Question: As coal deposits are depleted, it becomes necessary to strip-mine larger areas for each ton of coal. Figure 5.43 shows the number of acres of land per million tons of coal that will be defaced during strip-mining as a function of the number of million tons removed, starting from the present day.
(a) Estimate the total number of acres defaced in extracting the next 4 million tons of coal (measured from the present day). Draw four rectangles under the curve, and compute their area.
(b) Re-estimate the number of acres defaced using rectangles above the curve.
(c) Use your answers to parts (a) and (b) to get a better estimate of the actual number of acres defaced.
