Around floor 60 iridium nodes become plenty, that's where your prismatic hunt begins. Skip infested and unworthy floors. I only bring about 100 bombs, most of stone clearing is by napalm ring. My sword is crusader and the hammer is bug hunter, pretty much what you need to counter every enemies in skull cavern. Lucky day + spicy eel + ginger ale makes you find stairs / shafts pretty quick.Wow, how many stairs did you need to get to level 170? At what level do you stop using stairs and start bombing?
I accidentally made it to floor 65 or something the other day. So many mineshafts x.xFloor 35. My best. And I remebered to take food