A Mining tome is an experience reward from the activity, Temple Trekking. You can get one by taking one of the followers from Paterdomus to Burgh de Rott or followers from Burgh de Rott to Paterdomus. At the end, you will get a Reward token which can be exchanged by clicking on the first option, Claim-reward. The Mining tome grants mining experience once read. The colour of the tome depends upon the level of the reward token. A higher level reward token will give more mining experience.