Two-step CO2 Capture and Storage Technology using Seawater and Mineral Carbonation of Mine Water Pool of Sydney Coalfields

The goal of this project is to develop a point-source carbon capture and storage technology that: 1) uses a capture medium constituted from seawater; and 2) employs a technique that permanently sequesters the captured carbon as metal carbonates using the contaminated water of flooded former mines. This work will focus on the decommissioned mines of the Sydney Coalfield in Cape Breton and aims to be an inexpensive, portable, and easy-to-use procedure for capturing CO2 at the source.

Coal mining in Cape Breton's Sydney Coalfield lasted nearly three centuries, leaving behind ten abandoned and interconnected underground mines. These underground mines have been filled with roughly 190 million m³ of now contaminated water that is enriched in iron, sulphide, metals (e.g., calcium, magnesium and manganese), and metalloids, classifying it as acid mine drainage (AMD). Recent advances in the CO2 sequestration process have found that mineral carbonation, which involves a reaction between CO2 and divalent metallic elements such as calcium, magnesium, and iron, is the best and most energy-efficient option for permanently sequestering CO2. Hence, the mines of the Sydney Coalfield are an excellent candidate for the permanent sinking of CO2.

The transfer of captured CO2 to the sequestration location has faced prior scrutiny due to its resource-intensive nature, entailing substantial energy demands and expenses. This project aims to address those critiques and develop a cost-effective CO2 mineral capture process (at source) based on a proven method of using brine from seawater at source and a procedure to overcome challenges to direct mineral carbonation in mine water. Beyond our project's primary goal of carbon capture and storage, our anticipated two-step system will also help mitigate further AMD formation in the mines, thereby reducing the burden of mine water treatment.