The quest of the abandoned mine hasn't been implemented now, but you can try to defeat the haunted gnolls if you are strong enough.
To me, the strategy for defeating them is to attract one haunted gnoll, not 2 or more, to fight against, and then the stronger you are, the more haunted gnolls you can attract to defeat. The most I can fight against is 3 now.

How lucky NoName, for me even if I've almost filled the 26 ability slot, as a Mage, I cannot fight ever one of them.... maybe I've poor equip? ..... sigh

@lthiliath,
Yah, equipments are important, and how to equip to fit your class and skill tree is challenging. I deleted my Mage character cos I hadn't found good equipments, and my skill tree made me hard to find good equips either. Both equips and skills are interactive.