Engineering & Mining Journal

OCT 2017

Engineering and Mining Journal - Whether the market is copper, gold, nickel, iron ore, lead/zinc, PGM, diamonds or other commodities, E&MJ takes the lead in projecting trends, following development and reporting on the most efficient operating pr

Issue link: https://emj.epubxp.com/i/887604

Contents of this Issue

Navigation

Page 69 of 83

68 E&MJ; • OCTOBER 2017 www.e-mj.com OPERATING STRATEGIES In today's competitive commodities environment, mining com- panies need to accurately know the extent of their remaining resources, how much is being produced in a defi ned period, and how much is stockpiled and available for sale. Traditionally, mine-site information is gathered using ground- based survey techniques. While highly accurate, the process has several drawbacks: it often requires trained staff to be on-site in remote locations; coverage of large mining areas is tedious and time consuming; and the high cost of a ground-based survey limits the refresh cycle. Satellite imaging is fast, safe and cost-effective, especially when dealing with large undertakings. The technology has been successfully implemented in a wide range of sectors, from plan- ning oil pipelines to monitoring the construction of hydroelectric dams. Regardless of the remoteness or size of a project, engi- neers and operators fi nd satellite imaging data valuable, timely and precise. Satellite measurement is ideal for a variety of ap- plications, including construction, environmental and surveying. Airbus' Pléiades constellation consists of two satellites: Pléia- des-HR 1A and Pléiades-HR 1B. They offer up to daily revisit capability over any point on the globe, delivering fi ne detail. Proving the Value To substantiate the value of satellite imaging for the mining sector, a service provider must confi rm that its information-gath- ering and interpretation process has suffi cient accuracy. It needs to conduct controlled tests under a number of different real-life scenarios. Airbus contracted with an open-pit mine operator to evaluate its Stack Insight volume modeling service. Using very high reso- lution 50-cm imagery products acquired in stereo by its optical Pléiades satellites, Airbus automatically generated volume cal- culations using Stack Insight. At the same time, ground surveyors gathered information using LiDAR. The survey team collected data at various areas (including fl at, mining and combinations thereof), as well as heaps and pits of varying sizes. In this specifi c example, when Stack Insight volumes were compared to LiDAR measurements, accuracy assessment was found to be within 0.04%-1.77% difference rate. When elevation accuracy was measured using statistical comparison, the standard deviation of the difference in elevation between Stack Insight and LiDAR data was found to be between 22-56 cm. 1 Meeting the Challenge Kumba Iron Ore, a subsidiary of Anglo American, operates the Sishen mine in South Africa. The operation is a big open- pit mine, extending over 100 km 2 . The size of the operation made daily decision-making a major challenge for the oper- ator. Survey crews were kept constantly busy creating data that could be used to make blasting and excavation decisions, move strategic equipment and quantify materials — all in a timely fashion. Kumba Iron Ore contracted with Airbus and Pinkmatter Solutions (a South Africa-based specialist in geo-information software design and satellite image processing), to produce a weekly update of operations on the mine. Under the contract, Airbus collects images and Pinkmatter Solutions automatically ortho-rectifi es the imagery using custom high-precision Ground Control Points (GCPs). After processing, Kumba uses the resul- Calculating Mine-site Volumes From Space Satellite imaging provides a safe, fast and cost-effective alternative to ground-based open-pit mining surveys By Chloé Leclerc Satellite images captured at two different dates: the fi rst one was captured on September 24 and the second one was captured on October 13, showing how mining activities have moved ground in the timespan. The pit has been excavat- ed between the two dates. This is then used for the change detection calculations. 1 The accuracy of satellite-date elevation modeling is highly dependent on the quality of ground-truthing performed (GCPs, reference imagery, etc). Homogenous areas with few recognizable features, such as snow-covered areas, may be inaccurate. Imagery of areas with dense vegetation cover will not accurately represent the underlying surface area.

Articles in this issue

Links on this page

Archives of this issue

view archives of Engineering & Mining Journal - OCT 2017