How to mount an lvm, volume from ubuntu livecd

Install lvm2 tool, if the distribution cd does not have it.  For 15.04, it's already there.
 
apt-get install lvm2

fdisk -lu

 
pvscan

vgscan

vgchange -a y


lvscan


Now, mount the volume to any directory you want.
 mount /dev/VolGroup00/LogVol00 /mnt