I stood looking at my driveway extension just moments ago.

I dont recommend it for use as drainage fill unless you can buy it sized failrly large with all the fines removed...

after it was dumped in my drieway extension it solified into a rock hard surface that rain would run off

Understood. And yes, I agree that if the fines are not removed, it may bind up. But I'm thinking (hoping?) that if it's NO SMALLER THAN l"-2" pieces, and I cover it all with filter fabric, then I should be fine.