Upon your guild reaching level 8 the Mill will be unlocked.
Orders
The best way to get 
Guild Coin, is by using orders. The number of orders available depends on level of the guild mill. Orders can be upgraded to give more rewards, up to a maximum of 6 stars. Upgrading an order costs 
Gems. You can get new orders every 12 hours, regardles if you already completed the available orders.
| Stars | Time | Base reward | Upgrade cost to next star |
|---|---|---|---|
| 1 | 10hrs | 200K  , 90x 
|
10x 
|
| 2 | 10hrs | 250K , 110x
|
20x
|
| 3 | 11hrs | 300K , 140x
|
30x
|
| 4 | 11hrs | 350K , 170x
|
60x
|
| 5 | 12hrs | 400K , 220x
|
100x
|
| 6 | 12hrs | 500K , 280x
|
- |
Upgrade Mill
You and your guild mates will donate 
Gold to upgrade the Mill giving you more Gold and Guild Coins per Order. As of Patch Android 1.11.7 / iOS 1.9.9 the maximum level of the Mill is increased from 6.
| Level | Upgrade cost | Order Yield | # of orders |
|---|---|---|---|
| 1 | - | +0% | ? |
| 2 | 12M
|
+10% | ? |
| 3 | 24M
|
+20% | ? |
| 4 | 48M
|
+30% | ? |
| 5 | 96M
|
+40% | 3 |
| 6 | 96M
|
+50% | 3 |
| 7 | 144M
|
+60% | 4 |
| 8 | 216M
|
+70% | 4 |
| 9 | 324M
|
+80% | 5 |
| 10 | 486M
|
+90% | 5 |