Received from: Notice board (M15, 2)
Step 1: Go to the mine and find out where the monsters are coming from
The mission is connected with a notice on the bulletin board " Proclamation of Closure of the Mines". After completing The War Council, you will find a few dwarves sitting by a table inside the tavern (M15, 1) (including Zoltan and Dandelion). Talk to them to learn that the mine is closed and it's high time someone did something about it. Go meet the dwarves in front of the mine (M15, 9)
Notice! Before you enter the mine, equip yourself with three beehives - you will need them to collapse the Rotfiends' tunnels.
Step 2: Collapse the breaches using beehives
Once you enter one of the tunnels, you will note a breach through which Rotfiends are probably coming out. Geralt will come up with an idea to cut off the entrances and stop the Rotfiends from spreading throughout the mine. There are three tunnels inside the mine, their locations have been marked on the map in the guide, under the same number (M16, 2). A detailed description of passing through the mine can be found in the description of Subterranean Life, as it's connected with the plot and you're probably going to complete it simultaneously with this one.
Step 3: Get your reward from Cecil Burdon
After collapsing the last tunnel, leave the tunnel and head to the elder, Cecil Burdon (M15, 12), to get your reward. You will receive the Formula: Hardened Leather Boots.