Optimasi Perencaanaan Tambang Terbuka Nikel Laterit Menggunakan Pendekatan Hill of Value

Abstract

This research aims to optimize the design of a lateritic nickel open-pit mine by applying the Hill of Value (HoV) method to determine the Ultimate Pit Limit (UPL). Conducted at PT XYZ in East Luwu Regency, South Sulawesi, the study focuses on analyzing the impact of key economic and operational parameters on project viability. The research employs a quantitative approach, utilizing secondary data including topography, borehole data (collar, survey, assay), and financial parameters (capital cost, operating cost, selling price). Data processing involves block modeling and multi-scenario economic simulations that vary cut-off grade (COG), production rate, and nickel price. The results are visualized using threedimensional and contour HoV graphs to identify optimal parameter combinations.The findings indicate that: (1) Variations in COG and production rate significantly impact economic feasibility and total mineable ore reserves, with optimal economic value generally found at a COG of 0.75–1.00% and a production rate of around 1 million tons/year. (2) The combination of a nickel price ≥ 70 USD/ton and a production rate of 1.0–1.3 million tons/year yields the highest Net Present Value (NPV) zone, whereas low prices combined with high production rates increase the risk of financial loss. (3) The recommended optimization strategy for determining UPL involves increasing the COG to the range of 1.0–1.5% and reducing the production rate to approximately 600,000 tons/year, which represents the highest peak in the Hill of Value analysis, maximizing NPV while ensuring operational efficiency. This study concludes that the Hill of Value method provides a more adaptive and comprehensive framework for mine design optimization compared to conventional deterministic approaches. It effectively captures the complex, non-linear interactions between economic and technical parameters, enabling the identification of an optimal UPL that balances economic value with reserve utilization under conditions of price uncertainty