When the party made it to the abandoned mine they discovered there the remains of a great number of orcs and goblins, and met a ranger from many sessions back who had previously tried to get the party to join him. He and a merchant from town (a high level thief) had been slowly whittling down the numbers of the creatures here, but the thief had finally had enough and left. All of the goblins were afflicted with the strange illness that makes them even more stupid than usual.
They made camp and kept watch on the four entrances. Gladric and Vadco were able to capture a figure which emerged and had tried to sneak up on them. After a lot of questioning and threats, this cloaked human explained how he was a servant of an evil wizard who himself was employed by the leader of the bandits. He was the only one of the slaves kept that wasn’t diseased - and he’d been attempting to pour a poison into the ears of party members as they slept. The poison he carried was a small jar which actually contained a piece of a larger jelly-like creature of some kind. This man said it was intelligent and working with the wizard.
Gladric gained some more information from him about the layout of the chambers closest to the four entrances to the mine. Later, Gladric and several others entered one of the entrances and descended several hundred steps to verify the story they were told - that there was a sealed portal on the ground at the bottom of the stairs. Ouze the cleric identified a glyph of protection from evil on the portal and they were reluctant to open it in case it was keeping something trapped inside. They rejoined the others on the surface.
Then a plan was hatched to cover two of the other small openings to the mine with skins and blankets and build a fire inside the entrance to the one their captive had crept out of… This took a while to make happen but eventually there was a lot of smoke being produced. The idea was that it would be better to try to get the diseased orcs and goblins their captive had described to come out and fight in the open rather than risk ambush or traps. Nothing came out, but they pitched camp another night thinking that even if it hadn’t been enough to drive them out, they might now come to investigate the cause of the fire. Whether they were right or by chance, seven did come out - all were killed with no party losses, though there were a couple of close calls.