Energy Resources Program

Energy Resources Program Home

Welcome to the Energy Resources Program Website "World Coal Quality Inventory" Area...

World Coal Quality Inventory

News & Recent Publications

Tuesday, January 27, 2015

USGS Compilation of Geographic Information System (GIS) Data Representing Coal Mines and Coal-Bearing Areas in China

USGS Publication: Open-File Report 2014-1219
Geographic information system (GIS) information may facilitate energy studies, which in turn provide input for energy policy decisions. The U.S. Geological Survey (USGS) has compiled geographic information system (GIS) data representing the known coal mine locations and coal-mining areas of China as of 2001. These data are now available for download, and may be used in a GIS for a...

Wednesday, December 17, 2014

Collaborative studies for mercury characterization in coal and coal combustion products, Republic of South Africa

USGS Publication: Open-File Report 2014-1153
Mercury (Hg) analyses were obtained in USGS laboratories for 42 new samples of feed coal provided by Eskom, representing all 13 coal-fired power stations operated by Eskom in South Africa. This sampling includes results for three older power stations—Camden, Grootvlei, and Komati—returned to service starting in the late 2000s...

Friday, November 22, 2013

Petrologic and Isotopic Data from the Cretaceous (Campanian) Blackhawk Formation and Star Point Sandstone (Mesaverde Group), Wasatch Plateau, Utah

USGS Publication: Open-File Report 2013–1254
To better understand the origin and distribution of sodium in these coals, petrologic studies were undertaken within a sedimentological framework to evaluate the timing and geochemical constraints on the emplacement of sodium-bearing minerals, particularly analcime, which previously had been identified in coals in the Blackhawk Formation. 

Wednesday, December 19, 2012

Vitrinite Reflectance Data for Cretaceous Marine Shales and Coals in the Bighorn Basin, North-Central Wyoming and South-Central Montana

USGS Publication: Open-File Report 2012–1254
The purpose of this report is to present new vitrinite reflectance data collected from Cretaceous marine shales and coals in the Bighorn Basin to better characterize the thermal maturity and petroleum potential of these rocks.

Thursday, November 08, 2012

Using simulated maps to interpret the geochemistry, formation and quality of the Blue Gem Coal Bed, Kentucky, USA

Outside Publication: International Journal of Coal Geology
This study presents geostatistical simulations of coal-quality parameters, major oxides and trace metals for an area covering roughly 812 km2 of the Blue Gem coal bed in southeastern Kentucky, USA. The Blue Gem, characterized by low ash yield and low sulfur content, is an important economic resource. Past studies have characterized the Blue Gem's geochemistry, palynology and petrography and inferred a depositional setting of a planar peat deposit that transitioned to slightly domed later in its development.

Thursday, September 27, 2012

Database of the United States Coal Pellet Collection of the U.S. Geological Survey Organic Petrology Laboratory

USGS Publication: Open-File Report 2012–1151
The Organic Petrology Laboratory (OPL) of the U.S. Geological Survey (USGS) Eastern Energy Resources Science Center in Reston, Virginia, contains several thousand processed coal sample materials that were loosely organized in laboratory drawers for the past several decades. 

Friday, June 29, 2012

Geologic Framework and Petroleum Geology of the Bohaiwan Basin Province, China

Includes the Shahejie−Shahejie/Guantao/Wumishan and Carboniferous/Permian Coal−Paleozoic Total Petroleum Systems

USGS Publication: Scientific Investigations Report 2011–5010
This report discusses the geologic framework and petroleum geology used to assess undiscovered petroleum resources in the Bohaiwan basin province for the 2000 World Energy Assessment Project of the U.S. Geological Survey. The Bohaiwan basin in northeastern China is the largest petroleum-producing region in China.

Tuesday, May 01, 2012

Minor element distribution in iron disulfides in coal

A geochemical review

Outside Publication: International Journal of Coal Geology
Electron beam microanalysis of coal samples in U.S. Geological Survey labs confirms that arsenic is the most abundant minor constituent in iron disulfides in coal and that selenium, nickel, and other minor constituents are present less commonly and at lower concentrations than those for arsenic.

Sunday, January 22, 2012

Shallow Coal Exploration Drill-Hole Data

Alabama, Georgia, Kentucky, Louisiana, Mississippi, Missouri, North Carolina, South Carolina, Tennessee, and Texas

USGS Publication: Open-File Report 2011–1261
Coal exploration drill-hole data from over 24,000 wells in 10 States are discussed by State in the chapters of this report, and the data are provided in an accompanying spreadsheet.




The U.S. Geological Survey (USGS) Energy Resources Program, in cooperation with many agencies and scientists from the world’s coal producing countries, undertook a project, called the World Coal Quality Inventory (WoCQI), to obtain samples of coal from the world’s producing coal mines during a limited period of time (roughly 1995-2006). The resulting WoCQI database is intended to help policy makers with decisions regarding:

  • Domestic coal resource allocation
  • Import needs and export opportunities
  • Foreign policy objectives
  • Technology transfer policies
  • Foreign investment prospects
  • Environmental and health assessments
  • Byproduct use and disposal

This can contribute to the most economically and environmentally efficient global use of coal.


International collaborators were provided sample collecting guidelines and forwarded their samples to the U.S. Geological Survey (USGS). Samples were subsequently analyzed for major-, minor-, and trace-elements at the USGS Inorganic Geochemistry Laboratory located in Denver, CO and for proximate and ultimate analyses at a commercial laboratory located in Pennsylvania using ASTM methods (2007). The resulting dataset, in EXCEL 2003 format, includes samples from 56 countries and is not subject to the inter-laboratory variability present in many coal chemistry compilations.


Not all global coal resource occurrences are included in the WoCQI, but 1,580 individual coal samples were eventually collected for analysis. About 70 percent of the WoCQI samples have data from the commercial laboratory, which are presented on an as-received basis. Values for nearly 50 elements from the USGS laboratory were calculated to a consistent dry, whole-coal basis in the dataset.

The WoCQI database is a unique compilation of coal chemical data and in some cases, the WoCQI data may be the only data available for public use. Care must be used when selecting the sample data for use in statistics or interpretation for the following reasons:

1) There are single samples with little or no spatial variability
2) There is a mix of sample types and collection methods
3) The accuracy of the USGS Inorganic Geochemistry Laboratory major-, minor-, and trace-element data is variable

Additional WoCQI Information

Five newsletters (see archive) were published during the sample collection phase to keep communications open between international collaborators and the USGS. For samples from South American countries, the USGS published an open-file report in 2006 (Karlsen and others, 2006) and the Indonesian samples in 2007 (Belkin and Tewalt, 2007). Although no Geographic Information System (GIS) files are part of the WoCQI, two publications containing international coal-bearing areas have been produced and can be used in conjunction with the WoCQI chemistry data (western hemisphere: Tewalt and others, 2008 ; Africa: Merrill and Tewalt, 2008). Ongoing coal-related international studies relate to the creation of GIS shape files for coal-bearing areas of the world. Please check the News tab for the most recent releases.


Belkin, H.E., and Tewalt, S.J., 2007, Geochemistry of selected coal samples from Sumatra, Kalimantan, Sulawesi, and Papua, Indonesia: U.S. Geological Survey Open-File Report 2207-1202, available online at

Karlsen, A.W., Tewalt, S.J., Bragg, L.J., and Finkelman, R.B., eds., 2006, The World Coal Quality Inventory: South America: U.S. Geological Survey Open-File Report 2006-1241, available online at

Merril, M.D., and Tewalt, S.J., 2008, GIS Representation of Coal-Bearing Areas in Africa: U.S. Geological Survey Open-File Report 2008-1258, available online at

Tewalt, S.J., Kinney, S.A, and Merrill, M.D., 2008, GIS Representation of Coal-Bearing Areas in North, Central, and South America: U.S. Geological Survey Open-File Report 2008-1257, available online at

Harvey Belkin
Lead Scientist

Top of Page


Currently Available WoCQI Data Downloads:

World Coal Quality Inventory Spatial Viewer  

World Coal Quality Inventory (WoCQI) Spatial Viewer:
This viewer allows users to select a country and download underlying data associated with countries that were working collaboratively to sample and inventory coal.

Download All Chemical Data:
Chemical Analyses in the World Coal Quality Inventory, Version 1:
Open-File Report 2010-1196

Additional International Chemical Data [.xls]

Metadata for Additional International Chemical Data [.txt]

Petrographic analyses and selected photomicrographs of WoCQI samples -- Read Me [.docx]

Selected photomicrographs provided by University of Kentucky Center for Applied Energy Research -- Appendix A [.pdf]

Petrographic analyses in spreadsheet format provided by University of Kentucky Center for Applied Energy Research -- Appendix B [.xls]


Page Last Modified: Wednesday, December 03, 2014


Publications Database
Publications & Advanced Search
A searchable database of thousands of published sources, dating back several decades
USGS Energy Data Finder
Find Data
USGS Energy Data Finder:  Download GIS and tabular data, databases, geospatial web services (ArcGIS, WMS, KML)
A single map viewer portal incorporating a range of maps, data and services
National Coal Resources Data System
National Coal Resources Data System
USGS coal resources databases of national scope