The fastest way to mine minerals is to put three SCV’s on each mineral patch. Three SCV’s will maximize the percentage of time that the mineral patch is being utilized. Any more than 3 SCV’s will not produce any extra results, unless the mineral patch is far from the command center, as is the case when remote mining. The rest of this post explains why three SCV’s is fastest, and reports the results of an experiment where the mining rates were measured for different numbers of SCV’s.
Only one SCV can harvest a given mineral patch at once. If two SCV’s are sent to mine a mineral patch at once, one of the SCV’s will begin mining, while the other waits for the first to finish. Any time that a mineral patch is not being mined by an SCV, it is not being utilized, which is a wasted opportunity to increase the harvesting rate. For example, when a mineral patch has only one SCV dedicated to it, all of the time the one SCV is travelling to and from the command center is time that another SCV could be mining from the patch. Adding a second and third SCV will ensure that the mineral patch is constantly being utilized. But after adding the third SCV, the mineral patch will be mined constantly, and adding a fourth SCV will not increase the amount of time the patch is being utilized, and therefore will not increase the harvesting rate.
The following relation summarizes the above and is satisfied (evaluates to true) if and only a mineral patch is being constantly utilized:
On the Steppes of War map, I timed the amount of time it took to mine 200 minerals using one, two, and three SCV’s. The first row in the table below shows the amount of time, in game seconds, it took to mine the minerals. The second and third rows show the mineral mining rates. The last row shows the amount the mining rate increases by adding each SCV.
The values from the table are not going to be the same for every mineral node, depending on the distance from the command center to the node. Adding the third SCV didn’t produce the same increase in mineral rate as the first and second SCV, but it came close. In the future I’m going to look at the other mineral nodes to see how they compare.