Pumpjack makes stone and ore on reboot
Once you get to place the pumpjack,  it pumps oil, then the server reboots and it starts to do stone and (ore) or (sulfur)
Do you have any other plugins that modify pump jack?

I don't think this problem has anything to do with my plugin.
It's been working on my server.

I had oilcrate.cs.  I removed that plugin (it probably was making the ore in the PJ).  Once the CS was removed. I removed the pumpjack in question. Rebooted the server.  Went through the motions of getting an ore hole then dropping charges to get the oil spot.  Then replacing the pumpjack, and it now pumps and pumps and nothing is in the output.  What I will do is flip back to oilcrate and remove yours and see what happens.  
 
I'll report back later on this