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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.
The archaeological heritage of Sri Lanka can be divided into three ages; Prehistoric (Stone-age), Protohistoric (Iron Age), and historical period. The presence of man activities in Sri Lanka probably dates from 75,000 years ago (late Pleistocene period). Prehistoric sites which are presently identified in the country are distributed from the ...
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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
Thonigala Rock Inscriptions (Sinhala: තෝනිගල සෙල් ලිපිය) are two Elu-language inscriptions engraved on a rock situated in Anamaduwa of Sri Lanka, written in Brahmi alphabet. Each inscription is about 100 feet long and each letter is about one feet in height and engraved about one inch deep in to the rock. [1]
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