Henderson Operations Kicks off Reclamation Effort with Precision Helicopter Lift

November 29, 2024 - Deep in the rugged Colorado Rockies, Freeport’s Henderson operations recently launched a project to reclaim old mine workings with a high-elevation mission on the Continental Divide to dismantle and airlift massive steel structures from an old mine shaft. 

It took close cooperation between internal departments and external partners to safely remove the three 5,000-pound steel rings from the remote location. Despite the steep terrain and altitude challenges, the contractor crew needed just three hours to disassemble and use a helicopter to safely move the rings to the Henderson mine site.  

“This complex operation was only executed flawlessly because of the collaboration between the diverse teams,” said Geoff Niggeler, interim Mill Manager-Henderson, who led this effort in his previous role of Chief Environmental Engineer. “Most importantly, it was done safely.” 

Engineering an environmental triumph 

The path to success wasn’t straightforward. During the course of three summers, engineers conducted multiple site visits on foot and in utility task vehicles, analyzing the safest and most efficient removal method of the steel structures. Given the challenging terrain and the weight of the 5,000-pound steel rings, the team ultimately determined using a helicopter was the most practical way to transport them from 4-Shaft to the Henderson mine site for dismantling and recycling. 

“The shaft is only accessible by vehicle for about six weeks out of the year due to high mountain snow conditions, making project planning so important,” said Kasey Martin, Senior Environmental Engineer. “There was very little room for error in the schedule.” 

Historical beginnings 

The 4-Shaft was built in the late 1960s as a primary ventilation tunnel to exhaust air from the mine, helping to maintain proper airflow and ventilation for safe mining operations. In 1985, as the mine’s needs evolved, the 4-Shaft was found to be unnecessary, however, it was discovered that cold air coming in from 4-Shaft was hitting the warm air from the mine creating significant condensation on electrical equipment.  

A plate was installed to close the hole at the bottom, optimizing airflow. However, the steel structures on the surface of 4-Shaft remained, posing a reclamation challenge due to the site’s remote location near a public hiking trail and it being inaccessible by motorized vehicles most of the year. Additionally, the concrete around the steel structure had deteriorated, creating a safety hazard for passersby. 

Next steps in the remediation effort will include monitoring area vegetation growth and implementing any related action items, if necessary.

 

Photo: (top)The three rings of the 4-Shaft shown before their removal.