- El Oro, Mexico
- El Dorado, Western Mexico
- SDA Plant, Western Mexico
- Cocula, Western Mexico
- El Oro Tailings Opportunity, Mexico
El Dorado Historic MineEl Dorado Gold-Silver Project
The El Dorado Gold-Silver Project is located in the Pacific Coastal Plain, State of Nayarit, within a district of epithermal vein systems which is known to host high grade gold and silver in several veins. The El Dorado vein trend is the principal vein system within the property covering an area of 5 km x 3.5 km in size. Veining follows a general northeasterly strike dipping steeply to the NW. A continuous reef outcrop forms a ridge 1.5 kilometers ("km") in length. Additional discontinuous outcrops both to the NE and SW indicate a strike length of 3.5 km.
The El Dorado vein system has a history of small-scale mining from two veins. Mining in the area has been documented during the periods of: 1900 to 1927; 1965 to 1975; 1975 to 1983; and 1985 to 1990, often producing direct-to-smelter grade material. Most recently, from 1985 to 1990, material from three levels to a depth of 30 meters ("m") below the surface was shipped to the "El Venado" processing plant located near Ruiz, Nayarit, for toll treatment to produce a flotation concentrate. Historical metallurgical balance sheets from this plant indicate the grade of the material was in the order of 5 grams per tonne ("g/t") gold and 70 g/t silver.
Prospero Silver Corp. explored the El Dorado property between 2010 and 2011, through a series of comprehensive exploration programs which included historical data reviews, geological mapping, geochemical sampling, trenching and drilling. A total of 4,950 m were drilled in 28 diamond core holes to an average depth of 150 m, over a strike length of 440 m. The drilling intersected multiple steeply-dipping silicified mineralized zones extending from near-surface to the 150 metre drilled depth.
Significant results reported by Prospero on Dec 10, 2010 (available on El Dorado Reports page) included 16.17 meters grading 4.03 g/t gold, 204 g/t silver, 4.0% lead, and 1.75% zinc; and 2.32 meters grading 6.04 g/t gold and 140 g/t silver. The range of widths and grades of the holes within the central portion of the Hundido historical mine area were reported to range from 1.45 meters to 11.22 meters (true widths). The Company's Qualified Persons have not verified Prospero's drilling results as due to COVID travel restrictions, they have not yet been able to examine the drill core nor assay data and are therefore relying on data provided in News Releases filed on Sedar by Prospero in 2010 and 2011 and verified by their Qualified Persons.
Prospero also reported that the mineralized zone is 400 meters long and extends up to 180 meters at depth. Within the mineralized zone Prospero intersected grades ranging from 3.0 to 40.0 g/t Au and 57 to 500 g/t Ag over true widths that range from 0.52 meters to 11.2 meters.
To the Company's knowledge, a NI 43-101 compliant mineral resource estimate has not been completed for the El Dorado property, however in July 2011, Prospero conducted an in-house historical resource estimate based on their drilling described above as well as a review of summary cross sections, limited production documentation and other mine records, as well as results from samples of mine dumps, underground sampling (46 by Fresnillo) and 283 surface outcrop samples collected by both Prospero and previous explorers and exploiters.
Candente Gold believes that Prospero's Qualified Person ("QP") is very well qualified and that the parameters used to arrive at the historical resource estimate are relevant and reliable, however the categories used in the estimate do not appear to be compliant with CIM Definition Standards. The Company's QP cannot verify that a qualified person has done sufficient work to classify the historical estimates as current mineral resources and therefore the Company is not treating the historical estimates as current mineral resources. Historical reviews of the potential tonnes and the potential grades quoted below are conceptual in nature.
Prospero's historical resource estimate was calculated using polygonal resources in 10 blocks based on intersections from 10 holes covering/in the Hundido and Intermedia Veins, using a tonnage dilution factor of 25% and a specific gravity of 2.8. Metal equivalencies were based on a gold price of US$1,000 per ounce ("oz") and a silver value of US$20 per ounce.
Prospero's historical estimate for the Hundido and Intermedia Veins is 190,000 tonnes grading 7.0 g/t gold and 173 g/t silver containing a historical resource of 40,926 oz gold and 1,014,030 oz silver. The grades and tonnages attributable to each vein are as follows:
HISTORICAL ESTIMATE / MINERALIZATION INDICATED BY DRILLING
Vein True Width m Tonnes Gold Equivalent g/t
Hundido 2.3 89,000 7.01
Intermedia 8.3 91,000 15.17
Notes: 1. Polygonal resources based on intersections from 10 holes.
2. Tonnage reduced by 25% to allow for mining dilution and recovery loss.
3. Does not constitute Reserves under SEC Industry Guide 7 nor Resources
under current CIM Definition Standards.
Based on all of the existing exploration data and previous historical resource estimates to date the Company believes that a Conceptual Exploration Target within 150 metres of surface has potential for: 110,000 to 200,000 tonnes of material grading from 4.4 to 9.8 g/t gold and 113 to 239 g/t silver containing between 22,500 and 41,000 oz gold and 500,000 to 1,000,000 oz silver, with secondary credits from lead and zinc. This in-situ conceptual estimate of the potential tonnes and grade is contained in unmined portions of the veins as previously delineated. It does not include vertical extensions of the veins below 150 m nor along strike where the veins have been mapped for 3.5 km nor additional exploration potential. The potential quantity and grade described above is conceptual in nature, that there has been insufficient exploration to define a mineral resource and it is uncertain if further exploration will result in the target being delineated as a mineral resource.
The following longitudinal section by Prospero shows the drilling pattern along the El Dorado veinin the area of the Hundido and El Dorado mines, along with summary drill hole intersection grades and widths used in the historical resource estimation. (Prospero News Release dated June 22, 2011, available on El Dorado Reports page)
Significant data compilation, re-drilling, re-sampling and data verification may be required by a Qualified Person for the Company before the intersection widths and grades can be verified to be compliant with current NI 43-101 standards. The Company's QP has not done sufficient work to verify the above-mentioned intersections.
In addition to the data described above, exploration potential outside of the area of historical mining and Prospero's drilling is believed to be excellent based on the 3.5 km strike length of the vein structures as indicated by vein outcroppings, argillic alteration and silicification. Along this trend, potential exists for both high-grade veins and lower-grade bulk tonnage stockwork zones that have been observed to extend over tens of meters in width in both the hanging wall and footwall of the El Dorado vein system ("Magellan Gold Corporation, Form 10-K Annual Report US SEC dated Dec 31, 2018, File No. 333-174287"available on El Dorado Reports page). Both the northeasterly striking as well as east-west striking splits of the main structure exhibit structural complexity and potential for multi-meter wide precious metal mineralization. Anomalous base metal assays (100's to 1000's of parts per million lead, zinc and copper) are ubiquitous as evidenced by the common occurrence of visible galena, sphalerite and chalcopyrite in outcrop and dumps.
El Dorado lies 50 km south of the SDA Plant, 70 km north-northwest of Tepic, the state capital, and 180 km southeast of Mazatlan, Sinaloa. The project has excellent road and rail infrastructure.