Coal Resources and Depositional Setting of the Thar Coal Field, Sindh Province, Pakistan; South Asia's Newest and Largest Coal Discovery

James E. Fassett

"The U.S. Geological Survey and the Geological Survey of Pakistan, under the auspices of USAID, have recently confirmed the discovery of a giant coal field in the Thar Desert of southeast Sindh Province, Pakistan." Thus a March 1993 press release heralded the discovery of the Thar coal field. Subsequent test drilling (completed in December 1993) revealed that the huge, north-trending field is 115 km long by 40 wide, covers an area of 4,500 km², and contains almost 80 billion metric tons of coal. This discovery has increased Pakistan's known coal resources from 9 billion to nearly 90 billion metric tons and has vaulted it into 11th place in a list of the world's major coal-bearing countries.

Thar coal is low sulfur, low ash, and is lignite A in rank. As-received values for all analyzed samples are 5,333 Btu, 1.6% sulfur, 8.8% ash, 48.6% moisture, and 58.7% volatile matter. Thicker coals tend to have lower ash and sulfur values; the thickest coal bench in the field (19.6 m thick) averages .8% sulfur and 6.2% ash. Dry and ash-free heating values average, 12,322 Btu; moist and mineral-matter-free heating values are 5,747 Btu. Coal beds are thickest in the south (to 27-m thick); the 1,450-km² area within the 18-m total-coal isopach contains more than 45 billion metric tons of coal. Coal depths range from 123 m to 263 m; thicker coals in the south are the shallowest. Thar coals were deposited in late Paleocene to early Eocene backshore, north-trending bogs on the ea tern margin of a transgressing seaway. The relatively low ash and low sulfur values, especially for the thickest coals, indicate a domed-peat-bog environment of deposition.

AAPG Search and Discovery Article #91020©1995 AAPG Annual Convention, Houston, Texas, May 5-8, 1995