Abstract. Based on the Regulation of the Minister of Environment and Forestry of the Republic of Indonesia Number 5 of 2022 concerning Wastewater Treatment for Mining Businesses and Activities, the resulting coal wastewater must meet the established standard quality standards it is necessary to treat wastewater so that it does not pollute the environment environment and interfere with human health. Management of acid mine drainage can be done by adding chemicals to neutralize the pH of acid mine drainage, one of which is by using fly ash. This research was conducted to determine the effectiveness of the use of fly ash in neutralizing the pH of the water and reducing the levels of Fe and Mn metals in the settling pond using several measurement and testing parameters, namely measuring the degree of acidity and testing the levels of Fe and Mn metals. The test results for 31 days showed that the average incoming water discharge was 614,462 l/day, the average pH value before handling was 5.64, the moderate Fe metal content before handling was 8.58 mg/l, and the average Mn content before handling of 5.60 mg/l. From the test results, it was found that the required amount of fly ash was 16,066 g/day. The effectiveness of increasing the average pH was 20.52%, the effectiveness of reducing Fe metal levels was 46.37%, and the effectiveness of reducing Mn levels was 40.99%. Abstrak. Berdasarkan Peraturan Menteri Lingkungan Hidup Dan Kehutanan Republik Indonesia Nomor 5 Tahun 2022 Tentang Pengolahan Air Limbah Bagi Usaha dan/atau Kegiatan Pertambangan bahwa air limbah batubara yang dihasilkan harus memenuhi nilai baku mutu standar yang sudah ditetapkan, maka perlu dilakukan pengolahan air limbah agar tidak mencemari lingkungan sekitar dan mengganggu kesehatan manusia. Pengolahan air asam tambang dapat dilakukan dengan menambahkan bahan kimia untuk menetralkan pH air asam tambang, salah satunya dengan menggunakan fly ash. Penelitian ini dilakukan untuk mengetahui efektivitas penggunaan fly ash dalam menetralkan pH air dan menurunkan kadar logam Fe dan Mn di settling pond dengan menggunakan beberapa parameter pengukuran dan pengujian, yaitu pengukuran derajat keasaman dan pengujian kadar logam Fe dan Mn. Hasil pengujian selama 31 hari didapatkan rata – rata debit air yang masuk sebesar 614.462 l/hari, rata – rata nilai pH sebelum penanganan sebesar 5,64, rata – rata kadar logam Fe sebelum penanganan sebesar 8,58 mg/l, dan rata – rata kadar logam Mn sebelum penanganan sebesar 5,60 mg/l. Dari hasil pengujian tersebut didapatkan jumlah kebutuhan fly ash sebesar 16.066 g/hari. Efektivitas kenaikan pH rata – rata sebesar 20,52%, efektivitas penurunan kadar logam Fe rata – rata sebesar 46,37%, dan efektivitas penurunan kadar logam Mn rata – rata sebesar 40,99%.