liquefied natural gas Archives - International Mining

Ora Banda Mining and Wesfarmers’ liquified natural gas business, EVOL LNG, have signed a new long-term agreement to bring LNG to the Davyhurst gold mine in Western Australia’s Goldfields region.

The gold mine is aiming to restart production in January 2021 after being placed into care and maintenance in 2018.

Ora Banda’s definitive feasibility study (DFS) for the Davyhurst Restart project outlined a production target of 418,000 oz of gold over an initial five-year mine life based on an ore reserve of 460,000 oz (6.1 Mt at 2.4 g/t Au) from six deposits within 50 km of the existing 1.2 Mt/y plant. The plant is being refurbished by GR Engineering Services.

EVOL LNG’s Manager, Nick Rea, said the business had proven its winning LNG solution to the mining industry over the past 12 years with its customer base continuing to grow.

“We are excited to support the Davyhurst mine back into production,” he said. “Ora Banda is now our ninth mining customer and we are keen to provide them with the benefits and value that are afforded to EVOL LNG’s customers.”

EVOL LNG will build, own, operate and maintain the on-site LNG storage and vaporisation facility at the mine. The facility will use EVOL LNG’s modular design, which, the company says, allows for fast installation and expandability if the mine’s energy requirements increase in the future.

Ora Banda Mining’s Managing Director & CEO, David Quinlivan, said: “Ora Banda’s agreement with EVOL LNG has enabled the company to secure a stable long-term energy solution for Davyhurst on terms consistent with those outlined in the DFS. The use of LNG as the primary fuel source for the Davyhurst power station also provides significant
environmental benefits.

“The company estimates its power generation greenhouse gas emissions will be reduced by approximately 25,000 t during the initial five years of operation when compared to conventional diesel power generation.”

The mine will use EVOL LNG to fuel a 7.5 MW gas-fired power station, with supply planned to commence from December 2020.

The LNG will be supplied from EVOL LNG’s Kwinana production facility in Western Australia, which was expanded earlier this year. Planning is underway for the next expansion to meet the growing market demand.

Caterpillar has been showing one of Mexico’s biggest gold mining operations that its Dynamic Gas Blending™ (DGB) technology can provide savings on fuel costs and emissions while maintaining the same performance, payload and productivity of its diesel haul trucks.

The mining OEM and its Mexico-based dealer, Matco Cat, have been working with Fresnillo’s Penmont division to convert its entire fleet of large mining trucks at the La Herradura open-pit mine, in Sonora.

Caterpillar’s dual-fuel DGB technology, which has accumulated 10 million hours in the oil and gas industry since 2013, works by blending lower cost liquefied natural gas (LNG) with diesel fuel, according to Cat.

The resultant improvements in fuel, emissions and maintenance can add up to millions of dollars each year in cost savings, Cat said.

La Herradura, since 2016, has acted as a great case study for the technology given it has more than 250 Cat trucks and the operation hauls at least 25 Mt of volume per quarter (based on Fresnillo’s most recent Q4 production results).

In addition, the company has been looking for ways to “produce (gold) in a sustainable manner”, Fresnillo’s Abel Villa said in a recent Cat customer story.

According to Steve Igoe, Commercial Manager for Caterpillar’s Gas Engine Business, the benefits of DGB technology include, primarily, a lower cost per tonne, realised through a lower fuel cost. “DGB truck operation with LNG has proven very beneficial to La Herradura, and this is why they have decided to convert their entire fleet,” he said.

“Typically, LNG is 30% lower than the price of diesel. And, on a typical fleet at a mine, that adds up to millions of dollars a year,” he said. “And the trucks maintain the ability to operate 100% on diesel.”

Cat estimates a fleet of 100 trucks spends approximately $60-70 million/y on diesel fuel. With 65% displacement to LNG using DGB, that fleet could save $13 million/y on fuel alone.

DGB can also bring about a 30% cut in emissions compared with diesel-only operation – another important saving for mining companies looking at sustainability.

Trials during 2016 and 2017 of the technology at a gold mine in Turkey and a phosphate mine in the US have proven these claims.

For instance, the Turkey gold mine has retrofitted DGB technology on Cat 150-ton (136-t) 785C haul trucks and, since installation, has reached an average 70% average fuel displacement in addition to an operating cost reduction of $30/h.

Fresnillo’s Villa said La Herradura had gone further than this in terms of displacement.

“Initially when we started the project, the substitution rate was 70:30. We evaluated the results and changed the substitution to 85:15,” he said. This is close to the peak substitution rate Cat typically recommends.

Villa continued: “We have an average reduction of 70% in diesel consumption. We also considerably reduced the amount of emissions. When we compare both diesel and gas, the operation is the same.”

Cat said it observed a less than 1% difference in speed, payload and gear shifting, plus a 30% reduction in fuel cost, during one customer’s 5,000-h DGB trial.

La Herradura has also seen no unexpected maintenance issues during the trials, according to Fresnillo’s Enrique Leal. This is in keeping with Cat’s focus on reliability and productivity, with the company saying it has tallied zero hours of unplanned downtime.

So far, La Herradura has retrofitted 31 of its 785C haul trucks and a significant number of 240-ton (218-t) 793D trucks with the DGB technology.

Fresnillo’s Villa said the operation also plans to partner with a third party to build an LNG plant near the mine to ensure a sustainable supply.

Ora Banda’s Davyhurst gold mine restart to be powered by LNG

Cat’s DGB dual-fuel technology cuts costs, emissions at La Herradura gold mine