Mining.

copper(1) 2,170 exp

tin(1) 2,170 exp

iron(15) 3,430 exp

coal(30) 4,830 exp

gold(40) 6,412 exp

mith(50) 8,820 exp

addy(70) 13,384 exp

rune(85) 21,170 exp

star dust(80) 23,021 exp