Mining efficiency is your main mining stat. It determines successful mine chance and affects multi-ore drop chance. Also, the higher your mining efficiency is compared to the efficiency required to mine the rock, the more Ore you'll get from each drop (see table below).
Required efficiency can also be found in the AFK info in the game, and is the number underneath the 5% in the bottom left.
Mining efficiency is increased with mining power, which you mainly get from pickaxes, as well as your STR stat and mining level. It can be enhanced further by other bonuses, such as talents, stamps, Alchemy bonuses, and more.
You can access mining nodes from the left portal in the starting town. Note that to access each mining area you need to reach specific thresholds in the mining skill.
The table below lists the required efficiency to be able to mine the ore veins. Note: the 5% value is the absolute minimum value to even have a chance to mine the ore vein. Apart from the Veins, you can also get various other items that you can check on the Ore Vein pages.
If you've ever played Lava's other game Chicken Odyssey you might know what to expect. Except there are no hats and you are not a chicken but a minecart . Tap to jump and tap mid air to dive to the ground. Jump on Ore Nodes to score all while avoiding pits at an ever increasing speed.