Sustainable Closure for Our Clients, Our Communities, and Our Environment - One of the most critical aspects of sustainable design and management in mining is closure planning and implementation.
Ausenco is very experienced at developing closure plans to meet front-end and ongoing permitting requirements; and at the detailed design and implementation of specific closure designs. The closure planning and design typically involves a range of environmentally-based disciplines, but also includes a key socio-economic aspect, which is also within our experience and capabilities. An additional aspect, often overlooked, is the post-closure monitoring period.
Mine Closure Planning
Ausenco provides a full range of services required to prepare both conceptual and feasibility-level closure plans, typically required for permitting purposes and/or for costing purposes within PFS / FS studies. We also develop mine closure criteria, which are incorporated into designs of major facilities, such as linear infrastructure, Tailings Facilities, Heap Leach Pads, pits, etc. The primary environmental objective for the planning, design and implementation for closure is to arrive at acceptable levels of physical and chemical stability of the materials and facilities within the mine. In socio-economic terms, the local, regional and national communities related to the mining operation must transition to a sustainable situation during and after the operational life of that operation - Ausenco has specialists on-staff who can assist our clients in developing, implementing and monitoring these 'social-closure' plans.
Remediation of Abandoned Mine Sites
In most of the jurisdictions where Ausenco operates, there exist legacy mining facilities, largely the responsibility of governments, that require additional effort to reach acceptable standards of closure. While the technical expertise involved is similar to standard mine closure design, there are some important differences with respect to these 'abandoned' mine sites. In particular, it is common that the sites have already entered into a contaminating state, thus remediation of existing forms of pollution are often required. Ausenco is fully experienced at developing the studies and designs required to assist in remediating these sites and, ultimately, to return the site to a closed condition, where physical and chemical stability are within acceptable ranges of emissions standards.
Mine Closure Design and Implementation
Nearing the end of the operating life of a mine, Ausenco can offer a full range of technical support for the engineering required to finalize the detailed designs for closure construction, and also for decommissioning or re-purposing of some facilities, such as process plants and buildings. During the Mine Closure Implementation stage of the mine life, Ausenco's strong Project Delivery capabilities allow us to manage broad scopes for closure works, in a cost-effective and timely manner. As much as possible, we assist our clients in implementing progressive closure schemes, which eases the year-on-year impacts of capital outlays for closure.
Geochemistry and Water Quality
One of the key disciplines in closure planning and design for mines involves the geochemical processes related to Acid Rock Drainage and Metals Leaching, and their subsequent impacts on water quality. Ausenco staff are highly experienced at implementing an integral approach to evaluating and minimizing impacts on water quality. Our integral approach includes management of contact non-contact water sources within the mine, in order to limit water that might require treatment prior to final discharge. Water balance and mass balance modelling assist us in predicting the ultimate quantity and quality of water to be treated, in the event that this is deemed necessary to meet effluent limits.
As a final step in mine closure planning and design, Ausenco has extensive experience in process plant design, including Minewater Treatment plants, also known as 'Active Treatment'. Additionally, our specialists have experience in designing and developing so-called 'Passive Treatment' systems, typically as constructed wetlands. For a given project, we will evaluate a range of options for our clients, and have full capability to develop the designs for any preferred technical alternative.
For more information contact one of our Experts.