March 13, 2023

Survey Project Spotlight: CenterPoint Coal Pile Inventory Surveys

Every year, Lochmueller Group’s Surveying Department performs coal pile inventory surveys for CenterPoint Energy at both A.B. Brown and Culley Generating Stations in Southwest Indiana. Why you may ask? It is required that the coal piles be measured annually as an accounting audit process for the energy company. Per Department of Energy requirements, a certain amount of coal must be on hand at all times.

coal pile in•ven•tor•y sur•vey•ing (verb) – calculating the total volume and tonnage of a site’s existing coal piles; testing to analyze the moisture, ash, sulfur, and British thermal unit (BTU) content of each coal pile.

To collect data, Lochmueller utilizes conventional ground surveying methods in conjunction with unmanned aerial system reality capture data collection to create a dense point cloud to generate a contoured surface model from which the volumetric measurements are derived. This creates a much safer and cost-effective method to collect the necessary field data and provides a much more robust data set when compared to traditional ground surveying methods.

re•al•i•ty cap•ture (noun) – the use of various technical means to capture a digital three-dimensional model representation of a subject from the real world.

Thanks to the advancement of technology, our Surveying Department methods have transformed a lot over the years. Prior to 2016, the team used conventional “boots on the ground” survey methods to measure the coal piles, which involved walking up and down the coal pile. This method was time intensive and exposed team members to safety hazards. Technological advancements in affordable consumer small unmanned aircraft system (sUAS) systems, i.e., drones, led our team to measure the coal piles using photogrammetry methods.

pho•to•gram•me•try (noun) – the science of obtaining information about physical objects and the environment via recording, measuring, and interpreting photographic images and patterns of electromagnetic radiant imagery and other phenomena.

Photogrammetry methods allowed our Surveying team to flyover the coal piles with the sUAS in a grid pattern, collecting hundreds of high-resolution true-scale photographs matching the project coordinate system that were then downloaded into our photogrammetry software to create a geo-referenced point cloud of the coal pile. This point cloud was imported into CAD software and processed to create a contoured surface model to compare to a base surface provided by the plant and perform volumetric calculations.

point cloud (noun) – a discrete set of data points in space that represents a three-dimensional shape or object; a model of reality related to a specific place as given by their coordinates and the specification of the used coordinate system.

The new method requires only a couple of hours’ time to setup, fly the mission, and download the photographs versus the older method which required one to two full days of work for the team. Also, the newer method provides a much more robust data set with millions of data points being collected rather than hundreds of points being collected when using the older conventional ground survey method, resulting in a more accurate volume calculation.

To learn more about our Surveying services, visit our website.

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