00323nam a2200121Ia 4500008004100000020001800041041000800059082001700067100001400084245005200098260004300150300000800193211209s1998    xx            000 0 und d  a81-224-0974-1  aeng  a622.322  SIN  aSINGH R D  aPRINCIPLES AND PRACTICES OF MODERN COAL MINING   aNEW DELHIbNEW AGE INTERNATIONALc1998  a696