This report describes a study of the efficiency of operation of earthmoving plant on road construction sites. Descriptions of the techniques used in the site observations and methods of analysis of the data are included. The results show that losses in efficiency totaled 37 per cent of the overall machine time observed. This figure does not include the "slowing down" effects due to adverse soil conditions. About half of the losses (19 per cent) occurred while the machines were empty, i.e. returning from the fill to the excavation area, while only 5 per cent was lost during the loaded part of the earthmoving cycle. The remainder of the losses (13 per cent) were associated with machines that were absent from the earthmoving operations, usually in the plant yard undergoing repair. Main reasons for lost efficiency were the delays associated with machine availability (about 15 per cent). other major causes of losses in efficiency were operating the machines more slowly than usual (6 per cent), waiting for load assistance (6 per cent) and delays associated with the operators (5 per cent) .(Author/publisher)
Abstract