SureAI

After I pull the lever and ride the gondola across, I just come into a place and another black ape appears. All I can find is a hallway at the end of which theres a gate and opposite to the gate a large stone blocks the path.

Have you installed the latest patch? I remember some bugs happening at that point with the release version? (Your version displayed at the top of the launcher should be 1.5.0.5). If I remember correctly, you should go through a gate (which then locks behind you) into a room with two levers.
Just in case: If the above doesn't help, deactivate any other mods (if you've got any) and make sure you haven't used "tcl" or other console commands. These often break scripts.

When you get off the moving platform, you go a bit to the right then north. Then you turn right, but do not go to the end of that hall; just after you enter it you turn left, and proceed up then left through a gate which you close behind you. You can consult the wiki at http://nehrim.wikia.com/wiki/Nehrim_Wiki to find maps of the starting mine.

Also, it is the same black troll.. if you watch while riding the gondola, he climbs and runs along the cables as you're riding.