Macro-Micro Response Characteristics of Surrounding Rock and Overlying Strata towards the Transition from Open-Pit to Underground Mining

Table 1

Rock mechanical properties.

Lithology	Bulk density () (kN·m^-3)	Modulus of elasticity () (GPa)	Compressive strength () (MPa)	Poisson ratio ()	Tensile strength () (MPa)
Quaternary clay	18.00	3.28	5.12	0.46	0
Gray dolomite	25.80	9.93	29.10	0.31	0.71
Off-white coarse-grained dolomite	25.28	9.99	31.50	0.29	0.78
Dark gray cryptocrystalline dolomite	25.80	9.93	29.10	0.31	0.89
Layered muddy dolomite	26.20	9.14	24.78	0.28	0.92
Muddy dolomite	24.79	6.06	17.10	0.34	0.67
Phosphatic bed	19.50	8.10	22.87	0.39	0.88
Boundary phosphate rock	26.60	13.80	37.96	0.30	1.46
Off-white layered dolomite	26.24	14.60	48.13	0.28	1.66
Charcoal gray layered dolomite	25.00	15.80	39.35	0.33	1.40