Study on Roof-Coal Caving Characteristics with Complicated Structure by Fully Mechanized Caving Mining

Table 4

Measured top coal block size.

Horizon	Measuring point 1	Measuring point 2	Measuring point 3	Measuring point 4	Measuring point 5	Measuring point 6
The lower top coal fragmental size (cm)	10	13	16	12	17	10
The middle and lower top coal fragmental size (cm)	42	47	49	46	50	40
The middle top coal fragmental size (cm)	18	20	21	18	23	16
The middle and upper top coal fragmental size (cm)	48	52	53	50	58	45
The upper top coal fragmental size (cm)	23	26	28	25	32	23