Aggregates Manager Digital Magazine
Issue link: http://read.dmtmag.com/i/452309
Asset Management OPERAT Asset F or both accounting and production purposes, it is critical that aggregate pro- ducers know the inventory in their stockpiles. But because inven- tories can fl uctuate with production and sales, the need for a cost-effec- tive and accurate method to measure stockpiles of stone and sand has given rise to new technology. "Producers have to have an accu- rate idea of their inventories so they can calculate production needs, and also keep accurate accounting," says Lewis Graham, president and CTO of GeoCue Group of Huntsville, Ala. "Es- pecially with a publicly traded com- pany, accounting is crucial, so there is a legal driver for precise stockpile measurement." In the past, producers often would hire surveyors to take measurements and calculate the stockpile volumes. The process is costly and can take up to two weeks or more to receive results — which may very well be outdated at that point. "That method requires a great amount of data to be taken manually to compute the volume," notes Dave Henderson, director of Geospatial Solutions for Topcon Positioning Sys- tems, Inc. "With the advent of GPS, it became a little easier. But there is up to a 15 percent difference between data collected via mobile mapping and discrete data collection. If you're paying taxes on the material, and you don't have an accurate volume, you usually end up paying more than necessary." Mobile 3D mapping employs truck-mounted automated sensors, using LIDAR (the term blends "light" and "radar"), cameras, and GPS. Data is collected as the truck drives 360° around the stockpile, and stored on an onboard computer. The data is processed at the offi ce to calculate 3D positions. Commercial off-the-shelf software, such as Virtual Geomatics or Autodesk AutoCAD Civil 3D, is used to calculate volumes. The system is a viable option for companies that produce material and also contract for earthmoving or highway and bridge construction, because it can easily make calculations over large areas. Taking to the air, manned aerial surveys can provide accurate data, but at up to $2,500 per fl ight, the frequency with which most produc- ers can take measurements this way is drastically reduced. "Most quarry managers would like to take inventory monthly. At that rate, manned aerial survey services could cost $30,000 for the year," Graham says. A new option that is being tested in the United States and is already put to use in Canada is that of the small, unmanned aerial vehicle (sUAV) or system (sUAS). "UAVs offer an oppor- tunity to quickly get an accurate data set at an affordable price," says Alex Pearson, owner of AG UAV, based in Toronto, Ontario. An sUAV consists of a small fi xed- wing airplane or helicopter that runs autonomously and is monitored remotely. Outfi tted with a camera that can take photos with ground resolu- tions as small as 3/4 of an inch, the small aerial vehicles provide a com- paratively inexpensive option for tak- ing accurate stockpile measurements. AGGREGATES MANAGER In the process of stockpile inventory valuation, aggre- gate producers have conventionally had to rely on ex- pensive or less-than-accurate means of measurement. At the most basic — and least accurate — level, produc- ers estimate production from equipment specifi cations and settings. Others have used truck scales to measure rock coming out of the pit, calculating product volume from that. Manned aerial surveys are accurate and costly. More recently, small unmanned aerial systems (sUAS), sometimes called small, unmanned aerial vehicles (sUAV), have trumped manned aerial surveying and mobile mapping. Small, remote-controlled airplanes or helicopters can safely, cost-effectively, and quickly take the thousands of images required to generate a 3D picture via software. 1 Guessing game 4 sUAS offers alternatives