Simulation of Morphological Evolution near Sediment Mining Pits Using a 1-D Mixed-Regime Flow and Sediment Transport Model

In this study, a 1-D model has been applied to simulate the flow through an initially dry mining pit and the associated sediment transport and morphology changes. This model uses the generalized 1-D shallow water equations and non-equilibrium sediment transport equations, considering the interactions between flow, sediment transport, and bed change. The governing differential equations are solved using the finite volume method with an upwind scheme for the intercell fluxes and the scheme of Ying et al. for the water surface gradient term. This model is capable of handling the mixed-regime flows, so that the unsteady flow and sediment transport through the entire channel with a dry pit can be simulated. A total of 50 runs with varying pit lengths, pit depths, pit widths, channel slopes, unit flow discharges, and sediment sizes were simulated. The results from the 50 simulation runs were used to establish empirical envelope relations for the maximum headcut and tailcut depths and lengths. The established envelope relations can be used for channel stability analysis and mining pit design and management.