I worked with this in the beta and I did the mining when I knew we had idiots on the team or people that didn't know how to properly mine.

Why in the hell do you need more than 30 mines on City? You don't. The Barracks is covered by the AGT. The AGT needs five mines.

The back door of the Weapons Factory needs five mines.

That's 10 mines so far.

The back entrance of the Refinery needs five mines. That's 15 mines.

The two entrances on the PP need mines. That's 25 mines.

And last, but not least, the stairway on the PP needs five mines at the front clustered together.

There you go, your base is primed and done.

On Walls? Just mine the Weapons Factory's stairways. Mine its back entrance.

10 mines.

Mine the back entrance of the Refinery.

15 mines.

Mine both entrances of the Power Plant. Mine the stairway.

There's 30 mines. You don't need any more.