CRK Into the Depths Guide — Mines, Agar Cubes and Fossils

The Mine Workshop makes Into the Depths look like a Topping Tart building. The better reason to open it every day is the Mine Battle tab. An Epic-tier Mine Battle pays one Agar Cube, and per the wiki's table that cube melts into a Beast or Ancient Soulstone (or an Ancient Soulprism) after 12 hours — a high-rarity Soulstone source that never touches a banner. The Appraiser is the other sleeper: run the wiki's numbers on a Purple Fossil and it is a 15% shot at a Legendary Beascuit.

Into the Depths arrived in v6.3, The Flame Awakens, on April 9, 2025. Devsisters' August 26, 2026 update then reworked a good chunk of it: Recovery Tools, five new Venture Tools, an Ore Vein Shop, a full-HP rule for Ventures and an instant Time Jumper clear for all available Mine Battles. Neither the Fandom wiki nor cookierun.wiki has caught up with all of that, so where a number below comes from a wiki table, the sentence says which one, and where the official notice moved a number, the notice wins.

Topping Tart crafting and the Mine Shop's Tart prices already have their own page — our Topping Tarts guide — so this guide covers the Mines' other systems.

Opening the Mines

Into the Depths unlocks at Cookie Castle Lv.6. Clear the short questline, then build the facility for 3 Aurora Pillars, 3 Aurora Bricks and 3 Aurora Compasses; the quest pays 30,000 Kingdom EXP, 20,000 Coins and an XS Raspberry Topping Tart. Both wikis agree on the requirement.

The Mines are a separate area from the Kingdom, with their own rules:

• Up to 60 Cookies can be assigned to roam the Mines from the dashboard.
• Each Cookie has a 250 HP bar that exists only in the Mines, separate from battle HP.
• Tasks are worked by groups of up to four Cookies, who spend HP as they work and earn rewards as progress builds.
• Only a fully completed task pays its bonus reward, and finishing one costs the Cookies their entire HP bar.
• Idle Cookies recover HP in Breaktime, where four Quick Rest Seats recover HP twice as fast.

Here is what there is to do down there:

Mine Ventures: where the cards come from

A Venture sends Cookies down from Fl.1 (Fl.25 with the August 26 Radiant Golden Pickaxe, below), clearing as many floors as they can until every Cookie is out of HP or the venture timer runs out. The floor cap is Fl.200. Each floor pays an extra reward once it is 100% cleared, and deeper floors pay more. cookierun.wiki's floor table — which its own editors flag as needing an update — starts adding Crystals and Sugar Ore at Fl.10, Radiant Beascuit Dough at Fl.13 and a Random Mine Card at Fl.17.

Two rules changed on August 26: only Cookies at full HP can join a Venture, and a Venture now costs them less HP than before (the notice gives no figure). The first one is the one you feel. A Cookie at 240 of 250 HP can no longer tag along, so Breaktime and those four Quick Rest Seats now decide how often you can send a crew.

Both wikis list four kinds of Mine Card dropping from Ventures; the August 26 notice's Sizzling Frying Pan (below) adds Recovery Tool Cards to the mix:

• Ore Vein Cards, which other Cookies then mine.
• Venture Tool Cards, added to the Miner Pack for future Ventures.
• Cart Upgrade Cards, which permanently upgrade the Mine Cart.
• Mine Battle Cards, which you clear in Mine Battle.

Both wikis still call Ventures the only source of Mine Cards. That stopped being true on August 26: breaking down an Ore Vein Card now yields Radiant Ore Vein Crystals, which buy Mine Cards in the Ore Vein Shop (the notice also calls it the Mine Exchange), with purchase limits that reset weekly.

The Mine Cart

The cart carries six permanent Venture upgrades, each with 15 levels. Values are from the Fandom wiki's Mine Cart table:

The wiki's requirement row climbs from 3 items for Lv.2 to 50 for Lv.15; it labels them only "required items", and Cart Upgrade Cards are the Venture drop it describes as upgrading the cart. The Lantern's flavour text reads "Venture without losing HP under the light of this lantern", but its effect line says only that the HP price is frozen until the listed floor (Fl.40 at Lv.15), and neither wiki spells out whether that means free floors or a price that stops climbing. With the full-HP entry rule in place, HP is what limits how often a crew can go down, which makes Sturdy Tub and Guiding Lantern the two upgrades working on that limit directly.

Venture Tools and Recovery Tools

Venture Tools go in the Miner Pack. The August 26 update added five and split healing off into its own Recovery Tool category:

Source caution: both wikis still list the two snacks as Venture Tools at the old +10 and +25 HP (as "Light Snack" and "Hearty Lunch"). The notice converted them into Recovery Tools that heal a single Cookie during a Venture and raised the values to 50 and 100. Use the notice's numbers.

If you are holding a Razor-Sharp Greatsword, that is the tool to load: it turns a Venture into an extra Mine Battle Card, and both wikis name Mine Battles as the one place Agar Cubes come from.

Ore Vein Mining and Cookie Traits

An Ore Vein Card is mined by up to four Cookies at a time. They drain HP while they work and earn rewards for the card's set duration; working the whole duration pays the card's completion reward on top. Speed-ups shorten the duration.

Who gets in depends on the card's rarity. A Common vein only takes Cookies of a specific type (Charge, Magic and so on). Rare and Epic veins only take Cookies with a specific Trait, and some Epic veins add a bonus for a particular type on top. Traits exist only in the Mines, and most Cookies have two.

The Traits page names six vein families: Crispy Beascuit, Shiny Candy, Curious Fossil, Sweet Power Gem, Salty Tart and Sleek Agar. A few payouts are documented outright: Sweet Power Gem veins are one of Choco Chalk's two main sources, per cookierun.wiki's Currencies page; the August 26 update added an Epic Salty Tart Vein offering Sugar Ore; and the same update's new Tart Ore Vein pays 140 Sugar Ore on completion, plus Coins, EXP Star Jellies and 1-minute Speed-ups while it is worked.

All 23 Traits and what they unlock

Each Trait gives a bonus — to Ventures, to mining in general, or to one vein family — and every Trait except Venturous is also the entry requirement for one kind of Rare or Epic vein, which the wiki lists by the vein's condition. A "Falling rocks" vein needs Agile Cookies; a "Bitter cold" vein needs Cold-proof ones. The full list, from the Fandom wiki's Cookie Traits page:

Then there is No Trait, which the wiki says ignores Ore Vein requirements altogether. The wiki's No Trait category lists exactly one Cookie: Agar Agar Cookie, the Epic who launched in the same v6.3 update as the Mines. On a Rare or Epic vein whose Trait you are missing, she is the key that fits every lock.

Three Traits carry a penalty, and the penalty tells you where to send them. Venturous (+15% Venture Skill, -5% Mining Efficiency) is an explorer. Tenacious (+15% Mining Efficiency, -5% Venture Skill) is a miner. Intuitive cuts Ore Vein HP cost by 15% and raises Venture HP cost by 5%, so it is a miner too. Brawny (+10% Venture Skill) and Musical (+10% Mining Efficiency) are the penalty-free versions of the same split.

Which Cookies to send to which vein

The Fandom wiki's "Best Traits" table names the Traits and Cookies it recommends for each job. The Cookies are the wiki's picks. Where a Cookie carries two of the job's Traits, per the wiki's Trait categories, the pair is in brackets:

The bracketed Cookies stack both of their job's bonuses — on a vein, that is the efficiency bonus and the HP-price cut together. The wiki's Trait categories list no Cookie holding both Traits of the Crispy Beascuit, Sweet Power Gem or Salty Tart veins, so on those three you are mixing Cookies, not hunting one perfect miner.

Break down the cards you can't staff. A Rare or Epic vein whose Trait you don't own is dead weight in your hand. Since August 26 it converts into Radiant Ore Vein Crystals, which spend in the Ore Vein Shop on cards you can actually work.

Mine Battles: the Soulstone tap

Mine Battle Cards come in two kinds: Cookie Battles, fought with a normal five-Cookie team, and MyCookie Battles, where you guide MyCookie. Both wikis give the same payouts:

Cookie Battles pay Radiant Beascuit Dough and MyCookie Battles pay Glowing Power Gems. The rules that shape how you play them, per cookierun.wiki:

• Battle Cards expire after 3 days. An unplayed card is a lost Agar Cube.
• Failing doesn't lose the card. Attempt every one, then try again with a different team.
• Cleared battles can be completed instantly with Time Jumpers, and the August 26 update added an option to instantly complete all available Mine Battles at once. Our Today's Bounties guide covers where Time Jumpers come from.

Radiant Beascuit Dough is the scarce reroll item — it resets one chosen Beascuit bonus effect, at 25 per reset on a Legendary per the wiki's Beascuits page (our Beascuit Dough costs guide covers rerolling) — so an Epic Cookie Battle's 4 is a real payout even before the cube.

Agar Cubes: three melting at once

An Agar Cube is "a slimy agar cube with a precious Cookie's Soulstone inside", and melting it takes time. The cube's rarity follows the battle's tier, per the Fandom wiki's table:

cookierun.wiki lists Witch alongside Ancient and Beast in its 12-hour melt-time note (it dates Witch's addition to the cubes to v7.2; the Witch rarity itself arrived in v7.0, per both wikis), and adds that once a Cookie's Soulstones are complete, Mine Battles pay its Soulcores instead. Battle Cards can name the Cookie inside the cube: the August 26 notice added one offering "Agar Cube: Ananas Dragon Cookie's Soulstone" — useful if you are building the Cookie in our Ananas Dragon guide.

Melting is the bottleneck. Only three cubes melt at a time. Three slots on a 12-hour melt is at most six Epic-tier cubes a day before any Sloth Yeast Ore, and only if you refill a slot the moment it opens. An empty slot is melt time you don't get back, so refill before you queue anything else.

The last column comes from Sloth Yeast Ore. Each piece speeds Agar Cube melting by 0.5%, up to 30% at 60 pieces, and it drops from Balloon Expeditions to Beast-Yeast Episodes 9 and 10, per the wiki's Yeast Ore page. If you already run the Dock, our Balloon Expedition guide covers crewing it.

Source caution: both wikis' intro paragraphs list Agar Cubes among Ore Vein rewards, but their own Agar Cube sections say they come only from Mine Battles. The battle table is the specific one; trust it.

The Appraiser: what a Fossil is worth

Fossils turn up in Ore Veins, and the Appraiser opens them. Both wikis carry the same three probability tables. One reading note first: each item in a row is its own outcome at the listed chance, not a bundle. Read that way, the Amber and Emerald tables each add up to exactly 100%; read as bundles, they would add up to 62% and 50.8%. The averages below use that reading.

Purple Fossil — random Beascuits.

The wiki lists the two figures as individual probabilities. Beascuits come in eight types, one per Cookie type, and 8 x (1.875% + 10.625%) is exactly 100%. So a Purple Fossil is always an Epic or a Legendary, and a Legendary of one specific type is 1 in 53. For which type is worth keeping, see our Beascuit tier list.

Amber Fossil — gear upgrade items.

That is one Butter Amber per 20 Amber Fossils on average — the material that guarantees an Epic Topping Tart in the Workshop, and which the Mine Shop caps at 20 a week.

Emerald Fossil — Cookie upgrade items.

The Emerald's headline is 16.55 Rainbow Cubes per Fossil on average, with a 23.9% chance of Cubes on any one appraisal — the Costume Gacha currency covered in our costumes guide. The Pristine Skill Powder line is the other one to notice: Pristine is the top powder tier, the one our Skill Powder guide puts behind the Level 41 wall.

The Workshop and the Mine Shop

The Mine Workshop crafts Topping Tarts from Flour Stone, Sugar Ore and Butter Amber, and breaking Tarts down returns Tart Essence for the Mine Shop, which resets every 7 days. The recipes, the July 29 odds change, the shop's prices and the Tart Cores x100 item added on July 29 are all in our Topping Tarts guide. The one number to carry over here: the Mine Shop sells Butter Amber at 200 Tart Essence, 20 a week, per cookierun.wiki's Mine Shop table. At that price, an Amber Fossil's 5% Butter Amber roll alone is worth 10 Tart Essence per Fossil on average.

What the August 26 update changed

Devsisters' notice lists these Mine changes. Neither wiki reflects all of them yet:

A Mines routine that wastes nothing

1. Refill the Agar Cube slots first. Three slots, 6 to 12 hours each, and an empty slot is melt time you don't get back.
2. Clear every Battle Card inside three days. They expire, failure keeps the card, and cleared battles finish instantly with Time Jumpers.
3. Rest the Venture crew on Quick Rest Seats. Since August 26 a Venture only takes full-HP Cookies, and the seats double recovery speed for four of them.
4. Staff veins by Trait, then by Trait pair. The Trait is the entry ticket on Rare and Epic veins; a Cookie holding both of a vein's Traits stacks efficiency and HP savings.
5. Send Venturous and Brawny Cookies exploring, Tenacious, Musical and Intuitive ones mining. Venturous, Tenacious and Intuitive each carry a penalty on the other job.
6. Break down Ore Vein Cards you can't staff for Radiant Ore Vein Crystals.
7. Load a Razor-Sharp Greatsword or Clunky Wrench when you have one; both turn a Venture into an extra card.
8. Read Fossils by colour. Purple is Beascuits (15% Legendary, never below Epic), Amber is gear materials and a 5% Butter Amber, Emerald is mostly Rainbow Cubes, Pristine Skill Powder and Sugar Crystal chests, at 23.9% each.

Quick Action Checklist

1. Unlock Into the Depths at Cookie Castle Lv.6 (3 Aurora Pillars, Bricks and Compasses).
2. Keep three Agar Cubes melting at all times: Epic-tier cubes hold Beast or Ancient Soulstones and take 12 hours.
3. Play every Mine Battle Card before its 3-day expiry; use Time Jumpers to clear repeats.
4. Count Cookie Battles as a Radiant Beascuit Dough source too: 1, 2 or 4 per battle by tier.
5. Use Agar Agar Cookie on any Rare or Epic vein whose Trait you lack — No Trait ignores vein requirements.
6. Collect Sloth Yeast Ore from Balloon Expeditions to Beast-Yeast Episodes 9 and 10 to cut melt times by up to 30%.
7. Treat each Purple Fossil as a 15% Legendary Beascuit roll and each Amber Fossil as a 1-in-20 Butter Amber.
8. Use the August 26 Recovery Tool values (50 and 100 HP), not the wikis' old snack numbers.