"873690064 KB in bad sectors."

I got an adapter for my external 2TB RAID array so I could use Firewire (it uses a 6-pin cable, laptop uses 4-pin port). I had it on a USB port previously, but now that I'm not using it, I decided to remove the USB cable from the enclosure. Well, I pulled the power cord by mistake instead.
Fortunately Windows comes with a handy little tool called chkdsk. Knowing that NTFS is pretty robust, I ran chkdsk with the /B switch (the works, basically) hoping I wouldn't lose anything. Well, 21½ hours later (it really took that long) I find that all my data is fine, but now I have 850GB+ of space that I can't access (see thread title). None of it shows as a file.
chkdsk O: /V
The type of the file system is NTFS.
Volume label is Storage 4.

WARNING! F parameter not specified.
Running CHKDSK in read-only mode.

CHKDSK is verifying files (stage 1 of 3)...
161984 file records processed.
File verification completed.
0 large file records processed.
0 bad file records processed.
0 EA records processed.
0 reparse records processed.
CHKDSK is verifying indexes (stage 2 of 3)...
181072 index entries processed.
Index verification completed.
0 unindexed files processed.
CHKDSK is verifying security descriptors (stage 3 of 3)...
161984 security descriptors processed.
Security descriptor verification completed.
9544 data files processed.
Windows has checked the file system and found no problems.

1953522687 KB total disk space.
1000699904 KB in 123055 files.
93488 KB in 9546 indexes.
873690064 KB in bad sectors.
242927 KB in use by the system.
65536 KB occupied by the log file.
78796304 KB available on disk.

16384 bytes in each allocation unit.
122095167 total allocation units on disk.
4924769 allocation units available on disk.
I have nearly a terabyte of data on the array. I'd just reformat, but I don't have nearly enough free space on my other drives to back it all up.

Any ideas? I'm running chkdsk on it again with the /R switch, but it's probably going to take another 20 hours to finish, and it'll likely be worse if I stop it.