Cabral Gold Announces New Mineral Resource Estimate for the Cuiú Cuiú Project, Brazil
Cabral Gold Announces New Mineral Resource
Estimate for the Cuiú Cuiú Project, Brazil
Vancouver, British Columbia--(Newsfile Corp. - September 30, 2022) -
Cabral Gold Inc. (TSXV: CBR)
(OTC Pink: CBGZF) ("Cabral" or the
"
Company
") is pleased to announce an updated Mineral
Resource Estimate for the Cuiú Cuiú project, Para State, Brazil.
Highlights:
Total Indicated Resources are 21.6 M tonnes grading 0.87 g/t gold (604.0 K ounces), while total Inferred
Resources are 19.8 M tonnes grading 0.84 g/t gold (534.5 K ounces). All Indicated Resources and 84%
of the Inferred Resource (ounces) are contained within the MG and Central/CN deposits. Indicated
Resources increased by 433 K ounces (253%) from the previous estimate
Open-pit Indicated Resources amenable to mill processing are 21.6 M tonnes grading 0.87g/t gold
(604.0 K ounces), while open-pit Inferred Resources are 17.2 M tonnes grading 0.68 g/t gold
(376.9 K ounces)
Open-pit oxide resources amenable to heap-leach processing are reported for Central/CN, MG,
and PDM, comprising Indicated Resources of 9.3 M tonnes grading 0.52 g/t gold (153.7 K
ounces), and Inferred Resources of 6.1 M tonnes grading 0.40 g/t gold (79.2 K ounces)
All of the deposits included in the current Mineral Resource Estimate remain open along strike and
down dip of the resource estimate wireframes. The deepest drill holes returned positive results and
there are no known geological structures that could interrupt, or constrain the mineralization below
the current wireframes
New discoveries at Machichie and MG have not yet been sufficiently drilled for inclusion in a
resource estimate
Alan Carter, Cabral's President and CEO commented, "The new resource estimate is a testament to
the integrity of the Cuiú Cuiú mineralization, with more than 50% of the total gold ounces in the
indicated category. Our geological understanding has improved significantly since Cabral
commenced
drilling and the Company is now able to correlate, interpret and predict gold
mineralization down dip and along strike. The definition of the first near-surface heap-leachable oxide
Mineral Resource (154 K ounces Indicated and 79 K ounces Inferred) could be a game changer for
early low-cost development of a mine at Cuiú Cuiú, supported by our approved Trial Mining Licenses.
Future drill programs will focus on step-out drilling aimed at increasing resources at Central and MG
and maiden resources for the Machichie and PDM discoveries".
This is the first resource estimate incorporating Cabral's drilling data since the Company commenced
drilling at the Cuiú Cuiú project in 2019. The Company had originally planned on issuing an updated
Mineral Resource Estimate at the end of 2022 following completion of deeper down-dip and on-strike
drilling at known deposits, and completion of drill programs at two exciting new discoveries (PDM and
Machichie), all of which was designed to increase the overall resource. The current Mineral Resource
Estimate was, however, completed months earlier than planned, due to a request by the British
Columbia Securities Commission to update the existing NI 43-101 technical report (effective date of
June 19, 2021) that had been referenced in both the Annual Information Form dated May 5, 2022, and
the preliminary short-form prospectus filed on May 25, 2022. The Company was placed on the defaulting
issuer list on September 15, 2022, pending completion, filing and review of the 2022 NI 43-101 technical
report.
Despite the change in timing, the current Mineral Resource Estimate reflects a significant advancement
of the project with drilling undertaken through the Effective Date (July 31, 2022) which was designed
primarily to infill previous drilling at MG and Central, as well as to identify and expand newly discovered
gold-in-oxide mineralized zones at MG, PDM and Central, and primary basement mineralization at
Machichie and PDM. This drill program was successful in meeting those objectives. Cabral drilling to the
Effective Date also clarified historical work, and significantly improved the degree of confidence and
understanding of the mineralized zones at MG and Central as illustrated by the 253% increase in
Indicated Resources from previous estimates.
Planned deeper and step-out drilling that had been designed to expand resources at several deposits,
was not completed prior to the database cut-off date for the current Mineral Resource Estimate.
Similarly, additional drilling will be required at the PDM and Machichie discoveries to enable future
inclusion in the current resource.
Figure 1: Location of current gold resources at Central/CN, JB, MG and PDM oxide deposit. The
locations of new discoveries in primary basement rocks at Machichie and PDM are also shown
To view an enhanced version of Figure 1, please visit:
https://images.newsfilecorp.com/files/3900/138997_1612eddd64127a86_002full.jpg
2022 SLR Resource Estimate
The current Mineral Resource Estimate, effective July 31, 2022 (Table 1) was prepared by SLR
Consulting (Canada) Ltd. ("
SLR
") and disclosed in accordance with National Instrument 43-101 ("
NI 43-
101
"). The estimate is based on drilling undertaken by Cabral prior to July 31, 2022, as well as historic
drilling by Magellan Minerals Ltd. ("
Magellan
"), the former owner of the Cuiú Cuiú project, from 2006
through 2012.
Wireframes used to constrain block estimates were completed by Cabral and SLR using Surpac,
Discover 2021, and Leapfrog Geo.
Wireframes for low grade, high grade, saprolite and blanket material
were generated.
Assays were capped to various levels prior to compositing to a 2.0m length.
Wireframes were filled with blocks measuring 5m by 2m by 5m in each direction and sub-celled along
wireframe boundaries. The block models were re-blocked to 10m by 4m by 10m for pit optimization
purposes, although reporting of open-pit resources was performed on re-blocked 5m by 2m by 5m
blocks. Underground resources were reported based on sub-cells within underground reporting shapes
generated using the Deswik Stope Optimizer ("
DSO
"). Densities were assigned based on weathering
zones and mineralization shells. Blocks grades were interpolated using Inverse Distance Cubed ("
ID3
").
Blocks were classified as Indicated and Inferred in accordance with CIM Definition Standards (2014).
Indicated Mineral Resources were defined by drilling spaced up to 50m apart while Inferred Mineral
Resource were defined by a maximum extrapolation distance of 100m. The block estimates were
validated using industry standard techniques such as visual inspection, global mean bias checks and
swath plots.
This is the first Cuiú Cuiú resource estimate to incorporate results from Cabral's drill programs which
commenced in 2019. In addition to subdividing open pit and underground mineralization, this new
Mineral Resource Estimate is also the first to segregate gold-in-oxide blanket and weathered saprolite
oxide mineralization, both of which may be amenable to low-cost heap-leach processing, from fresh
basement mineralization, which will require conventional milling and processing.
The 2022 Mineral Resource Estimate incorporates gold mineralization from five deposits (Figure 1),
namely Central, MG, JB, CN, and PDM. The geology was reinterpreted and new wireframe models were
developed for each deposit.
Total Indicated and Inferred Resources
The total Indicated Resource is 21.6 M tonnes grading 0.87 g/t gold (604.0 K ounces), while the total
Inferred Resource is 19.8 M tonnes grading 0.84 g/t gold (534.5 K ounces), representing 53% and 47%
of the reported ounces, respectively.
Most of the resource is attributable to the MG and Central deposits. All of the project's Indicated
Resources occur within open pits designed for the MG and Central deposits, while 83% of the total
Inferred Resource is contained within the MG and Central/CN deposits.
Open Pit vs Underground Resources
Open-pit resources are included for Central, MG, CN, JB, and PDM. These comprise an Indicated
Resource of 21.6 M tonnes grading 0.87 g/t gold (604.0 K ounces), all of which occur at MG and Central,
and an Inferred Resource of 17.2 M tonnes grading 0.68 g/t gold (376.9 K ounces).
All mineralization amenable to underground mining is fresh unweathered basement mineralization and
has been allocated to Inferred Resources, comprising 2.6 M tonnes grading 1.92 g/t gold (157.6 K
ounces). These underground zones, all of which are open at depth, occur beneath the pit limits at
Central, MG, and JB, which respectively represent 47%, 42% and 11% of the underground Inferred
Resources.
Oxide and Fresh Basement Resources
Open pit oxide resources amenable to heap-leach processing are reported for Central, MG, CN and
PDM, comprising an Indicated Resource of 9.3M tonnes grading 0.52 g/t gold (153.7 K ounces), and an
Inferred Resource of 6.1 M tonnes grading 0.40 g/t gold (79.2 ounces). All of the oxide Indicated
Resources are from Central and MG, while 72% of the Inferred Resources are from the Central/CN and
MG deposits.
Oxide resources can be further subdivided into weathered basement saprolite and unconformably
overlying colluvial/fluvial blanket mineralization. The latter are unconsolidated eroded saprolite
mineralization, extend from surface, and are expected to be entirely free digging.
Blanket mineralization
include 4.1 M tonnes grading 0.37 g/t gold (47.6 K ounces) of Indicated Resources at MG and Central,
and 3.8 M tonnes grading 0.35 g/t gold (43.3 K ounces) of Inferred Resources at Central, MG and PDM.
Fresh basement open-pit and underground mineralization remain the bulk of the resources, and both will
require conventional milling and processing. These are reported for Central, MG, CN and JB, and
comprise an Indicated Resource of 12.3 M tonnes grading 1.14 g/t gold (450.3 K ounces) and an
Inferred Resource of 13.6 M tonnes grading 1.04 g/t gold (455.2 K ounces).
OP/UG
Category
Zone
Deposit
Tonnage
(Mt)
Au (g/t)
Au (koz)
Open Pit
Indicated
Blanket
Central/CN
1.07
0.38
13.1
MG
2.99
0.36
34.5
Sub-Total
4.05
0.37
47.6
Saprolite
Central/CN
2.42
0.67
52.3
MG
2.79
0.60
53.8
Sub-Total
5.21
0.63
106.1
Oxide
Total
9.26
0.52
153.7
Fresh
Central/CN
7.50
0.91
219.9
MG
4.79
1.50
230.3
Sub-Total
12.29
1.14
450.3
Total OP Indicated
21.56
0.87
604.0
Inferred
Blanket
Central/CN
1.33
0.28
12.0
MG
0.91
0.31
9.2
PDM
1.60
0.43
22.1
Sub-Total
3.84
0.35
43.3
Saprolite
Central/CN
2.03
0.50
32.8
MG
0.28
0.35
3.1
Sub-Total
2.30
0.49
36.0
Oxide
Total
6.15
0.40
79.2
Fresh
Central/CN
8.47
0.91
247.5
MG
0.33
0.57
5.9
JB
2.29
0.60
44.2
Sub-Total
11.08
0.84
297.6
Total OP Inferred
17.23
0.68
376.9
Underground
Inferred
Fresh
Central/CN
1.23
1.88
74.3
MG
0.99
2.08
65.8
JB
0.34
1.62
17.4
Sub-Total
2.55
1.92
157.6
Total UG Inferred
2.55
1.92
157.6
Total Indicated
21.56
0.87
604.0
Total Inferred
19.78
0.84
534.5
Table 1: Summary of the SLR 2022 Mineral Resource Estimate segregated by mining method,
resource category, weathering type, and mineral deposit.
SLR Notes:
1
.
CIM (2014) definitions were followed for Mineral Resources.
2
.
Mineral Resources are estimated at a cut-off grade of 0.26 g/t Au for open-pit fresh-rock
mineralization, 0.14 g/t Au for blanket mineralization and saprolite, and 1.15 g/t Au for underground
fresh-rock mineralization.
3
.
Mineral Resources are estimated using a long-term gold price of US$1,800 per ounce.
4
.
Open pit and underground Mineral Resources are reported within a conceptual open pit and within
underground constraining shapes for material below the pit.
5
.
All blocks within underground constraining shapes have been included in the Mineral Resource
estimate.
6
.
Minimum widths are 2 m for open pit and 1.5 m for underground.
7
.
Bulk density is 1.86 t/m
3
for Central/CN saprolite and 2.69 t/m
3
for Central/CN fresh, 1.60 t/m
3
for
MG saprolite and 2.76 t/m
3
for MG fresh, 2.66 t/m
3
for JB fresh, and 1.91 t/m
3
for PDM saprolite.
8
.
Metallurgical recovery used is 82% for saprolite/blanket material, and 90% for fresh rock.
9
.
Numbers may not add due to rounding.
10
.
Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability.
Comparison with Historic and Previous Resources
The previous estimate for the Cuiú-Cuiú project was effective as of June 7 , 2018, which remained
unchanged in the last NI 43-101 Technical Report filed on SEDAR.
The main differences between the previous and current estimates are listed below.
•
A 266% increase in Indicated tonnage and a 253% increase in Indicated ounces
•
First time estimation of Inferred Mineral Resources for oxide mineralization at PDM totaling 1.6 M
tonnes at a grade of 0.43 g/t (22.1 K ounces)
•
Reporting of 15.4 M tonnes at a grade of 0.47 g/t Au (233 K ounces) which are amenable to heap
leaching. This material includes blanket colluvium material and oxidized basement mineralization which
was previously not distinguished within the resource model.
The aforementioned differences can be attributed to the following:
•
Additional drilling at Central/Central North andMG resulting in the significant upgrade of Inferred to
Indicated and the addition of oxide mineralization at the PDM deposit to the Mineral Resource Estimate.
•
Remodeling and changes to estimation parameters, including:
Modelling of oxide blanket and saprolite.
Modelling of distinct high-grade domains.
Higher capping grades used due to the restrictive domaining methodology adopted.
•
Changes to the cut-off grades. The previous Mineral Resource estimate used cut-off grades of 0.35g/t
Au for open pit and 1.3 g/t Au for underground.
The updated cut-off grades were 0.14 g/t Au for open pit
saprolite and blanket material, 0.26 g/t Au for open pit fresh rock and 1.15 g/t Au for underground.
Reasons for these changes include:
Lower mining, G&A and processing costs used for blanket and saprolite zones.
Change in the recovery due to updated metallurgical test work.
Increased metal prices.
Lower mining, processing and G&A costs for fresh rock.
•
Use of a re-blocked block model for open-pit resource reporting.
•
Use of underground stope optimization and sub-celled blocks for underground reporting.
Cuiú Cuiú Drilling Program - Changes in Methodology and Resource History
A historic estimate was prepared by Pincock, Allen and Holt ("
PAH
") on behalf of Magellan in 2011. A
previous estimate was prepared for Cabral by Micon International Limited ("
Micon
") in 2018 as part of
the Cabral RTO.
The historic estimate was based on diamond drilling conducted by Magellan from 2006
through 2011, whilst the previous estimate was based on diamond drilling conducted by Magellan from
2006 through 2012.
There were numerous technical issues identified in the inherited drill and geological database used in
both the historic and previous resource estimates. The following three are most notable.
1
.
Magellan's historic drilling was very wide spaced and many of those older holes are now
recognized to have been drilled down dip and along strike. Historic horizontal drill-hole collars were
located using chain and compass and were not surveyed. Elevations for drill-hole collar locations
were determined using topographic maps. Combined, this yielded a poor understanding of the
geometry, lack of vertical and horizontal continuity, and an overall misinterpretation of the
disposition of gold mineralization, particularly higher-grade intercepts which could not be
correlated either from hole to hole, or down dip.
2
.
Much of the historic drilling was deep, and very few drill holes intersected near-surface oxide gold
mineralization that extends to depths greater than 80m. As a result, basement mineralization was
extrapolated to surface through undrilled saprolite.
Conversely, where there were some drill holes
that intersected shallow gold mineralization in the saprolite, this was interpreted as weathered
basement mineralization and was extrapolated to depth.
3
.
Magellan completed too few density measurements to be relevant for either the PAH or Micon QPs
to use, thus earlier resource estimates for basement and saprolite were entirely based on
published global rock densities, rather than representative drill core sample measurements.
Cabral modified its drill and sampling programs to address these technical issues.
1
.
Drill-hole spacing was tightened. Precise GPS was used to survey new drill holes and resurvey the
historic drill-hole collars. Historic collar co-ordinates were found to be up to 35m from true
locations, both vertically and horizontally. Repositioning collar locations and tightening drill-hole
spacing resulted in far better correlation and predictability of mineralization, horizontally and down
dip, particularly for higher-grade gold intercepts.
2
.
Shallow drill holes were designed to test the up-dip extensions of mineralization within weathered
and oxidized saprolite. These holes confirmed that fresh basement mineralization does extend into
the saprolite weathered profile, but also resulted in the discovery of a shallow sequence of
unconformable eroded and transported colluvial/fluvial gold deposits (blanket) overlying
saprolitized basement. Basement intercepts cannot be extended up dip through this unconformity,
nor can mineralized unconformable colluvial intercepts be interpreted to extend down dip. A
number of zones interpreted to extend into basement from such intercepts in historic resource
estimates did not exist, and were instead part of a sub-horizontal mineralized colluvial blanket.
Offsetting this were a number of new footwall and hanging-wall basement zones discovered during
the drilling, in addition to improved lateral and vertical continuity.
3
.
Cabral implemented systematic density measurements, resulting in more realistic estimates of the
tonnage within the resources.
Since acquiring the Cuiú Cuiú project at the end of 2017, the Company has identified numerous new
targets. Drill programs from 2019 to July 31, 2022 were designed primarily to qualify, quantify and
improve the understanding of gold deposits incorporated in earlier resource estimates, while also
advancing and evaluating new gold discoveries.
Drilling in historic resources was relatively shallow and largely confined to existing resource areas. The
Company's focus was to better define and understand the larger two deposits, Central and MG. Cabral
has not yet drilled any holes at JB or CN, the two smaller deposits included in the previous 2018
resource estimate.
Most of the new discoveries have only been tested with a few shallow scout holes to date, and are not yet
adequately drilled on strike or down dip to warrant a resource estimate at this time.
Machichie and PDM
are the two most advanced examples and are discussed in the following two paragraphs as examples.
The most advanced new discoveries on the project to date occur within the Machichie complex, where
many new zones have been identified over a broad region, including the Machichie Main zone,
Machichie West, Machichie NE and the Machichie SW vein array.
However, drilling remains wide
spaced and shallow. Moreover, mineralization at the Machichie Main Zone has been recently extended
over 300m by trenches and that area has not yet been drill tested. Additional drilling at Machichie will be
required before a resource estimate is warranted. Machichie is also intriguing as it has visible
molybdenum and scheelite mineralization at surface and in drill core and is associated with a historic IP
anomaly and tungsten-molybdenite-copper-gold auger anomaly that is not yet fully explained.
At PDM, Magellan had encountered significant gold bedrock gold intercepts in a number of drill holes but
drilling was insufficient to establish either vertical or horizontal continuity. Cabral recognized a blanket of
mineralized transported colluvial cover above these basement intercepts, and drilled the entire area in a
grid of shallow RC holes testing the cover.
This drilling established an oxide zone that has been
incorporated into the current mineral resource estimate. Higher-grade northwest-trending gold zones
were recognized in the blanket, and diamond drilling below them identified steeply dipping northwest-
trending gold mineralization in the underlying fresh basement.
Historic intercepts had been drilled sub-
parallel to strike and down dip. Further drilling will be required to determine the size and continuity of the
new basement zones before a PDM basement resource estimate is justified.
All of the deposits included in the current Mineral Resource Estimate remain open on strike and down
dip of the resource estimate wireframes. The deepest drill holes still returned positive results and there
are no geological structures that could interrupt, or constrain the mineralization below the current
wireframes.
Future Plans and Programs
The Company now has a firm handle on the geometry and orientation of mineralized zones for future drill
hole planning and targeting as a result of the recently completed drill program. Planned deeper and step-
out drilling that had been designed to expand resources at several deposits was not completed prior to
the database cut-off date for the current Mineral Resource Estimate. Similarly, systematic drilling at
several advanced new discoveries had not sufficiently advanced to warrant inclusion in the current
Mineral Resource Estimate.
This drilling is now expected to be undertaken in the next phase of the drill
program.
Future drill programs will focus on increasing resources while improving grade.
About Cabral Gold Inc.
The Company is a junior resource company engaged in the identification, exploration and development
of mineral properties, with a primary focus on gold properties located in Brazil.
The Company has a
100% interest in the Cuiú Cuiú gold district located in the Tapajós Region, within the state of Pará in
northern Brazil. Two main gold deposits have so far been defined at the Cuiú Cuiú project which contains
43-101 compliant Indicated resources of 21.6Mt @ 0.87 g/t (604,000 oz) and Inferred resources of
19.8Mt @ 0.84 g/t (534,500oz).
The Tapajós Gold Province is the site of the largest gold rush in Brazil's history producing an estimated
30 to 50 million ounces of placer gold between 1978 and 1995. Cuiú Cuiú was the largest area of placer
workings in the Tapajós and produced an estimated 2Moz of placer gold historically.
FOR FURTHER INFORMATION PLEASE CONTACT:
"Alan Carter"
President and Chief Executive Officer
Cabral Gold Inc.
Tel: 604.676.5660
Guillermo Hughes, MAusIMM and FAIG., a consultant to the Company as well as a Qualified Person
as defined by National Instrument 43-101, supervised the preparation of the technical information in
this news release.
The Mineral Resource estimate was prepared by Mr. Renan Garcia Lopes, MAusIMM CP(Geo.),
Associate Consultant Geologist at SLR Consulting Ltd., based in Belo Horizonte, Minas Gerais State,
Brazil. Mr. Lopes is an Independent Qualified Person as defined by NI 43-101. Mr. Lopes has read
and approved the contents of this news release, as it relates to the disclosed Mineral Resource
Estimate.
Neither the TSX Venture Exchange nor its Regulation Services Provider (as such term is defined in
the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this
release.
Forward-looking Statements
This news release contains certain forward-looking information and forward-looking statements within
the meaning of applicable securities legislation (collectively "forward-looking statements").
The use of
the words "will", "expected" and similar expressions are intended to identify forward-looking
statements.
These statements involve known and unknown risks, uncertainties and other factors that
may cause actual results or events to differ materially from those anticipated in such forward-looking
statements.
Such forward-looking statements should not be unduly relied upon.
This news release
contains forward-looking statements and assumptions pertaining to the following:
strategic plans and
future operations, and results of exploration. Actual results achieved may vary from the information
provided herein as a result of numerous known and unknown risks and uncertainties and other factors.
The Company believes the expectations reflected in those forward-looking statements are
reasonable, but no assurance can be given that these expectations will prove to be correct.
Notes
Gold analysis has been conducted by SGS method FAA505 (fire assay of 50g charge), with higher
grade samples checked by FAA525. Analytical quality is monitored by certified references and
blanks. Until dispatch, samples are stored under the supervision the Company's exploration office.
The samples are couriered to the assay laboratory using a commercial contractor. Pulps are returned
to the Company and archived. Drill holes results are quoted as down-hole length weighted
intersections.
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