Well, out of randomness I feel like getting 80 Mining.

 

If I'm not mistaken granite is still the fastest way, but I'm not one for concentrating that much on dropping granite as fast as you can.

 

 

1. Is granite still faster than Iron at the monk fish place (Forgot exact name) and banking it with dueling rings if you're not concentrating that much on dropping the granite as fast as you can?

 

2. Should I switch to concentrated coal at 77?

1. It likely is. If all your going for is 80 mining, I'd go right ahead and do iron anyways. Make some decent gp, because the couple of k exp per hour won't make a huge difference by level 80 anyways.

2. I'd say yes. I'm not sure exactly about exp/hour rates, but it's more gp, and less effort!