Freezing Method for Rock Cross-Cut Coal Uncovering: Aging Characteristic of Effective Freezing Distance on Injecting Liquid Nitrogen into Coal Seam

Table 1

The layout of thermometers.

Serial number of thermometer	Distance (cm)
No. 1 and No. 2	1
No. 3 and No. 4	10
No. 5 and No. 6	20
No. 7 and No. 8	30
No. 9 and No. 10	40