“Pengaruh Mineral Sekunder Sulfat Hasil Oksidasi Pirit Terhadap Nilai Total Sulfur Pada Batubara Formasi Haloq dan Serpih Karbonan Formasi Batuayau Cekungan Kutai Atas: Effect of Secondary Sulphate Mineral theresults of Oxidation Pyrite againt Value Total Sulfur In Coal Formation Haloq and carbonaceous shale Formation Batuayau On the Kutai Basin” (2018) PROMINE, 4(2). doi:10.33019/promine.v4i2.108.