Mine and quarry highwalls are dynamic structures that change shape as mining, blasting, scaling and weathering continue. Engineering solutions to control localized rockfall are different than those which control large scale slope instability.
Common highwall problems include:
Any given highwall may have periods where it appears stable. Behaviour may change after blasting, rainfall, excavation at the toe or overall pit geometry changes.
These functions should be evaluated separately.
| Function | Primary objective | Typical measures |
| Local block reinforcement | Prevent or limit movement of identified blocks or wedges | Rock bolts, dowels, long bars or anchors |
| Surface retention | Restrain smaller fragments close to the face | Anchored mesh, welded mesh or shotcrete where designed |
| Overall slope stabilization | Improve stability of a large slope mass | Geometry changes, drainage, reinforcement, buttressing, controlled excavation or other engineered measures |
| Rockfall control | Guide detached rock to a controlled area | Draped mesh and maintained catch benches |
| Rockfall interception | Stop moving rock before it reaches personnel or equipment | Energy-rated barriers, catch fences or protective structures |
| Hazard monitoring | Detect movement or deterioration | Surveying, prisms, radar, extensometers, crack monitoring or remote sensing |
| Exposure control | Keep people and equipment away from hazardous areas | Exclusion zones, barricades, operating procedures and alarms |
Rock bolts may stabilize a defined block but cannot be assumed to stabilize the entire highwall. Monitoring may provide warning but does not create physical stability.
Wanfeng provides support and face-connecting components that can be part of a mine’s ground-control solution.
Rock bolts, dowels and cablebolts may bridge discontinuities to tie visible loose rock to stronger rock. Bearing plates and steel straps help spread loadings at the face. Mesh specified by the project can be used to help contain smaller rocks between bolt attachments.
Depending on the mine’s plan, these components may connect to or influence:
Please note that these additional controls are not Wanfeng products unless specifically confirmed.
Functions of a System
The proper engineered set of components can be used to:
Engineering Disclaimer
Pit slopes, bench heights and widths, final slope angle, catch bench width, layout and angle of bolts, bolt lengths, bolt spacing, bolt type and lengtheners, bar/mesh strength, drainage, monitoring and exclusion considerations should be determined by or reviewed by professional mining, geotechnical and geological engineers familiar with highwall stabilization.
Considerations including but not limited to:
Wanfeng can only provide components to meet specified requirements and does not assume responsibility for the mine’s ground-control plan, examination of the highwall or stability of the slope.
1.Rock Bolts / Highwall Reinforcement Bolts
Steel reinforcing elements that can be installed through discontinuities or potential sliding surfaces to stabilize localized loosened rock masses.
Critical specification parameters
Other common parameters
2. Fully Grouted Threaded Bars & Dowels
Threaded reinforcing bars designed to be fully-grouted at project specific depths for use in highwall or bench reinforcement applications.
Critical specification parameters
Other common parameters
Specification note
The application of the bar as a tensioned bolt or untensioned dowel should be specified.
3. Cable Bolts / Long Reinforcement
Lengthy reinforcing elements that can be used to bridge unstable areas where a failure plane extends beyond the typical maximum length for rock bolts.
Critical specification parameters
Other common parameters
Specification note
Cable bolts are NOT inherently a permanent geotechnical anchor solution. Cable bolts still require project specific anchorage arrangement details, load-transfer mechanics, proof-testing requirements and durability considerations.
5. Coupled Reinforcement Bars
Segmented threaded bars used in applications where pinning oversized lengths through a coupler is necessary due to access restrictions, transport limits or overall length of reinforcement required.
Critical specification parameters
Other common parameters
5. Bearing Plates
Steel plates used at the highwall surface to help transfer and distribute the load of the reinforcement elements.
Critical specification parameters
Other common parameters
Specification note
Thin or highly fractured material present at the collar area may necessitate a larger load-distribution solution. Engineering judgment is required when selecting plate size based on local ground conditions.
6. Welded Wire Mesh
Steel mesh panels that can be used for localized surface restraint or incorporated into a reinforced shotcrete solution.
Critical specification parameters
Other common parameters
Specification note
Catalogued welded wire mesh should never be advertised as meeting rockfall barrier standards. Abrasion/ravinement tolerance and impact interception can only be guaranteed by a tested system consisting of mesh, supporting posts, terminal cables, energy damping devices, rock anchors and proper foundation design.
7. Steel Straps
Steel straps can be used to help distribute tensioned restraint across multiple points of reinforcement. Straps can be flat or contoured to match the required surface profile.
Critical specification parameters
Other common parameters
8. Nut, Washers & Miscellaneous Items
Components used to complete installation of bearing plates and properly torqued reinforcement assemblies.
Critical specification parameters
Available configurations may also include:
| Typical condition or failure mechanism | Typical requirement | Products or systems that may be relevant |
| Isolated loose block | Localized block restraint | Rock bolt or dowel with bearing plate |
| Planar sliding along a persistent structure | Reinforcement across the potential sliding surface | Engineered bolts, dowels or anchors |
| Wedge formed by intersecting joints | Reinforcement oriented across controlling discontinuities | Project-designed bolts or long reinforcement |
| Toppling blocks | Control of rotation and separation | Engineered bolts or dowels |
| Closely fractured bench face | Surface retention | Anchored mesh, welded mesh or shotcrete where designed |
| Ravelling of small fragments | Retention and maintained catchment | Suitable mesh with catch-bench management |
| Deep instability extending behind benches | Overall slope stabilization | Geometry modification, drainage, long reinforcement or other engineered controls |
| Weak or weathered collar zone | Wider surface load distribution | Suitable plates, washers, straps or reinforced facing |
| Water-bearing discontinuities | Reduction of water pressure | Horizontal drains and surface-water diversion |
| Blast-damaged face | Scaling, reassessment and localized reinforcement | Bolts or mesh only after the damaged zone is evaluated |
| Old underground workings behind highwall | Assessment of voids, pillars and subsidence potential | Mine-specific investigation and ground-control design |
| Highwall mining or auger openings | Web, pillar and highwall stability | Specialized highwall-mining ground-control analysis |
| Rockfall directed toward a catch bench | Controlled descent and collection | Engineered draped mesh and maintained catchment |
| Rockfall exposure above active work areas | Impact interception and exposure control | Rated barriers, protective structures or exclusion zones |
| Active or accelerating slope movement | Immediate risk management | Withdrawal, exclusion, monitoring and engineered reassessment |
| Long-term exposed support | Durability and inspection | Products with verified corrosion protection and traceability |
Selection Guide
CAUTION: This chart is intended as a starting point only.
An appropriate highwall support system is dependent on addressing the mechanism of failure. For instance:
You may need to investigate further or provide special controls if your highwall has:
Highwall mining openings
Movement that is progressive or accelerating
Ambiguous geology
In these situations, localized steel reinforcement may be only one component of overall risk controls.
Note on Highwall Mining Applications
“Highwall mining” may also be used to describe remote mining of coal or another seam. This is accomplished through openings that are drilled horizontally into a highwall at a surface mine.
Additional considerations include:
Stability of web and barrier-pillars
Products featured on this website are not intended to be sold as a complete mining design solution for highwall mining. Layout of extraction and design of pillars needs to be performed by a qualified mine engineer.
Wanfeng has the capability to review approved reinforcement schedules and plans to determine manufacturing feasibility. Items that can be customized include:
Please confirm material type, dimensions, tolerances, working loads and coatings on approved drawings or technical specifications prior to releasing for production.
Raw Material
Bar, Bolt and Thread
Mechanical and Connection Test
Contractually required and if applicable:
Dimensional
Surface Preparation / Coating
Marking and Final Inspection
Certificates
If claimed, publish the following:
NOTE: ASTM, EN, ISO, AS/NZS or Project Standards to only be shown if the product supplied conforms to the standard.
Factory tests confirm component properties. They do not establish installed anchorage or overall highwall stability.
| Test or inspection | Typical location | Purpose |
| Steel tensile test | Factory or approved laboratory | Verify material properties |
| Coupler tensile test | Factory or laboratory | Verify connection capacity |
| Cable breaking-load test | Factory or laboratory | Verify cable capacity |
| Bearing-plate inspection | Factory | Verify material and dimensions |
| Mesh weld test | Factory or laboratory | Verify specified weld strength |
| Coating inspection | Factory | Verify coating requirements |
| Bolt pull or proof test | Mine site | Assess installed anchorage performance |
| Grout record | Mine site | Document installation quality |
| Borehole log | Mine site | Record depth and encountered conditions |
| Geological mapping | Mine site | Identify discontinuities and hazards |
| Slope monitoring | Mine site | Detect movement or changing behavior |
Factory bar tensile strength must not be presented as proof that the installed support can resist the identified slope load.
Installation of highwall support can place workers in the face of the instability problem that is being remediated. The work plan approved for installation may need to specify:
Any person shall be permitted beneath a suspected unstable highwall merely because installation of reinforcement was scheduled, but not completed and confirmed.
Items that may be identified during the mines examination and monitoring program include:
Trigger-Action Principle
Trigger and response action thresholds should be established before triggering movement occurs. Responses may consist of, but are not limited to:
Wanfeng reserves the right to decide site alarm thresholds and will not authorize personnel to enter a highwall hazard zone.
1. What is highwall support?
Highwall support consists of engineered solutions that help control instability within a mine or quarry face. Elements applicable to a given hazard can include geometry adjustments, scaling, drainage, rock reinforcement, surface retention, catch benches, barriers and monitoring.
2. How are rock bolts used in highwalls?
Rock bolts or dowels can be used to cross joints and potential failure surfaces to restrain identified blocks or wedges. The location, orientation, length and anchorage of bolts should be determined by geological mapping and engineering analysis.
3. Can bolts stabilize an entire open- pit slope?
Not necessarily. While bolts can be used to help control defined local or intermediate scale instability, a deep or overall slope failure can require geometry adjustments, drainage, long-term reinforcement, buttressing or mine planning adjustments.
4. What is the difference between anchored mesh and draped mesh?
When installed correctly, anchored mesh is fixed to the slope and can restrain material against the face of a slope. Draped mesh does not cling to the face, and will generally guide detached rock toward a catch bench or catch area. These are different functions that require different capacity considerations.
5. Can welded wire mesh be used as a rockfall barrier?
Standard welded wire mesh can be used for local surface retention where properly designed, but should not be promoted or sold as an impact rated barrier without comprehensive system testing.
6. How should bolt length and orientation be selected?
Bolt length and orientation should correspond with the location and orientation of controlling discontinuities or potential failure surfaces. It is critical that reinforcement extends beyond these into material capable of developing adequate anchorage.
7. Why is drainage important for highwall stability?
Water can contribute to high pressure in discontinuities, reduced shear strength, weak infill, and weathering. Drainage and runoff control should be considered alongside reinforcement to improve stability.
8. Can Wanfeng manufacture your products according to mine drawings?
Yes. Wanfeng can review approved drawings for critical items such as dimensions, materials, threads, allowable loads, coatings, testing requirements and production feasibility. Final design responsibility remains with the mine’s engineering staff.
