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By Scott W. Hazen, Richard F. Link, George S. Koch

The Mi Vida mine , Big Indian district , San Juan County , Utah , is in an ore deposit of uranium and vanadium minerals disseminated in certain sedimentary beds of the Triassic Chinle formation . Statistical analysis of assays of samples taken from the ore body affords an estimate of the grade of the ore body and provides a prediction about the direction of best mineralization beyond the sampled area . The basic data analyzed are assay results for uranium ( Uз Og ) , vanadium (V₂O ) , and lime (CaO ) from 225 channel samples cut at 79 sample points . Through the use of appropriate statistical methods , particularly regression analysis , the grade of ore may be estimated more precisely than by conventional means , and the most favorable direction to extend the mine may be predicted . Frequency distributions of assay residuals for uranium , vanadium , and lime are compared to frequency distributions of assays without regard to trend . Correlations among these variables are obtained and interpreted . The statistical methods employed illustrate certain techniques that may be used to analyze assay data from ore deposits in general .

Jan 1, 1964

By Mulligan John J.

The Bureau of Mines investigated lode tin deposits on Potato Mountain, Seward Peninsula, Alaska. Tin was found to occur as cassiterite associated with quartz, tourmaline, pyrite, arsenopyrite, and earthy clays, but the deposits lack the varied accessory minerals commonly found in tin districts. The tin-bearing deposits are in metasediments along minor breaks and bedding planes but not in the crushed earthy filling of major faults. Cassiterite and sulfides occur with quartz in veins, both with and without earthy clays, and disseminated through tourmalinized wall rocks. The deposits are characterized by irregular segregations containing 1 to 10 percent tin within zones averaging not over 0.25 percent tin. The largest segregation exposed is on the summit of a low hill on the east-central slopes of Little Potato Mountain; most of the outcroppings are in an area trending east to west, roughly 10 to 30 feet wide and 300 feet long. Sample values ranged as high as 12 percent tin, but the average grade may be about 1 percent tin. The extreme irregularity of both grade and composition precludes a more exact determination. Similar concentrations are scattered for over 1,000 feet to the west and north, but these are smaller and lower in grade. Elsewhere on Potato Mountain, generally similar deposits occur as clusters of veinlets at widely separated points in the metasedimentary walls of major faults.

Jan 1, 1965

By David D. Walker

The purpose of the investigation was to describe and appraise tungsten deposits in Montana . The work supplements previous investigations made by Pattee ( 10 ) and Walker ( 17 ) in selected areas of the State . Scheelite deposits in tactite are the most numerous and most important economically , having accounted for nearly all of the State's tungsten production . Of the 64 deposits examined during the current study , 50 contained scheelite , 11 hubnerite , 2 wolframite , and 1 ferberite . The State's major tungsten production has been from scheelite deposits in Beaverhead County . The report lists , by counties , the type and grade of each deposit . The more important occurrences are accompanied by geological and assay maps .

Jan 1, 1963

By Gene Asai

The Bureau of Mines investigated the caustic extraction of alumina and soda from retorted dawsonite-bearing oil shale, as part of a program to devise technology for treating alternative domestic sources of alumina for the production of aluminum metal. Colorado oil shale yielding 13 pct oil (35 gal/ton) and containing 12 wt-pct dawsonite (representing about 4 pct extractable alumina) was retorted to obtain oil-free (spent) shale Spent shale was leached with dilute NaOH to determine the effect of particle size, retorting temperature, leaching variables, and storage conditions on extraction of alumina and soda and dissolution of impurities. Maximum alumina and soda extractions were obtained by promptly leaching minus 28-mesh spent shale, obtained by retorting raw shale at about 5000 C, with 0.5N NaOH. Under these conditions, dissolution of impurities such as Ca, Fe, Ti, and P was low. Leaching tests were made on spent shale stored for periods of up to 30 days at 0° to 42° C and at 0 to 100 pct relative humidity (RH). These tests indicated that significant reductions in alumina extraction would occur if spent shale were stored in ambient Colorado air under naturally fluctuating temperature and humidity.

Jan 1, 1983

By N. S. Dalal, X. Shi

"Electron spin resonance (ESR) spectroscopy has been employed to· examine the role of tetraperoxochromate( V) ions (Cro:-) and other Cr(V) species in the generation of hydroxyl (OH) radicals in the reaction of Cr(VI) with H2O 2 in biological media. In contrast to earlier suggestions, the present ESR studies using crystalline K3CrO8 as a source of Cro:- show that decomposition of Cro:- in water or in H2O 2 does not generate significant amounts of OH radicals. Addition of NADH to a solution containing Cro:- yields a Cr(V)-NADH complex, which readily reacts with H2O 2 to generate OH radicals. Similar results obtained from several other biological reductants, including vitamin B2 , indicate that a vacant coordination site on a Cr(V) complex facilitates its reaction with H2O 2 to generate ""OH radicals. We thus suggest that in biological media, reaction [3] instead of [1] or [2] is the major pathway for the OH radical generation: While the carcinogenic potential of Cr(Vl)-based compounds has been well established via epidemiologic and animal studies (1), the underlying biochemical mechanism is still not well understood (2). In a recent development, however, Kawanishi et al. (3) have reported that hydroxyl (OH)2 radicals might be the key species in the mechanism of Cr(VI) toxicity. As to the mechanism of the ""OH radical formation they suggest that Cr(VI) reacts with cellular hydrogen peroxide (H2O 2) to form the tetraperoxochromate(V) (Crog-) ions, which decompose to produce hydroxyl radicals. It was also suggested (3) that the ""OH radicals thus produced cause genotoxicity via DNA base modification and deoxyribose phosphate backbone alterations. More recently Aiyar et al. (4) reported the detection of OH radicals in the reaction of Cr(VI) with H2O 2 in biological media, including the reaction of ""OH radicals with deoxyguanosine to generate 8-hydroxydeoxyguanosine adducts, confirming that ""OH radicals could indeed play a significant role in the mechanism of Cr(VI) toxicity. However, the mechanism for the ""OH generation was not clarified, although the role of Crog- ions as possible precursors was mentioned, somewhat along the lines suggested by Kawanishi et al. (3). The possibility of the participation of Crog- in the ""OH generation has also been indicated by Sugiyama et al. (5), since they mention that vitamin B2 enhances the formation of""OH radicals in the reaction of Cr(VI) with H2O 2 because of the generation of Crog- in the reaction."

Jan 1, 1990

By C. H. Riggs

This petroleum-engineering report of the Atlanta oil field in BO them Arkansas reviews reservoir conditions and pressure-production history of one of the important Smackover limestone fields in southern Arkansas. The study of the field was made and the report prepared to aid operators in this and similar fields to increase the efficiency of recovery through the application of better engineering practices. A similar study of the Magnolia field in Arkansas by Carpenter and Schroeder was the first of these reports prepared under a joint agreement between the Arkansas Oil and Can Commission and the Bureau of Mines. The increasing demands for petroleum and its products and the steadily increasing cost of discovering and developing oil field; emphasize the importance of conserving known reserves of oil and gas. In recent years vast improvements have been made in the technique of oil recovery, both by better utilization of the natural energy stored in the reservoir and by improved methods of applying external energy to the reservoir system. This report may aid in oil conservation by careful evaluation of the several factors that did or did not contribute the greater recovery in the Atlanta field and by suggesting improvements in production methods and applications.

Jan 1, 1949

By Lloyd A. Morley

A guide to the development and use of an APL computer program for the analysis of load-flow problems is presented. The program is designed to provide an interactive method of load-flow study to improve underground coal mine electrical system design and safety. The theoretical basis for load-flow analysis is discussed, along with per-unit calculations which facilitate computation. Specific input/output, execution and network modification procedures are presented for using the APL program. In addition, typical results are given for examples taken from power system analysis literature.

Jan 1, 1977

By Gary W. Krantz

Fibered, portland-cement-based gunite products were applied in the Bureau of Mines Lake Lynn Laboratory Experimental Mine using a variety of pneumatic guns and gunning crews, The demonstrated wet-mix (with silica fume), dry-mix, and surface bonding products were sampled by the Bureau and subjected to a suite of engineering analyses. Gunite flexural and compressive strength, rebound, permeability, porosity, dust loading, shooting rate, crew requirements, and cost factors were evaluated. Steel, fiberglass, or polypropylene fibers were contained in all but two of the gunires tested. Both Bureau and private testing laboratory analyses are provided for some products. Electron probe micro-analysis and X-ray diffraction analysis were performed on the silica fume fraction of the wet-mix gunite to characterize the dust. Aggregate size fraction distribution analyses were performed to provide strength relationships. Results indicate that all of the commercially available fibered-gunite materials tested can provide beneficial sealant, spall prevention, or roof stability control attributes for underground mining environments when applied by an experienced crew using a well-maintained gun, in accordance with product manufacturers' recommendations and when used for the designated purpose.

Jan 1, 1984

By D. Harrington

The fiscal year which ended June 30, 1932, although one of acute financial de ression was, nevertheless, one of distinct encouragement to those who have long struggled against the much too prevalent occurrence of accidents in coal mines, especially of coal mine fire and explosion dis- asters, both of which are now known to be readily preventable. Table 1 summarizes some important information about explosions in the United States coalies for the fiscal year which ended June 30, 1932, insofar as such information is available to the safety division of the United States Bureau of Mines, the personnel of which are under instruction to get in touch with and report on all mine explosions in their respective districts, including not only those occurrences with loss of life but also those in which for- tunately no lives, are affected. Table 1 gives data on 33 ignitions in 10 States with a total of 87 deaths for the year; the number of ignitions (33) is considerably groater than the number (26) for the previous fiscal year, and is exactly the aver- age number for the past four fiscal years; the mumber killed in the 33 ignitions (57) is materially lower than that (217) for the preceding fiscal year or the average (150) for the past four fiscal years. The States with the greatest number of deaths from explosions in the fiscal year ending June 30, 1932, were Virginia; 54; West Virginia, 11; Pennsylvania, 7 (6 being in anthracite mines); Alabama and Colorado, 4 each; Illinois and Kentucky, 3 each; and Maryland, 1. The greatest number of ignitions listod wes that for West Virginia, 7; then came Pennsylvania with 6 (2 being in anthracite mines); Alabama with 5; Colorado, Illinois, Tennessee and Virginia, 3 each; and California, Kentucky, and Maryland, 1 each. The 1931-32 record as given in Table 1 includes several States which were not listed in the previous year: Colorado, Kentucky, Maryland, Tennessee,

Jan 1, 1933

By R. J. Hundhausen

"INTRODUCTION Preliminary examination of the Blue Ledge mine was made by O. H. Metzger, a Bureau of Mines engineer, in May 1943. A result of his recommendations; a Bureau of Mines sampling and exploration project was begun by J. R. Reynolds in October 1943 and continued to December when it was recessed for the winter. The project was resumed by the auther in May 1944 and was completed in November 1944. The Federal Geological Survey 3/ assisted by mapping the geology of the mine and logging the diamond-drill cores obtained from the Bureau's exploration Company maps, diamond-drill-hole records, several reports, and other data on the property were made available to the Bureau by D. C. Brown, of Towne Securities Corporation, owner of the Blue Ledge group of claims. E. A. White, general manager of the Tacoma Smelter of the American Smelting & Refining Co., supplied statistics for all ore that has been purchased from the Blue Ledge mine by his company."

Oct 1, 1947

By L. C. Brichta

During a study of the Badger-Peacock area from October 1950 to June 1953, the Federal Geological Survey and the Federal Bureau of Mines completed nearly 98 miles of resistivity profiling and drilled 96 test holes aggregating 17,628 feet of bore, In addition, seismic profile measurements were made along 8 traverse lines for an aggregate length of about 16,600 feet. The geophysical surveys were conducted by the Geophysics Branch of the Geological Survey; the drilling was done by the Bureau of Mines. Electrical-resistivity measurements disclosed 21 low-resistivity anomalies and 1 high-resistivity anomaly. Correlation of the resistivity data with the geological information revealed by the drilling disclosed that the low-resistivity anomalies indicated either slumped shale deposits in limestone sinks or undisturbed deposits of shale lying in erosional depressions in the limestone. The high-resistivity anomaly indicated hard, undisturbed limestone at or near the surface.

Jan 1, 1958

By G. B. Atkinson

The Bureau of Mines investigated a method for increasing the leaching rate of bulk superalloy scrap to facilitate recycling and recovery of critical metals such as Ni, Co, and Cr. Three superalloys were investi- gated, the cast-nickel-base superalloy IN-738, the wrought-nickel-base superalloy Rene-41, and the cast-cobalt-base superalloy Mar-M-509. Superalloys melted with 20, 30, 40, and 50 pct Al metal to form inter- metallic compounds were easily crushed to a convenient particle size and reacted rapidly with acid solutions which dissolved the metals. For example, leaching 1/2-in pieces of unalloyed IN-738 with excess 6N HC1 at 95° C for 2 h dissolved about 0.5 pct, while leaching 10 g of minus 20-mesh 30 pct Al-70 pct IN-738 with excess 6N HC1 at 95° C for 2 h dis- solved 96.2 pct.

Jan 1, 1983

By J. E. Geier

This Bureau of Mines report reviews hypotheses for the mechanism by which water jets reduce the specific energy of cutting for drag bits. Several of these hypotheses are shown to be inconsistent with published evidence and new observations. The notion of a limiting cutting speed, above which water jets would be incapable of rendering assistance, is shown to be improbable. The hypothesis that seems most plausible is that specific energy reductions are mainly due to the erosion of crushed materials from in front of the bit. This hypothesis leads to a prediction that, for a given rock type and jet-bit configuration at a constant depth of cut, the reduction in bit forces should be a function of dM/dx, the jet energy spent per unit length of cut. This dependence upon dW/dx is shown to be consistent with other workers? results.

Jan 1, 1987

By C. E. Jordan

The Bureau of Mines is conducting research into the pneumatic recovery of coarse mica and has used this method to produce mica concentrates that contain more than 90 percent mica. This research is being carried out pursuant to the Bureau's objective to develop technology that will help maintain an adequate supply of minerals and metals to meet national economic and strategic needs. Researchers used a Bureau-designed system of crushers, screens, and zig-zag air classifiers to concentrate coarse liberated mica particles from mica-bearing materials. This pneumatic system was used to concentrate four mica ores from Arizona, North Carolina, and South Dakota and three waste tailings from Alabama, Georgia, and South Dakota. Using these samples, it was demonstrated that plus 65-mesh size mica can be effectively recovered by the pneumatic method. Not only were the concentrates high in mica content; it was also demonstrated that this method can be used to recover up to 78 percent of the mica that was originally contained in the samples. Because it is a dry concentration method, the pneumatic beneficiation technique may be advantageous in areas where water resources are limited.

Jan 1, 1980

By W. W. Adams

The year 1937 was signalized by increased employment in the metal-and nonmetal-mining 4 industry of the United States. Measured by the number of men working, there was a 17-percent gain in employment compared with 1936. In total number of man-hours worked at all mines, the gain was slightly over 18 percent. Hazards connected with mining resulted in more accidents to the workers than in 1936, but the increase in number of accidents caused only a slight rise in the accident rate because of the much larger increase in the number of man-hours worked. In fact, the fatality rate per million man-hours of exposure was lower in 1937 than in 1936, but the rate for nonfatal injuries increased slightly.

Jan 1, 1940

By F. M. Boler

The U.S. Bureau of Mines has configured a flexible data acquisition and analysis workstation, which incorporates control and analysis software written in-house for use in mining research experiments conducted in the laboratory and in operating underground mines. This data acquisition system combines computer-automated-measurement-and-control (CAMAC) modular instrumentation with a Unix-based graphics workstation. The data acquisition front-end hardware can be interfaced to almost any computer. CAMAC instrumentation modules adhere to mechanical, electrical, and digital interface standards and can be custom designed or purchased off the shelf. Communications along the CAMAC bus are regulated by the crate-controller module, which contains the only hardware link to the computer interface. Software support for the data acquisition and analysis workstation consists of a series of functions and programs written in the "C" programming language designed to provide flexible and fast data acquisition, processing, and analysis. The user can interactively control the digitizers and other CAMAC modules by sending standard CAMAC read, write, and command function codes from a menu-driven program. Automated data collection is achieved through software that responds to hardware interrupts triggered by acoustic emission or microseismic events. Graphics display routines are used to plot part or all of the data and provide the ability to process and store signal information selectively.

Jan 1, 1990

By Edward P. Barrett

The production of sponge iron is one of the earliest arts in the metal¬lurgy of iron and steel. The idea of producing iron direct from ore at temperatures lower than the melting point of, the iron has persisted throughout the centuries. The purpose of this paper is to present a general picture of the methods, proposed or tried within the past 100 years, for producing sponge iron by treating hot ore with heated reducing gases. The abundant literature has been abstracted, and quoted freely. Publications concerning more detailed information on the various methods are referred to in the footnotes and in the bibliography.

Jan 1, 1949

By S. W. Zoldok

[The Bull Valley iron-ore district lie,; in the northern part of Washington County, Utah, approximately 30 airline miles southwest of the highly productive Iron Springs area (fig. 1). Iron-ore occurrences in the district have been known for many years, but they have not been mined, largely because of the inaccessibility of the area. The Bureau of Mines established a development project in the Bull Valley district in September 1941. Two separate areas, the Pilot and the Cove Mountain, were investigated. The work was planned to increase iron-ore reserves for steel production in the Western United States. During the project period three diamond-drill holes aggregating 1, 000 feet were completed (fig. 2). The program also included 6 408 linear feet of surface trenching and 171 feet of underground work (figs. 2 to 8, inclusive). Analyses were made of 460 samples from the diamond-drill holes and surface and underground excavations. The results of the analyses are given in tables 1, 2, 4, and 5, and the logs of the diamond-drill holes are shown in table 3. Field. work was completed in September 1942.]

Jan 1, 1953

By A. B. Hooker

Gassy mines require daily inspections with methane detectors to test for the presence of methane. Although in many manes it may be sufficient to know that there is no methane present or that its percentage is below a certain amount, it is desirable and often necessary to determine definitely the percentage of methane at the working faces and in the various air currents. The Bureau of Mines recognizes two general types of portable methane detectors, namely; 1. Methane detectors by which the presence of methane may be detected and its approximate percentage estimated.

Jan 1, 1929

By A. N. Fried

With the growing importance of fluid injection in recent years, the petroleum industry has been investigating and field- testing a variety of new methods designed to modify the physical properties of reservoir oil to improve the efficiency of gas and water injection. These procedures include condensing-gas drive, LPG (liquefied petroleum gas) injection, alcohol-slug process, high-pressure-gas displacement, detergent-solution flooding, and in situ combustion (30, 37).3 A new and different method to increase the effectiveness of gas and water injection has been tested by the Bureau of Mines, Consideration of both fundamental and practical factors that operate to limit the oil recovery attain- able by conventional oil-displacement mechanisms led to the concept of a displacement mechanism called the foam-drive method. This report describes the experimental study that tested this concept in the laboratory.

Jan 1, 1961