Could it be that your plugin prevents placing quarries cause every crater that a survey charge does
 automatically is an oil crater.
Would be great if this could be changed.
I would like the players to be able to place quarries too.
Thank you.

Oh, wait. Is this cause I set "Oil Crater Chance": 100.0 ?

bingo

So, if it's the standard 20 percent, I will be able to place working quarries?

That normal crater has a 20% chance of becoming an oil crater

Ok, great. Will try it again tomorrow after I changed that and see if it works with quarries then.