The term shooting shaft comes from blasting technology and essentially describes a vertical or steeply inclined borehole or a short shaft used to place and detonate explosive charges in rock or concrete. In practice, it is encountered in mining and tunnel construction, in quarries, and in certain deconstruction measures. Increasingly, however, shooting shafts are being complemented or replaced by controlled, low-vibration methods, such as hydraulic rock and concrete splitters or concrete demolition shear, when vibrations, noise, or permitting requirements restrict blasting.
Definition: What is a shooting shaft
A shooting shaft is a purpose-built, usually vertical borehole with sufficient depth and a defined diameter that accommodates explosives, initiation systems, and stemming material. The goal is to generate stress and fracture lines in the surrounding material in order to release, fragment, or prepare rock or concrete. Depending on the application, terms such as blast hole, charging hole, or blasting shaft are also used in technical jargon. A shooting shaft is to be distinguished from hoisting shafts or exploratory boreholes, as its primary function is focused on shooting (controlled blasting).
Technical design and mode of operation
The shooting shaft follows blasting principles: it is made with suitable drilling technology/methods, then charged and properly stemmed (backfilled) to channel the detonation energy. The central task is the controlled release of energy along a borehole pattern plan.
Geometry and drilling technology
Diameter and depth depend on material strength, desired block size, and safety requirements. In rock, borehole patterns and spacings are typically larger than in reinforced concrete. In massive foundations or bridge decks, short, closely spaced boreholes are often used that are functionally equivalent to a shooting shaft.
Charging, initiation, stemming
The charge is placed in stages, fitted with delays, and stemmed with inert materials to prevent blowouts. The initiation pattern aims at directed fracture propagation. In confined situations, small explosive quantities and tight delays are used to minimize vibrations.
Operating principle and fracture pattern
The energy released in the shooting shaft generates pressure and shear waves that exploit existing planes of weakness or create new cracks. The aim is a predictable fracture pattern that simplifies subsequent steps—such as removal with concrete demolition shear or targeted splitting.
Fields of application: mining, concrete demolition, and rock works
Shooting shafts are classically anchored in rock excavation and tunnel construction as well as in natural stone extraction. In concrete demolition and special demolition, functionally comparable blast holes are produced in massive components, for example for pre-fragmentation. In urban settings, these methods compete with or are combined with mechanical alternatives. In building gutting and cutting, blasting is often completely dispensed with; mechanical separation methods and hydraulic tools are used instead.
Planning, permits, and safety
Blasting works with a shooting shaft are subject to strict legal and technical requirements. These include the qualification of the responsible personnel, hazard analysis, safety distance, barricading and warning concepts, as well as vibration and dust management. Depending on the location and task, official notifications or permits may be required. Emission control, neighbor protection, and documentation play a central role. The information provided must always be interpreted project-specifically and does not replace binding advice.
Alternatives to the shooting shaft: controlled splitting and separation
Where blasting is not indicated for legal, technical, or environmental reasons, mechanical methods are available. Particularly established are hydraulic splitter, rock splitting cylinders, and concrete demolition shear. They enable a predictable, low-vibration approach in areas with sensitive structures or during ongoing operations.
Hydraulic splitter in massive rock
After creating boreholes with diameters suited to the splitting system, cylinders are inserted and pressurized hydraulically. The resulting splitting pressure opens the rock along predefined lines. These rock splitters are suitable in rock excavation and tunnel construction for starter niches, enlargements, or selective removal of overbreak.
Concrete demolition shear in selective deconstruction
Concrete demolition shear separates concrete elements while simultaneously exposing or downsizing the reinforcement. In combination with a steel shear, a continuous process is created—from releasing to size reduction to source-separated sorting—typical in concrete demolition and special demolition as well as in building gutting and cutting.
Hydraulic power pack as the energy source
A hydraulic power pack provides the energy required for splitting cylinders, shears, and cutters. Selection criteria include flow rate, pressure level, transportability, and the operating environment (e.g., tunnels with strict exhaust and noise limits). A coordinated setup of hydraulic power units increases efficiency and process safety.
Workflow: From the shooting shaft to mechanical separation
Many steps in blasting preparation can be used for mechanical methods. Boreholes initially intended as a shooting shaft can often be used directly for splitting cylinders. A practical sequence might look like this:
- Surveying and defining a drilling or splitting pattern with target fracture lines in mind.
- Producing boreholes with a diameter and center spacing suited to the splitting system.
- Pre-weakening with hydraulic splitter until cracks form.
- Follow-up work with concrete demolition shear for separation, profiling, and size reduction.
- Cutting reinforcement or embedded components with steel shear; if necessary, cutting tanks and hollow bodies with tank cutters.
- Source-separated sorting and removal.
Vibrations, noise, and dust: impacts compared
Depending on the charge and delay, shooting shafts generate measurable vibrations (e.g., as vibration velocity) as well as short-term noise peaks and dust release. Mechanical methods are generally low-vibration and continuous, simplifying prediction and shielding. For sensitive infrastructure (laboratories, hospitals, historic structures), hydraulic splitter and concrete demolition shear are therefore often the first choice.
Typical sources of error and how to avoid them
- Unsuitable borehole diameter: leads to incomplete fragmentation in blasting, or insufficient splitting effect in splitting methods.
- Incorrect borehole depth or alignment: deviations impair the fracture line and follow-up work.
- Insufficient stemming in the shooting shaft: increases the risk of blowouts and damage.
- Excessive borehole spacing: requires higher charges or causes uneven results during splitting.
- Underestimated hydraulic power: reduces the effectiveness of splitting cylinders, concrete demolition shear, and shears.
- Poor dust and water management: impairs visibility, reduces tool life, and may exceed limit values.
Practical examples from the fields of application
In tunnel construction, shooting shafts can be used in advance to break hard rock. In noise-sensitive sections, the team switches to splitting cylinders to carry out profile corrections with low vibration. During the deconstruction of a massive foundation block in an inner-city location, boreholes are initially planned for possible blasting. Due to vibration limits, they are used directly as splitting holes; subsequently, concrete demolition shear shape the target profile. In natural stone extraction, splitting along natural joints enables the recovery of dimensionally accurate blocks, while shooting shafts are used more for primary extraction and loosening.
Terminology and variants
The shooting shaft differs from the classic blast hole mainly in geometry and depth of application. For inclined boreholes, one sometimes speaks of shot lines or shot holes. In concrete bodies, short, closely spaced boreholes are used as “shooting channels” to create local target fracture zones. Blind shafts, exploratory boreholes, or anchor drilling boreholes do not serve a blasting function.
Normative orientation and training (general)
Recognized rules of technology and the relevant regulations for handling explosives, occupational safety, and emission control apply to planning and execution. Blasting works are reserved for qualified personnel. For hydraulic separation and splitting technology, the usual safety and test requirements for pressure equipment, hoses, and couplings apply. Specific obligations depend on project, location, and jurisdiction.
Maintenance, equipment, and logistics
Drilling equipment, casing, and charging accessories must be matched to the material and shaft depth. For mechanical alternatives, the condition of hydraulic power pack, lines, and tool inserts is decisive. Regular visual and functional inspections, proper transport, and clean storage increase operational safety and reduce downtime.
Planning parameters and design aids
Planners consider material properties (strength, modulus of elasticity, jointing), geometry (member thickness, cover), and environmental requirements (vibration and noise limits). For shooting shafts, borehole patterns, specific charge per meter of borehole, and delay patterns are decisive. In splitting methods, borehole diameter, center spacing, and splitting force determine the result. In hybrid setups, a combination of splitting technology and follow-up work with concrete demolition shear is recommended to achieve target geometries precisely and efficiently.