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A Mechanical System for Soil Reconstruction

Fulton, J.P., Wells, L.G., Smith, T.D.
Applied engineering in agriculture 2002 v.18 no.5 pp. 517-524
earthmoving equipment, materials handling, mining, plant growth, rooting, scrapers, soil, soil compaction, traffic, trucks, Kentucky
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.