Yeah...
About half your spots will be iron.
Of the rest, they will average 50% colored, 50% iron, so you should expect 75% Iron, unless you use the special mining tools.
Advice for getting more colored ore:
1. fill some exceptional small iron BODs (like weapons) to get Prospector's Tools and Gargoyle Pickaxes.
Using the Prospector's Tool on each site will turn those iron sites into Dull Copper sites, and bump everything else one step, with no danger. This is especially good for collecting Dull Copper & Shadow Iron for BODs*.
Gargoyle Picks do the same, but with the risk of Shadow or higher elementals.
If you can fight the elementals, I recommend using garg picks whenever possible for the extra ore. IF you need Dull Copper, dig once with a normal tool, then use the Prospector's tool. If the end result is Dull copper, go back to digging with the normal shovel or pick. If it's higher (or you want shadow more), start digging with garg picks. The Prospectors tools are so much more common (they last 5-8 times longer than a garg pick), that you don't want to waste potential elemental spawns by using them to dig for dull copper.
2. If you have a set of mining sites, or can mark, go through and start recording what you get (iron vs colored, and total digs per grid section) per each area (remember, everything is in 8x8 grids), for about 10 passes. Remember, to get colored from a spot currently iron, you got to use a PT or GPA
Some spots will produce 10% or less colored ore, consistantly.
Some spots will produce 80% colored ore, consistantly.
Most spots will produce 40% (human, Gargoyle) or 48% (Elf; 40% + 20% of 40%) colored ore, with the human getting an extra ore every so often, and Elves maybe getting about the same number of ore, but from more digs (so it balances out).
You'll also want to concentrate on spots that give 12, 15 or more digs per trip (some get close to 30)
Assemble a few books over time, that average 60% or greater colored ore, and 12+ digs of full-size ore per trip. It may take a few weeks, but when you get it done, and have the tools to make sure you get colored ore all the time, you'll get a lot less iron.
3. For additional Shadow Iron ore, send a character with mining and an orc slayer to the basement of the orc caves, and farm Orc Brutes. Each of them carry as much Shadow Iron ore (25) as a Shadow elemental, and you won't run into hassles farming them that you would at the Yomotsu mines farming Shadow eles (As tamers use the shadow eles there to train their pets, since the pets can't hurt the eles).
*With the amount that Powder of Fortifying is going for these days (I saw SIX vials sell as an auction lot for 1 million gold last night on a small shard like Lake Austin), you'll be wanting to even fill the 20% Powder chance BODs (10 & 15 count EX DC, 20 count normal bronze, 10 & 15 count normal gold) - plus if you run low on gold & agapite, DC & Shadow can be used with the quest pots from Ter Mur to make gold & agapite. The quest for an elixir to turn iron into DC/Shadow/copper/bronze randomly isn't worth the effort of trying to get 10 iron beetle scales.
