Sumatra: Belinau underground mine now stable, Berenai-Nuri open pit redesigned
Tuesday, August 30 2016 - 04:17 AM WIB
ASX-listed Sumatra Copper & Gold plc provided Tuesday an update on the Belinau underground mine and Berenai-Nuri open pit mine at its Tembang gold and silver operation, located in Sumatra.
On July 26, the company announced that a geotechnical event had been experienced above Level 4 at the western end of Belinau. ?Over the past month the company has filled the void with competent rock from surface and the area is now stable with no anticipated threat to infrastructure,? Sumatra said in a statement.
The company said that the interim ore extraction method by ore drives for Levels 5 and 6 has begun and will provide a continuous ore supply to the mill until the decline reaches Level 8, where conventional stoping will resume.
?Over the next 3 months, the revised ore extraction method will result in lower ore production from underground versus the original plan as the decline advances,? it said.
The company said it also plans to acquire two smaller loaders to reduce the width of ore development to 2.5 meters from the previous 3.6 meters. This will reduce dilution and accelerate ore development. A number of other initiatives have been implemented to increase development productivity including: improved integrated scheduling of jumbo drill and ground support routines which has resulted in a 30 percent improvement in cycle times; introduction of airleg drills to bolt walls which has freed up jumbo drills to bore the face of the decline and development drives.
Sumatra said to compensate for the lower production from underground, the open pit mining schedule has been optimized with additional ore planned to be extracted from the Siamang open pit, where additional intermediary veins have been encountered, combined with a redesign and accelerated schedule for the Berenai-Nuri open pit.
The newly designed Berenai-Nuri open pit brings forward 83 percent of the contained ounces to be mined over the coming year by delaying the waste cutback to the north.
A comprehensive review of the company?s mine plan has been completed by the operations team led by new COO Rob Gregory. Guidance for full year 2016 is revised from 35,000 oz AuEq1 to 30,000 ? 33,000 oz AuEq, with an annualized production rate of 45,000 to 55,000 oz AuEq expected to be achieved during the first quarter of 2017.
Editing by Reiner Simanjuntak