In this chapter, the subject of ground improvement is introduced along with a discussion of the engineering parameters that can be addressed and a brief history of ancient practices. An overview of the objectives of designing a ground improvement plan is provided with a description of how ground improvement methodsmay be implemented into a project.The general categories and objectives of ground improvement techniques are also described. <...>

The term "soil" has many definitions, depending upon who is using the term. For example, to engineers "soil" is unconsolidated surficial material, whereas to many soil scientists it is mainly the medium for plant growth. A definition of soil that serves our purpose well is a slight modification of that given by Joffe'": a soil is described as a natural body consisting of layers or horizons of mineral and/or organic constituents of variable thicknesses, which differ from the parent material in their morphological, physical, chemical, and mineralogical properties and their biological characteristics; at least some of these properties are pedogenic (Fig. 1-1). Soil horizons generally are unconsolidated, but some contain sufficient amounts of silica, carbonates, or iron oxides to be cemented <...>

Over the years manufacturers have developed many generic forms of solid/liquid separator. The need to compete in the marketplace and gain a competitive edge, however, has led manufacturers to develop a plethora of variants. Rather than detailing all of these variants, this chapter attempts to give a descriptive overview of the generic equipment types and the main alternatives available to the design engineer (see Figure 1.1).

This study was undertaken to determine the source of iron in Comus Formation sedimentary rocks that were sulfidized during deposition of gold in the Megapit area of the Twin Creeks Carlin-type deposit. Sedimentary rocks in and near the Megapit contain ferroan dolomite, largely as overgrowths on iron-poor dolomite. Iron to form these overgrowths appears to have been released from mafic volcanic rocks that are interlayered with the sedimentary rocks. These igneous rocks have undergone two stages of hydrothermal alteration. The first stage involved formation of albite and iron-rich chlorite, possibly caused by interaction with seawater. The second stage involved destruction of the iron-rich chlorite by illite or sericite, which released iron to form ferroan dolomite in the sedimentary rocks. Comparisons show that transfer of iron from the igneous rocks to the sedimentary rocks can account for the present distributions of iron in these rocks. Relative to basalts, Comus Formation igneous rocks are enriched in iron and potassium. These results suggest that ferroan dolomite in sedimentary rocks is not solely a product of diagenetic processes and can form when iron is released from adjacent iron-bearing igneous rocks. Recognition of this additional mechanism for formation of ferroan dolomite expands the range of geologic settings that can be favorable for formation of gold deposits formed by sulfidation.