Excavator-based processor operator productivity and cost analysis in Zululand, South Africa
Operator impact on productivity and cost using similar processor machines was addressed in this case study. The study had two objectives: (1) determine the extent of operator productivity variation between six processor operators in a harvesting operation; and (2) determine potential cost implications associated with operator productivity variation. The study was carried out on the Zululand coastal plains near Kwambonambi. A multistem mechanised harvesting system, working in Eucalyptus grandis × camaldulensis pulpwood stands (with an average rotation length of seven years) was observed. The operators had all been operating their respective processors for 18 months; i.e. since the inception of the harvesting operation and had received similar in-house training. Time studies were carried out on the processors' cycle times, and note taken of the respective operators working the machines during the time studies. Cycle time for each machine was measured as the time between a delimbed and debarked tree length leaving the processor head and the following tree length leaving the head. The required number of observations per processor was determined by cycle time and work element time variation. It was found that operators varied by up to 58% in terms of productivity, 24% in terms of utilisation and 70% in terms of cost. The potential difference in cost between using the cheapest operator and the most expensive operator was R9.34 m -3, R4 438 d -1 and R1 384 752 y -1. © 2011 Copyright NISC (Pty) Ltd.