I'm writing a book that's set on a planet very similar to earth, meaning it has all the same gravity, mineral compositions, and geologic features. With that in mind:
What geological features are the best to mine/find what minerals? I.e. what terrain (low hills, inactive volcanos, sedimentary rock, new mountains, along tectonic plates) would important materials be found in? (the main ones I'm curious about are gold, silver, copper, iron, jade, and diamond).
How close to the surface would/could these materials be? I.e. is it possible to find the materials listed above without mining for them? If so, under what circumstances would they be found (erosion, volcanic activity, etc.).
How close could veins of certain materials be to each other? I.e. is it possible to have a mine that mines for iron, copper, and gold, or would there be regions in which people could only mine gold or only mine iron? If the latter is true, how close could these areas realistically be?
This is my first question, so feel free to correct the way I phrased things or ask for clarification. Thanks!