Similar issue with a 13,2 iMac (Mavericks) with Thunderbolt attached drives (2 x WD 3TB sata drives in a RocketStor rs5212 dock). Unmount seconds to minutes after mounting. Drives work ok in an old G4 mac via native SATA connection.
15/04/2014 11:16:10.000 am kernel[0]: IOThunderboltSwitch<0xffffff80210d6000>(0x0)::listenerCallback - Thunderbolt HPD packet for route = 0x0 port = 1 unplug = 1
15/04/2014 11:16:10.000 am kernel[0]: Fixing incorrect zfree from zone kalloc.16 to zone kalloc.32
15/04/2014 11:16:16.000 am kernel[0]: IOThunderboltSwitch<0xffffff80210d6000>(0x0)::listenerCallback - Thunderbolt HPD packet for route = 0x0 port = 3 unplug = 0
15/04/2014 11:16:18.000 am kernel[0]: [ PCI configuration begin ]
15/04/2014 11:16:18.000 am kernel[0]: [ PCI configuration end, bridges 15, devices 17 ]
15/04/2014 11:16:40.007 am diskarbitrationd[17]: Synk Engine [70]:48899 not responding.
15/04/2014 11:16:40.000 am kernel[0]: jnl: disk0s2: replay_journal: from: 4595712 to: 5492736 (joffset 0x2bae000)
15/04/2014 11:16:40.000 am kernel[0]: jnl: disk2s2: replay_journal: from: 2187264 to: 2768896 (joffset 0x2bae000)
15/04/2014 11:16:40.000 am kernel[0]: jnl: disk2s2: journal replay done.
15/04/2014 11:16:40.000 am kernel[0]: jnl: disk0s2: journal replay done.
15/04/2014 11:16:40.000 am kernel[0]: hfs: mounted 3TB B on device disk2s2
15/04/2014 11:16:40.000 am kernel[0]: hfs: mounted 3TB G on device disk0s2
15/04/2014 11:16:41.325 am NetAuthSysAgent[1946]: DNSAddressResolver:Resolve CFNetServiceResolveWithTimeout failed
15/04/2014 11:16:41.325 am NetAuthSysAgent[1946]: ERROR: AFP_GetServerInfo - connect failed 64
15/04/2014 11:16:41.857 am fseventsd[50]: requested timestamp is prior to the earliest log file. setting event-id to zero
15/04/2014 11:16:43.000 am kernel[0]: [ PCI configuration begin ]
15/04/2014 11:16:43.000 am kernel[0]: [ PCI configuration end, bridges 13, devices 17 ]
15/04/2014 11:16:43.000 am kernel[0]: disk2s2: no such device.
15/04/2014 11:16:43.000 am kernel[0]: disk2s2: media is not present.
15/04/2014 11:16:43.000 am kernel[0]: disk2s2: media is not present.
15/04/2014 11:16:43.000 am kernel[0]: disk2s2: media is not present.
15/04/2014 11:16:43.000 am kernel[0]: jnl: disk2s2: do_jnl_io: strategy err 0x6
15/04/2014 11:16:43.000 am kernel[0]: jnl: disk2s2: write_journal_header: error writing the journal header!
15/04/2014 11:16:43.000 am kernel[0]: disk2s2: media is not present.
15/04/2014 11:16:43.000 am kernel[0]: disk2s2: media is not present.
15/04/2014 11:16:43.000 am kernel[0]: disk0s2: media is not present.
15/04/2014 11:16:43.000 am kernel[0]: jnl: disk0s2: do_jnl_io: strategy err 0x6
15/04/2014 11:16:43.000 am kernel[0]: jnl: disk0s2: end_transaction: only wrote 0 of 81920 bytes to the journal!
15/04/2014 11:16:43.000 am kernel[0]: disk2s2: media is not present.
15/04/2014 11:16:43.000 am kernel[0]: disk2s2: media is not present.
15/04/2014 11:16:43.000 am kernel[0]: disk2s2: media is not present.
15/04/2014 11:16:43.000 am kernel[0]: disk2s2: media is not present.
15/04/2014 11:16:43.000 am kernel[0]: disk2s2: media is not present.
15/04/2014 11:16:43.000 am kernel[0]: disk2s2: media is not present.
15/04/2014 11:16:43.000 am kernel[0]: disk2s2: media is not present.
15/04/2014 11:16:43.000 am kernel[0]: disk2s2: media is not present.
15/04/2014 11:16:43.000 am kernel[0]: disk2s2: media is not present.
15/04/2014 11:16:43.000 am kernel[0]: disk2s2: media is not present.
15/04/2014 11:16:43.000 am kernel[0]: disk2s2: media is not present.
15/04/2014 11:16:43.000 am kernel[0]: hfs: unmount initiated on 3TB G on device disk0s2
15/04/2014 11:16:43.000 am kernel[0]: jnl: disk0s2: close: journal 0xffffff802127c8e0, is invalid. aborting outstanding transactions
15/04/2014 11:16:43.000 am kernel[0]: disk2s2: media is not present.
15/04/2014 11:16:43.000 am kernel[0]: disk2s2: media is not present.
15/04/2014 11:16:43.000 am kernel[0]: disk2s2: media is not present.
15/04/2014 11:16:43.000 am kernel[0]: disk2s2: media is not present.
15/04/2014 11:16:43.000 am kernel[0]: disk2s2: media is not present.
15/04/2014 11:16:43.000 am kernel[0]: disk2s2: media is not present.
15/04/2014 11:16:43.000 am kernel[0]: disk2s2: media is not present.
15/04/2014 11:16:43.000 am kernel[0]: disk2s2: media is not present.
15/04/2014 11:16:43.000 am kernel[0]: disk2s2: media is not present.
15/04/2014 11:16:43.000 am kernel[0]: disk2s2: media is not present.
15/04/2014 11:16:43.000 am kernel[0]: disk2s2: media is not present.
15/04/2014 11:16:43.000 am kernel[0]: disk2s2: media is not present.
15/04/2014 11:16:43.000 am kernel[0]: disk2s2: media is not present.
15/04/2014 11:16:43.000 am kernel[0]: disk2s2: media is not present.
15/04/2014 11:16:43.000 am kernel[0]: disk2s2: media is not present.
15/04/2014 11:16:43.000 am kernel[0]: hfs: unmount initiated on 3TB B on device disk2s2
15/04/2014 11:16:43.000 am kernel[0]: jnl: disk2s2: close: journal 0xffffff802127c740, is invalid. aborting outstanding transactions
15/04/2014 11:16:43.166 am Finder[562]: CreateWithFileInfo failed to create URL with FSRef, falling back to blank icon.