ok, the requirements for this are 2 things.
1. cheat engine with mountain climbing hack
2. a mount or anything that can get u to at least +60% speed
ok, this is my first try with a guide and using pics, so tell me how im doing
start at the left side of van cleefs cavern door and climb up the mountain
then follow my arrow to pic number 3
heres where u need the speed boost, JUMP off with a mount or speed boost, and try to aim for the closest water
this pic shows how u should have jumped off, and the direction ur going to go
and finally, after about 45 secs, ull get to the white box and c the mountain
and there u go, ur at the deadmines secret!