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Earlier today, Bonterra
Resources (BTR.V) released the
long-awaited results from its preliminary metallurgical test work
on samples from its high grade Gladiator Gold Deposit in
Québec.
Completing metallurgical studies are a very important milestone in
the development process of a gold project. You can have as much
gold as you want in a resource in the ground, but if you can’t get
it out of the rock easily, it really is just a bunch of worthless
rock. So….. one of the biggest de-risking mechanisms for any gold
mining project, is being able to extract the gold easily from the
rock through good metallurgical processing parameters, and to
recover as much gold with as little effort, capital and ongoing
operating costs as possible. This sometimes can the key component
in order to justify the economics of pushing a project towards a
construction or production decision, to generate a profit.
To start off, the Gladiator deposit yielded up to 76.1%
recovery in the gravity circuit, and on average for all
grinding sizes (coarser to fine) yielded greater than 70% gravity
recovery. This confirmed the presence of a significant
amount of free gold in the mineralized system. And that’s
exceptional when compared to its peers across Canada / USA, as most
‘competitors’ reported average gravity recovery rates of 15% to
40%. Noting that all tested grinding sizes yield excellent gravity
recoveries, it will allow for some flexibility when designing the
crushing and grinding circuits. This could potentially save
Bonterra an important part of its initial capex, but it coult also
allow the company to reduce its operating expenses.
On average, greater than 70% of the
gold reports to the gravity circuit at all grinding sizes, which
potentially contributes to substantial capital reductions in the
grinding circuits, potential lower reagent consumption, and
highlights an opportunity for significant savings in the future
processing parameters at Gladiator,”
Peter A. Ball, VP Operations.
To add to the excellent gravity
recoveries, total recovery results were also well worth the wait as
the combination of gravity and gravity-tail flotation tests
resulted in a recovery rate of around 97%. The final icing on the
cake, if even needed, the tests using gravity and
gravity-cyanidation indicated the recovery rate could exceed
99%.
Not only are these amazing results (for both processing scenarios),
there also is one important piece of information to harvest from
these results. The difference between the recovery rates of the
flotation circuit and the cyanide circuit is just 2%, which means
Bonterra will have to do some trade-off studies to figure out if a
cyanide leaching circuit would even make sense.
“Potentially not requiring a cyanide
leaching circuit minimizes the environmental footprint of any
future mining operation and could also improve potential
future process economics of the project,”
Nav Dhaliwal, CEO of Bonterra
We don’t think Bonterra will put in the
cyanide circuit as the NPV8% of a 150,000 oz/year production
scenario wherein 2% more gold (3,000 oz/year) would be recovered
would be just C$22M, based on a gold price of C$1700/oz. This means
that if a cyanidation circuit would cost more than C$22M, Bonterra
might be better off by just going for a flotation circuit as
recovering less gold might actually result in a higher net present
value. Of course, a final decision will only be made once Bonterra
has all parameters as everything will depend on the total size of
the resource and the expected average production rate (as well as
the access to capital).
Another interesting fact is that the “Feed Grade” head assay
results from the metallurgical testing ranged from 8.0 g/t Au to
10.0 g/t Au and showed excellent grade reconciliation with initial
drill hole assays.
Considering Bonterra’s gravity and total recovery rates are easily
beating the results from some peers in Canada and USA (see the
table below, note, these results are rounded and not necessarily
definitive), we dare to say these preliminary metallurgical results
are absolutely excellent.
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These results are extremely important as
they confirm the excellent “clean rock” characteristics of the
deposit, and the very low sulphide content such as arsenopyrite,
which some of their neighbours have in their gold systems.
Considering this is the very first time Bonterra has released any
recovery rates of the Gladiator gold ever, this update should ease
the concerns some investors might have. Not only is the gold
recoverable, the actual recovery rates are exceptionally high,
whilst the high gravity concentrate recovery rate indicates the
ultimate processing cost (in dollars per tonne) will reside in the
lower quartile compared to its peers.
The company is currently aggressively drilling the property as part
of an ongoing 70,000 meter exploration program to increase the
total gold resource at Gladiator. A resource update is expected for
the second half of this year and that will be the second major
component of a PEA which could be expected shortly thereafter.
Bonterra Resources is slowly ticking all the boxes in its quest to
build Québec’s next gold mine.
Click here to access Caesar’s
Report.
Go to Bonterra's Website.
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