I do quick answers if you don't mind
1. This is solution mining, not underground mining. Basically, they drill 2 holes, 70m apart and pump hot water in (85 degree) and pump out the solution. So basically significant depth is not disadvantage but advantage because it help to keep the heat, also, deeper in the ground-> warmer,-> using less energy
2. I think they will well to get water, and reuse it (80%)
