A Drainage Model for a Reclaimed Surface Mine1
- Lyle Prunty and
- Don Kirkham2
Stripmine reclamation for row-crop production employing bench-terraced geometry is under study and may become increasingly common. A simplified model of the postreclamation soil profile at the Iowa Coal Project Demonstration Mine No. I is created. The model is used to find the steady-state water-table shape if one tube drain per terrace is installed. Dupuit-Forchheimer (D. F.) theory is used for the analyses. Water-table curves are generated for a series of alternative drain-tube locations. An analysis is made to find the best position for the drain tube. It is found that, for a recharge-to-soil-conductivity ratio of 0.01 for terraces repeating at a 45.7-m (150-ft) interval, the best drain-tube location is beneath the horizontal portion of the terrace 4.87 m (16 ft) from the toe of the backslope if the drain tubes are placed 2.44 m (8 ft) beneath the surface of soil underlaid by a barrier at 3.05 m (10 ft) depth. The horizontal portion of the bench terraces is 38.08 m (125 ft), and the vertical drop from one terrace to the next is 3.05 m (10 ft). A table of best drain locations is given for other drain depths and recharge rates. Previous work on D.F. theory for a uniformly sloped barrier is discussed briefly and compared with and contrasted to the present work for a barrier that parallels the bench-terraced surface of the reclaimed surface mine.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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