Dome Plate / Anchor Plate

Product Overview

Mining dome plates (also known as spherical bearing plates or arch-shaped trays) and anchor bearing plates are core load-bearing components in coal mine roadway rock bolt support systems. Their primary function is to uniformly transmit the pre-tightening force and working resistance of rock bolts/cables to the surrounding rock surface, expanding the support stress area, effectively preventing loose rock strata from falling, and improving overall roadway stability.

Core Advantages

High Load Capacity, Safe and Reliable

Manufactured by integral stamping of high-quality Q235B / Q355B steel plates, with hardness reaching HRC28-32 after quenching and tempering treatment. Load capacity ranges from 137kN to 902kN in multiple levels, and the three-point support compressive strength is not lower than the designed anchoring force of rock bolts, meeting support requirements of different surrounding rock grades.

Spherical Self-aligning Design, Adaptive Installation

Used in conjunction with self-aligning ball pads, the dome plate can automatically compensate for rock bolt installation angle deviations within 10°, preventing bolts from bending or shear failure due to uneven stress, significantly improving the overall reliability and service life of the support system.

Uniform Stress Distribution, High Support Efficiency

The arch-shaped spherical structure enables the bolt pre-tightening force to uniformly diffuse to the surrounding rock in a 360° direction, effectively expanding the compressive stress distribution range, reducing local stress concentration, preventing rock fragmentation and falling around the plate, and increasing the effective support area per single bolt.

Excellent Craftsmanship, Stable Quality

Adopting automated hot stamping production lines, the products feature high dimensional accuracy, with spherical curvature R40-R60 precisely controlled, and burr-free, crack-free edges. Surfaces can be treated with galvanizing, painting, and other anti-corrosion methods, adapting to underground humid and highly corrosive environments, with no deformation or rust during long-term use.

Product Specifications

Applications

Coal Mine Roadway Support

Widely used in rock bolt/cable support systems for various underground projects such as coal mine mining roadways, development roadways, and chambers. It is a standard load-bearing component for coal roadways, semi-coal rock roadways, and rock roadway support, effectively controlling roof subsidence and side deformation.

Metal and Non-metal Mines

Suitable for stope, roadway, and shaft support in various mines including iron ore, gold ore, copper ore, and gypsum mines, adapting to different rock properties and ground stress conditions, ensuring underground operation safety.

Tunnels and Underground Engineering

Used for initial support and advance support in railway tunnels, highway tunnels, water conservancy tunnels, underground powerhouses, etc. Used with hollow bolts and self-drilling bolts to improve the self-bearing capacity of surrounding rock.

Slope Treatment and Foundation Pit Support

In open-pit mine slopes, building foundation pits, mountain slope protection and other projects, used with prestressed anchor cables to uniformly transmit cable tension to the slope surface, preventing slope collapse and rock spalling.

Structural Details

Spherical Arch Structure

The center of the plate adopts a spherical隆起 design, with arch height ranging from 25mm to 60mm according to specifications. This structure enables the bolt pre-tightening force to uniformly diffuse around along the spherical surface, forming a conical compressive stress zone, significantly increasing the effective support range. Spherical curvature R40-R60 is precisely machined, perfectly fitting with self-aligning ball pads.

Center Hole Chamfer

The inner wall of the center hole is machined into a spherical chamfer,配合 with the outer spherical surface of the spherical nut/self-aligning ball pad to realize the self-aligning function. When there is deviation in the bolt installation angle, the ball pad can rotate freely within the spherical surface, ensuring the bolt always bears axial tension and avoiding eccentric shear.

Bearing Plane and Edge

The bottom surface of the plate is a flat bearing surface, fully contacting with the surrounding rock surface, with large stress area. The edges are smoothly treated without sharp burrs, ensuring safe installation without damaging mesh, steel belts and other supporting materials. The overall wall thickness is uniform, with no local thinning or cracking defects after stamping.

Self-aligning Ball Pad Matching

Each set of dome plates comes standard with a corresponding specification of self-aligning ball pad (hemispherical washer). The ball pad is made of forged steel or cast steel with high surface hardness and good wear resistance. The fit clearance between the ball pad and the plate spherical surface is reasonable, with flexible rotation without jamming, and can compensate for maximum 10° installation angle deviation.

FAQ

Q1: What is the difference between dome plates and ordinary flat plates?
A: Ordinary flat plates can only transmit axial force. When there is installation angle deviation in the bolt, it is prone to eccentric stress leading to bolt bending and fracture. Dome plates with self-aligning ball pads can automatically compensate for angle deviation, keeping the bolt always under ideal axial stress, with higher support reliability, especially suitable for underground construction environments where installation accuracy is difficult to guarantee.

Q2: How to choose the appropriate plate specification?
A: It is mainly selected based on three factors: bolt diameter, designed anchoring force, and surrounding rock conditions. General principles: bolt diameter 16-18mm select Φ120-Φ150 plates, 20-22mm select Φ150-Φ180 plates, 24mm and above select Φ200 and larger plates; plate load capacity should be no less than 1.2 times the bolt designed anchoring force; for working conditions with broken surrounding rock and high ground stress, larger specifications and higher load capacity plates should be selected.

Q3: How is the plate load capacity tested?
A: According to MT/T 146.2 standard, the three-point support test method is used to test the load capacity of the plate, that is, placing three equidistant support points under the plate, applying concentrated load above, and measuring the load value when the plate reaches the specified deformation or failure. All our products undergo sampling load capacity testing before delivery to ensure performance compliance.

Q4: Can dome plates be reused?
A: Plates are support consumables and are not recommended for reuse after normal support use. Because the plate will undergo plastic deformation during the process of bearing surrounding rock pressure, and the internal stress state has changed, reuse may lead to reduced load capacity and safety hazards. For plates that are unstressed or slightly stressed, they can be considered for secondary use only after passing professional inspection.

Q5: What anti-corrosion surface treatments are available?
A: The standard is natural color (rust preventive oil protection). Hot-dip galvanizing, electro-galvanizing, painting, plastic spraying and other surface treatment methods can be provided according to customer requirements. Hot-dip galvanizing is recommended for humid underground environments with longer anti-corrosion life; painting or plastic spraying can be selected for projects with higher appearance requirements.

Contact Us for Custom Solutions

Every support project has its unique geological conditions and design requirements. With more than ten years of R&D and manufacturing experience in mining support products, we can provide one-on-one product selection and customization services according to your specific working conditions. Our customization scope covers special size and thickness plates, high-strength materials (Q460, Q550, etc.), special shapes such as star/diamond shapes, diversified surface treatment methods, as well as complete sets of bolt/plate/nut support solutions. Welcome to provide engineering drawings, technical parameters or samples, and we will issue professional product solutions and quotations within 24 hours.