Why are piles of scrap lumber on construction sites often thrown away when these piles often contain good and usable pieces? O Scrap piles do not contain good and usable pieces or they would not be considered scrap. Construction personnel often Jack training in process management and how to minimize costs. O Scrap piles are always sold and never thrown away. O The cost of identifying, saving, and moving scrap materials usually exceeds the value of the scrap to the contractor