We had drainage problems in the front yard. Basically, the yard slopped from the street to the house, and was covered with two layers of black plastic and rocks. This had the effect of turning our basement into the primary drain for our front yard. Not good with carpet all through the basement. So we had the rocks and plastic scraped off. Something like 80 tons worth. Now I was down to dirt so I started scraping that off to level out the yard. I came across a rock.
I got out a pick and tried to pop it out. Nearly broke the handle of the pick and the rock didn't budge. Got out the tractor, dropped one scarifier down and hooked the corner of the rock. It stopped the trator dead in its tracks. Oh-oh. Time to get out the big guns.
I put the backhoe on the tractor, backed up to the rock and started to dig.
So I called in a big tractor and a big truck. We lost track of the amount of fairly clean dirt we took out. We kept better track of the number of loads that went to the concrete recycle plant. That's right. The concrete that we dug up was surprisingly free of dirt (Colorado clay) so we could load it into the truck and haul it off. The tandem axle dump-truck. We filled that truck up seven times! All told, it took them three days to get the dirt and rock out of our yard.
While the truck ran the last load of dirt off to the dump site, the tractor operator and I were left alone. Since there was one last load of rubble piled in the yard, I figured I would walk around with a pick and pop out any chunks I found. The first piece I found popped right out. The piece next to it nearly broke the pick handle again. I signaled the tractor operator and he came over and used his backhoe to pop up about a 3'x3'x6" hunk of concrete! I found another small rock that once again nearly broke the handle of the pick. Over comes the tractor and out comes a piece of concrete about 4'x5'x8"! The pieces under it were smaller but plentiful. I threw them out of an ever deepening hole but I did finally seem to reach a point where there was no more (obvious) chunks of concrete. That last load of rubble would have only filled the truck about 3/4 full. By the time I was done finding the "little" pieces of concrete there was some concern as to whether we had enough room in the truck or not. We did, but only just.
But now our front yard is at least flat. I have a little berm to build to keep water from the street from rushing through the yard and some planters to build for Nori. That Colorado clay that kept the concrete fairly clean, not so good for growing. But we have a plan for that too. We have three fertilizer factories living in the back yard! We have a rather substantial amount of organic material we can work back into the clay. I wonder how much more concrete I'll find when I start that project.