Behaviors and Overlying Strata Failure Law for Underground Filling of a Gently Inclined Medium-Thick Phosphate Deposit

Figure 6

The phenomenon during the experiment. (a) Fissures that develop from the left upwards as the mining approach advances. (b) Fissures that develop form the right upwards as the mining approach advances. (c) Obvious stratification phenomenon during the collapse.

(a)

(b)

(c)