Coal Quality

Mercury in Coal - Geoscientists are working on ways to better understand the distribution of mercury in coal and to potentially reduce mercury in emissions by means of coal preparation. This work builds on previous USGS projects and results obtained from Department of Energy (DOE)-funded collaborative multi-element studies completed nearly a decade ago. Geologists are refining the USGS selective leaching procedure for mercury in coal to optimize mercury mode-of-occurrence determinations. This capability is especially important for coals with ordinary mercury contents because other methods are limited to unusually mercury-rich coals. Geologists are conducting research to optimize micro- or nano-scale approaches to study the distribution of mercury in coal and other solid fuels.

Coal and Coal Combustion Products - Geoscientists at the USGS are completing research designed to quantify and model the elements and compounds in coal and coal combustion products (CCPs) through the coal utilization cycle. Coal quality studies tend to concentrate on single parameters, for example, arsenic or mercury. In contrast, this work takes a comprehensive "cradle-to-grave" approach. The research focuses not only on the occurrence and formation of different elements and compounds throughout the spectrum of mining, production, and transportation, but most importantly, on the utilization and the disposal of CCPs. The cradle-to-grave approach allows us to link in-ground coal quality trends to CCPs, a critical step in predicting environmental effects of coal utilization.

A variety of coal quality parameters including sulfur; major, minor, and trace elements; and coal mineralogy were examined from pulverized-coal power plants in the United States. Five pulverized-coal-fired power plants that utilize different designs and pollution-control devices were sampled in Alaska, Indiana, New Mexico, Ohio, and Wyoming. Two of the power plants receive coal from a single coal bed or coal zone: the Ohio power plant utilizes Upper Pennsylvanian Pittsburgh coal, and the Wyoming plant utilizes Tertiary Tongue River Member of Fort Union Wyodak-Anderson coal from the Powder River Basin. The remaining three power plants receive coal from two to three coal beds or coal zones: the Alaska power plant utilizes beds 3, 4, and 6 from the Middle Miocene Nenana Coal Province; the New Mexico plant is supplied by three unnamed coal beds from the Upper Cretaceous Fruitland Formation coal of the San Juan basin; and the Indiana power plant utilizes Pennsylvanian Stockton coal and an unnamed coal bed from the Illinois Basin. Samples were collected over multiple weeks to ensure that samples of feed coal and CCPs were representative.

Pores in Gas Shales - USGS scientists are collaborating with geoscientists at the Commonwealth Scientific and Industrial Research Organization (CSIRO), Sydney, Australia, and Griffith University, Brisbane, Australia, to examine pores size distribution and connectivity in shale gas using the ultra-high-resolution small-angle neutron scattering (USANS) diffractometer at the National Institute of Standards and Technology (NIST) and the General Purpose Small Angle Neutron Scattering (GP-SANS) diffractometer at DOE’s Oak Ridge National Laboratory (ORNL).

Co-fired Biomass and Coal Studies - USGS scientists are collaborating with geoscientists and engineers at the University of Kentucky Center for Applied Energy Research and East Kentucky Power Cooperative to sample a power plant that has test burns of switchgrass and coal to study the impact of biomass blending on boiler operation and the composition of combustion products.

World Coal Maps - With the increased emphasis on coal usage throughout the world, knowledge of coal resources and reserves, and associated quality and mineability is essential for government and industry planners and policy and decision makers. However, digital data of world coal occurrence are not readily available. USGS has produced geographic information system (GIS) and coal quality data of the coal-bearing areas of the Western Hemisphere and Africa based on existing USGS surficial geology coverages published in Digital Data or Open-File series. However, much of the world’s coal resources occur in the Eastern Hemisphere and a representation of their occurrence and available analytical data needs to be compiled. In 2011, USGS is compiling two new Eastern Hemisphere world coal maps of 1) Pakistan and 2) India and Bangladesh. Additional country maps will be produced in the future.

Data Quality - USGS chemists are providing quality assurance (QA) and quality control (QC) of geochemical analyses to geologists and other geoscientists. Chemists works with geoscientists prior to sample collection and sample submittal to ensure that the correct analyses are selected, that sufficient sample has been collected, and that an adequate number of duplicates, blanks, and QA/QC samples will be submitted to USGS and commercial laboratories.