Robotic Thin Spray-On Liner Applicator for Mine Rock Support
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Solution Overview
Problem
Existing methods for applying secondary rock wall and ceiling support in underground mines, such as shotcrete with wire mesh, are labor-intensive, prone to brittleness, and have long curing times, which can hinder productivity and safety in deep mining operations.
Innovation Solution
A robotic applicator system that uses a thin spray-on liner material, applying a high-performance polyurea coating with a robotic arm capable of precise movement and control, allowing for efficient and rapid application of a liner material to contoured surfaces, such as rock faces, by sensing surface grid points and determining a spray path to follow the topographical profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If shotcrete with wire mesh is used for rock wall and ceiling support, then protection against rock falls is provided, but the application becomes labor-intensive and curing time increases
Solution Approach 1:
The invention extracts and eliminates the wire mesh component from the traditional shotcrete system, using thin spray-on liner material alone to provide ground support. This simplifies the application process, reduces labor intensity, and eliminates the need for mesh installation while maintaining rock fall protection capabilities.
Solution Approach 2:
The invention changes the material parameters by using thin spray-on liner material with superior tensile strength (up to or above 2.5 MPa) and significantly shorter cure times (as little as 20 seconds) compared to traditional shotcrete. This parameter change enables faster application and curing, directly improving productivity while maintaining reliability.
2Reliability
If shotcrete is used for ground support, then rock fall protection is achieved, but tensile strength is insufficient and material volume increases
Solution Approach 1:
The invention changes the material parameters by using thin spray-on liner material with superior tensile strength (up to or above 2.5 MPa) compared to traditional shotcrete which has long dry times to reach full tensile strength of about 1 MPa. This parameter change directly addresses the tensile strength deficiency while maintaining ground support capability.
Solution Approach 2:
The invention uses high performance polyurea coating containing reactive polyurethane or other suitable polymer dispersed into a polymerizable diluent, creating a composite material system that achieves superior mechanical properties including tensile strength and toughness, eliminating the need for wire mesh reinforcement.
3Reliability
If wire mesh is installed with shotcrete, then rock fall protection is enhanced, but handling and installation complexity increases
Solution Approach 1:
The invention extracts and eliminates the wire mesh component from the traditional shotcrete system, using thin spray-on liner material alone to provide ground support. This simplifies the application process, reduces labor intensity, and eliminates the need for mesh installation while maintaining rock fall protection capabilities.
Solution Approach 2:
The invention applies thin spray-on liner material directly to the rock surface, creating a localized, conformal coating that provides ground support exactly where needed. This eliminates the need for global wire mesh installation and simplifies the operation while maintaining protective functionality.
4Reliability
If shotcrete is used for ground support, then rock surface protection is provided, but surface smoothness is poor and dust accumulation increases
Solution Approach 1:
The invention changes the material parameters by using thin spray-on liner material that cures to a smoother surface finish compared to traditional shotcrete. This improved surface smoothness reduces dust accumulation, enhancing safety and cleanliness in the mining environment while maintaining surface protection capabilities.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system provides superior tensile strength, faster curing times, reduced material volume, and a smoother surface, enhancing safety and productivity by eliminating the need for wire mesh and minimizing downtime between rock blasts.
Implementation Method 1
locations of a plurality of surface grid points on the contoured surface may be sensed
Implementation Method 2
a spray path for a liner application device configured to emit a spray of the liner material may be determined
Implementation Method 3
TSL's may be formed using a high performance polyurea coating containing a reactive polyurethane or other suitable polymer dispersed into a polymerizable (i.e., capable of undergoing polymerization) diluent
Data Source
AI summary
A method and system for applying a liner material to a contoured surface, such as an exposed rock face in an underground hard rock mine, is disclosed. Locations of a plurality of spatially distributed surface grid points on the contoured surface may be detected so as to generate a representative topographical profile of the contoured surface. Based on the plurality of surface grid points, a spray path for a liner application device configured to emit a spray of the liner material may be determined. In some cases, the spray path may have a trajectory that follows the topographical profile of the contoured surface offset therefrom within a spray range of the liner application device. Liner material may then be sprayed onto the contoured surface while controlling the liner application device to undertake at least one pass of the spray path.