I excavated a wide hill a long time ago.

And here is me doing it to a mountain.

And now I'm doing it on my friend's realm but on a MUCH taller mountain.
I excavated around 10 layers of the mountain
I didn't take a picture of the mountain when I started but here is one I put into the realm feed

I used up 11 iron pickaxes and 9 iron shovels so far.
On a side note,

I found I think the 5th rarest biome in minecraft yesterday.
A tall birch forest.