Imaging Process Control for Mining and Cominution of Construction Materials
Extraterrestrial mining activities will at first be concerned with the production of construction materials. Rock and earth materials can provide the strongest and most cost effective solutions. Scarce resources (energy, human intervention) in extraterrestrial mining operations, will limit many types of activities. At the same time, construction materials need to be processed, including blasting, crushing, screening, and milling, to exact specifications. Automation is the key to minimizing resource utilization, and optical sizing is crucial for these tasks, enabling automated process control without requiring excessive human quality control strategies.
Post-Muckpile, Pre-Primary Crusher, Automated Optical Blast Fragmentation Sizing
Automated rock sizing using digital image analysis has been well established. The methods work best under the controlled conditions of a conveyor belt, where camera angles and distances are constant, lighting is controlled, and sampling errors are at a minimum. Unfortunately, in most operations by the time rock is loaded onto a conveyor belt, it has passed through a primary crusher, and the size distribution no longer reflects only the blasting process. On the other hand, imaging and measuring the size of fragmentation on muck piles, while still useful, is problematic. Results can vary because of camera distances and angles, different lighting conditions can change measurements, and most importantly, because only the surface of the muck piles can be measured, tremendous sample bias can result in large measurement errors. The solution is to image the rock while in transit between the muck pile and the primary crushing station. This includes surface and underground HD (Haul Dump) and LHD (Load Haul Dump) type vehicles, using this method results in significantly decreased sampling errors. However new technical difficulties enter into the picture, including the need for advanced triggering and vehicle tracking mechanisms.
Tracking Hardness and Size: Measuring and Monitoring ROM Ore Properties at Highland Valley Copper
Highland Valley Copper recently implemented a system of measuring run-of-mine (ROM) ore properties and monitoring their effect on both mine and mill performance. These properties are principally ore hardness and size. For some years, Highland Valley Copper has been estimating ore hardness using knowledge of the geological conditions combined with previous mill experience. These estimates assist with ore blending and forecasting. The new system outlined in this paper, is the next step in this program. Using the latest technology available in mining equipment, ore properties are tracked through the in-pit crushing, conveying and stockpile network to the mill feed using the mine dispatch system and some simple models. The result is a continuous update on the ore hardness going to all five grinding lines along with predictions for the future. This will give both operators and process control systems alike the opportunity to shift targets and/or change operating conditions to suit the ore properties. Ore size distributions from the muckpile to the mill are measured using video cameras and the WipFrag image analysis software. These measurements can provide feedback on the control of blast fragmentation as well as optimise mill throughput. For example, the effects of segregation can be minimised through the manipulation of stockpile feeders. Highland Valley Copper is in an almost unique situation of knowing the amenability of the ore they are treating through systems put in place to measure and monitor the ore properties in real-time. This information can then be used by the mine and mill engineers to improve the productivity and efficiency of their operations.