A large‐scale laboratory infiltrometer system was used to determine infiltration characteristics of “reconstructed” surface mine spoil and soil horizons. Soil water characteristic curves were determined using the Brooks‐Corey and the Gardner procedures and developed based on desorption tensiometer data. Unsaturated hydraulic conductivity values were determined using the “plane of zero flux” procedure and compared with predictions resulting from models described by Campbell, Burdine, and Mualem for situations involving reconstructed soil and spoil materials. There was generally good agreement between the models and excellent agreement between Campbell's predictions and plane of zero flux results. Both the Gardner equation and the Brooks‐Corey equation gave good estimates of the soil water characteristic curves for the materials. The physical significance of the parameters θr and ψe, when determined by statistical procedures, appears very questionable. In this study, the final steady‐state infiltration rate appeared to be a good estimate of the hydraulic conductivity at apparent saturation.

One of the most perplexing problems associated with reclaiming surface-mined lands is excessive compaction of soil due to the heavy earthmoving equipment used during the reclamation process. Over the years, some innovative material handling schemes have been devised to limit vehicle traffic during reclamation on reconstructed soil. However, final grading operations can often create root-limiting bulk densities, which affect plant growth and yield. The purpose of this article is to describe a mechanism designed at the University of Kentucky whereby mine soil can be reconstructed without introducing compaction caused by surface traffic in order for the soil to sustain desirable plant life. The soil handling process for this prototype mechanism is also described. The prototype soil forming mechanism is mounted on the front of a conventional bulldozer. Soil and other rooting media are placed atop graded spoil in long, narrow windrows by scrapers or trucks. As the bulldozer pushes its blade into the windrow, material rises up onto the blade and an auger grinds and displaces soil perpendicular to the direction of dozer travel. The agitated soil is then deposited and leveled in an adjacent berm by the auger. Successive parallel passes of the mechanism results in the construction of a non-compacted rooting layer. Preliminary testing of the prototype yielded a soil construction rate of 330 m 3 /h (430 yd 3 /h), which was 12% of the projected theoretical design capacity [2680 m 3 /h (3500 yd 3 /h)]. Though the measured capacity is much lower than anticipated, it is believed the actual capacity of the prototype can be increased to 900 m 3 /h (1177 yd 3 /h) which would be an acceptable soil forming capacity at most mine sites.

Click here to let us know how access to this document benefits you.ABSTRACT E XPERIMENTS were conducted on large field cores to determine the relationship between drainage volume and water table depth for five soils. The measured drainage volumes were less than predicted from the soil water characteristics for three soils, but were in good agreement for the other two. Drainable porosities were calculated from both theoretical and experimental drainage volume-water table depth relationships by assuming that the unsaturated zone is essentially 'drained to equilibrium , with the water table. The experimental drainable porosities thus obtained were less than predicted.Drainable porosities for drainage in two-dimensions were calculated from experimental results for onedimension by assuming an elliptical water table profile. These results gave nearly constant drainable porosities for the layered soils and a variable drainable porosity for Wagram, a homogeneous, sandy soil.

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