Missing disk space in AIX

i have an AIX server.. where the partition supposed to have 39gb worth of space..
but when i do a df -k, it shows that i have used up almost 24gb of space…
but as i listed out everything under that mount point.. the size of the files does not worth that much of space.. so where did the space went missing to?

$ 
$ df -k
Filesystem    1024-blocks      Free %Used    Iused %Iused Mounted on
/dev/hd4           131072      4720   97%     1724    59% /
/dev/hd2          1703936    541252   69%    34662    22% /usr
/dev/hd9var        131072     76636   42%      484     3% /var
/dev/hd3          1048576   1045528    1%       94     1% /tmp
/dev/hd1          2097152   1361216   36%    16565     6% /home
/proc                   -         -    -         -     -  /proc
/dev/hd10opt       131072     46644   65%     1530    13% /opt
/dev/lvlos        3145728   2677572   15%     8528     2% /los
/dev/lvu01       16908288  10989512   36%    19273     1% /u01
/dev/lvu02       40894464  14807568   64%       12     1% /u02
$ pwd
/
$ cd /u02
$ pwd
/u02
$ ls -lRa
total 24
drwxrwxrwx   5 root     system          256 Oct 03 13:45 .
drwxr-xr-x  21 root     system         4096 Nov 11 14:55 ..
drwxrwxrwx   2 root     system          256 Oct 04 15:31 db_dump
drwxr-xr-x   2 root     system          256 Sep 24 2009  lost+found
drwxrwxr-x   2 oracle   oinstall       8192 Nov 16 07:07 oradata
./db_dump:
total 0
drwxrwxrwx   2 root     system          256 Oct 04 15:31 .
drwxrwxrwx   5 root     system          256 Oct 03 13:45 ..

./lost+found:
total 0
drwxr-xr-x   2 root     system          256 Sep 24 2009  .
drwxrwxrwx   5 root     system          256 Oct 03 13:45 ..

./oradata:
total 1169688
drwxrwxr-x   2 oracle   oinstall       8192 Nov 16 07:07 .
drwxrwxrwx   5 root     system          256 Oct 03 13:45 ..
-rw-r-----   1 root     system         1994 Mar 01 2010  PJ_UAT_bkcrontab_without_gzip
-rw-r-----   1 root     system         2060 Mar 01 2010  PJ_UAT_crontab_with_gzip
-rwxrwxrwx   1 root     system    598843639 Nov 14 20:49 abmb_glos_uatlosdb_20110105_0200.dmp.gz
-rw-r-----   1 root     system          269 Mar 01 2010  alc_sizing.sh
-rw-r-----   1 oracle   oinstall        245 Nov 23 2009  import.parfile
-rwxrwxrwx   1 root     system           48 Mar 01 2010  pj_uat_gzip_dump_files.sh
$ 

any help will be very much appreciated.