When I type
diskutil mount disk3 in the terminal, it says Volume(s) mounted successfully. However, the disk is not mounted and I can confirm this by opening the GUI of Disk Utility.app and also the disk does not show in the Finder.
I suspect this is because the disk is encrypted and the terminal command is not passing via "Keychain" to retrieve the password for the encrypted disk.
What do you think? Is there a way to mount encrypted disks via the command line?