Is this enough information to estimate the R value of the refrigerator's insulation?

a a walk-in refrigerator 8x8x10 feet (640 cubic feet) is filled ninety percent with ice. There is no more electrical power, so food can only remain in cold storage as long as the ice lasts. Limiting opening the door to twice a day for meal prep, it takes 60 days for the ice to melt away through the drain. The ambient outdoor temperature averages 80 Fahrenheit over the 60 day period.

What is the R value of the walk-in refrigerator's insulation?

(Is this even enough information to find it?) I don't know the thickness of the insulation.

Does this seem reasonable, with standard thicknesses of commercially available insulation?

Should I say the ice lasts longer or shorter than 60 days? Should I provide them with a hailstorm during that period? (Not over their crops, of course.)

I'll provide more information in exchange for serious answers!