You will get 300 Gold and Brotherhood reputation points upon accepting the quest. Once you got the quest, head to Orna Mine. There are a lot of Dwarves in the mine so come prepared for a fight. The Dwarf Leader you must dispatch is in one of the crannies to the left of a larger room. He will most likely come after you once you pick a fight with the other Dwarves in the area. Upon killing the Dwarf Leader, you get 1 skill point and x10 XP. When you speak to Alfron again to complete the quest, you will be rewarded the promised 700 Gold as well as another two point reputation boost with the Brotherhood.