Accuracy of Self-Heating Modeling in Coal Stockpiles in the Warukin Formation, South Kalimantan, Indonesia

The study aims to improve the accuracy of self-heating prediction of lignite-A coal from the Warukin Formation by comparing modeling and actual temperature measurements. Modeling with COMSOL Multiphysics® predicts the temperature on day 30 of 468 K, while the actual temperature is 507.65 K. The modeling equation (Tpred) is 1.33 times time and added 412.50, while the actual equation (Tobs) is 2.16 times time and added 441.07. The high correlation coefficient (r) is 0.95, the Mean Absolute Error is 16.81 K, and the Root Mean Square Error is 20.48 K. The average relative error of the model is 0.01, indicating an effective model. This study discusses the importance of monitoring and control strategies in monitoring lignite-A coal stockpiles to reduce self-heating risk.