
n civil engineering, pob tseg tsheb thauj khoom feem ntau ua hauj lwm ua ke nrog excavators, loaders, siv conveyors thiab lwm yam kev tsim machinery tsim loading, thauj thiab unloading ntau lawm kab rau lub loading thiab unloading ntawm lub ntiaj teb, xuab zeb thiab tej ntaub ntawv.