I want to suggest to add a piston movable block that outputs a redstone signal when a ore vein is nearby.

Running around with the stick works, but it is quite tedious for larger areas in my opinion.

Maybe it could output the type of vein with a comparator too.

I don't know if a comparator is a good idea, since there might be more than 15 ore veins. Given that this is still a Create addon, i'd put that kind of output in the goggles interface.

You could also create a new block, such as a sonar, that uses rotational force and some other element to locate the veins in the specific chunks, for it to work you would have to introduce books so that when you find one that writes the location on it and what is.

Another method could be a kind of hammer that hits the ground (that's why it needs rotational force) and that, depending on how it detects the waves, vibrations, etc. Know where there is a vein and what mineral it is