Overview
The Guanajuato Mine Complex (GMC) is Great Panther's largest operation in Mexico and includes production from the Guanajuato and San Ignacio underground mines. For the purposes of resource estimation, GMC also includes the El Horcon project as future production from El Horcon would be trucked to the GMC Cata processing plant.
GMC is located within the Guanajuato district – historically one of Mexico’s most prolific mining districts, with past production of over one billion ounces of silver and four million ounces of gold since the 16th century. The main Guanajuato mine, Cata processing plant and office facilities are situated in the outskirts of the capital city of Guanajuato, in Guanajuato State. These facilities have excellent infrastructure with access via city streets, and an international airport only 30 minutes away. The San Ignacio mine lies approximately eight kilometres to the west and is accessed by a 22-kilometre paved road. Ore from San Ignacio is trucked to the Cata processing plant.
GMC is an underground silver-gold operation that utilizes cut-and-fill mining methods. Numerous deposits are currently being mined with access provided by interconnected ramps. These same ramps connect to a primary ramp that is used for ore haulage to the surface. There also exists two operating shafts. Ore is processed into a high quality, precious metal-rich concentrate for transportation to smelters overseas. The Cata processing plant, located near the central Cata shaft, consists of the following three segments:
- three-stage crushing section, producing a (-¼ inch) fine ore mill feed;
- grinding section, consisting of three ball mills operated in parallel, and
- conventional flotation circuit with a total capacity of 1,000 tonnes per day.
Most of the supplies and skilled labour required for mining and processing at GMC are sourced from the cities of Guanajuato and Leon.
GMC is 100% owned by Great Panther.
The Guanajuato mine and the Cata processing plant were placed on care and maintenance in November 2021 while the Company awaits the permits from CONAGUA necessary to extend the tailings dam. Mining activity at the San Ignacio mine has also been suspended while Great Panther continues to proactively engage with CONAGUA in regards of the tailings dam permit and to explore other alternatives to maximize value from the GMC.
Operating Results
|
|
Q4 2021 |
Q4 2020 |
Change |
FY 2021 |
FY 2020 |
Change |
|
Ore processed (tonnes) |
27,844 |
39,539 |
-30% |
149,329 |
151,001 |
-1% |
|
Ag grade (g/t) |
127 |
117 |
9% |
117 |
125 |
-6% |
|
Au grade (g/t) |
1.70 |
1.46 |
16% |
1.60 |
1.66 |
-4% |
|
Ag recovery (%) |
87% |
86% |
1% |
87% |
86% |
2% |
|
Au recovery (%) |
86% |
84% |
2% |
87% |
84% |
3% |
|
Silver eq production (oz) (1) |
209,074 |
268,524 |
-22% |
1,051,336 |
1,131,025 |
-7% |
|
Silver production (oz) |
98,438 |
128,214 |
-23% |
485,315 |
520,903 |
-7% |
|
Gold production (oz) |
1,302 |
1,559 |
-16% |
6,659 |
6,779 |
-2% |
|
Gold eq production (oz) (2) |
2,460 |
2,984 |
-18% |
12,369 |
12,567 |
-2% |
- Silver equivalent ounces for 2021 were calculated using an 85:1 Ag:Au ratio, consistent with the Company's guidance for the year. Silver equivalent ounces for 2020 were calculated using a 90:1 Ag:Au ratio, consistent with the Company's guidance for the year.
- Gold equivalent ounces for 2021 were calculated using a 1:85 Au:Ag ratio, and ratios of 1:0.0005 and 1:0.0006 for the price/ounce of gold to price/pound of lead and zinc, respectively, consistent with the Company's guidance for the year. Gold equivalent ounces for 2020 were calculated using a 1:90 Au:Ag ratio, and ratios of 1:0.0006 and 1:0.0008 for the price/ounce of gold to price/pound of lead and zinc, respectively, consistent with the Company's guidance for the year.
Exploration
The Guanajuato property is situated along the core of the prolific Veta Madre silver-gold structure. The world-class, low-sulphidation epithermal deposits are somewhat unique as they locally demonstrate a vertical depth extent of greater than 600m (this is rare for epithermal deposits and implies a long-lived mineralizing system).
To a certain degree, deep extensions of mineralization can be found by following known deposits down plunge. Great Panther has been successful at discovering new mineralized zones through systematic drilling and a continually improving understanding of the structural controls. In this way, Great Panther has been successful in replacing what it mines each year. Due to the complex nature of the ore, some zones are mined as they are found, without the need (or time) for detailed drilling.
Resource Estimates
Total GMC Mineral Resource Estimates at July 31, 2021
|
Class |
Tonnes |
Ag (g/t) |
Ag(oz) |
Au (g/t) |
Au (oz) |
Ag Eq(g/t) |
Ag Eq (oz) |
Au Eq (g/t) |
Au Eq (oz) |
|
Measured |
368,944 |
196 |
2,329,550 |
2.36 |
27,948 |
397 |
4,708,345 |
4.67 |
55,392 |
|
Indicated |
150,550 |
194 |
940,377 |
2.16 |
10,438 |
378 |
1,829,410 |
4.45 |
21,522 |
|
M&I |
519,493 |
196 |
3,269,927 |
2.30 |
38,386 |
391 |
6,537,755 |
4.61 |
76,915 |
|
Inferred |
665,977 |
194 |
4,149,076 |
2.42 |
51,876 |
400 |
8,558,540 |
4.70 |
100,689 |
Notes:
- Cut-offs are based on the marginal operating costs per mining area being US$135.70/tonne for Cata, US$135.70/tonne for Santa Margarita, US$96.50/tonne for Los Pozos, US$124.90/tonne for Guanajuatito, US$148.50/tonne for Promontorio, US$113.10/tonne for Valenciana, and US$135.70/tonne for San Ignacio.
- Block model grades converted to USD NSR value using plant recoveries of 87.15% Ag, 86.70% Au, and net smelter terms negotiated for concentrates.
- Rock Density for Cata is 2.66t/m³, 2.65t/m³ Santa Margarita, Los Pozos 2.68t/m³, Guanajuato 2.69t/m³, Promontorio and Valenciana 2.67t/m³, and for San Ignacio is 2.64t/m³.
- Totals may not agree due to rounding.
- Grades in metric units.
- Contained silver and gold in troy ounces.
- Minimum true width 0.5m.
- Metal Prices US$20.00/oz silver, and US$1,650.00/oz gold.
- Effective date of July 31, 2021.
- AgEq oz were calculated using 85:1 Ag:Au ratio.
- Inferred Mineral Resources have a great amount of uncertainty as to their existence and as to whether they can be mined legally or economically. It cannot be assumed that all or part of the Inferred Mineral Resources will ever be upgraded to a higher category.
- Mineral Resources that are not Mineral Reserves have no demonstrated economic viability.
Guanajuato Mineral Resource Estimates at July 31, 2021
|
Class |
Tonnes |
Ag (g/t) |
Ag(oz) |
Au (g/t) |
Au (oz) |
AgEq (g/t) |
AgEq (oz) |
AuEq (g/t) |
AuEq (oz) |
|
Measured |
166,262 |
255 |
1,362,426 |
1.81 |
9,681 |
409 |
2,185,272 |
4.81 |
25,709 |
|
Indicated |
85,404 |
240 |
658,767 |
1.68 |
4,600 |
382 |
1,049,757 |
4.50 |
12,350 |
|
M&I |
251,666 |
250 |
2,021,193 |
1.76 |
14,280 |
400 |
3,235,029 |
4.70 |
38,059 |
|
Inferred |
220,760 |
225 |
1,597,357 |
1.95 |
13,873 |
391 |
2,776,596 |
4.60 |
32,666 |
Notes:
- Cut-offs are based on the marginal operating costs per mining area being US$135.70/tonne for Cata, US$135.70/tonne for Santa Margarita, US$96.50/tonne for Los Pozos, US$124.90/tonne for Guanajuatito, US$148.50/tonne for Promontorio, and US$113.10/tonne for Valenciana.
- Block model grades converted to US$ value using plant recoveries of 87.15% Ag, 86.70% Au, and net smelter terms negotiated for concentrates.
- Rock Density for Cata is 2.66t/m³, 2.65t/m³ Santa Margarita, Los Pozos 2.68t/m³, Guanajuato 2.69t/m³, Promontorio and Valenciana 2.67t/m³.
- Totals may not agree due to rounding.
- Grades in metric units.
- Contained silver and gold in troy ounces.
- Minimum true width 0.5m.
- Metal Prices US$20.00/oz silver, and US$1,650.00/oz gold.
- Effective date of July 31, 2021.
- AgEq oz were calculated using 85:1 Ag:Au ratio.
- Inferred Mineral Resources have a great amount of uncertainty as to their existence and as to whether they can be mined legally or economically. It cannot be assumed that all or part of the Inferred Mineral Resources will ever be upgraded to a higher category.
- Mineral Resources that are not Mineral Reserves have no demonstrated economic viability.
San Ignacio Mineral Resource Estimates at July 31, 2021
|
Class |
Tonnes |
Ag (g/t) |
Ag (oz) |
Au (g/t) |
Au (oz) |
AgEq (g/t) |
AgEq (oz) |
AuEq (g/t) |
AuEq (oz) |
|
Measured |
202,682 |
148 |
967,124 |
2.80 |
18,267 |
387 |
2,523,073 |
4.56 |
29,683 |
|
Indicated |
65,146 |
134 |
281,611 |
2.79 |
5,839 |
372 |
779,653 |
4.38 |
9,172 |
|
M&I |
267,828 |
145 |
1,248,734 |
2.80 |
24,106 |
384 |
3,302,726 |
4.51 |
38,856 |
|
Inferred |
445,217 |
178 |
2,551,719 |
2.65 |
38,002 |
404 |
5,781,944 |
4.75 |
68,023 |
Notes:
- Cut-offs are based on the marginal operating costs per mining area being US$127,40/tonne for San Ignacio.
- Block model grades converted to US$ value using plant recoveries of 87.15% Ag, 86.70% Au, and net smelter terms negotiated for concentrates.
- Rock Density for San Ignacio is 2.64t/m³,
- Totals may not agree due to rounding.
- Grades in metric units.
- Contained silver and gold in troy ounces.
- Minimum true width 0.5m.
- Metal Prices US$20.00/oz silver, and US$1,650.00/oz gold.
- Effective date of July 31, 2021.
- AgEq oz were calculated using 85:1 Ag:Au ratio.
- Inferred Mineral Resources have a great amount of uncertainty as to their existence and as to whether they can be mined legally or economically. It cannot be assumed that all or part of the Inferred Mineral Resources will ever be upgraded to a higher category.
- Mineral Resources that are not Mineral Reserves have no demonstrated economic viability.
Robert F. Brown , P. Eng., and Mohammad Nourpour, P. Geo., are the Qualified Persons for the GMC Mineral Resource Estimate under the meaning of National Instrument 43-101 – Standards of Disclosure for Mineral Projects. For additional information and disclosure related to the GMC Mineral Resource Estimate, please refer to the news release dated February 11, 2021.