Water dynamics of the 280 coal gangue dumps in Yangquan City

Shanxi Province was preliminarily studied by the analyses of physical properties

water infiltration characteristics

and water contentof the weathered gangue. Results showed thatcoal gangue texture was poor and the average contentof gravel and boulder was as high as 86. 07 %. The coal gangue dumps were dominated by non-capillary pore and the aver age values of capillary pore atthe four depths (15

30

45

and 60 cm) in the profile were 1. 40 %

1. 36 %

1. 32 %

and 1. 17 %

respectively. This caused soil water2holding capacity maintaining ata low-level throughoutthe year and the average water-holding capacity at60 cm depth was 19. 7 t/hm2. Kostiakov infil tration model can well describe the infiltration process of weathered gangue. During the infiltration process

weathered gangue had higher infiltration rate. The seasonal change in water contentof weathered gangue was mainly influenced by the amountof rainfall and its distribution. With the increasing seasonal rainfall

the av erage water contentof weathered gangue rose correspondingly. Water storage of gangue dump was linearly related with the amountof rainfall. When the amountof rainfall was low

or rainfall eventwas highly fre quent

water storage of exposed gangue was more than thatof the gangue dump covered with soil. Generally speaking

there was a dry layer between 30 and 40 cm in gangue dump

which made the lower layers of gangue dump keeping more moisture in dry season.