The Energy Construct cost-effectively. The author concludes that wind energy has the greatest potential for near-term expansion. However, smaller-scale use of solar, geothermal, biomass, and ocean sources along with current hydroelectric sources could add up to make a significant contribution. The advantages and disadvantages of each renewable energy option are examined. Nuclear energy is also supported by the author as the only way to produce large amounts of emission-free power. The author pays close attention to the safety of nuclear energy and provides a unique comparison of the safety of energy generation from a number of sources. Fossil energy is then examined with
Underground mining (soft rock) Underground mining (soft rock) Underground soft rock mining is a group of underground mining techniques used to extract coal, oil shale, potash and other minerals or geological materials from sedimentary ("soft") rocks. Because deposits in sedimentary rocks are commonly layered and relatively less hard, the mining methods used differ from those used to mine deposits in igneous or metamorphic rocks ("see Underground mining (hard rock)"). Underground mining techniques also differ greatly from those of surface mining. The number sign, or hash sign (#) is often used as shorthand to denote shaft or seam, as in 4# (4 shaft or seam