| 11. | The explosions caused severe damage to the underground workings.
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| 12. | Ore was extracted from underground workings until 1915, when a small open pit was dug.
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| 13. | There are about 20 miles of underground workings.
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| 14. | The hill is " honeycombed " with underground workings, reaching from the summit to depths of.
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| 15. | Complex arrangements were written into the leases to ensure that the underground workings did not conflict.
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| 16. | The land above the underground workings, together with the surface quarries, became a National Nature Reserve.
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| 17. | Between 1975 and 2000 the lease to the underground workings at Dolaucothi was held by Cardiff University.
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| 18. | The underground workings were deepened and the crown corporation sought out additional deposits of uranium across Canada.
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| 19. | Idarado kept the underground workings and mill operations open at Telluride s Pandora hard-rock mine until 1978.
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| 20. | Just after 8 : 00 am an explosion occurred in the west side of the underground workings.
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