In regards to surveying, I always felt that, considering it's shown that way on both the Nostromo and dropship, they use that wire-frame topographical interpretation to do so. Considering how alike the derelict is to the many bone-shaped rocks, I could see automated software assuming they're all one and the same geographical feature and not prosecuting that area very much further.
River of Pain suggests that the company knew only roughly where the signal was coming from and established a colony on Archeron in the hopes it was the right place. (Which begs the question why wasn't LV-223 investigated?) But why do they only now have a rough idea of its location?
Oh, boy... I'm going to love
reading through that one, I can just tell.
"Gentlemen, we suspect a highly-valuable prize is on this
, my fellow evil Capitalist friend. Let us... Place a civilian colony there!"
"Masterful, Sir! If we're lucky, we should see results in mere centuries - nay, decades
"Or we could send out a small fleet of dedicated survey and retrieval vessels to avoid the ramifications of allowing future non-employees to potentially-"
"No! You've convinced me! We can call it... PROJECT INCOMPETENCE."
"And we won't even tell them
... In fact, if communication gets suddenly cut off, it'll be so low-priority, we won't even intervene before the government is obligated to. The scheme is perfect