"The Story of the Star Valley" Which layer of iridium mine has the most tips?

There will be more iridium mines below the 30th floor, but this is only relative. Because of the time limit, you'd better check your luck before going out. If you are lucky, take some lucky food, some medicine and more bombs, plus a slat (for safety reasons). Because of the time, it is impossible to get to the 30th floor before 12 in the afternoon unless a lot of stairs are made. If you are lucky, you can blow it up.