Unable to alter partitions in Disk Utility

I am trying to partition my internal hard drive to install Linux Mint. However, when I go to the partition tab, the "+" symbol and all other options are greyed out. I had tried to install Linux a a year ago and had partitioned the disk. But i removed that partition. The partitions that are visible to me are Macintosh HD, Recovery HD and an old partition that is in Mac OS Extended. That is there are 3 partitions in all.
I would be grateful for any help! Thanks!

Need to remove the logical volume group (LVG). There are a few tutorials out there - all of them will involve Terminal.

You need to backup your drive prior to doing it. Personally, I wouldn't do it without a cloned bootable backup via SuperDuper! or CarbonCopyCloner that you have also verified as working. I would also suggest you have a USB installer of OS X handy.

I will reiterate, don't do it without a current backup.

To the OP:

If you're going to be installing Linux or doing any kind of partitioning, you might want to buy a tool from Paragon Software called "Hard disk manager". It's a bit pricey at $49.95 but it does non destructive partitioning plus much more. Certainly a lot easier than messing with terminal and possibly losing data.

Thank you! I managed to remove "Partition 2". I could then create a partition for Linux. Somehow, it seemed to have worked out ok!