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By J. R. Thoenen

[For several years the Bureau of Mines conducted tests on ground vibration t emanating from quarry blasting in an effort to determine an index of destruction for different types of structures. Results of these studies have been published in four Bureau of Mines Reports of Invitations as well as in several articles in the trade and technical press.5/ The first paper (3)6/ discussed the subject in general and gave results s of a few blasting records. Some tentative theories also were advanced. The second paper (4) discussed results s of records made from blasting in a number of quarries.]

Jan 1, 1940

The above referenced contract between Badger Manufacturing Corporation and the U. S Bureau of Mines was executed June 30, 1975, as a result of the request for proposals for innovative machine concepts. We selected the cutting machine category because of the obvious lack of technical progress in this field for many years: Phase I of the contract required blasting fragmentation tests to determine proper blasting patterns for use with the auger-type kerf cutting machine. Phase II required design concept development for a machine capable of cutting a circular void as an aid to blasting.

Jan 1, 1975

By Jesse J. Brown

Over 60 simple; were prepared and forwarded to Dr, S. Z. Toma, TPO, PMSRC as a result of this project. Included among these samples were various low temperature forms of silica. Samples of quartz, cristobalite, and tridymite with iron, manganese, and titanium impurities present were prepared. In addition, a long series of samples both wet ground and dry ground for times from 1/2 to 8 hours were prepared. Numerous miscellaneous samples were submitted which included kaolinite, calcite, muscovite, illite, montmorillonite, Ba3(P04)2, and YPO4 among others, in response to special requests from the TPO. The silica rich portion of selected binary (CA 203-Si02, In 203-Si02, Li20-Si02) Na20-Si02, PbO-Si02, SnO2-Si02, Sn02-Si02 BaGa204-SiO2 and SrGa204-Si02) and ternary systems (Na20-Ga203-Si02 and Li20-Ga203-Si02) was investigated to determine the effects of solid solubility on the stabilization of the high temperature forms of tridymite. In addition to the determination of the extent of these crystalline solubilities, observations were made. on the mechanism of the transformation of silicic acid to tridymite and the rate of the reaction in the presence of foreign ions,

Jan 1, 1973

By J. R. Thoenen

[For several years the Bureau of Mines has conducted tests on ground vibration emanating from quarry blasting in an effort to determine Fin index of destruction for different types of structures. Results of these studies have been published in four Bureau of Mines Reports of Investigations as well as in several articles in the trade and technical press.5/ The first paper (3)6/ discussed the subject in general and gave results s of a few blasting records. Some tentative theories also were advanced. The second paper (4) discussed results s of records made from blasting in a number of quarries.]

Jan 1, 1940

By John A. Richards

This paper is one of a series being published by the Bureau of Mines on mining methods and costs. It describes briefly the manner in which slusher hoists and scrapers are used in connection with clock-caving methods at the Emma Nevada mine of the Consolidated Coppermines Corporation, Kimberly, Nev. Kimberly is in the Robinson mining district, White Pine County, 7 miles west of Ely. The district is served by the Nevada Northern -Railroad, which branches from the main line of the Southern Pacific at Wells, Nev., 140 miles north, Paved U. S. Highway 50 from Salt Lake City, Utah, to Reno, Nev., passes through Ely. The altitude at the collar of the Emma Nevada shaft is 7117 feet. The surrounding hills are covered with a sparse growth of juniper, pinon, and mountain mahogany.

Jan 1, 1940

By D. A. Reynolds

THIS PAPER gives results of an investigation of the composition and carbonizing properties of coals from the Beckley bed, Caretta No. 5 mine, Susanna, McDowell County, and Glen Rogers No. 2 mine, Glen Rogers, Wyoming County, W. Va. The investigation included BM-AGA carbonization tests at. 800° and 900° C. and various chemical and physical tests designed to evaluate agglutinating, plastic, and expanding properties of coal. Both coals were of low-volatile bituminous rank, and each was blended with 70 and 80 percent high-volatile A coal from the Pittsburgh bed, Warden mine, Allegheny County, Pa. The Beckley bed was 39 to 58 inches thick at three points in the Caretta No. 5 mine, and the coal was 39 to 49 inches thick. The carbonizing sample contained 83.0 percent fixed carbon on the dry, mineral-matter-free basis. It contained 3.1 percent moisture, 15.8 percent volatile matter, 72.4 percent fixed carbon, 0.7 percent sulfur, and 8.7 percent ash, as carbonized. The ash softened at 2,680° F. The free-swelling index was 7;i, and the agglutinating value was 7.7. This sample fused weakly in the Gieseler plastometer; its blends with 70 and 80 percent Pittsburgh coal attained maximum fluidities of 830 and 600 dial divisions per minute, respectively. The single coal yielded 83.0 percent coke at 900° C. Yields of other carbonization products per ton of coal at 900° C. were: Gas, 9,950 cubic feet; tar, 3.5 gallons; light oil, 1.36 gallons; and ammonium sulfate, 16.3 pounds. Blending with Pittsburgh coal lowered the yield of coke and raised the yields of other products significantly. Caretta coal yielded strong, blocky coke at 900° C., 89 percent of which was plus-2-inch size. Strength indexes of 900° C. coke from 30:70 blends of Caretta No. 5 and Pittsburgh and of Pocahontas No. 3 and Pittsburgh coals were, respectively: 2-inch shatter, 68 and 53; 1%-inch shatter, 90 and 85; 1-inch tumbler, 50 and 53; and %-inch tumbler, 62 and 65. The specific gravity of the 900° C. gas from Caretta No. 5 coal was 0.272, and the heating values were 491 B. t. u. per cubic foot and 2,440 B. t. u. per pound of coal. The blends yielded much richer gas. Yields of tar acids and bases (0.09 and 0.04 gallon per ton, respectively) were within the normal ranges for low-volatile coals. Caretta No. 5 coal expanded 7.5 percent in the sole-heated oven at a charge density of 55.5 pounds per cubic foot. The blends containing 70 and 80 percent Pittsburgh coal contracted 4.8 and 7.5 percent, respectively.

Jan 1, 1953

By G. B. Clark

One portion of this project was to test a blast shield and to design some features for a novel tunneling method termed the Automated Drill and Blast System (ADBS). The ADBS tunneling concept was developed for the design of an excavation system of greater efficiency than conventional drill, blast, and muck (DBM) systems by minimizing the down time and approaching the non-cyclic efficiency of continuous tunneling by means of small charge blasting. Small charge blasting uses simultaneously detonated, small light charges (less than 200 grams per hole) in four to eight shallow (24 to 36 in. deep) holes usually in a line. Limitation of the total explosive per blast reduced air blast overpressure, fly rock velocity, vibration, and noise. Thus, shielded equipment can remain at the face and a tunnel shield permits support personnel to work outby the shield at all times. The ADBS equipment will be composed of five components: (1) a chassis, upon which is mounted automated mucking equipment, and a frame which carries (2) the hydraulic drill(s), (3) load/blast system(s), and (4) control cab(s). The blast shield may have its own mounting. Ventilation, horizontal, and vertical alignment controls are incorporated in the system. The blast sheild, which protects personnel outby the advance equipment from air blast overpressure, fly rock, and gases, was tested with full scale small charge blasting. A blast shield was designed, fabricated, and tested under conditions anticipated for a working model. The shield was designed to expand to fit the tunnel shape, to seal itself to the tunnel periphery, and to contain air blast, fly rock, and gaseous explosion products. In addition, the shield, which was lined on the inby side with rubber belting, reduced the blast noise level outby the shield to 113 dBA or less, which is very near permissible levels. The test results show conclusively that the shield concept is viable. Based partially on the shield tests, a blast resistant control cab was designed to be located on the equipment chassis inby the blast shield to protect operators during blasting, and to contain all the controls necessary for system operation and safety. The economics of tunnel driving using the ADBS were compared with those of DBM. Four rock types, which determine advance rate, and four cost categories were examined. The results of this analysis are as follows: 1. ADBS advance rate is faster because equipment remains at the face and operation procedes semi-continuously. 2. ADBS bit and explosive cost (which accounts for 4%o of the total advance cost) is higher than for DBM. 3. ADBS equipment cost, on a per foot basis, is lower than for DBM. 4. Due to a reduced labor force, ADBS labor cost is lower than for DBM. 5. Because of the overbreak reduction due to controlled blasting, ADBS tunnel support cost is lower than for DBM. 6. On a per foot basis, total ADBS advance cost is from 17% to 20% lower than for DBM, depending on tunnel diameter and rock type. The small charge method greatly reduces ground vibration, increases personnel safety by limiting excessive fracture, and decreases tunnel support requirements by reducing overbreak. The overall analysis, tests, and results to date show that the Automated Drill and Blast System may be developed into a viable tunnel excavation method. The method also may be adapted to use in the mining of ore. For some types of mining operations, the cyclic nature of conventional drill and blast methods may not be a disadvantage, either where the drilling and mucking may proceed simultaneously or where the operations are carried out in adjacent working faces. The proposed method would find application where continuous methods of excavation are desirable.

Jan 1, 1979

By J. H. Daniel

This report, summarizing the results of two studies sponsored by the Bureau of Mines, presents information on the types of mobile machines used in surface coal mines in the United States, and the amount of noise to which miners are exposed. Data consist of a calculated value of the probability of noise overexposure caused by specific equipment. These data are extrapolated to estimate the number of overexposed operators. Bulldozers were identified as the major contributors to noise overexposure, and the report presents results of a Bureau-funded program on the feasibility of providing retrofit noise control on bulldozers.

Jan 1, 1980

By Richard A. Allwes

This U.S. Bureau of Mines report presents the results of structural analyses and full-scale physical tests conducted on a steel-set arch and tri-set. The purpose of the analyses and tests was to evaluate the suitability of these structures for use in roof-fall prone areas. The arch canopy test and design procedures previously developed by the Bureau were utilized in this evaluation. Theoretical resistance functions were established for the steel-set arch and tri-set and were representative of the experimental behavior of the structures. The resistance functions were used to determine the energy absorption capacity of the structures and to predict their dynamic response to impact loading. The dynamic tests demonstrated that the arch canopy design procedure is appropriate for tri-sets and yields conservative designs for both steel-set arches and tri-sets. As a result of this work, it is recommended that these two structures may be considered for use in roof-fall prone areas and for rehabilitation work, provided the arch canopy design procedure is utilized for each application and the principles underlying the design procedure are understood.

Jan 1, 2010

By T. D. Hackett

Multislice mining methods were analyzed by the U.S. Bureau of Mines to determine their application to western United States thick coal seams; ground control, geology, and costs were considered. Multislice mining is used in widely varying seam conditions worldwide, including flat seams too thick to mine in a single pass, pitching thick seams, and seams containing a rock parting. Longwall multislice methods predominate, but room-and-pillar variants also exist. The initial use of the method in western seams is planned at a deep Colorado mine where a rock parting will be used to separate two slices mined by longwall. Ground control and spontaneous combustion are major hazards associated with multislice mining. A well-consolidated upper slice gob can reduce ground control problems and provide a seal against spontaneous combustion. Geologic analysis indicates that the consolidation of the gob depends on the composition of the upper slice roof, the presence of water, and sufficient overburden pressure. A geologically competent intermediate rock parting can also reduce ground control problems and seal against spontaneous combustion. To compete in western coal markets, the cost of multislice mining must be within the range of normal longwall costs. Analysis indicates that multislice operating costs should be within this range, and that multislice mining costs decrease as panel width increases. Relatively wide (600 to 800 ft) panels also provide increased coal recovery.

Jan 1, 1990

By R. O. Dannenberg

The Bureau of Mines conducted laboratory investigations with the objective of developing an alternative process for recovering cobalt and copper from complex sulfide concentrates. Processes currently used depend largely upon precipitation techniques to remove impurities and recover cobalt from sulfate liquors prepared by oxidative pressure leaching of the sulfide concentrates. The Bureau conducted bench-scale research on a process for treating cobaltite concentrates, comprising (1) oxidative pressure leaching, (2) jarosite precipitation followed by H202 oxidation and pH control to remove iron and arsenic, (3) copper solvent extraction with a mixed hydroxyoxime-amine extractant, (4) copper electrowinning from recirculating acidic strip liquor, (5) selective cobalt extraction from copper solvent extraction raffinate with a phosphinic acid extractant, and (6) electrowinning of cobalt from a recirculating weak acid strip liquor. Overall cobalt and copper recoveries were 91.7 and 84.1 pct, respectively. Electrowon products assayed 99.8 pct Co and 99.89 pct Cu.

Jan 1, 1987

This report is the 21st in a series summarizing research and technologic work on coal and related investigations by the Federal Bureau of Mines - the Chard of the series published on a calendar-year basis 2/ Subject publica¬tions of the Bureau during 1956 are cited, and pertinent Bureau work is described briefly. The most effective method of conserving our important coal reserves is through improved technology of production and utilization. Associated problems form the program of the Bureau.3 4 5 6/ Potential production is depend¬ent on a knowledge of the quantity and quality of the reserves, and the Bureau continues to contribute information on this subject. Many problems are being studied that relate to improvements in current production, including mining methods and health and safety measures. Preparation of mined coal is necessary for its most efficient utilization. Preparation by conventional methods is being studied, as well as the development or new methods. Fundamental studies on the structure and properties of coal are necessary to insure full advantage of the special qualities of different coals. Controlling factors in the efficient use of coal in combustion, carbonization, gasification, and direct and indirect hydrogenation of coal are being studied continuously, and new processes are being investigated. The many advances in all these fields are discussed.

Jan 1, 1959

By H. V. Makar

Laboratory tests were performed to obtain a quantitative description of the effectiveness of sodium sulfate (Na2SO4) for removing copper from molten iron and to determine the effectiveness of Na2SO4 on actual auto scrap. The tests were conducted on induction melted heats of iron averaging 0.58 and 1.50 percent initial copper and on cupola-melted auto scrap containing 0.45 percent initial copper. The Na2SO4 was added in powder form in amounts ranging from 2.9 to 43.8 percent of the weight of iron being treated. The data showed that copper removal for the various Na2SO4 treatments followed a similar trend, regardless of the iron composition that was tested. The equation Y = 1 - e-3.23x approximately reflects the relationship between copper removal and amount of Na2SO4 added, where Y is the fraction of copper removed and x is the ratio of the weight of Na2SO4 added to the weight of metal treated. Copper removals ranged from 3.3 to 74.5 percent and reductions down to less than 0.10 percent final copper were achieved in the auto scrap. Copper removals were generally accompanied by sulfur removal, and initial sulfur contents ranging from 0.10 to 0.20 percent were reduced to as low as 0.02 percent. High temperatures and long slag reaction times tended to induce copper and sulfur reversion from the slag, but, generally, the Na2SO4 treat¬ments were effective up to approximately 2,820° F with reaction times not exceeding 7 minutes.

Jan 1, 1968

By Khamis Y. Haramy

This Bureau of Mines paper describes the use of the borehole shear tester (BST) In mines. Assembly and procedure sections explain how the equipment is assembled and used properly. Schematics of the BST, limitations, test hole specifications, data recording and calculations are all explained briefly, and an example of the data collecting and calculations is given to assist understanding.

Jan 1, 1981

By Alan H. Goode

Glass wool meeting requirements for commercial use was made from glassy fractions of urban solid wastes by the Bureau of Mines. This research was a part of the Bureau's program to develop building products and other usable materials from reclaimed urban waste materials. Mixes of molten glass were fiberized into glass wool during laboratory studies by impingement of a jet of compressed air on a stream of the molten glass. The principal test variable studied was composition of the melt; this was varied by adding dolomite and alumina to obtain molten glass with the handling characteristics required for producing final wool products of the desired composition and physical characteristics. When no charge is made for the waste glass and approximately $75 per ton can be obtained for the wool product, an interest rate of return on investment after taxes of about 12 percent can be obtained. If a charge of $5 per ton is required for the waste glass, a selling price of about $78 per ton would be necessary to obtain a l2-percent-interest rate of return on investment after taxes.

Jan 1, 1972

By Edward A. Barrett

The ability to recognize visual cues commonly associated with roof and rib hazards is fundamental to the prevention of groundfall accidents. The perceptual skills that miners possess to visually search and assess hazardous ground conditions differ considerably. This U.S. Bureau of Mines report summarizes recent investigations on the use of stereoscopic (3-D) slides as a training aid for improving the ability of miners to recognize the various geologic and mining-induced irregularities that cause ground-falls. The feasibility of using 3-D slides for training and their effectiveness for representing roof and rib hazard conditions are discussed. Information is presented on equipment and procedures for creating a 3-D slide program that can be updated by mine trainers. Recommendations are made on selection of 3-D equipment and on the use of 3-D slides for training miners to recognize roof and rib hazards.

Jan 1, 1988

By Lloyd H. Banning

Crucible-smelting tests at the Northwest. Electrodevelopment Laboratory and a pilot-plant test on electric smelting of western phosphate rock for the Westvaco Chlorine Products by the Tennessee Valley Authority indicated that the small vanadium content of the rock is concentrated in the ferrophosphorus by-product of Phosphorus smelting. This research is concerned' mainly with recovering vanadium and phosphorus froth the ferrophosphorus produced from western phosphate rock. Exploratory tests were made of several methods of treating vanadiferous ferrophosphorus. Attempts to separate vanadium as a carbide dross by saturating molten ferrophosphorus with carbon were unsuccessful. Volatilization of phosphorus from ferrophosphorus was accomplished to some extent, both with and without addition of sulfur in several forms, but elimination of phosphorus was not complete. Brief testing in a small experimental converter on oxidation of vanadium and phosphorus; into a slag by blowing with air showed promise. A method that comprised fusing vanadiferous ferrophosphorus mixed with soda ash under oxidizing conditions gave encouraging results and was tested beyond the preliminary stage. A slag product of the fusion contained most of the phosphorus and vanadium as water-soluble sodium phosphate and. virtually water-insoluble sodium vanadate. After leaching the sodium phosphate froth the slag, the leach residue was reroasted with soda ash and salt. This roasted product was leached again with water to extract the vanadium.

Jan 1, 1951

By Marvin L. Whisman

This report describes the preparation of tritium-labeled organic compounds to be used by the Federal Bureau of Mines in studying the role of certain gasoline constituents in gum-forming mechanisms. The gasoline constituents that have been investigated boil within a range of approximately 90 to 230° C. and can be classified as paraffins. naphthenes, olefins, diolefins, monocyclic aromatics, polycyclic aromatics, and organic sulfur, nitrogen,: and oxygen compounds. The technique of Wilzbach has been applied to more than 50 samples. Purification techniques have been developed that accomplish rapid and effective purification as well as removal of labile tritium in a one-step operation. Data are presented to show the rate of exchange between tritium and hydrogen that can be expected for a variety of compounds common to a full-boiling-range gasoline. These values should be useful to other investigators using tracer programs involving tritium labeled compounds.

Jan 1, 1961

This report presents the results of a study of Kennecott Copper Corporation?s Chino leaching dump at Santa Rita, N. Mex. The stability studies described herein were performed on only one cross section of the leach dump, utilizing data obtained from drilling, sampling, and testing, which was limited in nature. The first part of the report contains a discussion of site geology and seismicity, pertinent information on the waste material disposal system and leaching method, a discussion of the waste embankment characteristics, a summary of the engineering analyses, and a bibliography. The second part (appendices) contains basic geologic and engineering data supporting the discussions in the first part.

Jan 1, 1974

By W. W. Weller

Thermodynamic values for scandium and its compounds are very sparse. This is evident upon examination of any of the commonly used compilations of thermodynamic data. For example, National Bureau of Standards Circular 5004 lists only four heat of formation values, two free energy of formation values, and four heat-capacity values for scandium compounds. The entropy of crystalline scandium is one of the most fundamental values that has been lacking. This Bureau of Mines paper reports heat-capacity data for scandium metal in the temperature range from 50° to 298° K., together with the entropy value at 298.15° K. derived from these data through application of the third law of thermodynamics.

Jan 1, 1962