The statement "Both types of mining cause high risk of sediment runoff" is true regarding the potential environmental impact on local water by both surface and underground mining.
Both surface and underground mining operations can disturb large areas of land, which can lead to erosion and sediment runoff into nearby waterways. This runoff can carry pollutants and sediment, affecting water quality and aquatic habitats. Other issues associated with mining, such as acid mine drainage and changes to the water table, can also occur, but sediment runoff is a common impact associated with both methods.