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By J. A. Kosek

Work has been carried out under Bureau of Mines Contract No. HO395132 to develop and fabricate gas sensors for mining applications. Promising new instruments have been designed, developed, tested and supplied to meet BuMines requirements. These instruments include prototype 1) remote-sensing, diffusion-type CO monitors for mine operation which can be operated in conjunction with a surface computer, 2) control modules for alternate in-mine readout of the remote diffusion type CO monitors, 3) personal CO diffusion-type dosimeters and 4) personal NO diffusion-type dosimeters. In addition, retrofit modifications were made to update and optimize operation of CO and NO2 direct-reading type detectors provided under a previous contract. Studies were conducted to evaluate and demonstrate the availability of stable, portable N02 calibration sources for NO2 instrumentation. The use of selected, commercially available cylinder sources for NO2 instrument calibration were recommended. Additional studies were also conducted to investigate the feasibility of instrumentation for rapidly monitoring CO, NO and NO2 in diesel exhaust.

Jan 1, 1981

By J. Ran

There are challenges in mining deep tabular ore deposits using the open stoping method, particularly mining remnant panels towards the end of mine life. The remnant panels have experienced stress concentration and are in the failing or post failure state causing drilling and loading difficulties, ground movement, induced seismicity and ground instability problems. As more mines are going deep, without effective ground control management, the mine production will be interrupted and equipment damage and personnel injury are likely to occur. Mining at Falconbridge Lockerby Mine located in the Sudbury Basin was concentrated in the deep zone from late 1990s to 2004. The remnant panels situated approximately from 1800m to 1920m below surface were mined in 2004 before the mine closure. These panels were in the central section of the orebody along strike. The orebody was relatively narrow ranging from 5m to 15m and steep dipping at 70o to 80o. Because of the retreat mining sequence and the mining depth, stress concentration, wall closure and seismicity had caused a number of mining difficulties. Managing these challenges was critical in achieving the mine production target without compromising personnel safety and excavation stability. A comprehensive ground control management approach was adopted to mine the remnant panels at depth. The measures taken included ground movement monitoring, understanding the movement pattern of the footwall rock and selecting appropriate support systems, analyzing seismic monitoring data and defining re-entry protocol, brow support design and restricting access. This paper presents these ground control measures and the experience gained in successfully mining the deep remnant panels at Lockerby Mine.

Apr 1, 2005

By J. W. Jensen

This report was prepared as a background reference for future publica¬tions concerning the damping capacity of metals and alloys. It contains a broad description of the theory and methods of measuring damping capacity and correlates the developments of the past decade in terminology, units, and techniques. Damping-capacity instrumentation at the Mississippi Valley Experiment Station, Rolla, Mo., is described. The bibliography contains over 150 references to recent articles, each tabulated as to material investigated and test variables, such as frequency, stress, mode of vibration, and temperature. INTRODUCTION After it discovered high-damping manganese-copper alloys before World War II, the Bureau of Mines began research on the damping capacity of alloys and has continued to expand this activity to the present time. In physical metallurgy, damping capacity has become an important research tool in the Bureau. The physical measurement of the damping properties of alloys was begun at the College Park laboratories, and later conducted at Salt Lake City under the direction of Dr. E. V. Potter. Among the many articles resulting from this work, Damping Capacity of Metals (108)3/ has received frequent men¬tion in more recent literature and describes briefly the methods of measurement employed at that time.

Jan 1, 1959

By Charles H. Dowding

Whenever piling vibrations are significant, construction activities associated with pile driving and/or excavation can produce permanent displacement. These permanent displacements are more detrimental to structural performance than the hair sized, cosmetic, plaster cracks that might be produced by slightly exceeding reasonable vibration controls. Case studies are presented which demonstrate the relative importance of permanent displacements compared to directly produced transient vibration displacement within a horizontal distance of one pile length. Special attention is paid to settlements produced by densification of liquefiable sands. SOURCES OF TRANSIENT AND PERMANENT DEFORMATION DURING CONSTRUCTION Confusion over multiple sources of facility deformation caused by adjacent construction complicates the discussion of the relative importance of vibration induced cracking. None of the recent scientific investigations of vibration induced cracking (Siskind et el, 1980), involved deformation other than that produced by ground vibration from rock blasting. Thus these studies carry the implicit assumption that no ground deformation occurred other than that produced by the transient vibration. In other words there is no permanent deformation other than that which is typical of the older residential structures investigated.

Jan 1, 1991

A production drill rig at a site in Sweden was equipped with a monitoring system to estimate production statistics. Drill running times, drill hole depths, penetration rate, rotation speed, thrust, air percussive pressure and torque pressure were recorded for every 10 mm of hole length for a period of 5 months. Operational activities (rock penetration, tube handling, moving and set-up time) accounted for almost 62% of the time consumed, the remaining 38% being different types of stoppage. Drilling itself, as opposed to handling, took less than 24% of the total time. The results give an indication of how the overall drilling capacity can be increased and which activity should be emphasised. The impacts of automation, new developments and reorganisation on production can also be predicted. Average production was found to be around 100 m/day, but varied between 50 and 160 m/d. The company's specification for the drill rig, before purchase, was that an average production rate of 130 m/d be attained over two consecutive months of drilling - a rate which monitoring shows will not be achieved

Jun 19, 1905

Effect of Grinding Media on the Flotation of Sulfide Minerals

Sep 13, 2010

H. DEAN JACOT RMCMI PRESIDENT 1987-1988 on behalf of The RMCMI Board of Directors and Officers The Rocky Mountain Coal Mining Institute cordially invites you and your family to attend the 84th Regular Meeting and Convention to be held June 26, 27 and 28, 1988 at Beaver Run Resort Breckenridge, Colorado

Jan 1, 1987

By Pedro Lilienfeld

This report describes the development, design, fabrication and testing of a port-able, battery-operated, light scattering monitor (henceforth to be designated as ILSDM) for the rapid measurement of the concentration of respirable dust in mining environments. This instrument incorporates state-of-the-art design characteristics and makes use of advanced solid-state components both for light emission as well as for its detection. The use of a pulsed light source combined with synchronous signal detection minimizes drift problems and optimizes the sensitivity of the measurement. Simplicity of operation, reliability and ruggedness, light weight as well as improved performance were salient objectives of this instrument development program. Continuous clean-air flow screening of all critical optical surfaces, and optimized optical detection and electronic signal processing design resulted in about a hundred-fold decrease of noise and drift with respect to precursor instruments. Equivalent mass concentration measurements 88 low as 10 micrograms per cubic meter can be routinely performed with time constants of about 2 second.

Jan 1, 1979

By P. H. Reynolds, S. Liaghat, A. Zarasvandi

"Darreh-Zerreshk and Ali-Abad are two relatively small porphyry copper-type deposits in Yazd Province in central Iran. They are located within the central Iranian volcano-plutonic belt, formed above the collisional convergent margin of the Iranian lithospheric plate from the late Eocene to the Miocene. This paper discusses the geochemical characteristics of the igneous rocks, and 40Ar/39Ar geochronology of plutons and alteration phases associated with the Darreh-Zerreshk and Ali-Abad deposits. The deposits are spatially associated with igneous complexes that consist of older and barren granites intruded by intermediate-composition granitoids, which are the carriers of Cu mineralization. The granites have relatively high content of Nb, Y, and K, a prominent negative Eu anomaly, and were probably derived from melting of, or contamination of mantle-derived magmas by, continental crust. Porphyritic diorites, quartz monzodiorites, and granodiorites show enrichment in light rare earth and large-ion lithophile elements, depletion in middle rare earth elements, and have no negative Eu anomaly. These intermediate-composition granitoids were derived from melting of the upper mantle or lower crust, and their differentiation was controlled partly by fractionation of hornblende. A pilot K/Ar whole-rock dating study suggests that the pre-ore granites were emplaced in the Oligocene. Dating by the 40Ar/39Ar method of nine samples of secondary biotite and sericitized rocks from drillcore within the mineralized and altered zones in both deposits yielded a well-defined age of ca. 16 Ma. This date is interpreted to be the time of hydrothermal alteration and of porphyry copper type mineralization in this part of Iran."

Jan 1, 2007

By I. McDougall

The matte/slag tidal zone in a nickel-copper-iron-sulphide matte smelting furnace is subject to severe process conditions that can lead to premature failure of the lining. The MgO-FeO-SiO2 slag is aggressive to refractory bricks, while the Ni-Cu-Fe-S matte is aggressive to water-cooled copper cooling elements, and can penetrate and sulphidize refractory bricks. A novel approach to the lining design was taken at a PGM smelting furnace, where an indirectly-cooled graphite ring was applied in the matte/slag tidal zone, with refractory bricks on the hot face. The graphite was cooled by the copper cooling elements in the slag zone, obviating the need for copper cooling elements in the tidal zone. In this paper the effectiveness of different lining designs utilizing varying degrees of cooling in the slag zone and slag/matte tidal zones is compared. In comparison to water-cooled copper in various configurations, cooled graphite shows promise as an indirect refractory cooling system in the tidal zone area of furnaces. Keywords PGM smelting, graphite, refractory lining, copper cooling elements, submerged arc furnace.

Aug 1, 2013

By Paolo Cavalcoli, Marco Ziller

"ABSTRACT: In the year 2010 the State of Denmark together with the Municipality of Copenhagen, launched a very important and complex Project : the complete construction of a new double Subway Line :the CITYRINGEN.Copenhagen is the capital with a metropolitan population of 1,9 million.This line is like a ring placed in the very town center which includes all the most historical and monumental buildings and churches, with a total length of 17 km, and the presence of 17 stations plus 4 service shafts.The buildings have been built in the last centuries in an area where the groundwater is near to the surface and there are lakes and channels: the techniques adopted were advanced for those times, but limited as far as regards settlements and resistance to horizontal movements.The soil consists in 2 main groups.1.Upper sediments of the glacial ages : thickness total = 5-20 m composed by clay- silt-sand-gravelcobbles- granite boulders and flint in blocs and in layers : frequency and size of these obstacles wherenot determined.2.Limestone layers : 2a. upper limestone : highly fractured ,highly permeable2b.Itermediate limestone : less fractured, medium permeability.2c. Lower limestone : almost not fractured, low permeability.2d Bryozoan limestone : composed by fossils with microscopic dimensionsIn all the limestone formations there are important layers of flint , having thickness variable up to 3 m and important extensions. Water : in a part of the areas of the Cityringen the water is drinkable and utilized in the public waternet.Pollution: there are polluted zones due to previous industrial activities. Benzene areas have been identified, and for those areas special protections against pollution have been implemented.METROSELSKABET ,the public owner of the Cityringen,has set as priority to operate for the construction of the Cityringen the full protection of the environment and the respect of all the stakeholders :Very strong limits for the exhausted gas emissions have been introduced, by far stronger than those applied from the State of Denmark, very strong limits for the acceptable noise emission. And last but not least very important safety measures and procedure to avoid any accident on site."

Jan 1, 2014

By Oliver C. Fursman

The Bureau of Mines undertook this investigation in order to determine the feasibility of producing commercially acceptable alumina and iron by application of the Pedersen process to high-silica, high-titania, ferruginous bauxites of the Pacific Northwest. Calcium aluminate slags were produced by smelting bauxite with coke and lime in an electric-arc furnace. Over 90 percent of the total alumina can be extracted by sodium carbonate solution from slags of properly controlled ternary-phase composition (CaO-Al203-SiO2) that are cooled slowly enough to permit adequate crystallization of the 2CaO-SiO2 and the calcium aluminate compounds. Most of the iron charged was recovered in the regulus; the slag contained about 2 percent iron (as iron oxide), regardless of smelting time.

Jan 1, 1968

By Edward W. Parsons

The transverse force developed by expansion-shell rock-bolt anchors on the wall of a drill hole as the bolt is tensioned was measured by the Bureau of Mines using a device specially designed and fabricated for attachment to a universal testing machine. Load cells equipped with electrical-resistance strain gages provided the data from which the transverse force, in pounds, was calculated. Seven different expansion-shell anchors were tested, and the ratio of transverse force to bolt-tension load was found to range between 0.98 and 1.94 to 1.0. The drag load appeared to be the major cause of the transverse-force variation, but the relative effects of individual factors that affected the ratio between the transverse force and the bolt tension were not determined.

Jan 1, 1968

By Lulie H. Crump

U.S. supply and demand data for petroleum and natural gas liquids, by States and regions, were tabulated for the years 1960 and 1965. Estimates arcs provided of State-by-State quantitative data for the petroleum and natural gas liquids industry that can be integrated into State, regional, and national energy balances by source, form, and consumer sectors, and used for determination of interstate and interregional energy flows. Tables 1-4 show the estimated total supply of petroleum available for consumption and the supply's distribution among the major consumer demand sectors (household and commercial, industrial, transportation, and electricity generation). To obtain summary figures for the major proportion of refined products by States, individual tables were compiled for the six major products (tables 5-16). To enable comparison of petroleum data with those for other energy forms, conventional volumetric data in barrels were converted to their British thermal unit (Btu) equivalents. Interregional shipments of crude petroleum and theoretical flow patterns for petroleum products are shown in figures 1-4.

Jan 1, 1969

By A. J. Hendron, J. E. Monsees

INTRODUCTION This paper is the outgrowth of work done by the authors to prepare the seismic design criteria for underground structures on the Southern California Rapid Transit District (SCRTD) Metro Rail Project. It is a follow-on to a similar paper presented at the October, 1984, ASCE National Convention (17). For design, the earthquake-induced distortions recommended herein are to be added to the normal static loading conditions for the underground structure. This design approach has been used by 18 section designers on the SCRTD Project. Preliminary results from two- and three-dimensional finite element solutions have partially verified the approach. Areas where additional research is needed for special cases are identified. EFFECTS OF EARTHQUAKE The effects of earthquakes on underground structures may be broadly grouped into two general classes -shaking and faulting. In response to earthquake motion of bedrock (shaking) , the soil transmits energy by waves. Seismologists identify various types of earthquake waves, but underground engineers are generally interested in the effects of transverse shear waves which produce a displacement of the ground transverse to the axis of wave propagation. The orientation of propagation is generally random with respect to any specific structure. Waves

Jan 1, 1985

By Harry K. Weatherbee

The paper presents a design case study for a four-story correction facility addition in south Boston, Massachusetts, supported on friction piles driven into the Boston Blue Clay. 356 mm (14-in.) square prestressed-precast (PSPC) concrete piles were selected as they were found more effective and economical. A static load test was performed where the pile was brought to "failure". The load test data were evaluated to estimate the Ultimate Pile Capacity as well as the Ultimate Unit Skin Friction (Adhesion) to serve as a design tool for friction pile projects in the south Boston Area.

Jan 1, 2003

By William C. Cooley

This study Identifies and evaluates deposits of noncoal minerals in the U.S. which are most amenable to be mined underground hydraulically and transported hydraulically. A method was developed to screen and compare mineral deposits including economic comparisons. The most applicable minerals for hydraulic mining by borehole monitor jets from underground entries are soft uranium sandstones In Wyoming in locations where water is available. This method with hydrotransport could improve the safety, health and economy of underground uranium mining. Soft oil-bearing sandstones in California and Texas could be mined and transported by this method more safely than by other underground mining methods. Other weak sandstones may be hydraulically mined economically. Man, minerals are too hard to be mined by monitor jet but are amenable to hydraulic transport and hoisting. Uranium sandstone in New Mexico is of interest because of potentially improved health and safety in transport and lower transport cost, Increases in mine output for potash, in New Mexico and trona in Wyoming can be achieved most economically by adding hydraulic hoisting when existing skip capacity is at its limit. Research is recommended to obtain site-specific data on the feasibility of mining uranium ores by monitor jets.

Jan 1, 1981

By C. R. Summers, J. N. Murphy

In response to the Coal Mine Health and Safety Act of 1969, mandatory noise standards have been developed that specify time-noise limits of mine personnel exposure. Most affected by elevated noise levels is the pneumatic roof bolter operator, both in terms of levels near or in excess of 115 dbA and in terms of length of exposure. Therefore, the principal emphasis of this Bureau of Mines report is on pneumatic drill noise control. It is not the intent of this report to suggest any drill redesign; instead, methods are suggested to reduce the noise level by complementing existing machines. An integral muffler system and a separate muffler system were tested in an attempt to lower pneurnaric drill noise levels. Pneumatic drills, when new, operate at about 115 dbA when drilling in sandstone. Using the drill muffler systems, it was possible to decrease the noise level of a 115 -dbA s rope drill to approximately 100 dbA.

Jan 1, 1974

By S. L. Crouch

An important class of mining problems involves excavations in planar seam or vein-type deposits. In many instances it can be assumed that the seam is at 'infinite' depth in a homogeneous, isotropic or transversely isotropic, linearly elastic rock mss, and that the normal to the plane of the seam is a principal stress direction. Rational planning of excavations in such deposits requires a knowledge; of the stresses and displacements induced by complicated, irregular excavation geometries in the plane of the seam. This problem previously has been solved either numerically or by means of an electrical resistance network analog. Both of these methods effectively simulate the mined portions of the seam as a dislocation in an otherwise continuous mass, and determine the complete solution in terms of the stresses and displacements at the seam. In both cases, the plane of the seam is divided into a number - say, M x N - of squares, and the solution to the problem is determined in terms of the solution to an M x N system of equations. The numerical approach requires that these equations be solved explicitly, while the analog; solves them instantaneously with current analogous to stress and voltage to displacement. A purely numerical solution of practical problems can require a substantial amount of computer time, particularly in situations that demand some sort of sequential analysis, either due to successive mining or to nonlinear behavior of the seam material. This report describes a combined analog-digital computer system for solving problems that are impractical when either device is used separately. The digital computer and the analog are interfaced so that the digital computer can receive information from the analog via a switching matrix and an analog to digital converter, and can activate points of the analog via another switching matrix and a set of digital to analog converters. The resulting hybrid system can be used to simulate arbitrary "stress-strain" characteristics for any portion of the seam by an iterative procedure similar to the initial strain method used in nonlinear finite element analysis. Thus, the hybrid system combines the speed of analog computation with the decision-making capability of the digital computer: the analog instantaneously solves the set of equations, and the digital computer decides how the initial strains must be altered for the solution to be compatible with the prescribed "stress-strain" characteristics for the seam material. The hybrid computer system has many implications for rational planning of underground excavations, since it allows practically any type of inelastic seam behavior or artificial support characteristics to be simulated. Inelastic seam behavior, for example, might be due to either rock failure or to time-dependent deformation.

Jan 1, 1974

By John H. Johnson

This report covers research which is directed toward the measurement and control of underground mine diesel emissions. The report consists of three separate reports presented as Sections 1, 2, and 3. Section 1 "Emissions Measurement Apparatus" (EMA 1) discusses the selection and evaluation of instruments and procedures to be used as part of a diesel tailpipe emissions dilution and measurement apparatus. The instruments selected for gaseous pollutants are the Energetics Science Inc.* E.S.I.) 2000 for CO, the E.S.I. 7000 for NO and N02, and the Fuji ZFP5 for C02. Particulate matter is presently measured with the Celesco 1013 Smoke Opacity Meter. The raw exhaust concentration of one of these constituents is used Lo calculate the dilution ratio. Either a modified high range E.S.I. 2000 CO instrument or a Daco Products Cobra C02 instrument can be used, but neither is totally satisfactory. The study also indicated that it may he possible to increase the sample collection time from 15 seconds to the total 30 seconds over which the engine can be loaded without increasing the probability of damaging the vehicle hydraulic systems. Section 2 "The Effect of Fuels, Catalysts and a Filter Trap on Drift Pollutant Concentrations" discusses research in the Mine Air Quality Laboratory. A Wagner ST5D LHD with a Deutz F8L714 engine was used to compare three exhaust aftertreatment devices and a muffler-only system. The effect of these four systems on CO, C02, NO and N02 and on total, soluble, sulfate, and solid particulate matter was measured in the drift and on the LHD. The filter trap successfully reduced particulate matter for both fuels without significantly increasing the concentrations of any of the other constituents. The PTX catalyst was effective in reducing CO, and soluble particulate, but significantly increased N02 and solid and sulfate particulate matter. The Oxy Cat catalyst tested didn't seem to he working on the gases, and it significantly increased sulfate, soluble arid solid particulate concentrations. Section 3 "Diesel/Coal Particulate Matter Characterization by Laser Raman Spectroscopy" covers basic research on a method for determining the percentage by weight of diesel particulate on a filter containing a diesel-coal mixture. Signal-averaged Raman spectra provide the necessary precision. The method developed is non-destructive and uses as-received filters requiring no sample manipulation. Particulate with diesel contents in the range of 10 to 50% by weight have been analyzed with accuracies better than 6%t of the mean value. A number of samples containing diesel-coal mixtures were characterized by the procedures developed and the results are analyzed in light of various spectral and other system variables including coal rank and form and diesel engine operating conditions.

Jan 1, 1982