Model Keberlanjutan Lingkungan Pertambangan Batubara (Kajian Nilai Jasa Lingkungan, dan Air Void Tambang sebagai Air Baku di PT Bukit Asam Tbk Tanjung Enim Sumatera Selatan) = Environmental Sustainability Model for Coal Mining (Value Assessment Environmental Services, and Mining Void Water for Raw Water of Coal Mining PT. Bukit Asam, Tbk, at Tanjung Enim, Sumatera Selatan)