Sorry, R Traveler, but the 60/40 & 40/60 stuff has been conclusively disproven for mining.
It actually appears that there is some sort of older code that the current devs have no knowledge how it works, that the Devs applied their "20% elven bonus" to.
Extensive testing has shown that every resource square has its own, INDEPENDENT, iron to color ratio chance, that does not change through ore type changes (And comes into play even for iron sites, when elevated with tools). Spots I've tested with a human that routinely give 70% colored ore, ALWAYS give approximately that much, and spots that give 5-10% at best, always stay nearly all-iron (which my 2 sets of books helped me test, after the ore randomization). The 40% colored figure for humans given by the current devs seems to be pulled out of someone's nether regions, or at best based on designer notes that never made it into the game, by someone that was long gone before Age of Shadows. It may be that the 40% was the center point of the RANGE that ore sites might give colored ore, when generated initially (and the number generated becomes permanent), but it's not a flat 40% per resource square.
I've personally got several spots marked in books, that I no longer use (I prefer mining mountainsides, rather than recalling around, after the ore change), that routinely gave my human 85%+ colored ore, 20+ digs per trip, for a test of 10 or more visits, regardless of what the vein's base material was before I used a prospector's tool on it. That shouldn't be possible if a human only has a 40% colored ore chance.
And, that if the Elf bonus works at all, it multiplies the colored ore percentage by 120% for a "20% bonus", resulting in a 10% colored node becoming a 12% colored node, and a 70% colored node becoming 84% colored. Still a significant bonus, but not 150% of a human's color ore output (and made less effective over time by the human getting 10% more total ore).
It seems to work as stated for LUMBERJACKING, but that system was created from scratch by the developers that describe it. On the other hand, we all know too well about misunderstandings concerning legacy code (Tailor BODs being 33% exceptional for 6+ years, after all the dev statements had said 50%, for example; or the yes/no/yes answers on the Samurai's Perfection luck bonus, because the dev that coded it put the calculation someplace later devs never thought to look, until they found it by accident a year after they claimed it didn't exist, and must have not made it out of the SE beta).
