Tag Archives: Arnaud Soirat

Rio Tinto’s Argyle diamond mine closes after 37 years of operations

Diamond mining, Mine operation news, Mining industry recognition, , , , ,

After 37 years of operations and having exhausted its economic reserves, the iconic Argyle mine in the remote east Kimberley region of Western Australia has celebrated its final day of mining.

The Argyle orebody, a single pipe known as AK1, was discovered in October 1979. Alluvial operations began in 1983, open-pit mining began in 1985 and the mine became a fully underground operation in 2013. Over this period of time, the mine has produced more than 865 Mct of rough diamonds becoming the world’s largest producer of coloured diamonds and virtually the sole source of a very small but consistent source of rare pink diamonds, according to Rio.

Arnaud Soirat, Rio Tinto’s Chief Executive of Copper & Diamonds, said: “Fifty years ago, there were very few people who believed there were diamonds in Australia – even fewer could have foreseen how the Argyle story would unfold. To arrive at this final chapter has required vision, courage and determination to overcome significant challenges to enter new territory in diamond exploration, mining and marketing.

“Today, Argyle’s influence stretches into many spheres and over many continents and I am very proud to acknowledge all those people who have contributed to the discovery and development of the mine and the production of some of the finest diamonds the world has ever seen.”

Argyle employees, Traditional Owners and local stakeholders attended an event at the mine, signalling the formal transition from an operational mine to the commencement of closure. The closure process is expected to take some five years to decommission and dismantle the mine and undertake rehabilitation, followed by a further period of monitoring. Argyle will employ a smaller workforce, post the final mining and diamond production activities, continuing to contribute to the local economy.

Andrew Wilson, General Manager of the Argyle mine, said “This is an historic day for the Argyle mine and the east Kimberley region and a great source of pride for this unique Australian success story. A new chapter will now begin as we start the process of respectfully closing the Argyle mine and rehabilitating the land, to be handed back to its traditional custodians.”

Oyu Tolgoi loses some of its underground reserves following updated feasibility study

Base metals, Mineral project development, Precious metals, , , , , , , , , , ,

An updated feasibility study on the development of the underground mine at Oyu Tolgoi, in Mongolia, has confirmed that the huge copper-gold project will be delivering sustainable production later than initially planned and this output will come with a higher capital expenditure bill.

Majority owned by Rio Tinto through its 66% stake in Turquoise Hill Resources, Oyu Tolgoi is currently being mined as an open-pit operation (producing 146,346 t of copper and 241,840 oz of gold in 2019), yet previous studies have indicated a combined open-pit and underground operation could up the tally to around 500,000 t/y of copper.

Back in July 2019, Rio Tinto included an update on the underground project saying first output was expected to be achieved between May 2022 and June 2023, a delay of 16 to 30 months compared with the original feasibility study guidance in 2016, while preliminary estimates for development capital spend was $6.5-$7.2 billion, $1.2-$1.9 billion up on the $5.3 billion previously disclosed.

The updated feasibility study issued this week from Oyu Tolgoi LLC (owned 66% by Turquoise Hill and 34% by the Mongolian government), which is in the process of being submitting to the Government of Mongolia in accordance with Mongolian regulations and standards that require mining companies to submit updated feasibility studies every five years, includes a delay of 21 to 29 months for first sustainable production compared to the original feasibility study guidance in 2016 and an increase of $1.3-$1.8 billion from the original $5.3 billion development capital.

This process has also seen 1.22 Mt of copper, 850,000 oz of gold and 7.01 Moz of silver removed from the Hugo Dummett North reserve base compared with the December 31, 2019 calculation, with some 80,000 t of copper, 70,000 oz of gold and 550,000 oz of silver added to the Hugo Dummett North Extension reserve base.

It also includes a new mine design for Panel 0 of the Hugo Dummett North underground mine at Oyu Tolgoi, as well as confirming that the caving method of mining remains valid.

Detailed study, design, engineering and optimisation work is ongoing to support the definitive estimate of Panel 0 for the development of this orebody, which remains due in the second half of 2020, Rio said.

These estimates are subject to any additional scheduling delays or increases in capital costs arising from the impacts of the ongoing COVID-19 pandemic, it added.

Back in July 2019, Rio said enhanced geotechnical and geological information obtained from drilling and mapping at depth suggested there may be some stability risks associated with the original mine design. This updated design was the result of a review of this information.

The updated design retains two in-situ rock pillars on either side of Panel 0 for geotechnical stability, whereas the original mine design had these pillars within the mining area. “The updated design is supported by extensive geotechnical modelling and industry leading technical assurance,” Rio said.

As a consequence of leaving the pillars in place, the material contained in the pillars has been reclassified from reserves to resources, Rio said, adding that part of the material contained in these pillars could be recoverable at a later stage following additional studies currently underway. This saw 2.43 Mt of copper, 570,000 oz of gold and 4.81 Moz of silver added to the July 3, 2020, Hugo Dummett North resource base.

Ore handling infrastructure will be relocated to the pillars, located immediately north and south of the current Panel 0 boundaries, Rio explained, with Panels 1 and 2 now be initiated as independent panels or mine blocks.

Optimisation of mine designs for Panels 1 and 2 is ongoing and it is anticipated that this next phase of study may result in further movements in classifications of reserves and resources, according to Rio.

Arnaud Soirat, Chief Executive of Copper & Diamonds, said: “This amended mine design is another positive step in the development of the underground mine which will unlock the most valuable part of Oyu Tolgoi. We remain focused on delivering the underground project safely and within the guidance ranges we have announced on both cost and schedule.”

Rio, Turquoise Hill put forward coal power plant option for Oyu Tolgoi

Base metals, Environmental, Mine operation news, Power supply for mines, , , , , , ,

Rio Tinto says it is continuing to progress options to secure domestically sourced power for its majority-owned Oyu Tolgoi copper mine in Mongolia.

The mining major’s domestic search for energy is part of an obligation to source power by June 30, 2023 under the 2009 Investment Agreement between Turquoise Hill Resources (which owns 66% of Oyu Tolgoi), the Government of Mongolia and Rio Tinto, and the subsequent Power Sector Framework Agreement signed in 2018.

In compliance with these agreements, Oyu Tolgoi LLC has submitted to the Government of Mongolia a feasibility study for the Tavan Tolgoi Power Plant (TTPP) project, which involves building a 300 MW coal power plant. This plant, to be located in Tsogttsetsii soum of Umnugovi province, comes with a total project cost estimate of up to $924 million, pending consideration of certain amounts yet to be finalised, Turquoise Hill said. Rio says this amount is already included in the group capital expenditure guidance of $7 billion in 2020 and $6.5 billion each in 2021 and 2022.

In parallel with the TTPP project, and in consultation with the Government of Mongolia, Rio Tinto is also progressing alternative options to source domestic power, including a renewable power component, Rio said.

Oyu Tolgoi is currently sourcing power from China’s Inner Mongolian Western Grid via overhead power lines, via a back-to-back power purchase agreement with National Power Transmission Grid JSC, the power importing entity, and the Inner Mongolian Power Company, according to Turquoise Hill.

Rio Tinto Copper & Diamonds Chief Executive, Arnaud Soirat, said: “Rio Tinto, Turquoise Hill and the Government of Mongolia are all committed to securing a reliable and long-term domestic power source for the Oyu Tolgoi mine and are working together to achieve this.”

Rio revises Oyu Tolgoi cost and production estimates on rock stability issues

Base metals, Bulk handling, Mine shafts and equipment, Mineral project development, Precious metals, , , , , , , ,

Rio Tinto has provided an update on its majority-owned Oyu Tolgoi copper-gold underground project, in Mongolia, admitting that stability risks identified with the previously approved mine design has led to an estimated cost increase and delay to first production.

First output is now expected to be achieved between May 2022 and June 2023, a delay of 16 to 30 months compared with the original feasibility study guidance in 2016, while preliminary estimates for development capital spend is now $6.5-$7.2 billion, $1.2-$1.9 billion up on the $5.3 billion previously disclosed.

These estimates are preliminary in nature – the equivalent of a conceptual or order of magnitude study – but Rio said a definitive estimate should be forthcoming in the second half of 2020.

Oyu Tolgoi Underground is Rio’s major copper growth project. When the underground mine is fully ramped up, the existing open pit and underground, combined, are expected to produce more than 500,000 t/y of copper.

Alongside this announcement, Rio Tinto also published its June quarter production results, which showed Rio’s share of production of the Oyu Tolgoi open-pit mine was 13,100 t of copper over the period.

Since February, key below ground infrastructure such as the control room facility and the jaw crusher system have been completed and construction of shafts 3 and 4 is progressing well, according to Rio. The commissioning of shaft 2 remains on track for October 2019.

As Rio previously advised, enhanced geotechnical information and data modelling suggests there may be some stability risks identified with the approved mine design. As a result, several other mine design options are under consideration to complete the project.

Rio said: “Studies to date indicate that these options may result in some of the critical underground infrastructure, such as the mid-access drive and the ore handling system, being relocated or removed. Options relating to the sequence of crossing the panel boundaries during mining operations are also being analysed.”

These options are being evaluated to determine the final design of the first panel of mining, “Panel 0”, with the work anticipated to continue until early 2020, Rio said. This is where the definitive estimate date of the second half of 2020 comes from. This estimate will include the final estimate of cost and schedule for the remaining underground project and the preferred mine design approach.

Rio said: “All options under consideration present a pathway to sustainable first production, and have different cost and schedule implications. To date, these have been defined to a level of accuracy associated with a conceptual study or order of magnitude study, and, therefore, significantly more work is required to complete the final assessment.”

Preliminary information now suggests, depending on which mine design options are adopted, first sustainable production could be achieved between May 2022-June 2023. This range includes contingency of up to eight months reflecting the “unexpected and challenging geotechnical issues, complexities in the construction of shaft 2 and the detailed work still required to reach a more precise estimate”, Rio said.

The company added: “The company will continue to focus on minimising the impact to project schedule and cost, as it works through the detailed analysis and testing of each mine design option. Although further work is necessary to reach definitive conclusions, Rio Tinto is reviewing the carrying value of its investment in the project and will announce if any changes are required in the half year results on August 1, 2019.”

Stephen McIntosh, Group Executive, Growth & Innovation, said: “We have made significant progress on a number of key elements in the construction of the underground project during 2019. However, the ground conditions are more challenging than expected and we are having to review our mine plan and consider a number of options. Delays are not unusual for such a large and complex project, but we are very focused as a team on finding the right pathway to deliver this high value project.”

Arnaud Soirat, Chief Executive, Copper & Diamonds, said: “Oyu Tolgoi is a world-class orebody and a world-class business that is already producing copper, employing around 16,000 people and benefitting Mongolia through taxes, royalties and significant procurement. We are working with Turquoise Hill Resources and the Government of Mongolia to complete the underground, which will unlock the most valuable part of the mine for the benefit of all stakeholders.”

Oyu Tolgoi is owned 66% by Turquoise Hill Resources (THR) and 34% by the Mongolian government, with Rio Tinto holding a majority stake in THR.