508 the copper concentrate grade exceeds 20% Cu, concentrate from the first cell of the bulk cleaner circuit is bypassed to the final product stream. The remaining bulk cleaner cells' concentrates are sent to a bulk concentrate thickener, then to the regrind circuit, and finally cleaned in the cleaner circuit to produce the final concentrate. Figure 25 shows a simplified flowsheet of the Toromocho circuit Figure 25 – Toromocho Simplified Comminution and Flotation Circuit Flowsheet (Phase I and Phase II) Toromocho commenced operations in 2013 (with Phase I) and was designed to process a nominal throughput of 5,250 tph. However, the ore hardness values used for plant design are significantly softer than those encountered during operation. This resulted in higher specific energy consumption, negatively impacting plant throughput and preventing the operation from reaching its design capacity. In response to the higher specific energy consumption, Toromocho adopted a proactive improvement strategy rather than accepting the limitations imposed by the original design. Feed size has a significant impact on the performance and capacity of comminution circuits. Therefore, the initial focus was drill and blast optimization tailored to feed ore characteristics (rock structure and strength) to produce finer ROM fragmentation and, consequently, a finer SAG mill feed. This was followed by the extension of optimization efforts downstream to ensure that the comminution circuit could fully capture the benefits of the improved feed size distribution. The structured drill and blast optimization program was developed and implemented at Toromocho in 2017. Key ROM fragmentation indicators including P80 and fines content (% passing 1 inch and % passing ½ inch) and show sustained improvement over time. The ROM P80 has reduced and fines content increased. These upstream improvements provided the foundation for a broader, integrated optimization effort across the concentrator. Building on this progress, the structured Mine-to-Process program progressed to optimization of comminution and flotation, supported by detailed surveys, ore characterization, modelling, simulation and throughput forecasting. Opportunities were identified to increase the total grinding throughput (from both grinding lines) by up to 14% but with some coarsening of the target product size. Integrated simulations across comminution and flotation indicated the increase in throughput and coarser grinding product size would, for a fixed concentrate grade, reduce overall copper recovery by ~1% if downstream constraints were not addressed. However, flotation debottlenecking and optimization identified quick-win and major CAPEX opportunities. Simulations indicate that the quick-win measures may improve overall copper recovery by ~1.5% while maintaining concentrate grade, with further gains possible via major CAPEX initiatives. Subsequent implementation of the quick-win initiatives has demonstrated the expected benefits. A summary of key activities and events is provided below: • In 2021, a significant increase in throughput (~10% increase compared to 2020) was achieved for the Phase I grinding line following the optimization study carried out in 2020.
RkJQdWJsaXNoZXIy MTM0Mzk2