I moved a 20,000 gallon (91,000 litre) concrete water tank in the late 1960's, with my D6C, by dragging it on two big logs.
The tank had become useless because the bore near it, had run dry. So the farmer wanted to move it about a mile (1.6kms) to a new location where he could use it.
I prepared a new pad for it at the new location, then we cut a couple of nice big whitegum logs and took them to the tank.
I slipped a corner of the blade gingerly under the outside lower section of the tank and slowly raised it off the ground.
This tank had been constructed in-situ with forms and was only about 3"-4" (75-100mm) thick concrete.
I fully expected the tank to collapse when I lifted it (and we'd considered that problem and the farmer didn't care if it fell apart, because it was relatively useless to him where it was) - but amazingly, it stayed in one piece (it was mesh reinforced) as I lifted it about 2' (600mm) off the ground.
We rolled the logs under it in a V-fashion and we hooked 2 chains to the logs and coupled them to the ripper on the D6C.
I set off steadily, dragging the tank across smooth hard paddocks (fields) for the entire distance (it was mid-Summer) and when I got to the new site, the tank was dragged onto the new pad, and the log installation procedure was reversed.
We leveled the gouge marks made by the logs and shovelled some sand around under the tank to provide a satisfactory base, then lowered the tank down again.
The operation was 100% successful, the farmer was very pleased, and I believe that tank is still in use.