Solar Sources is a privately owned company that has been mining in southwest Indiana, in the United States, for over 35 years. It focuses on safe and efficient coal production, primarily through surface mining. Felson Bowman began Solar Sources in 1974 with a small mine and a handful of employees. Today, he is still president of what is the largest independent mining company in Indiana.
Solar Sources operates four multiple-seam surface mines in southwest Indiana.
Each mine has coal seams of widely varying quality. The primary customers are the Duke Energy, AES, and Hoosier Energy generating stations that supply most of the power to the State of Indiana and its largest city, Indianapolis. Each customer requires coal with specific sulfur, ash, BTU, and moisture content. To meet the specifications, Solar Sources uses its coal-testing laboratory, heavy media coal washing plant, and blending facilities to clean and blend the multiple-seam coals.
SURFACE MINING PROCESS
Surface mining is a machine-intensive process used when seams of coal are found near the surface of the land. Several seams are often layered under the surface at depths of 10 to 80 metres (or 30 to 250 feet). The first step is to expose the coal by carefully removing the top soil and the hard overburden (soil and rock) that lies on top of the coal. The coal is then broken down into pieces of a manageable size and transported to a coal yard for testing. Coal from each seam is weighed and stored separately. Once all the coal has been removed from a section of the mine, the overburden is put back into place. Finally, the top soil is replaced and the land goes through a reclamation process.
Most of the land that Solar Sources mines is leased from farmers. As a specialist in land reclamation, the company exceeds government requirements and vows to leave the land in better condition than before mining began. Solar Sources manages farming operations for land that is going through the reclamation process. After farming the land successfully for several years to ensure its viability, the company returns the land to the original owners.
IMPROVING PRODUCTIVITY
As a veteran of the mining industry, Solar Sources focuses on efficiency and continuous improvement. At its mine in Cannelburg, Indiana, the company relied on contractors to haul the coal from the mining site to the coal yard where it is staged for testing and blending. The contract trucks were limited to hauling 25 tonne loads, and the availability of the trucks was never guaranteed. Solar Sources determined that productivity could be improved significantly by purchasing its own larger trucks. This would allow the company to haul more coal each trip and ensure that vehicles were available when needed.
In 2008, Solar Sources purchased six new Caterpillar 770 trucks for the Cannelburg mine. These off-road vehicles typically haul 40 tonnes of coal, a 60 per cent improvement over the contract trucks that had been used. Each truckload of coal that is delivered to the coal yard must be weighed to track inventory and mine output. Because the new trucks were too heavy and wide for the existing truck scale, Solar Sources turned to Premier Scales & Systems for the best off-road truck scale on the market, a Mettler Toledo model 7566 with a rated capacity of 250 tonnes. Solar Sources is now able to weigh the massive Caterpillar trucks, increasing the productivity of its operation. Today, the Cannelburg mine weighs about 5000 tonnes of coal per day across the new Mettler Toledo truck scale.
THE POWERCELL ADVANTAGE
Traditional analogue truck scales rarely report the exact weight of a vehicle because it is difficult and time consuming to calibrate them to less than 10 kilograms of error. After calibration, the analogue resistor network is easily influenced by environmental factors such as temperature and humidity. A scale with 20 kilograms of error operates well within legal weights and measures metrology limits. However, if the weight of each coal truck is understated by a mere 20 kilograms, the annual weighing error for 120 trucks per day would be about $US25,000. Businesses cannot afford to have that level of uncertainty from a truck scale.
Solar Sources? new model 7566 truck scale uses Powercell MTX load cells. Powercell load cells have proven to be very accurate and very reliable. Each Powercell load cell uses digital signal processing to calculate weight and adjust it for external influences before transmitting the values to the scale terminal, ensuring that Mettler Toledo customers receive an honest and accurate transaction for each truck weighed.
The new Mettler Toledo truck scale provided the benefit of StrikeShield lightning protection. Over the years, Solar Sources had experienced first hand how lightning could disable its analogue truck scales. Lightning strikes had shut down the company?s scales, costing days of lost productivity and requiring the replacement of destroyed components. Each incident cost the company thousands of dollars and required the scale to be recertified. The StrikeShield lightning protection system assures Solar Sources that its scales will keep working through the worst storms.
UNMATCHED VALUE
A certified Mettler Toledo distributor, Premier Scales & Systems has worked with Solar Sources for many years. To keep the vehicle scales at the mining facilities operating reliably, the distributor provides preventative maintenance and calibration services. Quality products from Mettler Toledo and excellent service from Premier Scales & Systems ensure that Solar Sources? operations will continue to run efficiently.
Source: Mettler Toledo
.jpg){kind=small}
