From Asda Story Wiki

Mining is a gathering function found in Asda Story. Mining allows your character to dig for items buried underground, and those items you find will vary depending on the area you dig. To mine, you first need a Shovel. Each character is issued a Traveler Shovel to dig with, with other shovels available later in the game. To start mining, double click your shovel or place it on a hot key and click it to start mining. Note: You are not allowed to dig inside of towns (such as Alpen)

Ways to increase your chances in minings are:

• Friendship points earned by being near your Soulmate
  
• Get a better shovel
  

[edit] Shovels

Traveler Shovel - Weight 3 - A lightweight portable traveler shovel used to dig items buried in the ground - Default Shovel

Shovel - Weight 1 - This shovel is used for digging items (acquisitive percentage +1) - 6000 gold from Misc. Shops

[edit] Items from Digging

Here is a generic list of the items that you can get. The actual items that you get from digging depend on the map that you are digging at, with higher level maps giving better items.

Sand

HP Potions

MP Potions

Quivers

Gray Treasure Box

Crossbow Quivers

Ballista Quivers

Sowels

-High Horse Eye Stone

Soul Stones

Sowel Fragments

Jewels

-D-ranked Jewel

Return Scrolls

Revival Scrolls

Great Armor Upgrade Scroll

Great Weapon Upgrade Scroll