Field Study on the Law of Surface Subsidence in the High-Intensity Fully Mechanized Caving Mining Working Face with Shallow Thick Bedrock and Thin Epipedon in Hilly Areas

Table 3

Calculation of subsidence speed of the maximum subsidence point.

Serial number	Observation date		W (mm)	Days interval	Subsidence interval difference (mm)	V (mm/day)	Distance to working face (m)
1	1st observation	2nd observation	11	27	299	11.1	−198.0
2	3rd observation		310				−129.9
		4th observation		35	293	8.4
3	5th observation		603				−67.7
		6th observation		23	367	16.0
4	7th observation		970				35.8
		8th observation		20	2363	118.2
5	9th observation		3333				153.3
		10th observation		37	40	1.1
6	11th observation		3373				333.3
		12th observation		48	45	0.9
7	13th observation		3418				—
		14th observation		46	1	0.02