ABSTRACT Middle Triassic to Lower Jurassic continental conglomerate, sandstone, and mudrock are widely exposed in the highest tectonostratigraphic terranes (internal domains) of western and central circum-Mediterranean orogenic belts. These red beds are a key tectonic facies assemblage representing onset of the Tethyan rift-valley stage in the western Mediterranean, during which plate and microplate boundaries were localized during breakup of Pangea. These red beds likely define the boundary of the Mesomediterranean microplate, which played a key role in the Cenozoic evolution of the western Mediterranean. Red beds unconformably overlie Paleozoic metasedimentary and locally plutonic rocks, and they are covered by Early Jurassic and younger sedimentary strata; they are generally mildly deformed and only locally metamorphosed. Sandstone detrital modes vary from quartzarenite to quartzolithic, reflecting a provenance from Cambrian–Carboniferous metasedimentary rocks similar to those underlying the red beds. Reevaluation of previously published petrographic databases and detailed hot-cathodoluminescence (H-CL) analysis of quartz grains indicate that most quartz grains were derived from heterogeneous metamorphic, plutonic, and volcanic rocks. Evaluation of the diagenetic evolution of red beds using chemical-mineralogical analyses and H-CL analyses indicates that compaction and cementation played key roles. Compaction consists of brittle deformation, with breakage of quartz grains and production of early quartz cement, which closed the fractures, followed by a second stage of quartz cementation. Carbonate cements consist of dolomite, ankerite, and calcite. This last cement, related to dedolomitization/calcitization processes, produced carbonate crystals with iron oxides. The sandstone experienced intense reduction of intergranular volume during early stages of burial, as indicated by contrasting compactional porosity loss (COPL; mean of 31.1%) versus cementational porosity loss (CEPL; mean of 8.5%). These data demonstrate the minor role of cementation in reducing porosity and the prevalence of compaction as the main process destroying primary pores. The diagenesis of the analyzed red beds is variable within several internal domains of the orogenic belts, suggesting local influences related to the provenance and geotectonic evolution of each basin.

The particle-size distribution of oil-sands tailings has always figured prominently in the mine planning and overall operations and closure strategy in surface-mined oil sands. In oil-sands applications, the convention is to define the sand as the mineral components >44 μm in size and the fines as the mineral component which is <44 μm. The water-based extraction process uses 2 m 3 of water to extract the bitumen from 1 m 3 of oil sand, and as the bulk of this water is recycled, large containment areas are required to maintain a supply of extraction water. A significant proportion of water that is not recycled is retained in both the sand and fines components of the resulting tailings streams and the essence of tailings management comes down to separating and managing the water that can be recovered from the tailings. As the mining operations have become larger, and ore properties vary over wider ranges, the designation of sand and fines was simply inadequate in explaining the behavior of many of the tailings and a thorough understanding of the entire particle-size distribution became more important. Due in part to the upgrading and refinery operations often associated with bitumen production, the oil sands industry is relatively sophisticated in its approach to tailings characterization and tailings management. As a result, any discussion of clays can, and often does, include both a size and mineralogy component. In any case, there is no doubt about the importance of understanding and quantifying the clay component of any tailings stream when defining a dewatering or management strategy. Historically, it might have been argued that the strong correlation between clay content and fines content would be an adequate characterization and tailings-planning parameter. Although this is still largely true, the clay to fines correlations can sometimes be measurably different from operation to operation, resulting in varying tailings performance. In addition, some tailings-management options such as thickeners and centrifuges can separate the fines fraction and even the clay fraction in a fluid fine tailings stream. These upset operational modes can create what are known colloquially as Franken-Fines, a stream with a very disproportionately high clay content that can create an equally disproportionate tailings problem. The tailings strategies that will be discussed include composite/consolidated/non-segregating tailings, thickening, freeze-thaw processes, rim ditching, thin lift dewatering, and centrifugation. The present chapter outlines the evolution of many of these tailings-management strategies that have been tested extensively or are currently in use in the surface-mined oil-sands industry, with a particular emphasis on the importance of understanding the clay size and clay mineralogy in the evaluation and understanding of tailings dewatering performance.

Abstract The spatial distributions of mineralization and alteration in hydrothermal systems are complex and are often considered to be cryptic and problematic to quantify. We used wavelet analysis of conventional hyperspectral drillcore logs to demonstrate quantitatively that primary Au mineralization, common vein-hosted mineralogy (calcite and ankerite), host rock alteration mineralogy (sericite and chlorite) and regional-scale metamorphic assemblages (amphibole) organize spatially as multifractals. This documentation of multifractal spatial organization in Au and alteration mineralogy is sufficient to show that they are the result of underlying deterministic dynamic processes as opposed to random stochastic processes. The application of wavelets to three ore bodies (GQ, Vogue and Cosmo East) from the highly endowed Archaean Sunrise Dam hydrothermal Au system of Western Australia shows that the spatial organizations of Au and ankerite are more closely associated in GQ than in Vogue. The spatial organization of Au in Vogue is more strongly associated with calcite. Primary Au mineralization and infill carbonate mineralogy are more complexly organized than sericitic and chloritic host rock alteration. Although demonstrated here for a hydrothermal system, wavelet analysis is readily applicable to downhole or outcrop data from any deposit type.