I was working on a requested plugin and noticed that OnQuarryConsumeFuel is rather inconveniently placed.
It's currently right after the if (item != null && item.amount >= 1) check, at the moment you can't really grab when the fuel has ran out.

It would require the hook to be placed before the item.amount >= 1 check, or in MiningQuarry.ProcessResources() at the bottom where the code turns the engine off: if (!this.FuelCheck()) { this.SetOn(false); }