Look for a new crypt. AFAIK they are not respawning.

There are a lot more island with Black Forest, its very common so there will also be a lot more burial chambers :)

Keep searching friend. There are plenty more burial chambers in the world.

The yellow mushrooms will respawn, but nothing else.

In a pinch, you can tear down the kiln or smelter and only make one at a time. That is, build the kiln, make coal, tear it down, build smelter, smelt metal ... back and forth. That would free up some cores to use for portals as you continue your search.

They do not respawn in burial chambers. But there usually are more burial chambers to plunder in the black forest.

Best place for a respawning source of surtling cores is in the swamps. But there's no need to hurry there.

If you want a infinte supply build a portal from your base, get some materials a base etc.. then go south as far as you can until you get to ashlands. build a small base portal up and then you can farm them from the fire guys walking around. FYI THERES ALOT OF THEM

Keep looking for new burial chambers in the BF. They are everywhere. By the time you have cleared out 15 to 20 you will be ready for the swamp. Make a simple Surtling farm at one of the fire spawns in Swamp. Best if you can find two or three close together. You can farm lots of cores. Just put a portal on top of a close crypt and you are all set. Make a trail to farm leeches and draugr along the way. And if you're lucky you will find an abomination for a little excitement.

What do ya'll do with the cores anyhow, I dig out the flame fountains to get scores of coal on demand but I end up with a pile of cores, is there a grenade later on or somethin that uses them now or do I just chuck them all into bonfires for sparkles?