[estelle]

But if past trends are anything to go by, technological advancements will mean that deposits of ever decreasing grade will continue to become economically viable to extract.
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By the same token, the advancing technology could also see the present difficulty with asteroid/space mining become more realistic to undertake.

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Also, if we could get to the point where metal extraction from sea water is viable, we'll likely not need to go looking elsewhere.
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That's also a possibility for the future, but I don't believe we would need to look too far in our solar system for desired elements.


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I agree, never is a long time... but most of my posts have been limited to the 'foreseeable future'.
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Never say never...And "forseeable futures" are fairly undefined.