Not Your Standard Time Query

Hello,

I am looking for some help on this query.. I need to find how many minutes are in each 1/2 hour interval for each exception code.. Take a look at the raw data in the attached jpeg..

What I need is by 1/2 hour interval to sum how many minutes of each of the exception codes.. I can use datediff to get the total sum but I need to know by interval..

So for Granted Unpd it would be for example:
Exception Interval Minutes
Granted Unpd 17:00 30
Granted Unpd 17:30 30
Granted Unpd 18:00 30

Attached Images

sample data.jpg (74.5 KB)