| 1. | They followed the ore veins underground once opencast mining was no longer feasible.
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| 2. | Black powder allowed blasting of rock and earth to loosen and reveal ore veins.
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| 3. | Monazite from certain carbonatites or from Bolivian tin ore veins is essentially thorium-free.
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| 4. | In geology, Agricola described and illustrated how ore veins occur in and on the ground.
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| 5. | Similar tunnels, known as drifts, are driven along the ore veins from the crosscut.
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| 6. | At first, the mines were open cast, because the ore veins were on the surface.
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| 7. | A newly elected labour government presented higher anticipated union costs and the ore vein had already been'highgraded '.
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| 8. | Minerals in the silver-ore veins include polybasite, pyrargyrite, proustite, sphalerite, galena, and tennantite.
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| 9. | Mining started in 1523 with " Bauernzeche " pit on the ore vein " Bauer Morgengang ".
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| 10. | Near the head of the gulch is an ore vein ( reported in 1955 ) containing chalcopyrite, galena, pyrite, and calcite.
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