INCREASING THE STATUS OF FORMER INLAND ALLUVIAL RESERVES INTO RESERVES BY BOREHOLE MINING AND GEOSTATISTIC EVALUATION OF THE REST OF TIN PROCESSING TO BECOME A RESOURCE, CASE STUDY: BANGKA-BELITUNG REGION

• Main Author: Azwardi, Ichwan
• Format: Dissertations
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/68609
• Institution: Institut Teknologi Bandung

The emergence and increasing prevalence of tin mining carried out by the community has an impact on the destruction of alluvial tin resources and reserves in the area of IUP PT. Timah Tbk. leaving former of reserves. The former reserves that are scattered in local forms can no longer be mined using the spray mining method because of their dimensions and economic factors. This condition causes these former reserves to be reclassified as resources and causes the amount of tin reserves to decrease. When there is a significant decrease in production from PT. Timah Tbk. during the period 2011 – 2016, various programs were implemented including by accommodating tin ore from the remaining processing results (SHP) by the community, so that in the 2017-2019 period PT. Timah Tbk has succeeded in increasing its tin production again. The company's success to increase its production again raises new problems, because on the tin balance, there is an imbalance between the amount of production and the amount of tin resources and reserves which is officially declared by the company based on the resource and reserve reporting standard (JORC/KCMI), especially in 2019. In 2019 tin production from onshore production experienced a very significant increase and exceeded the amount of tin reserves in the same year. The focus of this research is to analyze in detail the causes of the existing problems, then find and propose solutions so that the tin balance can be adjusted. The main research objects that will be examined are the former alluvial tin reserves which are scattered locally in irregular shapes and the condition of the residual processing results (SHP) which are indicated to be the cause of the discrepancy in the tin balance. The modifying factor that will be used to change the classification of former onshore alluvial tin reserves from resources to reserves is the spraysuction borehole mining method, which is one of the novelties in this research. As for the SHP, a quality test will be carried out by taking samples at several SHP locations and then doing a geostatistical analysis to produce a classification range for the confidence level of SHP deposits which is also a novelty in this study. The main objective of this research is to produce a modifier factor to improve the classification of scattered alluvial tin reserves into recovered reserves and state that SHP deposits can still be classified as resources. The results of this study indicate that spray-suction borehole mining can be applied to mining in former onshore alluvial tin reserves so that it can be a factor for converting resources into reserves. This study also proves that the SHP sediment has a sediment confidence level classification so that it can be stated as a resource.