Search Documents

By L. C. IlsLey

The Burrell methane indicator developed by Col. G. A. Burrell in 1915 was modified during 1918 to the " insulated type " Burrell indicator . Though this instrument has been used in mines since its first introduction , it was not formally approved as safe and efficient for use in gaseous mines until March , 1922. The indicator is built by the Mine Safety Appliances Co. , Pittsburgh , Pa . Approval No. 800 has been assigned to this company covering the device in the form approved . The principle of the Burrell indicator is fairly well known . It works on the same principle as the Haldane apparatus - measuring by means of a graduated scale , the contraction resulting from burning the methane content of an air and gas sample . A given aniount of the mine atmosphere to be tested for methane is taken into the indicator . This sample is then thoroughly shaken with the water in the indicator for one minute . The methane in the sample is now burned for two minutes by a heated platinum coil , which is energized by a small storage battery containing two Edison cells connected in series . After the glower or coil has burned for two minutes , it is disconnected from the battery , and the indicator is again shaken for The amount of contraction observed by reading the height the water rises in the U- tube of the indicator , which is calibrated to register the percentage of gas in the sample . The indicator as approved by the Bureau of Mines is equipped with an Edison M- 8 mine- lamp battery , and with a glass and scale graduated from zerɔ tɔ four per cent methane . The approval of a corbination service that is , an attachment for giving illumination from the same battery from which the platinum glower is operated has been withheld pending the development of a battery with larger capacity . - Under laboratory operating conditions , a single glower was capable of making at least 20 determinations if proper precautions were observed with respect to the use of freshly charged batteries . A battery should be allowed to stand off charge several hours before using in an indicator , as the peak voltage of a freshly charged Edison cell is abnormally high and is likely to send enough current through the glower to melt the platinum wire . Fifty-seven satisfactory operations were obtained from a completely charged battery . The point where the voltage of the cell fell below 2.3 volts with the glower attached was taken as the lower limit of successful operation . A voltage less than 2.3 does not permit the lower to burn at a temperature that will completely burn the gas in the air , thus giving a false indication .

Jun 1, 1922

By M. G. Cherniack, A. J. Brammer, D. R. Peterson

Over the past two decades, there have been significant reductions in industrial exposures to hand-arm vibration, especially when specific tools and work processes have been redesigned to incorporate anti-vibration and ergonomic principles. Nevertheless, Hand-Arm Vibration Syndrome (HAVS) remains a significant occupational health problem as disease symptoms continue to occur even when vibration exposure levels believed to incur low risks have been reached2. This inconsistency may be related to the methodology that is typically used to estimate workday vibration exposure levels, involving laboratory and/or very short duration field measurements coupled with estimates of overall eight-hour tool operation times determined from brief observations of tool tasks and/or self-reported surveys. One solution is to use small, commercially-available, personal vibration dosimeters to calculate, record, and display long-duration vector sums and energy equivalents of vibration. However, since these devices are attached to the worker and require tool-mounted accelerometers, they are incompatible with the worker performing normal duties involving putting down or changing tools. In addition, these commercial systems do not allow for the characterization of the transmission of vibration to the hand such as monitoring the mechanical coupling between the hand and the tool handle (e.g., grip forces). O’Boyle and Griffin showed that variations in applied force can alter vibration transmission characteristics by 50% or more indicating that the measurement of grip force is essential for modeling vibration transmissibility and vibration exposures5. In summary, a need exists for the development of a method and device that will more accurately characterize workday-long vibration exposures. Methods A portable, light-weight, Vibration Exposure Monitor (VEM) system was developed to record user-specific tool-operating times, vibrations, and grip forces throughout all, or a representative part, of a workday. It monitors frequency weighted and unweighted accelerations from a palm-mounted uni-axial accelerometer (Model 352C22, PCB Piezotronics, Depew, NY) and calculates exposure levels using the root-mean-square (RMS) and higher power mean values, such as the root-mean-quad (RMQ) and the root-mean-oct (RMO). Grip forces are also monitored using a palm-mounted force sensor (Model 400, Interlink Electronics, Camarillo, CA) from which average grip force levels and exerted grip extrema are calculated. At the core of the VEM system is a commercially available, battery-powered microcomputer (Tattletale, Model 8v2, Onset Computer, Onset, MA) with one megabyte of memory and eight analog channels using 12-bit sampling at a single-channel maximum of 100 kHz. Analog signal processing (i.e., anti-aliasing, with cutoffs at 4 and 1250 Hz, and ISO 5349-13 frequency weighting) is accomplished using custom circuitry that is directly interfaced with the microcomputer. An embedded C-based protocol governs the data collection from each channel

Jan 6, 2006

By E. J. Matson

"The Bureau of Mines has been investigating deposits of critical and essential minerals in the United States since 1939. Projects were set up on only the most promising properties.A preliminary examination of the Mount Hope mine was made in January 1943 by the Bureau's engineers, who recommended exploration by diamond drilling.The mine is in the unsurveyed portion of T. 22 N., R. 1 E., Mount Diablo base and meridian, south-central Eureka County, Nevada, 25 miles by road north of the village of Eureka. A partly graded and Graveled secondary road connects the mine and Eureka on U. S. Highway 50.Extensive sampling was done by the Bureau in February. 1943. Core drilling from the surface was started on March 15, 1944, and completed on April 2, 1545. The 16 holes drilled totaled 7,215 feet. The mining company also did extensive underground core drilling from April 21, 1944, to January 4, 1945. This report gives the results of core drilling supervised by the Bureau of Mines.The drilling program was designed to explore for extensions of the mineralization exposed in the mine workings. As a result of drilling, additional ore was found, and it is believed that this project has fulfilled the purpose for which it was planned.In its program of exploration 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 na¬tional security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples of ore and performs beneficiation test. Both these branches are under the supervision of Dr. R. S. Dean, assists director.With respect to this report special acknowledgment is due to Charles W. Merriam of the United States Geological Survey for his interpretation of the Mount Hope mine Geology and his cooperation throughout the project; Col. Leverett Davis, former lessee of the property; K. K. Hood, manager of the Mount Hope Unit, Callahan Zinc-Lead Co., Inc.; C. P. Knaebel, assistant manager, and M. P. Nackowski, geologist, of that company, for their help, and to the Sullivan Machinery Co. for its assistance."

Aug 1, 1946

[lllc purpabr at thla report Vd, Lu JeLermlnr the health ar1J sdfet?; Nene11Le a octatc?J ultll Lne oar L.t support Ydlll ..up.I,ated lu dltetllative cupPurt svsLem, larrellLty hcle.g uaeJ af the Len,::rat 1, UI.Jlng 11-al tl. .1 a d 1 c L V h S LIdl'. L dal. I -ten- lu L he tt I .. L'., etuJ I e. 11'? L_1,1'1,11 .Jtd.. it, ..urn,at'l core ,LuJICCill JhLdll, an.: ...,La -IL .utia_tel .an LI?r oar of -l: l,.!rl .a..a. Ma terI.I auJ ...11,mc[Ii -ldla,tutcle 11. LI.ac .uwIttIca Welt a, a.. V.alte,, L.. .:Ltail, ..,,L., uI. LuClu,alug) Lelll anci ur devel?puJ I.,r Cul r1 , all. ...~.,rLrI Vt,ILt 1.'ere ~e,1C L? .Lher Gentiaii m111cc t, UL.-rye a Variety o. a rL vyl I pp.1Ca:t..n:. 'a.la IrL ..,_wLeiti, Iapl,.III ,tall ~,..:. IL all, maLertdl c1,arait-erlstIcs, JIRICn,IUIIe. and laden ul1.1 ILc rrgatrelaeuls. ,1 r.? p.'rt .a pro-1Jd, labor rep altrlarnts Jdta and illtlitI ieS tie l,ealtll d?J ,atetV ISSUC ,u-1aled Wit su furl Wall a an, CJl,wttuctSOn, I'aLentiaI appll.at1ou:. Ior support Walt, ,a,. , a, sdV.u,L111 .., u.1 retreating lungval1, single -t r-, roar al,- pi r. [,-+ln, anJ SuhIU..,Ina, Sill] b1OpplllgL ale 1:111neated aid al? e.aIWRac AS Sddemcni LV pre,C'IIL..: .,f LI. Clabllhty r+t rlul,I.,y111I? ulg4,rt .I Le.l,lwlug,. Lr i,,,rCASC Lllc rtCVLLrS rat, u., retrc.+tlnp .unui.,11? ur L., elply, A d v Ctnp IuI-,wall in uer;-!y iy1ng seam, . 11111.a1L .a1,.'iI1.-I,.. nr S.IU1tIVlil a1 milItlI; Lust, La LIldnt;2S L.~ gey support Vait Id tdmcLera la dlaa presents,.]

Jan 1, 1980

By K. L. Erickson, Gerald A. Munson

"The need for spodumene as a source of lithia for war purposes led to the exploitation of the Edison pegmatite deposit 1-1/2 miles southeast of Keystone, S. Dak. The operation was conducted during 1943 and 1944 by the Lor Mining Co., Rapid City, S. Dak. Spodumene concentrates in the ratio of 15:1 were recovered by hand picking from a sorting belt. This method was expensive and wasteful of spodumene, owing to the small size of the crystals.Data4/ obtained by the Bureau of Mines indicates that blunging with hydroflouric acid or sodium hydroxide is a prerequisite to selective flotation. Results of tests by Denver Equipment Co., Denver, Colo., indicate that economic recoveries can be obtained in an alkaline circuit after desliming.At the request of the Lor Mining Co., K. L. Erickson, metallurgical engineer, was permitted to work in the pegmatite research laboratory to verify previous investigations and to determine problems that might be involved in commercial milling. The ensuing investigation indicated that electrolytes in the mill water produced a profound inhibiting action on the flotation of Edison spodumone.An investigation of mill water from various sources showed that some waters are suitable for the process and others are not. Subsequent testing showed that all of the available waters are suitable after treatment. The flotation of the Edison spodumene in an alkaline circuit after desliming and using oleic acid as collector is efficient and economical when the water does not contain impurities.In its program of exploration 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 exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B.Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples and performs beneficiation tests. Both these branches arc under the supervision of Dr. R. S. Dean, assistant director.As the work was of a practical nature, samples from possible mill-water sources in the southern Black Hills were obtained, and commercial softening and demineralizing methods were investigated. Data on various waters tested are given in table 1."

Jun 1, 1946

By F. F. Aplan

Separation of the slightly soluble minerals (Ksp? 10-10), one from the other is one of the more difficult tasks confronting flotation engineers. This study has focused on means of separating such prominent members of this class as scheelite, fluorite and calcite from one another. Some experimental work has also been done on the minerals magnesite, dolomite and apatite. Carboxylic acid-type collectors are commonly used industrially to float all of these minerals. Thus, the problem at hand is to ascertain means of achieving selectivity between minerals known to respond rather similarly in flotation. Four techniques have been proposed for the separation of minerals of this class from each other: 1. Control of potential determining ions 2. Use of stereo-specific collectors 3. Use of flotation rate differences 4. Use of selective activating and depressing compounds. This study was directed toward a cursory evaluation of each of these techniques, and each was found to be a possible method of achieving selectivity. Stereo-specific collectors -- those whose parking area may closely match the available adsorption site on one mineral but not on another -- are a possible means of achieving selectivity between scheelite, fluorite and calcite. Stereo-hindered carboxylic acid salts and sulfonates all show selectivity between the three minerals tested. Separations also appear to be possible by the controlled use of the lattice ions (e.g., Ca and [W0=4] for scheelite, CaW04), H+, [OH-, C0-3 and HCO=3]; all of them ostensibly potential determining in the systems studied. Flotation rate differences of the minerals as a function of pH under conditions of starvation collector usage also showed promise. Scheelite and fluorite float most rapidly with sodium oleate in slightly acidic (pH 4-7) solutions whereas calcite floats most rapidly near pH 10. Use of Mn++, Pb++, or other heavy metal hydroxy complexes as activators was seen to effect each of the slightly soluble minerals differently. This is in sharp contrast to the oxygen containing, relatively insoluble minerals, where all minerals respond in a similar manner to such activation procedures. Results indicate that all four methods outlined above may potentially be used to achieve flotation separation of the slightly soluble minerals. More extensive research should be undertaken to detail the spcific applicability of each of the procedures and to make a more complete evaluation of the effect of collector type and concentration, mineral type, pH and size effects.

Jan 1, 1983

By John J. Sammarco, Janet S. Flynt

This report (Independent Functional Safety Assessment Guidance 7.0) is the last in a nine-part series of recommendations and guidance addressing the functional safety of processor-controlled mining equipment. It is part of a risk-based system safety process encompassing hardware, software, humans, and the operating environment for the equipment’s life cycle. Figure1 shows a safety framework containing these recommendations. The reports in this series address the various life cycle stages of inception, design, approval and certification, commissioning, operation, maintenance, and decommissioning. These recommendations were developed as a joint project between the National Institute for Occupational Safety and Health and the Mine Safety and Health Administration. They are intended for use by mining companies, original equipment manufacturers, and after-market suppliers to these mining companies. Users of these reports are expected to consider the set in total during the design cycle. • 1.0 Safety Introduction (Part 1).—This is an introductory report for the general mining industry. It provides basic system/software safety concepts, discusses the need for mining to address the functional safety of programmable electronics (PE), and includes the benefits of implementing a system/software safety program. • 2.1 System Safety (Part 2) and 2.2 Software Safety (Part 3).—These reports draw heavily from International Electrotechnical Commission (IEC) standard IEC 61508 [IEC 1998a,b,c,d,e,f,g]and other standards. The scope is “surface and underground safety-related mining systems employing embedded, networked, and nonnetworked programmable electronics.” System safety seeks to design safety into all phases of the entire system. Software is a subsystem; thus, software safety is a part of the system’s safety. • 3.0 Safety File (Part 4).—This report contains the documentation that demonstrates the level of safety built into the system and identifies limitations for the system’s use and operation. In essence, it is a “proof of safety” that the system and its operation meet the appropriate level of safety for the intended application. It starts from the beginning of the design, is maintained during the full life cycle of the system, and provides administrative support for the safety program of the full system. • 4.0 Safety Assessment (Part 5).—The independent assessment of the safety file is addressed. It establishes consistent methods to determine the completeness and suitability of safety evidence and justifications. This assessment could be conducted by an independent third party. • Safety Framework Guidance.—It is intended to supplement the safety framework reports with guidance providing users with additional information. The purpose is to assist users in applying the concepts presented. In other words, the safety framework is what needs to be done and the guidance is how it can be done. The guidance information reinforces the concepts, describes various methodologies that can be used, and gives examples and references. It also gives information on the benefits and drawbacks of various methodologies. The guidance reports are not intended to promote a single methodology or to be an exhaustive treatment of the subject material. They provide information and references so that the user can more intelligently choose and implement the appropriate methodologies given the user’s application and capabilities. The guidance reports comprise parts 6 through 9 of the series and are listed below: [< 5.1 System Safety Guidance (Part 6).—This guidance supplements 2.1 System Safety. < 5.2 Software Safety Guidance (Part 7).—This guidance supplements 2.2 Software Safety. < 6.0 Safety File Guidance (Part 8).—This guidance supplements 3.0 Safety File. < 7.0 Independent Functional Safety Assessment Guidance (Part 9).—This guidance supplements 4.0 Independent Functional Safety Assessment.] [ ]

Jan 4, 2006

By Lynn Alcorn, Jeffrey Shawn Peterson

Data collected by the Mine Safety and Health Administration (MSHA) has shown that roof bolting machine (RBM) operators are the second most likely type of underground mining machine operator to be are over exposed to noise, per the MSHA Permissible Exposure Limit. In response to this, the Pittsburgh Research Laboratory of the National Institute for Occupational Safety and Health (NIOSH) has initiated a project to develop engineering noise controls for roof bolting machines. Key to this research is an evaluation of the duty cycle of a typical roof bolting machine operation and this paper presents the results of such an exercise for data collected at two cooperating coalmines. The evaluation entails a time motion study of an operators&apos; shift, logging each activity for time (e.g., tramming the machine, drilling holes, installing the roof bolt, etc.) and the noise levels associated with each task with a Larson Davis Spark 705+ dosimeter. NIOSH post processed the data to determine which tasks the operator devotes the most time to and the noise dosage accumulated during those tasks. These results provide insight into which portion of the operators&apos; duty cycle is the most prominent contributor to noise exposure and thus, where research activities for the development of engineering noise controls should be focused. It was determined that the task of drilling holes is the most significant source of the operators&apos; noise exposure and project research has focused on engineering noise controls to reduce the noise emissions generated during the drilling portion of the machine duty cycle.

By H. E. Harris

It has long been recognized that one of the principal ways of combating dust in coal mines is by means of water sprays. However, spray systems, currently in use, clog or plug frequently, thereby reducing the effectiveness of dust control aid, in turn, possibly increasing the health hazard to mining personnel. Moreover, the maintenance and replacement of spray system components, e.g., nozzles and filters, can be expensive in terms of direct costs of labor and material, and the consequent loss of production. Recognizing these problems, the Bureau of Mines sponsored a research project on the "Development of a Non-Clogging Water Spray System"; this project was carried out by Eastern Associated Coal Corp. The overall objective of this project was to develop a non-clogging water spray system suitable for use in underground coal mines. Since most of the dust formed is at or near the working coal face, emphasis was placed on face equipment such as a continuous mining machine. To accomplish this objective, a two-phase project was carried out. The first phase involved determining the causes of spray nozzle and spray system clogging, determining the availability of spray nozzles or systems that could be modified to be non-clogging, and developing a non-clogging water spray system. Phase two was concerned with the fabrication and the laboratory and field testing of a non-clogging system. In each phase, there were both laboratory and field investigations, and the results of these investigations are presented in this report.

Jan 1, 1975

By G. Boehler

The purpose of this program is to demonstrate the feasibility and practicality of noise control for secondary and tertiary crushers in surface non-coal mining plants and mills. It is a part of the broad Bureau of Mines program to reduce noise in mines to levels mandated in the Coal Mine Health and Safety Act. Utilizing the results of previous contractual research efforts in which noise levels of secondary crushers had been measured, two noise enclosures were designed and evaluated for the REXNORD Symons 7-ft diameter secondary and tertiary crushers installed at the Jackson County Iron Company, in Black River Falls, Wisconsin. The first enclosure had a circular shape following closely that of the crusher and was built up entirely of quick-release panels which can be handled by the crusher operator alone. The second enclosure was octogonal in shape and can be rapidly removed, partially or totally using an overhead crane. Both enclosures fully satisfy the noise reduction objectives and permit daily and long-term maintenance of the crushers. Cost analyses show the cost of the enclosure to be less than 10 per cent of the cost of the crusher, the cost of the octagonal enclosure being estimated at only 60 percent of that of the circular one, e. g. $15,000 against $25,000. It is concluded that the octagonal enclosure best meets the needs of the Jackson County Mining Company and it is recommended that an experimental enclosure be built at the earliest possible time, as proof-of-concept.

Jan 1, 1977

By F. A. Rutledge, B. S. Webber, J. M. Moss

"INTRODUCTION The United States, with its vast resources of relatively low-grade zinc been the world's leading producer of zinc -metal for many years. The expanded zinc production during the period, 1939-44, inclusive, was induced by favorable premium prices and has depleted the known ore reserves in the United States. The 1943-44 rate of zinc production cannot long be maintained in the United States, especially if premium prices are removed. Domestic zinc reserves, have been depleted to such an extent that it is doubtful if our mines will again be able to completely and continually fulfill the needs of this country.The Bureau of Mines, anticipating a postwar consumer demand for 550,000 to 750,000 tons of slab zinc and an additional 100,000 tons for use in paints and chemicals, sent two engineers to Sedanka Island in July 1945 to investi¬gate the deposits near Biorka Harbor.ACKNOWLEDGMENTIn its program of exploration 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 exploratory project as soon as practicable after its conclusion the Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples and performs beneficiation tests. Both these branches are under the supervision of Dr. R. S. Dean, assistant director."

Nov 1, 1946

By Virgil Miller, R. G. Knickerbacken

"INTRODUCTION The Bureau of Mines work reported by the Metallurgical Division 4/ in 1934 shows the possibility of producing artificial manganese ore by pre- ferential oxidation of manganese from spiegeleisen produced from manganiferous iron ores of the Cuyuna range, Minnesota. A three-step process is described as being capable of producing a ferrograde ore from this type of low-grade, domestic, strategic material. However, the melting temperature in the last step of the process that forms the manganese product is high, and the phosphorus content is not easily controlled. Also, the tenor of the manganese in the product is not comparable with other methods that use less process energy.Lofquist 5/ patented an improvement of the above three-step smelting method, in which sulfide was added to lower the melting point of the product.More recently, reputedly successful attempts have been made to reduce iron preferentially from manganiferous iron ores, simultaneously removing the phosphorus with the iron, by means of an unusually high temperature blast and excess coke.Anson G. Betts 6/ patented a process for the matte-smelting of manganese ores, in which the ore was mixed with pyrite and enough carbon or coke to serve as thermal energy and reducing, agent in a manner similar to the standard blast-furnace process. This process was intended to give pig iron, a manganese-iron matte, and a waste slag. Wood, Barrett, and Porath 7/ presented data on the treatment of low-grade, domestic, manganiferous iron ores and low-grade, domestic manganese ores by this Betts mattes pelting process."

Aug 1, 1942

By F. J. Wiebel

"INTRODUCTION As a result of a general survey of the iron-ore deposits of Califor¬nia, the Bessemer was one shown to offer possibilities of developing com¬mercial ore reserves. Surveying and exploring were done at the request of Congress for an investigation of raw materials for the production of steel.A wartime steel plant has been established at Fontana, San Bernardino County, and a backlog of iron-ore reserve for the maintenance of permanent steel industry on the West Coast will be of National benefit in the postwar period.W. D. McMillan, a mining engineer the Bureau of Mines, examined the property in May 1942, and it was reexamined by D. W. Butner, also of the Bureau, in October 1943. Geophysical work was done by the Bureau in 1944, and the property was explored by diamond drilling from April to August 1944 and February to SeptemberACKNOWLEDGMENTSIn its program of exploration 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 contri¬bution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, under the direction of Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, under the direction of R. G. Knickerbocker, chief, analyzes samples and performs beneficiation tests."

May 1, 1947

The development of the potential supply analytic system has advanced to the point that quantitative estimates of economically recoverable resources can be made as the final step of the traditional regional mineral resource assessment process. In 1983, the BOM and the ADGGS jointly developed a methodology to quantitatively assess the potential for undiscovered yet economically recoverable minerals within a designated geographic area. This methodology was first applied in the assessment of the undiscovered mineral potential of the Kantishna Hills, Alaska (White et al., 1987). At that time the assessment procedure combined a series of technical judgements regarding the major geologic, engineering and economic factors that influenced the occurrence and exploitation of mineral resources in the Kantishna Hills area. Since then the methodology has been further developed and enhanced, particularly with respect to the engineering and economic analysis components. The resulting Potential Supply Analysis System (PSAS) was recently used to evaluate the economic potential of selected types of undiscovered precious-metal deposits in the Tonopah quadrangle of Nevada (Gunther, et al., 1988) and, with some enhancements, has been used to estimate the&apos; economic value of the undiscovered mineral potential of the WMNRA/SNCA study area. The PSAS has been designed to address five basic questions about the mineral potential of an area: 1) What alternative states of geologic nature are possible in the area of interest (e.g. How many and what types of undiscovered deposits could be present and what might be their grade, tonnage and depth attributes?) ?;

Jan 1, 2011

By Claude W. Sill

In the usual volumetric determination of uranium, the solution containing uranium is reduced in a Jones reductor, yielding a mixture of trivalent and tetravalent uranium; the trivalent uranium is oxidized to the tetravalent state by bubbling a stream of air through the solution. The resulting solution of. Tetravalent uranium is titrated with a standard oxidant, generally sulfatoceric acid, dichromate, or permanganate; It seemed likely that the, same general procedure could be used in determining semimicro quantities of uranium if the conditions affecting the variables involved were understood more clearly than at present. In the method described below, the use of ferric sulfate to oxidize tetravalent uranium allows the titration to be made at room temperature in an essentially colorless solution with sulfatoceric acid. The latter oxidant its turn permits the use of the very stable indicator, ferroin, with its sharp color.., change and exactly reproducible blanks. Solutions of uranyl sulfate were prepared by diluting a stock solution that had been standardized gravimetrically according to the method of Lundell and Knowles (8).3/ Solutions of sulfatoceric acid were prepared according to the directions of G. F. Smith (12) and were standardized against arsenic trioxide in the presence of osmic acid according to the directions of Gleu. The cerium solutions were stored in 18-liter carboys fitted with siphon arrangements so that the bottles did not need to be opened and protected from light in a dark cupboard. Under these conditions, even the 0.01 N solution changed by less than 1 part per thousand over a period of about 6 months.

Jan 1, 1952

By Heber E. Peterson, Sill. Claude W.

"INTRODUCTION In the usual volumetric determination of uranium, the solution containing uranium is reduced in a Jones reductor, yielding a mixture of trivalent and tetravalent uranium; the trivalent uranium is oxidized to the tetravalent state by bubbling a stream of air through the solution. The resulting solution of tetravalent uranium is titrated with a standard oxidant, generally sulfatoceric acid, dichromate, or permanganate. It seemed likely that the same general procedure could be used in determining semimicro quantities pf uranium if the conditions affecting the variables involved were understood more clearly than at present. In the method described below, the use of ferric sulfate to oxidize tetravalent uranium allows the titration to be made at room temperature in an essentially colorless solution with sulfatoceric acid. The latter oxidant in turn permits the use of the very stable indicator, ferroin; with its sharp color change and exactly reproducible blanks.Solutions of uranyl sulfate were prepared by diluting a stock solution that had been standardized gravimetrically according to the method of Lundell and Knowles (8).3/ Solutions of sulfatoceric acid were prepared according to the directions of G. F. Smith (12) and were standardized against arsenic trioxide in the presence of osmic acid according to the directions of Glen (5). The cerium solutions were stored in 18-liter carboys fitted with siphon arrangements so that the bottles did not need to be opened and protected from light in a dark cupboard. Under these conditions, even the 0.01 N solution changed by less than 1 part per thousand over a period of about 6 months."

Jun 1, 1952

By W. P. Yang, L. B. Berger, G. W. Jones

"Any burning carbonaceous material, unless supplied with enough oxygen for complete combustion, will liberate carbon monoxide. Since tobacco in its many different forms consists largely of carbonaceous material, and duo to the conditions under which it is smoked (burned), carbon monoxide should be liberated. That this is true has been shown by Armstrong.***** who found that undiluted smoke from cigars contained in some tests more than 3.00 per cent carbon monoxide, the amount present depending upon the size and closeness of packing of the tobacco during manufacture and on the rate of burning.****** Cigarets gave much less CO, varying from 0.06 to 1.40 per cent. The rate of consumption and carbon content of the tobacco are not g.ven, so that a correlation of the values reported to conditions in closed spaces where people might be assembled are difficult, if not impossible.The Bureau of Mines is interested in the general question of carbon-monoxide hazards from tobacco smoke, mainly with regard to mine ventilation. In non-gaseous mines, especially metal mines, the question arises, whether, if groups of miners are permitted to smoke while working at unventilated faces or entries, would the accumulation of tobacco smoke in these places create an' additional hazards the to carbon-monoxide poisoning. The results should, in addition be of general interest in connection with ventilation of building and inclosed places where people may be assembled and smoking is permitted. The investigation described in this report was made with the above idea in view."

Oct 1, 1923

By Russell. Paul L.

"INTRODUCTION Preliminary reports by Bureau of Mines engineers 3/ and by the Federal Geological Survey 4/ suggested that exploration would discover substantial reserves of minable ore in the Contact mine, Grant County, New Mexico. During February and March 1943, a sampling program was conducted on this property under the direction of the author. This was art of a general survey of the manganese districts of southwestern New Mexico.In its program of exploration 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 exploratory project as practicable soon as after its conclusion. The Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocer, chief, analyzes samples and performs beneficiation tests. Both these branches are under the supervision of Dr. S. Dean, assistant director. With respect to this report, special acknowledgment is due to C. H. Johnson, district engineer for New Mexico, and E. D. Gardner, regional engineer, and his staff, of the Central Region of the Bureau of Mines at the time of this work in 1943; also to Kenworthy, metallurgist at the Rolla. Mo., Laboratory of the Bureau of Mines, for work on beneficietion of the ore, and Sherman K. Neuschel, geologist of the Federal Geological Survey, for assistance in interpreting geological data at the project."

Oct 1, 1946

Coaxial cable structures form the subject of substantial theoretical and experimental investigations either directly related, or which can be extrapolated, to the communications needs and environments of U.S. coal mines. Communication systems based on "guided" waves, of which "leaky" coaxial cables are one implementation, are attractive candidates for providing a range of communication functions primarily along haulage ways, and possible also within sections up to the working face. (However, there are still strong reservations as to whether a practical coaxial cable sys tem could provide sufficient communications coverage within a section. ) In this Part, we present the results of some theoretical calculations of the performance of leaky coaxial cable communication systems. We also analyze the applicability of the theoretical and experimental results obtained by other researchers to the needs of U.S. coal mines. In particular, this investigation has been focused on the utility of relatively low cost, conventional, flexible, coaxial cable at frequencies covering the LF through HF bands and extending into the lower part of the VHF band, as opposed to relatively high cost, special semi-rigid, coaxial cable* at frequencies in the VHF and UHF bands. There are three major design alternatives for coaxial cable communication systems considered in this chapter: • Base station feeding a coaxial cable with high surface transfer impedance (holes in outer conductor, e.g., braid construction). • Base station feeding a coaxial cable with repeaters (U.K. experiments). • No base station, direct communication via a coaxial cable with periodic radiative structures.

Jan 1, 1974

By P. J. Colbassani

Samples of mine atmospheres collected by Federal coal-mine inspectors during their inspections and investigations of coal mines, in accordance with provisions of the Federal Coal Mine Safety Act (66 Stat. 692; 30 U. S. C., sees. 451-483) are analyzed routinely by chemical methods at Bureau of Mines laboratories. When samples collected in open workings of nongassy coal mines at points not less than 12 inches from the roof, face, or rib contain 0.25 percent or more methane, the act requires the operator, during operation of such mine, to comply with the provisions of sec. 209, Title II, of the act, which pertain to gassy mines. The methane con-tents of such samples are determined by a physical method based on infrared absorption spectrometry to provide an independent check on analytical results obtained by chemical methods. This information circular describes the equipment and procedures used by the Bureau for determining low concentrations of methane in coal mine atmospheres by infrared absorption spectrometry. ACKNOWLEDGMENTS The authors are indebted to Dr. R. A. Friedel, Chief of Spectrometric Section, Branch of Coal-to-Oil Research, Bureau of Mines, for suggesting the analytical method and for furnishing valuable advice and assistance, and to J. A. Queiser of his staff for making exploratory measurements by this method; to Dr. M. G. Zabetakis of the Division of Explosives Technology for his assistance during the conduct of preliminary experimentation; and to L. B. Berger, Chief, Branch of Health Research, under whose guidance the equipment was procured and the work conducted.

Jan 1, 1958