COMPARISSON BETWEEN 3D BLOCK MODELLING USING ORDINARY KRIGING AND 2D MODELLING USING POLYGONAL FOR ESTIMATING ALUVIAL TIN RESOURCES IN BANGKA ISLAND

• Main Author: Padmasari Anggraini (NIM : 12114031), Olga
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/29878
• Institution: Institut Teknologi Bandung

The alluvial tin ore deposit in Blok I, Blok II, and Blok III located in Northern, Central, and Southern parts of Bangka Island is one of a few abandoned people’s mine site, making the litology of this site dominated by tailings, a few remainders of alluvial tin deposit, and bedrock. This research is conducted to estimate the initial potential of alluvial tin resources based on drilling holes data, 54 points in Blok I, 68 points in Blok II, and 50 points in Blok III obtained from several different periods of exploration drillings which are, from 1970’s, 1980’s, and 2010’s for Blok I, 1980’s and 1990’s for Blok II, also 1960’s, 1970’s, 1980’s, and 1990’s for Blok III. Spatial and cummulative data distribution analysis is also conducted to determine the consistency between each period. The geological modelling was done utilizing Datamine Studio 3 software, and Ordinary Kriging method was used to estimate the tin grade of the deposit. The geometry of the three dimensional proto model applied is 10 m x 10 m x 1 m. In order to support the estimation dan simulation, a variogram analysis is performed to define the nugget variance, sill, and range parameters by fitting spherical model. According to the estimation results, the measured resources of aluvial tin deposit was 69700 m3 with average grade of 8 kg/m3 for Blok I, 81575 m3 with average grade of 8.87 kg/m3 for Blok II, and 87700 m3 with average grade of 13.29 kg/m3 for Blok III. In comparisson, resoureces modelling in 2D using Polygonal method utilizing AutoCAD 2019 (free trial), was estimated as measured resources of 96870 m3 with average grade of 13.61 kg/m3 for Blok I, 106348 m3 with average grade of 14.74 kg/m3 for Blok II, dan 109735 m3 with average grade of 14.86 kg/m3 for Blok III.