Written by Chuck Wanstrom
The Aripuanã mine, owned by Nexa Resources, is located in the state of Mato Gasso, Brazil. Aripuanã is a polymetallic underground mine that went through upgrades in 2022 that extend its operating life an additional three years, to a projected fourteen14, with a nominal production target of 6,065 metric tpd.
Several mining methods are employed at the site including bench stoping, longitudinal retreat, and transverse stoping, as well as both cemented and paste backfill. As part of the backfilling operations Nexa Resources enlisted the consulting engineering firm, Minefill Services, to issue a tender package to begin the procurement process for the paste pumps in 2019.
After evaluation of the received offers, three model KSP 220 H(HD)XL piston pumps were selected to deliver up to 150 m3/hr. of cemented tailings at pressures up to 130 bar. The pumps are powered by 600 kW power units, each comprised of two 300kW motors. The power pack systems also include a customized sound attenuation enclosure to limit sound levels while operating to no more than 85dBA.
The dual motor configuration in the power pack provides redundancy as, in the event of an unexpected failure of a motor or hydraulic pump, the pump can continue to operate at half capacity with only half of the power unit functioning. This allows the site to either complete the pour or allow the pipeline to be cleared until repairs can be made.
The piston pumps are also equipped with Schwing Bioset’s proprietary Ideal Control Circuit (ICC) technology that is internal to the pump design. The ICC is a dampening system that mitigates undesirable pressure transients in the pipeline that, are at times, observed with piston pumps by alternately ramping pumping speed down at the completion of a pumping stroke and gradually ramping up speed at the beginning of each new pumping stroke. This ramp up/down feature controls the material velocity in the pipeline and prevents the abrupt changes in material momentum that may otherwise induce water-hammer in the pipeline.
Another feature of the selected pumps is the inclusion of the optional Paste Flow Measuring System (PFS). The PFS will measure to within +/- 5% the volume of paste that has been pumped. This provides useful operating data that can be trended over time to schedule maintenance activities by tracking the overall performance of the pump and trending wear rates of replaceable components. The PFS also allows verification of the volumes of paste pumped to each stope to ensure the cavity has been adequately filled.
These features, combined with Schwing Bioset’s reputation for high-quality reliable equipment and aftermarket support, made the pump selection an easy choice. To learn more about our piston pumps, visit our website here, or feel free to contact Chuck Wanstrom.