So...divide by 12 and its still a lot of sand. Whoops.
So if that is 13 yards and that equals 13 tons--approx.
And if you used a Lesco spreader and applied 50 pounds at a time.
That would be 538 spreads, returns to pile, refills and returns to left-off point.
So...if an acre is 208 feet on a side, and we agree that the longest trip to refill would be the diagonal to the far corner (295 ft), and if we assume the average distance traveled to refill would be half of that (147 ft).
And if we suppose that the average speed of the operator is 3 mph which is 264 feet per minute. Then it would take .56 of a minute or about 34 seconds. Add the coming and going trip and that is 68 seconds.
Times 528 equals 35,904 seconds.
Then we have 10 hours, just in back and forth travel time. Approx.
That is without accounting for the actual spread time, and the time to shovel the sand into the spreader.