PIT Design And Sequencing Pit Mine Of Coal Mining At PT Lithoindo Job Site PT Trimata Benua Tungkal Ilir Sub-District, Banyuasin District Sumatera Selatan Province

Abstract

PT Trimata Benua is one of mining company who has IPP permission as coal supply which will be used for PLTU at Sumatera Selatan Province. So, it is need a good mine planning in order to achieve optimal production target. Pit design in mining block 1 and 2 is done by using computer software from coal resources to be mined. Then, optimal design results obtained in the area of coal potential in the mining block. Measured resources obtained from the results of computer model of 97.155/274,78 tons. The parameters needed to pit design in both blocks, including: mine slope geometry, boundary mining (pit limit), and economic stripping ratio. Based on calculating of BESR II (Break Even Stripping Ratio) and Economic Stripping Ratio obtained limit the economic potential stripping ratio is 5,6: 1. Thus, the final design Pit 1 and 2 with a maximal total depth of 80 meters with Pit 1 overall width is 146,6 Ha and Pit 2 overall width is 96,7 Ha, obtained each Stripping ratio is 4,02 and 5,39. Based on design optimization, obtained mineable reserves on Pit 1 is 38.951.842 tons with overburden volume is 156.803.658,6 BCM. And on Pit 2 is 9.375.392 tons with overburden volume is 57.918.909,97 BCM. Annual production target of PT Trimata Benua is 3.500.000 tons/year, The first year's production plan until the year to 13 is 3.500.000 tons of coal, and the eighth month in the year to 13 is 2.827.234 tons of coal, thus obtained life of mine is over 13,8 years. The quality of coal in the production activity in pit 1 year 1 and 4 based on the profile of coal quality at the point of the drill SMGC-18 and SMGC-09 will find the value of ash content dominant high in value is 20.72% the mining depth of 10.8 m - 13.6 m and 24 m - 28.1 m. Futhermore, the quality of coal with water content and high volatile matter was found in year 4 and 10 on the mining depth of 42.6 m - 47.1 m. Meanwhile, the pit 2 will find the value of ash content and a high water content in the year to 12 at a depth of mining 48 m - 53 m with their respective values of 10.33% and 40.7%.