Tag Archives: Carlin Trend

El Nino arrives early for Premier, Nevada Gold Mines

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Premier Gold Mines says processing of ore has commenced from the El Nino gold mine at the joint venture South Arturo mine, in Nevada, USA.

South Arturo is located in the Carlin Trend, and is a joint venture between Premier (40%) and Nevada Gold Mines (60%), a joint venture company owned by Barrick Gold and Newmont-Goldcorp with Barrick as the operator.

The El Nino mine was developed on-time and on-budget, with ore now being processed ahead of schedule, according to Premier Gold. Production is expected to ramp up in the second half of 2019, with a first gold bar pour having been held on September 26.

Premier said attributable gold production is estimated to meet the high end of its 5,000-10,000 oz guidance for the year and it expects that, owing to the high-grade ore at El Nino, South Arturo will have a positive effect on cash flow for the company.

Ewan Downie, President and CEO of Premier, said: “We are excited to once again realise the benefits of South Arturo, increasing the company’s production profile with an anticipated reduction in overall operating costs. Premier continues to benefit from the stellar performance of our partner, Nevada Gold, and its demonstrated ability to consistently execute on schedule.”

In the second half of 2019, surface and underground drilling will resume in an effort to continue delineating and expanding mineralisation at El Nino. El Nino is a high-grade underground deposit situated down plunge of the Phase 2 pit, where mining was concluded in 2017. Pre-stripping of the Phase 1 open-pit project, a second mine being constructed at South Arturo, is ongoing with a target of production in the second half of 2020. Work is also continuing to optimise heap leach material with a potential future decision to proceed with the development of a heap leach facility on the property, the company said.

Surface haulage automation is being tested out at South Arturo, where ASI Mining has successfully completed a proof of concept (POC) utilising five haulage units “that have delivered over 5.5 Mt faster than any other similar POC in the industry”, Barrick Gold said last month.

Barrick cuts waste, boosts reserves from modified bench steepening at Goldstrike

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An alternative method of steeping the open-pit benchface at Barrick Gold’s Goldstrike mine in Nevada, US, has shown significant net benefits through a reduction in mined waste tonnes and an increase in gold reserves, according to a paper to be presented at the SME Annual Conference & Expo on Monday.

The paper, Steepening Of Inter-ramp Slopes On A Final Wall At The Goldstrike Open Pit, will be presented by Barrick Nevada’s Chief Geotechnical Engineer, Jeff Mattern.

Located on the Carlin Trend gold belt in north-eastern Nevada, the mine has produced over 43 Moz of gold during the past 30 years.  Mining at the Goldstrike open pit has seen its share of slope instabilities, according to Mattern. “In areas where slopes have remained stable, consideration has been made for potential slope steepening of final walls,” he said.

Looking to potentially employ steeper slopes for significant economic benefits, Barrick has taken the commonly used Modified Ritchie Criteria for catch bench width and adjusted it, “resulting in quantified, rock-specific formulas for bench width and rock fall berm placement”, Mattern said.

“The result is an interramp slope angle increase of 2° on a 300 m high slope, without the necessary purchases and procedural changes that would be required for pre-split drilling and blasting,” Mattern said. This occurs in Vinini, Rodeo Creek and Popovich rocks with benches 12 m in height.

The employment of this method has shown “significant” net benefits through a reduction in mined waste tonnes and an increase in gold reserves, he added. In fact, this exercise in a single layback, saw waste stripping decrease by around 9 Mt, while 35,000 oz of gold has been added to mine reserves.

Mattern concluded: “Ongoing monitoring of slope performance, slope design compliance, optimisation of operational practices, and collection of detailed geologic data can all help to provide the right information for potentially steeper slopes and significant economic benefit.”