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Room and pillar mining was one of the earliest methods used, [3] although with significantly more manpower. The room and pillar system is used in mining coal, gypsum, [4] iron, [5] limestone, [6] and uranium [7] ores, particularly when found as manto or blanket deposits, stone and aggregates, talc, soda ash, and potash. [8]
Retreat mining is the removal of pillars in the underground mining technique known as room and pillar mining. In the first phase of room and pillar mining, tunnels are advanced into the coal or ore body in a rectangular pattern resembling city streets. Pillars are left between tunnels to support the weight of the overburden. The first phase is ...
Room and pillar : Room and pillar mining is commonly done in flat or gently dipping bedded ore bodies. Pillars are left in place in a regular pattern while the rooms are mined out. In many room and pillar mines, the pillars are taken out starting at the farthest point from the stope access, allowing the roof to collapse and fill in the stope.
I propose that Retreat mining be merged into Room and pillar. As far as I can tell from the present article retreat mining, retreat mining is just a stage of the room and pillar system. As it is, both articles are also short enough that they could be served by a merger. If anyone knews anything that would change this impression, please say so.
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 ...
to get information about the economy of ancient Sri Lanka; to get a knowledge about the evolution of the language and the letters; to get other cultural records; to know different symbols used for different purposes; to know sinhala grammar; to know the names o the kings, rural kings and princes; to know the designations of the royal officers
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