the possibility of material blending can be explored for multi-category material analysis. One final point of interest is the Parking Lot, a designated area for the trucks to stay during shift change for all cases. The mine is interconnected by two-way haul roads. Figure 60 – Diagram of the open pit copper mine. Additional information for the processing facility includes a target capacity of 25,000 tons/shift, with an upper cap of 30,000 tons/shift and a variable lower cap (subject to relaxation to prevent unbounded solutions) but expected to be 20,000 tons/shift. The installed recovery rate is 80% for a target grade of 0.3400 %Cu, with an upper bound of 0.3900 %Cu and lower bound of 0.3100 %Cu. The production schedule of the mine is set to 10 hr/shift, 2 shifts/day for 300 days/year of continuous operation. Regarding the equipment, two shovels are allocated to the working zone (25-cyd & 32cyd) located together in a recently depleted muck pile and ready for new allocations. Given the geometry restrictions of the pit, only one shovel can be allocated to a muck pile at the same time. The first task for the model is to assign a new allocation for both shovels before starting the truck fleet movement. Shovel travelling times are independent for each shovel towards and between muck piles. On the other hand, the truck fleet is composed of (12) twelve 150-ton and (8) eight 200-ton trucks. Although each truck is unique in terms of mechanical availability and performance, the case study considers them as similar, binned by capacity difference only. This decision is made intentionally to ease the analysis of the uncertainty factor focused on the geologic risk (grade); this way, there would be no biased allocation of resources by best performance, only by available capacity. Loading times are precalculated based on averages from truck-shovel matching for each truck to generate a single value by truck capacity. Similar calculations are applied to dumping time at each destination. Loaded and empty travelling, as well as returning to parking lot times are calculated independently for each truck using a flat travel speed and distances from each muck pile to each destination. Further information on the shovels & trucks’ operational parameters and the economics of the mine can be requested privately through the authors’ contact information provided. 3.2.Simulation of Uncertainty Parameters
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