Black & Veatch Instrumentation & Controls Engineer interview questions

Met at the College career fair (Michigan Tech). They called up for interview next day. Half hour slots. Interview was pretty basic. Behavioral questions all the way (Don't you just hate em?). The guy who was interviewing was a recent alumni so I was pretty relaxed. He made it clear that it's just the screening process. If passed, I will have to go to Ann arbor for the HR + Technical Interview, and that they will be letting us know in Two weeks time whether or not we made it or not. Three weeks have passed, Nothing. Black & Veatch is a huge company. They come to EVERY career fair at our campus. Whats the point of making the effort, interviewing so many people, yet not going forward with it. Just wondering.