What dumped out of my gas tank?

[oil pan 4]

1999 dodge Dakota with 176,000 miles 5.2l engine and the original fuel pump I think. Old fuel pump appears to be original and is making a whining noise so time for a new one.
It looks like ground up rubber and feels like carbon, as if it's ground up coal.
Charcoal canister contents?
Idkwtf it is but it ain't supposed to be in there.
I drove it 7 miles past zero miles till empty and it still had 2 gallons in the bottom.

 

[eljefino]

I like your charcoal canister theory. Guess if the valve lineup doesn't go to plan the tank can suction it.

 

[ripcord]

I like the charcoal theory, too, though could it be rubber from the fill hose?

 

[Rand]

making a whining noise? I have alot of cars with those...

 

[oil pan 4]

I like the charcoal theory, too, though could it be rubber from the fill hose?

It looks like ground up rubber but definitely feels like coal or charcoal. It doesn't grind up into dust as easy as I would expect charcoal to.

 

[oil pan 4]

Upon closer inspection it appears to be like a varnish or resin and probably not charcoal.
Probably came from a sketchy repurposed farm gasoline tank.