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By L. Larson

Rock samples were taken, away from zones of mineralization , from seven sections of five rhyolitic zones as define d by Spence (l967) in the Noranda area. The purpose of the investigation was to test whether there were intrinsic differences between the zones which would differentiate between non-productive zones and productive zones. For the elements sought (major elements, Cu , Pb , Zn and S) , no clear chemical difference between the zones was found. Thus, identification of a favour able zone from the over -all composition of the zone does not appear promising. Within sampled sections, there is no clear gradual compositional change up through the sections. A capping of highly siliceous massive rhyolite is present in five of the sections sampled. A layer of relatively basic material occurs near the base of individual units. The third (mine zone) and later zones contain abundant pyroclastic material, where as the non-productive zones do not.

Jan 1, 1977

By Mehmet F. Taner

"Abstract - The East Sullivan Stock (ESS) is a small, composite felsic alkaline pluton of presumed late Archean age in the Val d’Or mining district. Three main facies have been distinguished: monzonite sensu stricto, porphyritic monzonite, and green trachytic porphyry. This monzonitic group of rocks is of relatively homogeneous composition with high abundances of Na2O, K2O, Ba, Sr, Rb, Zr, Mo and LREE. The alkaline ESS is distinguished from other igneous units in the Val d’Or mining district, such as the Bourlamaque Batholith, by relatively high concentrations of Ba, Sr, Rb, Mo, Cu and Au. The ESS hosts many base (Cu, Mo) and precious (Au) metal occurrences, including: (1) porphyry style Cu-Au-Mo disseminated sulfide deposits, (2) Cu-Au deposits in volcanic rocks near the ESS contact, and (3) pyritic gold mineralization in east-west trending shear zones. The ESS is well defined by concentrical zoning on the aeromagnetic vertical gradient color map, and displays four linear trends, which are assumed to be structural lineaments, at 035°-055°, 320°-300°, eastwest, and north-south. The main mineral occurrences related to the stock display a preferred spatial association with the east-west linear magnetic trends.The ESS is preferentially located along a major structure and was emplaced late in the evolution of the Abitibi subprovince like other felsic alkaline plutons. This stock is similar to late-tectonic mineralized felsic alkaline intrusions of the Kirkland Lake and Larder Lake mining districts in Ontario, and to the Allard stock in the U.S.A. which is associated with gold and base metal mineralization. Similarities also exist with younger alkaline plutons associated with Cu-Mo-Au porphyry deposits in the Canadian Cordillera, which formed in tensional tectonic environments. The felsic alkaline magma may have formed by partial melting of deeply buried supracrustal rocks, concomitant with the development of deep fractures such as the Cadillac Fault. In such an environment, hydrothermal solutions carrying remobilized metals from deep supracrustal rocks may have deposited gold and base metals in structural traps. Plutons similar to the ESS should be good targets for mineral exploration. Résumé - Le Stock de East Sullivan (SES) est une intrusion composite alcaline d’âge tardiarchéen, situé dans le camp minier de Val d’Or. Trois principaux faciès ont été identifiés: une monzonite sensu stricto, une monzonite porphyrique et un porphyre trachytique vert. Les données chimiques montrent que ce groupe des roches monzonitiques est relativement homogène en composition avec des concentrations élevées de Na2O, K2O, Ba, Sr, Rb, Zr, Mo et ETRL, définissant une suite alcaline typique. Cet alkalin stock peut être facilement distingué des autres unités géologiques de la région de Val d’Or, tel le batholite de Bourlamaque, par une concentration élevée de Ba, Sr, Rb, Mo, Cu et d’Au. Le SES contient plusieurs importants prospects de métal précieux (Au) et de métaux de base (Cu, Mo), incluant: (1) une minéralisation disséminée de type porphyre Cu-Mo-Au, (2) une minéralisation de Cu-Au dans les roches volcaniques encaissantes hôtesses près du contact et (3) une minéralisation d’or pyritique dans une zone de cisaillement de direction est-nordest. Le SES est bien défini sur la carte aéromagnétique en couleurs du gradient vertical par des zonages concentriques, où quatre linéaments structuraux ont été reconnus: 035°-55°, 320°-300°, est-ouest, et nord-sud. Les principales zones minéralisées spatialement associées au stock sont généralement situées soit près des linéaments magnétiques est-ouest, soit le long de ceux-ci.Le SES semble s’être mis en place le long d’une structure majeure, développée tardivement dans l’évolution de la Sous-province abitibienne, comme les autres plutons alcalins felsiques. Ce stock est similaire à la suite tardi-tectonique d’intrusions alcalines minéralisées des camps miniers de Kirkland Lake et de Larder Lake en Ontario, ou"

Jan 1, 1996

Professor R.P. King holds a Ph.D. degree in chemical engineering, which he obtained at the University of Manchester in 1963. After that he lectured in the Departments of Chemical Engineering at the Universities of the Witwatersrand and Natal. From 1968 to 1973, he was Leader of the Chemical Engineering Research Group of the National Institute for Metallurgy at the latter University. Mr C.E. Fivaz, Pr. Eng., is Chief Consulting Metallurgist of Rand Mines (Mining & Services) Limited, and is responsible for the metallurgical activities of the Gold and Uranium Division and the Coal and Base Minerals Division of the Group.

Jan 1, 1984

By Leonard Obert

[Part I of this report3/ proposed a sonic method for determining pressure, in situ, on rock pillars, arches, and other structures. Tin r Loa required (1) a laboratory determination of the variation of the velocity of sound with pressure in samples of rock taken from mine pillars to establish a velocity pressure relationship for the type of rock, and (2) a measurement of the velocity of sound in the mine pillars from which the laboratory samples were taken. The pressure on the pillars could be determined by correlating the velocity in the pillar with the velocity-pressure relationship established in the laboratory. The success of this method depends on the extent to which velocity of sound varies with pressure. Furthermore, Young's modulus of elasticity, E, can be calculated from longitudinal velocity, V, by the relationship, E V2d .....(1) where d = density. Hence, the variation of the elastic modulus with pressure also can be determined. It pointed out that this method might be extended to assist in the prediction of rock bursts, inasmuch as the rock is subjected to extreme pressure in these instances.]

Jan 1, 1940

By William S. Heckman

a. When to use: high surcharges, vertical capacity required, limit noise and eliminate vibrations, low headroom, eliminate vibration induced settlements. b. Advantages: eliminates impact noise and vibrations, high section modulus if required, vertical load bearing capacity; corrosion resistant, easy to apply facing for use as a permanent wall, adapts to complex wall layouts, would allow top- down construction, very high uplift resistance. c. Disadvantages: spoil disposal, not water tight, cannot penetrate rock and most obstructions, soil can erode between the piles if surface water and ground water are not controlled, hard to install reinforcing beams over 409 long; subject to high negative skin friction loads, high grout takes in rubble and organic soils. e. Relative cost to other systems: 30% to 50% more expensive than driven soldier piles and lagging except when surcharge loads are involved, or the pile cannot be driven due to noise and vibrations. About the same cost as a sheet pile system. Very competitive if high vertical load must be supported by the wall.

Jan 1, 1997

This document is Volume II of a two-volume report on underground and surface coal mine fires occurring between 1950 and 1977. Volume I discusses the methods of data acquisition, data analysis procedures, results and conclusions. This volume contains (1) a master list of all fire incidents obtained from MSHA reports, (2) an annotated bibliography of all MSHA reports, journal articles on selected incidents, and non-reportable fires (appendix), and (3) indexes to be used in accessing incidents in the master list and annotated bibliography. These three types of information provide the reader with a complete summary of coal mine fires during the period from 1950 through 1977 and a convenient means to locate incidents of specific interest. The body of this volume is organized around two tables and a series of indexes. The two tables are master lists of underground and surface fire incidents. They are followed by 14 indexes keyed to the master list and annotated bibliography. The appendix contains three different parts: o The annotated bibliography of MSHA fire reports (one section each for underground and surface mine fires) o The annotated bibliography of journal articles about selected fires from the MSHA bibliography o A listing of non-reportable fires (one section each for underground and surface mine fires) Descriptions of the contents and use of each of the three major components of this volume (i.e., master list, indexes, and appendix) are presented in Section 2.0.

Jan 1, 1979

By Leonard Obert

Part I of this report3/ proposed a sonic method for determining pressure, in situ, on rock pillar, arches, and other structures. The method required (1) a laboratory determination of the variation of the velocity of sound with pressure in samples of rock taken from mine pillars to establish a velocity pressure relationship for the type of rock, and (2) a measurement of the velocity of sound in the mine pillars from which the laboratory samples were taken. The pressure on the pillars could be determined by correlating the velocity in the pillar with the velocity-pressure relationship established in the laboratory. The success of this method depends on the extent to which velocity of sound varies with pressure. Furthermore, Young's modulus of elasticity, E, can be calculated from longitudinal velocity, V, by the relationship, E = V2d ...(1) where d = density. Hence, the variation of the elastic modulus with pressure also can be determined. It pointed out that this method might be extended to assist in the prediction of rock bursts, inasmuch as the rock is subjected to extreme pressure in these instances.

Jan 1, 1940

By R. V. Petrella

The flash induced combustion of Sewell and Pittsburgh coals was studied in air and in oxygen. The primary decomposition and combustion processes occur within the first 300 ~sec in oxygen and slightly later in air. Strong absorption spectra of CN and OH are indicative of the decomposition and combustion processes, respectively. Kinetic spectroscopy and combustion product analyses indicate that only about 35% of the coal dust is consumed in the explosive combustion which takes place in several (1-5) distinct but similar steps. The combustion-modifying effects of (NH4)2HP04, NH4H2P04, KHC03 and Rock Dust were studied in the 1-20 wt % range in coal dust flash com-busted in air and oxygen. The study reported herein shows Rock Dust to be the most efficient coal combustion inhibitor. KHC03 is the least effective agent, with the phosphate salts showing marginal effectiveness.

Jan 1, 1976

By D. Duff, R. A. Cameron, R. E. S. Whitehead

"Although CO2 content indicates the quantity of carbonate in altered basaltic rocks, it does not measure the intensity of carbonate alteration. CO/CaO molar ratios, which correlate with the relative proportions of individual carbonate species, measure the intensity of carbonatization. The Timmins gold area is characterized by pervasive carbonatization, with large parts of the area having CO2/Ca0 ratios greater than 1, representing C02 supersaturation relative to CaO. The mean CO/CaO in the Timmins area is0.67, compared to 0.13 in two unmineralized control areas. Regional arsenic abundance in the gold-bearing area averages 4 ppm, compared to about 0.35 ppm for the non-mineralized areas. The average K20 and Rb abundances are similar in both mineralized and non-mineralized areas (about 0.30% K20 and 7 ppm Rb). Although there appears to have been no wholesale addition of K20 or Rb to the mineralized area from external sources, these alkalies have been redistributed internally, resulting in patterns of local enrichments and depletions which are characteristic of the mineralized region.Local target anomalies associated with known mineralization consist of CO2/Ca0 > 1.5, As > 10 ppm and K2O > 0. 75%. Not all three values are required to be above these thresholds in order to identify local targets. Combinations such as C02/ Ca0 > 1.5 and As < 10 ppm, CO/CaO 1-1.5 and K20 > 0. 75 or K20 > 0. 75 and As > 10 ppm are equally indicative of proximity to gold occurrences. Gold-bearing veins and associated anomalies occur throughout the entire volcanic succession and are not restricted to any particular stratigraphic horizons. The levels and patterns of alteration and occurrences of gold appear to be structurally controlled."

Jan 1, 1982

By M. D. Aldridge

The results of a two-year research effort aimed at improving communication systems in coal mines is reported. A review of communication methods presently used in coal mines is presented. Theoretical and-experimental results of a four pronged effort in the areas of (1) through-the-earth propagation, (2) paging system design, (3) improvement of wired telephone systems, and (4) carrier current systems are described. Auxiliary systems not included in the above are considered briefly. Various conclusions are drawn in light of practical constraints and the needs of the mining industry. The study clearly demonstrated the need for nine communications to be designed on system basis. The viability of new technology for providing reliable mine communication for improving mine safety and operating efficiency is shown.

Jan 1, 1973

By M. I. Al-Wakeel

Nile sediment was collected as a waste from one of the water treatment plants in Cairo, and subjected to petrographical investigation and granulometric, chemical, and mineralogical analyses. It was expected to find diatomite in that sediment but it was a surprise to find that the diatomite content amounted to about 52.01% by volume in addition to quartz, orthoclase and clay minerals. The latter are represented by montmorillonite and illite minerals. The sediment is light gray in color, soft and has low density and high surface area, such density and surface area generally decrease with temperature. The sediment absorbs 317% of its weight in water. The diatomite skeletons are the main factor responsible for its high porosity producing microporosity and low density, and these particles are concentrated in the very fine silt size fraction (11x2µm). The common diatoms in such sediment include Cyclotella ocellata Pant, and Melosira granulata (Ehr.) Ralfs. It seems that this Nile diatomaceous sediment has many advantages over the fossil diatomite, such as Fayium diatomite in Egypt, with the absence of carbonate minerals that require grinding and calcination those cause destruction of the cellular structure and energy consumption. This Nile diatomaceous sediment can be processed using sequential classification to obtain diatomite concentrate of 88.8% grade at 90.6% recovery, and a middling product of 19.4% grade and 5.8% recovery. The suggested flow sheet is quite simple to produce diatomite product for different industries at a low cost. The unusual particulate structure and chemical inertness make diatomite an ideal mineral to be used as functional filler in a wide range of industries, and as catalyst carriers and insulating material. Key words: Egypt, Nile sediment, Diatomite, Beneficiation, Sedimentation, Classification.

Jan 1, 2008

By Terry J. Close

A mineral resource survey of the 940-square-mile (2,434 km2) Hells Canyon study area, which includes Hells Canyon Wilderness, Snake and Rapid Wild and Scenic River&apos;s, and adjoining roadless lands in Oregon and Idaho, indicates the area is highly mineralized. Thirty-four lode deposits within the study area have resources totaling about 31 million tons (28 million t) containing copper, silver, zinc, gold, and lead; another 42 lodes, not sufficiently exposed to allow resource estimates, are believed to have mineral potential. The most important deposits are copper-, silver-, zinc-, gold-, and lead-bearing volcanogenic occurrences, followed by silver-and copper-bearing contact replacement (tactite) deposits; other lode occurrences are relatively unimportant. The most important placer deposits occur at Dry Diggins; placers along the Snake River are small and scattered. The study area has extensive deposits of limestone and sand and gravel; it has little potential for energy resources.

Jan 1, 1982

By W. R. Reed, D. E. Pollock, T. W. Beck, J. A. Organiscak, J. D. Potts

"In underground continuous mining operations, ventilation, water sprays, and machine-mounted flooded bed scrubbers are the primary means of controlling respirable dust exposures at the working face. Changes in mining arrangements, such as, face ventilation configuration, orientation of crosscuts mined in relation to the section ventilation, and equipment operator positioning, can impact the ability of dust controls to reduce occupational respirable dust exposures. This study reports and analyzes dust concentrations measured by the Office of Mine Safety and Health Research for both remote-controlled continuous mining machine operators and haulage operators at ten U.S. underground mines. Results of these respirable dust surveys show that continuous miner exposures varied little based on depth of cut, but are significantly affected by ventilation configuration. Haulage operators experienced elevated concentrations in blowing face ventilation. The type of cut influenced exposures, with elevated exposures observed for both continuous miner operators and haulage operators when working in crosscuts driven into, or counter to, the section airflow. Individual cuts are highlighted to demonstrate instances of minimal and excessive dust exposure attributable to particular mining configurations. These findings form the basis of recommendations for lowering face worker respirable dust exposures when performing a variety of continuous mining cuts.INTRODUCTION Underground continuous coal mining operations may encounter a wide range of conditions and arrangements during production and development activities. These activities typically produce respirable coal mine dust, putting operators of continuous mining machines and coal haulers at risk for elevated exposures. In order to comply with federal regulations limiting respirable dust exposures for the duration of a working shift, mine operators typically implement ventilation, water sprays, and machine-mounted flooded-bed dust collectors (scrubbers) to dilute and control mine dusts during coal cutting. Nevertheless, changes in operational conditions can limit the ability of these controls to effectively reduce dust exposures. Some examples of conditions that can change during the course of mining include face ventilation configuration, orientation of crosscuts mined in relation to the section ventilation, and operator positioning. Because these arrangements are largely under the control of mine operators, any insight into associated exposures may inform future plans and behaviors, reducing occupational exposures to respirable dust. The objective of this OMSHR study is to evaluate respirable dust exposures associated with a range of continuous mining arrangements by comparing occupational dust concentrations measured during a series of field surveys. These comparisons consider face ventilation configurations, depths of cut, and crosscut mining practices."

Jan 1, 2015

By Thornton L. Neathery

Vertical magnetic surveys have been made over about 3, 150 miles of the crystalline area of east-central Alabama. A contour map (100-gamma interval) showing regional magnetic anomalies has been prepared (scale 1:250,000) from data points located at quarter-mile intervals on all public roads. Small one- and two-station anomalies were eliminated, leaving only areally extensive anomaly features associated with regional geology. The regional gradient was "filtered" from the basic data and the resulting magnetic configuration compared to the regional geology. Regional lines of vertical magnetic intensity trend northeast and follow the structural framework of the area. Correlations can be made between a large number of geologic and magnetic features. The strongest regional anomalies are associated with the Goat Rock, Bartletts Ferry, Towaliga, and Brevard fault structures. The Inner Piedmont area is characterized by a broad regional high. The magnetic values of the northern Alabama Piedmont grades gently northwestward, disrupted occasionally by elongate highs and lows associated with amphibolites or granites. Scattered throughout the Piedmont are anomalous areas of high magnetic intensity; some are related to magnetic-bearing rocks, and some Indicate possible mineralization. Most of the anomalies have not been evaluated,

Jan 1, 1972

Coal, America&apos;s most abundant fossil fuel, is expected to play a key role in our pursuit of energy independence. A substantial increase in coal exploitation will be required if we are to fulfill our future energy needs. It is essential that new developments continue if stable coal prices are to be achieved and maintained. The challenge of the mining industry is to continue these developments in the face of problems related to increasing labor costs, inflation and environmental restoration. With expectations of increased activity in surface coal mining, the U.S. Bureau of Mines has authorized this study to determine the preliminary economic and technologic feasibility of underspoil haulage in area strip coal mines and to identify geologic and geographic areas where such a system could be used. These objectives were met by literature search, data-gathering visits to several active area strip mines and by analyzing various haulage systems that were superimposed on three model mines. Potential advantages of such a system include: 1) improved mine design; 2) lower mine operating costs; 3) improved land reclamation; 4) lower manpower requirements; 5) lower mobile equipment requirements; and 6) smaller, less sophisticated maintenance facilities.

Jan 1, 1975

By Sheridan J. Rodgers

Toxic fumes generated during shot firing were measured in a phosphate rock mine and a copper mine. Fumes generated during firing of explosives in the Bureau of Mines 1350 ft3 test chamber were measured also. The release of fumes from water gels, ammonium-nitrate oil mixtures and nitroglycerin based explosives was studied. Direct reading instruments were used to monitor the fume concentrations. The amount of CO produced per unit weight of nitroglycerin explosives (0.41 ft3/200 grams) was higher than that produced by ammoniumnitrate-oil mixtures (0.24 ft3/200 grams) and water gels (0.16 ft3/200 grams). The amount of NOx produced by nitroglycerin based explosives was also higher than the amount produced by water gels or ammonium nitrate-oil mixtures.

Jan 1, 1976

By B. Hines

Grinding efficiency in a vertical stirred mill is affected by a wide range of process and mill configuration variables. Of these, the media fill, size, and intrinsic density have a significant effect on power draw and grinding performance. Media-related factors that influence grinding performance include, e.g.,a higher media filling providing additional particle breakage sites, or a lower bead density decreasing the running torque at a given media filling. It has been estimated that the grinding media can cause up to a 30% change in the specific energy required to grind. FLSmidth has generally recommended that the intrinsic density (specific gravity) of the grinding media be more than triple the slurry density. This density difference helps to ensure that sufficient stress intensity is generated in the mill to provide particle breakage. It also reduces the chance of media ?float? if there is a spike in either slurry density or slurry flow rate. The VXPmills have historically operated at slurry density values between 1.2 and 1.5 kg/L, which translates to nominal bead intrinsic density range between 3.6 and 4.5 kg/L. The current trend towards regrinding bulk flotation concentrates to even finer sizes, to improve recoveries of fine grained minerals, has provided motivation to consider closed-circuit operation of stirred media mills. The slurry density in this application is typically higher than in open-circuit operation due to the higher percent solids in cyclone underflows. An additional effect is that closed-circuit operation increases the potential for media float due to higher flow rates as slurry is recycled to the mill. The normal progression in extending the operating range of existing equipment is to carry out laboratory testing before pilot-scale and plant-scale trials. The results presented in this paper examine the media density to slurry density ratio and its effect on grinding performance.

Feb 23, 2014

Low-cost housing, like automobiles, should be appraised in the light not merely of first cost but of upkeep as well. Even more important than the number of miles the family car will go on a gallon of gasoline is the number of days the family home can be kept comfortable on a ton of fuel. A furnace tender who tossed every third shovelful of coal into the ashcan would lose his job promptly, but the effect is the same when homes continue year after year to pour out precious heat through uninsulated roofs and walls, Greater economy in household heating means even more to the national economy than to the individual, especially now that we are preparing for defense. Our fuel resources, although large, should be conserved. If less fuel is used for civilian needs, augmented requirements for defense can be met without unduly increasing the number of men needed at the coal mines and oil ells or adding new producing units that might complicate ultimate readjustment to peacetime conditions when the emergency is past and over-expansion of many industries brings new problems if unnecessary demands for transportation facilities are reduced, public carriers will be able to haul more munitions, and manpower needed for national defense will be released; and by protecting workers from health hazards in their homes additional man-hours of productive effort will be gained. Moreover, reducing the running expenses of houses by proper heat insulation helps home owners to maintain payments on property, and by minimizing foreclosures helps to stabilize the financial structure of the country. In short, here is a situation where the interests of the individual and the Nation are identical and the greatest good for the greatest number is obtained without sacrifice to anyone.

Jan 1, 1941

By G. S. Hume

Introduction Core drilling of the bituminous sands of northern Alberta has been carried on by the Mines and Geology Branch, Department of Mines and Resources, under the supervision of the Director, W. B. Timm. This was part of the Dominion Government&apos;s wartime investigations, which included an agreement with Abasand Oils, Limited, for the study of commercial possibilities of obtaining oil from the bituminous sands. The drilling programme, commenced in 1942 by the Consolidated Mining and Smelting Company of Canada, was continued in 1943 and subsequently by Boyles Bros. under contract with the Mines and Geology Branch. Several areas have been investigated and one of these, the Mildred-Ruth Lakes area, &apos; herein described, is of special importance in that it contains a sufficiently rich and large deposit of bituminous sands and bitumen beds to warrant consideration of commercial developments for the production of oil. The Steepbank Area, East Side of Athabaska River The Steepbank area, on the east side of Athabaska river in township 92, about twenty-two miles north of Fort McMurray, was selected for drilling in 1942 because previous investigations by Ells indicated it was one of considerable promise both from the standpoint of having reasonably rich bituminous sands under relatively light overburden and also having an excellent tailing disposal and plant site for large-scale operations in proximity to Athabaska river. The drilling done in 1942 and 1943 was largely exploratory, and, when it was found that the southerly part of township 92 had only low-grade material, closer drilling was done in 1944-45 in the richer, more northerly part.

Jan 1, 1947

By R. E. Zimmerman

Wide attention is being placed upon various methods for cleaning the fine sizes of bituminous coals. The author describes and analyzes the results achieved on wet concentrating .tables of modern design on unclassified feeds of - 1/2 in. particle sizes, including tests on high-sulphur coals.

Jan 1, 1950