I'm guessing that the question is 'Once a song is mixed, are the individual tracks for that song still available?'
The answer is yes. The BR-1180 has 80 tracks of which you can listen to 10 at a time. You decide which 10 by setting the V-Tracks. See page 48 of the BR-1180 manual. Also, see the following page which explains v-tracks in more detail. It was originally written for the BR-864 which has 64 tracks and lets you select 8 at a time, but the principals apply to all multitrack recorders in the BR family, and even to most by other manufacturers.
http://songcrafters.org/64guitars/BR/Tutorials/V-Tracks_and_Bouncing.html
When you create your mix in bounce mode, you specify an empty pair of tracks/v-tracks as the destination. The original source tracks are still there but they may not be selected anymore. To hear them, just re-select the corresponding v-tracks in the v-tracks screen as described on page 48 of the manual.