Tutorial is up to date with r011.
For successful mining, you need a workshop and a treasury. This tutorial assumes that you know how to order your imps to excavate new rooms and corridors.
So, order your imps to excavate a 2×2 area, and use the „saw and hammer“ icon to change the tool to create workshops. Now you can click the floors of the new area, and they will be converted to workshop squares. Afterwards press the right mouse button, to revert the command tool to „mark for digging“.
Then, let the imps excavate another 2×2 area, and use the „treasure chest“ icon to create a new treasury, like you did with the workshop. Afterwards press the right mouse button, to revert the command tool to „mark for digging“.
Then dig corridors towards a mound of copper ore (the ones with the blue veins) and a mound with tin ore (the ones with the black veins). Click each of the mounds. A mining symbol like on earth squares will appear there, but smaller. An Imp will come to each mound and start digging. Unlike earth, the mound won’t collapse immediately, they last a while. The imps will break out lumps of ore and bring them to the workshop.
You can order up to three imps to work on a resource mound, by clicking the mound several times. The fourth click will unmark the mound, and the imps will stop digging there.
Conians occasionally work in workshops just for fun. You’ll have to wait until one decides to work. It will go to the workshop by itself and start working there, converting the ore to bronze coins.
Once there are coins, sooner or later one of the Imps will come and carry the coins to the treasury.