Zenith Minerals (ASX:ZNC) has added a new 100% owned lithium brine project in Mexico to its portfolio, complementing its Arizona and WA lithium projects. The project has reported water samples grading 1.2-2.1% lithium and surface sediment results of 524ppm lithium, indicative of a lithium enriched source brine environment. Ground geophysics is planned, to be followed by drilling in 2017.
- New tenure (26,000 acres) staked over extensive system of salt lakes within an emerging lithium brine district at Zacatecas in central Mexico;
- Lithium brines to 2.1% lithium reported in regional water and surface sediment sampling program conducted by the Mexican Federal Government – Mineral Resource Council from solar evaporation ponds for salt production on adjacent salt lake (10km west of Zenith’s new tenure).
- These results confirm lithium enriched source brines are present in the district, as well as demonstrating that concentration of lithium by traditional solar evaporation methods is possible: Four water samples returned 1.2%, 1.4%, 1.4% and 2.1% lithium, these very high-grade lithium brines are similar to post-concentration brine feedstock to lithium brine production facilities;
- Initial, limited reconnaissance sampling by Zenith on salt pans covering the Company’s new Zacatecas tenure returned highly anomalous lithium in surface sediments up to 524ppm – comparable to and higher than those from competitor lithium brine projects in Mexico and the USA;
- Major land holding in potential new lithium enriched sedimentary basin. Local geothermal springs indicate active circulating hot waters capable of leaching lithium whilst interpretation of geological and aeromagnetic data indicate complex basement geology indicative of major faults capable of channelling and focusing lithium enriched geothermal fluids;
- and Ground based geophysical surveys are planned for mid-January prior to drill testing early in 2017.
Zenith Minerals Limited (“Zenith” or “the Company”) is pleased to advise that it has staked new 100% owned concessions (totalling 26,440 acres) over a new lithium brine exploration project in central Mexico. The region is generally known for its large scale silver mines and has excellent infrastructure. The new Zacatecas project adds to the outstanding lithium project portfolio assembled by Zenith over the past 6 – 12 months, including lithium brine, lithium pegmatite and lithium clay targets in Australia and the Americas (Figure 1).
Zacatecas Project Mexico
Zenith has staked concessions over salt lake brine targets in the Zacatecas area of central Mexico. Three areas; San Juan, San Vincente and Illescas (covering a total of 26,440 acres) have been applied for with Zenith to hold 100% interest through a Mexican subsidiary. Lithium brines to 2.1% lithium have been taken from small scale, salt production solar evaporation ponds on an adjacent salt lake located 10km west of Zenith’s new tenure. The samples were taken as part of a water and surface sediment sampling program conducted by the Mexican Federal Government – Mineral Resource Council. These results confirm lithium enriched source brines are present in the Zacatecas district, as well as demonstrating that concentration of lithium by traditional solar evaporation methods is possible.
Initial reconnaissance sampling by Zenith returned up to 524ppm lithium in surface sediments on the San Juan salt lake concession and up to 206ppm lithium at Illescas. These results are comparable to and higher than those from many competitor lithium brine exploration projects in the USA and Mexico (Figures 2 – 4 and Table 1). Local community members have advised Zenith’s field team that hot springs were present up until recently on its Illescas concession whilst siliceous sinters (rocks indicative of ancient hot spring out-flow zones) have been recognised in field mapping on the San Juan concession.
The conceptual deposit model for Zenith’s new Zacatecas lithium brine project is adapted from the known deposits being exploited by other companies in the USA, Chile, Bolivia and Argentina. Water-bearing formations or aquifer types range from deep volcano-sedimentary units within the valley-fill sequence that are saturated in lithium-enriched brine such as at Albemarle’s Clayton Valley operation in Nevada USA to near-surface salt lakes and ponds in the south American lithium operations. Amongst other important geological and hydrological criteria these lithium districts generally contain active hot springs or there is evidence of past geothermal activity such as the presence of sinters (silica rich deposits that occur at hot spring out-flow zones). Existing lithium brine operations have lithium resource grades ranging from 102 milligrams per litre (mg/l) to 1409 mg/l this is roughly equivalent to 80 to 1100ppm lithium. In most cases the lithium brine is pumped into surface ponds and the lithium is concentrated to percent levels by solar evaporation before final treatment in a processing plant to produce lithium carbonate or similar products commonly used by battery manufacturers.
The Zacactecas lithium brine project within the closed El Barril aquifer, with its thick sequence of Tertiary, Cretaceous, and Quaternary age clastic sediments, ash beds and evaporite deposits is prospective for lithium brines. In addition, low average annual rainfall and very high average annual evaporation rates means that traditional methods of solar evaporation of brines are a viable production method. This is also evidenced in the many artisanal table salt production facilities that exploit the brines on several of the salt lakes within this district.