Dry stackable means that you don't need containment. It means you can put them anywhere; they will not flow. You can then reclaim the areas if you have this solid surface. That's the difference between that and the tailings ponds, where you have to contain them. With dry stackable, the definition is that you don't need a containment system.
In terms of what you said about their just going higher, to do that they need sand, and often that's an issue. They just don't have enough sand to build up these dikes higher and higher. It's a numbers game. It's a very complex system they have to manage. There's the amount of sand they need to build dikes. They don't have enough sand. They're running out of area. So they need another method. Hence, they're going to the technologies that--