Modern and contemporary geological research progress and trends of minerals in coal measures of China

Background Coal measures minerals (CMMs) are an important guarantee for the security of mineral resource supply in China. Reviews for the progress and trends of geological research on CMMs of China has both historical significance and practical value, and may also provide enlightenment for future research.Advances By verifying historical facts and sorting out the logical relationship, the progress is condensed into five aspects. One is that the theoretical system of CMMs geology is becoming increasingly perfect. The classic system of coal geology theory in China was formed in the second half of the 20th century, and since the beginning of the 21st century, the theoretical system of CMMs geology, mainly composed of coal, coal measures gas and key metals, has gradually formed. Secondly, the understanding on the origin and genesis of coal has promoted the development of international coal geology, with discovering the world's youngest soft brown coal, revealing the coalification jumps during late coalification stage, proposing the new theory of coal metamorphism, establishing a branch discipline of ordinary organic petrology, and comprehensively revealing the formation and evolution mechanism of coal. Thirdly, the ore-forming theory of CMMs resource accumulation and occurrence has unique characteristics. Multiple sedimentary and structural coal-controlling models have been established, and the basic pattern of coal accumulation in the China’s sea area has been identified. Multiple types of key metal deposits in coal measures have been discovered, and the zoning schemes for coal-controlling tectonics and key metal mineralization zones in coal measures has been proposed, and a theoretical system of coalbed methane geology has been formed. Fourthly, significant achievements have been made in the geological survey and evaluation of special coal resources. The geological prediction and evaluation method systems for special coal types, environmentally friendly and clean coal resources have been established, as well as the evaluation method systems for the potential of oil-rich coal and underground coal gasification resources. Preliminary investigations have been conducted on the coal resources for related purposes. It is considered that major national demands determine the direction of geological research on CMMs resources. Prospects TTherefore, It is suggested that future geological research focus on four directions, including the precise exploration and development of coal resources, exploration and orderly development of coal measures gas, exploration and development of key metal minerals, and geological support for fluidized in-suit mining of coal. At the same time, attention should also be paid to exploring the mechanism of helium enrichment in coal measures and researching resource prediction methods.