Modification RCA N ° 227/2011 Flotation of Slag Potrerillos

Description: Currently, as part of the operation of the Potrerillos Foundry, the high grade copper slag (Cu) generated in the fusion process that is carried out in the Teniente Converter, is processed in a Slag Flotation Plant (PFE), obtaining a low sulfur concentrate as a product, which is recirculated to the smelter, and a tailings slag that is deposited in a filtrate tailings deposit (DRF). Both the Slag Flotation Plant and the current Filtered Tailings Depository are evaluated and environmentally approved through the Environmental Qualification Resolution No. 227/2011 issued by the Environmental Assessment Service of the Atacama Region. The Slag Flotation Plant has a design capacity of 1,700 tons / day, currently processing 1,530 tons / day of slag. The current deposit of slag tailings, which is part of the project approved by RCA N ° 227/2011, has a limited disposal capacity, which makes it necessary to have a new tailings deposit that allows the continuity of the disposal of filtered tailings from the Flotation Plant. For this purpose, the construction and operation of the "No. 2 Filtered Tailings Reservoir" has been projected, which will have a storage capacity of 2.8 million tons of filtered tailings, equivalent to approximately 5 years of deposit, which will allow the continuity of storage of filtered tailings generated by the Slag Flotation Plant, extensible according to the Salvador Division development plan, for approximate nominal tailings production of 1,500 tons / day, which is the expected rate for a PFE processing rhythm at 1700 tpd. Given the above, it also allows the extension of the useful life of the Slag Flotation Plant contained in the RCA N ° 227/2011. The tailings generated by the Slag Flotation Plant, which contain an estimated humidity percentage between 11% and 12%, will be deposited in the same way as in the current tailings deposit, that is, loaded on trucks and transported. to the Filled Tailings Tank No. 2 (see Figure 2-1). It should be noted that the tailings transport and operation activity of the current and future deposit will be developed during the day. The No. 2 Filtered Tailings Reservoir will conform to a standing wall of granular material that serves as support for the first layers of tailings to be deposited during the operation. The tailings disposal in the No. 2 Filtered Tailings Depository will be done by platforms, completing a total of 6 sequentially, which will be formed as, the tailings are discharged from the trucks that will transport them from the Flotation Plant of slag, and is arranged with the use of motor grader in horizontal layers approximately 30 cm thick, being compacted until reaching the density of compaction equivalent to 95% of the standard Proctor test. The tailings disposal in the No. 2 Filtered Tailings Depository, in each of the 6 platforms, will be materialized with an outer slope of 2.5: 1 (H, V) up to a stage height of 10 m per platform and between them , a traffic and safety berm of 3 m is contemplated, as shown in Map H355847-P112-220-260-0001, attached in Annex 2 of this DIA. The projected slope and the berms considered together with the density of compaction, ensure the static, pseudostatic and dynamic stability of the Deposit with safety factors higher than those required by the authority for the maximum estimated earthquake in the Project area. Between berms and as part of the operation, coverage is contemplated with granular material approximately 50 cm thick to the exposed surface of each completed platform, that is, this coverage will be available on the horizontal layer of the berm and on the outer slope that are exposed on each platform. The last platform will be completely covered with this coverage. The origin of the material that will be emp