Sierra Madre Increases M&I Silver-Equivalent Resources at La Guitarra by 373% to 27.2 million Ounces, Inferred Silver- Equivalent Resource Increased 204%to 20.2 million Ounces
VANCOUVER, BC / ACCESSWIRE / November 1, 2023 / Sierra Madre Gold and Silver Ltd. (TSXV:SM)(OTCQX:SMDRF) ("Sierra Madre" or the "Company") is pleased to announce its first project-wide Resource Estimate for the La Guitarra silver-gold mine and the Temascaltepec mining district in Estado de Mexico, Mexico. TechSer Mining Consultants Ltd. ("TechSer") of Vancouver B.C. prepared the Mineral Resource Estimate, David Thomas, P.Geo. and QP Geology and Cristian Garcia, P.Eng. and QP Mining. The following tabulates the La Guitarra estimated Mineral Resources.
Table 1: Summary La Guitarra 2023 Mineral Resource Estimate, David G. Thomas P. Geo (Effective Date: October 24, 2023)
Class
Tonnes
AgEq (g/t)
Ag
(g/t)
Au (g/t)
AgEq Ozs
Ag Ozs
Au Ozs
Indicated
3,842,000
220
146
0.96
27,207,000
18,073,000
118,000
Inferred
4,105,000
153
113
0.52
20,199,000
14,937,000
68,000
See notes following Table 3
Gregory K. Liller states, "I am extremely pleased with the results of the new mineral resource estimation. This study validates our belief that La Guitarra has a significantly overlooked resource base. Since April, our staff has been working on validating the project-wide database, incorporating historical data, auditing the previously mined areas, and refining the geologic interpretation of the vein and models. The next step to re-opening the Guitarra mine will be a Mine and Restart Plan due in the first quarter of 2024; consisting of a capital and operating cost study, the results of which will be used to evaluate the economic potential of the mine."
The following tabulates the Mineral Resource Estimates by Classification and Area;
Table2: Indicated Mineral Resource Estimate
Area
Tonnes
AgEq (g/t)
Ag
(g/t)
Au (g/t)
AgEq Ozs
Ag Ozs
Au Ozs
Nazareno
310,000
257
215
0.55
2,564,000
2,141,000
5,000
Coloso
432,000
346
221
1.61
4,806,000
3,071,000
22,000
Guitarra
1,649,000
220
123
1.25
11,664,000
6,544,000
66,000
Sub-Total
2,391,000
248
153
1.22
19,034,000
11,756,000
93,000
Los Angeles
690,000
177
109
0.87
3,919,000
2,419,000
19,000
Mina De Agua
761,000
174
159
0.19
4,255,000
3,899,000
5,000
Total Indicated
3,842,000
220
146
0.96
27,208,000
18,074,000
117,000
Table 3: Inferred Mineral Resource Estimate
Area
Tonnes
AgEq (g/t)
Ag (g/t)
Au (g/t)
AgEq Ozs
Ag Ozs
Au Ozs
Nazareno
754,000
252
229
0.29
6,096,000
5,554,000
7,000
Coloso
374,000
317
213
1.34
3,810,000
2,565,000
16,000
Guitarra
293,000
180
113
0.87
1,690,000
1,059,000
8,000
Sub-Total
1,421,000
254
201
0.68
11,596,000
9,178,000
31,000
Los Angeles
66,000
157
76
1.05
333,000
161,000
2,000
Mina De Agua
545,000
188
178
0.13
3,301,000
3,120,000
2,000
Subtotal UG Mine
2,032,000
233
191
0.55
15,230,000
12,459,000
35,000
Inferred Tailings
2,073,000
75
37
0.48
4,968,000
2,475,000
32,000
Total Inferred
4,105,000
153
113
0.52
20,198,000
14,934,000
67,000
(1) Notes for Mineral Resource Estimate:
Canadian Institute of Mining Metallurgy and Petroleum ("CIM") definition standards were followed for the resource estimate.
The 2023 resource models used nominal cutoff grades which are based on mining and milling costs of US$50 for cut and fill mining, US$38 per tonne for long-hole,
A net payable recovery of 70% (historical plant recovery plus an allowance for smelter deductions, refining costs, and concentrate transportation)
Silver price of US$22 and a gold price of $1700 and a Gold Silver Ration of 77.27:1.
Assays were capped at 825 g/t for silver and 6.55 g/t for gold
Variable cut-off by deposit
Nazareno and Coloso - Block Model 135 AgEq cut-off grade (COG) and a 1 m Minimum True Thickness
Guitarra - Polygonals Estimates 135 g/t AgEq COG and a 1 m Minimum Horizontal Width
Los Angeles - Block Model Long Hole Mining 90 g/t AgEq COG
Mina De Agua - East District Polygonal Estimate 135 g/t AgEq COG or 90 g/t AgEq COG and > 2 m Horizontal Width
The tailings used a 30 g/t AgEq COG.
Mineral Resources that are not mineral reserves do not have economic viability. Numbers may not add due to rounding.
Numbers may not add due to rounding.
The estimate of mineral resources may be materially affected by: metal prices and exchange rate assumptions; changes in local interpretations of mineralization geometry and continuity; changes to grade capping, density and domain assignments; changes to geotechnical, mining and metallurgical recovery assumptions; ability to maintain environmental and other regulatory permits and ability to maintain the social license to operate
The 2023 resource estimate is prepared by David Thomas P.Geo. and Q.P. and Cristian Garcia P.Eng. and QP, of TechSer in accordance with National Instrument 43-101 Standards of Disclosure for Mineral Projects. David Thomas and Cristian Garcia are independent qualified person ("QP's") as defined by National Instrument 43-101. A full technical report, which is being prepared in accordance with National Instrument 43-101 Standards of Disclosure for Mineral Projects, will be filed and available under the Company's SEDAR profile at www.sedar.com within 45 days of this news release.
Coloso and Nazareno Development Details
The Coloso mine supplied most of La Guitarra's production from 2015 to 2018 before being placed on care and maintenance. The Coloso and Narareno block models utilized wireframe models developed by First Majestic Silver which have been validated. The Coloso veins average width is 1.5 meters and the Nazareno veins have an average width of 4.3 meters. The Coloso mine has over 12 kilometres ("km") of existing and accessible ramps, haulage ways, cross cuts, ventilation shafts, and development drives. The Nazareno mineralization is accessed from the Coloso workings by a one km meter haulage way and was under development when the mine was closed.
Figure 1: Nazareno and Coloso Development Section
Guitarra Mine Details
The Guitarra Indicated Resources are contained in seven veins with a weighted average width (width x tonnes) for the Indicated Resources of 3.4 meters. The Guitarra mine has approximately 40 km of haulage ways, ramps, crosscuts, raises, and development drives. It is accessed from the surface at five primary levels along with several other hillside adits. A decline ramp accesses the San Rafael 1 and 2 areas and has two ventilation shafts.
Figure 2: Guitarra Mine Section
Sierra Madre management recognized that portions of the Guitarra veins and Santa Ana in the East District might be amenable to long-hole mining based on their previous mining experience at the Property and historic mining methods. The Los Angeles area in the Guitarra mine was found to have vein and stockwork mineralization in a configuration that could be amenable to long-hole mining methods. The Los Angeles mineralization is accessible on three haulage way levels, several ramps, and multiple development drives. Existing ore passes on the La Cruz, Los Angeles, San Francisco, and Garambullo levels connect to the San Rafael haulage way, the primary haulage way to the Guitarra flotation plant.
Figure 3: Los Angeles Section
Tlacotal Project
The Santa Ana vein (also known as Mina de Agua shown in Table 2 and Table 3) in the East District has an average width of 7.1 meters. First Majestic completed an approved Environmental Impact Statement (MIA) to develop Santa Ana. The operating area is called La Tlacotal, and the Company has a long-term land use agreement on the surface.
Mr. Gregory Smith, P. Geo, Director of Sierra Madre, is a Qualified Person as defined by NI 43-101, and has reviewed and approved the technical data and information contained in this news release. Mr. Smith has verified the technical and scientific data disclosed herein.
About Sierra Madre
Sierra Madre Gold & Silver (TSX.V:SM)(OTCQX:SMDRF) is a precious metals development and exploration company, focused on evaluating the potential of restarting the La Guitarra Mine in the Temascaltepec mining district, Mexico, and the exploration and development of its Tepic and La Tigra properties in Nayarit, Mexico. The La Guitarra Mine is a permitted, past-producing underground mine which includes a 500 t/d processing facility that operated until mid-2018.
The +2,600 ha Tepic Project hosts low-sulphidation epithermal gold and silver mineralization with an existing historic resource. La Tigra, located 148 km north of Tepic, has been mined historically; Sierra Madre′s maiden 2022 drill program at the site intercepted shallow mineralization.
Sierra Madre′s management has played key roles for managing exploration and development of more than 22Moz gold and 600Moz silver in combined reserves and resources. Sierra Madre′s team of professionals has collectively raised over $1B for mining companies.
On behalf of the board of directors of Sierra Madre Gold and Silver Ltd.,
"Alexander Langer"
Alexander Langer President, Chief Executive Officer and Director +1 (604) 765-1604
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