Bilegulch Mine, located in the Southwest portions of Falkreath Hold, is something very valuable to middling-level players who use heavy armor- a mine full of orichalcum, which is used to craft Orcish arms and armor. It should come as no surprise, then, that it is also full of something else: namely, orcish bandits.
Whether you're looking into the place independently or it was brought to your attention, you're going to want to have care here- the orcs in the mine area are powerful and dangerous foes, though remarkably easy to sneak up on and few in number.
The main portion of Bilegulch Mine is actually outdoors, starting as you head upslope towards the place. If you're not cautious, the first of the bandits will rush out of the gate here, coming to lop off your head. You'll want to take him down hard, so he doesn't alert the other two outdoor orcs here and bring them into combat with you at the same time.
In the mine area, you'll find three buildings within the palisade, as well as stairs further up the slope. Ignore the watchpost- there's nothing actually in it- and turn your attention to the nearest hut. The hut contains a few valuables on the shelf, as well as a basket of arrows by the table outside, which is littered with hunting bows. Turn to keep your eye on the stairs as you head for the second hut, as there's an orc standing guard at the top of them who may give you the misfortune of spotting you. The second hut has a chest just outside it, which contains things of far greater worth than the leather boots sitting beside it.
Take the second orc down as quietly as you can- he's got a friend, but that friend is busy working the forge elsewhere on the top level of the mine's fortifications, and you can easily hide from him. Stealth and arrows or an ice projectile work very well for this. If you're sufficiently tough, you may just want to give a bloodcurdling warcry and charge up the stairs at him, which can work if you're heavily armed and armored (and probably looks tons more impressive).