Soil and Rock - Bulk Factors

Soil and rock expansion - or swell - after mining. One cubic meter from the borrow expands when dropped on the lorry or landfill, translating borrow volume to dump volume using bulking factors.

Material	Density at Borrow (kg/m³)	Bulking (Swell) Factor (%)
Basalt	2.4 - 3.1	75 - 80
Clay	1.8 - 2.6	20 - 40
Dolomite	2.8	50 - 60
Earth		20 - 30
Gneiss	2.69	75 - 80
Granite	2.6 - 2.8	75 - 80
Gravel, dry	1.80	20 - 30
Gravel, wet	2.00	20 - 30
Gravel, wet w/clay		50 - 60
Limestone	2.7 - 2.8	75 - 80
Loam		15 - 25
Quartz	2.65	75 - 80
Rock		40 - 80
Sand, dry	1.60	20 - 30
Sand, wet	1.95	20 - 30
Sandstone	2.1 - 2.4	75 - 80
Slate	2.6 - 3.3	85 - 90
Soil	1.2 - 1.6	20 - 30

Calculator

Inputs

Borrow Volume (m³)

Bulking (Swell) Factor (%)

Results

Dump Volume-- m³