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D I G I TA L M A P P I N G Dimensions conference, Mario Glenn Nunez, project engineer for DIP Engineering, described the results of a test comparing the application of a UAS and a conventional terrestrial laser scanner to compile a DTM and calculate volume of a large, cone-shaped stockpile below the crusher discharge conveyor at an open pit mine. UAS setup, programming, placement of ground-control points, flight time and data processing for the cone measurement took just under two-and-a-half hours, according to Nunez, while sight-point selection and planning, scanning and data processing took five hours with the laser scanner system. Surface-image generation from the point clouds of the two systems shows a clear visual advantage with the UAS image, which provided details within the cone's interior spaces that could not be generated with the data collected by the laser scan. Speed and Accuracy Even with vastly quicker turnaround times for collecting and analyzing geospatial data collected by the most advanced photogrammetry and digital surface modeling solutions, a common issue for mine planners is the amount of time typically required to generate or update a pit plan. For large open-pit operations this may take weeks or more and generally requires users that have extensive training with the software system, as well as long sequences of mostly manual user input operations and time-consuming editing procedures. To reduce the time and effort needed to generate accurate, revisable mine plans, Trimble currently is in the final stages of developing a highly streamlined open-pit design package that evolved from an informal conversation between some South African mine managers and engineers about a military project aimed at reducing the time required to design and construct emergency airfields in remote locations. The Joint Rapid Airfield Construction (JRAC) program was a cooperative effort in the early 2000s by the U.S. Army Corps of Engineers and their U.S. Air Force counterparts to investigate methods for rapid construction and upgrade of airfields for tactical military operations. Although much of the program's focus was on construction and soil-stabilization techniques, one of its goals was to find ways to speed-up the design/upgrade process and develop engineering solutions that could be applied by less-than-expert personnel, often working under stressful conditions. This was the portion of the program that interested www.e-mj.com Pit-layout comparison tests between standard, conventional design software and Trimble's forthcoming Open Pit Mine Design program produced results with 99% correlation, as shown here with the conventional program's output on the left—but the design process took one-tenth the time using the Trimble product. Richard Gawthorpe, principal mining engineer at Anglo American, and colleagues at Kumba Iron Ore, a member of the Anglo American group and operator of the huge Sishen open-pit mine in Northern Cape Province, South Africa. Looking for a similar solution for pit design and optimization tasks, Anglo American engineers joined forces with a team from Trimble about one year ago to develop a rapid pit design program that would: • Reduce required design time by at least 80%. • Not require extensive training or prior experience from users. • Free-up staff with higher technical and analysis skills to perform review and optimization. In practical terms, the engineers wanted a tool that would allow mine staff to reduce the amount of time needed to update pit design for a large mine such as the Sishen pit, which measures roughly 5 x 17 km. The upgrade process for Sishen can take as long as three months, and once completed, the plan was tedious and difficult to edit. The whole process took experienced engineers and technicians away from other more productive activities—a common problem in an industry that is chronically short-staffed and increasingly dependent on less-experienced workers. To craft an effective software tool that could be easily grasped and applied by non-expert users, the development team focused on several key characteristics for the program: it must be a 'simple' solution, yet offer advanced editing capabilities; employ automated tools with controlled parameters; and require minimal training, yet provide sufficiently detailed results to allow for options analysis. The resulting program, said Gawthorpe, called simply Trimble Open Pit Mine Design, provides a 'paradigm shift' in pit design, allowing dramatic reductions in time required. In on-site comparison testing against a conventional pit design program, Gawthorpe said Open Pit Design was able to produce a finished design in about four hours, compared with 40 hours for the conventional solution—and with 99% correlation between the two designs. The development team is looking at adding several highly useful features to the existing program, said Gawthorpe. One of these would essentially reverse common design practice by using a database that contains a complete set of physical parameters for the mine's production equipment fleet; instead of arbitrarily assigning a standard haul-road width during the design process, for example, the user could simply input the truck type and the program would automatically assign road width and turn radius based on truck size. Other future features may include enabling risk-based slope optimization, geo-risk analysis and pit development strategy analysis from detailed designs. JANUARY 2013 • E&MJ; 43