Abstract The largest UNESCO World Heritage Site in the UK is found in Cornwall and west Devon, and its designation is based specifically on its heritage for metalliferous mining, especially tin, copper and arsenic. With a history of over 2000 years of mining, SW England is exceptional in the nature and extent of its mining landscape. The mining for metallic ores, and more recently for kaolin, is a function of the distinctive geology of the region. The mining hazards that are encountered in areas of metallic mines are a function of: the Paleozoic rocks; the predominant steeply dipping nature of mineral veins and consequent shaft mining; the great depth and complexity of some of the mines; the waste derived from processing metallic ores; the long history of exploitation; and the contamination associated with various by-products of primary ore-processing, refining and smelting, notably arsenic. The hazards associated with kaolin mining are mainly related to the volume of the inert waste products and the need to maintain stable spoil tips, and the depth of the various tailings’ ponds and pits. The extent of mining in Cornwall and Devon has resulted in the counties being leaders in mining heritage preservation and the treatment and remediation of mining-related hazards.

In carbonates, fault zone architecture, distribution of different types of fault rocks in fault cores (e.g., breccias, cataclasites), and the interplay between deformation and diagenesis must be considered to predict the flow properties of a fault zone. We present the results of an integrated structural and petrophysical study of two carbonate outcrops in central Italy, where faults are known to act as dynamic seals at depth, causing ≈70 m of hydraulic head drop in a karstified groundwater reservoir. The architecture of these fault zones is very well exposed, allowing for detailed mapping of the along-strike and across-strike distribution and continuity of fault cores and associated fault rocks over a distance of ≈8 km. More than 150 samples, comprising several fault architectural elements and carbonate host rocks, were collected in transects orthogonal to the fault zones. Fault rock porosity and permeability were measured on 1-inch plugs and then linked to characteristic microstructures and fault rock textures. The results of this integration consisted of ranges of porosity and permeability for each type of fault rock. A trend of increasing comminution and decreasing pore size is evident from the outer toward the inner portions of fault cores. Three types of breccias (crackle, mosaic, and chaotic) and various types of cataclasites were identified. Crackle breccias show the highest plug permeabilities (up to hundredss of mD), whereas the ultracataclasites have the lowest plug permeability (down to 0.01 mD, which is roughly equivalent to unfractured host rock). These data reveal the interplay between various fault rocks and host rock permeability and the development of permeability anisotropy of fault zones in carbonates.

ABSTRACT The extremely important role of groundwater has been largely overlooked in studies of meteorite and comet impact processes. Beyond the radius of plasma generation, impacts can produce massive shattering in saturated porous rocks. Fluid pressure rise reduces rock strength and facilitates hydrofracture, to produce intraformational monomict breccias, faulting, and generation of mobile polymict breccia slurries. Decompression of a deep “transient” crater accounts for complex central uplift and gravitational collapse of tremendous slide blocks that in turn cause injection and ejection of fluidized breccia. As pore fluid pressures equilibrate, frictional strength increases, and the structural form is locked into stability. Evidence is reported here for Kentland, Indiana, where quarry rocks display relatively low pressure-temperature (elastic to ductile transition, 100 kb–100 °C) impact phases of the model of D. Stöffler. Breccias include monomict, polymict, mixed polymict-fault, and conventional fault types. The monomict breccias are associated with aquifer beds and formed by pervasive shockwave transmission on impact. Polymict breccias are derived from all rock types and formed from late stage injection-ejection pseudoviscous slurries. These processes can apply to similar impacts like Wells Creek, Flynn Creek, Decaturville, Sierra Madre, and many others.

Slurry colloidal and particle interaction theory is described and applied to clay mineral suspensions. Mechanisms which affect the colloidal properties of the dewatering behaviour of clay mineral suspensions are described, after which the processes of coagulation and flocculation are discussed. Finally, sedimentation and self-weight consolidation are discussed as the mechanisms by which a low-density slurry transitions to a high-density slurry or soil.

With the myriad of measurement techniques and definitions of clays, the first question generally asked is “how much clay is there” in a sample? This often refers to the magnitude of a clay attribute in the sample and the answer to this question may vary depending on the measurement method. Does the method measure the clay-mineral type, the size distribution or mean size, the surface area, cation exchange capacity (CEC), rheology, or plasticity? Clay mineral type, particle size, and surface area are commonly used in mining operations to optimize oil-sand ore blending. In bitumen extraction and tailings management, where slurry behavior contributes to the process performance, propertiess uch as rheology and plasticity are also used. The previous chapters in the volume have introduced the various properties of clay particles and clay minerals. The present chapter describes the common methods of measuring clays and clay minerals in oil sands.

The clay fundamentals explained in the preceding chapters affect the macroscale oil-sands processes discussed in the following chapters of this volume through a series of mesoscale phenomena. Each mesoscale phenomenon is itself the subject of a field of science, and applications to different fields of engineering have led to a confusion of terminology. Understanding the underlying physical processes helps to elucidate the positive and negative effects of clay in oil-sands processes.

The clay minerals present in the oil-sands ore are responsible for some of the most challenging (and intriguing) processing behavior experienced on a routine basis in oil-sands surface mining. In previous chapters, significant details have been provided on how specific clay properties can give rise to changes in slurry rheology and interface phenomena. Because the bitumen extraction process relies heavily on manipulation of interfacial effects to enhance separation, changes in clay content in the ore, not surprisingly, can have a dramatic impact on the ability to process the material. This chapter provides an overview of the extraction process, the influence of clay minerals on bitumen recovery, and the challenges in reacting to changes in the ore clay content in a typical operation. The chapters that follow focus on the larger issue of tailings treatment to create a reclaimed landscape at the end of mine life.

The effects of clay on the geotechnical properties of oil-sands tailings deposits are discussed. The sources of fluid fine tailings are reviewed, and types of tailings deposits are described. The effects of clay on geotechnical index properties, hydraulic conductivity, compressibility, and shear strength are discussed, with example predictions for consolidation and strength gain in fines-enriched sand tailings and deep fines-dominated tailings deposits.