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Author: Admin | 2025-04-28
The potential for flyrock, airblast and venting. In the past, burden poles were used to measure the face burdens.While burden poles are still used on some locations, operations increasingly are transitioning to contact-free profiling equipment to increase safety and burden measurement accuracy.With advancement in technology it is possible to determine the burden of the front row of holes using both two-dimensional and three-dimensional face profiling. Prior to drilling, a 2D face profile allows an individual to determine face profile (perpendicular cross-section of the blast face at that location) and adjust the hole location closer to or further from the face to obtain the optimal front row placement. Once the shot has been drilled, the face can be profiled to get the actual 2D cross section and burden for each hole in the front row. This gives the blaster or loading personnel the information required to load the front row more accurately and greatly decrease the chance for flyrock. This form of profiling is usually adequate for simple faces.For more difficult blast faces, it may become necessary to use a 3D profiling system to obtain a minimum burden view of each blasthole. Two types of systems that can be used are 3D laser profilers and 3D photogrammetry systems. The 3D laser takes many points on the face and creates a 3D mesh of the blast face allowing a person to design the front row to a more accurate face. It also gives the blaster or loading crew the same options as far as the 2D cross sectional view for hole loading accuracy. A 3D photogrammetry system uses digital pictures of the blast face to create a high-accuracy 3D image of the blast face. It also gives the loading crew the ability to see the minimum burden, or burden on a 360-degree view for each hole. It can be used to design simple or difficult blasts and get the most accurate front row hole placement. A profile taken of an already drilled pattern allows the loading crew the most accurate burden view for loading purposes.3D profiling systems also can be geo-referenced to allow an operation to import the information into its mine planning software, drill navigations systems and blast design software.Using the face profiles generated from these systems, an operation can now place the holes in the front rows at the optimum burden, load them with greater accuracy and increase the overall safety, blast performance and cost efficiencies.BLASTHOLE LOADINGIt is important that holes be loaded correctly in accordance with the design. Improperly loaded holes can lead to poor fragmentation and/or excessive flyrock and airblast. The hole depths must be correct. Operators must decide how short a hole can be before redrilling is
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