| 11. | The open-pit mining of porphyry copper deposits was adopted worldwide.
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| 12. | In the batholiths there are quartz-feldspar porphyry and dolerite dykes.
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| 13. | Mineralization occurs within the Laramide intrusive and in the surrounding Precambrian porphyry.
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| 14. | The entire island constitutes the Porphyry Island Provincial Park or nature reserve.
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| 15. | The quarry also features a very thick intrusion of porphyry.
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| 16. | The fa�ade is covered with marble, strips of porphyry and verd antique.
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| 17. | Most are ground from grayish green, banded slate, and occasionally porphyry.
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| 18. | Porphyry may also have been present at this meeting.
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| 19. | It is believed that tectonic change acts as a trigger for porphyry formation.
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| 20. | The intrusive quartz-porphyries are equally well described as granite-porphyries.
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