TORONTO (miningweekly.com) – The largest gold producer by market capitalisation Goldcorp on Tuesday announced that higher-than-expected folding and faulting at the Éléonore mine, in the James Bay region of Quebec, has resulted in it revising downwards the young mine’s 2015 production guidance.

Ahead of an upcoming analyst and investor tour at the Éléonore mine, Goldcorp explained that with the first mining stope from Horizon 4 now under way, in-situ ore grades had been as expected; however, higher than expected folding was being encountered, which resulted in higher dilution and, therefore, lower-than-planned mined grades and gold output.

“The Éléonore team is working to adjust stope design to [reduce] these impacts,” the company advised in a statement.

The Roberto deposit was hosted in sedimentary rock and mined material from all four horizons had identified a range of folding and faulting, consistent with the host rock package.

As a result of these conditions, Goldcorp had revised 2015 gold production guidance at Éléonore to between 250 000 oz and 270 000 oz, down from earlier estimates of between 290 000 oz and 330 000 oz.

However, the company reiterated that its overall gold output remained on track, with guidance unchanged and expected at the higher end of a range between 3.3-million ounces and 3.6-million ounces.

With first gold production achieved on October 1, 2014, Éléonore on April 1 declared commercial operations. The Éléonore mill ramp-up continued to progress successfully, with daily throughput averaging 5 418 t in August and achieving nameplate capacity of 7 000 t on August 11. Ramp-up of the mine and mill to full throughput of 7 000 t/d remained on track for the first half of 2018, the company affirmed.

Further, work on the Éléonore crown pillar prefeasibility study continued to advance in the third quarter, and was expected to be complete by year-end. Activities included progressing the trade-off study between openpit and underground mining, determining the dike location, permitting and stakeholder engagement.