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By Bruno Lebon, Koulis Pericleous, Georgi Djambazov, Mayur Patel

"High speed compressible jets are used in a number of steel-making applications. In the case of the BOF, a compressible oxygen jet reacts with a carbon-rich iron bath to reduce carbon levels and produce steel. The intensity of the process is governed by the speed of the jet and by the size and shape of the depression created in the metal and slag by the force of the jet, i.e. by the corresponding free surface. This is a difficult CFD problem, since there are compressible and incompressible regions in the flow domain, which need to be handled differently in a finite-volume (FV) pressure-correction scheme. Also, standard turbulence models do not account for compressibility, or the large difference in density between the cold oxygen jet and the hot reacting surroundings. Corrections are introduced to the k-E model to remedy this deficiency and the results are validated against experimental data. The compressible/incompressible boundary is handled through a transition region, based on Mach number.IntroductionThe deformation of a free surface by a compressible high speed jet is of paramount engineering interest, particularly for understanding the physical processes within a Basic Oxygen Furnace (BOF). In a BOF, a supersonic oxygen jet impinges on a molten iron surface, thereby creating a cavity. Oxygen penetrates the bath and removes carbon, resulting in low carbon steel [1].The challenges in modelling such a process lie in coupling a solution domain with distinct compressible and incompressible regions and in dealing with large density differences between the modelled gas and liquid. The modelling of compressibility within the jet is crucial, since the correct velocity profile in the jet is required to determine the cavity depth with accuracy."

Jan 1, 2012

By William Gleason

From Nov. 16-20, the Extraction 2025 Conference will be presented in Phoenix, AZ. The unique conference brings together the 12th International Copper Conference, the 6th International Symposium on Nickel and Cobalt as well as cross-cutting symposia. Extraction 2025 is co-organized by The Metallurgy and Materials Society (MetSoc) of the Canadian Institute of Mining, Metallurgy and Petroleum (CIM), the Society for Mining, Metallurgy & Exploration (SME) and The Minerals, Metals & Materials Society (TMS). The previous, and first Extraction meeting (Extraction 2018) was held jointly by these three societies seven years ago in Ottawa and was a huge success with more than 90 percent of respondents indicating interest in attending a future event. Kimberly Mills, senior process engineer at Samuel Engineering, is the lead for SME. “This installment of Extraction is featuring Copper 2025, Nickel-Cobalt 2025 as well as crosscutting symposia,” said Mills. “All three societies participate on the International Organizing Committee for the Copper Conference Series and are well situated to host this event together. TMS is also hosting the Ni-Co conference this year and agreed to include it as part of Extraction. There are many aspects that can be shared between these commodities to share information on processing technologies and to learn from each other.” SME is the overall conference chair and running the logistical aspects of the event, which includes managing all aspects of the venue and the registration system as well as tours and short courses, Mills said. “SME has many dedicated members serving in various capacities on organizing and programming committees, including Nick Gow serving as Technical Committee Co-Chair for Copper and Adam House assisting on the Copper IOC.” When Extraction 2025 kicks off, it will be focused on the metals needed for the global energy transition with a special focus on copper and nickel-cobalt. “With as rapidly as the industry is changing and the huge demands for these metals we have some serious challenges ahead of us,” Mills explained. “These challenges require collaboration, creative solutions and engaging experts, both inside and outside of our fields, with a push for sustainable sourcing, ethical supply chains, environmental and social responsibility.” The International Copper Conference was started in 1987 as a collaboration between the Institute of Mining Engineers of Chile (IIMCH) and MetSoc of the CIM. The event is typically held every four years and has always been held as a standalone or headlining event at a society annual meeting, said Mills. “Over the years, this conference series alone has brought together members of IIMCH, MetSoc, TMS, SME, the Society for Metallurgists and Miners from Germany (GDMB), the Mining and Materials Processing Institute of Japan (MMIJ), the South African Institute of Mining and Metallurgy (SAIMM) and the Nonferrous Metals Society of China (NFSOC),” she added. “Being a part of Extraction allows for even more sharing of ideas and expansion of networking. This conference has not been held in the United

Oct 1, 2025

By M. M. Botz, F. W. DeVries

Discussion by F.W. DeVries Comments on natural cyanide attenuation. The paper by Botz and Mudder in the November 2000 issue of Minerals and Metallurgical Processing had one disappointing aspect. Table 1 (p. 229) failed to include a significant species - neutral copper cyanide (CuCN). This compound has been most trouble-some in many plant-scale cyanide cleanup processes, includ- ing acidification-volatilization- reneutralization (AVR), hy- drogen peroxide cleanup and air/SO2 cleanup. It has also plagued many pilot efforts to use ion-exchange (IX) resin technology. This author elucidated the concept that, under some conditions, copper cyanide failed to precipitate out of treated effluents and appeared to exist as a filterable colloid that reported as copper and cyanide, with the latter measured as WAD (weak-acid-dissociable) cyanide in that analytical method. The concentrations measured were very near the levels of 0.2 ppm, often the regulatory limit for WAD cyanide. The copper concentration, using the 1 : 1 ratio for this com- pound, would then be more than 0.4 ppm, which could also be unacceptable. We discovered that it was unsafe to assume that the Cu(CN),- would surrender both cyanide ions simultaneously and allow cupric copper to be removed subsequently as, say, cupric ferrocyanide (Hatchett's Brown). This compound could be ignored as safely as the "iron blues," as essentially an inert solid, stable in geologic time if not exposed to sunlight. Under poorly controlled oxidation of the cyanocuprite ions (copper with four, three or two cyanides complexed to the copper), CuCN could well be formed and could not be assumed to precipitate out as a solid. The authors of the paper, by failing to include the CuCN species in their model, may have left users of the model prone to ignore the possible occurrence of the colloidal(?) form in the discharge, thus finding an effluent that failed to meet regulatory limits. (See addendum below.) This somewhat ephemeral material may well have been responsible for some large-scale failures of cyanide destruction technology to succeed at sites in North America and elsewhere. Two specific references alluding to this occurrence may be found: Griffiths et al., 1987, "The detoxification of gold-mill tailings with hydrogen peroxide," Journal of the South African Institute of Mining and Metallurgy, September, p. 282. DeVries, 1989, "Improved understanding in detoxification of cyanide leach liquors using peroxide" Rand01 Gold Conference, Sacramento CA, p. 15 1. It is advisable for workers in this area of cyanide removal or recycle to avoid assuming that CuCN will, with certainty, precipitate out of solution, or that the dicyanocuprite ion will part simultaneously with both cyanide ions and allow cupric copper to be dealt with by other reactions. One further piece of work may be incomplete. That is, a definitive study of the long-term behavior of CuCN that does precipitate when exposed to other compounds present in neutralized tailings. Addendum. The extremely complex reaction of cupric ion on cyanide- which, of course, results in oxidation of cyanide to cyanate, probably through the intermediate stage of forming cyanogen [(CN)2] from oxidation of HCN with its hydrolysis to cyanate and cyanide ion - involves two cyanide moieties and the reduction of the cupric ion back again to the cuprous state. This, then, can form the CuCN potential "solid" that was already the undesirable species. In cyanide cleanup, with either air/SO2 or hydrogen peroxide, copper is generally employed as the catalyst, so it is unclear what happens when the CU(CN)2-1 is ultimately exhausted. Certainly, the field evidence is quite clear that all

Jan 1, 2002

By Baafi E. Y

Dragline monitoring systems are normally the best tool used to collect data on the machine performance and operational parameters of a dragline operation. This paper discusses results of a time study using data from a dragline monitoring syste

Jan 1, 1998

By Anthony T. Iannacchione

The Solar No. 7 and Solar No. 10 mines were designed to prevent mine waters from directly discharging to the surface. In January of 2004, a discharge occurred as the Solar No. 7 mine was in its final stage of flooding through a barrier averaging 456-ft in width over a 1,600-ft length (No. 1). Another barrier (No. 2) was designed to protect four municipal water wells operating 1,800- ft away and producing from within or slightly below the Upper Kittanning coalbed from the adjacent Solar No. 7 and No. 10 mine pools. These two barriers were selected for this study because of varied mine layouts, mining methods, and geology factors affecting their performance. Analysis was aided by the collection and georeferencing of 6-month mining maps from the Pennsylvania Department of Environmental Protection (PA DEP). A structure contour map of the Upper Kittanning coalbed was constructed from mine map elevation points. These data and 2-ft surface contour maps were used to measure the precise location of the coal outcrop. The actual discharge point was as little as 425-ft away from a thinpillar section and 475-ft away from a pillar recovery section. The discharge point was found to be located slightly above the coal, indicating that the drainage path was at least partially through the strata directly above the Upper Kittanning coalbed. Hydraulic conductivities and potential discharge pathways are analyzed and discussed. The possible factors influencing the performance of the down-dip barriers at Solar No. 7 and Solar No. 10 are: a) the width of the barrier, b) the applied hydraulic gradient, c) the type of mining adjacent to the barrier, d) the overburden, e) the pattern and characteristics of fractures, and f) the quality of waters contained within the mine pools. This study, part of a larger effort funded by the Appalachian Research Initiative for Environmental Sciences (ARIES), is tasked to determine the key factors responsible for the successful design of down-dip coal barriers.

Jan 1, 2013

By C. O. Dale, W. J. Rundle

THE upper Mississippi Valley zinc-lead area was the first major lead-producing section in the United States. The lead ore, found near the surface in crevices, was relatively pure galena that could be smelted directly into lead, at first in log hearth furnaces and later in more efficient blast type furnaces. French Canadian fur traders encouraged the Indians to mine the lead ore and showed them how to smelt it into lead that had a high value for bullets1 Nicholas Perrot found lead ore on the Mississippi River bluffs near the junction of Wisconsin and Illinois and in 1690 established a trading post on the Wisconsin side of the river opposite the present site of Dubuque, Iowa.2 Shortly after 1720 discovery of Mine La Mott in Missouri diverted considerable attention from the Upper Mississippi area. Mining continued on a desultory basis with operations concentrated in the Galena, Illinois-Dubuque, area. In 1740 at least 20 miners were at work in the Fever River area around Galena and are reported to have shipped 2500 70-lb pigs of lead to Kaskaskia in 1741." Julien Dubuque established a mining and smelting operation in 1790 near the city that bears his name and was granted sole right to exploit the mining operations on the lands of the Sauk and the Fox Indians. He is reported to have produced 30,000 70-lb pigs of lead in 1805. Following the death of Dubuque in 1810 the Indians refused to let the white miners enter their lands, and little was done on the Iowa side of the river until the Indians were removed by treaty with the United States government in 1832." Early mining was entirely for lead but as the crevices were followed down, increasing percentages of zinc sulphide and zinc carbonate were encountered and at first discarded. Later a market became available for the zinc ores, and hand jigging devices were made to separate the lead, the zinc, and the rock or waste materials. The first record of zinc production from the area is for 1860. Production of zinc passed that of lead before 1900, reached a peak of 64,000 short tons in 1917, fell off rapidly and continually to about 2000 short tons in 1938, and since 1940 has ranged from 11,000 to 19,000 short tons. Lead has been of considerably less importance since 1900, and at present only about 10 pct as much lead as zinc is produced. Practically all of the zinc ore has come from orebodies that are rather flat and wide with considerable length as compared to width. Most of the early lead came from the crevice type deposit, but present production is from the predominately flat zinc orebodies. The Graham-Snyder orebody, scene of Eagle Picher operations, is practically all zinc with little or no lead being recovered. Marcasite, present in varying amounts, makes production of finished concentrates by gravity separation impractical. Satisfactory lead and zinc concentrates have been produced since flotation was introduced in the area in 1927. An acid recovery plant was operated for about 20 years after World War I, but it has been dismantled, and no recovery of the iron sulphides in the ores of the district is being made at the present time. In June 1950 there were three companies operating mines and mills, Tri-State Zinc Co., Calumet & Hecla Consolidated Copper Co., and Eagle Picher Mining and Smelting Co. The Vinegar Hill Zinc Co. had completed a shaft at a new orebody and had started to develop the mine which will supply the Cuba City mill. The Cuba Mining Co. was holding the Andrews Mine inactive. The Dodgeville Mining Co. was not operating but was exploring for additional reserves. Several small mines were selling ore to the Eagle Picher mill. A general area map is given in Fig. 1. The Eagle Picher Mining and Smelting Co. entered the area in 1946 with an active exploration campaign. Leases on a block basis were secured for the area south from the Wisconsin-Illinois line near

Jan 1, 1953

By C. O. Dale, W. J. Rundle

THE upper Mississippi Valley zinc-lead area was the first major lead-producing section in the United States. The lead ore, found near the surface in crevices, was relatively pure galena that could be smelted directly into lead, at first in log hearth furnaces and later in more efficient blast type furnaces. French Canadian fur traders encouraged the Indians to mine the lead ore and showed them how to smelt it into lead that had a high value for bullets1 Nicholas Perrot found lead ore on the Mississippi River bluffs near the junction of Wisconsin and Illinois and in 1690 established a trading post on the Wisconsin side of the river opposite the present site of Dubuque, Iowa.2 Shortly after 1720 discovery of Mine La Mott in Missouri diverted considerable attention from the Upper Mississippi area. Mining continued on a desultory basis with operations concentrated in the Galena, Illinois-Dubuque, area. In 1740 at least 20 miners were at work in the Fever River area around Galena and are reported to have shipped 2500 70-lb pigs of lead to Kaskaskia in 1741." Julien Dubuque established a mining and smelting operation in 1790 near the city that bears his name and was granted sole right to exploit the mining operations on the lands of the Sauk and the Fox Indians. He is reported to have produced 30,000 70-lb pigs of lead in 1805. Following the death of Dubuque in 1810 the Indians refused to let the white miners enter their lands, and little was done on the Iowa side of the river until the Indians were removed by treaty with the United States government in 1832." Early mining was entirely for lead but as the crevices were followed down, increasing percentages of zinc sulphide and zinc carbonate were encountered and at first discarded. Later a market became available for the zinc ores, and hand jigging devices were made to separate the lead, the zinc, and the rock or waste materials. The first record of zinc production from the area is for 1860. Production of zinc passed that of lead before 1900, reached a peak of 64,000 short tons in 1917, fell off rapidly and continually to about 2000 short tons in 1938, and since 1940 has ranged from 11,000 to 19,000 short tons. Lead has been of considerably less importance since 1900, and at present only about 10 pct as much lead as zinc is produced. Practically all of the zinc ore has come from orebodies that are rather flat and wide with considerable length as compared to width. Most of the early lead came from the crevice type deposit, but present production is from the predominately flat zinc orebodies. The Graham-Snyder orebody, scene of Eagle Picher operations, is practically all zinc with little or no lead being recovered. Marcasite, present in varying amounts, makes production of finished concentrates by gravity separation impractical. Satisfactory lead and zinc concentrates have been produced since flotation was introduced in the area in 1927. An acid recovery plant was operated for about 20 years after World War I, but it has been dismantled, and no recovery of the iron sulphides in the ores of the district is being made at the present time. In June 1950 there were three companies operating mines and mills, Tri-State Zinc Co., Calumet & Hecla Consolidated Copper Co., and Eagle Picher Mining and Smelting Co. The Vinegar Hill Zinc Co. had completed a shaft at a new orebody and had started to develop the mine which will supply the Cuba City mill. The Cuba Mining Co. was holding the Andrews Mine inactive. The Dodgeville Mining Co. was not operating but was exploring for additional reserves. Several small mines were selling ore to the Eagle Picher mill. A general area map is given in Fig. 1. The Eagle Picher Mining and Smelting Co. entered the area in 1946 with an active exploration campaign. Leases on a block basis were secured for the area south from the Wisconsin-Illinois line near

Jan 1, 1953

By Edgar O. McAlister

Associated with cordilleran intrusives of intemediate to acidic composition, gold/silver ores are generally found in the intruded host rocks which are adjacent to these intrusives. Generally precious metal deposits lie further from the intrusives than allied base metal deposits. For vented intrusives, the associated volcanics may constitute the intruded rock and form the host for precious metal accumulation. Potential field methods, particularly magnetics, can help to define unseen boundaries of intrusive systems and thus can point to generalized prospecting targets. Other clues arise from the intrusive system type, its emplacement fracturing, the host rock type and local magnetic changes caused by mineralization processes.

Jan 1, 1984

By C. R. Stelck

"AbstractThe Cardium formation of northeastern British •Columbia •contains an erosional unconformity that becomes progressively more severe northward until, •at Liard river, the stratigraphic hiatus eliminates the underlying Lower •Cardium sandstone, the Kaskapau formation, and the upper Dunvegan sandstones. The area of unconformity roughly coincides with the distribution of the continental facies of the earlier Dunvegan formation. Along Wapiti river, the zone fossil Scaphites ventricosus Meek and Hayden is found in the Bad-heart member of the overlying Wapiabi shale; Scaphites :preventricosus. Cobban marks the base of the Wapiabi shale; Scaphites cf. corvensis •Cobban is found in the middle shale member of the •Cardium formation. The log of the Red-Willow No. 1 well shows close similarity to the outcrop sections south of Wapiti river. The Cardium formation is mainly late Turonian in age. Two other pre-Cardium Turonian sands of north-eastern British Columbia are named the Wartenbe and Tuskoola sands.IntroductionTHE Upper Cretaceous Cardium (Bighorn) sandstone formation of the Foothills of northeastern British Columbia carries within its formational limits an erosional unconformity. The unconformity decreases to the southeast, becoming in immediate shoreline regions, now under the plains, a minor diastem. Such diastems, or stratigraphic intervals of non-deposition, occurring in the shallow unda-zone are paralleled in the deeper portions of the unda-zone by the phenomena of sub-aqueous winnowing. '.This winnowing and re-working •at critical depths creates sand areas with porosity."

Jan 1, 1955

By G. W. Healy

Activities of oxides in the ternary FeO-MnO-SiO system are calculated from data on the binaries, using the Gibbs -Schuhmann method. These activity data are used, together with thermodynamic relations, to calculate the contents of oxygen, silicon, and manganese in liquid iron, and the composition of the corresponding oxide phases in equilibrium with it. Excellent agreement was found between calculated and experimental metal compositions, indicating that thermodynamic methods, such as those presented, can supply useful data on slag-metal equilibria, and are therefore capable of wider application. When molten steel containing oxygen is treated with a deoxidizer, the product of the reaction is composed of the oxides of the deoxidizing elements together with more or less iron oxide. This assemblage of oxides is presumably very close to equilibrium with the melt since it is formed directly from elements dissolved in it. Therefore, it is likely that metal analyses corresponding to a given oxide phase composition are calculable with considerable precision where sufficient information is available on activities in both phases. The present study was made to test this hypothesis in the case of deoxidation by silicon and manganese. Here experimental data on the relationship among oxygen, silicon, and manganese in the metal phase are available, as are activity data for the MnO-SiO2, FeO-SiO2, and FeO-MnO binary systems. A further objective was to demonstrate in a specific example how gaps in the data may be filled by judicious interpolation, and how the Gibbs-Schuhmann method is applied to obtain activities in ternary systems. The rigorous derivation of the latter, requiring considerable facility in handling partial differential equations, tends to mask the real simplicity of the method, and repel the very engineers and experimenters who would benefit the most from its use. I) GENERAL PROCEDURE Deoxidation of steel with silicon and manganese results in the formation of two phases, metal and oxide. The number of components is four—Fe, Mn, Si, and 0. The phase rule then gives the number of degrees of freedom: If temperature and pressure are fixed, 2 deg of freedom remain. Consequently, it suffices to fix the concentration of two of the components of the system for all the concentrations to be determined and, at least in principle, calculable. The practical problem is then to discover a straightforward method of calculation with a minimum of trial and error solutions. The type of reactions to be dealt with are like the following: Si (in steel) + 2 O(in steel) = SiO2(in oxide phase) The standard free energy of this reaction is readily obtained from the literature, so that the equilibrium constant can be calculated by the expression: Since the metallurgist is concerned with percentages rather than activities, a real solution requires information that will permit activities to be converted to concentrations. This information is fairly adequate for the elements dissolved in molten steel, but is not available for the FeO-MnO-SiO2 oxide system. Therefore, the first step in this study was to find the relation between activity and concentration for the three oxides making up the system. The next step was the calculation of slag and metal compositions that are in equilibrium with one another. As shown by the phase rule, it is sufficient to assume the values of two composition variables in order to calculate the rest. But which two are picked makes a vast difference in how difficult the calculation turns out to be, so that it is necessary to make preliminary trial of several routes to find the easiest one. A convenient method is to begin with the slag, and to pick FeO concentration and that of one of the other oxides. Starting with the relation between oxygen dissolved in the liquid steel and FeO in the slag permits a good first estimate to be made of the oxygen content of the steel in equilibrium with FeO, because the iron content being fairly close to 100 pct, Fe has an activity close to unity. Using this first estimate of oxygen activity, approximate values of the manganese and silicon contents of the melt are readily calculated from the appropriate equilibrium constants. A minor correction for the depar-

Jan 1, 1963

President AIRS. THOMAS T. READ 9 Windmill Lane Scarsdale, N. Y. First Vice-President AIRS. THORNE E. LLOYD 14 Green Hill Road Morristown, N. J. Second Vice President MRS. FRED SEARLS. JR. 1 Gracie Square New York. N. Y. Third Vice-President, MRS. WARREN J. MEAD 88 Rutledge Rd. Belmont Mass. Fourth Vice-President MRS. EDWIN LETTS OLIVER 60 King Avenue Piedmont, Calif.

Jan 1, 1943

By Alex C. Smith

The National Institute for Occupational Safety and Health (NIOSH) and Northwest Barricade LLC (NWB) conducted a study to evaluate the effectiveness of a novel fire blocking gel for use in underground coal mines to extinguish or to retard the growth of a coal fire. The gel agent was subjected to controlled laboratory testing to assess its ability to delay coal ignition. It was then evaluated to determine if manual fire hose application could be used to apply the agent to mine roofs and ribs to provide a safe egress for mine rescue teams from a fire area. The gel agent was also evaluated in a water sprinkler system to determine its potential for use in conveyor belt fire suppression systems. The agent was then tested in live-fire exercises to examine its effectiveness in retarding and extinguishing a deep-seated coal fire and wood fire. Lastly, the ability of a Mine Rescue Team to quickly and safely apply the gel agent to a mine entry during a simulated mine fire exercise was determined.

Jan 1, 2010

By H. Polat, Q. Hu, M. Polat, S. Chander

"The electrostatic charge on spray droplets of ionic surfactant solutions and coal particles was measured and the results were correlated with the dust collection efficiency. When various surfactant were added, the magnitude of the droplet charge increased significantly and it was observed to be a function of surfactant type and concentration. The concentration of maximum droplet charge coincided with surfactant concentration where maximum collection efficiency was observed for these surfactants. Particles of coal also carried substantial amount of charge magnitude of which seemed to be a function of coal rank.Based on the results presented in this paper, it was concluded that ionic surfactant primarily act as a strong electrostatic charge inducer for droplets. Due to interactions between these highly charged droplets and naturally charged particles, the efficiency of droplet-particle collisions play a primary role when compared to the wetting and engulfment phenomenon which could only follow a successful collision. INTRODUCTIONWater spray are widely used to suppress airborne dust in mine atmospheres (Walton and Woolcock, 1960; Kobrick, 1970; Hamilton, 1974; Jayaraman et al., 1986). Several investigators have considered the use of surfactants to enhance the effectiveness of water sprays especially for difficult to wet particles such as those of coal (Glanville and Wightman, 1979). The capture of dust particles by water droplets involves droplet-particle collisions, adhesion of particles to droplets, and engulfment of particles into droplets. Surfactants affect these sub processes through their influence on droplet charge, surface tension, and wetting. The last two mechanism have been thoroughly studied in recent years (Walker et al., 1952; Cohen and Rosen, 1981; Glenville and Haley, 1982; Chander et al., 1988; 1991). However, little attention has been paid to the role of electrical charge on particles and droplets on the collision and adhesion of spray droplets and dust particles."

Nov 1, 1995

By Rose W. J

Geophysical prospecting was first recognized in Australia as an important aid to mining enterprises in 1927, when, on the suggestion of Sir Herbert Gepp, the "Imperial Geophysical Experimental Survey" was organized. The function of this survey was to carry out investigations on the applicability and efficacy of the most important geophysical methods under Australian conditions. The survey was formed under the joint auspices of the British Empire Marketing Board and Australian Commonwealth Government, and the investigations were carried out in Australia under the leadership of Mr. A. Broughton Edge, B.Sc., A.R.S.M., F.G.S., M.Inst.M.M., during the years 1928 and 1929. A description of the work performed, the apparatus used, the principles of the methods, and the results and conclusions of the survey are included in a report published by the Cambridge University Press in 1931.In 1932 Sir Herbert Gepp became interested in some gold mines in Eastern Victoria, in the Cassilis and Bethanga districts, and realizing that the lodes in these areas would be favorabIe for a geophysical examination, he arranged for a series of tests to be carried out. This work was performed by Mr. E. L. Blazey, B.E.E., a former member of the staff of the Imperial Geophysical Experimental, Survey, under the general direction of, and in consultation with, Mr. W. J. Rose, B.M.E.The work was commenced in October, 1932, at Cassilis, Vie., continued at Talgarno, Vie., .and concluded at...

Jan 1, 1933

By Kai Koosmen, Mehdi Serati, Tengzhou Wang

Spalling and rockburst are unwanted brittle failures at the boundaries of underground excavations that are commonly observed in hard rock and high-stress environments at significant depths, although, spalling has also been observed in comparatively shallow soft rocks. The crack initiation (CI) stress threshold (representing the stress level at which new micro cracks begin to form in an intact rock) is widely used to establish the in-situ spalling strength, and is generally regarded as the lower limit of the long-term rock strength. This study analyses the evolution of CI and other mechanical properties for a high-porosity sandstone with an average UCS of 38 MPa under unconfined cyclic compressive loading. The results indicate that rock properties are variably affected by cyclic loading with; no significant effect on Youngs Modulus; a moderate increase in Poisson’s ratio and fracture angle; a moderate decrease in UCS; and a major reduction in the CI stress threshold. All of these changes were generally amplified by cyclic loading at higher stresses. From the results, it is concluded that rockburst and spalling limit in underground structures may reduce over time if the rock is subject to repetitive cyclic loading, and that the reductions will be greater for higher cyclic stresses. This may be a significant factor in the design and operation of some deep underground structures.

Apr 26, 2022

By William H. Spice

The year 1942 in the South Central Texas area was marked by a sharp curtailment of exploratory drilling as compared with the past several years. In the 33 counties that compose this district, 17 of which are nonproducing counties, only 51 exploratory wells were drilled during the year 1942. This compares with 118 exploratory wells drilled during 1941, or a decrease of more than 50 per cent. At the end of the year 10 active exploratory wells were drilling in this area, as against 19 being drilled at the end of 1941. Of the exploratory wells drilled, two brought in oil wells and were new field discoveries and one was a gas well extending a recently discovered shallow gas area in the western part of the district. This compares with five new oil fields, one new . gas field and two extension wells drilled in 1941. Both new field discoveries were small and in areas outside of the general trend of the main producing horizon of the district in Edwards limestone: One new field, the Imogene, in Atascosa County, is a deep Edwards limestone prospect at 7500 ft., and the other new field, the Poth, in Wilson County, is a sSEa110w Wilcox (Eocene) prospect at 4000 ft. Subsequent drilling in each field to the end of I942 has proved disappointing. There were no new discoveries along the old Balcones fault-line trend, although 35 of the exploratory wells were drilled in counties along this trend. Approximately 38 wells were drilled in or adjacent to the proven fields of the district, of which 18 were oil wells, 2 were gas wells and 17 were dry holes. The district produced 6,186,178 bbl. of oil during 1942, which was a 7 per cent decrease under production for 1941. Approximately 4,961,000 bbl. of this total production, a slight increase over 1941, was produced by the four Edwards-limestone fields, Luling, Branyon, Salt Flat and Darst Creek, and the rest of the production came from the other 42 active fields in the district. During the year, 20 new producing wells were completed and 221 wells were abandoned in the producing fields. This alarming excess rate of abandonment~ over completions will be further reflected undoubtedly by a further decreased rate of 1943 production under 1942. Two active fields in the district in which more than one producing well was completed during the year were Bee Creek and Washburn. The majority of exploratory work in the district was confined to areas along the Wilcox trend, with a certain amount in progress along the deeper Edwards limestone trend. The successful completion of sevemi wells in the Washburn field from multiple sands in the Lower Wilcor (Eocene) has stimulated exploratory work along this trend, while the completion of a small well in the Imogene field from the Edwards limestone at 7500 ft. has renewed interest in this horizon at depths greater than generally are producing in the district. New Fields ounty. ble Oil and Refining Company's No. I

Jan 1, 1943

By William H. Spice

The year 1942 in the South Central Texas area was marked by a sharp curtailment of exploratory drilling as compared with the past several years. In the 33 counties that compose this district, 17 of which are nonproducing counties, only 51 exploratory wells were drilled during the year 1942. This compares with 118 exploratory wells drilled during 1941, or a decrease of more than 50 per cent. At the end of the year 10 active exploratory wells were drilling in this area, as against 19 being drilled at the end of 1941. Of the exploratory wells drilled, two brought in oil wells and were new field discoveries and one was a gas well extending a recently discovered shallow gas area in the western part of the district. This compares with five new oil fields, one new . gas field and two extension wells drilled in 1941. Both new field discoveries were small and in areas outside of the general trend of the main producing horizon of the district in Edwards limestone: One new field, the Imogene, in Atascosa County, is a deep Edwards limestone prospect at 7500 ft., and the other new field, the Poth, in Wilson County, is a sSEa110w Wilcox (Eocene) prospect at 4000 ft. Subsequent drilling in each field to the end of I942 has proved disappointing. There were no new discoveries along the old Balcones fault-line trend, although 35 of the exploratory wells were drilled in counties along this trend. Approximately 38 wells were drilled in or adjacent to the proven fields of the district, of which 18 were oil wells, 2 were gas wells and 17 were dry holes. The district produced 6,186,178 bbl. of oil during 1942, which was a 7 per cent decrease under production for 1941. Approximately 4,961,000 bbl. of this total production, a slight increase over 1941, was produced by the four Edwards-limestone fields, Luling, Branyon, Salt Flat and Darst Creek, and the rest of the production came from the other 42 active fields in the district. During the year, 20 new producing wells were completed and 221 wells were abandoned in the producing fields. This alarming excess rate of abandonment~ over completions will be further reflected undoubtedly by a further decreased rate of 1943 production under 1942. Two active fields in the district in which more than one producing well was completed during the year were Bee Creek and Washburn. The majority of exploratory work in the district was confined to areas along the Wilcox trend, with a certain amount in progress along the deeper Edwards limestone trend. The successful completion of sevemi wells in the Washburn field from multiple sands in the Lower Wilcor (Eocene) has stimulated exploratory work along this trend, while the completion of a small well in the Imogene field from the Edwards limestone at 7500 ft. has renewed interest in this horizon at depths greater than generally are producing in the district. New Fields ounty. ble Oil and Refining Company's No. I

Jan 1, 1943

By John J. Reed

The 1945 fire at the Braden (El Teniente) Copper Mine in Chile took 354 lives, and ranks as the most lethal metal mine fire in history. The mine was developed in the wall of a canyon over 900 m (3,000 ft) deep. Principal entrance was through a main haulage adit at the canyon bottom, and up through two internal shafts. Mining was by block caving from the top of the orebody with most of about 900 men on shift working in three production areas. Ore was transferred by gravity to the haulage level through a complex system of ore passes with associated ladderways. Normal mine ventilation was incast through numerous level portals and up- cast through the shafts and raises. The fire was confined to a maintenance shop just inside the portal of the lower production level. Smoke, gases and flammable vapors were drawn into the mine, and a subsequent explosion of the gases destroyed an air door and injected carbon monoxide into the workings. Falling water in a drainage raise near the fire made it downcast, which carried gases down to all the lower levels where they were drawn into the levels and then up connecting raises. Miners attempting to escape by climbing down the ladderways from the production levels were met and killed by the rising gases.

Jan 1, 1989

By C. W. Hoffman

A fairly recent development in the field of particle separation is now under investigation to determine its value to the mining industry. The method employed is probability sizing through a vibrating network of decreasing screen openings. While probability sizing as such is not new, the possibility of using it for coarse, highly abrasive ores at high tonnage rates has only recently appeared to merit practical consideration. The advantages to be gained by the use of probability sizing vs. conventional screening methods are: reduced space requirements for a high capacity unit, fewer moving parts, more versatile product sizing selection, reduced maintenance requirements and lower power consumption.

Jan 1, 1968

By Fernando Zevallos

La mayoría de las personas que se han involucrado en minería evidencian el gran nivel de sofisticación y la multidisciplinariedad en los procesos mineros. Actualmente, la tecnología está alcanzando a la ciencia ficción y nos presenta equipos de transporte autónomos o robots que realizan levantamientos topográficos. Sin embargo, existen nuevos retos que esta nueva tecnología debe afrontar como la disminución de impacto ambiental. En particular este trabajo técnico tratara los esfuerzos y dificultades que enfrentan la minería subterránea en descarbonización y gestión de residuos desde un enfoque de estudios de factibilidad o prefactibilidad y algunos ejemplos en operaciones.

Sep 30, 2022