Eye Catching Junior Exploration Projects Within the Mexican Jurisdiction

30th November 2021

 

Expanding on the previous article, examining the Mexican geopolitical landscape and some of the key players who operate the major mining projects within the Mexican jurisdiction.

We will now have a quick-fire round through some of those ever hungry juniors, operating within Mexico’s junior exploration sphere and their key projects.

Bacanora Lithium

For the first stop on our virtual tour examining the junior sector, let’s examine the hot projects of an interesting junior, dabbling in what must be the spiciest commodity of them all right now… lithium! The company Bacanora Lithium (LON: BCN) owns ten mining concessions covering approximately 100,000 hectares in the northeast of Sonora State in Mexico (Bacanoralithium.com). Seven of the ten concessions cover what is termed the Sonora Lithium Project, on which Bacanora published a feasibility study in 2018. The project has a measured plus indicated mineral resource estimate of over 5 Mt (comprising 1.9Mt of measured resources and 3.1Mt of indicated resources) of LCE (lithium carbonate equivalent). The feasibility study has established proven mineral reserves (in accordance with NI 43-101) of 1.67 Mt and probable mineral reserves of 2.85 Mt LCE. Globally, this project boasts one of the larger lithium reserves with the added benefit of being high grade.

The project area is underlain by Oligocene to Miocene age rhyolitic tuffs, ignimbrites and breccias of the upper volcanic complex of the Sierra Madre Occidental. This succession was subjected to Basin and Range extension and normal faulting during Miocene times that resulted in the development of a series of half-grabens. These half-grabens are locally filled with fluvio-lacustrine sediments and intercalated tuffs containing lithium-bearing clays. Quaternary basalt flows cover the basinal sediment-volcaniclastic succession. (NI 43-101 report, Bacanora Minerals, 2012).

The ore is hosted in the lithium-bearing clay units that make up a substantial component of the inter-volcanic sedimentary units. In the project area, lithium-bearing clays in the upper clay unit are believed to be predominantly hectorite (Na0.3(Mg, Li)3Si4O10(OH)2). Drill intercepts of the Li-rich zone within the upper clay unit average 11.38 m in length. This is equivalent to a true thickness of 10.69 m based on the inclination of the unit (20˚ ) and that of the drill holes (90˚ )(NI 43-101 report, Bacanora Minerals, 2012) report. The company plans to mine the prospect via the open pit method, using a combination of miners and trucks/shovels to remove the waste material. In 2021, the company drilled a suite of 12 holes which formed the basis for the feasibility study, intersecting notable quantities of LCE in several of the cores.

Bacanora, have this mining project fully permitted and boast a 200 years of resource life, producing between 17,000-35,000 tons per annum. (Bacanoralithium.com).

Figure 1: Cross-section through suite of DDH drilled in 2011, basis of feasibility study (Source: Sonora Li project NI -43-101)

Figure 2: Key assays from the 2011 drilling

Stepping away from the lithium game for a moment, let’s look towards the base metals market and Mexico’s most notable commodity, silver.

Discovery Silver

Discovery Silver (CVE: DSV), operates the ground encompassing one of the world's largest undeveloped silver resources (or so they hope!). Located on the eastern edge of the Sierra Madre Occidental mountains in the state of Chihuahua, the Codero project lies within the northern part of the Central Mexican Silver Belt, which hosts Mexico’s premier porphyry and carbonate replacement deposits.

Discovery picked up the ground in August 2019 and have been busy at work understanding the nature of the higher-grade zones within the mineralisation system on the Codero project. Discovery Metals draws clear parallels between the Codero project and the Newmont operated Peñasquito Mine (discussed in the previous article), citing the similar nature of the bulk tonnage of precious metals. (Discoversilver.com).

Figure 3: Discovery Silver drilling at the Cordero Project (Source, The Northern Miner).

The property scale geology is relatively simple. It consists of two northeast trending belts of mineralised Cenozoic igneous rocks hosted in Cretaceous carbonate sequences. The intermediate to felsic igneous intrusive and volcanic vent facies, felsic domes and diatreme complexes host the vein-type mineralisation along with the country rocks. A third intrusive/volcanic centre, the Perla Felsic Dome, Diatreme Complex is located 5 km south of the Cordero Porphyry Belt. Most historical mine workings and prospects on the property are centred on outcropping, narrow high-grade silver, zinc, lead, gold veins and some high-grade contract skarn and replacement mineralisation in the central part of the Cordero Porphyry Belt. (Cordero, NI-43-101, 2018).

In 2018, the former operators Levon Resources Ltd. conducted a NI-43-101 preliminary economic assessment, which included a mineral resource estimate based on 263 drill holes totalling 126.235m. An open pit mining geometry was utilised to attain the resource estimates (Figure). The mineral resource is for the currently defined Pozo de Plata Diatreme (Pozo), the Cordero Felsic Dome and the adjacent Porphyry Zone to the northeast along the strike of the Cordero Porphyry Belt.

Figure 4: Cordero mineral resource - 2018 (Source: Codero project NI-43-101)

More recently in 2021, Discovery Silver has been busy drilling, recently releasing results of their phase 2 drill program on the flagship Cordero project. This current set of holes is focused on upgrading resources for inclusion in a prefeasibility study planned for 2022. Definitely a project to jot down in your notepads!

Collar locations and key highlights from the drilling are shown in the figures below:

Figure 5: 2021 Collar Locations Cordero Project (Source: Discovery Silver September 30 2021 release)
Figure 6: Key intercepts from the phase 2 drilling in 2021.

GoGold Resources

Last but not least, another company which catches the eye this time around is GoGold Resources (TSE: GGD). Whilst not technically a junior by textbook definition, due to their inflated market cap, GoGold’s projects in Mexico are still in the preliminary phases and are very exciting! The Los Ricos property, in the state of Jalisco, has been the focus for GoGold Resources since they acquired it in March 2019. Los Ricos, consists of 22,000 hectares within 42 concessions, located roughly 100km from the city of Guadalajara. The company has split the property into two projects, Loc Ricos North and South which are separated by some 25km. In 2020, an initial NI 43-101 compliant resource estimate was conducted on the Los Ricos South project, followed by a PEA (Preliminary Economic Assessment) in 2021. The latter yielded a base case NPV (Net Present Value) of $295 million.

Figure 7: Los Ricos property location (Source: GoGoldResources.com)

The project area lies within the Hostotipaquillo mining district which overlies the intersection of two extensive calc-alkaline magmatic arcs, the older Sierra Madre Occidental volcanic province, and the younger Trans-Mexican volcanic arc (or Neo-Volcanic Belt) (GoGoldResources.com). The geology is characterized by late Oligocene to Pliocene volcanic and subvolcanic intrusive rocks deformed by a set of northwest and east-west trending normal faults. Oligocene and Miocene volcanics are primarily andesite and rhyolite flows, rhyolitic airfall tuffs, and rhyolite / dacite domes that have been partially covered by Pliocene to recent basalt flows. A northwest trending graben extends across most of the district, one of several which formed as a result of late Miocene to Quaternary tectonic depressions. The geological geometry of the district at the intersection of the Sierra Madre Occidental volcanic province and the Trans-Mexico volcanic arc form the regional west-northwest trending Zacoalco graben system. (GoGoldResources.com)

The Los Ricos South project is centred around the historical underground Ag/Au mine of Cinco Minas. Between 1914-1930, this mine produced 33.3 million ounces of silver and 235.5 million ounces of gold from vein workings (NI 43-101 report, 2020). The Cinco Minas Vein system at Los Ricos is a classic epithermal precious metal deposit, which exhibits at least three phases of quartz and sulphide mineralisation and deformation. The vein, up to 30 m in width, has been traced over 3.5 km on the concessions. Mineralisation consists of pyrite and chalcopyrite as the most abundant sulphides, with local concentrations of galena, sphalerite, argentite, native silver, miargyrite (AgSbS2), and other silver-bearing sulphosalts. (NI 43-101 report, 2020).

A mineral resource estimate based on 286 drill holes totalling 39,409 m is summarized in the table below based on the 2020 NI 43-101 report prepared by P&E Mining consultants. From this drilling compilation, 229 drill holes are diamond drill holes (totalling 34,877.5 m) completed by GoGold and 57 are reverse circulation holes (totalling 4531.8 m) completed historically. Los Ricos South contains 63.7 million ounces silver equivalent (“AgEq”) grading 199 g/t AgEq contained in 10.0 million tonnes, with a further inferred resource of 19.9 Moz AgEq grading 190 g/t AgEq contained in 3.3 million tonnes. The Mineral Resource is amenable to both open pit and cut and fill/longhole underground mining methods (NI 43-101 report, 2020).

Figure 8: Mineral resource estimate Los Rico South NI-43-101 compliant (Source: Los Rico South Ni-43-101 report).
Figure 9: GoGold Drilling in 2019 for NI-43-101 resource estimation on Los Ricos south project (Source NI-43-101 report, 2020)
Figure 10: Target vein location within the Los Riocs south project (Source NI-43-101 Report)

The Los Ricos North Project located 25km north of Los Ricos south was launched in March 2020 with drilling beginning in June 2020. Currently the Company is undergoing a 100,000m drilling program in 2021, and has 9 drill rigs operating at Los Ricos North at multiple targets including El Favor, El Orito, Casados, Mololoa, and La Trini. The El Favor and El Orito targets were initially drilled in September 2020 and January 2021 respectively.

Figure 11: Present drill sites and sample locations GoGold (Source: GoGold website)

Drilling at El Favor has shown four stacked zones of wide mineralisation starting from surface along 1000 m of the historic El Favor vein and workings. High-grade silver and gold close to surface were intersected near the surface, and wide zones of mineralisation mapped on surface continue down dip for close to 600m. GoGold is currently advancing this target towards mineral resource estimation with further drilling aimed at step out drilling to the east.

GoGold’s drilling in January 2021, on the El Orito target are the first holes ever testing this particular target, which lies 1.2 km west of the El Favor deposit. Drilling intersected epithermal hosted base metal, silver and gold mineralisation averaging 30m in width for more than 700m along strike and up to 300m in vertical depth. Base metal mineralisation has been observed at depth which is atypical for this area and so adds a “cherry” so to speak for the El Orito target. Company’s exploration team is mapping, sampling, and surveying with IP geophysics to potentially connect the two deposits (GoGoldResource.com)

The El Orito deposit may be unique in the Los Ricos district as it is the deeper part of the system where silver and base metals are present, while the other targets in the system to date have shown primarily silver and gold mineralisation. The known strike length of the El Orito – El Favor structure is now approaching 2,500 meters and is still open in both directions. The surface topography at El Orito is 400 to 500m lower compared to El Favor and is allowing the exploration team to see this large, mineralised structure over a vertical height of 750 meters when measured from the surface outcrops at El Favor to the intersections in the El Orito drill holes (GoGold news release 25.08.21).

Figure 12: El Favor and El Orito drilling 2020/21 (Source GoGoldResources.com)
Figure 13: IP Survey conducted over El Orito target area (Source GoGoldResources.com)

Other targets of note in the Los Ricos North project include the La Trini and Casados. GoGold’s initial drilling at La Trini in 2020, confirmed significant high-grade silver and gold mineralisation hosted in a flat lying zone which outcrops at surface and dips gently to the north. Tio date 96 drill holes have been drilled by GoGold on the property. Both impressive and encouraging results from the drilling late/early last/this year have further cemented La Trini as viable target for GoGold.

The company plans to explore further to the northwest and follow the trend of mineralisation into untested ground. Highlights include 61.4m of 204 g/t AgEq from 55.6 to 117.0m, consisting of 124 g/t Ag and 1.06 g/t Au in silicified and altered quartz rhyolite units included a high-grade intercept of 3.4m of 2,765 g/t AgEq, consisting of 1,694 g/t silver and 14.28 g/t gold within LRGT-20-070. A summary of the most recent drilling (LRGT-20-066 to LRGT-20-074) are shown below.

Figure 14: GoGold recent drill results from 2020 drilling of the La Trini target (Source GoGold news release 09.12.20)
Figure 15: La Trini Drill plan map and GoGolds plan for next suite of exploration holes on the target (Source GoGold news release 09.12.20)

Like El Orito, Casados is an untested target and GoGold’s exploration holes are the first holes within the vicinity. Again, the mineral is hosted in a vein system hosted in andesitic tuffs and exposed at surface, strike E-W and dip at 45˚ to the north. Historical mining of these veins inferred an average width of 1.5 m, however drilling has shown that the mineralising veins have a width of over 20 m. Secondary veining in the target area located in the footwall of a structure have also been discovered with grades equal to and sometimes better than the original vein. In some instances, the vein system merges to form a width of 56.5 m and with grades of 171 g/t AgEq (GoGoldResources.com). The table below shows the most recent drilling assays, released in August 2021. One notable drill hole, LRGCS-21-053, intersects 3,435 g/t silver equivalent (“AgEq”) over 1.0 m within 41.6 m of 312 g/t AgEq (GoGold news release 18.08.21). Quite exciting times indeed for GoGold, and ones most certainly to watch in the near term!

Figure 16: Casados recent drilling assays (Source GoGold news release 18.08.21)
Figure 17: Plan map of the Casados drilling (Source GoGold)

So there we have it, a quick fire run through a handful of juniors and their key projects within the Mexican jurisdiction. Whilst there are several other players operating within this space, those named above caught the eye this time around, due to their recent heightened activity on the ground, coupled with encouraging publicised results, a recipe always sure to tickle the potential investors taste buds!!


References

https://www.bacanoralithium.com/projects/sonora-lithium/

Bacanora Minerals (2012), Report on the Sonora Lithium Project (Pursuant to National Instrument 43-101 of the Canadian Securities Administrators), https://www.bacanoralithium.com/pdfs/NI-43-101-Report-on-Sonora-Lithium-Deposit.pdf

https://discoverysilver.com/

M3, (2018) NI 43-101 Technical Report Preliminary Economic Assessment Update on the  Cordero Project, for Levon Resources Ltd. https://discoverysilver.com/site/assets/files/5559/levon_-_cordero_-_tech_report_-_apr2018b.pdf

https://gogoldresources.com/

P&E mining Consultants, (2020), Technical report and initial mineral resource estimate (NI-43-101 & 43-101F1 compliant) of the Los Rico South project, Jalisco, Mexico, prepared for GoGold Resources. https://gogoldresources.com/images/uploads/files/LRS_NI43-101_Resource_20200822.pdf

GoGold Resources, (2021), GoGold Drills 1,197 g/t AgEq over 1.2m within 73.7m of 101 g/t AgEq at El Orito in Los Ricos North News Release. https://gogoldresources.com/images/uploads/files/2021_08_25_Orito.pdf

GoGold Resources, (2020), GoGold Drills 3.4m of 2,765 g/t AgEq at La Trini in Los Ricos North Contained Within 61.4m of 204 g/t AgEq, News Release https://gogoldresources.com/images/uploads/files/2020_12_09_Trini_69_to_74.pdf

GoGold Resources, (2021), GoGold Drills 3,435 g/t AgEq over 1.0m within 41.6m of 312 g/t AgEq at Casados in Los Ricos North, News Release https://gogoldresources.com/images/uploads/files/2021_08_18_Casados.pdf

Luke Holland

View posts by Luke Holland
Luke is an exploration geologist based in Ireland, graduating from University College Cork in 2017. Luke has worked for several exploration companies and consultancy firms within Ireland and is currently employed with Boliden at its Tara Mines Pb/Zn operation in Navan, Co. Meath Ireland. Supplementary to this, Luke is a council member for the Irish Association for Economic Geologists (IAEG) an organisation geared at the promotion of mineral exploration in Ireland. Luke’s love of all things rocks led him to join the Spotlight Mining writing team in November 2021.