I think you should be able to build mines like normal, instead of prospecting and searching. All mines would require Rustroot, and Prospecting skill, but mines found with prospecting and searching as it is now give ore with no quality under 30, usually more. Mines built from the build menu will always have base quality 10, and .2 quality for every mining level, and .01 for every space away from the center of the mine you are. Not very good. Also, they only come in iron. These mines would require only 100 wood blocks, but there is a chance of cave ins when mining. When the mine is built, there is 1 space around the ladder in every direction. Very close in. Big rocks would be everywhere, prohibiting you from mining there, encouraging tunnels instead of a big cavern. Cave ins would be signaled by your screen shaking, and if caught in one, you will be knocked out, and half of your hhp lost. To stop cave ins, you can build supports. Supports require 1 wood board, and would prevent cave ins 5 spaces around the support. You can get rid of rocks from cave ins by mining them, which will drop 30 rocks on the floor scattered about.
This would let you build crappy, dangerous, low quality mines, but it would be worth it because metal is not a big commodity any more, but tin, bronze and gold is extremely rare, and is high quality iron. Thanks for reading!
TL;DR
Suck it up and read the essay boi.