How large is a 60,000 ton pyramid?

From In this thread, we give bad advice:

It’s Memorial Day, and you deserve a memorial! Don’t you want future generations to remember you? Of course you do! So order 60,000 tons of stone blocks and get to work building that pyramid you’ve always dreamed of. Build in right there in your backyard so your neighbors can see how important you are! Then, when you die, have yourself mummified and sealed in that pyramid! For thousands of years to come (or until the local zoning board orders it demolished) everyone will remember you as that idiot who built a pyramid to himself, went bankrupt and died of exhaustion!

Let’s assume the stone blocks are limestone. One source I read says limestone has a density of 2.71 g/cm³. The person who wrote the post was American, so he was thinking “U.S. ton”, which is 2,000 pounds.

• 60,000 tons of stone is 120,000,000 pounds, which is 5.4431084e+10 grams
• Divide that by 2.71 and you get 20,085,270,849 cm³ = 20,085 m³ = 709,305 cu. ft.
• Let’s assume a 10×10×8 foot room inside for the coffins of two people. That increases the overall volume to 710,105 ft³. There also needs to be a passageway (3 feet wide, 7 feet high) leading to this room, but its distance is currently undetermined because we don’t yet know how far into the pyramid the mortuary will be.
• The formula for the volume of a pyramid is V=(s²h)/3
• The slope of the Great Pyramid of Giza is 51°52’ (51.867°). We need this information to help calculate the height, since at this point it’s unknown.
• Also unknown is the base area
• Fortunately for a person who has essentially lost his algebra skills, I found The Pyramids Calculator. A simple web form has inputs for the following; one can enter an input into any two boxes and have the form compute the rest:
  • Base edge
  • Perpendicular height
  • Slant edge length
  • Slant height
  • Volume
  • “fb” angle (degrees)

The result:

Now that we know the pyramid is 150’ at the base and 95 feet high, let’s place the mortuary a quarter of the way up, or at 23’ altitude.

• At that height the base edge is 150-(23×sin(51.867)×2) = 113.8 feet, and the ceiling’s base edge is 150-(31×sin(51.867)×2) = 101.2 feet (meaning the room is well contained within the pyramid.)
• Removing 10 feet from the 113.8 feet of the base leaves 103.8 feet, and (assuming the room is in the centre of the pyramid) that leaves a corridor length of 51.9 feet.
• Therefore the corridor to the mortuary occupies 51.9×3×7 = 1,090 ft³ (more than the mortuary itself)
• Discounting the volume otherwise occupied by the slope, the volume of the pyramid is now 711,195 ft³

Plugging the new volume into The Pyramid Calculator, we get:

Basically there’s no change in the height when increasing the volume by a small amount for the access corridor.