, and the rate for nonfatal injuries was 2.38 from falls of ground.Although the above-given statistics do not cover equal or concurrent periods, the improvement in accident experience in the Lake Superior district over the national average, is obvious. This improvement is due to more effective methods of ground support or more rigid enforcement of the use of known methods.It is hoped that the following information about ground-support practices in the Lake Superior district will assist operators of other mines in their efforts to reduce accidents from falls of ground."

May 1, 1948

By F. D. Everett

Thermoelectric and metal alloying applications have changed the status of tellurium from oversupply to under supply . In a search for new sources of this element in Arizona , Colorado , New Mexico , Utah , and neighboring states , the Bureau of Mines analyzed more than 200 samples and obtained the results of tellurium determinations by private companies on more than 500 samples from a wide variety of mineral - bearing deposits . The About 40 minerals containing tellurium have been reported , mainly tellu- rides of gold , silver , bismuth , mercury , lead , copper , iron , and nickel . minerals usually occur in small quantities and identification in ores is extremely difficult . Samples containing more than 0.1 percent tellurium were taken from the Hilltop and Memphis properties in Dona Ana County , N. Mex . , and the Silver King property in White Pine County , Nev . , where development was chiefly for base metals . The Lone Pine mine in Catron County , N. Mex . , and the Bambolla mine near Moctezuma , Sonora , Mexico are potential sources of native tellurium occurring in small but high- grade pods . Much of the production of tellurium has come as a byproduct of electro- lytic refining of copper and lead- zinc ores in Arizona , Colorado , New Mexico , and Utah . Base -metal ore deposits will continue to be the most important pri- mary source of tellurium , although the concentration in ores is nearly always less than 10 parts per million . Any significant increase in output of tellu- rium probably will be related to production and improved efficiency in smelt- ing and refining base - metal ores .

Jan 1, 1964

By S. M. Shelton, J. B. Zadea, M. M. Fine, T. L. Johnston

"INTRODUCTION The Mayfield manganese property is about 25 miles south of Van Horn, in Jeff Davis County, Tex. The ore deposit is developed by a large open-cut and a small stope.An 8-ton sample was received for testing; it was taker at random from material on the mine dumps and consisted of a mixture of manganese oxides, barite, and siliceous gangue minerals. The manganese occurred largely as hard, massive, crystalline psilomelane, with a small amount of pyrolusite. The gangue minerals consisted of intermixed iron-stained sand stone, quartzite, chalcedony, calcite, quartz, and barite. Chemical analysis showed 8.9 percent manganese, 3.3 percent iron, 38.4 percent silica, 6.6 percent calcium carbonate, 7.1 percent barium, 3.1 percent alumina, 0.09 percent phosphorus 0.01 tungstic oxide, and less than 0.05 percentAnalysis of selected clean pieces of manganese minerals, free of gangue, showed 48.1 percent manganese end 13.4 percent barium, of which only 0.2 percent was present as barium sulfate. This indicated a limit in concentration. Barium was also present in the gangue as a separate mineral, barite (BaSO4), which has approximately the same specific gravity as the manganese oxide."

Apr 1, 1942

By R. L. Grant

Study of the ignition of firedamp by explosives and the phenomena that underlie it is one of the long-term investigations of the Bureau of Mines. This report is the third in e series by the Explosives Branch summarizing the progress made at Bruceton in this study. The first paper described preliminary work on small, carefully controlled cannon shots the second discussed the results of suspended shots.5/ In this paper, experiments are described and interpreted that extend and support the concept of ignition presented previously. ACKNOWLEDGMENT The authors wish to thank Bernard Lewis, former chief, Explosives and Physical Sciences Division, and Guenther von Elbe, former chief, Physical Sciences Branch, Explosives and Physical Sciences Division, for their guidance and constructive interest.

Jan 1, 1954

By W. G. Sandell, G. M. Potter

"As a part of the wartime activities of the Bureau of Mines, metallurgical services were extended to other Government agencies engaged in purchasing and stock-piling some of the more critical and strategic materirals. At the request of George A. Easley, representative of the MetalsReserve Company, beneficiation studies were made on a sample of complex tin-tungsten ore from the Urania mine in Bolivia, South America.The low-grade Urania ore (1.9 percent Sn and 1.55 percent W03) contained a very complex of cassiterite and scheelite with iron sulfidesand quartz. The problem involved in concentrating this ore was the removal of sulfides and silica by stage flotation and gravity concentration for the production of a marketable tin-tungsten concentrate. The sulfides and primary quartzite were readily rejected, but the secondary quartz was intimately associated with cassiterite, and ultimate recovery depended on treatment of minus 560-mesh (theoretical) sizes.The ore was amenable to concentration by ore dressing. Seventy percent of the tin and 83 percent of the tungsten were recovered in a product that assayed approximately 20 percent Sn and 20 percent W03 and that met grade ""F"" specifications of the Metals Reserve Company for mixed tin-tungston concentrates."

Feb 1, 1948

By T. Estelle Gardner, A. R. Taylor

Heat capacity measurements were made on sodium bromide ( NaBr ) and sodium iodide ( NaI) in the temperature ranges of 7 ° to 300 ° K and 56 ° to 300 ° K using an adiabatic calorimeter . Smooth values of heat capacity, entropy , enthalpy function , and free- energy function were calculated from the heat capacity data at 10° K intervals and at 273.15° and 298.15° K. Entropy and free energy of formation values at 298.15° K also were calculated for the two compounds using entropy values determined in this study and other data reported in the literature . The entropy values calculated at 298.15 ° K were 20.75 ± 0.06 entropy units (eu ) for sodium bromide and 23.55 ± 0.07 eu for sodium iodide .

Jan 1, 1964

By E. R. Palowitch

A centrifugal float-and-sink test procedure has been developed by the Bureau of Mines to reduce the time for the gravimetric separation of coals finer than l4-mesh from as long as 24 hours to less than 1 hour. Comparative tests indicated that centrifuging a minus 14-mesh Pittsburgh-bed coal for 20 minutes at 1,500 revolutions per minute produced results that compared favorably with static float-and-sink test results. Standard deviations of the mean recovery and ash content of the float obtained centrifugally ranged from 1.31 and 0.04 percent, respectively, at 1.30 specific gravity to 0.21 and 0.05 percent, respectively, at 1.60 specific gravity. As in static separations, retreatment of the products separated at low specific gravities was required.

Jan 1, 1961

By Richard A. Watson, James A. Powell

A seismic system which utilizes in-mine geophones to detect trapped miners has been developed. Tests at the Bureau of Mines Safety Research Mine at Bruceton, Pa., and at two operating mines indicate such a system has a maximum detection range in excess of 1,000 feet. The system is field worthy and portable and requires less than 30 minutes to set up and check. Real-time detection is possible.

Jan 1, 1976

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

By W. A. Dunkley

During the past year and a half the Western United Corporation of Aurora , Illinois , has been distributing carburetted water ges from its Lockport , Ill . , plant , to an extensive territory , under an initial pressure ranging up to 90 lb.. per sq. in . The most distant distributing point on the system is at Harvard , Ill . , about 35 miles from the plant.. The territory supplied is approximately 85 miles long and 35 miles wide , the total mileage of rains being 1223 , or approximately 24 per cent of all the gas trains in Illinois outside the city of Chicago .

Feb 1, 1923

By M. S. Seehra, R. S. Pandurangi

"INTRODUCTION Silica and kaolin (a layer aluminosilicate) are among the major constituents of most coal mine dusts.' Whereas kaolin is cytotoxic in vitro but nonfibrogenic in vivo in humans and experimental animals,2-4 the cytotoxic and fibrogenic potential of silica is rather well established.5 Wallace and co-workers 6-8 have studied the cytotoxic potentials of both native and surface-modified silica and kaolin and inferred that retoxification is slow in the case of occluded silica vis-à-vis native silica. Recent epide¬miological studies indicate that silica concentration alone in a mine dust, as determined by transmission IR spec¬troscopy (TIRS), does not correlate well with the pro¬gression of coal workers' pneumoconiosis. 9 This obser¬vation has led to the suggestions that silica particles occluded by clays such as kaolin may not be fibrogenic. This proposal requires accurate estimations of kaolin, silica, and occluded silica. The current method of silica analysis in a mine dust sample employs TIRS of the 797- cm -1 band of silica, although its accuracy, as well as that of x-ray diffraction studies, is no better than 25 % , even in a laboratory-generated dust.° In this paper we have employed the techniques of diffuse reflectance spectros¬copy (DRS) and photoacoustic spectroscopy (PAS), in conjunction with an FT-IR spectrometer, for the quan¬titative determination of silica in laboratory-generated silica-kaolin mixtures.One of the main advantages of DRS and PAS is that, in these techniques, problems arising from sample prep¬aration of the KBr-based disks used in TIRS are avoided. There are, however, several other considerations (e.g., particle size effects and saturation phenomenon) which complicate the use of DRS and PAS for quantitative work. 10-25 In this paper, we have carried out a systematic comparison of the quantitative abilities of the two tech¬niques, as applied to the silica-kaolin mixtures, with par¬ticular attention to the saturation behavior of several bands with different absorption coefficients. In particular, we show that a weaker band for silica at 1875 cm-1 is suitable for quantitative purposes, and that quantitative accuracy is higher in DRS than in PAS. Details of this work are given below."

Mar 1, 1992

By Heine Kenworthy

In 1930 the Shenandoah-Dives Mining Co. near Silverton, Colo., put into operation a newly erected, 300-ton selective flotation plant to mill complex ores from its nearby mine. The operation was a steady producer and was enlarged to treat 600 to 800 tons a day. In 1942 the company opened and started milling an area in the mine containing semioxidized ore. The valuable mineral. Content of this ore was considerably higher than in the straight sulfide ore previously handled alone. The mixture of clean sulfide and semi-oxidized ore was difficult to treat; consequently tailing losses, especially with respect to lead, were high. A. few years later, in order to study the possibilities, of obtaining higher recoveries by a modification of the mill flow sheet, a 1,200-pound sample of mill feed, taken over a period of several days by the company, was submitted to the Mississippi Valley Experiment Station for testing. Although this sample proved to contain more than twice as much lead as the average yearly mill feed, the same problem of recovering the oxidized values were present.

Jan 1, 1948

By Richard H. Spencer, Thomas E. Doerfler, Robert L. Lagace, James M. Dobbie, William S. Hawes

This report assesses the expected detectability, on the surface above mines, of electromagnetic signals produced in the frequency band of 630 to 3030 Hz by a rescue transmitter activated by miners trapped underground. This assessment is based on a statistical analysis of experimental signal and noise data taken at a representative sample of coal mine sites well distributed over the United States underground coal fields. Regression analyses are performed to characterize the signal transmission behavior of overburdens as a function of depth and frequency. The predicted signal behavior is then combined with experimentally based distributions of the background noise, and aural detection characteristics of signals in noise, to generate curves of the expected probability of detection for trapped miner signals versus overburden depth and operating frequency. The implications of these results, and associated recommendations, are presented regarding the detectability of trapped miners, sensitivity analyses and confirmatory tests, and operational utilization considerations for the trapped miners and the search and rescue team on the surface.

Jan 7, 1980

By I. AITKENS

The precious stones rubies and sapphires are transparent varieties of the mineral corundum . Essentially they are aluminum oxide , but the aluminum is often replaced. by small amounts of chromium , titanium , or iron . The chromium is said to give a red color , titanium a blue , and iron a yellow . True rubies range from rose to a somewhat purplish red and are sometimes termed " oriental rubies " to distinguish them from spinel rubies , stones of inferior hardness , density , and value . " Oriental rubies " are very rare , and the so-called " pigeon's blood" variety is the most valuable . Sapphires normally range in color from palest blue to deepest indigo , but actually all precious varieties of corundum of any other color than red are called sapphires . The most esteemed tint is like that of the blue cornflower . Colorless corundum of gem quality is called white sapphire ; the yellow variety is described either as yellow or as golden sapphire ; and the pale pink is classed as pink sapphire . The word " oriental " is also used as a prefix in naming varieties of corumdum of less popular colors . For instance , oriental emerald is used for green corundum, oriental topaz for yellow , and oriental amethyst for violet to purple varieties . The chief physical characteristics of rubies and sapphires are hardness , adamantine luster , and moderately high specific gravity ( 3.9 to 4.1) . Next to the diamond, corundum is the hardest of all minerals ; in fact , the sapphire is number 9 on Moh's scale , ranking between the topaz and the diamond. Rubies crystallize in 6-sided prisms terminated by flat faces and other varieties of corundum with twelve inclined faces , six above and six below , meeting in a girdle . Corundum is doubly refractive , with a direction of single refraction running parallel to the edge of the prism . The refractive indexes are very constant, the ordinary index ranging from 1.766 to 1.774 and the extraordinary index from 1.757 to 1.765. The double refraction always remains the same.

Aug 1, 1931

By Charles Vaught

The purpose of this study was to determine mine workers' state of fie-fighting preparedness and the technology being used to detect and respond to underground coal mine fires. To investigate this problem, 214 underground coal miners were interviewed by U.S. Bureau of Mines researchers. Frequency distributions of workers' responses are presented in this report, along with segments of narrative accounts, to profile miners' fire-fighting capabilities. The data indicated that much variability exists from mine to mine and that there are several important changes operators may undertake in order to make miners better prepared to deal with fire underground: select appropriate sensors, establish and test a warning and communication protocol, construct a system capable of delivering hundreds of gallons of water per minute for sustained periods, institute formal fire preparedness audits, develop case studies of events that occur at an operation to use as teaching and assessment tools, and provide structured practice that can be incorporated into fire drills.

Jan 1, 2010

By Richard L. Sanford

This report summarizes the results of the development of a Directory of Computer Programs Applicable to U.S. Mining Practices and Problems. The Directory includes a sampling of computer usage in operating and manufacturing companies, consulting firms, computer companies, research organizations, universities, and various U.S. government agencies. References to computer applications throughout the mining industry are presented as well as comments on the availability of programs to interested organizations or individuals.

Jan 1, 1977

By F. S. Crawford

This report deals with the effectiveness and economy of installing mine timbers treated with preservatives in long-life service locations. Early in the present century, when mine timbers and labor were plentiful, it was not general practice to install treated timbers in such places. Because national sources of good mine timber are declining steadily, the mining industry must now conserve timber. Moreover, the cost of installing and replacing mine timbers has been rising. Therefore, even the simplest of treatments can be expected to give some return on the investment when applied to timbers that are to be installed in relatively permanent locations. Better methods of treatment will produce better returns. In a service test of maple timbers treated by the hot-and cold-bath method and installed in main haulageways of the Athens mine of the Cleveland Cliffs Iron Co., Negaunee, Mich., zinc chloride-treated timbers had an average useful life of 13.3 years; borax-treated timbers, 11.2 years; and sodium fluoride-treated timbers, 7.7 years. Untreated timbers used as controls had an average useful life of 3.8 years.

Jan 1, 1950