ANALYSIS OF RELATIONSHIP BETWEEN VARIOGRAPHY AND SPACING OF EXPLORATION DATA OF LATERITIC NICKEL DEPOSIT IN GEE AND PAKAL ISLAND EAST HALMAHERA

• Main Author: RUSTIAWAN (NIM 12103061), WAWAN
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/11578
• Institution: Institut Teknologi Bandung

Gee and Pakal Island are the area of mining contract which belong to PT. ANTAM, Tbk, where located in East Halmahera, North Maluku Province. Gee Island has been mined and it is supposed having the same characteristic of deposits with Pakal Island. At this time in the Pakal Island is conducted the semidetail and detail exploration of lateritic nickel deposit. To get the more optimum model of sampling, it needs done the variography analysis that is related to the spacing of exploration data.<p>The methodology of research are study of literature and collection of assay data from PT. ANTAM, Tbk. In this research, the the assay data is divided into limonite zone, Low Saprolite Ore Zone (LSOZ), and High Saprolite Ore Zone (HSOZ). From the assay data can made the descriptive statistic and variogram models. The variogram is made by four main direction on three kind of different spacing of data, i.e. 100 m, 50 m, and 25 m.<p>Based on variogram analysis, the nugget effect will increase if the spacing of data is closer. This indication is shown from the comparison of different nugget effect from different spacing of exploration data, for the same variable. The one of example that explain this indication is the comparison of nugget effect of Fe grade in LSOZ zone, in Pakal Island, where the nugget effect from the spacing 100 m, 50 m, 25 m are 5, 10, 40 respectively.<p>The other result of variogram analysis is the range value between 40-50 m is nearly to be an optimum range. This result is obtained by comparison the different range for the same variable, in the different spacing of exploration data. The indication is the range will decrease if the spacing of exploration data is closer. The one of example that explain the indication is the comparison of range of Ni grade in HSOZ zone, in Gee Island, where the nugget effect from the spacing 100 m, 50 m, 25 m are 200, 85, 60 respectively.