It will probably take quite a while to dry out the fines, especially in the cold garage.. Fines stay wet/damp for months even in the summer and fall.
If you can, screen out the fines.. put them in paper grocery bags, roll up the bag to make a 'log' about 3-4" diameter. The add the 'log' on a hot fire, the fines will burn in one spot, and can be broken up after an hour or so. This is how I burnt up my fines.. when I just shoveled in the mixed coal, the fines blocked too much airflow and I had problems keeping a good fire.
Hope this helps..