Certainly, as supply increases, the price will go down somewhat, although we are already at a fairly low price due to the recession. South Africa's mining issues will probably counter our increase in supply though.
At any rate, the supply won't actually increase until shovels strike the ore, which is still some time down the unbuilt railroad... It will be good for North America though, since the cost of shipping and access to a 'home' mine will ease supply concerns