Table 1.

Sample details.

Samples	Formation	Coal seam number	Coal rank	Mad (%)	Ad (%)	Vdaf (%)
YL	Dalianhe formation	Middle coal seam	Low rank coal	5.71	1.19	47.60
SL	Shanxi formation	No.2	Low rank coal	9.66	12.73	35.76
LNC	Damiaozhuang formation	No.8	Medium rank coal	4.80	43.00	41.43
QN	Shanxi formation	No.6	Medium rank coal	1.15	17.75	34.70
ST	Shanxi formation	No.4	Medium rank coal	0.92	12.17	26.55
FGZ	Damiaozhuang formation	No.7	Medium rank coal	2.34	31.09	29.86
LJT	Damiaozhuang formation	No.8	Medium rank coal	1.22	24.91	20.86
XDW	Shanxi formation	No.1	High rank coal	1.33	20.70	10.74
XJ	Shanxi formation	No.3	High rank coal	1.16	9.50	10.06

M_ad, moisture, air-drying basis; A_ad, ash yield, air-drying basis; V_daf, volatile, dry ash-free.