Lets say the player has the prospecting skill but doesn't have the necessary (and joker-insane i might add) stats to find a rust root. In order to avoid making the prospecting skill completely fucking useless until hour 24xx of gameplay (lets face it, it is useless until you find a rust root, just like swimming skill w/ <90 constitution) let the player go into a natural cave and use the prospecting skill on the stalagmites there. If the player finds ores, then they can mine the stalagmites for that ore, with there being at least 1 ore of the discovered type in that stalagmite out of all the rock that comes from it. Obviously, ore qualities can be limited to a fraction of the nearest mining point.
- Player enters cavern, lights torch/camp fires.
- Player locates and prospects whatever stalagmites there are.
-- Stalagmite that "has ores" in it can give out at least 1 ore when mined. (no stupid false positives)
- Player is happy that his prospecting skill is no longer considered a complete waste of his time, and has at least something to show for the 5000 experience he spent on it.
tl;dr
Prospecting is useless until you hit 63/64 perception and 64/63 exploration. This idea makes prospecting more useful then it currently is without such stats, but not as useful as with those stats.
[edit - this is not a gripe of "where's my iron?!" it is a gripe that there is a useless skill sitting on the tree that costs 5000 experience, and is not immediately useful without the use of secondary stats, AND AN ITEM THAT IS RARE AND IN HIGH DEMAND. 5000 xp more then enough to buy a good deal of the starting skills, all of which are much more immediate in their impact on the players' abilities. If the stat requirement for prospecting to function were removed and item restriction loosened, and the skill cost increase by 10 times, i wouldn't mind it. As long as the skill is immediately useful like most other skills are, it would be fine with me.]