Methane Extraction from Abandoned Mines by Surface Vertical Wells: A Case Study in China

Table 2

Representative methane extraction effect of surface wells in the abandoned mine.

Methane extraction time (d)	Well number (#)	Average concentration; Minimum~maximum (%)	Average methane flow rate; Minimum~maximum (m^3/h)	Cumulative methane flow (m^3)
1100	4	81; 63~89	76; 60~88	2.0 × 10^6
663	5	85; 79~95	80; 63~88	8.3 × 10^5
1016	6	83; 77~95	159; 139~210	4.4 × 10^6