VALVE MAGAZINE Summer 2024

MINING CASE STUDY

comprehensive engineering approach to ensure the valve is properly designed to handle this abrasive service. This article explains valve sizing practices to account for changes in slurry fluid behavior during the mine start-up phase versus normal operation. The changes in slurry fluid properties impact valve sizing and throttling response, and if not accounted for with proper engineering practices, can lead to valve and piping failures, resulting in unplanned downtime and repairs. The article is a case study of an in-service valve that was analyzed after its installation at Newcrest Cadia in Australia, demonstrating the coarse particle flotation technology. Cadia is one of Australia’s largest gold mining operations, owned by Newmont Corporation, and is found in central west New South Wales nearly 155 miles (250 km) from Sydney. The company produces gold doré bars, or unrefined gold, from a gravity circuit and gold-rich copper concen trates from a flotation circuit, which is the process this case study involved. The concentrates are piped to a dewatering plant then exported. The customer required severe service control valves that were designed to handle the challenging flow conditions of tailings applications need to have proper engineering checks and balances to ensure reliable service. Customers like the Newcrest mine that deal with extreme abrasive processes, require product designers to have a design philosophy that ensures control valves for these processes provide the right control and the longest lifespan. This article proposes the following as a proven design philosophy approach: 1. Dedicated effort in sizing each valve for the full spectrum of process conditions. 2. Streamlining and optimizing flow components to reduce unwanted turbulence for the majority of the throt tling positions of the valve. 3. Using the toughest materials available for flow compo nents to slow the damaging effects of erosion. In this particular technology test and demonstration, the Newcrest mine installed a valve with the coarse particle flotation technology, that was designed with the consid erations above to mitigate the challenges in this tailings control application. In addition to evaluating typical process conditions covering minimum, normal and maximum flow conditions, the design engineer sought to understand the mine start-up flow conditions, which had vastly different

CASE STUDY Sizing of Tailings Tank Level Control Valves in Mining Applications Tailings tank level control valves in mining applications play a critical role in mineral processing, especially in the process of increasing water recovery, which is paramount for improving the environmental sustainability of mining projects. Tailings tank level control valves in mining applications play a critical role in mineral processing, especially in the process of increasing water recovery, which is paramount for improving the environ mental sustainability of mining projects. One example of this application in mineral processing is the tailings control valve at the bottom of an Eriez Coarse Particle Flotation circuit using HydroFloat technology. The throttling response, reliability, flow dynamics, wear resistance and sizing practices of the control valve in this critical service (crucial to the operation of the flotation cells) require a BY: AMIR EMAMI, P.ENG. & MARIA AGUIRRE, P.ENG., COMPANY: SPECIAL ALLOY FABRICATORS

Metal seated butterfly valve damaged due to control of abrasive media. Source: SAF

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VALVE MAGAZINE

SUMMER 2024