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A heavy mechanoid built for mining in treacherous locations. While intended for excavation, the tunneler's gigantic power claws and ultra-thick armor makes it a dangerous force in combat.

Base Stats

Market Value
1200 Silver


Armor - Sharp
Armor - Blunt
Armor - Heat

Pawn Stats

Combat Power
Move Speed
1.9 c/s
Health Scale
Body Size
210 kg
Pack Capacity
122.5 kg
Carrying Capacity
263 kg
Filth Rate
Comfortable Temp Range
-100 °C – 250 °C (-148 °F – 482 °F)

Melee Combat

Attack 1
Left power claw
22 dmg (Scratch)
33 % AP
2.9 second cooldown
Attack 2
Right power claw
22 dmg (Scratch)
33 % AP
2.9 second cooldown
Average DPS


Crafted At
Large mech gestator
Required Research
Standard mechtech
Gestation Cycles
Resources to make
Steel 150 + Plasteel 75 + Component 4 + Standard subcore 1

A tunneler is a mechanoid added by the Biotech DLC.


Tunnelers can be gestated by a mechanitor at a Large mech gestator once the Standard mechtech research project has been completed. They require Steel 150 Steel, Plasteel 75 Plasteel, Component 4 Components, Standard subcore 1 Standard subcore and 4 gestation cycles taking 1,800 ticks (30 secs) each to initiate. They take up 3 bandwidth from their linked mechanitor.

Dead, friendly tunnelers can also be resurrected at the large mech gestator using the "Resurrect heavy mechanoid" bill. This requires the corpse of the friendly tunneler, Steel 100 steel, and 1 gestation cycle taking 1,800 ticks (30 secs) to initiate.


As mechanoids, every tunneler is immune to fire, Flame and Heat damage, and temperature extremes, despite having Comfortable Temperatures defined. They have 100% Toxic Resistance and Toxic Environment Resistance, making them immune to toxic buildup, rot stink and other toxic effects. They do not need to eat, rest, and have no mood. They will be stunned by EMP attacks for a time proportional to the EMP damage inflicted and will "adapt" and rendered immune to further EMP strikes for 2,200 ticks (36.67 secs).

Dead tunnelers may be shredded at the machining table or crafting spot for Steel 20 steel and Plasteel 10 plasteel. However, these values are affected by mechanoid shredding efficiency, as well as missing parts on the tunneler.

Tunnelers do not seem to spawn in regular mech raids, crashed ship parts, or mech clustersContent added by the Royalty DLC.[Verify] However, they appear as part of certain war queen and apocriton summon groups.


In combat, tunnelers use sharp melee attacks. They have an innate smokepop pack ability, but this has a cooldown of 15 days.

Tunnelers have the highest armor values of any mechanoid in the game, with +5% more Sharp and Blunt armor than the war queen. However, with a health scale of 1.52, it doesn't have the hit point pool of the larger mechs. They have an innate shield, which is equivalent to a shield belt, just with 250 HP. This is higher than even a legendary quality shield belt.

Tunnelers use regular staggering mechanics, as with any other enemy. A tunneler can theoretically be staggered by a weapon with at least 3.5 stopping power, however no weapon in the game has enough stopping power to do so.



As an ally[edit]

Once made, they recharge in a large mech recharger (50% power/day), creating 15 wastepacks whenever the recharger's waste is filled up.


Tunnelers will do tasks associated with the Mining tab, though are unable to use deep drills. They cannot be manually controlled, except when drafted for combat. They have an effective Mining skill of 10, but with a Global Work Speed of 150%.

For reference, every other labor mechanoid has a Global Work Speed of 50%. As control sublinks and the Mechanoid Labor preceptContent added by the Ideology DLC both act as additive offsets to work speed, the tunneler receives a relatively smaller boost. For example, a cleansweeper could go from 50% to 70% work speed - a ×140% increase. A tunneler would go from 150% to 170%, which is only a ×113.3% increase.


Tunnelers are useful for mass mining operations, whether it is expanding out your mountain base or mining mineral lumps found using a long-range mineral scanner. Mechanoids are not subject to illness or mental breaks, and only recharge for 2 days out of every 12.

Work Speed[edit]

The following table summarizes the work speed effects of operating within the influence of a mech booster and having control sublinks installed by the Mechanitor. All values are for 50%+ lighting conditions.

Control Sublinks Work Speed Mech Boosted
0 150% 225%
1 156% 231%
2 162% 237%
3 168% 243%
4 174% 249%
5 180% 255%
6 186% 261%

A colonist's work speed is based on their Mining Speed stat. At about skill 13, a normal colonist with no traits or health conditions will mine as fast as a tunneler operating without a Mech Booster or Sublink bonus. A similar colonist at skill 18 mines roughly 97% as fast a mech-boosted Tunneler with no Sublink bonuses. Installing a Drill arm allows a Skill 5 pawn to mine faster than an unboosted Tunneler.[Mining Specialist?]

Mining Yield[edit]

Tunnelers appear to have no special modifiers to Mining Yield, meaning that they function identically to a Skill 10 Colonist for this purpose. Higher skilled colonists will extract more material, but the increase isn't very large until very high skill levels. For comparison, a healthy, level 20 human miner has the maximum possible mining yield of 113% compared to the 102% of the tunneler. For maximum resources, leave ores for higher skill colonists, if present, to mine. However, it may be more useful to get a place dug out now then to get a little more ore.

Conversely, a lower mining yield will slightly lower the amount of stone chunks that have to be hauled out of a mountain base. The difference is too small to notice, either way.

As an ally in combat[edit]

Tunnelers are incredibly slow, with middling DPS and a decent durability. They have 152% the health of a human, armor slightly worse than normal recon armor, and an innate shield better than a legendary shield belt. While they won't deal as much damage compared to a dedicated melee pawn, nor able to run or lock down enemies like a scyther, tunnelers can draw enemy fire. This lets other combatants focus on dealing damage.

Comparison to scythers[edit]

Tunnelers face competition from scythers, a melee-focused mech also unlocked from Standard mechtech. Tunnelers don't have a scyther's speed, and consume +1 bandwidth. However, they are significantly more durable, with significantly more armor, slightly higher health, and the aforementioned shield. Tunnelers cost Steel 75 steel more to make.

This is at the cost of DPS. The tunneler has a true DPS of 7.59 (4.7 after Melee Hit Chance), 75.9% of the scyther. The slightly higher AP of the tunneler does not matter in practice. Both tunnelers and scythers deal sharp damage

If durability is completely irrelevant, such as when using Skip psycast Content added by the Royalty DLC mobbing tactics, then scythers are superior due to their lower bandwidth cost. If durability is relevant, such as for melee block tactics, then you may want a tunneler. In addition, a tunneler used for mining might as well be used for combat whenever possible.

Comparison to centipedes[edit]

As durable mechs, tunnelers also face competition from centipedes. Centipedes have 288% the health scale and thus HP of the tunneler. In return, it has slightly worse armor (Sharp: 72% Blunt: 22%) and no shield belt. In addition, centipedes cost 1 more bandwidth and are unlocked at High mechtech. All centipedes have identical durability to each other.

Centipedes deal 86% of the base true melee DPS, however their melee attack deals Blunt damage. Against enemies with high sharp armor, centipedes can actually do more damage. For example, a centipede headbutt has enough AP to ignore another centipede's armor, but the tunneler would have its damage reduced by 70%. After considering the mechanics of the Scratch damage type, the tunneler is slightly better against unarmored targets and slightly worse against armored.

So for the sole purpose of tanking enemies, the centipede is almost always better even when considering the tunneler's shield. The centipede's ranged weaponry makes them more flexible in combat. But centipedes are more expensive. When a centipede is tied up in melee, unable to fire while being fired at, it won't be much better than a tunneler.


Body parts[edit]

Body Part Name Health Quantity Coverage[1] Target Chance[2] Subpart of Internal Capacity[3] Effect if Destroyed/Removed
Thorax 60 1 100% 2% N/A[4] Ex.png - Death
Will never take permanent injury
Neck 45 1 10% 2% Thorax Ex.png Communication Death
Will never take permanent injury
Head 45 1 80% 2.7% Neck Ex.png - Death
Will never take permanent injury
Artificial Brain 15 1 10% 0.8% Head Check.png Data Processing Death
Will never take permanent injury
Sight Sensor 15 2 13% 1% Head Ex.png Sight −25% Sight. −100% if both lost.
Will never take permanent injury
Hearing Sensor 15 2 10% 0.8% Head Ex.png Hearing −25% Hearing. −100% if both lost.
Will never take permanent injury
Chemical Analyzer 15 1 10% 0.8% Head Ex.png - Will never take permanent injury
Shoulder 37.5 2 17% 2.5% Thorax Ex.png Manipulation −50% Manipulation.
Will never take permanent injury
Arm 45 2 85% 12% Shoulder Ex.png Manipulation −50% Manipulation.
Will never take permanent injury
Power Claw 60 2 20% 2.9% Arm Ex.png - Will never take permanent injury
Leg 45 2 20% 16% Thorax Ex.png Moving −50% Moving.
Will never take permanent injury
Foot 30 2 20% 4% Leg Ex.png Moving −50% Moving.
Will never take permanent injury
Reactor 30 1 6% 6% Thorax Check.png Power Generation Death
Will never take permanent injury
Fluid Reprocessor 22.5 2 4% 4% Thorax Check.png Fluid Reprocessing Death if both lost
−50% Fluid reprocessing
Will never take permanent injury
  1. Coverage determines the chance to hit this body part. It refers to the percentage of the super-part that this part covers, before its own sub-parts claim their own percentage. For example, if the base coverage of the super-part is 100%, and the coverage of the part is 20%, 20% of hits would hit the part, and 80% the super-part. If the part had its own sub-part with 50% coverage, the chances would be 10% sub-part, 10% part, 80% super part.
  2. Target Chance is the actual chance for each part to be be selected as the target when each part's coverage has been taken into account(I.E. Neck covers 7.5% of Torso but Head covers 80% of Neck so it actually has only a 1.5% chance to be selected). This is not pure hit chance, as different damage types propagate damage in different ways. See that page for details.
  3. Note that capacities can affect other capacities in turn. Only the primary effect is listed. See specific pages for details.
  4. This is the part that everything else connects to to be considered 'connected'.


Version history[edit]

  • Biotech DLC Release - Added
  • Somewhere between Release and 1.4.3641 - Power claw attack changed from Blunt to Scratch.
  • 1.4.3531 - Increased armor values from 40/20/200 to 80/40/200
  • 1.4.3682 - Removed special stagger mechanic from tunneler mechs. Previously, tunnelers would be staggered for 120 ticks (2 secs) on any ranged attack, no matter how strong it was. Staggering is now based on weapon stopping power as with all other pawns.