Please note that in order to complete the Master Mine without using a Cheating Pickaxe you will need at the very least the Fantastic Hammer, which you can buy from the shop after expanding the house a second time. Also be aware that this is only to reach the "clear" room and not either of the Rare Token ores in the back rooms of the caves.

In the Master Mine, please note the three areas that make up the mine: the "Central Area", which contains a large boulder requiring 15 pickaxe power blocking off a chest, gold, and "Clear" icon; and the "Left Cave" and "Right Cave" respectively, accessed by the doorways on the left and right sides of the Central Area. Below is a picture for aiding in following the steps detailed further below.



1 - Starting in the Left Cave, destroy two of the three gray rocks (labeled a) to gain passage to the two Pickaxes and grab them both.
2 - Now over to the Right Cave, destroy the two gray rocks (labeled b) to grab the Wooden Keys behind both.
3 - With the two Wooden Keys in hand, unlock the two Wooden Doors blocking the path to the right side of the room, giving you access to two Pickaxes to grab.
4 - On the mirror part of the cave, the left side has three mini-Energy Fruit guarded by two Wooden Doors and two black rocks. Demolish the two black rocks and refill your energy with the three fruit.
5 - Return now to the Left Cave, and break down one of the four black rocks protecting a Wooden Key, and grab it.
6 - In the same room, use the Wooden Key to unlock the door with the Red Key behind it and grab it. Go around the corner and unlock the Red Door to gain access to the upper portion of the room. Do not let the two Wooden Keys tempt you yet.
7 - In the upper-left corner of the room you can clear out the lone black rock to reach the two Pickaxes, mini-Energy Fruit, and one Wooden Key.
8 - Remember those two keys that I said not to be tempted by? Since you're still here in the Left Cave the Wooden Key you just grabbed can be used to open the back door to them. With those two in your possession, we move to the Right Cave.
9 - Clear the line of nine Brown Rocks blocking the path to the Red Key.
10 - With that new key, take it to the bottom-right corner of the room, opening it up to snatch up another mini-Energy Fruit and Pickaxe.
11 - Return to the Left Cave once again and break the remaining three black rocks (labeled 11a, 11b, and 11c) to grab three Wooden Keys. You should have five of them in your possession at this point.
12 - Five keys in hand will allow you to open the line of doors in the upper-right corner of the room to grab the lone Silver Key.
13 - Use the Silver Key on the Silver Door in the bottom-right corner of the room to nab another mini-Energy Fruit and four Pickaxes.
14 - Go back to the Right Cave and go clear out the remaining line of nine brown rocks in the upper corners of the room to pick up the last Red Key in the mine.
15 - Open the Red Door in the bottom-left corner of the room to grab the mini-Energy Fruit and final Pickaxe of the mine.

Finally, return to the Central Area to break the giant boulder.