PARAMETRIC ANALYSIS ON OFF-SHORE DREDGING PROCESS USING CUTTER SUCTION DREDGERS

Abstract

Nowadays, cutter-suction dredgers are widely used in off-shore tin mining around South East Asia region, especially in Indonesia. So far, the effectiveness of the dredging process is arguably due to the skills and experience of individuals who operate the dredgers. No sufficient guidelines, standard operating procedures exist on how to operate the dredgers effectively based on scientific facts and factual data on the mining environment. This paper discusses the effectiveness of the dredging process in a cutter suction dredger (CSD). The influence of various parameters is studied through parametric simulation based on theoretical approach developed by Miedema and Vastbloom, with a number of adaptations from the original model in order to obtain a better approximation. A specific CSD design is used as a case study. From the parametric analysis, it is found that, dredging capacity is highly affected by the cutting thickness and swing speed, rather than the dredging depth. With the limit of pump capacity and dredge power, the optimum cutting thickness is approximately 75% for the dredger in question, adjustable through the swing speed during operation. Moreover, the dredging forces are highly affected by the cutter rotational speed and soil type, whilst lightly affected by the dredging depth. For dredging harder soils, the dredge forces increase by up to 68%, for the dredger in question, hence the operational parameters must be adjusted, i.e. by lowering the swing speed, however maintaining higher rotational speed, in order to have a safe and optimum operation.