Sensitivity Analysis of Net Present Value due to Optimal Pit Limit in PT Ceria Nugraha Indotama, Kolaka Regency, Southeast Sulawesi Province

Abstract

PT Ceria Nugraha Indotama is planning to open a new mining site in Lapaopao Block area. In order to determine the most profitable pit design on this new area, pit limit optimization is required. Pit limit is optimized by considering economic parameters, geotechnical parameters, and production target. The optimal pit limit generates the highest Net Present Value (NPV) which is affected by economic parameters. The objective of this research is to analyse the NPV sensitivity of pit due to the changes of economic parameters namely mining cost, processing cost, and selling cost by using sensitivity analysis. Data used in this research were drill hole, ore and waste density, slope geometry, production target. The planned production target, ore price, recovery factor, dilution factor, mining cost, processing cost, and selling cost. The analysis results showed when mining costs increased by 20%, NPV decreased from $2,407,032 to $1,683,430 and when mining costs decreased by 20%, NPV increased from $2,407,032 to $3,130,635. When processing cost increased by 20%, NPV decreased from $2,407,032 to $2,133,523 and when processing cost decreased by 20%, NPV increased from $2,407,032 to $2,680,542. When selling cost increased by 20%, NPV decreased from $2,407,032 to $1,995,755 and when selling cost decreased by 20%, NPV increased from $2,407,032 to $2,818,310. It indicated that the economic parameters significantly affect the NPV and most sensitive to the mining cost parameter changes.