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By Jr. Holmes

The Bureau of Mines drilled and sampled the more important magnesite deposits in the Currant Creek Mining District, White Pine County, Nev. The properties of the Ala-Mar Magnesium Co., Inc., and the Nevada Magnesite Co. were examined in August 1942 by D. W. Butner, engineer of the Bureau of Mines, to determine the advisability of investigating the deposits under the strategic minerals program. Development involving diamond drilling, trenching, and sampling was started September 1, 1942, and was completed in the latter part of November 1942. The deposits are on unsurveyed public land in T. 12N., B. 59 E., M.D.B.&M., in an area of high relief ranging from 7,300 to 8,100 feet in altitude. Both properties are situated northwest of the Tonopah-Ely Highway, U.S. Highway 6, from which a dirt road extends about 4.6 miles northwesterly, about 35 miles southwest of Ely, to the Ala-Mar property, and another dirt road extends about 10 miles westerly, about 26 miles southwest of Ely, to the Nevada Magnesite property. The magnesite occurs as irregular nodules, veins, and lenses in a bedded calcareous tuff formation, which overlies a group of volcanic rocks, and which is capped by remnants of rhyolite flows.

Jan 1, 1950

By F. K. Shelton, J. C. Stah, Ruth E. Churchward

A study of the hydrometallurgy and electrowinning of cobalt from various domestic ores has been in progress at the Boulder City, Nevada, Experiment Station since February 1940. Previous reports covering certain phases of this investigation have been published. This report covers the research and pilot-plant work on the production of cobalt metal from cobalt-copper ores from the initial experimental work on crude ore through continuous operation. The ore types were from the Blackbird District, Lemhi County, Idaho. The initial tests were made with concentrated ore which was received by air mail and these experiments were expanded both in size and scope. After the laboratory was continued, improved, and extended tests were reported. Sufficiently advanced, a continuously operated plant producing 250 pounds of electrolytic cobalt per day was operated from June 15 through July 15, 1944.

Jan 1, 1948

By Ralph J. Holmes, Victor Sharp, Steven J. Spencer, Kevin J. Davey, Jonathan J. Campbell, Peter L. Phillips, David G. Barker

"Improved measurement tools for monitoring and control of AG/SAG mill performance have a high level of interest in industry. Historically, acoustic emission monitoring has been widely used on SAG/AG/ball mills and hydrocyclones to provide new information on the conditions inside these devices affecting their performance. The current work was focused on a new technique using surface vibration monitoring of a number of pilot-scale and production-scale AG/SAG mills to yield insights into the events occurring in the mills. The development of relationships between signal analysis outputs and mill operating conditions can be used for soft-sensor measurement of mill process variables. The technique used an array of accelerometers mounted on the mill lifter bolts linked to a fast data acquisition system which monitored the surface waves generated during operation. Details of the system are presented. Mill operating variables were adjusted systematically to provide a wide range of operating conditions for surface vibration signal collection. The experimental approach is discussed.The signals acquired during the experiments were analysed using a range of techniques. The results show that strong relationships exist between measured vibration power (both total power and within certain frequency bands) and mill load level/power and mill speed. A new method for extraction of power spectral density and band power information on features of interest in a mill rotation cycle is also presented.These results show that single sensor analysis information from the surface vibration system can be used as soft sensor inputs for monitoring process variables such as mill load that until now, have not been reliably measured. System outputs also show considerable promise in the area of condition monitoring. An example of the signal analysis output is presented showing elevated vibration levels in an area with higher resultant wear. Eventually, it is considered that outputs from this system for process variable and wear condition monitoring will be key new inputs to an online AG/SAG mill monitoring and control system."

Jan 1, 2003

By Michael K. Watkeys, Charlesworth. E. GUY, Jacobus E. Potgieter, Anhaeusser. Carl R., Roger L. Gibson, Alexander F. M. Kisters

Abstract - Intrusive features of cupriferous noritoids from the deeply eroded Proterozoic granite-gneiss terrane of the Okiep Copper District in South Africa illustrate the emplacement of basic magmas into a mid- to lower-crustal environment. The small, easterly trending intermediate to basic intrusions of the so-called Koperberg Suite display a wide variety of geometries, occurrence and emplacement modes, including dike-, sill- and plug-like bodies. Coeval granulite-facies metamorphism, partial melting and ductile deformation of country rock gneisses during intrusion of the basic magmas led to emplacement and dilation processes of the intrusions which differ significantly from those described for dikes and sills at shallow crustal levels. Regional tectonic stresses are largely negligible due to very low differential stress (?1 - ?3) during deformation and intrusion, which permits emplacement at high angles to the principal compressive stress and which follows favorably inclined structural anisotropies. Dilation of the basic intrusions is largely determined by compositional differences of host rocks and occurs by thermal erosion, i.e., assimilation of wall rock gneisses. Low length-to-width ratios of basic to ultrabasic dikes and predominantly diaper -like outlines of mesocratic bodies are indicative of low viscosity contrasts between the mafic magmas and high-grade metamorphic host-rock gneisses. Buoyancy-controlled ascent of the basic to intermediate intrusions is expressed by a broad compositional zoning of basic bodies with respect to the granite-gneiss stratigraphy. Various intrusion modes within the stratigraphic column of the granite-gneiss sequence reflect a lithological and structural stratification of the seemingly homogeneous granite-gneiss terrane.

Jan 1, 1994

By Gökhan Çevikbilen, Ümit Karadoğan, Sevde Korkut, Berrak Teymur

This study proposes a methodology for dewatering of mine waste using a multistage process, combining geotextile tubes and anionic polyacrylamide (PAM), which accelerates the recycling process of water for aggregate mine waste facilities. For this purpose, waste from a rock quarry located in Istanbul was investigated. Flocculation tests revealed that the use of anionic PAM at an optimum dosage reduced sedimentation time and decreased turbidity. The compatibility of geotextiles and mine waste conditioned with different dosages of the effective PAM was evaluated by rapid dewatering tests, considering the water content of the filter cake, amount of infiltrated solid content, and rate of filtration. Geotextile dewatering tests were also performed on PAM-free and conditioned suspensions. The dewatering process was optimized by the use of a geotextile tube in two stages: (i) on the unconditioned suspension and (ii) on recovered PAM-conditioned leachate. Directing PAM-free non-hazardous soil-based material obtained in stage i to alternative beneficial uses is suggested, to minimize the volume of waste. Furthermore, recycling of the effluent obtained at the second stage of the proposed method will ensure more efficient water reuse

Sep 29, 2022

Safety rules for installing and using electrical equipment in and about coal mines covered in this information circular supersede those previously included in Bureau of Mines Bulletin 514, issued in 1952. This revision brings these rules up to date and more nearly in line with present operating and safety practices in the industry. The rules are intended to supplement existing Federal and State regulations, and no provision shall be construed to oppose or supersede any provisions of the Federal Mine Safety Codes, the Federal Coal Mine Safety Act, or the mining laws of any State. The rules were designed to permit progress, such as application of new or improved materials and equipment or use of new practices where these materials, equipment, or practices retain or improve the level of safety established by these requirements. It is hoped that they will fill the need for a concise edition for mine electricians and electrical engineers, especially those who do not have ready access to more detailed rules or codes.

Jan 1, 1964

Safety rules for installing and using electrical equipment in and about coal mines covered in this information circular supersede those previously included in Bureau of Mines Bulletin 514, issued in 1952. This revision brings these rules up to data and more nearly in line with present operating and safety practices in the industry. The, rules are intended to supplement existing existing Federal and State regulations, and no provision shall be construed to oppose or supersede any provisions of the Federal Mine Safety Codes, the Federal Coal Mine Safety Act, or the mining laws of any State. The rules were designed to permit progress, such as application of new or improved materials and equipment or use of new practices where these materials, equipment or practices retain or improve the level of safety established by these requirements. It is hoped that they will fill the need for a concise edition for mine electricians and electrical engineers, especially those who do not have ready access to more detailed rules or codes.

Jan 1, 1964

By K. E. Stanfield

[Asphalt and road oil are the principal products manufactured from Wyoming ?clack oils? which, because of their high asphalt an high sulfur content, are difficult and costly to refine into high-grade motor fuels, burning oils, and lubricants by pre sent methods. Accordingly, the remand for these asphaltic residuums for the construction of roads and other uses is a controlling- factor in the quantity of crude oil produced. The increasing utilization of special asphalts as inexpensive bonding, insulating, and waterproofing materials indicates the desirability of obtaining information on the yield and properties, of asphalts from Wyoming black oil to promote a wider and more stable caret for these asphaltic materials.]

Jan 1, 1941

By B. P. Watson

The first crush pillars on the Bushveld platinum mines were introduced at Union Section in 1978. Before the introduction of crush pillars, serious problems were experienced when stoping advanced to a point 30 m to 40 m on both sides of the centre gully. At least three to four stopes were collapsing per month. The introduction of the pillars stopped the stope collapses in the mining area where they were introduced. The residual stresses of these pillars were never measured; however, the successful elimination of the ?back-break? problem suggests that the original pillars had a residual strength of at least 8 MPa. Apart from back analyses, very little work has been done to determine the residual strength of crush pillars and only very recently have any measurements been made. The lack of knowledge in this field has resulted in pillars being designed based on experience. Concerns about stope collapses, similar to the Coalbrook disaster, have led to larger pillars being cut in more recent times. If such pillars were cut in brittle quartzites they would always fail violently but the ductile nature of the Merensky Reef generally allows large pillars to fail without bursting. Occasionally, however, one would burst in a working area. Increased incidence of bursting has been reported on some mines at deeper levels but most of these bursts occur in the back areas. Nevertheless, the incidence of bursting increases the risk of falls of ground in already dangerous areas, and the larger pillars decrease the extraction ratio. This paper describes the evaluation of stress measurements conducted in two boreholes over a crush pillar with dimensions 2.5 m x4.0 m, and a height of 1.2 m. Boussinesq equations for vertical and shear stress were used to analyse the original measurements and provide a stress profile across the pillar as well as the residual strength of the pillar. The results showed an unexpectedly high peak stress of 280 MPa at the centre of the pillar and a residual strength of 48 MPa. The reason for the high residual strength is suspected to be the result of the stiff environment under which the pillar failed and the small height of the siding on the up-dip edge of the pillar. More measurements should be conducted on several mines to establish a range of residual strengths for narrow crush pillars.

Jan 1, 2008

Jan 1, 1989

By Xiaodong Wang

A liquid metal flow generated by a magnetic field whose traveling direction is periodically reversed, the Reversed Traveling Magnetic Field (R-TMF) is studied. The modulation frequency ranges from 0 to 6 Hz. Ultrasonic Doppler velocimetry probes the generated fluid flow. Depending on the modulation frequency, a number of characteristic flow features are exhibited. A transition frequency (approximately 4 Hz) exists, above which the flow is no longer sensitive to the force modulation. Below this transition point, the amplitude of the velocity oscillation increases, and then below fm = 0.05 Hz, it saturates around a value close to that observed without any modulation. A theoretical model to obtain an analytical solution of electromagnetic force and to predict flow motion is developed, which is fairly in agreement with the experiments.

Jan 1, 2009

By J. W. Walkiewicz

The Bureau of Mines investigated alloys containing lanthanum (La), praseodymium (Pr), neodymium (Nd), cobalt (Co), copper (Cu), iron (Fe), and magnesium (4g) as possible components of a permanent magnet mate¬rial utilizing a cerium-free synthetic mischmetal (M) as a substitute for scarce samarium (Sm) metal. Magnets containing M-Co-Cu-Mg and M-Co-Cu-Fe-Mg were fabricated by powder metallurgy techniques and evaluated. A synthetic mischmetal (M20) containing 20 pct La, 60 Pr, and 20 Nd yielded the best overall magnetic properties. The M20-Co-Cu-Mg alloys had energy products as high as 13.2 MGOe, remanences as high as 7.89 kG, normal coercivities as high as 6.26 kOe, and intrinsic coercivities as high as 13.4 kOe. The best value of intrinsic coercivity, 22.9 kOe, was obtained with an M-Co-Cu-Mg magnet in which the synthetic misch¬metal contained 30 pct La, 50 Pr, and 20 Nd. These values compare favorably with those of the Sm-Co magnets fabricated and measured at the Bureau's Reno Research Center, which had energy product of 15.1 MGOe, remanence of 7.8 kG, normal coercivity of 7.5 kOe, and intrinsic coercivity of 27.4 kOe. Iron substitution for part of the cobalt resulted in a decrease of magnetic properties, although several percent iron can be added before a drastic loss of magnetic properties occurs.

Jan 1, 1983

By Payman Roonasi

Having knowledge of mechanism of magnetite formation is essential in a number of industrial processes including magnetite synthesis and corrosion of iron. In this study, magnetite nanoparticle was synthesized via two different ways; coprecipitation of iron (II) and (III) and oxidation of ferrous hydroxide. The samples were characterized using X-ray diffraction (XRD), Mid-Far IR spectroscopy, scanning electron microscopy (SEM), chemical analysis for determination of Fe II/Fe III ratio and ICP-MS for iron isotopic ratio (56Fe/54Fe) measurement. Since fractionation of iron isotopes depends on reaction rate and bonding strength, interpretation of the isotopic data with respect to the possible mechanisms is discussed. No fractionation of iron isotopes was observed for the magnetite synthesized by coprecipitation, whilst magnetite formed from ferrous hydroxide showed higher abundance of 54Fe compared to 56Fe in the beginning of reaction, implying the significance of the following reaction:

Jan 1, 2009

By Paul S. Goodman

Volume I This report presents the first national survey of miners' attitudes and opinions about their-work. The goal is to present attitudinal data that bears on coal production. Interviews were conducted in 26 mines with 2,000 miners. High levels of cooperation were exhibited by management, union and the employees. Data are presented about miners' attitudes about general aspects of their work such as pay, supervision, their jobs, etc. Another section of this report reviews opinions about specific aspects of work performance. Recommendations are presented.

Jan 1, 1985

By Spencee L. Willett

A sand and gravel deposit exists in the Wildrose Canyon Wilderness Study Area (WSA), Out it is limited to local use because of the distance from major markets and resulting high transportation costs. The WSA has no identified metallic minerals, oil, gas or other energy related deposits. INTRODUCTION The WSA encompasses 17,366 acres (7,028 ha) in the Panamint Range, Inyo County, California. Access to the area is by State Route 190, approximately 45 miles (72.4 km) east of Lone Pine, California and 16 miles (26 km) southwest of Stovepipe Wells, California (fig. 1).

Jan 1, 1983

By Bernard Lewis

During the past 10 years the technical investigations conducted by the Explosives Division of the Mine and Explosives Bureau of the Bureau of Mines have been described in a series of summarizing reports prepared by Wilbur I. Huff, consulting explosives chemist of the Bureau. These reports covered the…

Dec 1, 1947

By D François-Bongarçon

The theory of sampling (TOS), and therefore representative sampling, is based on three fundamental principles: sample correctness, which handles the search for non-bias; segregation, the effects of which must be eliminated or minimised; and variance control to help achieve the desired reproducibility. After briefly reviewing these very few, albeit essential first principles of Gy’s TOS, the state-of-the-art in TOS is examined through the prism of these principles and the prospects for the future are explored, with suggestions for further research where relevant. Regarding segregation, which is currently the focus of much research, new orientations are proposed. For correctness, which takes on a major importance when it comes to sampling devices, some new, important principles that have been put forth by recent research, are described in details.CITATION:François-Bongarçon, D, 2014. State of affairs and current research trends in theory of sampling fundamentals, including segregation and correctness, in Proceedings Sampling 2014 , pp 11–16 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 29, 2014

By Kenneth H. Johnston

The Weber pool in Washington County, Okla. (fig. 1), covers an area extending from 2 miles east and slightly north of Bartlesville, Okla., to a point approximately 2-1P tiles northeast of Dewey, Okla. The pool is a part of the area designated by the Standing Committee on Oil Field Nomenclature, Kansas-Oklahoma Division, Mid-Continent Oil & Gas Association, as the Bartlesville-Dewey field. In the following discussion of the geology, development, and exploitation of the Weber pool, the writers, by means of structure maps, cross sections through various parts of the reservoir, and tabulated development data and production statistics, have recorded salient information on a field that was developed before .1910 in an Area that has been repressured since 1926. The total oil production to January 1, 19.0., from the 2,639 developed acres considered in this report, was approximately 14 million barrels, or a recovery of about 5,3;2 barrels per acre, or 227 barrels per acre-foot. The production of the estimated 18 million barrels of recoverable oil remaining in the Bartlesville sand reservoir will require the initiation of additional secondary-recovery practices on some of the leases and the application of a more systematic repressuring program on others.

Jan 1, 1950

By Shahé Shnorhokian

Remnant pillars evolve towards the latter stages of mining in an orebody and act as repositories of mining-induced stress. It is therefore crucial to plan ahead as to their dimensions and location with respect to the local geology. A case study of a Canadian base metal mine was examined for the planned mining sequence scenario to identify the stress regimes acting on a future remnant pillar occurring between levels 4800 and 5100, near a brittle dyke. A mine-wide model was constructed in FLAC3D and input parameters included results from field measurements of the direction and magnitude of the principal stresses, and the geomechanical properties of the different formations. Prior to the study, the model was calibrated based on a 6-year record of mining-induced seismicity and rockburst events, focusing on large event clusters. The mining sequence followed at the mine was then used in the model to study the planned future extraction program around the remnant pillar. It is shown that the distance of the remnant pillar from the dyke and another orebody plays an influential role on the stress levels developed in the pillar.

Jun 1, 2012

By D. P. Tao, J. G. Groppo, R. Killmeyer, W. W. Wen, B. K. Parekh

Economical dewatering of ultra-fine (minus 74 m) clean coal slurry produced in column flotation to a 20 percent or lower moisture level will be an important step in successful implementation of the advanced fine coal cleaning processes. The main objective of the present study was to evaluate efficiency and effectiveness of three dewatering techniques, namely, hyperbaric, vacuum and screen bowl centrifuge, in dewatering of ultra-fine (D50 ~ 25 m) clean coal slurry produced by the `Ken-Flote' columns operating at the Powell Mountain Coal Company, St. Charles, Virginia. he hyperbaric filter using 3 bar pressure and 165o cake formation angle, provided a filter cake with 23.6percent moisture with a throughput of 800 Kg/m2-h and air consumption of 868 Nm3/t (460 scfm/t). The vacuum filter with 30 percent submergence provided a filter cake with 27.8 percent moisture with a throughput of 122 Kg/m2-h. The screen bowl centrifuge provided a dewatered product containing 32.9 percent moisture at a feed rate of 450 Kg/hr, however, the solids capture was only65 percent. Addition of 1 Kg/t of a cationic surfactant provided filter cakes with 19.1 percent, 23percent, and 34 percent moisture using hyperbaric, vacuum, and centrifuge, respectively. Similarly, addition of 0.5 Kg/ton of copper chloride lowered filter cake moisture to 20.7 percent and 24.8percent, using hyperbaric and vacuum. With the centrifuge no improvement in filter cake moisture was noted. However, use of 80 Kg/ton of `orimulsion' in the centrifuge provided dewatered product containing 26 percent moisture, and the solids capture increased from 65 to 95 percent. The dewatered product appeared dry and was easily handleable.

Jan 1, 1999