Updated November 6, 2026. Applies to Valheim 1.0, patch 1.0.21. Room, loot and enemy numbers come from the community Valheim Wiki. We also checked Iron Gate's patch notes on Steam, up to patch 1.0.21. No 1.0 patch has changed how Infested Mines work.
Infested Mines are the Mistlands dungeon. They are the only reliable source of the two items that move you through the biome: Black Cores for your Mistlands crafting stations and Sealbreaker Fragments for the key to The Queen. They are also the place most players get stuck. The Seekers dive at you from across the room, hidden doors look like plain walls, and some mines hold almost nothing.
This guide covers where Infested Mines spawn and how to spot an entrance. It explains both hidden door types and what each mine can drop. It covers what respawns and what doesn't, and the gear and tactics that make a clear-out safe.
Quick answer: Infested Mines appear only in the Mistlands, under Black Marble buildings or inside large rock formations. Look for two blue torches flanking a long, straight staircase. Inside, you need 15 Black Cores (5 each for the Black Forge, Galdr Table and Eitr Refinery) and 9 Sealbreaker Fragments for the Sealbreaker. Cores sit on stands, mostly in treasure rooms behind hidden doors with blue runes. Fragments sit in glass cases you smash. A mine can have anywhere from 0 to more than 10 cores. Only Royal Jelly piles and some enemies respawn, on a 4-hour timer.
Where do you find Infested Mines in Valheim?
Infested Mines are a Mistlands-only dungeon. The wiki lists two entrance types:
- Under Black Marble buildings. These are the big Dvergr ruins you see through the mist. The entrance sits beneath the structure.
- Inside large stone formations. You see a long, straight staircase cut into the rock, with two blue torches on either side.
Both entrances are usually guarded by several Seekers. Expect a fight on the doorstep before you go down.
The Mistlands start far from the world centre. The biome runs from about 5,900 m to 10,000 m out, so you need a boat and a long trip. If you have never seen the biome, start with our Mistlands survival guide. It covers the mist, the Gjall and getting set up.
Why can't I find any Infested Mines? Most of the time it is the mist, not missing mines. Craft a Wisplight (1 Silver plus 1 Wisp at the Workbench) before you search. In 1.0 it clears the mist in a 15 m radius, up from 10 m before 1.0. It takes the same slot as Megingjord and the Wishbone, so you can't wear them together. Search near large Black Marble ruins first.
What is inside an Infested Mine?
Each mine is a set of rooms that usually branch off one main rectangular hall. The wiki puts the size at 16 to 96 rooms per mine. That range is why two mines can feel nothing alike.
Here is everything the mine can give you:
| Resource | Where it is | Used for |
|---|---|---|
| Black Core | On stands, mostly in treasure rooms behind hidden doors | Black Forge, Galdr Table, Eitr Refinery (5 each), Shield Core (1) |
| Sealbreaker Fragment | Inside glass cases lit blue, all over the mine | 9 make one Sealbreaker at the Galdr Table |
| Royal Jelly | Piles on the floor; also dropped by Seeker Broods | Major Healing mead base, Seeker Aspic, Yggdrasil Porridge |
| Infested Mine Chest | Treasure rooms | Coins, minor meads, Sausages, Dvergr Tankard, Hook |
| Coins | Piles in treasure rooms | About 138.5 coins per pile on average |
| Surtling Core + Copper Scrap | Destroyed Dvergr lanterns | Smelters, kilns, etc. |
| Wood / Black Marble | Broken barricades / broken railings | Building |
Royal Jelly is also a decent snack while you clear. Each piece gives 15 Health and 15 Stamina for 15 minutes (900 s), so it works as a cheap third food slot inside the mine.
How do hidden doors work in Infested Mines?
Hidden doors are the reason players leave mines with "only two cores". There are two kinds, and they lead to different places.
| Door type | How to spot it | Where it leads |
|---|---|---|
| Hidden door | A small marble block with glowing blue runes on it | Treasure rooms: Black Cores on stands, coin piles, a chest, and no enemies |
| Old Dvergr gate | Looks almost like a solid marble wall, except for a carved Dvergr face | Usually ordinary passages or rooms |
Both open the same way: walk up and interact with them. You don't need a key or a tool. Once open, they can't be closed again. That is useful later, because an open doorway shows which rooms you already searched.
The third kind of block is the wooden barricade. You have to break it with a weapon to pass. Barricades are not hidden, but they are easy to skip in the dark when a fight pulls you somewhere else.
How to search a mine properly:
- Clear the main hall first, then work outward one branch at a time.
- In each room, sweep the walls slowly. Look for blue runes and the Dvergr face. Both are easy to miss in green light.
- Break every barricade you see. Some only lead to a dead-end room, but you can't know which without breaking them.
- Watch for drops in the floor and gaps at head height. The wiki compares the layout to Frost Caves: rooms open up and down, not just sideways.
- Before you leave, walk the main hall once more and check for doorways you haven't opened.
How many Black Cores are in an Infested Mine?
There is no fixed number. The wiki puts it at 0 or more per mine, usually at least two. It also says mines with zero cores are "not uncommon" and some mines have over 10. The count depends on which rooms the mine rolled and how many rooms it has.
That randomness is the most common complaint about the mines right now. A post on r/valheim on November 5, 2026 put it like this: "Two black cores for all. Looked in every nook and cranny for anything else." The group had run four mines. It isn't bad luck in one mine, it's how the dungeon is built. Plan on clearing several mines before you have all 15 cores.
Here is what each core is for:
| Station | Black Cores | Other materials |
|---|---|---|
| Black Forge | 5 | 10 Black Marble, 10 Yggdrasil Wood |
| Galdr Table | 5 | 10 Black Metal, 20 Yggdrasil Wood, 5 Refined Eitr |
| Eitr Refinery | 5 | 20 Black Marble, 5 Black Metal, 10 Yggdrasil Wood, 3 Sap |
| Shield Core (for the Shield Generator) | 1 each | 1 Surtling Core, 5 Ceramic Plate, Artisan Table level 2 |
Build order tip: the Galdr Table needs Refined Eitr, and Refined Eitr comes from the Eitr Refinery. So put your first 5 cores into the Black Forge, the next 5 into the Eitr Refinery, and the last 5 into the Galdr Table. Our crafting station upgrades guide lists every Black Forge and Galdr Table upgrade after that.
Black Cores can go through portals. You don't need to sail them home.
Deep North bonus: in 1.0, the wiki also lists Black Cores inside Ancient Chests in Mörkhalla in the Deep North. That doesn't help a first Mistlands run, but it means late-game players have a second source for extra Shield Cores.
How do you get Sealbreaker Fragments and summon The Queen?
Sealbreaker Fragments sit inside glass cases lit in blue all over the mine. Smash the case and pick up the fragment. You need 9 fragments. Combine them into one Sealbreaker at the Galdr Table (level 1).
Three details matter:
- The Sealbreaker is not used up. It opens the seal to The Queen's arena and stays in your inventory.
- Fragments ignore the resource-rate world modifier, unlike other boss items. A "more resources" world gives you no extra.
- Trophies are for a rematch, not the door. The Queen is already alive inside the Infested Citadel, so the first fight needs only the Sealbreaker to open the Dvergr vault. After she dies, the Hive seat inside takes 3 Seeker Soldier trophies to summon her again. Soldiers have a chance to spawn in the larger mine rooms.
For the full boss order and what The Queen's power does, see our Valheim boss order guide.
Do Infested Mines respawn?
Partly. This is the part players most often get wrong.
| What | Respawns? |
|---|---|
| Royal Jelly piles | Yes, every 4 hours (since patch 0.213.4). A dripping jelly stalactite on the ceiling marks where each pile comes back. |
| Some enemies | Yes, every 4 hours. Seekers and some Tick spawn points refill. |
| Black Cores, Sealbreaker Fragments, chests, coin piles | Neither the wiki nor Iron Gate's patch notes say they respawn. Treat them as one-time loot. |
| Hidden doors and gates | Stay open forever once opened. |
So a cleared mine is worth a return trip only for Royal Jelly. For more cores, find a new mine.
Pro tip: the wiki confirms you can place a Campfire and a Cooking Station inside the mine. Bring one with you on a long clear-out to cook and rest without walking back up.
What enemies are in Infested Mines?
The wiki lists four enemy types. All except Seeker Broods can have stars. These are the base (0-star) numbers, with 1-star and 2-star in brackets:
| Enemy | Health | Biggest hit | What to know |
|---|---|---|---|
| Seeker | 200 (400 / 600) | Claw: 120 Pierce (180 / 240) | Flies and dive-bombs from range. Resists Blunt, Pierce and Slash. |
| Seeker Soldier | 1,500 (3,000 / 4,500) | Ground slam: 120 Blunt (180 / 240) | Spawns in larger rooms. Hit its abdomen: it takes 1.5x Blunt, Pierce, Slash, Fire, Frost and Lightning damage. |
| Tick | 50 (100 / 150) | Attach: 50 Pierce every 0.5 s for 5 s | Weak to Pierce. Parry it to knock it off. |
| Seeker Brood | 20 | Bite: 60 Pierce | Hatches from Seeker eggs and drops Royal Jelly. |
Two notes from the patch notes and the wiki:
- Broods give less adrenaline than they used to. The Call to Arms patch notes say: "Killing Seeker Broods now grants less adrenaline than before." Don't farm them to charge your trinket.
- Seekers ignore Spirit damage completely. Leave the silver and spirit gear at home.
The full Mistlands roster, including the Gjall outside, is in our Mistlands guide.
What is the best gear and strategy for Infested Mines?
The mines hit hard and fast, and almost all of it is physical. Build for that.
Forsaken power: Bonemass. The wiki's top pick for the mines. Seekers and their kin have no elemental attacks, and their dive-bomb does big physical damage. Bonemass's physical resistance makes those hits survivable. Our Forsaken power tier list ranks it against the others.
Chest piece: Root Harnesk. Gjall can't reach you underground and most mine damage is Pierce. That is why the wiki calls the Root Harnesk "a much better choice than any other breastplate" for the mines. Swap it in for the trip.
Food: keep one big Health food. Mage builds in Eitr-weave have very little armour. The wiki advises at least one good Health food so you can survive more than one heavy hit. Our food tier list has the best options per biome.
Weapons that hit through walls. Sledgehammers and battleaxes hit through walls, so you can kill Seekers from behind cover. Ooze Bombs do the same at range.
Tactics that keep you alive:
- Don't break walls or barricades until the section in front of you is clear. Every opened wall can pull another room on you.
- Fight at doorways. Seekers need room to dive. A corridor takes that away.
- Keep a clear path to the exit. If a 2-star Soldier walks in, you want to back off, not get cornered.
- Watch the drops. Rooms stack vertically. Falling into an uncleared room below is a common death.
FAQ
Where are Infested Mines in Valheim? Only in the Mistlands. They sit under Black Marble Dvergr buildings or inside large rock formations, with two blue torches on either side of a long straight staircase. Seekers usually guard the entrance.
How do you open hidden doors in Infested Mines? Walk up to them and interact. Hidden doors are small marble blocks with glowing blue runes and lead to treasure rooms with Black Cores. Old Dvergr gates look like a wall with a carved face and lead to normal rooms. Neither can be closed again.
Why did my Infested Mine have no Black Cores? The number is random. Mines have between 16 and 96 rooms, and cores mostly appear in treasure rooms. Some mines roll none, others have more than 10. Check every hidden door first, then try another mine.
Do Infested Mines respawn in Valheim 1.0? Only partly. Royal Jelly piles and some enemies come back every 4 hours. Neither the wiki nor the patch notes list Black Cores, Sealbreaker Fragments or chests as respawning, so treat a cleared mine as done for cores.
How many Black Cores do you need? 15 for one Black Forge, one Galdr Table and one Eitr Refinery (5 each). Each Shield Core for a Shield Generator needs one more.
Can you build a campfire inside an Infested Mine? Yes. The wiki confirms Campfires and Cooking Stations can be placed inside, so you can cook and rest during a long clear-out without leaving.
More Valheim guides
Heading into the Mistlands next? These guides cover what comes before and after the mines.
