If it is a sifting conveyor, then it may be used for sifting through the evidence in the soil.
When you scroll down the page to "9.0" on this link, tell me if you think it looks similar to this:
http://www.stanley.army.mil/Volume1...as/AOC36_mustard_gas_investigation_report.htm
I'm glad you only said 99% sure because I think it's a tilt flatbed truck. Where I work sometimes we need a bigger tow motor than what we have, and when they deliver it, it's on a flatbed that tilts up about 45 degrees and then slides down behind the truck horizontally, and then the tow motor is just driven off at ground level.
Very similar to the one in this aerial shot of DM's farm
That orange plate is probably the bed, and it looks like there's a piece of equipment still on it.
http://www.gettyimages.ca/detail/ne...vestigating-death-of-tim-news-photo/168745468