Strategy to Improve Coal Mining Operation Productivity In Weak Material Challenge Using Dmaic and Lean Six Sigma Method: A Case Study Of Warukin Formation At South Borneo, Indonesia

Abstract

Prepared working area, downtime, limited actual hauler had significant increase in equipment waiting time which has an impact on the less than optimal productivity of the 200-ton class excavator with the potential impact of lost sales revenue opportunities each year of up to USD 13.6 million. Geological conditions with the Warukin Formation & Alluvium Deposits have challenges related to limited working areas, material strength conditions, road formations, and sustainability of operations. This thesis discusses the improvement strategies needed to increase excavator productivity and optimize the performance of its supporting unit equipment so that it can achieve production targets precisely and accurately. The method used is the DMAIC (Define, Measure, Analyze, Improve & Control) and LSS (Lean Six Sigma) methods to determine a systematic framework to increase the productivity of Coal Mining Equipment and encourage sustainable Mining Operational practices. There are 12 root causes based on observations of the 3 aspects that most affect the productivity of equipment performance, namely management of material, technical, and supervision. The actual productivity of 200-ton excavator is 665/hour with a Sigma Level value of 1.9 and Cpk value of 0.14. The achievement of the productivity of 200-ton excavator has a significant correlation and have incremental impact with Speed 45.45%, Match Factor 40.43%, and Condition Material 10.56%. Multivariate regression analysis has been carried out on the actual condition of loader productivity and is known to have an R-sq value of 81.36% to explain the condition of actual process in the field. Based on the implementation of improve geometry of hauling road overburden, it can increase the achievement of the productivity target by >700 bcm/hour, increase in the CpK value to 0.89 and Sigma Level to 3.37. Further improvement activities are still needed in accordance with the improvement scenario matrix of the 3 factors so that mining operations on soft materials can still achieve optimal and appropriate productivity.