A New Method for Controlling Rockbursts in the Mining Roadway of Ultrathick Coal Seams Based on the Dual Pressure Relief Method

Table 2

Changes in MS events within different energy ranges before and after dual pressure relief.

Energy range (J)	Number of MS events before pressure relief	Number of MS events after pressure relief	The number change of MS events before and after pressure relief	The percentage of the variation of MS events in the total number of MS events in corresponding energy ranges before pressure relief
[10^7, 10^8)	3	0	−3	−100
[10^6, 10^7)	14	12	−2	−14.3
[10^5, 10^6)	105	51	−54	−51.4
[10^4, 10^5)	202	102	−100	−49.5
[10^3, 10^4)	193	163	−30	−15.5
[0, 10^3)	105	135	30	28.6

Note: a negative number represents a reduction and a positive number represents an increase.