| 41. | The clay is excavated using surface mining techniques.
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| 42. | Underground mining has environmental advantages over surface mining because it tears up less of the landscape.
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| 43. | Limited surface mining resumed in the late 2000s.
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| 44. | Pupation takes place in a separate, lower-surface mine.
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| 45. | Archeologists who have surveyed the mountain say it contains a number of ancient Indian surface mines.
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| 46. | North Antelope Rochelle is a surface mine.
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| 47. | They are too deep to surface mine.
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| 48. | The Railroad Commission also regulates surface mining.
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| 49. | It is threatened by surface mining activities.
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| 50. | The director of the Office of Surface Mining, Robert Uram, was sympathetic once the misunderstanding became clear.
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