A city needs to increase its rubbish disposal facilities. There is a choice of two rubbish disposal areas, as follows.
Area A: A gravel pit with a capacity of 16 mil- lion cubic meters. Owing to the possibility of high groundwater, however, the Regional Water Pollution Control Board has restricted the lower 2 million cubic meters of fill to inert material only (earth, concrete, asphalt, paving, brick, etc.). The inert material, principally clean earth, must be purchased and hauled to this area for the bottom fil1.
Area B: Capacity is 14 million cubic meters. The entire capacity may be used for general rub- bish disposal. This area will require an average increase in a round-trip haul of 5 miles for 60% of the city, a decreased haul of 2 miles for 20% of the city. For the remaining 20% of the city, the haul is the same distance as for Area A.
Assume the following conditions:
. Cost of inert material placed in Area A will be $9.4/m^3.
. Average speed of trucks from last pickup to disposal site is 25 miles per hour.
. The rubbish truck and a two-man crew will cost $210 per hour.
. Truck capacity of 4.5 tons per load or 20 m^3.
“Sufficient cover material is available at all areas; however, inert material for the bottom fill in Area A must be hauled in.
Which of the sites do you recommend?