Harvest Moon: Back to Nature Mines

Mineral Town has two mines. See what each floor hides, what each ore sells for and which jewels you can find. You need ores to upgrade your tools.

Waterfall Mine

Floors 1-10: Junk Ore, Copper Ore, Silver Ore, Gold Ore, Mystrile Ore, Money Bag (10G)
Floors 5-10: Mystrile Ore (higher spawn rate on lower floors), Power Berry (randomly dug up on floors 5-10, frequently cited on Floor 10)
Floor 10 (Underground Stream): Power Berry, Underground Stream (freshwater fishing spot required for the legendary Char)

Located behind the waterfall basin next to the Hot Springs. Open all year round in all 4 seasons.
Has 10 floors total (B1 to B10). Time is completely frozen while inside either mine in BTN.
Digging with the Hoe unearths ores, money bags (10G), and the hidden ladder to the next floor down.
Ladder spawn rule: Ladders never spawn on the perimeter wall squares of any room. They are often located opposite the entrance.
Bring the Basket (holds 30 items) into the mine to maximize mining haul profits per run.
Digging in the soil on floor 10 (or lower floors) yields 1 permanent Power Berry (+10 max stamina).
The underground stream on floor 10 can be fished to catch the legendary King Fish Char (after learning recipes for Sashimi, Grilled Fish, and Chirashi Sushi).

Floors 1-10: Junk Ore, Mystrile Ore, Orichalcum Ore, Adamantite Ore, Money Bag (10G)
Floors 1-10 (Soil): Ketchup Recipe (hidden recipe dug up from dirt)
Floors 5-10: Power Berry (randomly dug up with Hoe on lower floors, often Floor 9 or 10)
Floor 10 (Underground Lake): Underground Lake (home to the legendary King Fish Catfish)

Located on an island in the middle of Mother's Lake. Only accessible during Winter (Winter 1 to 30) when the lake surface freezes into ice.
Has 10 floors total (B1 to B10). Time freezes while inside.
Orichalcum Ore (50G) mined here is forged by Saibara into Jewelry (2,000G) for a 1,000G fee.
Adamantite Ore (50G) mined here is forged by Saibara into Mayonnaise, Cheese, and Yarn Makers (20,000G each).
Two Power Berries are associated with this mine: one dug up inside on lower floors, and one hidden outside behind the island cave entrance (press Action/X).
Tilling soil inside the Winter Mine can unearth the secret Ketchup recipe.
Floor 10 features an underground lake where the legendary King Fish Catfish can be caught during Winter using the Fishing Pole.
Fishing in the underground lake catches the Catfish, not a Power Berry.