摘要
I.IntroductionIt is common practice to dump the largequantity of fly ash collected from the burn-ing of pulverized coal in coal-fired thermal powerstations in ash dumping yards constructed overlow-lying land or in the mountain valleys,whichnot only occupies large areas of land,but is alsoa public nuisance when the dried fly ash is blownup by wind.In the past it was advocated to coverthe ash dump with a layer of soil to prevent theash from being stirred up and also to grow cropson the soil-covered fly ash.Success to someextent has been claimed.However,to cover thelarge areas of ash dump requires considerablequantity of soil:to surface an ash dump of 100hectares with a thickness of only 0.2m willrequire 200,000m^3 of soil.Under the
