Camped this mob for around 2-3 hours. Spawn time is 16 mins, a Dirtdigger assassin, a Dirtdigger umbramaker, a Dirtdigger mender, and a Dirtdigger bonecracker were the mobs that spawn in the above /loc, no named during that time.
Update
Around hour 4 the named spawned and dropped the helm i was after. /loc given is 100% correct.
Edited, Jan 26th 2018 7:07pm by Soulkin