HH-Basalt & Diabase: Phased plant modernization during ongoing operation
The Oberscheld diabase plant of HH-Basalt- und Diabaswerk GmbH is one of three sites within this business segment of the Hermann Hofmann Group. The existing plant infrastructure has evolved over several decades and reliably supplies the regional construction industry with high-quality aggregates. In recent years, a need for modernization has become evident in the processing section at Oberscheld. The upgrade was to be implemented during ongoing operation, with the objective of ensuring long-term, reliable and maintenance-friendly production.
Project launch: Spare parts risk turned into
an opportunity for modernization
At the beginning of 2023, the operation faced the challenge of replacing its central secondary crusher, an Aubema gyratory crusher, due to increasingly limited spare parts availability. Sandvik was involved at an early stage, taking an active role in advising on and assessing the process engineering requirements to develop a solution tailored to the specific site conditions and fully aligned with the customer’s technical requirements as well as the constraints of ongoing operation.
“We chose Sandvik because of the reliability of the technology and the consistently high screening efficiency. The CS430 particularly stood out in this regard,” says Felix Hofmann, Deputy Plant Manager, HH-Basalt- und Diabaswerk GmbH. The decision was made in favour of the Sandvik CS430 cone crusher, including a steel structure adaptation to the existing supporting structure. Sandvik was commissioned with the engineering and implementation of the retrofit, combining equipment supply with a process performance guarantee. The project scope was further expanded by the installation of a new crane runway to support maintenance and servicing of the crusher. Since autumn 2023, the Sandvik CS430 has been reliably supporting production at the Oberscheld site from its central position in the processing plant.
Screening technology & material flow:
Modernization as an integrated system
Following the successful crusher project, Sandvik gained not only detailed insight into the existing plant but also a comprehensive understanding of the site-specific process requirements. Against this backdrop, Sandvik and HH-Basalt- und Diabas GmbH jointly developed a modernization roadmap that realistically accounted for the constraints of an existing installation while remaining fully compatible with ongoing operations.
The next phase therefore shifted the focus away from individual machines to the performance of the entire material flow. In early 2024, the decision was made to proceed with the next development stage of plant modernization. This included the installation of additional plant equipment, consisting of two new Sandvik screening units and a new drive concept for the push feeder, upstream in the primary crushing station.
At the Oberscheld site, this was implemented in two stages. First, an SJ2168 three-deck circular motion screen with dimensions of 6.0 m x 2.1 m was commissioned. In addition, the existing push feeder feeding the primary crusher was upgraded with a hydraulic power unit HPY 600 (SH series), replacing the previous mechanical gearbox. In early 2025, this was followed by the installation of an SJ1547 two-deck circular motion screen with dimensions of 4.0 m x 1.5 m. Both screening units were genuine Sandvik rubber screen panels.
This marked another significant step towards increased operational reliability and an improved maintenance concept. This is particularly critical in screening operations, where downtime must be kept to an absolute minimum.
Practical innovation: Lightweight dust covers
A visible result of this approach is the integration of innovative GRP lightweight dust covers on the Sandvik screens. These covers were developed by Sandvik in cooperation with LSE GmbH, an engineering partner with extensive expertise in lightweight design. At the Oberscheld site, the GRP covers are now installed on all screening units. “These dust covers are so light that they can be handled by a single person. At the same time, they effectively absorb noise and contribute significantly to noise reduction,” explains Norbert Schramm, Managing Director of LSE GmbH. Unlike heavy steel covers, which often require days of disassembly, the replacement or installation of these lightweight covers can be completed within a very short maintenance window of approximately one hour.
In addition to significantly improved maintenance efficiency, the solution also enhances environmental protection and occupational safety by reliably containing dust emissions and reducing noise levels, thereby providing definite advantages for an operating quarry.
Modernising existing plants:
Partnership as a key success factor
From a technical perspective, modernizing an existing plant is rarely a straightforward installation task. At Oberscheld, several challenging boundary conditions had to be addressed, including limited space, coordination with existing structures and statics, maintenance access requirements, occupational safety considerations and uninterrupted operation. Success therefore resulted not only from equipment quality, but from a genuine partnership. “Sandvik stands out in particular for the quality of its technical consulting, engineering and the development of innovative, practical solutions,” says Felix Hofmann.
Throughout the entire project, Sandvik worked closely with the operator, carried ouwt detailed site assessments and process analyses, and translated requirements into practical, implementable solutions tailored specifically to the Oberscheld site.
Ready for the next step:
Additional screening unit in planning
Today, the Oberscheld site demonstrates what modernization of an existing plant can achieve when technology, engineering and operational practice are consistently aligned. The installed solutions are designed not only for high performance, but above all for continuity and reliability. Low downtime, consistent screening results and stable product gradations ensure high production reliability and product quality. At the same time, the innovative, maintenance-friendly design of the screening covers significantly reduces effort during screening maintenance and makes downtime more predictable.
Sandvik has proven to be a partner that remains reliable and accessible from project engineering through to after-sales support. The smooth day-to-day operation at the Oberscheld diabase plant to date is the best evidence of this. A further screening unit is currently in the engineering phase and is scheduled to be integrated into the existing plant and commissioned in 2026.
