Metal Extractor Yield
An extractor's income depends only on the ground under it. The game works it out once, when the extractor is placed, and it never changes after that.
The Ground
The map is divided into small squares, 16 by 16 in the units used for ranges, and each square holds a metal value from 0 to 255. When a map loads, every square gets the map's surface metal value. Each metal deposit, the patch of shiny rocks, then sets the squares it covers to its own value. On the moon maps, for example, a Metal Deposit covers 3 by 3 squares with a value of 112.
The metal in the ground never runs out. However long you mine a square, its value stays the same.
The Rule
A building's footprint covers a whole number of squares: 3 by 3 for the Metal Extractor and 5 by 5 for the Moho Mine. The extractor's income, in metal per second, is:
extraction value × the sum, over every square under it, of (the square's metal + 1)
- The extraction value is 0.001 for the Metal Extractor and the Underwater Metal Extractor, and 0.003 for the Moho Mine.
- Only squares under the footprint count. There is no wider radius, so an extractor half on a deposit gets only the half it covers.
- The +1 means that an extractor on ground with no metal still makes a little.
- The yield is worked out once, when the extractor is placed.
- How fast the dish spins shows the sum, so a faster dish means a richer spot.
The extractor also uses energy: 3 a second for the Metal Extractor, 15 for the Arm Moho Mine, 12 for the Core Moho Mine and 2 for the Underwater Metal Extractor. In a second when that energy is not paid, the extractor makes no metal (see stalls). Its yield is added once a second, at the settle.
Worked Examples
| Ground | Metal Extractor | Moho Mine |
|---|---|---|
| Surface metal 0, no deposit | 0.009 | 0.075 |
| Surface metal 3, as in A Hero Returns | 0.036 | 0.3 |
| A 112 deposit, 6 of the 9 squares covered, surface metal 3 | 0.690 | — |
| A 112 deposit, fully covered, surface metal 3 | 1.017 | 3.243 |
| Surface metal 255, as on Metal Heck | 2.304 | 19.2 |
All figures are metal per second. Take the fully covered deposit: the Metal Extractor covers 9 squares of 112, so the sum is 9 × 113 = 1017, and 1017 × 0.001 = 1.017 metal a second. A Moho Mine on the same deposit covers those 9 squares and 16 squares of surface metal around them: (9 × 113 + 16 × 4) × 0.003 = 3.243.
On even ground the Moho Mine makes 8.3 times as much as the Metal Extractor, because it has three times the extraction value and covers 25 squares instead of 9. On a deposit no larger than the Metal Extractor, it makes only about three times as much, because its extra squares hold only surface metal.
Surface metal is 3 on 70 of the 100 multiplayer maps. On those maps a Metal Extractor away from a deposit makes 0.036 metal a second, and it takes just over 23 minutes to earn back its own 50 metal.
The computer player gets less from the same extractor on Easy and Medium.