GUIDELINES FOR SAMPLE COLLECTING AND ANALYTICAL METHODS USED IN THE U.S. GEOLOGICAL SURVEY FOR DETERMINING CHEMICAL COMPOSITION OF COAL

By Vernon E. Swanson and Claude Huffman, Jr.

U.S. GEOLOGICAL SURVEY CIRCULAR 735
1976

COMMENTS AND RECOMMENDATIONS

The guidelines for collecting coal samples and the analytical methods described here are those currently used by the U.S. Geological Survey. The analytical methods are periodically modified to improve efficiency and accuracy, and, as new and better methods and instruments become available, they are adopted and used. For example, new polarographic methods are now being tested for analysis of Cd and Pb in coal ash; and research continues in the application of neutron activation analysis (Millard and Swanson, 1975) and X-ray fluorescence analysis for a suite of other elements.

Similarly, the need and emphasis for data on different elements change. Thus, Cl analysis has been added to, and Te and Tl analyses have been dropped from, the list of elements included in the coal analyses routinely reported by the U.S. Geological Survey.

Copies of all analyses of coal samples are sent to the geologist who collected the samples, extra copies of the analyses are, if requested, also sent to the geologist to give to, for example, owners of property from which samples were collected.

All analyses are reported by the laboratory either as percent or as parts per million (ppm). Further, it is recommended that all analytical data, when included in the geologist's written report, should be reported as percent or parts per million:

1. Proximate and ultimate analyses and forms of sulfur analyses, in percent, on an as-received, moisture-free, and moisture- and ash-free basis.
2. Major-oxide composition of ash, in percent of ash.
3. Trace-element composition, in parts per million, as analyzed on ash of coal, or raw coal, and, when desirable, all trace elements on ash of coal may be converted to 'whole coal' on an air-dried basis.
4. Btu values (British thermal units per pound of coal) are, of course, not shown in percent or parts per million, simply as Btu/lb or Btu.

All of the locality, stratigraphic, and analytical data are stored in and are retrievable from the U.S. Geological Survey's computer system.

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