While Leeville’s newly completed and commissioned Turf No. 3 Vent Shaft marks a successful end to many years of hard work by countless employees and contractors on the surface, much of the project’s success also can be credited to the work that took place underground. As noted by Leeville Mine Manager, Mark Ward, the planning, engineering and labor that was required underground just to reverse the flow of fresh air through the mine took more than a year.
Mark explained that at the same time the Turf vent shaft and related facilities were being built on the surface, several underground ventilation raises (vertical air conduits) were being excavated and connected between all levels on the Turf side of Leeville. The additional raises were needed to increase air flow through that part of the mine once the new shaft was completed and the existing air flow was reversed. To complicate matters, active mining and development continued on the same levels where the raises and bulkheads (barriers that direct and control air flow) were being constructed, adding to traffic congestion in an already confined area. Mark was proud to point out that the careful management and movement of large, space-consuming materials needed for the underground construction – massive vent doors, supplies and heavy equipment – proceeded without any safety issues and without significantly impacting production schedules.
Materials management challenges aside, more formidable obstacles awaited the teams in the very ground they were trying to modify. Mark reported that various geotechnical issues encountered during underground construction forced the teams to rethink where most of the new raises would be located. “Anytime they hit bad ground, the teams quickly analyzed the problems, reviewed alternative areas, reconfigured airflow models, and implemented solutions to keep the project on track,” he said, adding that at the end, despite all the hurdles, the work was actually completed ahead of schedule.
It was understood that upon the reversal of airflow, work at Leeville would need to be temporarily suspended long enough for dust to subside and for ground conditions to be inspected (due to the sudden change from warm, moist air to cold, dry air in some parts of the mine). Remarkably, that transition process went smoothly enough for Leeville to return to normal operation in under two days.
Hats off to all the Newmont teams, individuals and contractors involved in the underground phase of the Turf No. 3 Vent Shaft project! As Mark commented, it was “one of the most impressive examples of collaboration, teamwork and perseverance by everyone involved.”