Tonnage/Face-FEET Formulas

Approximate Weights per Cubic Foot

Michigan Granite Boulders = 170 lbs/cu ft
Michigan Limestone = 155 lbs/cubic ft
Canadian Limestone = 165 lbs/cubic ft
Michigan Grindstone = 136 lbs/cubic ft
1 Cubic Yard = 27 Cubic ft.
1 Ton = 2000 lbs.
1 Ton of Construction Aggregate = 3/4 cubic yd.
1 Cubic yd. of 4-12" Oversize Cobble Stone = Approx. 3,200 lbs.

Approximate Boulder Weights

Size Weight
12" 100 lbs
14" 125 lbs
18" 205 lbs
24" 253 lbs
30" 530lbs
36" 1100 lbs
48" 2800 lbs

Equations

AREA (Face Foot) = Length x Width (Height)
DEPTH (Feet) = Depth (Inches) / 12
*CUBIC FEET = Length x Width (Height) x Depth
*CUBIC YARDS = Cubic Feet / 27
CIRCLE AREA = 3.14 x Radius Squared
CIRCLE CIRCUMFERENCE = 3.14 x Diameter
TRIANGLE AREA = 1/2 of Base x Height
*TONNAGE = Cubic ft x lbs per Cubic ft / 2000
* Required

Michigan boulder coverage

Size Approximate Weights Approximate Face feet per ton
4-8" 20-60 lbs. 30-50
4-12" 20-100 lbs. 18-19
8-18" 100-200 lbs. 15-16
12-24" 125-200 lbs. 13-14
18-30" 205-530 lbs. 11-12
24-36" 250-1100 lbs. 9-10
30-42" 530-2000 lbs. 7-8
36-48" 1100-2800 lbs. 6-7
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