Despite my sincerest efforts I cant get the config to zero the lowgrade fuel on the static pumps. Trying 0.0 and -1 in the config still doles out some lowgrade. I know im the minority, trying to make PVE RUST more challenging, but it would mean alot if you could take a look at it for me.
"Mineral Item
Short Name":"lowgradefuel",
"Resource per minutes (pM)": -1
I tried 0.0 as well

It does adjust them, the lowest output i can achieve is 20 lowgrade. 

Just remove the lowgradefuel resource definition
ex.  the static pumpjack config will look like this without lowgradefuel  ( Only crude oil )

"Oil": {
"Mineral Items": [
{
"Mineral Item Short Name": "crude.oil",
"Resource per minutes (pM)": 200.0
}
]
}