We really do need more info, and pics, to help you in this. But let's look at it this way, and I do not use the word "assume"-PERIOD! You are removing a coal fired stove in your basement, which means it does indeed, or should, have a vent pipe. This vent pipe has to pass through a wall, a roof or something to vent outside and it sounds as if it is a wall. Now you have the interior wall to patch a hole in and an exterior wall to patch a hole in. SEE-we don't know what the interior wall is comprised of. We do seem to know that the exterior siding is older aluminum, but what is the exterior sheathing made of? The aluminum siding can be patched, not so that it's invisible, but not so noticeable if you take your time and do a good job. Please, more information and I assure you that someone will jump in and give you answers to help you. Thanks, David