Question: how much energy does it take to destroy a mountain?
Answer: Violent Fragmentation: Mountain level (4.184e17 Joules) / (69 Joules/cc) = 6.064e15 cm^3, or 6.064e9 m^3 destroyed. Assuming that the mountain's height and radius are equal, the minimum values for both radius and height should be about 1795.72m.