Page:Shop management.djvu/170

163 Table 3 (page 164) gives the times for throwing earth to different distances and different heights. It will be seen that for each special material the time for filling shovel remains the same regardless of the distance to which it is thrown. Each kind of material requires a different time for filling the shovel. The time throwing one shovelful, on the other hand, varies with the length of throw, but for any given distance it is the same for all of the earths. If the earth is of such a nature that it sticks to the shovel, this relation does not hold. For the elements of shoveling we have therefore:

s=time filling shovel and straightening up ready to throw. t=time throwing one shovelful. w=time walking one foot with loaded shovel. w$1$=time returning one foot with empty shovel. L=load of a shovel in cubic feet. P=percentage of a day required for rest and necessary delays. T=time for shoveling one cubic yard.

Our formula, then, for handling any earth after it is loosened, is:

Where the material is simply thrown without walking, the formula becomes:

If weights are used instead of volumes: