Abstract:
This paper pertains to management policy issues regarding production and transport of rock aggregate taken from borrow pits and used to construct and maintain roads. These activities are important financially to many agencies. The policy issues are (a) assignment of road projects to pits and scheduling of pit openings and closures to minimize the combined costs; (b) assessment of the opportunity costs of not opening a pit for aesthetic or ecological reasons; (c) fair appraisal of road construction costs in a timber sale agreement; and (d) a fair distribution of costs between parties that jointly use the same raw material source. Total costs comprises five components: unit costs for processing and transporting, a fixed intermittent cost, a fixed pit development costs, and a fixed pit restoration cost. All costs are discounted. Resolving these issues requires a multipit, multiroad, multiyear viewpoint, which is facilitated by an integer programming model. For each pit during each period, the model employs a 9,1 type of variable and two continuous variables that behave as integer variables. A continuous variable is defined for each pit-road pair for each time period for each type of material.
Supplemental Notes:
Proceedings of a work shop held June 16-19, 1975, in Boise, Idaho by the Transportation Research Board.
