I saw that to the some pgtour players they found some negative appearance that check the position of the minerals, I wanted to know which is the just manner to place them.
I already knew for quite a long time that there are differences in mining speed. As far as I know, the time a peon needs to chop those 8 mins out of the patch is different, but I can't really tell for sure. At least this would explain why you can mass a lot more probes and still get better mining speed compared to other races.
But since it is not important how fast the different races mine ore - this is balanced out within the whole game - you need to test with only one race at a time when balancing out mining speed.
I found that it works pretty good if you place an additional starting location somewhere in the middle (not on an island if it's a ground map, might change the AI), and play a game with 2/4/... computers of the same race FFA (restart until you are in the "middle"). After 5 minutes or so (about when the first attack comes) you type "there is no cow level" and compare the minined resources. Of course you should use "black sheep wall" as well and check if they are really using the same build order. Pretty certain for terran, most certain for protoss (maybe DT rush), and a little less certain for zerg (ling rush). Restart until it works out fine.
Based on the results you get you modify the mineral lines a little (and test again).
You might want to add this to the articles section. It's some research about mining speed and mineral distribution. I don't think it has that many interesting things for map makers apart from the Neo-Forte-Effect, and is more interesting for the gamers, but nevertheless it might prove to be useful.