I think you need to look at which impact you're concerned about. You need to partition them, I think, a little bit. The impacts that I see are on land and land reclamation, water use and tailings, energy use and greenhouse gases.
The first two I think are much more amenable to regulation and getting the industry to speed up reclamation and to minimize the accumulation of tailings. The greenhouse gas issues I think are much less amenable to relatively painless regulatory implementation because the technologies that are available for dealing with carbon dioxide are significantly more expensive.