| Popis: |
One of the main requirements of rehabilitating an old mine site is to safely secure and cap mine openings to ensure public safety. For remote sites, current options (such as concrete caps) are less effective from an economic perspective, and are generally associated with important environmental impacts mainly related to construction of access roads and development of working areas. This paper presents a relatively novel approach for shaft capping which was implemented in Manitoba at a large number of orphaned and abandoned mine sites, using polyurethane foam as sealant for mine openings and workings, such as shafts, adits, exploration trenches, and steep excavations that pose a threat to public safety. The paper presents criteria used in establishing a safe sealant medium, and presents a summary of the laboratory testing completed to confirm material performance, its physical, structural, and chemical characteristics. The paper also provides a comparison between the use of this technology and the more traditional concrete capping option. For remote sites, the new technology is significantly more efficient. Several case studies from Manitoba are presented where the use of polyurethane foam proved to have minimal negative impact on the surrounding environment, the solution being less invasive and resulting in minimal ecosystem and ground disturbance. Recommendations for future uses and limitations of this technology are also provided. |
