Goldenrock Mine is a small mine located near Darkwater Crossing. It is under Stormcloak or Imperial Legion control, depending upon choices made by the Dragonborn in the civil war storyline.
The mine itself contains four Corundum Ore deposits, and several pickaxes. Outside, if you swim upriver and to the left, you will find a silver vein.
A small family of miners live in the house next to the mine. Speaking with Annekke Crag-Jumper will start a miscellaneous quest entitled, "Kill the Leader of Gallows Rock".
Sondas Drenim, another resident of the mine, tells of the dangers of deep mines and asks you to Deliver Sondas's Note to Quintus, requesting medical supplies.