VANCOUVER, BC, Aug. 3, 2021 /CNW/ - Trevali Mining
Corporation ("Trevali" or the "Company") (TSX: TV) (BVL:
TV) (OTCQX: TREVF) (Frankfurt:
4TI) in pleased to announce that 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, is underway. 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.
Highlights
- Leach test program targets an improvement to zinc, lead,
copper, gold, and silver metal recoveries.
- 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.
- Opportunity to process historic mill tailings, which include
gold and copper metals, in addition to run of mine ore, increasing
revenues and reducing closure liabilities.
- Potential to reduce Trevali's carbon footprint at Caribou.
- Potential to extend Caribou's mine life and treat lower-grade
deposits in the Bathurst
camp.
- A successful pilot plant test program is expected to support
future study work on a Preliminary Economic Assessment and
NI-43-101 Technical Report which includes potential processing of
the Trevali mill feed and mill tailings and production of metal on
site.
If the pilot plant testing program indicates that the ROL
technology has the potential to be successfully implemented at
Caribou, it 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. The initiative is consistent with
Trevali's strategy to extend the two-year mine plan and investigate
further longer-term value-enhancing opportunities in the Bathurst
Mining Camp. In addition, the technology has the potential to
reduce the Company's carbon footprint and provide other sustainable
environmental benefits via the re-treatment and disposal of
tailings.
Conceptual objectives of the program include:
- Recovery of metals/minerals that are not recoverable utilizing
the current technology at Caribou (precious metals and
magnetite)
- Improved payables/selectivity of the traditional flotation
process utilizing new and emerging technologies
"FLSmidth's Rapid Oxidative Leach metallurgical technology has
the potential to transform the Caribou mine and the wider Bathurst
Mining Camp. If viable at Caribou, the technology may increase
metallurgical recoveries, produce precipitate or metal on site,
including copper and gold, and reduce or eliminate freight costs
and treatment charges related to concentrate. 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," commented Ricus
Grimbeek, President and Chief Executive Officer of Trevali. "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.
Background
A simplified Caribou flowsheet is shown in Figure 1. Depending
on the composition of the ore feed, zinc, lead and silver are
recovered in the mill to zinc and lead concentrates at a rate of
approximately 78% zinc, 62% lead and 25% silver, respectively. The
concentrates are then shipped to a smelter to convert to metal.
Trevali is responsible for paying treatment charges to third party
smelters as well as other associated costs in connection with the
transport to, and recovery of metals at, the smelter.
Figure 1: Simplified Caribou Flowsheet Currently In
Use
To improve performance and economics, the Company has reviewed
several processes that have been conceived and decided to test the
ROL Technology. The ROL technology, patent pending by FLSmidth, is
a mechano-chemical approach pursuant to which (as described in more
detail below) impacting the mineral particle supplies energy to
abrade the surface of the leaching particle, increasing the
chemical reaction rate as well as removing reaction products from
the surface, thus improving the rate of reaction.
Process Description
FLSmidth's patent-pending ROL process utilizes a stirred media
reactor to achieve improved metal recoveries under atmospheric
conditions within a reasonable amount of time. This
mechano-chemical approach overcomes many of the surface passivation
problems that have hindered other atmospheric leach processes. The
process takes advantage of the enhanced reactivity of transitory,
surface-defect structures generated during particle fracture. The
process occurs at 80-90 °C and under atmospheric pressure. The use
of very low energy, inter-stage attrition/grinding is used to
enhance the selective dissolution of valuable minerals.
Rapid Oxidative Leach Benefits
- Avoids the excessive production of sulphuric acid.
- Lowers the carbon footprint by reducing shipping volume.
- The process is scalable.
- Mechano-chemical stirred media reactors (SMRt) perform the
mechanical surface activation.
A comparison of alternative processes is summarized in Table
1.
Table 1: Leach Technology Alternatives
|
Rapid
Oxidative
Leach
|
Atmospheric
Leaching
|
Pressure
Leaching
|
Zinc recovery and
leach
kinetics
|
High recovery,
good
kinetics, modest size
reactors
|
Slightly lower
recovery,
slower kinetics, larger
reactors
|
High recovery,
faster
kinetics, smaller reactors
|
Flexibility and
process
control
|
Flexible, suitable
for variety
of grades and feed rates.
Enables Ag and Pb
recovery and full control of
iron precipitation. No
handling of molten sulphur.
Simple process control.
|
Flexible, suitable
for
variety of grades and
feed rates. Enables Ag
and Pb recovery and full
control of iron
precipitation. No handling
of molten sulphur.
|
Complicated
process
control (temperature,
molten sulphur, scaling
issues, leaching additives)
|
Need of
maintenance
and shutdowns
|
Low maintenance,
reliable,
no scale build-up, low
corrosion
|
Low maintenance,
reliable, no scale build-
up, low corrosion
|
High maintenance,
long
shutdowns, scale removal
|
Investment
costs
|
Low investment cost
due to
simplicity of tanks and
atmospheric operation and
good reaction kinetics.
|
Low investment cost
due
to simplicity of tanks and
atmospheric operation
|
High investment cost
due
to complexity, high-tech
metals, valves and controls
|
Operating
costs
|
Higher mixing power,
low
maintenance, no steam
required
|
Higher mixing power,
low
maintenance, no steam
required
|
Low mixing power,
high
maintenance, steam
heating
|
The improvement in leaching kinetics versus conventional
atmospheric leaching is due to the addition of the SMRt reactors in
the circuit. Figure 2 shows the relative scale of the SMRt reactors
versus the atmospheric leach vessels.
Figure 2: Relative Scale of Stirred Media Reactor (SMRt)
Versus Leach Vessels in the ROL Process
A simplified version of the conceptual flowsheet in Figure 3
shows how potential metal production on site would be accomplished
if the ROL Technology is implemented. There may also be options to
produce intermediary products such as metal precipitates, which
optionality is part of the studies in the current
program.
Figure 3: Possible Caribou Flowsheet Using Rapid Oxidative
Leach Technology
A Path Forward
Trevali has a foothold in the Bathurst Mining Camp, which is a
valuable and important mining region to New Brunswick and Canada. Infrastructure, mining innovations,
economic impact, social effects, and environmental initiatives
comprise a few of the reasons for the Camp's continuing
importance. Since 2000, mine closure and reclamation have
outpaced mine development in the Bathurst Mining Camp. Although at
a very early study stage, applying FLSmidth's ROL technology at
Caribou may provide an opportunity to begin a reversion of that
trend in an environmentally friendly and sustainable manner.
ABOUT TREVALI
Trevali is a global base-metals mining Company headquartered in
Vancouver, Canada. The bulk
of Trevali's revenue is generated from base-metals mining at
its four operational assets: the 90%-owned Perkoa Mine in
Burkina Faso, the 90%-owned Rosh
Pinah Mine in Namibia, the
wholly-owned Caribou Mine in northern New Brunswick, Canada and the wholly-owned
Santander Mine in Peru. In
addition, Trevali owns the Halfmile and Stratmat Properties
and the Restigouche Deposit in New
Brunswick, Canada, and the past-producing Ruttan Mine
in northern Manitoba, Canada.
Trevali also owns an effective 44%- interest in the Gergarub
Project in Namibia, as well as an
option to acquire a 100% interest in the Heath Steele
deposit located in New Brunswick, Canada.
The shares of Trevali are listed on the TSX (symbol TV), the
OTCQX (symbol TREVF), the Lima Stock Exchange (symbol TV), and
the Frankfurt Exchange (symbol 4TI). For further details on
Trevali, readers are referred to the Company's website
(www.trevali.com) and to Canadian regulatory filings on
SEDAR at www.sedar.com.
Cautionary Note Regarding Forward-Looking Information and
Statements
This news release contains "forward-looking information" within
the meaning of Canadian securities legislation and "forward-looking
statements" within the meaning of the United States Private
Securities Litigation Reform Act of 1995 (collectively,
"forward-looking statements"). In certain cases, forward-looking
statements can be identified by the use of words such as "plans",
"expects", "outlook", "guidance", "budget", "scheduled",
"estimates", "forecasts", "intends", "anticipates" or "believes",
or variations of such words and phrases or statements that certain
actions, events or results "may", "could", "would", "might", "will
be taken", "occur" or "be achieved" or the negative of these terms
or comparable terminology.
Forward-looking statements relate to future events or future
performance and reflect management's expectations or beliefs
regarding future events including, but not limited to, statements
with respect to the rapid oxidative leaching (ROL) pilot plant
testing program using Caribou run-of-mine milled material and the
potential outcomes and benefits of same, including but not limited
to improvements in zinc, lead, silver, gold and copper recoveries,
the potential to produce a precipitate or metal on site in
place of the current ore concentrate and any potential savings on
transport and offsite treatment costs resulting therefrom, the
ability to reduce the Company's carbon footprint at Caribou and
provide other sustainable environmental benefits, the opportunity
to treat and recover historic mill tailings, including gold and
copper values, in addition to run of mine ore, the potential to
extend the mine life at Caribou and to treat lower-grade deposits
in the Bathurst Mining Camp, and the ability of the pilot plant
testing program to generate engineering data to support future
study work on a preliminary economic assessment with respect to the
use of ROL technology at Caribou; the the ability of Trevali
to replace the existing flotation circuit at Caribou with
atmospheric leach vessels and potentially an SX/EW train; the
potential positive impacts on the Bathurst Mining Camp which may be
generated by the ROL technology, including the reversion of the
trend of mine closures in the Bathurst Mining Camp; the timing,
nature and scope of the planned pilot plant testing program; the
potential changes to the existing flowsheet at Caribou to give
effect to the implementation of ROL technology at Cariboo; and the
Company's growth strategies and planned development activities,
including the ongoing study work and any potential implementation
of the ROL technology at the Caribou mine. Forward-looking
statements are based on the beliefs, expectations, assumptions and
opinions of management of the Company as of the date the statements
are published, including, with respect to the forward-looking
statements in this news release, that the ROL pilot plant testing
program will be successfully completed on the timeline currently
anticipated; that the ROL technology can be implemented by Trevali
at the Caribou mine if the pilot plant testing program is
successful; that the ROL technology will generate the expected
benefits for Trevali and the Bathurst Mining Camp; that, if the ROL
technology is implemented at Caribou, it will be able to be
similarly implemented at other locations in the Bathurst Mining
Camp and will generate benefits at those locations; and that the
changes proposed to the existing flowsheet at Caribou will
correspond generally to any actual changes made to the Caribou
flowsheet arising from the pilot plant test program. By their very
nature, forward-looking statements involve known and unknown risks,
uncertainties and other factors which may cause the actual results,
performance or achievements of the Company to be materially
different from any future results, performance or achievements
expressed or implied by the forward-looking statements, including,
without limitation, risks related to the ROL pilot plant testing
program, including that the program may not be successful at
achieving some or all of its stated objectives; the risk that even
if the pilot plant testing program is successful, it may not be
feasible or economic to build a re-designed flowsheet at the
Caribou mine incorporating the ROL technology; the risk that the
re-designed flowsheet at the Caribou mine incorporating the ROL
technology, if implemented, will be different than currently
anticipated; the risk that the ROL technology, if implemented at
Cariboo, will not generate positive impacts on the Bathurst Mining
Camp more generally; the risk that the pilot plant testing program
will not proceed as currently anticipated on the timeline currently
anticipated, or at all; risks related to changes in project
parameters as plans continue to be refined, including with respect
to the Caribou life of mine; risks related to dependence on key
personnel; risks related to labour pool constraints; risks related
to labour disputes; risks related to the availability of
infrastructure required for the development of mining projects;
risks associated with delays or inability to obtain governmental
and regulatory approvals for mining operations or financing or in
the completion of development or construction activities;
counterparty risks; risks associated with increased operating and
capital costs; risks related to foreign currency exchange rate
fluctuations; risks associated with compliance with governmental
decrees and regulations, including any new or ongoing decrees and
regulations issued by a governmental authority in response to the
COVID-19 pandemic; risks related to compliance with environmental
laws and regulations; risks associated with land reclamation and
mine closure obligations; risks related to challenges to title or
ownership interest of our mineral properties; risks related to
maintaining the Company's ongoing social license to operate; risks
associated with the impact of climatic conditions on the Company's
mining operations; risks associated with compliance with debt
covenants; risks related to our ability to raise capital; risks
related to competition in the mining industry; litigation risks;
and other risks of the mining industry including, without
limitation, other risks and uncertainties that are more fully
described in the Company's annual information form, interim
and annual audited consolidated financial statements and
management's discussion and analysis of those statements, all of
which are filed and available for review under the Company's
profile on SEDAR at www.sedar.com. Although the Company has
attempted to identify important factors that could cause actual
actions, events or results to differ materially from those
described in forward-looking statements, there may be other factors
that cause actions, events or results not to be as anticipated,
estimated or intended. Trevali provides no assurance that
forward-looking statements will prove to be accurate, as actual
results and future events may differ from those anticipated in such
statements. Accordingly, readers should not place undue reliance on
forward-looking statements.
SOURCE Trevali Mining Corporation