Question

Which type of mining is likely the least harmful to the environment?

Answer 1

let first  take look at this , all types of mining will bring negative impact for environment, but C. Subsurface mining less harmful to the environment because it happens underground before we even do this type of mining we make guidelines that will help us in doing this . Surface mining: Will cause contamination of soil and groundwater which may lead to loss in biodiversity. placer mining will also affect our aquatic ecosystem.

Answer 2

It would be placer because you are not digging up any ground..if that is not right it might be none because if you are messing with water environments you are still messing with it which could not be good