Whilst trying to do Boethia's Calling, my girlfriend and i found out that there's a wall of corundrum ore that is blocking the way down to the mine itself from the room with the cage and a dead imperial, a levelled bandit, and a levelled chest, to get the Champion of Boethia. I have had issues before with games such as Fallout New Vegas (whose repeated crashes made it unplayable). Im a huge fan of the Elder Scrolls, but its starting to become a real test of faith. In general, has
A ) anyone else had this issue?
B ) is there another way into the Mine at all?
C ) if there is a genuine reason on how to get into the Mine from the starting room, what is it? repeated walkthroughs have shown that path with no wall and no obstructions.

Try to exit and then re-enter the mine. This often resets/clears the passage.
See this link: http://www.uesp.net/wiki/Skyrim:Knifepoint_Ridge
In particular, check the Bugs section at the bottom of that page.
Hope that helps