Go to the planet where you found Aldous/Mr.X. Get out of the ship and go forward until you get down the earth stairs. Then, go straight down. Use your Child Spectrobe to scan the ground in the first corner. You will find four mineral spots. Get them both. Next, go between two piles of rubble in the same place. Again, there are four mineral spots. Stay in this map, and do not go into the mountain area. A lot of valuable mineral are here.