Tag Archives: Ricus Grimbeek

Trevali to test out FLSmidth’s Rapid Oxidative Leach tech on Caribou material

Trevali Mining has announced the commencement of a pilot plant testing program using Caribou run-of-mine and milled material at FLSmidth’s Rapid Oxidative Leach (ROL) process testing facility in Salt Lake City, Utah.

The program expands on previous laboratory test work and is aimed at demonstrating the potential to recover zinc, lead, copper, gold and silver as a precipitate or metal and additional zinc and lead from Caribou ore and mill tailings.

The leach test program is targeting an improvement to zinc, lead, copper, gold and silver metal recoveries, the potential to produce a precipitate or metal on site replacing the current ore concentrate that is produced at Caribou – which, if implemented, would lead to savings on transport costs and offsite treatment costs – and the opportunity to process historic mill tailings, which include gold and copper metals, in addition to run of mine ore. The latter would increase revenues and reduce closure liabilities, Trevali said.

Trevali says the use of FLSmidth’s ROL technology also provides the potential to reduce Trevali’s carbon footprint at Caribou and extend Caribou’s mine life and treat lower-grade deposits in the Bathurst camp of Canada.

FLSmidth says ROL leaches 97-99% of copper directly on-site in six to eight hours, from concentrates as low as 5% Cu. In gold, ROL has the potential to unlock the value of undeveloped refractory gold deposits with less than 3 g/t gold head grade, it says.

Unlike other refractory processing techniques, the ROL process uses the application of mechanical energy coupled with oxidation under atmospheric conditions. The process relies on stirred media reactors to accelerate the oxidation of sulphide minerals. This eliminates the need for ultrafine grinding, high temperatures and high pressure which makes it energy saving and very cost-effective, according to the mining OEM.

Trevali said a successful pilot plant test program using ROL may allow Trevali to replace the existing flotation circuit at Caribou with atmospheric leach vessels and potentially an SX/EW train, introducing the possibility of producing base and precious metals on-site and thereby save transport costs and offsite treatment costs.

Conceptual objectives of the program include:

  • Recovery of metals/minerals that are not recoverable using the current technology at Caribou (precious metals and magnetite); and
  • Improved payables/selectivity of the traditional flotation process using new and emerging technologies.

Ricus Grimbeek, President and Chief Executive Officer of Trevali, said: “FLSmidth’s ROL metallurgical technology has the potential to transform the Caribou mine and the wider Bathurst Mining Camp.

“This next phase of the testing program is an essential step in evaluating the suitability and economic viability of a processing solution with the potential to enhance the value of the in-situ material and tailings at Caribou as well as the surrounding deposits in the Bathurst region. The positive results to date support further study and analysis given the potential implications for the Bathurst Mining Camp in general and Trevali in particular.”

Beyond quantifying the ability to recover additional metal values, the objective for the pilot plant test program is to determine the various kinetic factors, mass and energy balance and engineering data to support future engineering on a preliminary economic assessment for potential processing of the Trevali mill feed and mill tailings and produce metal on site.

Continuous pilot plant trials commenced in June 2021 (Phase 1) to tune the pilot plant and provide material for precious metal leach tests in late July, followed by a test program at the Caribou Mine site that is planned for September 2021 (Phase 2). Leach data and results are expected to verify that batch testing results can be achieved in a continuous operation.

Trevali taps EMESCO for solar power contract at Rosh Pinah mine

Trevali Mining has entered into a 15-year renewable Power Purchase Agreement with Emerging Markets Energy Services Company (EMESCO) for the supply of solar power to its Rosh Pinah zinc-lead-silver mine in Namibia.

Trevali has committed to achieving an overall greenhouse gas emission reduction target of 25% by 2025 from its 2018 baseline, with the PPA anticipated to deliver 30% of Rosh Pinah’s power requirements during the life of the agreement and reduce GHG emissions at the company level by 6%.

EMESCO will be responsible for the design, permitting, financing and implementation of a solar energy system on a neighbouring property at no cost to Trevali. EMESCO will then sell the power generated to Trevali at a fixed rate that is expected to reduce energy costs by 18% over the 15-year term of the agreement.

EMESCO was chosen based on a variety of factors, including expertise in the field of renewable energy, an understanding of the scope of work required, the ability to execute and deliver on Trevali’s requirements, and pricing, the miner said.

If Trevali makes a positive investment decision on the RP2.0 expansion project, which could see output rise to 3,600 t/d from 2,000 t/d, EMESCO will increase the delivery of power to Rosh Pinah to remain at 30% of the mine’s annual energy consumption as regulated by the Modified Single Buyer framework in Namibia, it added.

Ricus Grimbeek, President & CEO, said: “Our sustainability program commits to significant reductions in GHG emissions, and with the signing of this agreement with EMESCO we have taken a major step towards delivering on our commitment by securing renewable energy while also reducing our expected energy costs.

“The agreement with EMESCO has been designed to scale with the output of the mine so that when we are ready to make the decision to build the RP2.0 Expansion project, the delivery of power will increase to match our requirements.

“We are extremely excited by this partnership at Rosh Pinah and continue to study ways to reduce Trevali’s GHG emissions and deliver on this and our other sustainability targets.”

Trevali Mining and Redpath plot Caribou zinc-lead mine restart plan

Trevali Mining has enlisted the help of Redpath Mining to restart its Caribou zinc-lead mine near Bathurst, New Brunswick, Canada.

The mine has been on a care and maintenance program since March 2020 following a deterioration of the global zinc market and the continued challenges presented by COVID-19.

Armed with the implementation of several operational and commercial enhancements, as well as improved zinc market conditions, the company now expects to return to mining in early February, with first payable zinc production expected by the end of March.

Following ramp-up in 2021, the all-in sustaining cost (AISC) for Caribou is forecast to be between $0.84-$0.90/Ib of zinc in 2022. The AISC for 2021 is expected to be $0.91-$0.97/Ib.

This cost performance will be supported by a partnership with Redpath Mining as underground mining contractor at Caribou. Trevali says Redpath’s operational experience will help it safely and efficiently mine Caribou’s narrow mineralisation, with the company able to mobilise people and equipment quickly.

Also supporting the restart plan is the signing of a 21-month fixed pricing arrangement for a significant portion of the forecasted zinc production from the mine. Pursuant to existing offtake agreements, an affiliate of Glencore has agreed to purchase 115 Mib of payable zinc, which represents some 80% of the forecasted zinc production from Caribou, at an average price of $1.25/Ib.

These agreements are for the period from March 2021 to December 2022 and are in addition to Trevali’s existing hedging program, which covers the period from October 2020 to December 2021.

Trevali said it was also looking to enter into fixed-pricing arrangements for both lead and silver at meaningful levels of forecasted production from Caribou.

Production guidance for 2021 is estimated at between 60-65 Mib of payable zinc, 21-23 MIb of payable lead and 585,000-650,000 oz of payable silver. Zinc payable production is expected to increase to 72-77 MIb of payable zinc in 2022 as the mine receives the benefit of a full year of production.

During the initial 21-month operating period, Trevali says it will also continue to study metallurgical and operational opportunities to extend the current two-year mine plan, as well as other longer-term value enhancing initiatives in the Bathurst mining camp.

Ricus Grimbeek, Trevali’s President and CEO, said: “Our team has worked diligently to reduce the overall cost structure of the Caribou mine, and I am pleased that we are in a position to restart mine operations in a manner that we expect will generate positive cash flow.

“Our initial two-year plan includes several enhancements which are designed to improve the mine’s economics, including the involvement of a contracted mining operator and the entry into fixed-pricing arrangements for a significant portion of the mine’s forecasted production. We have benefited from the engagement of the provincial government, and with the recall of employees and the restart of production we look forward to being a more significant part of the New Brunswick economy.”