A Preliminary Assessment of a Limestone Quarry’s Direct and Indirect Carbon Footprint

Abstract

As a sub-sector of the mining industry, quarrying is also responsible for greenhouse gas emissions. Limestone is one of the most frequently extracted minerals used for construction, building materials and industrial applications. A common way limestone is consumed is for the production of lime, cement, steel, etc. Based on literature review, the amount of carbon emissions per ton of lime and cement was compared to the amount of expected carbon emissions per ton of limestone for a quarrying operation. The carbon emissions for the studied quarry were calculated using the CO2-equivalent metric in kilograms per ton of limestone, similar to other quarrying operations. A computer script model based on practical theoretic models and rules of thumb was created, aimed to simulate different states of the quarrying operation. A review of literature and modeled results show that the studied quarrying operation is responsible for significantly less carbon emissions, compared to the emissions related to the production of lime and cement. Additionally, based on a non-linear optimization model, different strategies related to the reduction of the carbon footprint for quarrying operations have been established for the design of blast patterns. These practices can serve as a preliminary way of assessing the direct and indirect carbon footprint related to limestone quarrying for future mining operations. Moreover, the effect of the chosen optimization function has also been studied. It resulted in the conclusion that the vector of the optimal solution based on the direct carbon footprint of the quarry can be biased, compared to the one obtained via the indirect and direct emissions approach.