TECHNICAL STUDY OF OVERBURDEN EXCAVATION METHODS BASED ON MATERIAL CHARACTERISTICS AT PT KALTIM PRIMA COAL
Abstract
PT Kaltim Prima Coal is one of the largest companies in Indonesia engaged in coal mining. PT Kaltim Prima Coal aims to achieve an annual production target of 50.5 million tons of coal by 2024. To maintain a high production level, PT Kaltim Prima Coal must select the most appropriate and effective mining method to achieve fleet productivity. For this purpose, a technical study focused on selecting the most suitable overburden excavation method based on the characteristics of the overburden layers is required. The initial step to determine the most suitable method to apply is to use the Franklin Index diagram. Using the Franklin Index diagram requires testing the point load index of the overburden material at Pit X and directly measuring the fracture spacing (scanline fracture spacing) at the research site. Based on the analysis of data and technical studies conducted, overburden layers A, B, C, F, H, and I are recommended to use blasting methods for loosening, overburden layers D and E are recommended to use free excavation methods, and for overburden layers G, J, and K, it is recommended to use double blasting methods for loosening. Observations related to the productivity of excavator units at Pit X revealed an increase in productivity for each unit that initially used the free excavation method and was switched to the blasting method, ranging from 15% to 39% for the Liebherr R996, while a smaller increase occurred for the Hitachi EX3600-6B, which only saw a 3% increase in productivity.
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