PREDICTION OF WATER QUALITY IN THE PIT LAKE AT COPPER-GOLD MINE WITH PHREEQC SIMULATION

• Main Author: Nafisah Agustya, Tsara
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/86361
• Institution: Institut Teknologi Bandung

Mining activities, especially those carried out in open-pit operations, often leave complex environmental impacts, including the formation of pit lake. Pit lake is created from former mining pits that become filled with water after mining activities have ceased. The water quality in pit lake is often affected by remaining from the mining process, such as acid mine drainage. Copper-gold mines also have the potential to generate acid mine drainage. Therefore, research on predicting water quality in pit lake is essential. Water quality prediction is conducted using PHREEQC through inverse modeling, forward modeling, and mixing simulations. The components required for prediction include rainwater quality, field column test data, pit wall rock mineralogy, and the surface area of pit wall rock. Based on research, it was found that the reaction rate of acid mine drainage formation in the leach column varies according to the mole transfer values. At low pH levels, sulfide-containing minerals tend to undergo greater mole transfer than other minerals, indicating that the acid mine drainage formation process occurs rapidly. Furthermore, the simulation results show that the acid mine drainage formation reaction involves three main components: sulfide minerals, oxygen, and water. According to the water quality prediction simulation, the final pH value is expected to be 3.48, which is still classified as acidic. Additionally, considering other elements present in the initial column leaching test, the final predicted pH is 3.65, which remains acidic. The presence of additional elements slightly raises the pH, suggesting that there may be other sulfide minerals not detected by the software simulation.