Energy Resources Program

Energy Resources Program Home

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

World Coal Quality Inventory


Article Thumbnail Image 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...
Friday, June 29, 2012  Type: Publication

Article Thumbnail Image Geographic information system (GIS) information may facilitate energy studies, which in turn provide input for energy policy decisions. Prior to this study, no GIS file representing the occurrence of coal-bearing units in India or Bangladesh was known to exist. This Open-File Report contains...
Tuesday, January 10, 2012  Type: Publication

Article Thumbnail Image Geochemistry is a constantly expanding science. More and more, scientists are employing geochemical tools to help answer questions about the Earth and earth system processes. Scientists may assume that the responsibility of examining and assessing the quality of the geochemical data they generate is...
Tuesday, September 13, 2011  Type: Publication

Article Thumbnail Image The tool of measuring "vitrinite reflectance" under a microscope has great value in petroleum exploration and coal utilization, and the reflectance is a simple number, such as 1.4% Ro, with some slight variations depending on technique. Sample collection, preparation and measurement are simple...
Wednesday, August 31, 2011  Type: Outside Publication

Article Thumbnail Image The main objective of the World Coal Quality Inventory (WoCQI) was to collect and analyze a global set of samples of mined coal during a time period from about 1995 to 2006 (Finkelman and Lovern, 2001). Coal samples were collected by foreign collaborators and submitted to country specialists in...
Tuesday, September 07, 2010  Type: Publication



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: Friday, January 31, 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