ANALYSIS OF ORE PILE STABILITY AT PT XYZ’S GOLD MINE HEAP LEACHING PAD USING FINITE ELEMENT METHOD

• Main Author: Nur Khodijah, Alfi
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/69352
• Institution: Institut Teknologi Bandung

PT XYZ is one of the gold mining companies located in Indonesia which utilizes the heap leaching method to extract gold from its ores. However, their ore pile at heap leaching pads was collapse starting from the 5th lift to the 7th. Water is suspected to be the primary cause of this ore pile collapse. In order to understand the cause of this collapse, a geotechnical analysis reffered the Decree of the Minister of Energy and Mineral Resources Number 1827/K/30/MEM/2018 was carried out. In this research, a slope stability analysis was executed utilizing the finite element method which employed Phase2 8.0. software subjected to the Mohr-Coulomb criterion. The safety factor (FK) value itself was approached by the values of strength reduction factor (SRF). The data used for analysis was secondary data obtained directly from PT XYZ and also from laboratory tests. The laboratory tests were the physical properties for determining the ore pile density value and the direct shear test for it’s internal friction angle and cohesion value. In the slope model, the water surface drawn horizontally and it’s pressure condition was assumed to be at maximum value or at hu=1 and the ore pile at heap leaching slope was composed by fresh ore, spent ore, and saturated spent ore. From the results of the analysis, it is obtained that the slope was in an unstable condition at the moment of the saturated spent ore water level reached a height above 10 m from toe. Therefore, it is necessary to provide some remedial actions, namely by placing the buttres or counterweights, instaling the horizontal drainages facilities, and monitoring the slope deformation.