GR Silver Mining Announces Completion of Initial Resource Estimates at the Plomosas Project in Sinaloa, Mexico
GR Silver Mining Announces Completion of
Initial Resource Estimates at the Plomosas
Project in Sinaloa, Mexico
VANCOUVER, BC
,
Aug. 23, 2021
/CNW/ -
GR Silver Mining Ltd.
(
"GR
Silver Mining"
or the
"Company"
)
(TSXV: GRSL) (OTCQB: GRSLF) (FRANKFURT: GPE) – today announced the
delivery of initial NI 43-101 mineral resource estimates on the Company's Plomosas Project
("Plomosas"), located in
Sinaloa, Mexico
.
Highlights
Indicated Resources:
10.3 Moz AgEq
*
- 3.4
Moz Ag
, 53 koz Au, 73 Mlbs Zn, and 48 Mlbs Pb
Inferred Resources:
21.0 Moz AgEq
*
-
8.6
Moz Ag
, 85 koz Au, 149 Mlbs Zn, and 116 Mlbs
Pb
The incorporation of extensive historical data and completion of the initial resource estimates at
the Plomosas Project ("Plomosas") incremental to the nearby San Marcial NI 43-101 mineral
resource estimate of 36.0 Moz AgEq
#
Indicated resources and 11.9 Moz AgEq
#
Inferred
resources (see
News Release dated
June 12, 2020
), represents a major milestone for GR
Silver Mining
Estimates include 80 new drill holes and 476 historic drill holes representing a total of
100,672
m
of drilling covering two areas, the former Plomosas Mine and the
San Juan
area (Figure 1)
The present resource included a sampling of historical drill holes completed by previous
companies that was frequently selective, resulting in a large amount of drill core unsampled; this
core is no longer available. Unsampled intervals within mineralized zones were assigned zero
values for the resource estimation, including in areas with evidence of precious and base metals
mineralization. Further drilling will address these blank spots to potentially continue resource
growth at the Plomosas Mine and
San Juan
areas
A
14,000m
drill program employing seven rigs is in progress on newly identified, high priority
Au–Ag targets outside the current resource areas (Figure 1)
GR Silver Mining President and CEO,
Marcio Fonseca
commented:
"The publication of the
initial resource estimates at the Plomosas Project is the result of a systematic collection of
geological information, data review and analysis in a 3D model. This has also allowed for multiple
discoveries of high-grade silver and gold mineralization outside of the main mineralized body and
has encouraged the
Company to continue drilling on multiple targets outside of the resource area.
These results, together with the existing NI 43-101 mineral resource estimate at the nearby San
Marcial Project, represent a major milestone for the Company, increasing GR Silver Mining's
combined AgEq Indicated resources by 29% and Inferred resources by 176% in the Rosario
Mining District. The completion of the resource estimation and ongoing drilling creates a
cornerstone for GR Silver Mining's goal to deliver further discoveries and resource growth in
Mexico
.
"I would like to take this opportunity to thank all staff, who have embraced the challenge to
complete two initial NI 43-101 resource estimates within a nine-month time frame during a
pandemic, which today form the foundation for Plomosas' future growth. GR Silver Mining's strict
protocols for COVID-19 mitigation have effectively reduced active cases amongst staff and
contractors to nil, allowing us to accelerate exploration of the Company's core, 778 square
kilometer Project."
Figure 1 – Resource Estimation Areas – Plomosas Mine and San Juan Areas
1
Figure 1 – Resource Estimation Areas – Plomosas Mine and San Juan Areas(1) (1) New Au-Ag
targets of the ongoing Drill Program are shown in black (CNW Group/GR Silver Mining Ltd.)
1
New Au-Ag targets of the ongoing Drill Program are shown in black
Non-Executive Chairman,
Eric Zaunscherb
stated:
"the compilation of data and initial mineral
resource estimates for the Plomosas Mine and
San Juan
areas establish baselines for growth for
these areas, much as the release of the initial San Marcial mineral resource estimate established
a baseline for growth for that area in
February 2019
. We are excited by the geological model that
has evolved from the bounty of historical data gleaned from the Company's district-scale
consolidation. In particular, the model provides the robust rationale underlying the current drill
program, designed to follow up high-grade precious metal intersections, as well as a cogent
strategy for enhancing these initial mineral resource estimates."
Geological Data
Data representing 556 core drill holes; 80 new drill holes and 476 historic drill holes - together with
geological reconnaissance, underground mapping, and detailed geological mapping on surface, have
proved valuable components to delineate an extensive precious metal-rich system.
Drill core from recent surface and underground resource drilling followed strict QAQC protocols and
is stored on site at the project core storage facilities. Historical drill holes feature historical
documentation and field evidence of drill hole collars to support full integration of both datasets.
Validation drilling was completed at the Plomosas Mine and
San Juan
areas, with the Company drill
testing some historical surface and underground drill sites in 2020 and 2021. These tests validated
geochemical assay reports of mineralized zones previously intersected by historic diamond core
drilling.
Sampling of historical drill core by previous companies was frequently selective with sampling only
performed on specific core intervals, leaving many unsampled intervals within mineralized zones.
Nearby underground geological investigations and channel sampling demonstrated that many of
these unsampled intervals feature precious and base metal mineralization. For the purposes of the
resource estimate, these unsampled intervals between mineralized zones have been conservatively
assigned zero values by GR Silver Mining, which likely results in underestimation of grade for
portions of the resource model. Further drilling will address this situation to potentially continue
resource growth at the Plomosas Mine and
San Juan
areas. The entire dataset has been recently
surveyed, including detailed laser surveying of all underground workings.
Geology
There are at least two distinct mineralizing events identified at the Plomosas Mine to date. The
principal structure at the Plomosas Mine is the Plomosas Breccia, a low-angle N-S trending fault
breccia ("Plomosas Fault"), which hosts the primary precious and base metal mineralized zone. This
structure has a general dip angle of 30° to 40° to the west with dilatational features and wide
mineralized sections that are between one and eight meters thick. Mineralization in the Plomosas
Breccia is principally by replacement of pre-existing fault breccia and in the original wall rocks.
Precious metal-rich epithermal veins are hosted by steep NW-SE, N-S and NE-SW trending faults
that crosscut the Plomosas Fault and commonly define high-grade zones by later enrichment at the
intersections with, or proximal to, the Plomosas Breccia (Figure 2). In parts, precious metal
mineralization is found in contact breccias of intrusive rhyolite and diorite dykes.
These late precious metal-rich mineralized zones are at a preliminary stage of exploration with only
limited data incorporated into the 3D model to date. Further drilling is warranted to better define its
full potential.
Figure 2 – 3D Representation of the Plomosas Mine Area
Figure 2 – 3D Representation of the Plomosas Mine Area (CNW Group/GR Silver Mining Ltd.)
At the
San Juan
area, two veins were modelled based on shallow surface-only core drilling, namely
the mineralized
San Juan
and
La Colorada
veins. The
San Juan
vein is hosted in a low-angle north-
south trending fault breccia ("San Juan Fault") generally dipping at an angle of 40° to 50° to the east.
The polymetallic silver-gold rich mineralization has a much narrower geometry than that observed at
the Plomosas Mine. Similar to the Plomosas Mine, there is evidence supporting the presence of
several precious metal-rich mineralized zones, which are at an early stage of modelling at
San Juan
(Figure 3). The
La Colorada
vein is hosted in a low-angle north-south trending fault ("La Colorada
Fault") parallel to the San Juan Fault. Preliminary wide spaced surface core drilling has defined a
predominantly gold-silver hydrothermal vein breccia.
Figure 3 – 3D Representation of the
San Juan Area
including the
San Juan
and
La Colorada
veins
Figure 3 – 3D Representation of the San Juan Area including the San Juan and La Colorada veins
(CNW Group/GR Silver Mining Ltd.)
The precious metal-rich zones recently identified in the geological models at both the Plomosas Mine
and the
San Juan
areas have emerged as the primary focus of the current exploration drilling
program, concentrating on targets and geological settings where there are indications of favorable
geology for additional discoveries.
Mineral Resource Estimates
The mineral resource estimates for the Plomosas Mine and
San Juan
areas were provided by Dr.
Gilles Arseneau
, P.Geo. of ARSENEAU Consulting Services Inc. (ACS) using Geovia Gems Version
6.8.4. The Plomosas Mine mineral resources were estimated by ordinary kriging into
5m
cube
blocks, and the
San Juan
mineral resources were estimated by the Inverse Distance Squared
method. Grades were capped prior to compositing to
1 m
. Block grades were estimated in three
successive passes for the Plomosas Mine and four passes for the
San Juan
area. The historical
Grupo Mexico drill holes were only used for passes two and three at the Plomosas Mine and for
passes three and four at the
San Juan
area. Blocks estimated with Grupo Mexico drill holes were all
classified as inferred mineral resources. Blocks estimated during Pass 1 with at least two drill holes
or Pass 2 at
San Juan
, with at least four drill holes, were classified as Indicated.
Mineral resources are reported using a dollar equivalent based on the following metal prices and
recoveries determined from recent metallurgical tests. The mineral resources are reported using pit
constrained ("Whittle Pit Assessment") and Underground stope optimizer ("MSO") with operational
cost assumptions reported in Table 1.
Table 1 – Summary Parameters Adopted for Resource Estimation and Mineral Resource
Reporting - Plomosas Mine and San Juan Areas
Plomosas Project
Metal Prices
Gold US$/oz
1,600
Silver US$/oz
20
Lead US$/lb
0.90
Zinc US$/lb
1.10
Area
Plomosas Mine
San Juan
Grade Capping
Gold g/t
20
10
Silver g/t
450
360
Lead %
13
13
Zinc %
11
8
Metallurgical Recoveries***
Gold
86 %
79 %
Silver
74 %
71 %
Lead
69 %
58 %
Zinc
75 %
47 %
Preliminary Cost Assumptions
Mineral Resource Reporting****
Open Pit ("OP")
36 US$/t
36 US$/t
Underground ("UG")
50 US$/t
50 US$/t
*** Based on preliminary metallurgical testwork completed in 2021 with samples from both areas investigating potential production of precious metal-rich concentrate
**** Preliminary cost assumptions adopted in the Whittle assessment and MSO are based on similar type deposits in Mexico where underground and open pit operations are in
progress for a throughput capacity of 1500 tpd
The reasonable prospect of economic extraction was defined by generating a Whittle optimized pit
shell based on the above metal prices and recoveries and assuming a total open pit mining cost and
processing cost of
US$36
/t. Underground resources were restricted to shapes defined by stope
optimizer software and assumed combined underground mining and processing costs of
US$50
/t.
The mineral resource estimates are based upon drilling completed by the Company between 2020
and 2021, and earlier drilling by previous operators. The resource table for the Plomosas Project is
detailed below.
Table 2 - Plomosas Project Mineral Resource Statement
Plomosas Mine Area Mineral Resource Statement ACS - August 23, 2021
Resource
Category
Type
Tonnage
MT
Au
g/t
Au
KOz
Ag
g/t
Ag
Moz
Pb
%
Pb
MLbs
Zn
%
Zn
MLbs
Ag Eq
Moz
AgEq*
g/t
Indicated
OP
0.3
0.21
2
74
0.6
1.0
5.9
0.9
5.0
1.0
115
Inferred
OP
1.2
0.07
3
75
2.9
0.9
24.3
0.8
20.0
3.9
102
Indicated
UG
1.7
0.84
46
27
1.4
0.9
33.5
1.4
52.9
7.5
137
Inferred
UG
3.4
0.50
55
40
4.3
0.9
68.5
1.1
83.0
12.6
116
Total
Indicated
2.0
0.76
48
33
2.1
0.9
39.4
1.3
57.9
8.5
134
Total
Inferred
4.6
0.39
58
49
7.2
0.9
92.8
1.0
103.0
16.5
112
San Juan Area Mineral Resource Statement ACS - August 23, 2021
Resource
Category
Type
Tonnage
MT
Au
g/t
Au
KOz
Ag
g/t
Ag
Moz
Pb
%
Pb
MLbs
Zn
%
Zn
MLbs
Ag Eq
Moz
AgEq*
g/t
Indicated
OP
0.1
0.19
0
115
0.3
0.3
0.5
0.6
1.1
0.3
111
Inferred
OP
0.2
0.37
3
92
0.7
0.6
3.0
0.7
3.4
0.8
111
Indicated
UG
0.4
0.35
4
87
1.1
1.0
8.2
1.7
13.8
1.6
132
Inferred
UG
1.0
0.77
24
22
0.7
0.9
19.9
2.0
42.2
3.6
116
Total
Indicated
0.5
0.32
5
92
1.3
0.9
8.7
1.5
14.9
1.9
128
Total
Inferred
1.2
0.70
27
36
1.4
0.9
22.9
1.7
45.6
4.5
115
Plomosas Project Total Resources Statement ACS - August 23, 2021
Resource
Category
Type
Tonnage
MT
Au
g/t
Au
KOz
Ag
g/t
Ag
MOz
Pb
%
Pb
MLbs
Zn
%
Zn
MLbs
Ag Eq
Moz
AgEq*
g/t
Indicated
OP
0.3
0.20
2
83
0.9
0.8
6.4
0.8
6.1
1.3
114
Inferred
OP
1.4
0.12
5
78
3.6
0.9
27.3
0.7
23.5
4.8
103
Indicated
UG
2.1
0.76
50
38
2.5
0.9
41.7
1.5
66.7
9.1
136
Inferred
UG
4.4
0.57
79
36
5.0
0.9
88.4
1.3
125.1
16.2
116
Total
Indicated
2.4
0.68
53
44
3.4
0.9
48.1
1.4
72.8
10.3
133
Total
Inferred
5.8
0.46
85
46
8.6
0.9
115.7
1.2
148.6
21.0
113
*
AgEq is based on parameters presented in Table 1
The following table illustrates the nearby San Marcial Project NI 43-101 Mineral Resource Estimates
estimated by
Marcelo Filipov
, P.Geo of WSP Canada Inc. and
Todd McCracken
, P.Geo of WSP
Canada Inc. Both Mr. Filipov and Mr. McCracken are Qualified Persons as defined by National
Instrument 43-101 (link to
San Marcial NI 43-101 Resource Report
).
Table 3 - San Marcial Area Mineral Resource Table
San Marcial Resources Statement - February 7, 2019
Resource
Type
Tonnage
Au
Au
Ag
Ag
Pb
Pb
Zn
Zn
Ag Eq
AgEq#
Category
MT
g/t
KOz
g/t
MOz
%
MLbs
%
MLbs
Moz
g/t
Indicated (OP+UG)
OP+UG
7.6
na
na
117
29.0
0.3
53.0
0.5
86.0
36.0
147
Inferred (OP+UG)
OP+UG
3.4
na
na
91
10.0
0.1
8.0
0.4
26.0
12.0
108
# AgEq is based on long term silver, zinc and lead prices of US$18.50 per ounce silver, US$1.10 per pound zinc and US$0.95 per pound lead. The following average metallurgical
recoveries are assumed as 85% silver, 85% zinc and 95% lead. A 30 gpt AgEq cut off for open pit and 80 gpt AgEq for underground resource classification completed by WSP
Canada Inc. on February 06, 2019. OP is amenable for potential open pit development, UG is amenable for potential underground development. "na" = not estimated
Quality Assurance / Quality Control
All assay data are verified by means of a rigorous QA/QC program which included the insertion of
certified reference materials, blanks and duplicates into sample batches that are sent to SGS de
México, S.A. de C.V. laboratory facilities in
Durango, Mexico
, for sample preparation and analysis.
The results of the QA/QC program are monitored by GR Silver Mining personnel and the Qualified
Person. For every sample with results above Ag >100 ppm (over limits), these samples are
submitted directly by SGS de México to SGS Canada Inc. at
Burnaby, BC
. The analytical methods
are 4-acid digestion and Inductively Coupled Plasma Optical Emission Spectrometry with Lead
Fusion Fire Assay, with Gravimetric Finish for silver above over limits. For gold assays, the analytical
methods are Lead Fusion and Atomic Absorption Spectrometry Lead Fusion Fire Assay, and
Gravimetric Finish for gold above 10 ppm (over limits).
The recent drill holes completed by First Majestic from 2016 to 2018, followed QA/QC protocols
reviewed and validated by GR Silver Mining, including insertion of blank and standard samples in all
sample lots sent to First Majestic's Laboratorio Central facilities in La Parilla, Durango, for sample
preparation and assaying. Additional validation and check assays were performed by an
independent laboratory at SGS de México, S.A. de C.V. facilities in
Durango, Mexico
. The analytical
methods applied for these recent holes for Ag and Au assays are comprised of Fire Assay with
Atomic Absorption finish for samples above Au >10 ppm and Ag >300 ppm and Gravimetric Finish.
Lead and zinc were analyzed using Inductively Coupled Plasma Optical Emission Spectrometry. GR
Silver Mining has not received information related to the Grupo Mexico QA/QC and assay protocols
and at this stage is considering the information historical for news release purposes.
Qualified Person
The mineral resource estimate was completed by independent consultant Dr
Gilles Arseneau
, P.
Geo. of ARSENEAU Consulting Services Inc., a registered professional, who is an independent
Qualified Person (QP) as defined by NI 43-101. Mineral resources are reported in accordance with
CIM (2014) Definition Standards for Mineral Resources and Mineral Reserves in accordance with NI
43-101. Dr. Arseneau is a P. Geo. and is qualified as a Mineral Resource estimator and has over 25
years of relevant industry experience.
The scientific and technical data contained in this News Release related to the Plomosas Project
was reviewed and/or prepared under the supervision of
Marcio Fonseca
, P. Geo. He has approved
the disclosure herein.
About GR Silver Mining Ltd
.
GR Silver Mining is a Canadian-based and
Mexico
-focused junior mineral exploration Company
engaged in cost-effective silver-gold resource expansion on its 100%-owned assets, which lie on the
eastern edge of the Rosario Mining District, in the southeast of Sinaloa State,
Mexico
. GR Silver
Mining controls 100% of two past producer precious metal underground and open pit mines within
two contiguous areas;
La Trinidad
and Plomosas (which include the integrated San Marcial Area).
Our Project represents a district scale 778 km
2
of advanced stage exploration property including
over 75 km strike length in three distinct, parallel structural corridors. These corridors have
preliminary evidence of deep-seated intrusives driving robust metal-bearing fluid flow through an
extensive network of conduits with evidence of high-grade and bulk silver-gold and polymetallic
mineralization in multiple events.
GR Silver Mining Ltd.
Mr.
Marcio Fonseca
, P. Geo.
President & CEO
Cautionary Statement Regarding Forward-Looking Information
This press release contains "forward-looking statements" within the meaning of applicable
Canadian securities legislation and information that are based on the beliefs of management and
reflect the Company's current expectations. When used in this press release, the words "estimate",
"project", "belief", "anticipate", "intend", "expect", "plan", "predict", "may" or "should" and the
negative of these words or such variations thereon or comparable terminology are intended to
identify forward-looking statements and information. Such statements and information reflect the
current view of the Company. Risks and uncertainties may cause actual results to differ materially
from those contemplated in those forward-looking statements and information. By their nature,
forward-looking statements involve known and unknown risks, uncertainties and other factors
which may cause our actual results, performance or achievements, or other future events, to be
materially different from any future results, performance or achievements expressed or implied by
such forward-looking statements.
Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is
defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy
or accuracy of this press release.
SOURCE
GR Silver Mining Ltd.
View original content to download multimedia:
http://www.newswire.ca/en/releases/archive/August2021/23/c9071.html
%SEDAR: 00040149E
For further information:
Brenda Dayton, VP Corporate Communications, Telephone:
+1.604.558.6248, Email: [email protected]
CO: GR Silver Mining Ltd.
CNW 18:33e 23-AUG-21