| 41. | As coal mining expanded villages were built to house coal miners.
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| 42. | Underground coal mines can be equipped with permanently installed sensor systems.
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| 43. | It was initially designed to pump water out of coal mines.
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| 44. | Silk manufacturing and coal mining were once practiced in the borough.
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| 45. | Despite the tragedy, Sysuyev said the coal mine will remain open.
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| 46. | He began work in a coal mine from an early age.
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| 47. | Coal mining was shrinking as oil became the main energy source.
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| 48. | Miners who worked in British coal mines after 1954 can apply.
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| 49. | Coal mining in Coedpoeth is documented from the early 15th century.
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| 50. | Coal from the Pontesford coal mines travelled in the opposite direction.
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