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[4] [6] [7] Water is then removed from the working zone. Heating and recovery wells are drilled at 40 feet (12 m) intervals within the working zone. 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.
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 ...
Water concerns are a particularly sensitive issue in arid regions, such as the western part of the United States and Israel's Negev Desert, where there are plans to expand the oil shale industry. [9] Depending on technology, above-ground retorting uses between one and five barrels of water per barrel of produced shale oil.
In this way, given certain conditions (which are largely temperature-dependent) kerogens will break down to form hydrocarbons through a chemical process known as cracking, or catagenesis. A kinetic model based on experimental data can capture most of the essential transformation in diagenesis, [ 10 ] and a mathematical model in a compacting ...
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 ...
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 ...
The water was used for a variety of purposes, including removing overburden and rock debris, called hydraulic mining, as well as washing comminuted, or crushed, ores and driving simple machinery. The Romans used hydraulic mining methods on a large scale to prospect for the veins of ore, especially using a now-obsolete form of mining known as ...