867 3. METHODOLOGY The methodology considers the implementation of an online measurement system based on LIBS (Laser-Induced Breakdown Spectroscopy) technology on the Overland conveyor of Chuquicamata Underground, at a strategic point prior to the entry of the ore into the plant feeding system. This location allows for a representative capture of the variability of the material delivered to the process, before it is blended within the storage and distribution system. The system enables continuous measurement of the elemental composition of the ore (Cu, Mo, Fe, and As), transforming the traditional discrete sampling approach into a continuous, real-time monitoring scheme. 3.1 Measurement Principles LIBS technology is based on the generation of a plasma induced by a high-energy laser pulse on the surface of the moving material. This plasma emits characteristic radiation for each element present, which is captured and analyzed using a spectrometer. From this spectral signal, it is possible to estimate elemental concentrations of the ore in real time, with high sampling frequency, allowing continuous characterization of material variability. Unlike conventional sampling, which is based on discrete campaigns with frequencies on the order of days, LIBS technology enables real-time data acquisition with measurement frequencies of approximately 1000 Hz (1000 pulses per second). This high temporal resolution allows capturing short-term variability of the transported material, providing a more representative characterization of the grades delivered to the process and a better understanding of ore dynamics within the operation. 3.2 Calibration Strategy The initial stage includes system calibration under controlled conditions, using representative ore samples previously analyzed in the laboratory. For this purpose, approximately one tonne of representative material from Chuquicamata Underground was collected, covering the full range of expected concentrations of Cu, Mo, Fe, and As. The sampling campaign included the selection of 50 extraction points, from which approximately 20 kg of material was collected per point, following a prior assessment of grade representativeness. These samples cover the expected range of elemental concentrations, enabling the development of calibration curves, the establishment of relationships between spectral intensity and concentration, and the evaluation of repeatability, accuracy, and detection limits. This phase corresponds to factory validation, where the analytical performance of the system is verified prior to field installation. 3.3 Field Integration and Operational Implementation During the commissioning stage, the LIBS system is integrated into the plant operational control platforms (PI System), enabling real-time visualization and use of grade information under operating conditions. In this phase, tests are conducted with operating material, together with validations in controlled environments such as pilot plant conditions, to ensure that detection limits, accuracy, and sensitivity are representative and suitable for the characteristics of Chuquicamata Underground ore. System integration allows continuous grade measurement to be incorporated as a key operational variable, enabling its direct use in decision-making. In particular, real-time data supports the optimization of reagent dosing, improved control of feed quality, and increased metallurgical stability of the process. This approach supports the transition toward a data-driven operational model, reducing uncertainty in grade estimation and strengthening mine–plant reconciliation through improved traceability and representativeness of information.
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