From Harvest Moon - Wiki on Neoseeker

Mining is a quick way to earn money. You can mine in the Excavation Site. There are 4 unopened mines once you start the game. You will usually find Flora and Carter in there. And sometimes Gray on Thursdays if you connect with your copy of More Friends of Mineral Town. At the start of the game you can visit their site and use your hoe to dig up such items as Dresses, Brooches, Earrings, etc.

Perfume only appears in Year 6

First Mine

To unlock the first mine:

• Have your hammer equppied
• Go to the excavation site in the early morning or the late night. [Hours when no one is there]

There ill be a short cutscene in which Carter asks walks in and you open the mine with your hammer.

This mine has only 10 floors.

In the Ground: Black grass - All floors - 10G

In the Stones: Junk Ore - All floors - 1G Copper - All floors - 15G Silver - All floors - 20G Gold - Floor 3 and below - 25G Mystrile - Floor 6 and below - 40G

Creatures: Dark Chick - Floor 10 - 5 HP