Modelling Hydrological Performance of a Bauxite Residue Profile for Deposition Management of a Storage Facility

Abstract

Accurate scheduling of bauxite residue (red mud) deposition time is required in order to prevent the risk of storage facility failure. This study was conducted to precisely determine the hydraulic parameters of bauxite residue and investigate the capability of HYDRUS to accurately estimate the residue moisture profile and the timing for its deposition. The hydraulic properties of the bauxite residue profile were determined by solving an inverse problem. A one-dimensional hydrological model (HYDRUS-1D) was validated using a 300 mm long column filled with bauxite residue and exposed to a dynamic lower boundary condition. After numerical validation, the model was used to simulate the moisture profile of bauxite residue under the climatic conditions of an alumina refinery site in Queensland, Australia, as well as other scenarios (i.e., high (300 mm) and small (1.7 mm) rainfall events of the site). This study showed that the HYDRUS model can be used as a predictive tool to precisely estimate the moisture profile of the bauxite residue and that the timing for the re-deposition of the bauxite residue can be estimated by understanding the moisture profile and desired shear strength of the residue. This study revealed that the examined bauxite residue approaches field capacity (water potential −10 kPa) after three days from a low rainfall event (<1.7 mm) and after eight days from an intense rainfall event (300 mm) at the time of disposal. This suggests that the bauxite residue can be deposited every four days after low rainfall events (as low as 1.7 mm) and every nine days after high rainfall events (as high as 300 mm) at the time of deposition, if bauxite residue experiences an initial drying period following deposition.

Improving Soil Stability with Alum Sludge: An AI-Enabled Approach for Accurate Prediction of California Bearing Ratio

“…Various functions are provided for this purpose. Some of these functions, including linear, nonlinear, polynomial, radial basis function (RBF), and sigmoid, are given in Equations ( 1)- (5). According to Equations ( 1)-( 5), the kernel function is a series of mathematical functions that provide a window for data manipulation.…”

“…As a result of this reaction, soil density and compaction increase, improving soil stability and reducing erosion sensitivity [4]. In addition, for pure aluminum sludge, the stability gained by adapted scheduling of bauxite tailings, is critical to warrant safe tailings deposition [5].…”

Reclamation of Salt-Affected Land: A Review

“…Once a validated model has been confirmed and experimentally validated, any scenarios can be simulated by the model to predict the outcome of reclamation strategies. The same modelling approach can be applied to any porous media from non-soil like substrates as can be found in mining such as tailings [168,169] and rocky and gravelly materials [170][171][172] to evaluate different scenarios on their management strategies.…”

Multi-Year Mapping of Disturbance and Reclamation Patterns over Tronox’s Hillendale Mine, South Africa with DBEST and Google Earth Engine

“…We further inspected the site-specific pixel trajectories for three sites within the operational area, and the outcome is presented in Figure 7. Site A represents the RSF-an earth-fill embankment facility formed by the disposal of residuals after extraction and beneficiation of the minerals [63], and is characterized by very fine-textured material and very high salinity, resulting in a much-reduced drainage capacity and leading to prolonged times for drying and stabilizing the substrate [64], as illustrated in Figure 8. As expected, lower NDVI values (~0.1) are apparent throughout the course of the mining operation until a marked increase in 2013 when the rehabilitation began.…”