Burden Profiling: Do You Measure What You Think You Do?

摘要

Mining, quarry, and construction blasts are becoming more and more dependent on bench profiling. Theuse of accurate profiling gives the blaster better data for the most efficient blast results. So, we ask thequestion: What is the best method for measuring and analyzing burden?The seemingly straightforward question defeats an easy answer, because existing methods measureslightly different features of the burden with their distinct error profiles.To better answer the question, we carried out a study at the University of Missouri of Science andTechnology Experimental Mine in Rolla, Missouri to evaluate the three major methods in existence:traditional burden pole, laser profiling and drone photocatalysis.The traditional burden pole has the longest history in bench profiling. The method consists of a modifiedPhiladelphia surveyor's pole with a weighted tape on a pulley at the end. The method measures theprofile of a face out from the center of the borehole and down to point of the face of interest. It measures2D burden at where the pole measurement is. It can measure 2D minimum burden if the surveyor knowseach location on the face the location of minimum burden.The laser profiler has been around for four decades. The current iteration of the method consists of the3D laser scanner and a laser target. The laser target sets the area to be scanned (top, bottom, left, andright), including borehole placement. The 3D laser scanner has a laser measuring tool and a motorizedbase that scan the face only to give the blaster a map of the open face. Although named 3D, the methodnormally only scans the surface of the bench face, but not the top of the bench, because the scanner isoften placed at the foot of the bench. For this reason, it can give erroneous results due to incorrect targetplacements or complex top surface of the bench. It mostly gives out 2D burden, while 2D minimumburden calculation requires specialty software and additional blaster training.The most cutting-edge method is using a drone equipped with the 4K camera and a geotagging-GPS.This method requires only one drone operator and photogrammetry software that generates a measurablemap of the site. In this study, we used Strayos's software. The drone method offers a genuinely 2D and3D minimum burden analysis.Our study evaluates the three major methods along the dimensions of accuracy, repeatability, humanerror profile, features of the burden, and cost. In the end, we conclude that the drone method offers themost accurate and repeatable results, leaving little room for human error, all at a lower cost.