During the Devonian period 400 million to 360 million years ago, northern Shaanxi was a lake and sea swamp with dense plants, swarms of animals, and a warm and humid climate. Later, as the earth's crust continued to sink, the trees were quickly buried by the sedimentary mud and sand. , and then gradually formed coal-bearing rock series.
Figure 1, Shaanxi’s location in the Ordos Basin
Since then, the northern Shaanxi coalfield (mainly refers to coal distributed in Yulin City, Shaanxi Province and Zichang County, Yan’an City) has experienced three times of coal accumulation, forming three different geological eras coal fields.
Figure 2. Coal mining
Carboniferous Permian coal in northern Shaanxi is distributed in Fugu, Jiaxian, Wubao, Suide. The main coal types are long-flame coal and gas coal. , Fat coal , coking coal, characterized by low and medium ash, low phosphorus, high calorific value, 11 mineable coal seams, the maximum thickness of a single layer is 15.47 meters, covering an area of about 6631 square kilometers, adjacent to the Yellow River and Shanxi Province to the east see.
Figure 3, Northern Shaanxi Hengshan Coalfield
Northern Shaanxi Triassic coal is concentrated in Yan'an Pagoda District, Zichang, Fuxian (called Zichang Mining Area). The main characteristics of this coalfield are low-medium ash and low sulfur , high calorific value, 6 layers of coal seams can be mined, the thickness of a single coal seam is generally not more than 1 meter, and the area is about 4572 square kilometers.
Figure 4, Coal resource mining
The Jurassic Coalfield in northern Shaanxi is located in the north of Yulin City, Shaanxi Province, and borders the Dongsheng Jurassic Coalfield in Inner Mongolia to the north. The two are actually one body, and are collectively referred to as the Dongsheng-Shenfu Jurassic Coalfield in the Ordos Basin.
Figure 5. Coal mining
The Jurassic coalfield in northern Shaanxi is divided into Shenfu Xinmin Mining Area, Yushen Mining Area, Yuheng Mining Area and Jingding Prediction Area from the northeast end to the southwest end. The number of coal seams in the coalfield gradually decreases from east to west, with as many as 14 layers and as few as 9 layers, covering an area of 26,600 square kilometers.
Figure 6, Triassic paleoenvironment in northern Shaanxi
The main mineable coal seam structures are simple to relatively simple, with good coal seam stability and continuity. It is one of the eight largest coal fields in the world.
Figure 7, coal transportation
The coal seams existing in the Jurassic coalfields of northern Shaanxi are all non-stick coal and long-flame coal. Among them, the main mineable coal seams in Yushen Mining Area and Shenfu Xinmin Mining Area are extra-low ash and extra-low sulfur.
Figure 8, Northern Shaanxi Jurassic field coal seam
is a medium-high calorific value, low-melting ash coal, and has the characteristics of good thermal stability, high crushing strength, poor grindability, and high oil content. It is a high-quality chemical power coal. .
