ACG Mine Closure 2024

Fort Collins aggregate mine planning for closure: optimising post-closure land use through mine operations

Jeremy Scott Collyard (co-written with Mark Arigoni) | Thursday, November 28th at 13:50

The Mine is a construction material aggregate mine outside Fort Collins, Colorado. Operating successfully for over 40 years, the mine is now nearing the end of its operational life. International Corporation assisted in the preparation of a mine planning update and vision that focused on meeting all regulatory obligations and optimizing the post-closure land use. Understanding that the closure obligations are defined by the state of Colorado Division of Reclamation, Mining and Safety (CDRMS) and the United States Army Corps of Engineers (USACOE), the project team worked collaboratively to evaluate, assess and develop a mine closure plan that delivers a project that not only meets regulatory requirements and is financially viable, but is also socially and contextually conscious, and allows for the successful operation of the mine in its remaining years.

The existing mine property is uniquely situated within a myriad of land uses that include agriculture, commercial, institutional, and residential. With the surrounding community context in mind, the potential post-closure land uses were evaluated for land value, compatibility, constructability, costs, implementation schedule, and future land use risks. Potential feasible post-closure land uses were defined and evaluated including residential, commercial, wetland mitigation banking, agricultural, recreation, and combinations of uses.

This approach required a multi-disciplinary team consisting of mining and civil engineers, landscape architects, ecology and wetland specialists, cost estimators, property valuation specialists, and permitting specialists. Conceptual closure alternatives were defined and evaluated resulting in a combination of post-closure land uses. Although the selected alternative resulted in a reduction in the aggregate to be mined, it was selected based upon the assessment of all criteria discussed above. This paper will present the process, alternatives, and the mine and closure plan as developed for the Timnath Mine.