In its Q3 2020 and nine months to September 30 results, Freeport McMoRan reports that ramp-up of the Grasberg underground copper-gold mine in Indonesia is advancing on schedule. The mine is operated by PT Freeport Indonesia’s (PT-FI) , which is held 51.2% by PT Indonesia Asahan Aluminium (Inalum) and 48.8% by Freeport McMoRan.
During third-quarter 2020, a total of 55 new drawbells were added at the Grasberg Block Cave and Deep Mill Level Zone (DMLZ) underground mines, bringing cumulative open drawbells to over 300. Combined average production from the Grasberg Block Cave and DMLZ mines approximated 60,000 t of ore per day during third-quarter 2020, 9% above the second-quarter 2020 average but approximately 15% below the July 2020 estimate, primarily reflecting unplanned downtime and a brief labor-related work stoppage.
However, metal volume targets were achieved during third-quarter 2020 as a result of higher ore grades. For the month of September 2020, combined average production from the Grasberg Block Cave and DMLZ mines totaled approximately 75,000 t of ore per day and the ramp-up schedule remains on track. PT-FI expects its 2021 production to approximate 1.4 billion pounds of copper and 1.4 Moz of gold, which is nearly double projected 2020 levels. The successful completion of this ramp up is expected to enable PT-FI to generate average annual production for the next several years of 1.55 billion pounds of copper and 1.6 Moz of gold at an average unit net cash cost of approximately $0.20 per pound of copper assuming an average price of $1,400 per ounce of gold and achievement of projected sales volumes and cost estimates.
Tunnel General Superintendent, I Made Pasek from contractor Redpath reported recently on its contribution to the underground progress: “The Grasberg Block Cave (GBC) Project, since drawbell production start-up in Q4 2018, continues to maintain momentum, earning world class project status. During the month of March 2020, Redpath’s GBC production team recorded one of the best months since startup, by achieving record breaking tonnage of 24,000 metric tonnes per day. Redpath, together with the client, PT Freeport Indonesia, and charging and blasting contractor, also achieved record monthly drawbell blasting accomplishments. Fifteen drawbells were completed, tallying a major milestone of 100 drawbells for the GBC project overall, to date.”
He added: “In order for Redpath’s GBC production team to maintain performance, key aspects were implemented. Thorough daily planning and scheduling of equipment and training resulted in a robust and flexible crew. An equally successful production drilling crew, operating Solo drills, and a slot raise crew, operating Redbore 50X raise drills, contributed to the record achievement. Such impressive production results would not be possible without the commitment towards a strong safety culture that is deeply rooted in the GBC operations.”
