Analisis Kestabilan Lereng Menggunakan Metode Kesetimbangan Batas pada Lereng Low Wall Pit "B" di Kawasan Pertambangan Batubara, Kabupaten Tapin, Provinsi Kalimantan Selatan = Slope Stability Analysis Using Limit Equilibrium Method on Low Wall Pit "B" Slope in Coal Mining Area, Tapin Regency, South Kalimantan Province