ASSEMENT OF ENVRIONMENTAL STABILITY IN SEA WATER FOR THE BLOCK MADE BY COAL ASH MIXTURE

The assessment of environmental stability for the block made by coal ash mixture (ash block) is very important to conserve a marine ecosystem. In order to evaluate the environmental stability of the ash block, mineral composition, grain size analysis, evaluation of heavymetal pollution, source estimation of sediments, uniaxial compress test, weight change of ash block and reaction path modeling were investigated. Quartz and illite were most abundant mineral associated with plagioclase, halite, chlorite, smectite, and kaolinite. The mean grain size gradually increased toward surface and gradually decreased toward north. The sorting is classified poorly sorted or very poorly sorted and its skewness is classified coarse-skewed. The kurtosis increase at the coarse grained sediments. The concentration of heavy metal showed generally higher in northwestern part of study area and the distribution of heavymetal is affected by the grain size of sediments. The enrichment factor of heavy metals of sediments was lower than 1 except for Ni and Pb. The REE pattern indicates that all samples except for sample from 9 station are identical source. Moreover, Pair diagrams of Rb/Al vs. Ti/Al and Rb/Al vs. Nb/Al indicate that the source of upper sediments was very similar to source of lower sediments. The uniaxial compressive strength ranges 23 to 43MPa and its strength increase with increasing the deposition time in seawater. The weight change of ash block ranges -2.05 to 7.61% and the rate of change is insignificant. The ash block seems to be insoluble in ocean environment.