ISGS - July 2011 Activity Highlights

An Illinois quarry mining high-calcium limestone
used by coal-fired power plants to remove sulfur

Characterizing High-Quality Illinois Limestone

Illinois State Geological Survey geologist Zak Lasemi submitted the final technical report to the Illinois Clean Coal Institute for a project dealing with the characterization of high-calcium limestone for flue-gas desulfurization near Illinois coal-fired power plants. Illinois is experiencing increased demand for high-calcium limestone for flue-gas desulfurization. High-calcium (CaCO₃) limestone is not widely present in Illinois, however, and most limestone quarries consist of multiple layers or ledges whose CaCO₃ content and quality vary significantly. The project study compiled and updated geologic maps showing the location of high-calcium limestone resources. The study also conducted a layer-by-layer examination of selected limestone quarries in order to identify and characterize the high-calcium limestone zones, especially those with CaCO₃ contents of 95% or more. More than 600 samples were analyzed for mineralogical and chemical content. The results show that high-purity limestone (>95% CaCO₃) in Illinois is mostly confined to rocks that are older than the Pennsylvanian System and are at or near the surface in western and southern Illinois, especially near the Mississippi and Ohio Rivers. Very little high-calcium limestone is found in the northern part of the state where the dolomite of the Ordovician and Silurian Systems predominate. This study provides a valuable database for the location and properties of high-calcium Illinois limestone needed for flue-gas desulfurization. (Contact: Zak Lasemi)

Gift of Gas Storage Field Data

Ed Mehnert, Illinois State Geological Survey geologist, received four boxes of geological, geochemical, and geophysical data from Karen Benson, Vice President of Operations Services and Underground Storage, Southern Pipeline Group. The data were collected from 26 boreholes completed in the Trenton limestone and Mt. Simon Sandstone at the Tuscola natural gas field (Champaign and Douglas counties), which ceased operations in the 1990s. The data include an aquifer test, core descriptions, laboratory core tests (porosity and permeability), borehole logs, and water quality. These data will be very valuable for our efforts to understand geologic carbon sequestration in the Mt. Simon Sandstone. Mehnert is extremely grateful to Karen Benson and her company for locating and donating these geologic records, which were preseumably lost after the Tuscola natural gas storage field ceased operations. (Contact: Ed Mehnert)

Highlights Archive

Updated 08/06/2012 SLD