Assessment of blasting impacts on the discontinuities in a salt stope and pillar mine using a developed image processing

Salt rocks exhibit a complex mechanical behaviour by reflecting large deformations at low deviatoric stresses. Since the propagation and creation of cracks due to blasting can disrupt the mine safety and cause irreparable failures in underground spaces, it is important to assess the impacts of blasting on different parts of a salt stope and pillar mine after each blasting round. This study assessed the impacts of blasting operation on discontinuities in a salt stope and pillar mine by using a developed image processing-based methodology. Various photo samples were collected from different parts of the mine pillars and walls. Photographs were taken at four different blasting rounds before and after each round. The Sobel filter for edge detection was developed in Matlab, and the photographs were processed to assess the impacts of blasting on the discontinuities. The assessment was performed by comparing the processing results before and after each blasting round for the photographs. The effects of distance from blasting points, detonation direction and the amount of charge per each blasting round were considered in the assessment process. The amount of charge per blasting rounds and distance from the blasting points indicated higher effects than detonation directions. The assessment results indicated that the impacts of the blasting operation on the discontinuities decreased and became almost ineffective at distances greater than 30 m. Also, the points located at the end of the mine, as a closed space, experienced the greatest impact of the blasts.