I don't know how long, I got a good 6 hour burn out of about half the ring, it ran at 275F or so for that time. The large chunk of lump at 4 o'clock was my shut-off, I lit the end and burned it counter-clockwise. It burned to 10 o'clock. There is a lot of charcoal in there, so there was enough fuel, I would guess for an easy 8 to maybe 10 hour burn.
I'm feeling bearish, and I'm packing a Wusthof Grand Brisket slicer from MABA
"perhaps...but then again...maybe not..."