This CAT777 dumper got stuck in a soft muddy spot and it took a D10 dozer as well as a big loader to get it out. We loaded this dumper with single wheels at the rear because owner was waiting for new tyres to be delivered. To get to the offloading point we have to cross under a bridge which is too low for us to pass under. We then offload before the bridge and the dumper drives under the bridge by its own where we load it again further to offloading point. After passing under the bridge we got stuck in a soft muddy spot. Probably would not have; if we had duals on the rear of the dumper. Dumper is working on Coal mine in South Africa near Johannesburg.