In Elex, you have an option to gather resources – you can mine various deposits, e.g. Elexit or iron. This is a way of getting additional Elexit or crafting materials.
In order to start mining you will need a tool called Jackhammer. The easiest way to get it is to take it from location called The Pit located in Goliet (more information about The Pit can be found in FAQ section – How to reach The Pit in Goliet?). If you have this hammer then you can start searching for deposits – they are scattered around the entire planet but the most of them can be found in caves and near bases of mountains or rocks. Mining ability is helpful during this process. Each level increases amount of acquired minerals.