GRADE-CONTROL STUDY OF THE BIG GOSSAN UNDERGROUND MINE, PT FREEPORT INDONESIA, PAPUA

• Main Author: Sedik, Manfret
• Format: Final Project
• Language: Indonesia
• Subjects: Pertambangan dan operasi berkaitan
• Online Access: https://digilib.itb.ac.id/gdl/view/37280
• Institution: Institut Teknologi Bandung

Grade-control practice in a mining operation is essential to the balanced evaluation of resources and reserves. It involves comparing the data taken from the exploration drill-hole dataset with data taken from the grade-control drill-hole dataset obtained during the mining operation. The Big Gossan underground mine of PT Freeport Indonesia (PTFI), Papua was chosen for this case study due to the availability of data and the grade-control activities carried out there. The two data sources used in this research included exploration drilling data and grade-control drilling data obtained by PTFI’s Big Gossan Underground Geology Department. The drill-hole data were used in modeling for constructing 3D visual models, for geological interpretation, and for grade-tonnage estimation. The general methodology included string, triangulation, and wireframe building in order to create a formation model for both exploration drilling data and grade-control drilling data. Next, the mineralization domains defined by equivalent Cu 1% were determined for both data sources. The result of the mineralization domains are as follows: Tersier Waripi Mineralization, Tersier Waripi Non-Mineralization, Kemblangan Ekmai Mineralization, and Kemblangan Ekmai Non-Mineralization. Geostatistical analysis for each domain was conducted in order to create and estimate the block models. The result indicates a difference in metal content between the exploration data and the grade-control data, which may be described as follows: The average Cu content for the exploration data and the grade-control data was 0.503% and 1.204%, respectively; the average Au content for the exploration data and the grade-control data was 0.554% and 0.258%, respectively; and the average Ag content for the exploration data and the grade-control data was 10.432% and 6.450%, respectively.