Study on optical fabric of coal and its geological indications

ABSTRACT

In order to study the optical fabric of different coals and the geological information it reflects, the optical characteristics and their differences of different coal samples with coal texture are analyzed, and the relationship between the vitrinite maximum reflectance and the characteristics of tectonic stress is studied. The results show that the coal samples with primary texture show the uniaxial negative photometry in the low and medium coal rank stage, and change to the biaxial negative photometry in the anthracite stage. The optical anisotropy of coal increases with the increase of coal grade. Tectonic coal is characterized by the biaxial negative photometry in the stage of fat coal due to the complex tectonic stress. Combined with the result analysis of Ferrin diagram, it is discovered that the cataclastic structure coal in Huainan mining area mainly suffered from the compressive stress of Indosinian movement, while the granular structure coal mainly experienced the compressive stress of Yanshan movement and Himalayan movement.

KEYWORDS:

• Coal
• optical fabric
• vitrinite group
• reflectance
• tectonic stress

Additional information

Funding

This work was supported by the funding from the topics of National Key Research Programs of China (Grant No.2018YFF0213801) and the Science and Technology Innovation Special Project of Tiandi Science and Technology Co., Ltd. in China (Grant No. 2018-TD-MS067).

Notes on contributors

Wenping Jiang

Wenping Jiang was granted Ph.D. degree by China Coal Research Institute (CCRI) in Beijing in 2012. She is now the professor of Xi'an Research Institute of China Coal Technology & Engineering Group Corp. Her research interest mainly includes coal geology, coalbed methane geology and development, etc.

Xiaozhong Song

Xiaozhong Song is now the associate professor of Xi'an Research Institute of China Coal Technology & Engineering Group Corp. His research interest mainly includes coal geology and coal petrology, etc.

Lingwen Zhong

Lingwen Zhong is now the professor of Xi'an Research Institute of China Coal Technology & Engineering Group Corp. Her research interest mainly includes coal geology and coal petrology, etc.