Potential Analysis of Ex-Coal Mining Land As Pumped Storage Hydro Powerplant In Kutai Kartanegara, East KalimantanYollanda Z. Devi, Andang W. Harto, Rachmawan Budiarto and Novi TrihastutiE3S Web Conf., 42 (2018) 01009DOI: https://doi.org/10.1051/e3sconf/20184201009