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By Stuart St. Clair

EARLY in 1936, when the American Petroleum Institute issued -J "American Petroleum Industry," which was a survey of the current position of the petroleum industry, and its future outlook, and the figures for petroleum requirements .for 1950 and 1960 were widely publicized by the several oil journals, the impression was given that the petroleum- industry must be nearing maturity and would by 1950 have passed the high' point of its obligations to business progress in the United States.`' Let -us look at the figures which might conduce, this thought. Referring to p. 32 of the report, the total indicated crude-oil requirements in 1940 are 1,099,000,000 bbl-; for 1950, the peak, 1,109,800,000 bbl.; for 1960 a decline to 1,071,020,000 bbl. This downward trend, then established, is probably expected to continue. And this in the face of a crude production in 1935 of 993,942,000 bbl., 38,858,000 bbl.

Jan 1, 1936

By A. K. Snelgrove

Introduction ?Concerning the inland commodities, as wel to be drawen from this land (Newfoundland) there is nothing which our East and Northe.rly countries of Europe doe yeelde, but the like also may be made in (ît) as plentifully by time and industry : Namely, rosen, pitch . . . metalls, and many moe. All which the countries will aford, and the soyle is apt to yeelde ... For besides these alreadie recounted and infinite moe, the mountains generally make shew of minerall substance : Iron very common, lead, and somewhere copper. I will not auerre of richer metalls: albeit ... more then hope may be concieued thereof. " - Narrative of Captain Hayes, second-in-command to Sir Humphrey Gilbert's Expedition, IJ83 (From Hakluyt). The investigations set forth in the following pages were made in the field in Newfoundland during the summer of 1927, and later in the laboratories and library of McGill University, and in the library of the Canadian Geological Survey at Ottawa, with the purpose of collating and adding to our knowledge of the geology of an area roughly wedge-shaped in outline, and nearly nine thousand square miles in extent, stretching across the centre of the island of Newfoundland, from the southwest to the northeast coasts. To the description of this district, which contains most of the known mineral occurrences of Newfoundland, the term mineral belt is here introduced.

Jan 1, 1928

By D M. Aranha, M A. Fonseca, M Echtern

The regional syndeformational metamorphism affecting the Itabira Iron Formation (IIF) at Quadrilßtero Ferrffero (QF) was formerly discussed by Dorr (1965), who proposed that quartz grain size could monitor the metamorphism, according to James (1955), and that the formation of haematite could be the result of the synchronous metasomatic process. Herz (1979) suggested the existence of three metamorphic zones, not mentioning the haematite formation. It could be observed that the primary oxide phase in the IIF is magnetite and most of the hard haematite was derived from the metamorphic replacement of magnetite, forming micaceous or schistose haematite. Differently from most iron formations in the world, the formation of haematite deposits at QF occurred under high oxygen fugacity during metamorphism. The haematite microlaths display a strong preferred orientation, which determines the alongated shapes of the fragments. The terms foliated and unfoliated haematite have been applied by Dorr to the micaceous or schistose haematite, and to the isotropic, hydrothermally derived haematite. Under the microcope, the haematite exhibits a strong crystallographic or lattice orientation encircling the magnetite and martite porphyroclasts. The strain rate determined and defined the textural variation, size and economic importance of the deposits and the ore grade. Metamorphism at QF increases eastward and resulted in the formation of a gruneritic Fe-Mg amphibole, at the western portion, followed by a cummingtonitic amphibole at the central-western part, succeeded by the actinolite zone at the central-eastern part, and finally to the tremolite-anthophyllite zone to the east. These zones, arranged in a north-south pattern, can be followed in the pelitic units, whereas appear sericite-chlorite, kyanite-chloritoid and garnet-staurolite respectively. Carbonate geothermometry in IIF also may support the metamorphic variations. At the western zone the haematite forms small lenses within the itabirite, P-contents are slightly higher than in the remaining IIF, haematite grain size is minute, resulting in a submicaceous texture and the amount and dimension of relict magnetite within haematite is greater than in the other parts of QF. Jangada and Serra Azul deposits are examples of this zone. The central-western zone is characterised by significant haematite deposits, in considerable quantity and size, haematite grain size increased, in order to produce a micaceous texture, the P-contents and the amount of magnetite decreased. Pico do Itabirito, Cappo Xavier, Capitpo do Mato and Tamanduß correspond to the deposit type of this zone. At the eastern-central portion the amount of the hard haematite deposits decreases, increasing the soft haematite ore due to higher strain rates. However, it can be perceived that the relict magnetite almost disappeared and the haematite grain size became coarser than the haematite from the western zones. At the eastern zone, the haematite deposits exhibit typical schistose texture, the magnetite porphyroclasts are absent and the lowest P-grades in the haematitic iron formation. The haematite bodies characteristic from this zone are Andrade, Morro Agudo and the deposits at the Itabira District. The hydrothermally derived compact and isotropic haematite deposits, formed subsequently to the micaceous haematite bodies, were generated after deformation ceased, but under very high fluid pressure. The metamorphic reactions magnetite + quartz + H2O = grunerite + haematite and magnetite + quartz + H2O = grunerite + O2 were decisive in the formation of the metamorphic haematite deposits.

Jan 1, 2007

By Henry P. Wheeler

H ELIUM (chemical symbol: He) is a member of a family of normally gaseous elements, which, because of their zero valence and corresponding lack of chemical activity, are called the "noble" or "inert" gases. It is a monatomic element with an atomic number of 2, and it exists naturally in two stable isotopic forms-He3, with an atomic mass of 3.0170, and He4, with an atomic mass of 4.0039. With the exception of a trace (10-6 percent) of He3, all of the naturally occurring helium is He4. Two unstable isotopes-He5, with atomic mass 5.0137, and He6, with atomic mass 6.0208-are listed by various scientists, but the existence of He5 is questioned by some of them. He6 is radioactive, with a half-life of 0.8 second. Helium was discovered in 1868 in the gaseous atmosphere surrounding the sun. Although several scientists studied the solar chromosphere that year, it is generally agreed that J. Norman Lockyer of England should be credited with the discovery of helium, which he named, deriving the word from "helios," the Greek name for the sun. It was not found on earth until March 1895, when William Ramsay of London produced a small amount from a sample of cleveite, a uranium-bearing mineral. In 1905, H. P. Cady and D. F. McFarland of Kansas found helium in natural gas produced from a well near Dexter, Kans., and for the first time a large source of helium became available.

Jan 1, 1952

By F. Habashi

"The rare earths industry started in Austria in 1887 by Carl Auer von Welsbach (1858-1929) Professor of Chemistry at the University of Vienna. The process was based on monazite sand transported from Brazil as shipping ballast free of charge. This made possible producing thorium, cerium, and other rare earths at a low cost, thus permitting the growth of the industry. However, once the Brazilian authorities realized the strategic importance of the sand, shipping was stopped. Brazil then started its own processing of the sand in 1949. The background for Auer’s work, the role of Robert Bunsen in Heidelberg, and the invention of the spectroscope will be presented. INTRODUCTIONHeidelberg on the Neckar (Figure 1) was the meeting place for chemistry students from all over Europe in the nineteenth century. Her university founded in 1386 had already a famous professor of chemistry and medecine in the Faculty of Medicine by the name Leopold Gmelin whose three - volume Handbuch der theoretischen Chemie appeared in 1817-1819, that became later a multi-volume monumental work. As successor to Gmelin came Robert Bunsen (Figure 2) in 1852 who made this university town the Mecca of chemistry students. One of his students, the English Henry Roscoe (1833-1915) who became later a distinguished professor in Manchester, described him as follows: ""As an investigator he was great, as a teacher he was greater, as a man and a friend he was greatest""."

Jan 1, 2012

By Alastair Torrance, Mitchell Nipperess, Andrew Olsson, Italo Onederra, Gary Cavanough

Components of bulk explosive products include ammonium nitrate, water, fuel, stabilizers, and calcium nitrate. The physical attributes include prill/emulsion ratio, density, and viscosity and in the case of prilled ammonium nitrate, hardness, size distribution and fuel oil absorption. These components and attributes in conjunction with ground conditions determine all aspects of explosive performance including the risk of fume. This paper presents a fume risk assessment matrix of explosives components and physical attributes as a function of a simple description of ground conditions. Instrumentation to provide a measure of the quality of the explosive product are also described and these include both “on bench” physical measurements and laboratory analysis. “On bench” methods include “in hole “density, velocity of detonation (VOD), detonation pressure and detonation temperature. Part of the quality control process involves a mobile laboratory unit which at this stage can provide measurements of water content, ammonium nitrate content, calcium nitrate content, fuel content, prill characteristics and prill/emulsion ratio. This unit can be taken to sites to enable the testing of bulk and sensitized products at site rather than after transportation.

Jan 1, 2015

By David L. Borusiewicz, M. Suri Surendra

"Abstract Helical piles have been used as anchors and for supporting lightly loaded structures as a method of underpinning, etc in the past. Recently, helical piles are being used to support new structures because of their simple installation process using relatively light and mobile equipment. This paper presents the results of evaluation and design performed for the temporary support of existing piers during a bridge rehabilitation project.INTRODUCTIONThe helical screw foundation was invented and patented by Alexander Mitchell in England in 1833. He installed screw piles to support lighthouses in the tidal basins of England. Many applications in the earlier years in the USA were in North Carolina and in Florida to support lighthouses (in coastal plain deposits). A lighthouse of similar foundation design is still in use at Key Biscayne, Florida.In the USA, the helical piles were reintroduced as foundation elements for electrical transmission towers. Helical piles were also used for anchoring guys of self supported towers and as tie-backs for excavation support systems. Typically, helical piles are being used for supporting lightly loaded buildings and for underpinning buildings undergoing distress as a means of remediation. The helical piles are not commonly used in the transportation industry.HELICAL PILESHelical pile is a segmented deep foundation system with helical bearing plates welded to a central steel shaft. Load is transferred from the shaft to the soil through these bearing plates. Central steel shafts are available in either a square shaft (Type SS) or a round shaft (Type RS). The Type SS series are available in 38 mm to 57 mm square sizes. The Type RS series are available in 73 mm to 114 mm diameter sizes. Type SS-RS combinations are also available for compression applications in soil conditions where dense/hard soils must be penetrated with softer/loose soils above the bearing strata.The leading segment consists of a shaft with one or more helical plates that are welded to the shaft. The plates vary in diameter from 203 mm to 355.5 mm and have a thickness of 9.5 mm or 13.7 mm. Typically the plate diameter increases from the bottom of the shaft upward. A helical bearing plate or helix is one pitch of a screw thread. All helices, regardless of their diameter, have a standard 76 mm pitch. Being a true helical shape, the helices do not auger into the soil but rather screw into it with minimal soil disturbance. Helical plates are generally spaced a distance of two to three times the diameter of the plate directly below in order for them to function independently as individual bearing elements. A typical detail of helical pile is shown on Figure 1."

Jan 1, 2014

By E. S. Moore

Although nickel was in use in alloys long before the Christian era, the metal was not discovered until 1751, when Cronstedt recognized it in niccolite from Sweden. The Chinese apparently used a nickel alloy, known as "pahfong" thousands of years ago and Persian coins dating farther back than 200 B.C. consist of a copper-nickel alloy similar to some of those now in use in coins. The pure metal was first prepared about 1775 and the metal was refined for commercial purposes some years later. The nickel industry did not attain much prominence until the ores in New Caledonia were discovered. Exports of ore from that country began in 1875 and since that date there has been an ever-increasing world output of nickel and a great expansion in the uses of the metal except during short periods of commercial and industrial depression. Previous to 1875, for a number of years, Norway was the chief producer, although the metal was mined also in Sweden, Finland, Italy, Germany, Austria, France, China, the United States and other countries. With the discovery of nickel deposits in the Sudbury district, Ontario, a new factor was introduced into the nickel industry and Sudbury has since become the overwhelmingly dominant feature in the world's nickel markets. Although nickel was first discovered in Canada as early as 1848 near the north shore of Lake Huron and nickel-copper sulfides were found in 1856 by surveyors working close to the present location of the important rnine at Creighton, in the Sudbury field, it was not until 1883 that any importance was attached to this field. In that year copper sulfide attracted attention where the main line of the Canadian Pacific railroad was being projected across Canada to the Pacific coast. Mining began near this discovery in 1889 but in the meantime operations had begun in 1886 in other parts of the field and by 1890 about 100,000 tons of ore had been raised. In the Sudbury field, as in Norway and at the old Lancaster Gap mine in Pennsylvania, the ore was first mined for its copper content and difficully in the refining of the copper led to the discovery of the important proportions of nickel in the ore. No. 3 property of the International Nickel Co., now known as the Frood, the greatest deposit in the

Jan 1, 1932

By Daniel G. DiCanio

This report describes a computer-based model for estimating the tangible costs of injuries and deaths from work-related accidents in underground coal mines. The study undertook to identify and quantify the elements of accident costs, including field visits to coal mines, insurance carriers, and public agencies. The mathematical models developed for each tangible element of accident cost are presented in Volume I -of the report. A listing of the computer programs which comprise the model and instructions for using the programs are presented in Volume II. Statistical distributions of mining family characteristics, data on 95 miners killed in underground accidents, and other basic data used to develop the model are presented in Volume III. Application of the model to a data base of 9,286 accidents which occured in underground bituminous coal mines during 1974 yielded a total of $56,900,000 in tangible costs to industry, mining families, and public agencies. Loss of income to the families of miners injured or killed in these accidents accounted for 47 percent of the total.

Jan 1, 1976

By Terry L. Muldoon

This report describes development and demonstration of an upgraded stench fire warning system for underground wines. Current systems, which have been used since before 1920, release an ethyl mercaptan mixture into the mines' compressed and/or ventilation air during emergencies. Miners, when smelling ethyl mercaptan, evacuate the mine according to predetermined plans. These systems, while simple, have problems with safety and reliability. The upgraded system overcomes these problems. The system uses a different stench agent, is less toxic, less nauseating, and less corrosive than ethyl mercaptan. These combined with the feature of thiophane not reacting with iron oxides, makes the upgraded system safer and more reliable. The system also uses a combination of two simple principles: a standpipe with pressure balancing to provide a constant head, and a sized orifice to control the rate of release of the stench agent. This system enables the mine to release the agent for a longer period which provides better coverage and to ensure that miners will not be exposed to potentially toxic concentrations of the stench agent. The system is easy to operate, requiring only the turning of two 1/4-turn ball valves. The upgraded system has been successfully tested during two evacuation drills at an underground uranium mine. Using three injectors (one on the compressed air line and one on each of two intake air shafts), the system exhibited significant improvements in warning times over the mine's existing system. This report provides a detailed description of the system design and its demonstrated performance in two mine demonstrations.

Jan 1, 1981

By A. U. Seybolt, R. E. Honnemon

THE purpose of this communication is to present activity data of nickel in the Ni-A1 binary system that was obtained for oxidation studies in this system. This data has been calculated from previous aluminum activity data at 1000°C1,2 by two types of Gibbs-Duhem integrations. These results should be of particular current interest to oxidation studies of aluminide coated nickel-base superalloys3 as well as other problems. The aluminum activity of Steiner and Komarek1 is plotted in Fig. 1 as a function of composition in Ni-A1 alloys at 1000°C. The dashed parts of the aluminum curves represent our approximate extrapolations from the directly measured regions. In the terminal solution regions (a and L phases) standard parabolic solution functions of the following form are assumed: where i is the component subscript, Ki is a constant at a fixed temperature, and xi is the atom fraction. The resultant nickel activity curve at 1000° C from the Gibbs-Duhem integration4 of the aluminum data is shown in Fig. 1. The solubility ranges of the phases present in the Ni-A1 binary at 1000°C are also denoted at the bottom of Fig. 1. Corresponding values of the nickel activity, aNi and yNi, are listed in Table I at useful compositional intervals. including phase boundary values. The aNi and yNi data listed in Table I are subject to the uncertainties present in the experimental aluminum activity data1 and to deviations from parabolic solution behavior in the terminal solutions. The errors introduced into aNi and yNi due to the parabolic solution assumption are expected to be relatively small (<20 pct of the values given) in all the phases except the liquid phase. Some deviation from parabolic solution behavior in the liquid phase is indicated

Jan 1, 1970

By Wm Petruk

"The tungsten-bismuth-molybdenum deposit in southwestern New Brunswick occurs in greisenized and silicified tuffite * and feldspar porphyry in and adjacent to volcanic necks. The ore minerals occur as veins and veinlets and as disseminated grains in gangue. These minerals can be grouped into three assemblages. Assemblage 1 consists of oxides and phosphates of W, Ti, Fe, Nb, Sn, Ta and rare-earth elements, with the main minerals being deposited in the sequence wolframite, rutile, cassiterite. Assemblage 2 consists of arsenopyrite, molybdenite and bismuth, and assemblage 3 of sulphides with minor cassiterite and arsenopyrite. Sphalerite is the main sulphide mineral, but it contains minute inclusions of copper-tin- and indium-bearing minerals. Textural relations suggest that most of the elements can be recovered from this ore by conventional mineral beneficiation and extraction methods, but a variety of techniques must be employed. It is expected that the wolframite and molybdenite can be recovered satisfactorily, but poor recoveries are expected for bismuth and cassiterite. A sphalerite concentrate can be readily obtained by flotation, but it would contain a wide variety of elements. It is suggested that leaching be used to recover the bismuth and the elements in the sphalerite concentrate."

Jan 1, 1973

Major Francis Hamilton Buchanan coined the term `laterite&apos; (Latin; brick-rock) in 1807 for the red earths used for building blocks in southern India. Although these earths were actually weathered basalts, the term is now applied to weathering profiles developed upon a wide range of bedrocks. The Ni-laterites are a special class within the broad laterite family.

Jan 1, 1996

Australian coals tend to be young in geological age and high in ash by world standards; preparation of the coal before marketing is almost universal. On the basis of float and sink data from 39 locations in the Eastern Australian coalfields, the coals are placed in four categories representing increasing difliculty in their washability characteristics. These seem to be related neither to the geological age nor the geographical position of the deposit and Hunter Valley coals, for example, span all categories. The influence of crushing on the washability of Australian coals is briefly considered and from limited data it is concluded to be appreciably smaller than for British or North American coals. A strategy for the float and sink analysis of Australian coals is proposed and the influence of washability characteristics on current trends in the selection of separating processes for coking and steaming products is discussed.

Jan 1, 1979

By A. Opara

The weathering of coal mine waste rock releases iron, calcium, sulfate and associated trace elements like selenium [Se], which are introduced to seepage waters. Nitrogen species, such as nitrate and ammonia, are also found in association with coal-mining drainages mainly due to leaching of residual blasting compounds. Elevated concentrations of Se are a ubiquitous occurrence in coal mining environments in British Columbia, with values ranging from below 50 to over 500 µg/L in site waters. Selenate is the most common form of selenium found in waste rock seepages, and is exceedingly mobile in aerobic freshwaters. A major concern with waterborne Se in British Columbia is the potential for its bioaccumulation in aquatic food chains. Treatment to remove Se from coal-mining wastewaters has proven to be challenging for conventional water treatment technologies. Compounding this challenge, many streams are characterized by high flows and low selenium concentrations. Conventional membrane and ion exchange treatments produce concentrated brine streams that are difficult to treat or require disposal. Conventional biotreatment systems use excess nutrients to provide the required electrons to compensate for inefficient and variable electron availability, as well as to adjust reactor chemistry. The Electro-Biochemical Reactor (EBR) technology provides electrons to the microbes directly at a low voltage potential (1-3 V), supplying a controllable and consistent supply of useable electrons to the system and microbes at low current. In this manner, the EBR technology overcomes the shortcomings found in conventional systems, as it reduces the required nutrient addition and provides a more controllable, efficient, economical, and robust biotreatment system than found in past generations of biological treatment systems. Additionally, the EBR process does not produce excess solids or biomass; therefore, solids management post-treatment is not required. Laboratory EBR bench-scale and on-site pilot-scale systems were used to treat five British Columbia coal mine wastewaters; influent Se concentrations ranged from 35 µg/L to 531 µg/L. Se treatment targets for the tested waters ranged from 5 to 10 µg/L. Mean Se concentrations in EBR effluents ranged from 0.5 µg/L to 1.4 µg/L, while reducing sulfate concentrations. The test data demonstrate that the EBR technology is an effective Se removal option for British Columbia?s coal-mining wastewaters.

Feb 23, 2014

By A. Opara

The weathering of coal mine waste rock releases iron, calcium, sulfate and associated trace elements like selenium [Se], which are introduced to seepage waters. Nitrogen species, such as nitrate and ammonia, are also found in association with coal-mining drainages mainly due to leaching of residual blasting compounds. Elevated concentrations of Se are a ubiquitous occurrence in coal mining environments in British Columbia, with values ranging from below 50 to over 500 µg/L in site waters. Selenate is the most common form of selenium found in waste rock seepages, and is exceedingly mobile in aerobic freshwaters. A major concern with waterborne Se in British Columbia is the potential for its bioaccumulation in aquatic food chains. Treatment to remove Se from coal-mining wastewaters has proven to be challenging for conventional water treatment technologies. Compounding this challenge, many streams are characterized by high flows and low selenium concentrations. Conventional membrane and ion exchange treatments produce concentrated brine streams that are difficult to treat or require disposal. Conventional biotreatment systems use excess nutrients to provide the required electrons to compensate for inefficient and variable electron availability, as well as to adjust reactor chemistry. The Electro-Biochemical Reactor (EBR) technology provides electrons to the microbes directly at a low voltage potential (1-3 V), supplying a controllable and consistent supply of useable electrons to the system and microbes at low current. In this manner, the EBR technology overcomes the shortcomings found in conventional systems, as it reduces the required nutrient addition and provides a more controllable, efficient, economical, and robust biotreatment system than found in past generations of biological treatment systems. Additionally, the EBR process does not produce excess solids or biomass; therefore, solids management post-treatment is not required. Laboratory EBR bench-scale and on-site pilot-scale systems were used to treat five British Columbia coal mine wastewaters; influent Se concentrations ranged from 35 µg/L to 531 µg/L. Se treatment targets for the tested waters ranged from 5 to 10 µg/L. Mean Se concentrations in EBR effluents ranged from 0.5 µg/L to 1.4 µg/L, while reducing sulfate concentrations. The test data demonstrate that the EBR technology is an effective Se removal option for British Columbia?s coal-mining wastewaters.

Feb 23, 2014

By G. M. Bernard

The Andacollo gold mine is located near the small town of Andacollo, Chile (population 14,000) in the fourth region. It is approximately 35 miles by paved road from the coastal city of La Serena, and Santiago lies about 300 miles to the south (see map.) Site elevation varies between 3300 feet and 4200 feet. The climate at the site is moderate but arid, with an average annual rainfall of only five inches. Because there is little rain, and the temperature varies only a few degrees (57"F to 75°F); there are no freezing, solution dilution, or pad saturation problems. The climatic conditions are ideal for heap leaching.

Jan 1, 1996

By Larissa Carolina Ferreira

O impacto das atividades do setor de mineração sobre o meio ambiente tem levado a estudos visando, tanto à utilização racional dos recursos naturais, quanto o tratamento de efluentes gerados durante os processos. A caracterização de efluentes é uma etapa importante, podendo apontar erros nos processos de beneficiamento, parâmetros em desacordo com a legislação ambiental e guiar etapas de desenvolvimento de técnicas do tratamento. Este trabalho consiste na caracterização de um efluente da etapa filtragem de uma mineradora de minério de ferro do quadrilátero ferrífero comparando os valores encontrados com as exigências da norma CONAMA 357/2005 e 430/2011, de forma a enquadrá-los na categoria de águas doces classe 1 e de lançamento de efluentes. O pH encontrado (9,8), turbidez (2133 NTU) e sólidos sedimentáveis (28mL/L), estão fora dos padrões permitidos e mostram grandes problemas em relação aos sólidos presentes na amostra. O diâmetro médio das partículas (8,54µm), indicou a predominância de partículas ultrafinas de difícil sedimentação. Os elementos majoritários Al, Fe, P e S, 0,296; 1,6; 0,218 e 26,5 mg/L, respectivamente, também apresentaram valores acima do permitido para água doce classe I. As análises indicaram que o efluente necessita de tratamento prévio para posterior descarte.

Aug 16, 2017

By Jun Lu, Mark Van Dyke, Daniel W. H. Su, Greg Hasenfus

"This paper presents the geologic and ground control challenges that were encountered by CONSOL Energy’s mining operations in southwestern Pennsylvania. A sandstone-to-limestone geology transition was encountered by Mine A, where the primary 8-foot bolts were anchored in claystone. Upon experiencing roof sags and a roof fall in the return entry, 6-foot high-tension, fully-grouted primary bolts were employed along with 16-foot center cable bolts at every other strap to improve beam building and to ensure proper anchorage into the competent limestone. No longwall delay was reported within this geologic transition zone, although there was some difficulty in maintaining an open #2 entry airway behind the longwall face.The geologic encounter in Mine B was more complex, where fluvial deposits of massive sandstone channels, shale channels and pyritic-rich, green claystones were encountered on both sides of the mains, and which impacted both development and longwall ground control. In particular, poor transitional roof areas near the edges of the sandstone and shale channels often posed significant ground control challenges. In addition, hydraulic fracturing was sometimes utilized to enhance caving of massive sandstone behind the shields to relieve pressure at the face. Longwall face conditions and advance rates were documented to illustrate the effects of sandstone channels, shale channels, and green claystones on safety and productivity and to demonstrate the effectiveness of the hydraulic fracturing.Shale channels, slickensided zones, laminated roof zones, soft floor, and a regional syncline were encountered in Mine C, the combination of which posed unique ground control challenges during both development and longwall mining. The presence of soft floor, coupled with the presence of thick floor coal and deep cover, resulted in headgate convergence during retreat of the first right-hand longwall panel. Two-piece 8-foot bolts were sometimes observed to fail at the coupler within the laminated roof zone, and 6-foot, 1-piece, fully-grouted point-anchor bolts were employed as the primary bolts thereafter."

Jan 1, 2015

By Douglas A. Anderson

Much progress has been made in understanding the forward process for blast vibration simulation: that is, how to create a resultant seismogram from an empirically determined seed waveform. What has not been successfully investigated to date is the reverse process: Determining the contribution of each borehole to the resultant seismogram. It might seem that these should be two sides of the same coin, but the reverse process is much more complicated. That is because the source, geological path, and receiver contributions must be unraveled and then dissected. If that can be done, a relationship can be developed between the seismic source properties and the explosive interaction with the surrounding rock. This paper presents a first step in the unraveling process, through analysis of blast seismograms using wavelet transforms.

Jan 1, 2013