> For the complete documentation index, see [llms.txt](https://light-in-the-dark-1.gitbook.io/litd/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://light-in-the-dark-1.gitbook.io/litd/core-in-game-buildings/resource-buildings.md).
# Resource Buildings
The Lumber Mill, Rock Quarry, and all three Mineshafts make up the games core resource structure. Each resource building produces a raw mineral that sometimes needs to be refined in order to be used for crafting purposes. Resources are used in multitudes of ways and are not just used for crafting, so be sure to keep some on hand for basic uses.
The Lumber Mill
The Lumber Mill, Rock Quarry, and Iron Mine are all provided to players at game start, and there is no cap to their leveling system. This means if a player so chooses, they may max upgrade any of the resource buildings at any time regardless of hometown level or library knowledge. This was done to prevent the possibility of limiting any players resource production.
The Rock Quarry
### All resource buildings have the same upgrade system.
There are 9 total overall levels for each building, with 15 sub-levels within each of the 9. Each sub-level can be upgraded in two ways, quantity and efficiency. When you reach sub-level 15 of quantity production and upgrade to level 2, the previous stat boosts gained will be erased but you will have a higher starting point. Meaning jumping from level 1 sub-level 15 to a level 2 sub-level 1 will hurt in the short-term but will quickly become worth it as you continue upgrading.
**Max sub-level quantity upgrades are required in order to upgrade to the next level. Efficiency upgrades are optional to the player.**
The Mineshaft
**Resource Building Upgrade & Unlock System:**
Building Level
Quantity Effect
Efficiency Effect
1
6% increase
3% increase
2
6% increase
3% increase
3
6% increase
3% increase
4
6% increase
3% increase
5
6% increase
3% increase
6
6% increase
3% increase
7
6% increase
3% increase
8
6% increase
3% increase
9
6% increase
3% increase
10
6% increase
3% increase
11
6% increase
3% increase
12
6% increase
3% increase
13
6% increase
3% increase
14
6% increase
3% increase
15
6% increase
3% increase
---
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