Finish the Snowhead temple, and the mountain will melt down. Go talk to the baby goron to try and join the goon race, there will be a boulder blocking the path that can only be blown with the powder keg, go to the powder ked shop (it's frozen if you haven't beaten the temple or don't have the fire arrows), and the owner of the shop will test you to see if you get one, by seeing if you can (...)