Assessing Impacts of Megaquarry Development in the Cement Industry through Spatial and Transportation Network Analysis
The most recent measures of cement production estimate 97.4 million metric tons are produced annually in the U.S., and global production is estimated at 2.1 billion metric tons. In an increasingly globalized economy, cement is shipped long distances to meet demand. Other quarry products used in construction, such as aggregates, have moved toward large-scale centralized production sites, or “megaquarries”. Despite the cost of transport, these heavy low-value materials are moved long distances, even crossing
oceans, to reach markets. Cement production facilities, usually a co-located limestone quarry and cement plant, face many of the same barriers to siting and incentives for increasingly centralized production as aggregate quarries. This research examines the impact on sustainability, focusing on transport related energy consumption, of a trend towards megaquarry production in the cement industry. A number of factors affect potential cement megaquarry sites; the quality and extent of mineral resources, barriers to permitting, and accessibility to markets. These factors are modeled using tools from geographic information science including overlay analysis to determine feasibility of siting, and transportation network analysis to analyze a site’s accessibility to markets and the cost and energy consumption associated with distribution. Results compare the cost and energy associated with supplying the region from an optimally-sited megaquarry facility with the costs and energy resulting from an optimized distribution scenario for the existing cement production facilities in the region. Modeling results show megaquarry development in the region is economically and geologically feasible, but not favorable from the perspective of transport-related energy and its associated environmental impacts. Additionally, the study shows that evaluating distribution networks for economic costs rather than energy efficiency results in different optimal scenarios. Since companies generally will choose to reduce economic costs, this suggests cement will be transported sub-optimally from an energy efficiency perspective.