Soil Mechanics Investigation for the MOPH-I and MOPH-II Plants – SQM, Salar de Atacama

Project Period: June 2023

Project Overview

Pangea Geotechnia carried out a comprehensive geotechnical site investigation for the expansion of **SQM’s MOPH-I and MOPH-II plants** in the **Salar de Atacama**. The investigation included **eleven 25-meter boreholes** with geochemical sampling, geophysical surveys, and additional **high-resolution in situ pressuremeter testing** to determine key geotechnical parameters. The results provided essential information for the foundation design, taking into account the unique geological and geotechnical conditions of the site. The investigation identified underground cavities at various depths, likely associated with both natural mineral dissolution processes and mining-related activities. These findings had a significant influence on the foundation design recommendations, leading to the proposal of a **raft foundation supported by micropiles** to mitigate the effects of the subsurface voids. The study also included detailed recommendations regarding the design, capacity, and performance of the micropiles, together with guidance for alternative foundation solutions without micropiles, including ground improvement strategies. This geotechnical investigation provided critical engineering information to support the structural integrity of the expansion of SQM’s MOPH facilities. By thoroughly assessing the site conditions and addressing the challenges posed by underground cavities and the unique geotechnical characteristics of the Salar de Atacama, the study established a sound basis for the safe and reliable construction of the project.