I have been compiling some statistics on what the yeild is for various mining combinations and thought I would share:
Human Miner Not Prospecting: 83.4% Iron Ore, 16.6% Colored Ore. This is a result of hitting iron veins 50% of the time, and pulling in colored ore 33.3% of the time on colored veins. Colored Ore spread per random occurrence variables available here:
http://uo.stratics.com/content/skills/mining.phpHuman Miner Prospecting: 66.6% Iron Ore, 33.3% Colored Ore. This is the result of human 1/3 yeild on colored veins and converting all iron only veins to dull copper veins and promoting all colored veins aside from valorite one color.
Elf Miner Not Prospecting: 75% Iron Ore, 25% Colored Ore: This is the result of hitting iron ore veins 50% of the time, and the Elf bonus which bumps the yeild on colored veins to 50%.
Elf Miner Prospecting: 50% Iron Ore, 50% Colored Ore: This is the result of converting iron ore veins to dull copper, promoting all but valorite veins one colore, and the Elf bonus which bumps the yeild on colored veins to 50%
Conclusion:Most of the mining I have been doing in UO has been on human miners that were not prospecting. I have no trouble getting iron, but often run short on colored ingots. By converting all of my miners to elves and prospecting 100% of the time I can more than triple my colored ingot yeild.