Windshear Mine is located within Windshear Crag and is filled with aggressive kobold miners who are working for the Venture Company. It is a good source of [Tin Ore].
Piznik can be found deep in the mine, working undercover for Ziz Fizziks. He starts the short quest line  Gerenzo's Orders.
This section concerns content exclusive to Cataclysm.
The mine appears to be have been taken over by the Horde.