After the dialog with Knocky, who tells you where to get the ore, you go to the mine and talk with the soldiers. The officer will give you a quest to get an access permit. After finishing that quest to get the permit, you can access the mine and find the katryx ore inside.
Aldin, city map, Mirel in party, blacsmith, elf. Next go to field in left site of Aldin city and to bottom, he will stand here, talk again, he will take you to hidden willage, in that willage, blacksmith (black haired elf girl in leather brown dress), talk when katryx ore quest active, next go to mine and talk to green suit soldier, go to whitestone citadel (if I don't mess the spelling) talk with capitan in sleeping chamber (green haired with glasses) go back to soldier and enter mine, it is green ore on other site of poison lake. i hope it will help