Mr. Mine Idle is a popular idle mining game developed by Playsaurus that perfectly simulates the mining experience. Unlike other clicker games or incremental games, you either get rich or die mining.
Among many exciting features, the Underground City stands out the most, as it’s one of the biggest locations you unlock in the game’s early stage.
This guide will show you everything you need to know about the Mr. Mine Idle Underground City, including how to unlock it, the features, and the frequently asked questions about this mysterious city.
The Journey to the Underground City
The Underground City is the 7th milestone in Mr. Mine Idle, unlocked at depths 300-303km.
By the time you reach this depth, a new icon with a pyramid appears in the right column. Like other game features here, this icon works as a shortcut, allowing you to quickly travel to the Underground City with a single click.
The Underground City is a huge milestone in the game, as it unlocked several new resources and game mechanics. This includes:
- Oil Pump and Oil
- The Forge and Gems
- Weapons
- Monsters
- and the Battle mechanic
Now, let’s go into the detail!
Underground City’s Key Structures
The Underground City has 4 clickable buildings: the Forge, the Pyramid, the Oil Pump, and the Armory.
Each introduces new mechanics to the mining clicker game, expanding the gameplay further and allowing you to vary the strategy.
1. The Forge (Shortcut: G)
The Forge is a medium house on the left with 3 big gems on top of it.
Within the Forge, you can craft 5 different types of gems using specific resources and workload. The more workload you allocate to craft a gem, the faster the crafting process is.
You can then upgrade the Forge to bring the maximum workload up to 120.
The table below shows all the gems and their costs:
| Gem | Resources | Time |
|---|---|---|
| Red Gem | 2,000 Red Diamond 2,000 Coal | 10 Minutes |
| Blue Gem | 10,000 Coal 7,500 Diamond 10,000 Blue Obsidian 1 Oil $10 Billion | 1 Hour |
| Green Gem | 10,000 Coltan 10,000 Black Opal 4 Oil $30 Billion | 12 Hours |
| Purple Gem | 25 Red Gem 25 Blue Gem 25 Polonium 2 16 Oil $500 Billion | 64 Hours |
| Yellow Gem | 25 Red Gem 25 Green Gem 250,000 Californium 200 Oil $1.5 Trillion | 288 Hours |
The gems here are then used to upgrade your stats in the Upgrades tab, which can be handy when fighting monsters.
There are five stats to upgrade, including:
- HP
- Energy
- Energy Regen Per Turn
- Cards Draw Per Turn
- Max Cards In Hand
Moreover, timelapses also affect the gem-forging time. So, to maximize efficiency, it’s advisable to regularly check the Forge after some timelapse usage rather than using all timelapses at once.
2. The Pyramid (Shortcut: Q)
Once you reach the 300km depth and unlock the Underground City, you automatically unlock another 15 quests (or achievements).
The new quests can then be accessed through the Buff Guy at the top of your mineshaft or by clicking the Pyramid in the Underground City.
3. The Oil Pump (Shortcut: O)
The Oil Pump is located in the center of the Underground City, below the Pyramid. It has one and only one function, which is to extract Oil from the ground.
Oil is an essential resource used for many upgrades, allowing you to progress deeper into the idle minibg game.
The Oil Pump can be upgraded through the Craft Center to increase the Oil Capacity as well as the Oil Extracting Time. When you first unlock the Oil Pump, it takes 7,200 seconds to gather 1 Oil and can only store 1 Oil max.
Overall, you should prioritize upgrading the Oil Pump, as it’s used in many other features in Mr. Mine.
4. The Armory (Shortcut: W)
Besides unlocking the Underground City, reaching 300km of depth also unlocks a new game feature – Battles.
Monsters will regularly spawn at a random mineshaft, just like chests. And your mission is to click on the monster (with a red exclamation icon) to initiate the battle.
Yes, you guessed it! In order to battle, you must have weapons.
Luckily, Mr. Mine provides you with a lovely Fist to punch the monsters lurking in the mineshaft when you first reach the Underground City. Later on, you can unlock more weapons by opening battle chests, killing monsters, and completing scientist missions.
Unlock weapons is just a small step; you need to upgrade them to become more powerful and easily defeat the bosses.
Let’s come to the Armory, which is a mighty statue located on the right of the Underground City.
Here, you can manage all of the weapons you own, upgrade them, or unlock new ones. Each upgrade increases the damage and effect of the weapon.
Strategic Guide for Navigating the Underground City
When you reach Underground City, you may be overwhelmed by many new features simultaneously. So, here are a few tips to do as soon as you unlock the Forge, the Oil Pump, and the Armory.
You may want to save some resources, especially isotopes and Building Materials, to upgrade the Oil Pump. Then, focus on forging gems to upgrade stats.
While red and blue gems can be forged easily and cheaply, you want to forge a lot of them. Later, you still need red and blue gems to forge other high-quality ones.
As you can see, the whole rabbit hole in the Underground City involves upgrading the Oil Pump to get more Oil, constantly forging gems, and finally, upgrading weapons.
Once you have enough Oil and gems, it’s time to find more weapons.
Try to open as many chests as you can, especially Battle Chests, as they have a higher chance of giving a new weapon.
In addition, use timelapses to finish the scientist excavation mission faster, allowing you to pick excavation with a weapon reward.
In general, it’s recommended to upgrade weapons before battle to ensure victory.
However, you can always test your limit by just fighting the monster, as losing in Mr. Mine doesn’t have any penalty besides the despawn of the monster.
Conclusion
And that’s all you need to know about the Underground City in Mr. Mine Idle.
Let’s now collect materials, forge gems, and upgrade weapons to conquer the mysterious mineshaft! Feel free to contribute to our community or Discord if you have any special strategies or questions.
Good luck exploring our idle mining games, miners!
Frequently Asked Questions
How Far Down Is the Underground City?
As mentioned before, the Underground City is located at 300-303km of depth.
How Does Oil Work?
Oil is another resource in the game, just like other minerals or isotopes. You get Oil overtime from the Oil Pump, which is unlocked at the Underground City. The maximum Oil you can hold varies depending on the oil pump level. So, to store more Oil, simply upgrade the Oil Pump.
What Minerals Should I Save Up for Underground City?
Overall, you should save all isotopes and keep at least 10,000 of all other minerals. However, if you’re running out of the storage room, here is the list of resources you should save for the Underground City:
- Building Materials
- Red Diamond
- Blue Obsidian
- Coltan
- Black Opal
- Californium
- Polonium 2
- Uranium 2
- Plutonium 2
