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Electrical heating elements are lowered into the heating wells and used to heat oil shale to between 650 °F (340 °C) and 700 °F (370 °C) over a period of approximately four years. [2] [6] Kerogen in oil shale is slowly converted into shale oil and gases, which then flow to the surface through recovery wells. [4] [6]
Shale is characterized by its tendency to split into thin layers less than one centimeter in thickness. This property is called fissility. [1] Shale is the most common sedimentary rock. [2] The term shale is sometimes applied more broadly, as essentially a synonym for mudrock, rather than in the narrower sense of clay-rich fissile mudrock. [3]
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. [1] Because deposits in sedimentary rocks are commonly layered and relatively less hard , the mining methods used differ from those used to mine deposits in ...
Soft formation rock bits are used in unconsolidated sands, clays, and soft limestones, etc. Medium formation bits are used in dolomites, limestones, and shale, while hard formation bits are used in hard shale, mudstones, granite, limestones and other hard and/or abrasive formations. Soft ground drilling can be undertaken using a rotary auger or ...
Oil shale is mined either by traditional underground mining or surface mining techniques. There are several mining methods available, but the common aim of all these methods is to fragment the oil shale deposits in order to enable the transport of shale fragments to a power plant or retorting facility.
Oil shale mining reduces the original ecosystem diversity with habitats supporting a variety of plants and animals. After mining the land has to be reclaimed, process takes time and cannot necessarily re-establish the original biodiversity. [3] [4] The impact of sub-surface mining on the surroundings will be less than for open pit mines ...
The newly exposed shale on the cut face weathers rapidly, allowing air and water into the unexcavated rock, resulting in acidic surface runoff after precipitation events. [140] Acidic runoff disrupts aquatic ecosystems , and highly acidic soil contaminated by this runoff will not support vegetation, which is unsightly, and can lead to problems ...
Chipping Sodbury Tunnel ventilation shaft Swan St. ventilation shaft on the Burnley Tunnel Ventilation shafts of the Velser tunnel, the Netherlands. In subterranean civil engineering, ventilation shafts, also known as airshafts or vent shafts, are vertical passages used in mines and tunnels to move fresh air underground, and to remove stale air.