I have large piles of topsoil piled up after scraping the topsoil off a building site a few years ago. This topsoil is full of rocks and I am using the topsoil for ground preparation around another site on the ranch. I estimate the unsifted 'dirt' is about 30+% rocks ranging from 3/4 inches to more than 1 foot in diameter.
I had seen a number of the slanted racks for separating the rocks from the soil but it required me to weld up a frame and attach a screen(s) to it to separate. Instead what I did was use some old 2x10's I had laying around, built two frames that I sandwiched one on top of the other with a small overlap (the smaller frame frame is on the bottom with a small overlap) and plywood corner triangular braces for strength. Between the two boxes I attached some bull wire (for strength) and covered it with hardware cloth . The larger frame becomes the dumping box, the bottom is really just to support the wire screens and to get a gap under the top frame and the grade. The whole contraption is about 8 feet by 3 feet and about two boards tall less overlap,
To use the contraption I fill the top compartment with my FEL from my JD 5075 and then I pick up the box contraption with my bobcat fitted with forks. I bounce the boxes up and down with the bobcat and after it just has rocks remaining I go dump the rocks in a big pile by tipping the box contraption. After about 3-4 loads of dirt/rocks I scoop up the sifted dirt and move it the final destination. I can do about 14-20 FEL loads of dirt an hour this way. Cost me nothing in materials as it was all surplus stuff from around the ranch. The sifted dirt is virtually rock free and quite usable for the garden/lawn area.
