Hey everyone, get ready to learn about the Driller's Drills! It's MeatShield, back at it again, here to share everything I've researched and documented in the past couple days. In a shocking turn of events, I'm going to be publishing two blog posts on separate topics virtually back-to-back. For context, on the evening of August 9 I was contacted by the YouTube content creator "Drilling In The Name Of" who asked if I could provide him with a detailed breakdown of how the Drills' mining mechanic works. He was in the middle of working on a video that compared Drills' T1.A "Barbed Drills" vs T1.B "Hardened Drill Tips", but when he did a side-by-side comparison of the two he noticed that there didn't seem to be much of a difference in distance mined. This led him in search of answers, and the discoveries made during our conversation became such a rabbit hole that his project had to be split into two videos. Because the Drills were on my list of "things to research, figure out, and document", I figured this week would be a good opportunity to do that and help him out. Without further ado, let's dive into the Reinforced Power Drills!

How do they work "under the hood"?

Internal values

Basic

• 5.5 Max Heat
• 1 Heat/sec generated while using
• 2 Heat/sec Cooling Rate when not Overheated
• 8 second Overheat duration
• 38 liters of Fuel

Damage/Combat

• 8 Damage ticks per second
• 5 Melee damage per tick, with 10000% Armor Breaking (500 Armor Damage per tick)
• 0.2 liters of Fuel consumed per melee attack
• 50% Base Fear Chance per tick
• 25% chance per tick to Stun for 1 second

Mining

• 1.5 Mining ticks per second (called "Mining Rate" in the Equipment Terminal)
• 0.25 liters of Fuel consumed per dig
• x1.1 Movement speed while using
• 0.5 Movement penalty while using (don't worry, I explain how these two contradictory values work together in the next subsection)
• While mining horizontally, each dig will attempt to remove terrain in a [1.5m deep by 2m wide by 2.2m tall] chunk in front of the Driller

How do those values work together?

Heat Meter

Very similar to how the Minigun works, the Drills generate 1 Heat per second of continuous use, regardless of the amount of fuel spent. Because of the Max Heat of 5.5, that means you can use the Drills for 5.5 seconds before they Overheat. If the Drills Overheat, then you have to wait 8 seconds for them to "unjam" before you can use them again. On the other hand, if you stop using them before the Heat Meter on the righthand Drill says 100%, then it will immediately start cooling off at -2 Heat/sec. To phrase it a different way: if you use the Drills for 4 seconds, then it will only take 2 seconds to cool off by default.

Fuel Consumption Rate

The amount of Fuel consumed every time you use the Drills is dependent on what they're in contact with. If you're hitting terrain (or nothing at all), then the Drills will consume 0.25L every 2/3 of a second (because the Mining Rate starts at 1.5). In contrast, if the Drills are hitting anything with a healthbar (enemies, allies, lootbugs, even ebonuts) then it will consume 0.2L every 1/8 of a second. As a result, without upgrades, Drills will consume 0.375 L/sec when going through terrain or 1.6 L/sec when dealing damage to enemies. If you equip both of the Mining Speed upgrades, then digging through terrain will consume 0.75 L/sec but the enemies will still use fuel at 1.6 L/sec.

Movement Speed while Drilling

For reference, the default walking speed of the dwarves is 3 m/sec, or 4.5 m/sec when doing missions with the Rich Atmosphere anomaly. By using a console command, I was able to see that Driller walks at 1.98 m/sec with no mining speed upgrades, 2.31 m/sec with one mining speed upgrade, and 2.64 m/sec with both mining speed upgrades equipped. After some algebra and a little "guess and check", I found that the formula that matches those numbers is:

Walking Speed * MovementWhileUsing * (0.1 + MovementPenalty)

Total Distance Drilled Horizontally

Because the fuel consumption is set at 0.25L per dig, the total distance that Drills can tunnel is independent of Mining Speed. A quick approximation is [38L * 4 digs/L * 1 m/dig = 152m], with each +6L upgrade granting an additional 24m of distance. Getting the Mining Speed upgrades will help you tunnel that distance faster, but ultimately you won't get further.

What do the mods do?

Thankfully, most of the Drills' mods work intuitively. The only one that I want to explain in a little more detail is T4.B "Bloody Cold Drills". When I looked in the game files, I saw that it removes 0.2 Heat every time that the Drills damage an enemy. Combine that with the Damage RoF of 8, and it means that it sheds 1.6 Heat/sec while attacking enemies. As a result of that, the Heat removed by T4.B is actually greater than the amount of Heat generated by using, so you actually shed Heat while drilling into enemies. As long as your Drills are doing damage, you can theoretically spend your entire Max Fuel without ever Overheating.

What is the optimal build for Mining?

So, we finally come to the original question that Drilling In The Name Of asked me. When everything is put together, what is the optimal mod selection for mining?

TL;DR

If you just want to skip to the answer: equip T3.A but not  T1.B to optimize your fuel usage, or equip both T3.A and T1.B to optimize speed at the cost of occasionally wasting fuel.

Doing the math

To start answering this question, let's dive into some of the more nitty-gritty details I've observed during my tests in the past couple of days. There are three important numbers that I haven't listed yet because I haven't seen them referenced in any of the game files, but they are crucial to answering this question:

1. How far away can Drills break terrain?
2. How far do the Drills dig every time they break terrain?
3. How close can the Driller get to a wall?

After almost 6 hours of testing and math, here are the values that I've calculated/observed for each of those three numbers:

1. According to the Laser Pointer, Drills can break terrain that is less than 2m away horizontally
2. In order to account for a special case I'll detail later, I calculated that Drills dig 1.03m horizontally every time they successfully break terrain.
3. According to the Laser Pointer, you can stand 0.4m away, but the number I calculated was 0.47m (again, for the special case I'm about to talk about)

Now, using those numbers, here's a table comparing the movespeed of Driller and the m/sec of terrain cleared with various combinations of the Mining Speed upgrades:

Using that table, it becomes quite easy to see that the only case where the Drills clear out terrain faster than the Driller can move is when both upgrades are equipped. This is the "special case" that I mentioned, because the Drills are clearing terrain so much faster than Driller walks that it's actually possible to waste fuel. If you just hold W and Mouse1 until the Drills overheat with both Mining Speed upgrades, it will attempt to make 16 digs but only 15 of them will actually break terrain, causing 1/16 of your fuel to be wasted. You can actually calculate which chunk fails to break for yourself following these steps:

1. Let 'L' be the starting distance away from the wall (default to 0.47m), let 'M' be the Mining Rate, and let 'W' be movement speed while drilling. Solve for 'N' as the number of the dig that will fail.
2. We know that it can't break terrain that's 2m or further away, so just solve:

L + N*(1.03 - W/M) < 2
N*(1.03 - 2.64/3) < 2 - 0.47
N*(0.15) < 1.53
N < 1.53/0.15
N < 10.2

This shows that if you start by running into a wall (achieving L = 0.47m), then the 11th dig will fail and you'll walk forward another 0.88m which brings the total distance below 2m again. In this example, you wouldn't exceed 2m again before the Drills overheat so 15 out of 16 digs would succeed. The further away you are from the wall when you start breaking terrain, the sooner that it will "skip". In extreme cases, you could get up to 3 "skips" and waste even more fuel.

Drawing conclusions

So, with all of that math done, what is the optimal build for mining? Let's review what we've seen:

• If the drills don't overheat, it only takes 1/2 of time spent drilling to fully cool down, or 1/3 the time if you equip T2.A. That's strictly better than T2.B's -3 sec Overheat duration in every situation, so never let your Drills overheat to optimize digging.
• With no Mining Speed upgrades, Driller walks faster than the terrain gets cleared so it wastes time walking against the wall
• With one Mining Speed upgrade, Driller walks at virtually the same speed as terrain gets cleared
• With both Mining Speed upgrades, Driller walks slower than terrain gets cleared so it's possible to spend fuel on a dig that doesn't actually break terrain. However, it is significantly faster digging than just one upgrade even if fuel gets wasted.

As such, my answer is "are you optimizing fuel usage, or minimizing time spent?" If you're looking to make sure every last drop of your Fuel is spent on clearing terrain, then the optimal build would be to equip T3.A but not T1.B. On the other hand, if you want to get from A to B as fast as physically possible, then get both T3.A and T1.B and be conscious of the fuel "wasted" by just W+M1'ing.

There's a third option, however! This little paragraph goes out to all the people who read more than the TLDR ;-) If you want most the speed of both Mining upgrades with none of the fuel wasting, I strongly recommend doing "bursts" of drilling. Use your ears and count 4 of the terrain breaking sounds, release Mouse1 and let the Drills cool down a little bit while you walk your nose into the wall again. Resume drilling and repeat the pattern of "1, 2, 3, 4, cool while walking". You'll lose a little bit of raw speed using this method, but you'll ensure that you break terrain every time you consume fuel and it's still faster than just one Mining Speed upgrade.

Battle Drills

Beyond their extreme utility as a traversal tool, you can also whip out the Drills to damage enemies or apply some crowd control. On their own, they only do 40 DPS but thanks to their high Rate of Fire they'll quickly incite Fear on enemies, as well as stunning them. The (frankly ridiculous) Armor Breaking is great too; you're able to peel the armor off of every enemy in only a damage tick or two, even Elite Praetorians! So, they're a great "support tool" in a vacuum, but then we get to the upgrades and combos.

Upgrades

In the Drills' mod tree, there are only two upgrades that directly affect their combat abilities: T1.A "Barbed Drills" and T4.B "Bloody Cold Drills". Barbed Drills increases the damage per tick from 5 to 10, and subsequently increases the DPS from 40 to 80. As I've already mentioned in the "What do the mods do?" subsection, Bloody Cold Drills let you use your drills continuously without overheating as long as you're damaging an enemy. It's like Minigun's T5.B "Cold as the Grave" but better!

Combos

The real strength of Drills in combat lies in how they work in tandem with the Cryo Cannon and the passive perk Vampire. Not only do the Drills deal 3x damage to Frozen enemies, they also use Melee-element damage. This means that Freezing an enemy with the Cryo Cannon and then swapping to Drills with T1.A equipped will do 240 DPS, and when it gets a kill on a medium or larger enemy it will heal you for +5 HP via Vampire. This combination is so effective that it has become one of the dominant playstyles for Driller. Bring along the Impact Axes when you're doing this combo, because they can trigger Vampire's healing, too. There are plenty of builds and YouTube videos that go over this combo and give some demonstrations, so there's lots of material available if you want to learn more!

That's it for this blog post! Although it's a pretty thorough look at the Drills, it's still one of my shorter entries. Hopefully everyone can learn something from this, and Drillers everywhere can improve their Drills usage! Drilling In The Name Of is releasing the first video about Drills alongside this blog post, and the second part will be coming out in the near future so keep an eye on his channel uploads. If you have any questions or comments, feel free to reach out to me on the DRG Community Tools Discord.

Rock & Stone!
-MeatShield