When.com Web Search

Search results

  1. Results From The WOW.Com Content Network
  2. Coal - Wikipedia

    en.wikipedia.org/wiki/Coal

    Coal is a combustible black or brownish-black sedimentary rock, ... For example, the mining of coal affects groundwater and water table levels and acidity.

  3. Sedimentary rock - Wikipedia

    en.wikipedia.org/wiki/Sedimentary_rock

    Uluru (Ayers Rock) is a large sandstone formation in Northern Territory, Australia.. Sedimentary rocks can be subdivided into four groups based on the processes responsible for their formation: clastic sedimentary rocks, biochemical (biogenic) sedimentary rocks, chemical sedimentary rocks, and a fourth category for "other" sedimentary rocks formed by impacts, volcanism, and other minor processes.

  4. Underground soft-rock mining - Wikipedia

    en.wikipedia.org/wiki/Underground_soft-rock_mining

    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 ...

  5. Seatearth - Wikipedia

    en.wikipedia.org/wiki/Seatearth

    Seatearth is a British coal mining term that is used in the geological literature. As noted by Jackson, [1] a seatearth is the layer of sedimentary rock underlying a coal seam. Seatearths have also been called seat earth, "seat rock", or "seat stone" in the geologic literature.

  6. Illinois Basin - Wikipedia

    en.wikipedia.org/wiki/Illinois_Basin

    Within the basin, deposits valuable for lead, zinc, coal balls and fluorite are mined in Hardin and Pope counties, Illinois, and Crittenden and Livingston counties, Kentucky. the deposits are in the form of veins and limestone replacement deposits in Mississippian sedimentary rocks. Ore minerals are fluorite, galena, and sphalerite.

  7. Coal mining - Wikipedia

    en.wikipedia.org/wiki/Coal_mining

    A coal mine mantrip at Lackawanna Coal Mine in Scranton, Pennsylvania Coal miners exiting a winder cage at a mine near Richlands, Virginia in 1974 Surface coal mining in Wyoming, U.S. A coal mine in Frameries, Belgium. Coal mining is the process of extracting coal from the ground or from a mine.

  8. Lignite - Wikipedia

    en.wikipedia.org/wiki/Lignite

    Lignite (derived from Latin lignum meaning 'wood'), often referred to as brown coal, [1] is a soft, brown, combustible sedimentary rock formed from naturally compressed peat. It has a carbon content around 25–35% [ 1 ] [ 2 ] and is considered the lowest rank of coal due to its relatively low heat content .

  9. List of rock types - Wikipedia

    en.wikipedia.org/wiki/List_of_rock_types

    Claystone – Clastic sedimentary rock composed primarily of clay-sized particles; Coal – Combustible sedimentary rock composed primarily of carbon; Conglomerate – Sedimentary rock composed of smaller rock fragments; Coquina – Sedimentary rock that is composed mostly of fragments of shells; Diamictite – Type of sedimentary rock