Productivity and cost analysis of grapple skidder at Sao Hill Forest Plantations, Tanzania

Abstract

Grappleskidder was introduced by Mufindi paper mill for timber harvesting operations at Sao-hill forest plantation .It aimed at improving skidding productivity and reducing operational costs. However, it was not well known to what extent the machine was efficient in terms of productivity and cost.
Therefore this study was conducted to analyze the productivity and cost of grapple skidder at Sao hill forest plantation. Time and motion studies were used for data collection. Time elements of grapple skidder operations that
were recorded included: travel empty time, grappling time, travel loaded time and unloading time. It was found that the grapple skidder productivity was reduced exponentially with increasing skidding distances. The productivity for skidding operations ranged from 42.2 m3/h to 15.4 m3/h
when the skidding distances were 10m to 125m respectively. Analysis of cost data indicated that, average skidding cost for grapple skidder was 1 875 TZS/m3(1.4 USD/m3). The study concludes that, on the basis of cost effectiveness grapple skidder should prove satisfactory for skidding  operations in Tanzania. These observation suggest that reducing skidding distances through proper planning of skid trails ahead of logging operations and maximization of pay load are more crucial for economic skidding operation using grapple skidder.

Keywords: Grapple skidder, timber harvesting operations, productivity and cost, time study technique