Excuse me? Can anyone help me please?

I've just finished a side/sub quest for "The Companions" where I had to rescue Omluag http://www.uesp.net/wiki/Skyrim:Omluag
from the Halted Sream Camp where he was captured by some bandits. I rescued him, and brought him back to the warrens in Markarth where he appreantly resides.

But then.... after he thanked me for bringing him back, he went on to talk about his boss, Mulush gro-Shugurz (an orc fighter)
http://www.uesp.net/wiki/Skyrim:Mulush_gro-Shugurz
and about how he will kill him (or something like that) if he doesn't continue his work.
So then Omluag gave me a little sub/side quest to go and speak to Mulush gro-Shugurz to sort this little problem out for him.
It's this little quest. http://www.youtube.com/watch?v=17ESnpbri5c

But there lies my big problem...... I have looked ALL over the place for that darned orc, and cannot find him anywhere!
He isn't in the Overseers House. :-/ I've checked there.
Also, when I click on the quest name in my quest log, (it's a "rescue mission") nothing happens.
I was expecting the game to move the map towards the location on where to find Mulush, but like I said, nothing happened.

In the youtube link I provided above, a random person said they killed Mulush when they broke out of prison.
This might be similar to what I did, though I'm not 100% certain.
Wasn't there some quest which involved Mulush and looking for someone in the prisons somewhere?
I don't remember 100%, but I'm fairly certain I completed a quest of this description I think.

Could anyone provide a link to what the quest was if they know which one I'm talking about please?
If I've killed Mulush already, then I'd like to go back and find him. (if possible)
This will finally put my mind at rest as to where on earth he has disappeared to!

It just seems that I also cannot talk to Omluag to complete the quest to say that I've dealt with him, as he just says somethijng like,
"need anything." :-/

Can anyone help me out here please?

He usually spends the Day standing near the Smelter outside of Cinha Mine in Markarth. My character has done the quests involving Cindha Mine, but I escaped at Night. He was apparently sleeping, and did ot get involved in stopping Madenach and his Forsworn.
He can get killed by an irresponsible/unlucky player during the questline involving getting thrown into the Mine and escaping with Madenach.

Thank you for your reply.

That's very strange indeed! :-/
Firstly, all around the smelter outside of Cidhna Mine is another place I've already looked...... he's nowhere to be seen there!

Secondly,

The last part of your reply describing the quest about getting sent to prison, and then starting [url=http://www.youtube.com/watch?v=Iat7U7KacnA]"No One Escapes Cidhna Mine"[/ur] is the exact quest I was trying to think of. But STILL..... where on earth is Mulush gro-Shugurz in that quest!?
There's absolutely no sign of him whatsoever!

I've also searched few other clips on youtube related to this quest too.
But I STILL...... cannot find that damed orc!!

Where abouts in the quest does he appear?
Do you (or anyone else out there) have any ideas please?