I ran a small potbelly coal stove in my basement woodshop for a few years. Only held about 20-25 pounds of coal.
It was diagonally across from the basement stairwell- that had no doors. There was some warm air went up the stairwell as cold air came down. But by the time the warm air reached that side of the basement, there wasn't a lot of temperature difference to cause much convection. And I couldn't move it closer to the center of the basement because it would be in the way of machinery use.
Being such a small stove, it kept the 25x24 basement warm, but could not do enough to heat the rest of the 2 story colonial house (1500 sf). Plus having an acoustic tile ceiling in the basement, and no insulated walls, it likely did more to warm the ground outside the foundation than the floor above.
If I had used a larger stove, then putting in some floor registers to help get the heat to circulate upstairs would have worked better. And insulating the basement walls would have really helped.