Rosario
Overview
The state of Sinaloa is well known for its mining industry and best known for its gold, silver, lead, copper and zinc deposits. In particular, the Rosario mining district is known historically as a significant area for silver, gold, lead and zinc production.
The Rosario mining concession totals 16,279 hectares in south east Sinaloa, Mexico. This land package is located approximately 94 km southeast of Mazatlan and nearby the town of Rosario. The mining concession represents a high priority mining district and consolidates three past producing mines: Plomosas, San Juan and San Marcial. Extensive infrastructure is in place at Rosario, including a fully functional mining camp facility at the Plomosas mine. Facilities and infrastructure at Rosario include a 20 year surface rights agreement in good standing, a 30 year water use permit, tailings dam, 60 km - 33 KV power line, 120 man camp, infirmary, offices, shops and warehouses, and assay lab.
Historic production on the Rosario Project by Grupo Mexico, the previous operator, averaged 600 tonnes per day ("tpd") from 1986 to 2000. During this production period a total of 2.5 million tonnes of ore were extracted that averaged 190.5 g/t Ag, 0.92 g/t Au, 2.02% Zn and 2.38% Pb. Operations were ceased in 2001 due to low metal prices and a regional labour dispute.
Extensive underground development at the Plomosas and San Juan mines allow rubber tire access to mineralized zones. This existing development will allow Silvermex to accelerate development at significant cost savings. At Plomosas, Grupo Mexico invested approximately $11 million in property payments, exploration, upgrades and renovations to the mine and mill site, including upgrading of electrical substations and wiring, camp and accommodations, mine dewatering and detailed engineering of an 800 tpd mill designed to be installed on the existing foundations and structures. The land directly surrounding the Rosario mill site (330 ha) is owned in fee simple.
The Company is utilizing the mining camp infrastructure while it continues to develop the projects toward a commercial production decision. Future plans at Rosario include the preparation of an NI 43-101 resource estimate and the continued exploration at depth and along strike of the existing known structure. The company will also collect material for advanced metallurgical testing and, if justified, develop a comprehensive mine plan for the potential extraction of the resource.
There are two key areas of interest within the Rosario mining camp: Plomosas and San Juan. These were acquired from Aurcana Corporation ("Aurcana") in December 2009. San Marcial is not an area of focus for Silvermex at this time.
The state of Sinaloa is well known for its mining industry and best known for its gold, silver, lead, copper and zinc deposits. In particular, the Rosario mining district is known historically as a significant area for silver, gold, lead and zinc production.
The Rosario mining concession totals 16,279 hectares in south east Sinaloa, Mexico. This land package is located approximately 94 km southeast of Mazatlan and nearby the town of Rosario. The mining concession represents a high priority mining district and consolidates three past producing mines: Plomosas, San Juan and San Marcial. Extensive infrastructure is in place at Rosario, including a fully functional mining camp facility at the Plomosas mine. Facilities and infrastructure at Rosario include a 20 year surface rights agreement in good standing, a 30 year water use permit, tailings dam, 60 km - 33 KV power line, 120 man camp, infirmary, offices, shops and warehouses, and assay lab.
Historic production on the Rosario Project by Grupo Mexico, the previous operator, averaged 600 tonnes per day ("tpd") from 1986 to 2000. During this production period a total of 2.5 million tonnes of ore were extracted that averaged 190.5 g/t Ag, 0.92 g/t Au, 2.02% Zn and 2.38% Pb. Operations were ceased in 2001 due to low metal prices and a regional labour dispute.
Extensive underground development at the Plomosas and San Juan mines allow rubber tire access to mineralized zones. This existing development will allow Silvermex to accelerate development at significant cost savings. At Plomosas, Grupo Mexico invested approximately $11 million in property payments, exploration, upgrades and renovations to the mine and mill site, including upgrading of electrical substations and wiring, camp and accommodations, mine dewatering and detailed engineering of an 800 tpd mill designed to be installed on the existing foundations and structures. The land directly surrounding the Rosario mill site (330 ha) is owned in fee simple.
The Company is utilizing the mining camp infrastructure while it continues to develop the projects toward a commercial production decision. Future plans at Rosario include the preparation of an NI 43-101 resource estimate and the continued exploration at depth and along strike of the existing known structure. The company will also collect material for advanced metallurgical testing and, if justified, develop a comprehensive mine plan for the potential extraction of the resource.
There are two key areas of interest within the Rosario mining camp: Plomosas and San Juan. These were acquired from Aurcana Corporation ("Aurcana") in December 2009. San Marcial is not an area of focus for Silvermex at this time.
Plomosas - La Cruz
A 2001 report by Grupo Mexico states that the Plomosas Mine has existing historic reserves and resources of 638,756 tonnes grading 136 g/t Ag, 3.21 % Zn, 2.23 % Pb, and 1.05 g/t Au.* The Mine has extensive development and has been partially refurbished by the previous operator in preparation for an 800 tpd operation. The mine has been dewatered and has undergone partial rehabilitation. The historic reserves are located in a number of mineral zones, which include the Veta Plomosas, Plomositas, Lead-Zinc Stock Work and Silver Stock Work.
*The reader should be cautioned the historic reserves and resources at Plomosas do not conform to National Instrument 43-101 for reporting purposes; as such the Company is not treating these historic estimates as current reserves or resources. These estimates should not be relied upon until they have been verified by further due diligence and by the Company's "Qualified Person".
Extensive data collection, underground mapping, control surveys, resource modeling and preliminary exploration programs have been completed by the prior operator. An extensive underground channel sampling program has been completed at Plomosas, which yielded positive results with numerous high grade intersections of gold, silver, lead and zinc. Silvermex will focus on the potential that remains within these zones and intends to expand the resource from areas remaining between old mine levels along strike and below the lowest level exploited. The stock work zones have potential for tonnage expansion along the strike and dip of the Plomosas fault structure.
A 2001 report by Grupo Mexico states that the Plomosas Mine has existing historic reserves and resources of 638,756 tonnes grading 136 g/t Ag, 3.21 % Zn, 2.23 % Pb, and 1.05 g/t Au.* The Mine has extensive development and has been partially refurbished by the previous operator in preparation for an 800 tpd operation. The mine has been dewatered and has undergone partial rehabilitation. The historic reserves are located in a number of mineral zones, which include the Veta Plomosas, Plomositas, Lead-Zinc Stock Work and Silver Stock Work.
*The reader should be cautioned the historic reserves and resources at Plomosas do not conform to National Instrument 43-101 for reporting purposes; as such the Company is not treating these historic estimates as current reserves or resources. These estimates should not be relied upon until they have been verified by further due diligence and by the Company's "Qualified Person".
Extensive data collection, underground mapping, control surveys, resource modeling and preliminary exploration programs have been completed by the prior operator. An extensive underground channel sampling program has been completed at Plomosas, which yielded positive results with numerous high grade intersections of gold, silver, lead and zinc. Silvermex will focus on the potential that remains within these zones and intends to expand the resource from areas remaining between old mine levels along strike and below the lowest level exploited. The stock work zones have potential for tonnage expansion along the strike and dip of the Plomosas fault structure.
San Juan
The San Juan Mine is strategically located 3 km west of the Rosario mine site, along the road between the San Marcial deposit and the Plomosas mine and mill site. Grupo Mexico reported historic reserves and resources of 256,756 tonnes grading 329.3 g/t Ag, 3.73% Zn, 1.69% Pb, and 0.19 g/t Au*.
* The reader should be cautioned the historic reserves and resources Plomosas do not conform to National Instrument 43-101 for reporting purposes; as such the Company is not treating these historic estimates as current reserves or resources. The historical reserves do not have demonstrated current economic viability and are being treated as historical resources. These estimates should not be relied upon until they have been verified by further due diligence and by the Company's "Qualified Person".
The San Juan development consist of a main adit approximately 5 m in width, 5 m in height and 250 m long, a crosscut extending easterly for 150 m, plus a ramp with a further 150 m development. The mineralized structure averages 3 m in width and has been traced down dip for approximately 150-200 m. A decline has been driven into the San Juan zone and has been tested over a vertical distance of 40 m with the zone still open to depth.
Extensive data collection, underground mapping, control surveys and exploration programs have been completed at San Juan by previous operators.
San Marcial Technical Report
The San Juan Mine is strategically located 3 km west of the Rosario mine site, along the road between the San Marcial deposit and the Plomosas mine and mill site. Grupo Mexico reported historic reserves and resources of 256,756 tonnes grading 329.3 g/t Ag, 3.73% Zn, 1.69% Pb, and 0.19 g/t Au*.
* The reader should be cautioned the historic reserves and resources Plomosas do not conform to National Instrument 43-101 for reporting purposes; as such the Company is not treating these historic estimates as current reserves or resources. The historical reserves do not have demonstrated current economic viability and are being treated as historical resources. These estimates should not be relied upon until they have been verified by further due diligence and by the Company's "Qualified Person".
The San Juan development consist of a main adit approximately 5 m in width, 5 m in height and 250 m long, a crosscut extending easterly for 150 m, plus a ramp with a further 150 m development. The mineralized structure averages 3 m in width and has been traced down dip for approximately 150-200 m. A decline has been driven into the San Juan zone and has been tested over a vertical distance of 40 m with the zone still open to depth.
Extensive data collection, underground mapping, control surveys and exploration programs have been completed at San Juan by previous operators.
San Marcial
Overview
The San Marcial project consists of two mineral concessions covering a total area of 1,250 ha. The property is held through Silvermex's wholly owned Mexican subsidiary Minera Terra Plata S.A. de C.V. ("Terra Plata") and is located directly adjacent to Silvermex's Plomosas and San Juan properties.
San Marcial is under option from Silver Standard Resources Inc. ("Silver Standard").
Location
Silvermex's San Marcial silver project is located in the western Mexican state of Sinaloa, which is well known for its mining industry and best known for its gold, silver, lead, copper and zinc deposits. Specifically, the project is located within the south-eastern corner of Sinaloa, approximately 12.5 km south of the town of La Rastra within the La Rastra mining district and along the western edge of the Sierra Madre Occidental geological province. This linear belt of volcanic rocks, approximately 1,500 km long by 250 km wide, is known to host many important gold and silver producing mines and prospects. The province is divided into two main Tertiary volcanic units referred to as the Upper and Lower Volcanic groups, both of which are separated unconformably by a period of erosion and associated with local felsic intrusive activity. The contact between the two volcanic groups is highly prospective for precious metal mineralization.
History
While this district is known historically as a significant area for silver, gold, lead and zinc production as early as the 1600's, little is known about the exact discovery of San Marcial itself. However, during the 1780's and well into the early 1900's there are several local references from the library in El Rosario which indicate that the La Rastra to San Marcial corridor was an active silver-gold camp with over 20 known prospects and mines within a 15 km radius. Specifically these would include prospects such as Plomosas, El Saltito, Papayal and San Marcial. Prior to 2008 the most recent work on the San Marcial property was conducted by Gold-Ore Resources Ltd. (Gold-Ore) and Silver Standard between 2000 and 2002. This work included regional exploration, trenching and a 22 hole drill program totalling 3,128.47 m.
Geology
The San Marcial project area is situated along the western edge of the Sierra Madre Occidental geological province. This linear belt of volcanic rocks, approximately 1,500 km long by 250 km wide, is known to host many important gold and silver producing mines and prospects. The province is divided into two main Tertiary volcanic units referred to as the Upper and Lower Volcanic groups, both of which are separated unconformably by a period of erosion and associated with local felsic intrusive activity. The Lower Volcanic group is characterized by basal conglomerates, ignimbrites, rhyolites and felsic tuffs. The contact between the two volcanic groups (Lower and Upper) is highly prospective for precious metal mineralization, as a majority of the other known gold and silver mines and prospects in the belt occur close to, if not just below, the contact interval.
Unconformably underlying the Upper Volcanic group is the Lower Volcanic group of andesites and dacites which occur at lower elevations in the southwest and generally trend 015° and dip 45° to 68° easterly. The known silver prospects on the San Marcial property are hosted along what appears to be a narrow set of northwest trending fault structures with a 60° northeast dip which is in close proximity to the prospective unconformity. Along the trend and within the local area are prominent outcrops of highly weathered hydrothermal breccia and relatively fresh dacite porphyry intrusives. The volcanics vary from andesitic to dacitic ash tuffs, banded rhyolite flows interbedded with lapilli tuffs grading to agglomerate and andesitic conglomerate/agglomerate.
Faulting is common within the San Marcial area and is an important structural feature relating to the silver mineralization. There are at least four orientations of structural breaks or features interpreted from satellite imagery, trending primarily northwest, with fewer trending east, west, north and northeast. Movement along the northwest feature is normal but the displacement is unknown. The intersections of the east-west with northwest features are considered the most prospective areas for mineralization at San Marcial.
Exploration
Based on the exploration completed by the previous operators and a re-interpretation of the previous drilling as well as an increased understanding of the geology, mineralization and structural controls through Silvermex's 2008 mapping and sampling program, a drill program was conducted. The drilling program focused on confirming the mineral grades published by the previous operators with the objective of upgrading the inferred resource and exploring the extension along strike and down dip of the mineralized structure. Silvermex's 2008 exploration program was successful in confirming the historical exploration results and further defining the known mineralization located on the San Marcial property.
Resources and Reserves
The resource estimate by Silvermex and audited by Micon is compliant with the current CIM standards and definitions required by NI 43-101 and is, therefore, reportable as a mineral resource by Silvermex. However, the reader should be cautioned that mineral resources that are not mineral reserves do not have demonstrated economic viability. There are currently no mineral reserves on the San Marcial property.
Preliminary metallurgical testing on the San Marcial project returned encouraging results. Five oxide and sulphide samples from holes SM-2, SM-4 and SM-5 were sent to ALS Chemex in Reno, NV for column leach tests. Recoveries from all columns exceeded 80% over a 72 hour leach period. Additional metallurgical test work were completed on four samples composed of drill core rejects submitted to Process Research Associates Ltd. in Richmond, B.C. Recoveries from flotation and Cyanidation ranged from 90 to 97.9%.
Overview
The San Marcial project consists of two mineral concessions covering a total area of 1,250 ha. The property is held through Silvermex's wholly owned Mexican subsidiary Minera Terra Plata S.A. de C.V. ("Terra Plata") and is located directly adjacent to Silvermex's Plomosas and San Juan properties.
San Marcial is under option from Silver Standard Resources Inc. ("Silver Standard").
Location
Silvermex's San Marcial silver project is located in the western Mexican state of Sinaloa, which is well known for its mining industry and best known for its gold, silver, lead, copper and zinc deposits. Specifically, the project is located within the south-eastern corner of Sinaloa, approximately 12.5 km south of the town of La Rastra within the La Rastra mining district and along the western edge of the Sierra Madre Occidental geological province. This linear belt of volcanic rocks, approximately 1,500 km long by 250 km wide, is known to host many important gold and silver producing mines and prospects. The province is divided into two main Tertiary volcanic units referred to as the Upper and Lower Volcanic groups, both of which are separated unconformably by a period of erosion and associated with local felsic intrusive activity. The contact between the two volcanic groups is highly prospective for precious metal mineralization.
History
While this district is known historically as a significant area for silver, gold, lead and zinc production as early as the 1600's, little is known about the exact discovery of San Marcial itself. However, during the 1780's and well into the early 1900's there are several local references from the library in El Rosario which indicate that the La Rastra to San Marcial corridor was an active silver-gold camp with over 20 known prospects and mines within a 15 km radius. Specifically these would include prospects such as Plomosas, El Saltito, Papayal and San Marcial. Prior to 2008 the most recent work on the San Marcial property was conducted by Gold-Ore Resources Ltd. (Gold-Ore) and Silver Standard between 2000 and 2002. This work included regional exploration, trenching and a 22 hole drill program totalling 3,128.47 m.
Geology
The San Marcial project area is situated along the western edge of the Sierra Madre Occidental geological province. This linear belt of volcanic rocks, approximately 1,500 km long by 250 km wide, is known to host many important gold and silver producing mines and prospects. The province is divided into two main Tertiary volcanic units referred to as the Upper and Lower Volcanic groups, both of which are separated unconformably by a period of erosion and associated with local felsic intrusive activity. The Lower Volcanic group is characterized by basal conglomerates, ignimbrites, rhyolites and felsic tuffs. The contact between the two volcanic groups (Lower and Upper) is highly prospective for precious metal mineralization, as a majority of the other known gold and silver mines and prospects in the belt occur close to, if not just below, the contact interval.
Unconformably underlying the Upper Volcanic group is the Lower Volcanic group of andesites and dacites which occur at lower elevations in the southwest and generally trend 015° and dip 45° to 68° easterly. The known silver prospects on the San Marcial property are hosted along what appears to be a narrow set of northwest trending fault structures with a 60° northeast dip which is in close proximity to the prospective unconformity. Along the trend and within the local area are prominent outcrops of highly weathered hydrothermal breccia and relatively fresh dacite porphyry intrusives. The volcanics vary from andesitic to dacitic ash tuffs, banded rhyolite flows interbedded with lapilli tuffs grading to agglomerate and andesitic conglomerate/agglomerate.
Faulting is common within the San Marcial area and is an important structural feature relating to the silver mineralization. There are at least four orientations of structural breaks or features interpreted from satellite imagery, trending primarily northwest, with fewer trending east, west, north and northeast. Movement along the northwest feature is normal but the displacement is unknown. The intersections of the east-west with northwest features are considered the most prospective areas for mineralization at San Marcial.
Exploration
Based on the exploration completed by the previous operators and a re-interpretation of the previous drilling as well as an increased understanding of the geology, mineralization and structural controls through Silvermex's 2008 mapping and sampling program, a drill program was conducted. The drilling program focused on confirming the mineral grades published by the previous operators with the objective of upgrading the inferred resource and exploring the extension along strike and down dip of the mineralized structure. Silvermex's 2008 exploration program was successful in confirming the historical exploration results and further defining the known mineralization located on the San Marcial property.
Resources and Reserves
Category |
Tonnes |
Ag g/t |
Pb% |
Zn% |
Ag ozs |
Pb lbs |
Zn lbs |
|---|---|---|---|---|---|---|---|
Indicated |
3,756,000 |
149.20 |
0.36 |
0.67 |
18,021,000 |
29,932,000 |
55,328,000 |
Inferred |
3,075,000 |
44.21 |
0.29 |
0.51 |
4,371,000 |
19,526,000 |
34,691,000 |
The resource estimate by Silvermex and audited by Micon is compliant with the current CIM standards and definitions required by NI 43-101 and is, therefore, reportable as a mineral resource by Silvermex. However, the reader should be cautioned that mineral resources that are not mineral reserves do not have demonstrated economic viability. There are currently no mineral reserves on the San Marcial property.
Preliminary metallurgical testing on the San Marcial project returned encouraging results. Five oxide and sulphide samples from holes SM-2, SM-4 and SM-5 were sent to ALS Chemex in Reno, NV for column leach tests. Recoveries from all columns exceeded 80% over a 72 hour leach period. Additional metallurgical test work were completed on four samples composed of drill core rejects submitted to Process Research Associates Ltd. in Richmond, B.C. Recoveries from flotation and Cyanidation ranged from 90 to 97.9%.
San Marcial Technical Report