So I'm looking at the EDUKY THREE (RNAV) departure procedure at KRIL. With regards to Runway 8.

http://155.178.201.160/d-tpp/1413/06741EDUKY.PDF

Conventional wisdom indicates that this is a normal SID. It does NOT say "OBSTACLE" with inverted colors.

However, if you look at the Takeoff Minimums, it does say "Rwy 8: Standard with minimum climb of 396’ per NM to 11100". Does this mean that because it says "minimum" that you must maintain this rate to 11,100 ft. or else you may impact terrain?

Incidentally, I was under the impression that 396 ft/nm can be reduced by 48 ft/nm to remove the extra safety buffer and that would leave 0 ft. between you and terrain.

Now, when I look at the front of the Instrument Procedures book:

http://155.178.201.160/d-tpp/1413/SW1TO.PDF

Scroll down to "Rifle, CO". Here's what it says...

"RIFLE, CO
GARFIELD COUNTY RGNL (RIL)
TAKEOFF MINIMUMS AND (OBSTACLE)DEPARTURE PROCEDURES AMDT 10 12320 (FAA)
TAKEOFF MINIMUMS:

Rwy 8, std. w/ min. climb of 400' per NM to 11900 or 5400-3 for climb in visual conditions.
"

The Takeoff Mins section at the front of the book uses the same terminology as the SID page namely, "Min. Climb of xxx". Why are the gradients are different? Which one is for terrain and which one is for ATC?

I'd love to find an official FAA document that explains it all but everything I have found is in piecemeal and it seems like terminology is used very roughly.

Thanks everyone.