WD My Passport 0820 USB HFS+ data disk drive partition problem following accidental use of Recovery Assistant I have edited this post in view of recent developments

I have a 2 TB USB Disk used for all my data. I accidentally ran Lion Recovery Disk Assistant on it, instead of my Pen Drive, to make a bootable installer. Now I can't mount the disk.

Disk shows up in Disk Utility 


Now surprisingly one of the folders showing up from the corrupted USB HD 2TB  but the folder is empty



Last login: Mon Jul 18 14:48:54 on ttys000
bash: alias: ll-ls -lahG: not found
sanjeevvyas$ diskutil list
/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *251.0 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:                  Apple_HFS MacPro HD               250.1 GB   disk0s2
   3:                  Apple_HFS Blank                   650.0 MB   disk0s3
/dev/disk1 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *2.0 TB     disk1
/dev/disk2 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *1.0 TB     disk2
   1:                        EFI EFI                     209.7 MB   disk2s1
   2:                  Apple_HFS ELEMENTS                999.8 GB   disk2s2
sanjeevvyas$

Ideally /dev/disk1 should have the same partition structure as /dev/disk2 .I am missing 2 partitions, is there anyway I can fix the partition structure?

I have tried TestDisk, Data Wizard and Disk Drill, however nothing has helped.
OS X Recovery Disk Assistant v1.0

If you allowed that assistant to complete its work on the wrong disk (with your data) then it's reasonable to assume that hundreds of megabytes of your data were overwritten. However, from your screenshot it appears that the WD My Passport 0820 Media does still contain a VideoUSBPASS1TB volume; so maybe the assistant was unable to proceed with a drive that uses hardware and/or firmware encryption. 

I suggest taking advice from Western Digital …