I have a Kingston USB flash drive that does not automatically mount itself on my SLES server on occasion.  TID 7000951 explains how to mount the drive manually:

1) From a terminal, run:

lsmod |grep usb  make sure usb_storage is loaded.  If it is not, run:
 
 modprobe usb-storage

2) Plug the USB device in and run dmesg.  The results will look like:

USB Mass Storage support registered.
 scsi 6:0:0:0: Direct-Access CRUCIAL USB Flash Disk 2.00 PQ: 0 ANSI: 2
 ready
 sd 6:0:0:0: [sdd] 1017856 512-byte hardware sectors (521 MB)
 sd 6:0:0:0: [sdd] Write Protect is off
 sd 6:0:0:0: [sdd] Mode Sense: 03 00 00 00
 sd 6:0:0:0: [sdd] Assuming drive cache: write through
 sd 6:0:0:0: [sdd] 1017856 512-byte hardware sectors (521 MB)
 sd 6:0:0:0: [sdd] Write Protect is off
 sd 6:0:0:0: [sdd] Mode Sense: 03 00 00 00
 sd 6:0:0:0: [sdd] Assuming drive cache: write through
 sdd: sdd1 <-- THIS IS THE DEVICE NAME
 sd 6:0:0:0: [sdd] Attached SCSI removable disk
 sd 6:0:0:0: Attached scsi generic sg4 type 0
 usb-storage: device scan complete

Look for the kernel device name, in this case, /dev/sdd, with a partition on /dev/sdd1

3) Mount volume manually by running:

mount /dev/sdd1 /mnt

Access the USB drive at /mnt

To unmount the USB drive run:

umount /mnt