269 resultados para Dredging spoil


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"U.S. Bureau of Mines contracts J0166054 and J0166055."

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Prepared for Illinois Dept. of Energy and Natural Resources, Energy and Environmental Affairs Division.

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The potentially responsible parties (PRPs) have removed the beaver dams and have collected the sediment samples they need for treatability studies. The treatability studies will establish the correct silt fence to minimize releases of sediment during the actual dredging to occur this fall. The studies will also determine the types and amounts of materials (lime, kiln dust, fly ash, etc.) required to stabilize the sediment, chemically tie up the metals and insure the sediment mixture will bear the weight of the cap on the Interim Storage Cell where the sediment will be placed. The Illinois Environmental Protection Agency (Illinois EPA) anticipates work to be completed by late fall or early winter 2004, if lake and river levels that affect the South Ditch are at their normal seasonal levels.

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Description based on: Vol. 16, no. 1 (Jan. 1912).

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New surveys were completed and data from the field sheets were kindly furnished by the U. S. Coast and Geodetic Survey to the Woods Hole Oceanographic Institution for use in dredging and coring operations. This field work, first reported in 1936, was continued from time to time until 1941 as new soundings became available. Rock dredging and coring has been carried out in every major canyon on the slope from Corsair Canyon at the tip of Georges Bank to Norfolk Canyon off the entrance to the Chesapeake. Numerous cores have also been taken from the areas in between; and while the whole slope from Georges to the Chesapeake has not been covered, it is believed that no significant areas have been missed. In the following report the tows and cores will be described by areas from Georges Bank southwards, as the same region was revisited in successive years. The various samples, however, will be referred to by number followed by the year in which they were taken. The material is in storage in the Woods Hole Oceanographic Institution and in the Museum of Comparative Zoology at Harvard University.

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The effects of dredging on the benthic communities in the Noosa River, a subtropical estuary in SE Queensland, Australia, were examined using a 'Beyond BACF experimental design. Changes in the numbers and types of animals and characteristics of the sediments in response to dredging in the coarse sandy sediments near the mouth of the estuary were compared with those occurring naturally in two control regions. Samples were collected twice before and twice after the dredging operations, at multiple spatial scales, ranging from metres to kilometres. Significant effects from the dredging were detected on the abundance of some polychaetes and bivalves and two measures of diversity (numbers of polychaete families and total taxonomic richness). In addition, the dredging caused a significant increase in the diversity of sediment particle sizes found in the dredged region compared with elsewhere. Community composition in the dredged region was more similar to that in the control regions after dredging than before. Changes in the characteristics of the sedimentary environment as a result of the dredging appeared to lead to the benthic communities of the dredged region becoming more similar to those elsewhere in the estuary, so dredging in this system may have led to the loss or reduction in area of a specific type of habitat in the estuary with implications for overall patterns of biodiversity and ecosystem function. (c) 2006 Elsevier B.V. All rights reserved.

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Acacia harpophylla F. Muell. (brigalow) used to naturally occur over a range of about 50 000 km(2) in Queensland and New South Wales, Australia. Large scale clearing for agriculture has reduced the area to less than 20 000 km(2) and it is estimated that 20-25% of vertebrate fauna living in brigalow communities will become locally extinct as a result of the current clearing induced loss of habitat. Some coal mining companies in central Queensland have become interested in providing habitat for the endangered bridle nail-tailed wallaby that lives in brigalow vegetation. However, there is little known about establishment techniques for brigalow on mine sites and other disturbed ground; an understanding of brigalow biology and ecology is required to assist in the conservation of this threatened vegetation community and for re-creation of bridled nail-tail wallaby habitat in the post mining landscape. Brigalow is an unusual species of Acacia because it is not hard-seeded and germinates readily without the need to break seed-coat imposed dormancy. Germination trials were undertaken to test the ability of brigalow seed to germinate with a range of temperatures and salinity levels similar to those experienced in coal mine spoil. Optimum germination was found to occur at temperatures from 15 to 38 degrees C and no germination was recorded at 45 degrees C. Brigalow was very tolerant of high salt levels and germinated at percentages greater than 50% up to the highest salinity tested, 30 dS/m. Germination of greater than 90% occurred up to an electrical conductivity of 20 dS/m. The results indicate brigalow seed can be sown in summer when rains are most likely to occur, however, shading of the seed with extra soil or mulch may ensure the ground surface does not become too hot for germination. Because of its ability to germinate at high salinity levels, brigalow may be suitable for use in saline mine wastes which are common on sites to be rehabilitated after mining.

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This report presents the preliminary results of the study of rocks and sediments obtained by dredging during four cruises of the R/V Jean Charcot and R/V Le Suroit during a cooperative program between CNEXO and CEPM (CH 58: April 1975; SU 01: December 1975; CH 66: February 1976; and CH 67: March 1976). Several dredges on the continental slope of the Goban Spur recovered "granitic" rocks on two morphological structures, Granite Cliff and "Menez Bihan" (Pautot et al., 1976), in water depths ranging from 3200 to 4200 meters. According to the radiometric age and petrology, the granodiorite appears to have a close affinity with similar igneous facies which have been described in Iberia (Capdevilla et al., 1973) and attributed to the Variscan intrusive episode which is also found in the nearby continental area (southwest Great Britain and Brittany, France). They often are coated by a centimeter-thick layer of ferromanganiferous deposits (Shaaf et al., 1977).

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The cores described on the following pages were obtained on the Scripps Institution of Oceanography SCAN Expedition during March 1969 to February 1970 aboard R/V Argo. The primary purpose of the expedition was to conduct geological surveys of prospective drilling sites for the Deep Sea Drilling Project. A total of 106 locations in the Pacific Ocean were geologically sampled, usually by coring but, on occasion, by dredging. The following descriptions are of all the cores taken on SCAN which are available at Scripps for sampling and study.

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Sea floor dredging by the H.M.S. Challenger, the U.S.S. Albatross, the U.S.S. EPC(R) 857, and vessels of the Scripps Institution of Oceanography shows that extensive deposits of manganese nodules are on the deep sea floor and that crusts of manganese dioxide cover many seamounts. Sea floor photography reveals that in some places these crusts are quite continuous and the nodules are closely packed. These crusts and nodules are fully oxidized and hydrated mixtures of man¬ganese and iron plus earthy impurities. Also, relatively high concen¬trations of the trace elements nickel, copper, and cobalt are present.

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The Potengi River estuary has been affected by various anthropogenic factors over the years, as periodic dredging, industrial and domestic waste, traffic and other factors, causing various environmental disasters, including the notorious ecological accident in July 2007, which covered the municipalities of São Gonçalo do Amarante, Macaíba and Natal. Foraminifera serve as viable study tools in these environments; they are able to identify ecologically stressed environments, pointing out hydrographic changes and depositional environments in estuaries. The necessity to check the differences in environmental gradients in places anthropically impacted in Potengi River and adjacent inner shelf through species of foraminifera, and, the responses of these organisms to physical, chemical and geological factors is to provide baseline in the diagnosis of environments. The results show the dominance of opportunistic Ammonia tepida, Bolivina striatula, Quinqueloculina patagonica and Q. miletti especially in regions close to shrimp farms and Baldo Channel sewage in fine grain environments; and Q. lamarckiana indicates penetration of the saline waters in Potengi River. The occurrence of low-salinity tolerant foraminiferal species typical of mangrove environments as Trochammina inflata and T. squamata in Potengi River Channel suggest they probably could have been transported from mangrove area near the Potengi river mouth to the inner shelf regions. These findings suggest Potengi River is able to export mixohaline and mangrove organisms to inner shelf. Two distinct environments were observed, the outermost area is more influenced by marine influence and the innermost area is less influenced. Calcareous and agglutinated species dominate Potengi River, while mouth and inner shelf areas are dominated by calcareous, agglutinated and porcelaneous species, which are typical of highly saline and hydrodynamic environments and the contributive factors that controls foraminiferal distribution were balance of marine and freshwater currents, grain size, availability of CaCO3 and organic matter.

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The Potengi River estuary has been affected by various anthropogenic factors over the years, as periodic dredging, industrial and domestic waste, traffic and other factors, causing various environmental disasters, including the notorious ecological accident in July 2007, which covered the municipalities of São Gonçalo do Amarante, Macaíba and Natal. Foraminifera serve as viable study tools in these environments; they are able to identify ecologically stressed environments, pointing out hydrographic changes and depositional environments in estuaries. The necessity to check the differences in environmental gradients in places anthropically impacted in Potengi River and adjacent inner shelf through species of foraminifera, and, the responses of these organisms to physical, chemical and geological factors is to provide baseline in the diagnosis of environments. The results show the dominance of opportunistic Ammonia tepida, Bolivina striatula, Quinqueloculina patagonica and Q. miletti especially in regions close to shrimp farms and Baldo Channel sewage in fine grain environments; and Q. lamarckiana indicates penetration of the saline waters in Potengi River. The occurrence of low-salinity tolerant foraminiferal species typical of mangrove environments as Trochammina inflata and T. squamata in Potengi River Channel suggest they probably could have been transported from mangrove area near the Potengi river mouth to the inner shelf regions. These findings suggest Potengi River is able to export mixohaline and mangrove organisms to inner shelf. Two distinct environments were observed, the outermost area is more influenced by marine influence and the innermost area is less influenced. Calcareous and agglutinated species dominate Potengi River, while mouth and inner shelf areas are dominated by calcareous, agglutinated and porcelaneous species, which are typical of highly saline and hydrodynamic environments and the contributive factors that controls foraminiferal distribution were balance of marine and freshwater currents, grain size, availability of CaCO3 and organic matter.