A significant zinc mining operation in North Queensland operates the largest tailings re-treatment facility in Australia. Ranked among the top 15 global zinc producers, the site produced 118,108 metric tonnes of zinc in FY2022. However, the site faced challenges in maintaining optimal production efficiency due to frequent pipeline blockages, slurry density inconsistencies, and pump failures.
Reliable Dewatering for Safer, More Efficient Tunnelling: How Goodwin Brazil’s Submersible Slurry Pumps Transformed a Major São Paulo Rail Project
In the heart of São Paulo, one of Brazil’s largest infrastructure projects is underway—an ambitious expansion of the city’s underground rail network. With 14 kilometers of new tunnels and 12 stations under construction, the project has a total budget of $180 million and is key to easing congestion in one of South America’s most densely populated urban centers. However, large-scale underground construction is not without its challenges, particularly when it comes to groundwater management during tunneling.
During the critical excavation phase, the project encountered a serious operational obstacle: high volumes of silica-laden grout water collecting in tunnel sections. This issue not only compromised safety but also triggered costly delays. The eventual solution—implementation of a Goodwin 100 HNZB submersible slurry pump—proved instrumental in overcoming these difficulties and dramatically improving project efficiency and safety.
The Problem: Hazardous Grout Water Accumulation in Tunnels
Tunneling in unstable ground conditions necessitated frequent pre-grouting to stabilize the tunnel face and surrounding strata. While this technique improved ground stability, it introduced another issue—grout water pooling in the tunnel network. The high silica content in the water, a byproduct of the cementitious grouting process, created an abrasive slurry that was highly damaging to conventional dewatering systems.
Initially, water removal was attempted manually. Crews hauled water away using buckets and makeshift pumps, but this proved not only labor-intensive and hazardous but also ineffective. The presence of water consistently disrupted elevator access and tunnel excavation, halting operations regularly and placing the project timeline at risk.
The Ineffective First Attempt: Standard Pump Failures
Before adopting a specialized solution, the contractor tried deploying standard positive displacement and dirty water pumps. These units failed rapidly—sometimes within hours—because they were not designed to handle the high abrasiveness of silica-laden grout water. The result was frequent pump breakdowns, increased downtime, rising maintenance costs, and safety incidents due to waterlogged tunnels and unreliable access routes.
The Search for a Robust, Long-Term Solution
Realizing the limitations of conventional equipment, the construction management team sought a more rugged and dependable system—one capable of withstanding extreme conditions while maintaining reliable performance over long operational cycles. The team reached out to Goodwin Brazil, renowned for its robust slurry pump solutions, particularly in challenging environments like mining and heavy civil construction.
After site assessment and consultation, Goodwin’s engineers recommended the deployment of the Goodwin 100 HNZB submersible slurry pump, a purpose-built unit designed to handle high-density, abrasive fluids in deep and demanding environments.
The Game-Changer: Goodwin 100 HNZB Submersible Slurry Pump
The Goodwin 100 HNZB is a heavy-duty slurry pump with a 100mm discharge and a 30kW motor. Built for tough applications, it is engineered to handle slurries containing up to 70% solids by weight and is ideal for environments with abrasive particulates, such as silica.
Installed to pump water from depths of up to 40 meters, the 100 HNZB unit proved to be the ideal solution for the tunnel’s harsh conditions. The pump’s high chrome impeller, durable seals, and wear-resistant construction ensured long-term reliability despite the abrasive nature of the grout water.
Immediate and Long-Term Results
The impact was immediate. The Goodwin pump delivered continuous, reliable performance where other pumps had repeatedly failed. Downtime caused by pump maintenance dropped dramatically, and water removal was no longer a bottleneck in the construction process.
One of the most notable outcomes was the drastically reduced maintenance cycle. Where standard pumps broke down quickly under the abrasive load, the Goodwin pump operated for six months before requiring a simple impeller replacement—a maintenance task that could be performed directly within the tunnel in under two hours.
This reliability translated into multiple benefits:
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Elimination of Manual Water Removal: Reducing labor requirements by automating the dewatering process removed workers from hazardous environments and freed them to focus on core construction tasks.
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Uninterrupted Elevator Access: With tunnels free from pooling water, personnel and materials could be transported safely and consistently, improving operational flow.
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Reduced Downtime and Delays: The pump’s reliability ensured tunneling operations could continue without unplanned halts due to water ingress.
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Lower Operational Costs: Fewer pump replacements, reduced labor involvement, and minimal downtime all contributed to significant cost savings.
Why the Goodwin 100 HNZB Succeeded Where Others Failed
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Several factors contributed to the success of the Goodwin 100 HNZB in this environment:
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Designed for Abrasive Environments: Unlike general-purpose pumps, the 100 HNZB is specifically built to handle slurries with high solid content, such as silica from grout water.
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Heavy-Duty Construction: With hard-wearing components like high-chrome impellers and mechanical seals designed for high loads, the pump resists wear that destroys traditional pumps.
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Depth Capability: Its robust motor and hydraulic performance allowed it to function efficiently at 40m depth—a critical requirement in deep tunneling applications.
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Ease of Maintenance: The pump’s modular design and in-situ serviceability mean minimal disruption to operations when routine maintenance is needed
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A Scalable Model for Similar Infrastructure Projects
The successful deployment of the Goodwin 100 HNZB in São Paulo offers a scalable model for similar infrastructure projects throughout Latin America and beyond. Whether for rail, road, or hydroelectric tunneling, the ability to reliably dewater abrasive environments without excessive maintenance or labor makes Goodwin pumps a sound investment.
As cities expand and invest in complex underground infrastructure, project managers and civil contractors will increasingly face the need for specialized dewatering solutions. Standard equipment often cannot meet the demands of today’s construction environments, particularly when abrasive materials or depth constraints are involved.
Conclusion: Laying the Groundwork for Efficient Urban Growth
The São Paulo underground rail project underscores the importance of selecting the right equipment to match the demands of modern urban construction. In choosing Goodwin Brazil’s 100 HNZB submersible slurry pump, the project not only overcame a critical operational challenge but also safeguarded timelines, budgets, and worker safety.
By replacing failed conventional pumps with a purpose-built solution, the project team demonstrated that investment in specialized, durable equipment pays significant dividends in the long term. As São Paulo continues to modernize its transport infrastructure, Goodwin’s pump technology has proven to be a quiet yet essential contributor to progress—working deep underground to keep the city’s growth on track.
