An introduction to mine hydrogeology / Введение в шахтную гидрогеологию

Groundwater is one of the most important renewable resources of the Earth and it occurs in many sites. Water in the form of rainfall and river or stream water penetrates the ground and moves through the pores of soils, rocks, and rock fractures and joints which are permeable enough to transmit water through them. The Earth’s total water resources have been estimated to be of the order of 1.37 9 108 million ha-m. Out of these water resources, about 97.2 % is salt water, available only in the Oceans and only 2.8 % is available as fresh water at any given time on our planet. Out of these 2.8 about 2.2 % is found as surface water and rest only 0.6 % as ground water. It is interesting to note that out of 2.2 % surface water, 2.15 % fresh water locked in the glaciers and ice caps and only to the tune of 0.01 % (i.e. 1.36 9 104 M h am) is available in reservoirs and lakes and only 0.0001 % in streams, 0.001 % as water vapour in atmosphere and 0.002 % as soil moisture in the 0.6 m of top soil. Out of 0.6 % ground water which is stored in the sub surface, only about 50 % of it (i.e. 41.1 9 104 M ha-m) can be economically exploited which is occurring down to a depth of 800 m. Presently about one-fifth of all global water being used is groundwater (Raghunath 1982, 1987). <...>