The goal of the Illinois Basin Decatur Project was to conduct a large-scale demonstration of deep saline geological storage and to validate the capacity, injectivity, and containment of the Mt. Simon sandstone. The project was supported by the U.S. Department of Energy (DE-FC26-05NT42588) and the Illinois Department of Commerce and Economic Opportunity. The MGSC partnered with Archer Daniels Midland Company (ADM) and Schlumberger Carbon Services to inject 1 million metric tons of CO2 over a three-year injection period at the ADM plant location in Decatur, Illinois. Operational injection started on November 17, 2011 and was completed successfully on November 26, 2014 with a total volume of 999,215 tonnes. An extensive Monitoring, Verification, and Accounting program has been undertaken and is focused on the 0.65 km2 (0.25 mi2) project site. This includes surface monitoring techniques such as monitoring surface deformation, soil gas sampling, and shallow groundwater sampling. Subsurface monitoring techniques used included seismic surveying, temperature and pressure monitoring, fluid monitoring, and well logging. Monitoring was initiated in 2009 and concluded in 2017 after the three-year injection and three-year post-injection periods.