At an altitude of approximately 4,000-meters, Las Bambas is a large open-pit copper mine project located in the Cotabambas province, Apurimac region of Peru. It is a polymetallic mine with significant mineral resources and copper ore reserves with an estimated life exceeding 20-years. Production at the mine was scheduled to start in 2015 following confirmation that the project had reached 80% completion by December of 2014. The first production of the final product, copper concentrate, was expected to be produced by the first quarter of 2016.
The mining process involves extracting the ore from the open-pit, transporting it by truck to the crushing plant, and then transporting the crushed ore approximately 5.2-km via (3)-high-speed conveyors to a stockpile for processing. Each of the (2)-long-distance conveyors will be powered by (2)-4,400-kW Siemens gearless drives, making these conveyors some of the most highly powered in the world. At a speed of 6.5-meters/second and a belt width of 1.830-m, the conveyor system will transport approximately 9,400-tonnes/hour of crushed ore to the stockpile for processing.
In order to create the stockpile, the discharge end of the final conveyor required design of a massive cantilevered steel structure weighing roughly 170 tonns. Based on its primary purpose of stacking crushed ore on the stockpile, this structure was dubbed “the Stacker”. As a result of its size, complexity and high seismic loading, the Stacker was the most challenging structure within the conveyor scope of work.
The contract for the supply of the overland conveying system was awarded to Thyssen Krupp Robins Inc. Much of our prior projects had been completed largely without 3D modeling software, which led to numerous design challenges, inefficiencies and delays. We chose to use Tekla Structures to improve their workflow, and with over 5-years of experience under their belt prior to Las Bambas, it was decided to design the more complicated structures with that software.
The Stacker in particular was slated to use Tekla Structures in order to ensure that all of the intricate interfaces and potential clashes were caught ahead of time. Amazingly, this 700-tonne structure had few than 20-RFI’s during the detailing and fabrication stage, all of which was completed in China. Upon arriving in the field, there were only a few wrench clearance issues that were missed by the detailer, which were easily addressed with the erection crew. Pre-assembly of the massive sections on the ground proceeded at an incredible rate, and were lifted into position without any problem.
Using Tekla Structures, we were able to eliminate redundant modeling efforts, streamline communication with the detailer/fabricator located in China and drastically reduce design discrepancies. One of the Tekla Structure tools used to expedite the shop drawing checking process was the shop drawing review tool saving many hours. We were also able to use a number of reference files from other vendors to locate equipment such as winches, pull cord switches, overhead cranes, belt scrapers, and alignment switches, these also saved time on fabrication by getting the items procured early constituted accurately designed brackets to mount these items. This led to an incredibly happy client.