Saltpeter Mine
1
x 
12:00
1
x 
As soon as the deposit is fully developed, this building will fall into disrepair and be destroyed. To prevent destruction, you can refill deposits with the following amplifiers: or
Location of deposits:
2x
1x
1x
1x
1x
1x
Upgrade
| Level | Resources | Time | Required | Production |
|---|---|---|---|---|
| 1 |    | 20 minutes | | |
| 2 | | 2 minutes, 30 seconds | | |
| 3 | | 5 minutes | | |
| 4 | | 7 minutes, 30 seconds | | |
| 5 | | 10 minutes | | |
| 6 |  | 10 minutes | | |
| 7 |  | 7 days | | |