You can find this Side Story in the northern section of Quarrycrest, with a miner at the top of town giving it out. It seems he is having some trouble digging through some rock with this pickaxe. To complete this quest, you will need either Therion or Tressa, and travel to Goldshore on the opposite side of the map. Once you get there, venture to the northern part of town and look for the Stonemonger in front of the equipment shop. Either Steal or Purchase the Orewell Whetstone from the Stonemonger, then bring it back to the miner in Quarrycrest to finish.