No NTFS read support in OSX Mavericks?
Mavericks does have read support for NTFS partitions enabled by default. However I doubt the problem is with the NTFS filesystem itself.

More likely the problem is with the partition table on the drive. If you are confident in the use of command line tools you can use TestDisk to attempt to locate and restore the missing NTFS partition. There is a detailed guide here on how to restore missing partitions.

PLEASE NOTE: Before attempting this though I would backup all the data on that drive (using the Mac to backup the HFS+ partition and the Windows laptop you mention to backup the NTFS partition), as a misstep could result in losing both partitions.