Fort Knox’s Walter Creek Heap Leach (WCHL) facility was constructed and first used in 2009, and by 2017 more than 243 million tons of ore had been stacked on the pads, with 1 million ounces of gold recovered.
This successful track record reached a roadblock this year as flat areas for leaching were less available. As ore was stacked over the years, the pads grew further back into the valley where it is situated, and the configuration made it difficult to access front facing sections of the pads for leaching.
Tasked with finding a solution, a multidisciplinary team from Ore Processing, Mine Operations, Technical Services, Continuous Improvement and Metallurgy worked together to find an approach to safely extract gold from ore on the front face of the pad at the lowest possible cost.
The team worked collaboratively over several months exploring options and decided re-grading the front face of the pad was the best solution. The Technical Services team then developed a plan to protect the pad liner and piping while performing the re-grade.
In two months, 7 million square feet of front face pad was re-surfaced — ahead of schedule and with no damage to the pad liner or piping.
Since the re-grade in July, the WCHL facility has recorded 25% of its production from front facing ounces and is saving approximately $100,000/month on solution pumping by passing the booster station to the front slope.
“We are very proud of the team at Fort Knox who delivered this project ahead of schedule, under budget, but most importantly with safety as their top priority,” said Brandon Holm, Mine Superintendent, Fort Knox. “This was a true example of teamwork between multiple departments in an effort to enhance our operations and increase cash flow.”