In this photo you can see that after 4 days the anode has eroded even further, and that the erosion is not even. Why the right hand side is eroding more than the left is not clear. It could be because of the position of the crocodile clip, it could be that the coin on the other side of the charcoal disc is off centre, or it could be for some other reason. In this photo you can see the copper wire mentioned in an earlier log entry that will prevent the centre of the anode becoming electrically isolated from the rim.
The cell seems to be able to produce a steady 5mW, and has done so for 4 days. So far it has provided about 4*24*3600*0.005 J = 1728 Joules of energy. For comparison, a Zinc Carbon AA cell (the lowest capacity primary AA cell available) can provide about 5000 Joules.