Tag Archives: Caribou

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

3rd August 2021Base metals, Metallurgy, Mine operation news, Mineral processing, Mining services, Precious metals, Sustainable miningBathurst, Canada, Caribou, copper, FLSmidth, gold, lead, Rapid Oxidative Leach, Ricus Grimbeek, ROL, Silver, SX-EW, Trevali Mining, zincDaniel Gleeson

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 Mining and Redpath plot Caribou zinc-lead mine restart plan

15th January 2021Base metals, Mine operation news, Mining services, Precious metalsCanada, Caribou, Glencore, lead, New Brunswick, Redpath Mining, Ricus Grimbeek, Silver, Trevali Mining, zincDaniel Gleeson

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.”

MinePortal offers up an integrated view of mine site data

3rd December 2019Base metals, Comminution of minerals, Explosives and blasting, IoT, Mineral processing, Mining services, Mining softwarebig data, Caribou, DataCloud, Drill and blast, IoT, Krishna Srinivasan, MinePortal, Mines and Technology, New Brunswick, RHINO, Trevali Mining, zincDaniel Gleeson

DataCloud’s MinePortal solution has links to the ‘artificial intelligence’, ‘big data’ and ‘digitalisation’ buzzwords that are heard throughout the conference halls at any global technology conference today, but, unlike some of its competitors, the concept is very easy to understand.

Simply put, MinePortal collects existing datasets from within a mining company’s operation and aggregates that data into a model that shows the entire process – from drilling through to processing in the plant.

Technology-agnostic, it uses cloud computing to ingest and process this data in near real-time, applying the company’s proprietary geostatistical and machine learning algorithms to continually update models.

The fact it can look at the entire mining process – from end-to-end – makes it almost unique in the industry, according to DataCloud Chief Technology Officer, Krishna Srinivasan.

“Data is no longer the problem in mining,” he told IM on the side lines of the Mines and Technology conference in London last week. “What mines haven’t got is a place where all of this data is displayed together for analysis. This is what MinePortal brings.”

In addition to leveraging off a mine’s existing fleet management and condition monitoring platforms, it also uses its own RHINO blast hole measurement package on production drills to enhance geology data right from the source.

RHINO (below) uses vibration signatures in the drill steel, acquired via IoT-enabled sensor devices, to calculate blast-critical subsurface information such as compressional and shear moduli, compressive strength, density, velocity, and more. This can help detect waste boundaries, faults, fractures, and many grade indicators, according to the company. Once this data is recorded, it is streamed to MinePortal and analysed to characterise the orebody.

Srinivasan says the integrated visualisation capabilities MinePortal offers allows companies to find out where the obvious opportunities are to improve performance in their operations.

Such analysis could, for example, highlight that drill and blast patterns need to be amended to improve rock fragmentation for improved recoveries at the milling stage, or, conversely, milling needs to be tweaked to account for the increased hardness of ore coming into the plant.

It connects the dots between the various processes in mining and “provides the context” mining companies need to increase production and productivity, according to Srinivasan.

In addition to being able to visualise the mining process in an integrated fashion from anywhere in the world through the cloud, DataCloud’s geostatistical and machine learning algorithms can predict the processing outcomes should a site, for example, amend their drill spacing at the drill and blast stage.

Srinivasan was keen to stress these algorithms do not ‘take over’ a mine’s processing procedures, instead offering up estimates based on previous operating data and existing industry data MinePortal has analysed.

MinePortal has, until now, mostly been used as a visualisation tool at open-pit mines, but DataCloud recently signed an agreement with Trevali Mining to use the software on its Caribou underground zinc mine in New Brunswick, Canada.

DataCloud said of this agreement: “Unleashing MinePortal will provide vast feedback applications across the value chain empowering their teams to make geology data-driven decisions.”

This is part of the mining company’s wider plan to digitalise its operations through its T90 business improvement program. T90 is targeting $50 million in pre-tax annual sustainable efficiencies by the beginning of 2022 through “operational improvements, standardisation, and the deployment of technology”.

Outside of its work with Trevali, DataCloud is encouraging miners to get in touch for a customised demonstration of MinePortal’s capabilities to a mine site’s specific data, workflow and goals.

“Give us a year’s worth of data and we’ll display this in MinePortal for you,” Srinivasan said, explaining that the company is confident miners will be able to see areas for improvement through this visualisation and that it will lead to them engaging with DataCloud over a longer timeframe.