Some time ago, perhaps over a year, a screenshot was posted on the forum by Unana showing ore that had exploded all over a room from a critical hit from a heavy pickaxe. Due to this screenshot being posted, mining was rebalanced. However, it has since been discovered that what had transpired in that picture was actually a glitch: stacking an alchemist's fire and any on-hit spell effect (in the case of Unana's Sivius, it was darkfire) would cause a rock to explode with ore. This bug has since been fixed, but the mining rebalance (nerf) remains.
I would hope that mining could be placed back to how it originally was, but it should at least be looked at. Right now, mining is supposed to be a damage/strength based endeavor, but I hardly find that to be the case. My barbarian has 22 strength and improved power attack. Here is a video of me mining only three ore:
http://www.xfire.com/video/247872/Every time I travel, everyone seems to mine more than I do, but stat-wise, my character should be the ideal miner. I use a pickaxe, improved power attack, and sometimes rage/bull's strength, but I get assy amounts of ore, generally in the range of 0-6 per ore-rich rock. I see people mining with a pickaxe in each hand, elves with 10 strength, or people whacking the ore-rich rocks with weapons like halberds and fists, and they generally end up walking away with more ore than I do per rock.
It's sad to spend a lot of time in the silver mine only to end up getting a few nibbles of ore per rock, when your character is as focused as can be at mining, and has the right tools for the job.
Please reconsider the mining values.