With the best mining skill (5), it takes 7 energy to mine around 6-10 ores of a material. If you're mining with other players, you can easily make an extra 1-3 ores. So, it's easy to say that a character with max'd mining skill can get ores on a 1:1 energy:ore ratio.
Crushing on the other hand takes an insane amount of energy to do. It takes 4 energy, 3 energy with refining 2, PER ore to crush. So it takes 200 energy (150 energy with refining 2) to crush a stack of 50 ores. The ratio is 4:1 energy:ore crushed.
Why is it so much? My guy is level 16 and has 390 energy. I can crush around 125 ores (2 stacks of 50, 1 stack of 25) and it will consume all my energy. I can possibly meditate back up to 200 (i'm not sure of the daily limit) and use 5 medalions for another 100 energy, but that's still just 2 more stacks of 50 ores. I would be lucky to be able to craft a single set of Extremely Hallowed Shrine Powder with all that.
Again, why is it so much?