El Pinguico Project, Mexico
The Pinguico Project is located 7 kilometres southeast of Guanajuato city, in the State of Guanajuato, Mexico. The property consists of two mining concessions totalling 71 hectares.
Upcoming drill program
Underground drilling is set to commence in mid-November, primarily from the Don Ricardo target area. This drilling will use drill stations located at the end of cross-cuts within the mine, and will consist of approximately 2,100m of drilling in 12 holes. Surface drilling will commence in January, consisting of approximately 4,000m of drilling in 13 holes, and will include 3 holes to test for the extension of the regional Veta Madre fault structure.
Vangold Mining’s El Pinguico mine near Guanajuato Mexico was in production from the late 1880’s until 1913. In its day it was a very hi-grade producer of silver and gold.
Today, our historic mine is in close proximity to several active, modern mining operations including Endeavour Silver’s El Cubo and Bolanitos mine and mill complexes; Fresnillo PLC’s Las Torres mine and mill operation, and Great Panther Mining’s Guanajuato mine complex which includes the San Ignacio mine. All of these operations lie between 2 and 30km from Vangold’s principal project.
The property is approximately 2200 meters above sea level, and the terrain consists of gentle slopes with some abrupt changes in relief. Easy road access can be gained from Guanajuato.
The mining history of Guanajuato dates back to the sixteenth century, when the Spanish began mineral exploration in the region in 1520. Between 1548 and 1554 silver was discovered in the area of the San Bernabé and Rayas. This discovery led to the settling of people in the area and the city of Guanajuato as a population center. Guanajuato was one of the premier mining districts of Nueva España (New Spain) at this time.
01REGIONAL MINING HISTORY OF GUANAJUATO
1500 - 1700S
The mining history of Guanajuato dates back to the sixteenth century when the Spanish began mineral exploration in the region in 1520. Between 1548 and 1554 significant silver was discovered in the area of the San Bernabé mine, west of present day Guanajuato. This discovery led to the people settling in the area and the city of Guanajuato as a population centre was born. Guanajuato was one of the premier mining districts in New Spain at that time.
In 1548 the first silver vein, San Bernabé, was discovered by a local mule driver. At that time the silver ore was hand mined and sorted, then transported by mule to Zacatecas where it could be milled.
In 1558 the first mine shafts were sunk at the Rayas and Mellado mines, which led to the discovery of the now famous Veta Madre (or “Mother Vein”) of Guanajuato. These discoveries triggered an exploration rush that led to the identification of the Valenciana, Tepeyac, Mellado, Cata and Sirena silver mines. Today this vein can be seen running along the hills of Guanajuato for 30km, generally from northwest to southeast, and is marked by mines and shafts along most of its length.
During the period of 1760 to 1810, the Guanajuato mines in total accounted for 30% of Mexican silver production and 20% of the entire world’s output of silver. In fact, in 1771 very large amounts of silver sulphides, mixed with ruby silver and native silver were discovered at Valenciana and the Valenciana Mine was estimated to be producing one-third of the world’s silver.
02HISTORY OF THE EL PINGUICO SILVER & GOLD MINE
The El Pinguico project comprises two historic mines - the El Carmen and the El Pinguico, which are adjacent to one another, and which were eventually mined as one deposit after the merger of two companies. Early work is thought to have commenced around 1890, and the first rich deposits on the Pinguico property began to be exploited around 1904, just one year after ownership of El Pinguico was transferred from The Guanajuato Development Company to The Pinguico Mining and Milling Company. In total, the mine was in production from the late 1800’s to 1913 and produced over 200,000 ounces of gold equivalent (EMBSA, Proyecto El Pingüico, 2014). After several years of successful operation, the mines were closed due to local violence associated with the Mexican revolution.
The following paragraphs were taken from Mr. G. W. McElheney report, October 1945.
“In the year of 1903 the writer obtained a 25% interest in the Pinguico mine and shortly thereafter another 25%. His associates were two prominent Mexicans, a Mr. José M. Mena, the federal Tax collector of the State, and Mr. Amado Delgado, “the jefe político” of the city and district of Guanajuato (an official who at the time was practically a mayor, judge and jury combined). When acquired the property contained none a vestige of ore or even ore indications on the surface, but nevertheless development work, by hand, was once started. A shaft was sunk to a depth of 100’ at which point cross-cut were run in all directions, with no results. This was repeated at depth of 200’ and again 300’, all with no results and the finding of not a trace of ore. Then the shaft was carried on down to the 350’ depth where a short cross-cut encountered a narrow vein of rich ore which afterwards proved to have been the apex of the values in a true fissure – a fault replacement in Rhyolite, mineralized by ascending solutions with replacement features highly developed. The rhyolite had been covered to a vertical depth of 350’ below surface by non-ore bearing andesite tuff and breccias. This narrow vein rapidly widened as depth on it was attained until it reached a width varying from 10’ to 33’ all highly mineralized from wall to wall and running in values an average of $50.00 per ton for entire width of the vein and frequently running better than $100.00 per ton for great widths. After the pay ore was found, in the remarkably short space of four months’ time the development work pat in sight ore of a value of $2,101,906.00 it became the most talked- of mine in Mexico; its record is still ranked as one of the greatest bonanzas of modern mining in Mexico, and its gross production, as taken from official records, in the next succeeding six years was the sum of $5,233,832.71 and had gold been at its present value of $35.00 per ounce instead of $20.67 -the value Pinguico operating- the production would have exceeded one million dollars per year. Shortly after the finding of pay ore the writer bought out all of his associates, organized the Pinguico Mines Company and transferred the property to it; aggressive development was conducted; a modern cyanidation mill of 200 tons daily capacity was built, and the property quickly proved to be a real bonanza.” (G. W. McElheney, October 1945).
Later, in 1932 an engineer named Luis Frausto carried out feasibility studies at the two mines - El Carmen and El Pinguico - and according to his calculations, 75,000 metric tonnes of potentially economic mineral with estimated grades of 300 to 400 g/t Ag and 4 to 5 g/t of Au exist at the mine. (Of course, these figures are historic in nature, have not been verified and should not be relied upon. Additional work is required to verify the tonnage and grade of any minerals at these historic mines. A “qualified person” as defined under NI 43-101 has not done sufficient work to classify this historical estimate as current mineral resources or mineral reserves and Vangold is not treating the historical estimate as current mineral resources or mineral reserves).
03UNDERGROUND STOCKPILE OF MINERALIZED MATERIAL
Inside the El Pinguico mine, there is a large stockpile of broken mineralized material, which has existed since the mine closed in 1913. The Mexican Geological Survey (CRM in 1959 and SGM in 2012) have completed historical estimates of the stockpile's size and grade. Vangold undertook a trench sampling program of the underground stockpile in 2017 with a view to validating these historical estimates using NI 43-101 sampling standards.
(Vangold cautions that the following historical estimates were made prior to the adoption of NI 43-101, do not comply with the categories of classification set out in NI 43-101 or CIM guidelines, have not been verified and should not be relied upon. Additional work is required to verify the tonnage and grade of any minerals in the underground stockpile. A “qualified person” as defined under NI 43-101 has not done sufficient work to classify these historical estimates as current mineral resources or mineral reserves and Vangold is not treating such historical estimates as current mineral resources or mineral reserves. They are shown to give the reader a full account of historic work on the property.)
In 1959 the Mexican Geological Survey or “Consejo de Recursos Minerales” (CRM), completed a topographic survey of the underground stockpiled material and completed an estimate of tonnage. Their work concluded that there are 103,415 tonnes of material and assigned an average grade of 3.2 g/t Au and 288 g/t Ag and are referred to in their report as "probable" reserves.
The volume of the stockpile was estimated using a topographic survey of the top of the pile and the volume of the workings from historical mine plans. The grade was determined through their trench sampling of the stockpile.
Also in 1959, the CRM made an estimate of in-situ vein material based on their channel sampling program at that time. They reported 4,921 tonnes with an average grade of 5.4 g/t Au and 424 g/t Ag (CRM 1959).
In 2012 the Mexican Geological Survey, now known as “Servicio Geológico Mexicano" (SGM), again completed an estimate of tonnage and grade for the same underground stockpile. SGM classified this historical estimate into 25,600 “Certified Tonnes” and 71,228 "Uncertified Tonnes." The certified tonnes were established through trenching of the stockpile, and giving their results an influence of 5m in depth. They estimated the grade of this material as 1.67 g/t Au and 166 g/t Ag. They then extrapolated an additional 71,228 tonnes to the bottom of the stockpile, and refrained from assigning an official grade to that material.
In 2017, Vangold Mining's consulting geologist and QP Carlos Cham Domínguez completed a re-sampling program on the top of the stockpile consisting of 57 samples from 20 trenches (mostly historic with a few new trenches) and returned similar grades for these trench samples as reported by SGM. The Vangold trenches were made to an average length of 6.42 meters and averaged 1.75 g/t Au and 183.5 g/t Ag. *
The results from Vangold’s January 2017 sampling program confirmed the grades found by SGM in 2012, as most of the individual assay results - and the overall average grades - are close for both gold and silver values. The results from the CRM study in 1959, however, show considerably higher gold and silver values than either SGM's or Vangold’s sampling. CRM reported average grade of 3.2 g/t Au and 288 g/t Ag. The higher results in the 60 year old CRM study may ultimately prove to be correct as the stockpile in 1959 the of the top of the stockpile may not have been so covered or diluted by occasional falls of waste rock from the walls of the open stopes as they appear today.
* “All samples were collected, recorded, bagged and sent by Vangold’s consulting geologist to ALS Laboratory in Guadalajara, Mexico for sample preparation. Gold, silver and multi-element ICP analysis was completed at the ALS laboratory in North Vancouver, Canada. Rock samples were fine crushed (70% passing a 2mm screen), pulverized (85% passing a 75 micron screen) and a pulp split separated for assaying by a riffle splitter. 30 gram portion of each sample was assayed for gold by standard fire assay and a 10 gram split was analyzed for 35 elements by ICP method. Standard reference material and blank samples were inserted into the sample stream at a 5% insertion rate with pulped samples from the underground stockpile for quality control purposes. The results of the standards and blank samples were satisfactory. All data was collected with industry standard practices and assay results were verified by Vangold’s consulting geologist.”
04SURFACE STOCKPILE OF MINERALIZED MATERIAL
On the surface of the El Pinguico project is a large stockpile of material which originated as waste material from the El Pinguico shaft during mining from circa 1904-1913.
In 2012 a private company commissioned by the then owner of El Pinguico calculated the volume of the surface stockpile as 92,849.5 m3, with a surface of 15,769.40 m2. In January 2017, Findore S.A. DE C.V. (“Findore”), a private geological services company engaged by Vangold, dug 10 holes with a backhoe into the stockpile at different locations and different depths, taking two samples from each hole (one at the top and one at bottom). The samples confirmed there was no movement of economic values from the surface to the bottom of the stockpile due to weathering or erosion over time, with the average samples results as follows:
Top samples 0.62 gpt Au 80.6 gpt Ag 1.78 gpt AuEq
Bottom samples 0.43 gpt Au 61.1 gpt Ag 1.32 gpt AuEq
Based on the foregoing, Vangold estimates the surface stockpile comprises approximately 175,000 to 185,000 tonnes of material grading between 0.45 gpt Au and 67 gpt Ag (1.25 gpt AuEq) and 0.52 gpt Au and 70 gpt Ag (1.35 gpt AuEq). The potential quantity and grade of the surface stockpile is conceptual in nature, there has been insufficient exploration to define a mineral resource and it is uncertain if further exploration will result in the stockpile being delineated as a mineral resource.
The Guanajuato District is near the southern edge of the Mexican Central Plateau, where the northwest structures of the Plateau have been abruptly cut by the easterly trend of the Transverse Volcanic Belt. A few kilometres south of Guanajuato only Pliocene and younger sediments and volcanism crop out; to the north, northwest and northeast, the most common rocks exposed are Cretaceous calcareous sediments folded into open and tight northwest trending folds.
The district lies on the northeast flank of a poorly defined northwest-trending anticline (Wandke and Martínez, 1928). Normal faults parallel to the anticlinal axial trace have dropped the central portions of the anticline downward, and a younger, second set of normal faults formed a series of horsts and grabens trending nearly perpendicular to the axial trace.
The fault parallels to the anticlinal axial trace cuts rocks as young as late Oligocene and are mineralized with adularia giving a K-Ar date as 27.4 m.y. (Gross, 1975). Therefore, a late age is assigned to the faulting. This age corresponds well to the taphrogenic stage of the post Hidalgoan orogeny described by De Cserna (1960).
The oldest rocks of Guanajuato District are marine organic and calcareous black shales deposited in the Triassic through Cretaceous Jaliscoan sea (De Cserna, 1960). These are unconformably overlain by post orogenic continental red beds (Edwards, 1955) and Eocene and Oligocene andesitic and rhyolitic air fall tuffs. Other than alluvium and landslide deposits. The nearest outcrops of post Oligocene rocks, a basaltic cap at Cerro del Cubilete is about 13 kilometres southwest of Guanajuato.
LOCAL GEOLOGY OF EL PINGUICO
Outcrops in the area of the El Carmen-El Pinguico mine are of the Tertiary formations called Calderones and Bufa; host of the El Carmen-El Pinguico Vein. The oldest unit in these concessions is the Bufa Formation and, consists of rhyolites, tuffs and rhyolitic breccias. It has a light pink colour, thickness of approximately 500 m and hosts most of the mineralization of the El Carmen-El Pinguico vein. The Calderones Formation overlies the Bufa Formation and outcrops in the southeast portion of the mining district of Guanajuato. It consists of massive andesite, tuffs and andesitic breccias of green colour, and has a thickness of approximately 500 m. In the north there is a dike of rhyolitic composition - Figure 4.