1. The quality of raw oil from these tar sands is very poor, so it is necessary to refine this oil extensively before it can be used. Middle East oil, on the other hand, is very "pure" in that it does not need to be refined very much to make it usable.
2. While it is true that Suncor has been able to prefect the tar sands extraction process over the last few years, it is only a matter of time before geological reality starts to have a negative impact on the cost of extracting the oil. These tar sands are located in a deep, diagonal seam in the earth's rock layers, and the oil that is currently being extracted is from the shallowest part of one end of this seam. As this oil is depleted, it will become necessary to either drill through progressively deep layers of rock to get to the oil or develop a method of drawing the oil out through some kind of directional digging process. The thing you have to remember is that this oil is not drilled (as it usually is), but mined, so the directional drilling that is used these days will not help.
On the other hand, I am quite confident that Alberta has tremendous potential to serve as a long-term energy source for the U.S. (not just oil but coal, which is abundant along the eastern slopes of the Canadian Rockies). For one thing, this province is very forward-thinking and pro-business, and I expect that innovative extraction and refining techniques will be developed here over the coming years. In addition to that, oil and natural gas extraction plays such a vital role in the economy here that many of the standard land use approvals are waived, by law, for projects in these areas.
To top it all off, and to answer some other questions here related to the environmentalists in Canada, there isn't a place in Canada, if not all of North America, that is more antagonistic to environmentalists when their objectives cause problems in the local economy. Even PETA pulled all of their billboard and radio ads up here this summer, in response to some veiled threats from the cattle industry. The Alberta Beef Industry had started their own anti-PETA campaign, with the following slogan:
"Save a cow ... Eat an environmentalist!"
Albertans do have a sense of humor.
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We were working on several different solutions to this type of problem, and had several 'model' solutions we were working on in the early 80's. No more mining, but some drilling and other stuff.