Mr. James Anderson reports
VANGOLD REPORTS SUCCESSFUL BULK SAMPLE RESULTS AT THE EL PINGUICO SILVER AND GOLD PROJECT
Vangold Mining Corp. has released results from its 1,039-tonne bulk sample and metallurgical test of material from its El Pinguico silver and gold project, located seven kilometres south of the city of Guanajuato, Mexico.
Bulk sample and metallurgical test
As reported in the company's June 2, 2020, news release, Vangold has completed its bulk sample and metallurgical test, which consisted of delivering a total of 1,039 wet tonnes of mineralized material from its El Pinguico silver and gold project for processing at Endeavour Silver Corp.'s nearby Bolanitos mill.
Gold and silver recoveries
The material used for this test came exclusively from the company's surface stockpile of waste material, which was left behind when mining ceased at El Pinguico in 1913. The material has been exposed to the elements since that time and was therefore somewhat oxidized. Despite this, recoveries of gold and silver were very good, and may point to better recoveries in the future from less oxidized material located within the mine itself.
- Gold: 75.18 per cent;
- Silver: 60.36 per cent.
At times during the milling process the company observed even higher gold and silver recoveries -- up to 77.68 per cent for gold and 67.19 per cent for silver. The different grinding size and residency time within different circuits at the Bolanitos mill account for much of these differences. The entire process helped the company gain a better understanding of how these higher recoveries were reached and how they can be replicated in the future. The company may also pursue additional lab tests in order to replicate the higher numbers and potentially apply that knowledge at one of the local Guanajuato mills.
Concentrate ratio 232 to 1
The company delivered 1,039 wet tonnes to Endeavour Silver's mill, which when dried became 1,006 dry tonnes. With the help of Vangold's consulting metallurgist, Augustin Parra, professor of metallurgy at the University of Guanajuato, the company chose to use certain silica depressors as reagents in the milling process. This procedure created a very high concentrate ratio of 232:1, which is remarkable for the moderate-grade material used in the test and may have the effect of dramatically lowering the cost of transporting potential additional concentrates in the future.
After separating and storing a small amount of the concentrate, which the company will have on hand to conduct future analytical tests, the final product consisted of 4.265 dry tonnes averaging 132.0 grams per tonne gold and 6,661 g/t silver. Total recoveries from the final product credited to the company by Endeavour were 18 ounces of gold and 913 ounces of silver.
Vangold's surface stockpile contains an exploration target of 175,000 to 185,000 tonnes grading 1.25 to 1.35 g/t gold equivalent. These figures are conceptual in nature.
The head grade in the 1,039 tonnes of material sent to Endeavour Silver's mill had an overall recalculated head grade, after processing, of 1.23 g/t AuEq (using a 96:1 gold:silver ratio). This is within the range of historically derived estimates, which gives the company confidence that its calculations regarding the grade of its underground stockpile will be affirmed when it samples the bottom of the underground stockpile material.
This bulk sample was sent to Endeavour Silver's Bolanitos mill, located to the north of Guanajuato and approximately 28 km from El Pinguico. Though sample material was derived exclusively from the company's surface stockpile, the company anticipates that results from this test may have direct implications for the company's higher-grade underground stockpile material, and for the project as a whole.
Next steps, as described in the company's news release dated June 2, 2020
Clearing the bottom of the El Pinguico shaft
With data from this bulk sample now in hand, plans are being finalized for crews to begin clearing the bottom of the El Pinguico shaft. In the 107 years since mining ceased at El Pinguico, approximately 30 metres of debris have accumulated at the bottom of this shaft. The company plans to attach a hoist to its metal headframe currently in place above the shaft and begin removing this material. Once this material has been removed, crews will be in a position to do three things:
- Sampling the bottom of the underground stockpile: The underground (UG) stockpile consists of material that in 2012 the Mexican Geological Survey agency determined to be 174,500 tonnes in size. In 2017, Vangold conducted a trenching program at the top of the UG stockpile. This program resulted in a weighted average of all of the trench samples of 1.75 g/t Au and 183 g/t Ag. Once crews remove the material at the bottom of the El Pinguico shaft, Vangold will be in a position to properly sample the bottom of the UG stockpile, and determine whether the grade of gold and silver established by trenching in 2017 on the top of the stockpile extends to the bottom of the stockpile.
- Inspecting the No. 7 Sangria adit: Clearing 30 m of material from the El Pinguico shaft will allow crews to enter and inspect the mine's No. 7 adit -- also known as the Sangria adit. This adit may provide a potential safe and inexpensive haulage way to bring the UG stockpile material to surface for onward delivery to a nearby mill for processing. This is the company's preferred method to bring the UG stockpile material out of the mine; however, fully refurbishing the El Pinguico shaft is also a potential alternative. The decision on which of these possibilities the company will pursue will be made once the Sangria adit is entered and fully inspected.
- Sampling of the Colmillo stope: Once the El Pinguico shaft has been suitably cleared, it is anticipated that crews will be able to access and sample the Colmillo stope. This stope was a high-grade area within the El Pinguico mine prior to its closure in 1913. Examples of historic sampling from this area conducted in 1909 can be seen on page 5 of the company's corporate presentation, available on its website.
The El Pinguico project
El Pinguico is a high-grade gold and silver deposit that was mined from the early 1890s until 1913. Toward the end of that period it was mined exclusively by the Pinguico Mines Company of New York, whose shares traded on the Boston and New York stock exchanges. The mining was done principally from the El Pinguico and El Carmen veins, which are thought to be splays off the Mother vein, or Veta Madre.
The Veta Madre is associated with a megafault that outcrops for 25 kilometres and is the most important source of precious metal mineralization in the region. The Veta Madre may cross Vangold's property at depth, underneath the high-grade El Pinguico and El Carmen veins. Very limited drilling has been done on the property and no drilling has attempted to encounter the Veta Madre at depth.
Historic stockpiles of mineralized material exist on surface and underground at El Pinguico, which may potentially provide feed to one of several operational mills in the Guanajuato area.
Quality assurance/quality control procedures
Standard QA/QC protocols were not employed by Vangold during the sampling of the material sent for testing because the heterogeneity of the 107-year-old waste dump made it difficult to do cost-effective determinative sampling. However, in an effort to understand the potential gross grade of the material being sent to the mill the sampling methodology described below was used:
- Representative samples were taken with a trowel from material on a front-end loader prior to being deposited in the bed of a 20-tonne truck. One sample was taken from each of the truckloads during the course of the day -- averaging eight to 10 samples per day.
At the end of each day, all the material was crushed by hand to have one fine, quartered and representative sample with an average weight of three kilograms, which was then sent to the Platinum Corp. SA de CV assay laboratory in the city of Silao, Mexico.
The final grade of the composite dump sample can only be determined once the final head and tail grades have been calculated by Endeavour Silver's laboratory at the Bolanitos mill for the entire 1,039-tonne sample.
Hernan Dorado Smith, a director of Vangold and a qualified person as defined by National Instrument 43-101, Standards of Disclosure for Mineral Projects, has approved the scientific and technical information contained in this news release.
About Vangold Mining Corp.
Vangold Mining is an exploration company engaged in the exploration of mineral projects in the Guanajuato region of central Mexico. The company's flagship El Pinguico project is a significant past producer of high-grade gold and silver and is located just seven kilometres south of the city of Guanajuato, Mexico. The company remains focused on the near-term potential for development and monetization of both its surface and underground stockpiles of mineralized material from El Pinguico.
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