Electroosmotic Drainage Applied to Mining Waste

Abstract

One factor affecting the stability of mining stockpiles is the moisture defined mainly by copper solution trapped in the porous by capillary. This moisture is not easy to remove if conventional methods are applied which use pressure or gravity as driving force. In the case of saturated or partially saturated soils with water, containing a large fraction of fine material, electroosmosis not only allows to reduce the humidity but also changes the structure, giving a higher strength and stability to the soils. Since the movement of the water, due to the electric gradient, is from the anode toward the cathode, the soil water content will decrease at the anode and will increase at the cathode. Water accumulated at the cathode then can be discharged by providing a drainage system at the cathode. This chapter presents theoretical and experimental aspects on electroosmotic drainage technique, based in works realized by the authors of this chapter. To explain the water flow through a mining residue containing a certain fraction of fine material and that in addition presents a high humidity, a model for the fluid flow in porous media is described here, taking into consideration two driving forces, defined by hydraulic and electric potentials.