The grading detection of calcium carbonate whiteness in open-pit mines is a crucial task that significantly impacts the effective utilization and refined processing of mineral resources. Traditional detection methods heavily rely on manual operations, resulting in low efficiency and susceptibility to subjective influences. Hence, the adoption of advanced detection technology is pivotal in enhancing the accuracy and efficiency of ore whiteness grading detection. This paper will introduce the application of spectral high-speed cameras in the detection of ore whiteness grading in open-pit mines.
There is a demand from clients for extensive detection of calcium carbonate whiteness in mines. However, the efficiency of detection through manual or handheld whiteness meters is low, necessitating a more efficient detection method.
For this grading detection, a spectral high-speed camera operating within the 400-1000nm range was employed. The research utilized the FS13 product from SpectralTech (Zhejiang) Co., Ltd. The spectral range covers 400-1000nm with a wavelength resolution superior to 2.5nm and up to 1200 spectral channels. The full-spectrum acquisition speed can reach 128FPS, with a maximum of 3300Hz after band selection (supporting multi-region band selection).
The initial phase involved placing four samples of ore on the conveyor and utilizing the FS-13 for detection, thereby obtaining the reflectance data for different whiteness levels of calcium carbonate within the 400-1000nm range.
From Figure 4, it is evident that the first and second levels of whiteness exhibit similarities. Based on the overall waveform, grouping the first and second levels into one category seems appropriate, while the distinction between the third and fourth levels is notably clear. The fourth level demonstrates a steep slope, contrasting with the lower slope of the third level. Additionally, the overall difference between these levels and the first two is significant, facilitating easy differentiation.
The technical team selected a piece of calcium carbonate with a whiteness level of two, as shown in Figure 6, and captured images from a distance of approximately 50 meters. After modeling and calibrating the curve in this spectral range, they performed an inversion on the ore depicted in the image. The red areas on the right image represent regions with calcium carbonate of the same second-level whiteness.
Using the 400-1000nm spectral camera FS-13 along with a stand for calcium carbonate whiteness grading detection is entirely feasible. However, it has been observed that the difference in reflectance between first-level and second-level whiteness is extremely minimal, with only two minor distinctions identified, as depicted in the figure below:
UAV-based Hyperspectral Detection
For future large-scale and efficient detection of calcium carbonate whiteness levels, the use of UAV-mounted hyperspectral measurement systems can be considered. These systems possess characteristics of high efficiency and low power consumption, enabling the acquisition of spectrally stable images with high stability.
The application of hyperspectral cameras in the grading detection of ore whiteness within open-pit mines has achieved significant success. Through the acquisition and analysis of spectral data using the hyperspectral camera, precise detection of ore whiteness has been achieved. This advancement has notably improved the accuracy and efficiency of detection while reducing errors associated with manual operations. It’s believed that in the future, with further technological advancements, hyperspectral cameras will play an even more substantial role in the field of ore whiteness grading detection within open-pit mines. This advancement will provide stronger technical support for the effective utilization and refined processing of mineral resources.