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By Robert E. Wallhagen

The froth foam seal topping system is part of a system for remote sealing of mine passages using flyash transported pnuematically from the surface. Making the final 5 percent of the seal with a foamed-in-place fire retardant polyurethane reduces the required flyash volume by 50 percent and provides a more reliable seal. Foam components are held at the surface under proper conditions of temperature and pressure; then conveyed down the borehole through individual hoses and mixed at the bottom with a static mixer. The polyol component is pre-mixed with fluorocarbon-12 which, when released from system pressure in the mixer, boils and causes the foam to expand. Difficulties in handling this particular foam formulation are offset by a flame spread index well below the 25 level by ASTM E-162 normally required for under-ground applications. Isocyanate, polyol (TDI) and catalyst are conveyed to the downhole package by three separate lines. Five additional lines operate the valving and convey solvent so that the mixer and package lines can be flushed immediately after foaming. The eight-hose bundle is provided in segments of several lengths so that bore-hole depths can be matched. Cast-in-place plastic cylinders hold the bundle together and transfer the weight of the hose through a special quick-release clamp to the crane's wire rope. The downhole package and hose bundle are deployed using a specially designed winch and crane system capable of borehole deployment to 1500 feet.

Jan 1, 1977

By Arden D. Fugate

This work was conducted to determine a feasible process for converting siliceous fluoride offgases to a commercially usable product. The offgases were generated by pyrohydrolytic defluorination of low-grade fluorspar in a gas-fired rotary kiln, and fluorine was collected as a hydrofluoric-fluosilicic acid. A silicon-free fluoride solution for further processing was then produced by neutralizing the acidic scrubber solution with anhydrous ammonia, silicon being separated as orthosilicic acid. Ninety to ninety-nine percent of the fluorine originally present remained in solution as ammonium fluoride. Silicon was also separated from synthetic fluosilicic acids, having F-to-Si weight ratios ranging from 3.50 to 14.3. The solutions below a ratio of 4.06, the F-to-Si ratio of H2SiF6, containing dissolved silicon were desiliconized as completely as those containing less than the stoichiometric quantity of silicon. An electrolytic-grade cryolite was recovered from the ammonium fluoride solution by reacting with either sodium aluminate or alumina trihydrate and sodium hydroxide. A product containing 97 to 100 percent of the fluorine, represented by Na3A1F6, was recovered, and 94 to 99 percent of the theoretical yield was realized.

Jan 1, 1963

By J. H. Bilbrey

A recording thermobalance ,vas used to determine the rates of oxidation of mol-ten tin over the temperature range 550°-900° C. Oxidation rates were found to vary widely for a given temperature, as previously reported by other investigators. 1 X-ray diffraction data indicated that the probable cause of these variations was the development of preferred orientations in the crystals forming the oxide film. No reasons for the differences in degree of preferred orientation were discovered. For relating the weight of the oxide formed (w) to the time of oxidation (t) an equation of the form wn = kt was found to best represent the experimental data. INTRODUCTION In the course of conducting investigations on the feasibility of using selective oxidation techniques for the purification of various metals in the molten state it was soon discovered that data on the oxidation of molten metals and alloys were very scarce. In contrast to the many hundreds of publications on the oxidation of metals in the solid state there are relatively few articles on the rates of molten-metal oxidation. In view of this scarcity of data, it was decided to institute a series of investigations into the oxidation processes of molten nonferrous metals and alloys with the expectation that the information derived could be put to practical use in developing and improving refining processes based on selective oxidation. This report is the first of a series in which oxidation data for molten nonferrous metals and alloys are presented.

Jan 1, 1955

By Jack L. Henry

The Bureau of Mines conducted seven pioneering experiments in a 12-inch-diameter Kroll reduction reactor to examine the feasibility of coreducing the chlorides of Ti, AI, and V to produce a homogeneous titanium alloy sponge. The coreduction studies proceeded in a normal manner, and the yields of sponge were comparable with those of pure titanium sponge made in the same reactor. Vanadium concentration was very uniform throughout the sponge cake when VC14 in solution in TiCl4 was fed into the molten magnesium. More difficulty was encountered in feeding solid VCl2 and AIC13. Vanadium and aluminum concentration in the sponge was not uniform, and mechanical difficulties were experienced with the small-scale screw feeder. Although the sponge varied in composition from region to region, the ingots prepared from it were uniform in composition.

Jan 1, 1974

By Florence L. Feicht, H. H. Schrenk, Carlton E. Brown

This report describes the dropping - mercury electrode , its use in analysis , and the procedure of the Health Division of the Bureau of Mines in determining lead , cadmium , and zinc . The dropping - mercury electrode or polarograph is an electrolytic device , one electrode of which consists of mercury issuing in small drops from a capillary tube . Such electrodes have been in existence for more than 50 years, but they were not used for analytical purposes until about 1922.6/ Developments since have been rapid , especially in Czechoslovakia , Germany , Italy, and Japan and more recently in the United States . A recent bibliography / contains references to, 825 articles issued from 1903 through 1940. In 1939 Kolthoff and Lingane presented the first comprehensive critical review, in English , of the device and its use in analysis . They have recently issued a book on the same subject. Similar information also is included in a recent book10/ by Kolthoff and Laitinen . Much of the information in this and the two following sections on this device and its use in analysis was obtained from these three publications . The use of the dropping - mercury electrode in analysis is based upon the fact that the kind and amount of electro - reducible and electro - oxidizable constituents in solution can be determined from the current -voltage relationships revealed by this electrode or electrolytic device .

May 1, 1942

By J. A. Organiscak

The U.S. Bureau of Mines investigated the relationship of bituminous coal seam parameters and the amount of airborne respirable dust generated at longwalls. Dust and coal samples were obtained from 20 longwalls operating in geographically representative coalfields throughout the United States. Statistical analyses of coal seam parameters and airborne respirable dust measurements indicate a likely causal relationship between seam type and respirable dust. Low-ash, high-volatile coal seams were associated with higher airborne respirable dust levels. A negative linear correlation (significant at the 95-pct confidence level) was observed between the seam's ash content and airborne respirable dust, explaining up to 18 pct (R2 = 0.18) of headgate dust level variation and up to 15 pct of tailgate dust level variation. Volatile matter was found to have a positive linear correlation with tailgate dust level, explaining 16 pct of the variation. Further data examination indicates that these relationships with dust are most likely nonlinear, because of improved R2 values over the linear correlations. However, a notable portion of longwall dust production is influenced by other operational parameters, so additional research under more controlled conditions is needed to determine the seam's causative functions.

Jan 1, 2010

By S. M. Marshall

The investigations recorded in this bulletin were conducted by the Pacific Coke & Coal Co. in cooperation with the United States Bureau of Mines and the University of Washington. They cover one phase of a comprehensive investigation to determine whether coals from an extensive, undeveloped area of Pierce County, Wash., can be used in the manufacture of coke for the iron blast furnace. The completed investigation had three parts: (1) A geological survey of the coal property, (2) washing and crushing tests of the coals, and (3) coking and by-product tests. The geological survey, which was not conducted in cooperation with the Bureau of Mines and the University of Washington, included systematic tracing of the coal beds by test holes throughout the property, except some portions covered by an impenetrable layer of glacial drift. By this means all of the beds were correlated, their thickness and general character were determined, and tonnage estimates were made. Only such parts of the survey results as are necessary to a full explanation of the investigations described herein are included in this bulletin.

Jan 1, 1931

By Irving Hartmann, John Nagy, Donald Mitchell

"SUMMARY AND CONCLUSIONThe test data indicate that water infusion of the Pittsburgh coal seam does not reduce the amount of fine dust produced during mining operations to the extent reported elsewhere. Wide variations in the amounts of dust collected in the air current were noted in duplicate samples and repetitive tests. Changes in depth and location of the infusion holes and amount of water injected and addition of a wetting agent to the water had little effect on the amount of dust liberated.Water was forced readily into the coal. Some water flowed out along the cleats, but an appreciable amount remained in the seam. Little or no water pene¬trated the coal seam above the upper infusion holes.The average dust concentration (with and without infusion) in the return air, 40 feet outby the working face, was 25 million particles per cubic foot during undercutting, 20 million during drilling, 75 million during shot firing, and 20 million during hand loading. At the working face the average concentration was 3 to 6 times higher. The concentrations were measured at an airflow of 1,600 cubic feet per minute (c.f.m.) at the face.On the basis of this short investigation, no final conclusions can be made on the effectiveness of water infusion in reducing the amount of fine dust liberated during mining in the Pittsburgh coal seam. However, the data indicate that dust reduction resulting from infusion would be small.INTRODUCTIONThe production of fine coal dust is an inherent part of nearly every phase of mining. The use of large, high-speed continuous-mining machines and other mechanical equipment has increased dust production. In addition, in coal seams that have been subjected to high pressures for a long period, and particularly in dry and friable seams, some very fine dust is in the seam before mining. Much effort has been devoted to allaying and collecting at its source the fine coal dust released during mining. One of the comparatively recent techniques that has been developed for this purpose is infusion of water or other liquids into the coal seam. This method consists of injecting water under pressure into a coal seam to neutralize the fine dust released during mining. The water generally is introduced through bore holes in the face before undercutting."

Jul 1, 1957

By H. E. Powell

This Bureau of Mines study describes two processes for recovering zinc, copper, silver, and iron from the magnetic fraction of a waste generated by the primary smelting of zinc in horizontal retort distillation furnaces. The laboratory-scale procedures include reduction melting to produce a high-copper iron and matte smelting to produce a copper-silver-iron matte and metallic iron. Zinc is fumed in each process and recovered as the oxide. Direct reduction melting yields a metallic iron high in copper and a small rich matte from the sulfur contained in the waste. The products of the second process are a matte containing essentially all of the silver, about 80 pct of the copper and 37 pet of the iron, and an iron-copper alloy containing all of the remaining copper. Extraction with metallic lead or sodium sulfate recovers essentially all of the copper from the molten high-copper iron and yields an acceptable foundry iron.

Jan 1, 1973

By Donald W. Mitchell

Certification tests for urethane-foam systems and techniques for apply-ing foam safely in mines are described. Fire hazard from foam exists if flame propagates beyond the ignition source or penetrates the foam. Foam that passes the certification tests can be applied on stoppings, continuous sections of ribs of relatively wide passageways (with no foam on the roof), short sections of roof such as overcasts, roof cavities, and intersections (with no foam on the ribs), and between buntons on one wall of a shaft. Foam on the ribs and adjoining roof presents a fire hazard. Stoppings covered with foam passing the certification tests are resistant to penetration of heat, flame, and smoke than similar stopping without foam. Flame propagation can be arrested by water sprays. Spontaneous ignition of foam can be prevented.

Jan 1, 1966

By John Henderson

If you missed this year?s Texas State Holmes Safety Association meeting, you missed a great one. On January 23 & 24, 2009, we held the meeting that was rescheduled when Hurricane Ike threatened Corpus Christi in September 2008. Sixty-five persons from across the state attended the meeting held at the Holiday Inn Emerald Beach. The weather was 82 degrees, and the sky was clear and perfect for a safety meeting. Evaluations submitted by the attendees gave the presentations, the networking, and even the food top marks. There were eight councils represented; Big Country, Central Texas, Costal Bend, Heart of Texas, Hill Country, North Texas and North Central. Presentations included Workplace Examinations, Emergency Preparedness, Screen Safety, Contractor Responsibilities, Powered Haulage, Supervising for Safety, and Basic Inspections of Slings and Rigging. Mr. Edward Lopez, SC MSHA District Manager, gave the State of the District Address.

Feb 1, 2009

In 1991, the USBM (U. S. Bureau of Mines) evaluated the mineral resources of the 174,550-acre Bear Creek-Poker Peak area. Located 40 air miles east from Idaho Falls, ID, the study area is in the Caribou National Forest but is mostly administered by Targhee National Forest. USBM personnel mapped and sampled mines, prospects, and mineralized sites in and near the study area. Five types of mineral occurrences were identified in the study area: phosphate, limestone and travertine, placer gold, coal and uranium (the latter contained in the coal), and oil and gas. The study area has a high potential for oil and gas; evaluation of these commodities were beyond the scope of this study.

Jan 1, 1992

By C. R. Stephan, N. B. Greninger, J. R. Lipscomb

The U.S. Bureau of Mines and the U.S. Mine Safety and Health Administration (MSHA) are participating jointly in a research program to evaluate the strength characteristics and air-leakage resistance of various proposed seal designs for use in underground coal mines. The full-scale seals were constructed in the USBM's experimental mine at the Lake Lynn Laboratory, air-leakage tested, then subjected to pressure pulses of 20 psig or greater. bjected to pressure pulses of 20 psig or greater. In experiments prior to this study, seven seal designs using solid-concrete blocks were tested. Only the standard-type seal passed the explosion and air-leakage criteria. Tests also were performed on four seals constructed with low-density foam blocks. All four of these seal designs withstood the pressure pulse. In more recent studies, nine cementitious foam seal designs of varying thicknesses and densities were investigated. Six of the nine designs successfully survived the explosion overpressures. Six wood- block convergence seals also have been tested. The typical 3-ft-thick, wood-block seal design currently used in many coal mines did not maintain its integrity, in the absence of convergence forces, following the explosion test. Five modified wood-block seals successfully withstood the 20-psig pressure pulse. Based on these tests, three alternative seal construction materials, cementitious foam, low-density foam block, and wood, have been approved by MSHA for use in underground coal mines.

Jan 1, 1993

By G. M. Potter, J. B. Rosenbaum, Masami Hayashi

Most Japanese copper smelters are located in areas of concentrated industrial activity and high levels of atmospheric pollution. A review of unofficial sulfur dioxide emission control data from major Japanese smelters shows capture of 91 to 99.7 percent of the sulfur in the smelter feed. The bulk of Japanese smel ting capacity was constructed in the last 10 years. Six of the major sme lters use flash furnaces, and two use reverberatory furnaces. A prototype three-furnace continuous system is in use as a parallel train with reverberatory furnaces at one smelter. Most of the sulfur dioxide is manufactured into sulfuric acid. The remainder is captured by gas scrubbers that yield gypsum and sodium salts. Ready markets exist in Japan for the acid and other su lfur byproduc ts.

Jan 1, 1967

By D. S. Burgess

An investigation of the hazard of spillage of liquefied natural gas (LNG) onto water is described. About 2,000 gallons of LNG were consumed in various tests. The initial vaporization rate of LNG following spillage was found to be 0.037 lb/ft2 sec; when the spill was confined, this vaporization rate was moderated after about 20 seconds by the growth of an ice layer on the water surface; when the spill was unconfined, a coherent ice floe was not observed and the vaporization rate was essentially time independent. The maximum diameter (in feet) of the spreading LNG pool was found to be given by 6.25 Wo 1/3, where Wo is the weight of LNG in pounds, Downwind of a natural gas source, time-averaged methane concentrations were given in good approximation by standard air pollution equations. However, peak concentrations were as much as twentyfold higher than average, adding an additional factor to the assessment of hazard. The effect of layering by the cold vaporized natural gas was similar to the effect of a temperature inversion on normal gases in the atmosphere. Small-scale explosions were observed on pouring LNG onto a water surface; no single explanation seems pertinent to all of the incidents observed.

Jan 1, 1970

By W. E. Young

This study was made to present the mining methods and costs of a uranium mine typical of other mines in the highly productive Westwater Canyon member of the Morrison formation in New Mexico. Four mining methods have been used at the Section 23 mine: the retreat- room-and-pillar method, a sublevel-slicing method (also called top-slicing), the horizontal-cut-and-fill method, and a modification of the ring-drill method. The application of the methods at this mine and at other mines in the area should be of benefit to operators with similar problems. Ore bodies in the Section 23 mine are irregularly shaped and vary in size, in rock strength, in moisture content, and in uranium concentrations; different mining methods are required and mining costs are not constant. A 6-month period of operation at the Section 23 mine was analyzed and mining costs, not including amortization, depreciation, or Federal taxes, averaged about $6.80 per ton.

Jan 1, 1965

By W. E. Young

This study was made to present the mining methods and costs of a uranium mine typical of other mines in the highly productive Westwater Canyon member of the Morrison formation in New Mexico. Four mining methods have been used at the Section 23 mine: the retreat-room-and-pillar method, a sublevel-slicing method (also called top-slicing), the horizontal-cut-and-fill method, and a modification of the ring-drill method. The application of the methods at this mine and at other mines in the area should be of benefit to operators with similar problems. Ore bodies in the Section 23 mine are irregularly shaped and vary in size, in rock strength, in moisture content, and in uranium concentrations; different mining methods are required and mining costs are not constant. A 6-month period of operation at the Section 23 mine was analyzed and mining costs, not including amortization, depreciation, or Federal taxes, averaged about $6.80 per ton.

Jan 1, 1965

By Leonard Obert

This Bur of Mines investigation considers the deformational behavior (creep) of pillars made from three quasi-plastic rocks--salt, trona, and potash ore. The first phase of this study considers the design of a model pillar suitable for creep tests; in the second phase, six model pillars prepared from salt from two sources, from trona, and from potash ore. The pillars in each group were subjected to a different but constant axial stress, and the axial strain was measured for 1,000 hours.

Jan 1, 1965

By Ralph H. Whaite

The Bureau of Mines program for microfilming maps of abandoned mines in the Pennsylvania anthracite region is described. A catalog of the maps that have been microfilmed in the Eastern Middle anthracite field--the first area to be covered in the program--is presented. Additional catalogs will be published as significant mining areas are completed.

Jan 1, 1965

By Ralph H. Whaite

The Bureau of Mines program for microfilming maps of abandoned mines in the Pennsylvania anthracite region is described. A catalog of the maps that have been microfilmed in the Eastern Middle anthracite field--the first area to be covered in the program--is presented. Additional catalogs will be published as significant mining areas are completed.

Jan 1, 1965