Use of solid mining waste to improve water retention capacity of loamy soils

Abstract

Purpose. The research explores the possibility of increasing the fertile properties of agricultural soils of loamy type by adding burnt-out dump mass from coal enterprises. Methods. Laboratory research on parameters of penetration and retention capacity of sorbed and meniscal water for diffe-rent burnt-out rock fractions. The burnt-out rock was sampled from the mine No. 5/6 waste rock dump in the city of Myrnohrad, Donetsk Oblast, and divided into four fractions from 0.63 to 10 mm. The water penetration coefficient of the soil with the added dump mass is measured by the velocity of water seepage into the test samples. The ability of rock additives to retain film-sorbed and capillary water is assessed by comparing the weight of dry and moistened samples of crushed dump mass. Findings. The velocity parameters of water penetration into samples of loamy mixtures with burnt-out dump mass with fractions ranging from 10 to 0.63 mm in size have been determined. It has been found that an increase in the percentage of burnt-out rock in the mixture leads to an increase in the water penetration velocity from 1.2 ml/cm2·min with a rock content of 30% to 30.66 ml/cm2·min with a rock content of 70%. The highest penetration coefficients are achieved when adding rock with a small fractional composition of 0.63-3 mm, since an increase in grain size leads to a reduction in the coefficient by se-veral times. It has been determined that with an increase in the size of the rock fractions in a loamy mixture, the retention capacity of sorbed and pore water suitable for plant nutrition decreases by approximately 40%. Originality. For the first time, the parameters of penetration coefficients, as well as the accumulation of sorbed and meniscal water for mine waste in the Selidovo-Pokrovskyi district of Donbas, have been determined. Practical implications. The results obtained can be used to improve the physical properties of agricultural soils of loamy type by increasing their water retention capacity.