The basic idea is to match each ore type to specific mine depths so copper's gonna be levels 2-39, iron shows up 41-79, and gold appears from 81-119 with the sweet spot around floor 101. Watch the timing on ore nodes, they'll flash briefly before breaking and always target those copper iron or gold-colored rocks since they're guaranteed drops. Your best window for mining is actually during rainy days, when you can skip crop watering and dump that energy into the mines instead.

Getting your gear sorted is pretty crucial, you'll want that copper pickaxe minimum for iron nodes and definitely grab the steel upgrade before tackling gold. Bring plenty of food like cheese or salads, and maybe interesting to pack some bombs for clearing bigger areas quickly. The miner profession at level 5 is basically required, giving you that extra ore per node which really adds up.

For maximizing gold runs, work floors 81-85 then hit the elevator to reset, and time your runs with lucky lunch plus that special charm on high luck days. Dust sprites in the iron levels are actually great for coal farming, and don't forget about checking the quarry once you've got it unlocked through the community center. Quick tip about staircases though, save those mainly for skull cavern runs since the regular mine elevator works every 5 floors anyway.