Sustainability assessment of red sand as a substitute for virgin sand and crushed limestone

Abstract

This article assesses the sustainability benefits of replacing virgin sand and crushed limestone with Red Sand for road construction and top dressing. The sustainability of Red Sand was assessed using a triple bottom line analysis that includes economic, social, and environmental objectives. Each of these objectives consists of a number of headline performance indicators, with each being the aggregate of key performance indicators that measure whether Red Sand applications foster or impede sustainability. Red Sand is a newly developed product that is expected to be commercially available in 2014. It is produced by washing and carbonating the coarse fraction of the residue produced by the Bayer alumina refining process. Our assessment indicates that replacing virgin sand and crushed limestone with Red Sand will provide a range of financial and environmental benefits. For example, some environmental impacts associated with using virgin sand and crushed limestone, such as loss of biodiversity and land degradation, can be avoided by substituting Red Sand. Also, the use of Red Sand for road construction and top dressing is expected to conserve land and raw materials for future generations, thus enhancing intergenerational social equity. The energy consumption associated with producing Red Sand is projected to be lower than that required to quarry virgin sand and crushed limestone, thereby conserving energy and reducing the overall greenhouse impact of road construction and top-dressing applications that use virgin sand and crushed limestone. The greenhouse benefit of Red Sand is further enhanced by avoiding the loss of vegetation associated with sand and limestone quarrying. There are also intangible benefits expected from the substitution of Red Sand, including ecological, aesthetic, and recreational benefits associated with bushland conservation, a significant issue in areas surrounding metropolitan Perth.