SBM project report: replacement of the dam wall Spitallamm

During the project power station Handeck 1 (CH), Kraftwerke Oberhasli AG (KWO) built a replacement dam wall in Spitallamm at Lake Grimsel. The new, double curvature arch dam is situated on the air side in front of the already existing dam wall finished in 1932. Its crest length comes to 195 m, the maximum height amounts to 113 m, which results in a concrete volume of 230,000 m3.

In 2019, the company SBM Mineral Processing GmbH was commissioned to supply two concrete mixing plants including recycling plant for the construction of the replacement dam wall Spitallamm at Lake Grimsel in Switzerland.

The project was already very sophisticated due to its location in a high alpine region (1,900 m above sea level) and the resulting short building season (April – September). This was made even more challenging by the ongoing Covid pandemic during the assembly phase.

Nevertheless, SBM Mineral Processing GmbH accepted the challenge, and in autumn 2020 the plant was handed over to the customer in time.

Between May 2021 and summer 2024 the new dam wall Spitallamm was built. Now, after 4 years of operation under the toughest conditions and before dismantling, the plant was visited and inspected by a delegation of the company SBM Mineral Processing GmbH. In an open dialogue with the plant managers on site, the construction and production periods were reflected on.

Conclusion: SBM Mineral Processing GmbH delivers what it promises – premium-quality, reliable and sophisticated plant technology for the most ambitious construction projects.

The management would like to express its thanks for the confidence placed in SBM Mineral Processing GmbH, the excellent and constructive co-operation, and for having been selected as a partner for this challenging project.

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Hard facts:

Timeline:

• Start of installation: June 2020
• Completion of the plant: September 2020
• Start of production: May 2021
• End of production: September 2024
• Production period: 4 years at 5 months = 20 months

Static requirements

• Snow load 1,700kg/m2
• Wind speed 210km/h
• Safety against snow avalanches

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Concrete output: Within 20 months a total of 230,000 m3 of hardened concrete was produced:

• 2021 – 30,000 m3
• 2022 – 85,000 m3
• 2023 – 75,000 m3
• 2024 – 40,000 m3

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Grain fractions: 0 - 4 mm, 4 - 8 mm, 8 - 16 mm, 16 – 32 mm, 32 – 63 mm and 63 – 120 mm

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Maximum performance of the twin plant: In 2022 and 2023, several peak production outputs of 1,100 m3/day (duration 18h/day) were achieved continuously over 7 days per week.

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Cement delivery: 5-6 silo lorries/day at peak times

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Technical data of the plants: 2x LINEMIX? 3500 CM 800-6 H

• 2x 800 m3 aggregate store in 6 chambers
• Aggregate feed by conveyors with 600 t/h conveying capacity.
• 2x 3.50 m3 BHS-twin shaft batch mixer for dams
• Total output capacity up to 210 m3/h of hardened concrete (2 plants)
• Concrete discharged to crane buckets with 7m3 cubic capacity and mixer trucks.
• 1,000 t cement store in 6 silos
• Hot air heating (with control system) for aggregates and hot water heating for concrete production for both plants
• Residual concrete recycling plant for both plants

Why mobile concrete mixing plants made by SBM?

Once construction is finished, the concrete mixing plants will be dismantled. SBM’s modular design allows for quick and easy relocation to new sites either together or separately.

Advantages of the mobile concrete mixing plants type LINEMIX? by SBM:

• Modular design for customised requirements
• Electric systems of the modules pre-installed and ready-for-production
• High-performance plants ensure premium concrete quality.
• Reliable concrete production just-in-time and in any weather
• Plants are as standard equipped with insulation casing.
• Easy maintenance and optimum service accessibility
• Excellent spaciousness (comparable to stationary plants)
• High economic efficiency