My guess is what it will do to copper prices, partucularly scrap, Is absoloutley nothing at all.

Like every commodity, it will rise and fall according to market forces beyond one mine. The biggest thing to remember is these articles are always Hyped to the eyeballs to see newspapers and attract investors. They are never as wonderful as they make out.
If you look at the way business operates, like oil they will regulate production to keep both demand and prices high. They are not going to flood the market and only get half what they could for their product, they will produce enough to keep the price where they want it and fulfill the orders they get without allowing the price to fall. Simple economics.

I like the bit in the article that said the mine can fulfill 25% of Americas copper needs for the next 40 years. They could have said will supply 1% of Chinas copper needs for the next 12 months but that wouldn't sound nearly as good would it? :0)
Manufacturing in the west is dead and buried so worrying about the needs of a western country is like worrying about the gold fish having enough water when dying of thirst. Even if a mine will put a dent in a countrys needs, it's a global market and they are not going to flood it and drop prices which will result in lower returns on their own investment even if they had the ability, which they do not.



In any case, will probablky take 5-10 years before the mine comes on stream enough to make a difference and the demand will have risen enough but then to make prices even higher and supply harder to get.