Radar Head for Borehole Charge Level Detection
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Solution Overview
Problem
Current methods for charging blasting boreholes with flowable explosives in open-cast mining often result in uneven explosive distribution due to large depths and curvatures, leading to suboptimal blasting results and laborious comminution processes, as radar measurements are unreliable and cannot accurately determine charge levels in deep, non-cylindrical boreholes.
Innovation Solution
A radar head with a radar unit operating in the non-rock penetrating frequency range is used to detect the charge level and shape of the borehole jacket section, allowing for precise explosive distribution by measuring the vertical distance of the radar head above the charge level and calculating the explosive quantity, enabling real-time monitoring and adjustment during charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If radar measurements are used to determine charge levels in deep boreholes, then measurement capability is provided, but measurement precision deteriorates due to large depths and curvatures exceeding the Fresnel zone
Solution Approach 1:
The radar measurement process is segmented into multiple sections along the borehole depth. Instead of attempting to measure the entire borehole depth in one measurement, the system divides the measurement into segments that can be individually measured and then integrated to determine the complete charge level distribution throughout the borehole
Solution Approach 2:
The system transitions from one-dimensional depth measurement to three-dimensional spatial mapping by incorporating angular position data and radial distance measurements. This dimensional expansion allows the radar to accurately determine charge levels even in curved boreholes by mapping the charge distribution in spherical coordinates rather than relying solely on linear depth measurements
2Manufacturing precision
If constant quantity of explosive is charged, then charging process is simplified, but manufacturing precision deteriorates due to uneven explosive distribution in the borehole
Solution Approach 1:
The radar measurement system provides real-time feedback on the actual explosive distribution within the borehole during the charging process. This feedback information is fed back to the charging control system, which automatically adjusts the charging rate and distribution to achieve uniform explosive placement, creating a closed-loop control system that maintains high manufacturing precision
Solution Approach 2:
The charging system transitions from a static constant-rate charging approach to a dynamic adaptive charging process. The charging parameters (rate, position, distribution) are continuously adjusted based on real-time radar measurements of borehole geometry and existing charge distribution, allowing the system to adapt to varying borehole conditions and maintain optimal explosive distribution throughout the process
3Reliability
If radar operates in non-rock penetrating frequency range, then measurement reliability improves for charge level detection, but measurement capability deteriorates for deep borehole penetration
Solution Approach 1:
The radar system segments the deep borehole into multiple measurement zones, each measured with reliable detection frequencies. By dividing the total depth into manageable segments and measuring each segment individually with high-reliability frequencies, the system achieves both reliable detection and deep penetration capability
Solution Approach 2:
The radar system employs periodic measurement cycles where it alternates between different frequency ranges optimized for different depth zones. This periodic switching allows the system to use high-reliability frequencies for near-field measurements and lower-frequency penetration modes for far-field measurements, combining the benefits of both approaches
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
This solution ensures accurate explosive distribution along the borehole depth, improving blasting outcomes by allowing for controlled and efficient charging of deep, small-diameter boreholes, reducing the need for subsequent comminution and enhancing operational efficiency.
Implementation Method 1
A radar head with a radar unit operating in the non-rock penetrating frequency range is used to detect the charge level and shape of the borehole jacket section
Data Source
AI summary
A method and apparatus for controlled charging of blasting boreholes with a flowable/pourable explosive, in particular in open-cast mining, includes: providing a radar head with at least one radar unit operated in a non-rock penetrating frequency range; arranging the radar head on a pulling element; introducing the radar head into the borehole in that the radar head is lowered into the blasting borehole in an arrangement at the pulling means from an upper aperture opening of the blasting borehole; and detecting at least one measurement value comprising a base distance of the radar head from the blasting borehole base and/or a charge level distance to determine the charge level of the explosive in the blasting borehole; and/or comprising the shape of the jacket section over at least a portion of the depth of the blasting borehole by means of the operation of at least one of the radar units.