U. Buczko et al., Spatial distributions of lignite mine spoil properties for simulating 2-D variably saturated flow and transport, ECOL ENG, 17(2-3), 2001, pp. 103-114
In open-cast brown coal mine spoils, the effect of heterogeneity on water h
ow and solute transport is largely unknown. The objective of this study is
to analyze tile effects of differently generated hydraulic property distrib
utions on transport processes in mine spoil heaps originating from open-cas
t lignite mining. Spatial distributions of hydraulic properties are generat
ed with two different approaches. A deterministic approach is based on the
description of mixing, segregation, and compaction during dumping. Using in
formation on the mining and dumping technology along with geological proper
ties of overburden sediments, we generate spatial distributions of the spoi
l bulk density and texture for a representative 2-D-vertical cross-section
of 22 m depth and 29 m width. Water retention is calculated with the Arya a
nd Paris approach and hydraulic conductivity with the Kozeny-Carman equatio
n. The second approach uses direct geostatistical simulation of relative hy
draulic conductivity. Water flow and solute transport is simulated with the
numerical finite element code SWMS_2 D. The deterministic approach leads t
o a two-peaked concentration front with tailing. A significant fraction of
the solutes is transported faster as compared with a homogeneous profile. B
oth approaches induce a spreading of the concentration front. Utilizing ava
ilable information on the dumping technology and on the overburden geology
may help to improve predictions of water flow and solute transport in spoil
heaps. (C) 2001 Elsevier Science B.V. All rights reserved.