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By D. J. Singleton

Erosion corrosion of 12 alloys in phosphoric acid waste water was studied by the Bureau of Mines. Tests were conducted on oblate spheroids or cylindrical specimens in 12-and 60-cm-diam ball mills by grinding phosphate rock in gypsum pond water with a starting pH of 1.6. For comparison, tests were conducted while grinding phosphate rock in plain water. Static corrosion tests in gypsum pond water also were conducted. For all alloys, the wear by erosion-corrosion (milling with gypsum pond water) was greater than the sum of erosion (milling with water) plus static corrosion. Erosion-corrosion wear was about 1,500 to 3,000 mpy for the alloyed white cast irons, 1,000 to 1,400 mpy for commercial steel ball material and type 316 stainless steel, and 600 to 900 mpy for nickel-base alloys and a high-manganese, nitrided stainless steel. Alloy costs per unit of phosphate rock 'processed favor a low-alloy, high-carbon steel or a high-manganese, nitrided stainless steel.

Jan 1, 1985

By Richard L. Unger

The U.S. Bureau of Mines has designed, fabricated, and tested a prototype track maintenance vehicle for underground coal mines. The vehicle uses a stiff rotating brush to clean the track so that a visual inspection is possible. It is also equipped to measure track gauge and cross-level. The objective of this report was to describe the track maintenance vehicle and detail the results of investigations into present underground track inspection procedures and cleaning technologies, which led to the development of the prototype. Recommendations are made concerning the integration of components of this prototype vehicle into current track cleaning and inspection systems used in underground mines.

Jan 1, 1984

By G. W. Birge, D. E. Wolfson, J. G. Walters

An investigation was conducted to determine the relationship between ASTM and Micum tumbler data and to develop equations that would enable the conversion of data from one test method for comparison with those determined by the other , and thereby facilitate the international exchange of data . Relative strengths of 18 commercially produced cokes were determined by ASTM and Micum tumblers and ASTM shatter test . Two of the samples were coke produced for foundry use , and two were produced in beehive ovens . The remaining 14 samples were produced for blast furnace consumption and had ASTM tumbler stabilities of 36 to 58. Statistical procedures were used to relate the three test methods and also to evaluate the effect of charge weights , top sizes of coke , and types of screens specified by the two standard tumbler procedures , square - hole wire mesh for the ASTM tumbler and punched round - hole for the Micum . A significant result was that the data obtained with like screens have a higher degree of correlation with a smaller standard deviation than data from the screens specified for each tumbler .

Jan 1, 1964

By H. F. MILLE, Charles A. Kumke

This paper describes mining operations at the Iron King mine of the Shattuck -Denn Mining Corp. in Yavapai County , Ariz . It is one of a series being prepared by the Mining Division of the Bureau of Mines on mining practices and methods in various mining districts of the United States . The mine and surface plant of the Iron King mine are situated in secs . 15 and 21 , T. 13 N. , R. 1 E. , about 20 miles by State highway 69 east by southeast from the city of Prescott and 1 mile southwest of the mining town of Humboldt on the Prescott -Mayer branch of the Atchison , Topeka & Santa Fe Railroad (fig . 1 ) . A l-mile truck haul brings the mill concentrates (lead and zinc ) to bins on a siding of this line at Humboldt ; the silver -gold bullion is handled separately . Some of the oldest residents in the vicinity of Prescott claim that the original location for the Iron King mine was made in 1880. The earliest recorded production was in 1906-1907 . During the first World War the mine produced fluxing ore for the Humboldt smelter . In 1936 the property was purchased under tax sale , and a mill (140-ton capacity ) was erected in 1938. The capacity of this mill was increased to 225 tons the following year , and a cyanide plant was added in 1940 to treat mill tailings . In 1942 the Shattuck -Denn Mining Corp. purchased the property . A new working shaft was sunk , mine development was speeded , and mill capacity was again increased . The predominating locally formation of this district is a pre -Cambrian schist known as Yavapai schist . The Iron King deposit , which carries gold, silver , lead , zinc , and copper , occurs as a series of lenses in a sheared zone of the pre -Cambrian schist . Down to the 600 -foot level the ore was mined and drawn by the shrinkage method . The cut -and -fill method was adopted for the lower levels . Waste rock for stope fill was provided by block-caving an area on the 600 level . Main haulage drifts were driven in the firm footwall , and crosscuts were driven across the mineralized zone at 100 -foot intervals . Grab samples taken from each car of every working place and channel samples cut every 5 feet in development work are considered sufficient for estimating ore reserves .

Jan 1, 1950

Improve the accuracy of commonly-used mine air velocity measurement techniques. Approach The Bureau of Mines, through a contract with Ketron, Inc., conducted a detailed study to establish appropriate, generalized correction factors for commonly-used air velocity measurement techniques. The techniques used were centerline readings, continuous traverse and split traverse vane anemometer readings, and smoke cloud readings (see Bureau of Mines Bulletion 589 for details on the proper use of these techniques). The various measurement techniques were used at different mine test sites to measure different air velocities. The data collected from the test sites were used in a statistical analysis which determined a generalized correction factor for each measurement technique. The correction factor multiplied by the measured velocity was used to provide the true velocity.

Jan 1, 1984

Determine the site specific flow behavior of leachants and groundwater during development, production, and restoration phases of an in situ leaching operation. Approach A computer program has been developed which simulates the hydrologic activity associated with in situ mining. Various user options enable modeling of many of the site specific geologic conditions and well field specifications that affect the hydrology of solution mining. How It Works In situ hydrology is modeled, using a closed-form solution to the three-dimensional, partial differential equation that describes changes in hydraulic head as a result of pumping from leachant Injection and recovery wells. Model capabilities include arbitrary well patterns and pumping schedules, partially penetrating well screens, directionally anisotropic permeability and natural groundwater flow, in either

Jan 1, 1981

By Kathleen Madland Kowalski

In recent years the issue of human stress response in emergency workers has begun to receive attention. This paper presents a rationale for considering human stress as a significant factor in the management of emergencies It discusses the concept of stress, Critical Incident Stress in emergency responders, and intro¬duces the Critical Incident Stress Debriefing (CISD) process. It is suggested that in a disaster, the CISD process can improve the effectiveness of response teams on site, their turnaround time on site, and post disaster time off the job. This paper, prepared by a US Bureau of Mines research psychologist, offers some ideas to the mining industry in general, mine rescue trainers and more universally, to those responsible for developing emergency management plans.

Aug 1, 1998

By Robert H. Essenhigh

A stirred reactor (SR) combustion system has been developed to gather information on the mechanisms of ignition and flame propagation of coal dust under conditions similar to those found in coal dust explosion flames. The prime scaling variable considered in this study is that of rapid particle heating (between 105 and 106°K/sec) which is accomplished by means of turbulent mixing during combustion. The SR combustors tested in this study have consisted basically of spheres hollowed in the centers of refractory housings. Coal and air mixtures have been injected into the spherical combustion chambers through a single jet, two opposed jets or four opposed jets. The diameters of the jets have ranged from 0.63 to 0.22 cm. The volumes of the combustion chambers have ranged from 1.0 to 0.2 liters. The reactors have been equipped with thermocouples embedded in the combustion chamber wall as well as a thermocouple located in the exhaust gas stream. In the latter versions of the SR, provisions were made for both solid sampling and gas sampling of the reactant stream exiting from the combustion chamber. Experiments have been carried out using pulverized bituminous coal. The coal has been reacted in an SR in mixtures of air and air/nitrogen. These experiments have provided information on the mode of ignition of the coal as well as yielding information on the kinetics of coal pyrolysis through the use of SR theory. Ash tests performed on the reacted samples collected from the SR indicated that the majority of the values of weight loss percentage were between 60 and 70 percent. The percentages of weight loss were relatively unaffected by changes in temperature which varied between 1100 and 1700°K and by changes in residence time which varied between 10 and 20 millisec. Volatile matter tests performed on the samples indicated that the volatile matter left in the char ranged from 3 to 20 percent of the original content. By assuming that all the mass loss was due solely to pyrolysis with no combustion occurring at the particle surface, Q-factors for each test have been calculated. The results of these calculations indicate an average value of Q equal to 1.88. This finding shows that the majority of mass loss can be attributed to pyrolysis. The fact that the extent of reaction varies only slightly over the range of test conditions has been examined in the context of the two component hypothesis of coal constitution. This approach leads to the conclusion that the reaction of the "easily evolved" component VMI is extremely rapid and that the majority of it is removed from the coal in times less than the residence time in the system. This means that the volatile residue remaining in the char can be considered to consist of component II, VMII. If the mass fraction of VMI = 0, then an activation energy of 18.0 kcal is obtained for the pyrolysis reaction. If the mass fraction is assumed to be 0.75, the activation energy increases to 31.2 kcal.

Jan 1, 1978

By R. A. Friedel, J. L. Shultz, A. G. Sharkey

The purpose of this investigation was to study the primary materials associated with the coal structure . Mass spectrometric techniques can be useful in studying the chemical structure of coal and various high- molecularweight materials derived from coal . Investigations of pyrolysis products and extracts of coal , and also whole coal , showed : 1. Aromatic hydrocarbons obtained by the vacuum pyrolysis of coal below 300 ° C possibly were sorbed material rather than decomposition products . 2 . 2 . Thirteen structural types having molecular weights from 78 to 400 were identified in pyridine extracts constituting one - quarter or more of the coal by weight . 3. Material extracted at room temperature with a methanol - benzene solvent and a vacuum pyrolysis condensate obtained at 450 ° C contain similar components . The extract and the condensate have approximately the same average molecular weights ( 200-300 ) . 4. Material extracted from coal at room temperature is altered even by mild thermal treatment . 5. Changes in various alkyl series occurring in thermally treated coal extracts can be followed quantitatively . 6. Similarities in the spectra of coal and graphite were indicated in an investigation using a mass spectrometer equipped with a spark source . Determinations on a coal - ash sample by this technique showed good agreement with data obtained by emission spectroscopy .

Jan 1, 1963

By Charles H. Atkinson, Robert T. Johansen

Tremendous volumes of petroleum ( crude oil and natural gas ) at present cannot be recovered economically . The feasibility of using nuclear explosions for production stimulation therefore has been investigated . Data from underground nuclear tests conducted by the Atomic Energy Commission were reviewed , and the physical effects were evaluated for stimulating petroleum production . Calculations of the effect on ultimate recovery of increasing reservoir temperature with nuclear explosives showed disappointingly small increases . Production increases caused by fracturing of massive low- permeability reservoirs appear technically and economically promising . Petroleum reservoirs that might be converted from submarginal to commercial production are being located and evaluated as to potential reserves and as a location for a field test .

Jan 1, 1964

By D. J. Stoops, H. Kato, M. D. Carver

The effects of impurity elements silicon , aluminum, copper , nitrogen , and manganese , at 50 to 300 ppm, on properties of the zirconium alloy Zircaloy 2 were investigated . Variations in microstructure , mechanical properties , and corrosion behavior in some inorganic acid and salt solutions were observed with variations in level of impurity element . Corrodents were solutions of sulfuric acid , phosphoric acid , copper chloride , and iron chloride . Silicon was found to modify annealed microstructures by spheroidizing and dispersion of secondphase material throughout grains . Silicon or manganese improved ultimate and yield strength of the alloy without loss in ductility . All five elements affected corrosion rates of the alloy , the effect being generally different for each element .

Jan 1, 1964

By Wing G. Agnew

The first six Reports of Investigations in this series , pertaining to the investigation of stemming at the Mount Weather Testing Adit, dealt with ( 1 ) the dust produced by blasting , ( 2) the effect of stemming upon gases generated by blasting , ( 3 ) the relative advantages and disadvantages of different types of stemming and no stemming when used with 60 - percent ammonia gelatin dynamite , (4) the length of stemming material through which a primer will fire and detonate a charge of dynamite , ( 5) comparison of dust and gases produced when blasting charges of dynamite in drill holes , bombs, and mud - cap shots , and ( 6 ) the relative advantages and disadvantages of different types of stemming and no stemming when used with 40 - percent ammonia gelatin dynamite .

Oct 1, 1943

By Brian L. Quick

Problem: The National Institute for Occupational Safety and Health's [NIOSH] National Occupational Research Agenda (DHHS Publication No. 96 115) reports that approximately 50% of miners will experience hearing loss by age 50, compared to only 9% of the general population. The present investigation examines three antecedents believed to be associated with miner's use of hearing protection. Method: A posttest delayed posttest control group field research design was employed to assess antecedents toward wearing hearing protection. Results: Following the initial posttest, miners' attitudes and subjective norms were antecedents to intentions to wear hearing protection devices. Also, intentions toward wearing hearing protection predicted hearing protection behaviors. Approximately six weeks later, miners' attitudes and perceived behavioral control were each significant predictors of intentions to wear hearing protection and again, intentions were positively associated with hearing protection behaviors. Impact on Industry: Our results indicate that appeals to normative influences may be the most effective antecedent to employ when persuading coal miners to wear hearing protection. However, messages designed to impact attitudes and perceived behavioral control were also effective.

Jan 1, 2008

By Susan Brink

The U.S. Bureau of Mines is investigating the potential of in situ leach mining a variety of Cu, Mn, and Au-Ag ores. Geologic characterization of ore samples from laboratory leaching experiments is conducted both prior to and after leaching to assess the effects of leaching on the chemistry, mineralogy, and texture of the rocks. The identification and chemical compositions of ore, gangue, and reaction products are determined by a combination of techniques such as reflected and transmitted light microscopy, X-ray diffraction, electron diffraction, electron microprobe analysis, and backscattered electron imaging with scanning electron microscopy. The distribution of the desired metal in various mineral phases can be illustrated using elemental X-ray maps. The potential of reactive gangue minerals to rob Cu from leach solutions is investigated with the aid of transmission electron microscopy. Porosity and permeability are measured to determine how effectively the host rock can transmit leach solution. Textural relationships between ore, gangue, secondary reaction products, and fluid channelways are determined by petrographic examination and are documented by optical photomicrographs and secondary electron imaging. Representative sample selection is described, and several epoxy impregnation and sample mounting techniques are discussed.

Jan 1, 1991

By L. W. Kelly

The primary purpose of this paper is to show the appreciable savings that were made by roof-bolting the main west entry of the Kings mine, which was to be the permanent, main haulage road, as compared to the cost of supporting the same roof with peg timbering as first planned. Additional items that might prove valuable to other mine operators are contained in this paper and detailed below. 1. A detailed cost of the system of roof support known locally as the peg-timbering method is given. It consists fundamentally of supporting steel cross bars on pegs inserted into holes drilled in the ribs close to the roof. 2. A method of supporting the roof in caved entries is shown, where such support must endure for an extended period in haulageways and air courses.

Jan 1, 1952

By C. P. Fang, V. A. Marple, K. L. Rubow, P. H. McMurry

"It has been known for some time that sizes of aqueous particles may be affected by flow-induced relative humidity (RH) changes. The RH of air flowing through an impactor decreases as a result of pressure drop through the impactor and increases because of aerodynamic cooling within the high-speed jets, as illustrated in Figure 1. Because the sizes of aqueous particles depend on RH, the impaction stage on which such particles are collected may be different from the stage where they ought to be col¬lected, based on the particle size at the sampler inlet.Fuchs (1980) reviewed literature on water vapor condensation in impactors. The reviewed impactors operated at jet velocities of 100-250 m/s. Particle size increases ow¬ing to water vapor condensation were found in all cases. In one case (Khorguani et al., 1970), it was found that very small droplets (Dp <_ 0.02 um) containing sodium chloride and silver iodide were collected in an impactor with a cut point of 0.32 µm and a jet velocity of 100 m/s. Fuchs believed that such particles could not be captured in an impactor without having been enlarged by condensation. Winkler (1974) sampled at¬mospheric dust with a rectangular nozzle impactor that had a nozzle cross section of 0.3 x 15 mm, a cut size of 0.4 um, and an average jet velocity of 100 m/s. No adhesive was used on the impaction plate. The collection efficiency increased as air humidity was increased from 20% to 100%. The effect was especially noticeable in the increased collection efficiency for hygroscopic particles, and was attributed to condensation.Extensive theoretical and experimental research work on the distortion of the particle size distributions in impactors was done by Biswas and coworkers (1985, 1987). The impactors employed in the study were a low-pressure impactor with high jet velocity stages (Hering et al., 1978, 1979) and a conventional six-stage impactor, Sierra's model 226, operated in the incompressible regime. Ammonium sulfate aerosols were chosen for the study. In the low-pressure impactor, an orifice operating at a Mach number of 1 causes a sudden pressure drop, significantly reducing the RH in the next two stages (stages 5 and 6). This results in a 0.15-um diameter ammonium sulfate droplet shrinking to about 0.07 um at stage 5 when the inlet RH is 95%. In stage 7, the tempera¬ture drop is considerable because the jet speed is sonic. For an inlet RH of 95%, a 0.03 um droplet grows to about 0.06 um. However, the same size droplet at an inlet RH of 25% grows to only 0.04 um. For the Sierra model 226 cascade impactor that is operated with a Mach number of 0.27 at the last stage (stage VI), it was found that for an inlet RH of about 67%, particle growth would occur in stage VI. At 80% RH, both stages V and VI were affected. Biswas et al. (1987) stated that Mach number alone does not determine the size biasing; the type of aerosol, the inlet conditions, the temperature and pressure ratio, and the impactor geometry (throat length, jet-to-plate distance, etc.) must be considered for each stage in evaluating the distortion of the particle size distribution."

Mar 1, 1992

By Laurance L. Oden

The Bureau of Mines is developing melting data for binary combinations of the alkaline earth fluorides and yttria to facilitate the formulation of slag compositions. The present report deals with the SrF2-Y2O3 system for which liquidus and solidus temperatures and solid solubilities were determined. The information is presented as the phase diagram. The phase diagram was constructed from information obtained by ceramogra¬phy, X-ray diffraction, thermal analysis, and electron probe microanalysis of small specimens encapsulated in platinum-20 percent rhodium or molybdenum ampoules. The data indicate a simple eutectic system with limited terminal solid solubilities. The eutectic temperature is 1,457°±5° C, and the eutectic composition is 4±1 mole-pct Y203. Strontium fluoride containing up to 2 wt-pct 0 2 was studied to determine the effects of oxygen contamination. Oxygen levels in excess of 0.2 wt-pct resulted in eutectic formation between SrF2 and SrO. The eutectic composition is between 0.2 and 0.7 wt-pct 02, and the eutectic temperature is 1,447°±5° C. No intermediate oxyfluoride phases were detected.

Jan 1, 1974

By Robert D. O'Brien

"INTRODUCTION The Miscellaneous Minerals Division of the War Production Board requested the Bureau of Mines to investigate the Gallatin corundum property as a possible source of corundum, which was in short supply due to the war. The Gallatin corundum property, also known as the ""Fuller mine"", the ""Montana Corundum mine"", and as the ""Old Qorundum mine"" was first examined by a Bureau of Mines engineer 2/ in July 1943. Bureau of Mines work on the property started October 11, 1943, was recessed May 5, 1944, and was resumed in October 1944 when the diamond-drilling program started. The project was completed February 7, 1945. The data obtained are given in this report.The Federal Geological Survey made a reconnaissance survey in the spring of 1943 and mapped the area the following autumn. The results of these surveys are contained in a memorandum report prepared in December 1943.ACKNOWLEDGMENTSIn its program of investigation of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual investigative work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples and performs beneficiation tests."

Aug 1, 1947

By J. L. Reuss

The Bureau of Mines derived information on the softening characteristics of both unfired and indurated iron ore pellets as measured by hot compression strength in a laboratory study. A surprisingly high hot strength (240 1b per ½ -inch spheroid) was developed by unfired magnetite pellets near 900° C; lesser maxima were developed by pellets made from hematite and specularite concentrates near 1,000° C. Those from goethite remained weak throughout the pre induration heating. Fully indurated commercial pellets retain a high resistance to softening when heated in air. On the contrary, in a hot reduing atmosphere their high cold crushing strength dissipates rapidly. At 1,000° C, for example, the average compression strength of seven different commercial pellets was 110 lb; at 1,100° C, the hot strength was only 60 lb. After a rather sharp initial drop, the loss of strength with increase of temperature was gradual. There was no sudden collapse, nor any significant difference, in behavior of commercial pellets whether made from magnetite or hematite concentrates.

Jan 1, 1968

By Gilbert M. Farrior

Tests of resistance to molten metals , to oxidation at elevated temperatures , and to various chemical reagents were made for a series of compositions in the TiB₂ - CrB₂ subsystem . In reaction with molten metals , there was no noticeable difference in reaction of the various compositions in the ( Ti , Cr ) B₂ series . The oxidation tests were ( 1 ) a rising - temperature test in which the specimen temperature was increased 4° per minute to 1,200 ° C and ( 2 ) a constanttemperature test in which the specimen temperature was held constant at 1,000 ° C. Compositions near Tio.6 Cro.4 B2 had the best oxidation resistance . Ti。.6 The chromium- rich alloys showed marked superiority to the titanium- rich alloys in resistance to corrosion by the chemical agents investigated . The chemical reagents used were sulfuric , nitric , and hydrochloric acids and sodium hydroxide of different concentrations .

Jan 1, 1964