摘要：Tissue Preservation Index (TPI) and Gelification Index (GI) are products in coal related to the quality of coal and acid water mining. Research is conducted to know the relationship between the two by means of correlation using polynomial method and pressing method on the environmental diagram of the depositional environtment/facies. The correlation result is obtained that the higher the value of TPI, the value of Inherent Moisture and Volatile Matter is lower and the value of ash content and Fixed Carbon is higher. The higher the value of the GI, then the value of ash content and Fixed Carbon is higher and the value of Volatile Matter is getting lower. The lymnic deposition facies are areas that are located far from the sea and covered by a barrier and composed of land sediment with an active hydrological system. This is what causes minimal acidic water to occur because the sea sulfide does not intervene in the surrounding rocks. In addition, high GI value levels in the research area cause the oxidation process to be low and result in low rock acidity conditions.
