Environmental Management
Pit Lakes
Numerical Modeling
Project Permitting

Mine operations may include the discharge of finely ground waste rock to lakes, coastal ocean waters, or shallow freshwater ponds where they are transported by currents, deposited on the bottom, or resuspended by waves or currents. To better assess the resulting environmental impact Lorax uses a variety of numerical models to simulate the fate of these sediments. These include models for:
  • Surface wave-induced sediment re-suspension
  • Three-dimensional hydrodynamics; including wind- and tide-driven currents, as appropriate, to provide currents to a sediment transport and dispersion model (STD Model).
  • STD Model for determining the concentration of total suspended solids (TSS) and sediment deposit thickness.

Surface waves can be an important cause of re-suspension in shallow ponds. Lorax has developed a parametric model that uses wind speed and direction data together with detailed bathymetry to calculate the stress acting on the bottom from surface waves. With an understanding of the sediment properties it is possible to estimate the resulting rate of re-suspension.

Lorax utilizes both the Princeton Ocean Model (POM) and a proprietary model, C3, to generate three-dimensional current fields for oceans and lakes that can be used by a STD model. Sediment transport is simulated by the STD model by using hundreds of thousands of pseudo-particles to represent actual sediment mass. The particles are moved in three-dimensions by currents provided from a hydrodynamic model or from current measurements, and settle to the bottom at a rate that depends on their diameter and density.