When mining, you'll find allsorts of things. rocks, minerals, rocks....but this is up to random chance.
Specifically, the random chance of a D2000 die (subject to change). Rolling a single D1000 die will determine precisely what you run into, and if it's avoidable. Generally, mining is helped by having a good skill in mining (obviously), construction, as well as crafting and occasionally smithing to help improvise in certain situations. A low score on the D2000 is not necissarily bad, simply different.
1: May the gods have mercy on your soul. You've stumbled across a ripper demon, entombed in stone. IF you fail a mining check of 20, a prayer check of 15 and a magic check of 15 then you will find yourself face-to-face with a freshly released, hungry ripper demon..
Sometimes a GM may ask for random stat checks.
Perhaps impossibly high mining checks.
But at the end of the day.
There's nothing here but rocks.
1995-1999: You may have gotten lucky. Check mining against a DC22, EXCLUDING the pickaxe bonus. If you succeed, you find hints of a vein of runite. It will take 4 hours' worth of progress total, each hour requiring a DC15 mining check (pickaxe included). There is no penalty for failure, however think of loosing that rare runite because you "needed a breather"...The amount present is ((2D4)/4) of a single ingot's worth.
2000: You lucky git. Runite ore is directly in your path, no mining check needed. The amount present is ((1D4)/4) of a single ingot's worth.