Itznotyerzitz Mine is in Mt. McLargeHuge. If you had some Mining Gear, you could do some mining here. If your main stat isn't high enough, you will see the following message, unless you are wearing Mining Gear:
As you near the Mine, your knees get weak -- you appear to have developed a sudden fear of depths.
(You must have at least 53 <Stat> to adventure here.)
Note: This adventure is sometimes triggered by adventuring here with a ten-leaf clover in your inventory.
In Disguise
Enter Itznotyerzitz Mine
"Dressed in your Mining Gear, you stride past the 7-Foot Dwarves who guard Itznotyerzitz Mine. You walk deep into one of the shafts, and find a nice, quiet place to mine."
Adventuring here with a ten-leaf clover (when not in disguise) will give you either the Either Ore adventure (less likely) or the A Real Gem adventure (more likely).
Itznotyerzitz Mine, when pronounced, sounds like, "It's not yours, it's mine."
The 7-foot dwarves are no doubt partly a play on the seven dwarfs. It is not a reference to the movie Happily Never After, which actually came out after their insertion into the game. Furthermore, it is simply quite ironic to have a 7-foot tall "dwarf," when the word typically indicates someone shorter than usual.