A COMPARATIVE STUDY FOR STRENGTH CLASSIFICATION
The importance of providing a system for strength classification is emphasized by the diversity of testing methods, number of representative samples needed, and testing equipment required. In the present work three Egyptian types of rocks: Limestone, Sandstone and Granite with different specimen sizes are used to carry out a comparative study concerning the determination of the compressive strength using uniaxial compression, point-load, and Schmidt hammer techniques. Testing results are statistically analyzed and correlated with some physical properties like porosity, density and sound velocity. * Associate Professor, Mining Department, Faculty of Engineering, Cario University TÜRKİYE X I I I . M A D E N C İ L İ K K O N G R E S İ , 1 9 9 3
Blast design in monumental stone quarries
ABSTRACT Controlled blasting design in situations where blocks of rock are required for finished monumental stone or building blocks has been described in this paper. The basic concepts applicable to blast design have been outlined and various aspects involving drilling of holes, spacing, burden, explosive selection, loading of holes have been discussed. The effect of blasting with relief and without relief on the development of the shear zone has been also considered. The entire design process including blast optimization has been described by an example.
Chemosymbiotic bivalves and stable carbon isotopes indicate hydrocarbon seepage at four unusual Cenozoic fossil localities
Four unusual Cenozoic fossil localities are identified here as ancient hydrocarbon seep sites using palaeontological, petrological, and stable carbon isotope data. Late Eocene carbonate-cemented sandstone bodies in the Wagonwheel Mountains in California were previously suspected to represent ancient hydrocarbon seep sites, but the relatively high δ13Ccarbonate values (−12.2 to −5.0‰) suggest oil rather than methane seepage. The Oligocene fauna of the Elmira asphalt mine, Cuba, was previously interpreted as a mix of freshwater and marine taxa, but all species are here identified as belonging to marine groups, including the bivalve families Lucinidae and Vesicomyidae, whose extant members live largely in symbiosis with chemoautotrophic endosymbionts. A carbonate concretion from this site showed δ13Ccarbonate values as low as −32.2‰, which most likely indicates methane seepage. A previously unpublished Oligocene fossil locality in Atlantico, northern Colombia, is dominated by large solemyid, mytilid, lucinid, and vesicomyid bivalves, which most likely lived with chemotrophic endosymbionts. Seepage of biogenic methane without a significant contribution of thermogenic methane is indicated by δ13Ccarbonate values as low as −51.3‰. We confirm that the Pleurophopsis-dominated sites of the Heath Shale and Lomitos Chert in northern Peru are ancient seep sites, although the previous identification of Pleurophopsis peruviana as a vesicomyid is doubtful.