Mining Skill allows you to obtain metal Ores and Gems from rocks. Ores can be turned into bars using the Smithing Skill or sold for profit. Mining is one of the most popular Skills in the Game, and for a good reason. When leveled high enough it can be used for making a lot of Gold...
Farming is basically growing crops and harvesting them for useful items using your Runescape Account. Normally, players will harvest the plant itself, instead of letting the crops bloom fruits. There are many kinds of plants that a player could plant, including: vegetables, fruit trees, herbs, ...