CHEMISTRY OF COAL SAMPLES FROM THE GULF COAST PROVINCE OF TEXAS AND LOUISIANA

摘要

The National Coal Resource Assessment is a comprehensive study conducted by the U.S.Geological Survey (USGS) of the coal resources in major coal regions of the United States. Theobjectives of this assessment are to provide digital information on the location, quality, andquantity of coal that is expected to be mined during the next several decades. Emphasis is beingplaced on the distribution of the three environmentally sensitive trace elements mercury, arsenic,and selenium. The qualities of the coal from mines of the Wilcox Group (Paleocene – Eocene)are compared. For the purpose of this report, the Gulf Coast Province was divided into fourassessment areas: (1) the Sabine Uplift – Louisiana, (2) the Sabine Uplift - Texas, (3) NortheastTexas, and (4) Central Texas. These study areas were chosen because they are sites of current orfuture coal mining and there are sufficient stratigraphic and coal quality data for assessment.Coal quality data in each study area were based on both public and confidential records frommore than 600 drillholes and/or measured sections from surface mines for the Gulf CoastProvince. For each sample location, thickness-weighted averages for proximate, ultimate, andtrace element data were calculated in order to generate statistic means for each study area. Coalquality parameters vary little between the study areas. Mineable coal in the Gulf Coast Provincehave medium ash yields (10.0 – 16.4 %, as-received basis), low total sulfur contents (0.5 – 1.2%, as-received basis) and very low calorific values (6100 to 7200 Btu/lb, as-received basis).Mercury and arsenic values are well within the ranges of other coals in the United States.Selenium however seems to be concentrated in some of the Texas coals with maximum valuesreaching 32.8 ppm.