Natural stone processing combines geoscientific understanding with precise engineering. It spans from extraction in the quarry through controlled separation and shaping to surface finishing and installation. In practice, both traditional craft techniques and hydraulic methods play a role, enabling an low-vibration, controlled, and material-conserving process. Especially where natural stone meets concrete, steel, or existing structures—such as in concrete demolition and special demolition, in building gutting and cutting, in rock excavation and tunnel construction, and in natural stone extraction—hydraulic rock and concrete splitters, rock wedge splitters, hydraulic power packs, or concrete pulverizers are used depending on the task.
Definition: What is meant by natural stone processing
Natural stone processing refers to the entirety of methods by which naturally formed rocks are processed into rough blocks, slabs, shaped stones, components, or surface textures. This includes primary processing (extraction, separation, splitting), secondary processing (sawing, milling, drilling, grinding, polishing), as well as installation and deconstruction. The aim is dimensionally accurate shaping, a surface suitable for use, and the best possible preservation of material integrity—while observing safety, emission reduction, and structural boundary conditions.
Materials science: Rock types and their properties
The choice of method is guided by the rock’s fabric, mineral composition, and strength. Igneous rocks (e.g., granite) are compression-resistant and brittle; sedimentary rocks (e.g., limestone, sandstone) often show bedding planes and differing abrasiveness; metamorphic rocks (e.g., gneiss, slate) feature pronounced joints and foliation. These natural structures determine how crack guidance, drilling patterns, and splitting forces should be applied. In fine-grained, homogeneous rocks, crack propagation is readily predictable; in anisotropic rocks, borehole spacing and feed rates should be chosen more conservatively to avoid breakouts.
Process chain: From extraction to installation
Processing begins with detaching the material from the rock mass or block stock, followed by sizing into transportable units, precise cutting, and surface treatment. On construction sites, an interplay is often required: controlled splitting, followed by sawing or milling, spot drilling, and finally achieving the desired surface roughness.
Primary processing
For gentle extraction and block division, boreholes are drilled and forces are introduced via wedge-based tools or hydraulic systems. Concrete splitters and hydraulic wedge splitters as well as rock wedge splitters are established here because they generate low vibrations and guide the crack front along the drilling pattern. In noise-sensitive areas or underground (rock excavation, tunnel construction), this is an advantage over impact- or explosive-based methods.
Secondary processing
For dimensional accuracy and edge quality, separating and machining processes follow. These include sawing (block and frame saws, diamond wire saws on projects), milling, drilling, grinding, and polishing. Depending on the application, surfaces are flame-treated, bush-hammered, sandblasted, or satin-finished—always with an eye on slip resistance, glare-free surfaces, haptics, and cleaning friendliness.
Controlled splitting with hydraulic systems
Hydraulic splitting uses boreholes to build a defined tensile stress in the rock via wedges or cylinders. The method is low-noise and low-vibration, produces well-controllable crack paths, and can be applied safely in densely built-up areas, in existing buildings, and in geologically demanding situations.
Drilling pattern, splitting force, and crack guidance
Key parameters are borehole diameter, depth, and spacing. They are derived from rock strength, fabric, the desired block size, and the available splitting force. Homogeneous granite allows larger spacings than foliated rocks. Clean hole walls improve friction and reduce the force required. For uniform results, splitting operations are performed sequentially so cracks propagate in a controlled manner.
Hydraulic power packs and interfaces
Power is supplied by hydraulic power units with appropriately designed flow rate and pressure. In practice, robust hose routing, effective leakage protection, and ergonomic handling are important. Regular functional checks and the correct oil temperature ensure reproducible splitting performance, especially during long operating times or at low ambient pressure in tunnel construction.
Natural stone meets concrete: Separating, releasing, deconstruction
In refurbishment, deconstruction, and repair, natural stone components are often tied to concrete or steel—for example, foundation connections, load-bearing overlays, infill, or concrete jackets. Here, concrete pulverizers and hydraulic splitting systems complement each other: pulverizers open concrete cross-sections, expose reinforcing steel, and minimize tensile stresses in the adjacent natural stone. Subsequently, concrete splitters and hydraulic wedge splitters enable gentle release or sizing of the stone fraction.
Strip-out and cutting in existing structures
During strip-out, concrete infills, mortar residues, or cast-on parts can be removed with concrete pulverizers and various hydraulic shears (e.g., combination shears, steel shears). Where metal elements connect to natural stone—brackets, beams, tanks, plant components—multi cutters or a cutting torch support safe exposure before the natural stone is separated or split. This creates clean interfaces and reduces edge damage.
Areas of application and typical uses
- Natural stone extraction: Block detachment, rough-block division, dimension-accurate cutting management with minimal crack runout.
- Rock excavation and tunnel construction: Low-vibration removal next to sensitive structures, controlled face processing, profile corrections.
- Concrete demolition and special demolition: Selective release of stone–concrete composite systems, protection of adjacent components through limited input effects.
- Building gutting and cutting: Removal of built-ins, exposure of natural stone structures, preparation for precise saw cuts.
- Special applications: Work in noise-sensitive zones, in ATEX zones, or near protected fabric, where low emissions and controlled crack guidance are decisive.
Planning: Geology, structural analysis, and workflow
Robust planning is based on rock survey (joints, foliation, water flow), accessibility, edge distances to existing components, and subsequent load transfer. From this follow the drilling pattern, equipment selection, transport logistics, and emissions management (noise, dust, water). In existing structures, protection and support measures should be planned early, especially for composite elements of stone, concrete, and steel.
Drilling technology
Borehole diameter and depth depend on the chosen splitting system. Precise alignment, adequate flushing, and avoiding mouth enlargement are central quality criteria. In fissured rock, a more conservative drilling pattern with closer spacing is recommended.
Surface treatment and quality
The required surface quality depends on use and design. Criteria include roughness depth, flatness, edge quality, and color fidelity. Polished surfaces require stepwise grit changes and clean water management; flame-treated or bush-hammered surfaces require uniform tool contact and controlled feed motion.
Inspection and acceptance notes
Visual inspection, flatness measurement, and spot checks of roughness are proven. Edge spalling can be minimized through reduced infeed, sharper tools, and adapted clamping forces. Documenting drilling and splitting parameters facilitates reproduction in subsequent sections.
Occupational safety, emissions, and environmental protection
Safe work requires coordinated protection measures: dust and water management (dust extraction, binding, retention), noise control, mechanical safeguards for fall protection and against secondary break-off, as well as personal protective equipment. Hydraulic methods promote low vibration levels, which protects adjacent structures and sensitive uses. Legal requirements vary and must be observed in general; risk assessments should be project-specific.
Equipment selection and operation
Key factors are the required splitting force, component geometry, drilling pattern, accessibility, and the available hydraulic power. Hydraulic power packs must be checked for sufficient flow rate, effective cooling, and good portability. Concrete pulverizers are selected by jaw opening, blade geometry, and the mass ratio to the carrier machine; for natural stone in composite, a tuned dosing of the jaw force reduces edge risks.
Maintenance and tool life
Regular checks of wedges, pressure blocks, hoses, and couplings increase operational safety. Clean hydraulic fluid, proper venting, and adherence to service intervals ensure consistent performance. For pulverizers and shears, timely resharpening and correct contact pressure extend cutter life.
Sustainability and circular economy
Low vibrations, targeted crack guidance, and precise separation reduce material losses, consequential damage, and emissions. Selective deconstruction facilitates clean separation of natural stone, concrete, and metal—a benefit for reuse and recycling. Water circuits and dust suppression systems further improve the environmental performance.
Typical mistakes and how to avoid them
- Unsuitable drilling pattern: leads to uncontrolled cracks—adjust borehole spacing to fabric and splitting force.
- Overloading in composite: jaw forces too high next to sensitive natural stone—choose a stepwise approach and intermediate relief.
- Insufficient emissions control: dust and water without retention—plan logistics and recirculation early.
- Lack of documentation: hinders reproducibility—record parameters and results section by section.
Practice-oriented procedure
- Perform rock and existing-structure analysis (fabric, joints, composite interfaces).
- Define the method mix (splitting, sawing, milling, shear work) and the drilling pattern.
- Align equipment and hydraulic power packs for capacity, clarify access and load paths.
- Implement emissions and protection concept, perform a trial cut or trial split.
- Execute section by section, measure, document, and adjust parameters as needed.