Chemical Evolution Process and Quality Assessment of Seepage Groundwater in Tunnel Crossing Gas-Bearing Coal Seams

Table 6

Water quality classification results based on water quality indices.

Group	Sample	WQI	Water quality	Group	Sample	WQI	Water quality
I	1	47.18	Excellent	III	13	27.50	Excellent
	2	33.15	Excellent		14	27.70	Excellent
	3	29.65	Excellent		15	31.14	Excellent
	4	107.54	Poor		16	81.90	Good
	5	18.65	Excellent		17	33.48	Excellent
	6	38.24	Excellent		18	44.45	Excellent
	7	45.43	Excellent		19	27.45	Excellent
	8	44.48	Excellent		20	32.62	Excellent
II	9	38.65	Excellent	IV	21	18.98	Excellent
	10	18.45	Excellent		22	9.09	Excellent
	11	34.56	Excellent		23	31.08	Excellent
	12	39.05	Excellent		24	34.67	Excellent