Ore is picked with a chance shown in the table till New Zulu. Higher Ore starts from New Zulu. You don't have to pick it, it is found like maps. Using Omera you won't be picking 2 pieces of ore at once. Moreover, your chances for success won't increase. A Crafter can obtain New Zulu if he matches the requirements: Crafter is at least 3 game level, Mining skill is 115+, Paradise 120+, Hell 125+, Void 130+. Crafter needs a bit lower Mining skill level if he is 4 game level.
The table of items requirements
Table