Rock formation

Bulk modulus

K/GPa

Shear modulus

G/GPa

Density

d/N·m⁻³

Angle of friction

f/˚

Binding power

C/MPa

Tensile strength

t/MPa

Sandstone

5.5

3.2

1900

29

2.2

2.5

Mudstone

2.5

1.5

1700

27

1.0

2.0

Medium-grained sandstone

6.0

4.2

2450

33.5

2.6

3.5

Sandy shale

5.4

3.2

2100

29

2.3

3

2 # coal

2.0

1.0

1400

27

1.0

1.5

3 # coal

2.0

1.0

1400

27

1.0

1.5

Sandy mudstone

4.8

2.6

1850

29

1.8

2.0