How to copy right channel to the left channel?

Windows 7 running Audacity 2.0.2
I have a recording that only has the right channel of a stereo mix. how can I make a 2 channel mix with only 1 channel of waveform data. I could do this in Cool Edit so there must be a way, I am fairly new to Audacity. It’s too late to re-record both channels, the recorder malfunctioned and needs replacing.
Thx all

Use the tools under the little black arrow to the left of the timeline.

Split Stereo Track.

[X] the damaged track.

Select the remaining track by clicking just above the MUTE button.

Edit > Duplicate

Make Stereo Track

This will give you a two-track mono show, not strictly stereo, but it will put something on both left and right speakers. You can also shortcut the process by making the one remaining track Mono after deletion of the bad track instead of duplicating and making stereo. A real Mono show will also come out both stereo speakers.

Koz

Wonderfull, worked well.
Thx Koz