Zenith Minerals (ASX:ZNC) has reported positve passive seismic results from the Company’s Wilson Flat lithium project in Nevada. The geophysical results, along with anomalous surface assays, confirm structures and architecture consistent with lithium-bearing brine deposit models nearby. Similar geophysical surveys are planned for the Company’s Spencer and Zacatecas lithium brine projects.
- Ongoing exploration at the 100% owned Wilson Salt Flat lithium brine project in Nevada, USA is providing encouraging results;
- Trial geophysical survey using passive seismic technique confirms structures and basin architecture consistent with lithium-bearing brine deposit models identified in the adjacent Clayton Valley lithium brine production area;
- Initial reconnaissance sampling by Zenith returned highly anomalous lithium in surface sediments – comparable to and higher than those from competitor lithium brine projects in the USA;
- Follow-up electrical geophysical survey now planned to detect presence of salt water aquifer capable of hosting lithium brine; and
- Following success of this initial geophysical trail at Wilson Salt Flat, similar surveys are in progress at Zenith’s nearby 100% owned Spencer lithium brine project and at the Company’s new Zacatecas lithium brine project in central Mexico.
Zenith Minerals Limited (“Zenith” or “the Company”) is very pleased to advise that a trial geophysical survey using the passive seismic technique confirms the initial interpretation of a deep sedimentary basin beneath the surface salt lake, where initial sampling by Zenith returned highly anomalous lithium values.
The Wilson Salt Flat Project is located in Nye County, Nevada 140km east from the lithium production area of Silver Peak- Clayton Valley. The Project is 100% owned by Zenolith and is located in the Railroad Basin (Figure 1). The property is comprised of 168 unpatented placer claims in a single claim block totalling 3,360 acres that were located in November 2016 to encompass highly anomalous lithium in surface sediment samples coincident with a salt lake and discrete gravity low interpreted to be a closed basin.
During December 2016 Zenith completed a passive seismic geophysical survey with the aim of confirming the sub-surface architecture of the basin beneath the surface salt lake at Wilson Salt Flat. Zenith’s consultants – Resource Potentials have now completed processing of the data collected during the survey and in conjunction with Zenith’s geologists have completed a geological interpretation which confirms the presence of a thick, sedimentary sequence bounded by basin margin faults (Figures 2 & 3). The geophysical modelling has identified structures and architecture that are consistent with the lithium-bearing brine deposit models identified in the adjacent Clayton Valley area.
Initial surface sediment samples taken from the salt lake surface by Zenolith are enriched in lithium up to 192ppm (ASX Release 16th December 2016) supporting the hypothesis of lithium brines being present in the sub-surface (Figure 3).
Wilson Salt Flat – Lithium Brine Exploration Model
The nearby Silver Peak operation in Clayton Valley is currently the only operational USA lithium project. Production by Albemarle Corporation formerly Rockwood Lithium, is facilitated through an extraction system that pumps groundwater enriched in lithium to surface solar evaporation ponds on the property. Evaporation of fluid from the ponds over a period of 12 to 18 months increases the lithium concentration prior to transfer of the concentrated brine to a processing plant for final product development. Tesla’s lithium ion battery production facility (Gigafactory) is under construction nearby, also in Nevada.
The conceptual deposit model for Zenith’s Wilson Salt Flat Project is adapted from the known deposits being exploited by Albemarle Corporation. Six different water-bearing formations or aquifer types have been identified in Clayton Valley. These are specific volcano-sedimentary units within the valley-fill sequence that are either saturated in lithium-enriched brine or contain salt or clay minerals with anomalously high concentrations of lithium. In addition, recent lithium brine drilling success by Pure Energy Minerals (TSX-V:PE) in the south of Clayton Valley provides an additional lithium brine host architecture model, whereby basin margin faults along the eastern boundary have a strong control on the host sequences and entrained lithium brines.
The geologic setting within the closed Great Basin, with its thick sequence of Quaternary age clastic sediments, ash beds and evaporate deposits is prospective for lithium brines. The geologic formations that compose the surrounding mountain ranges, specifically certain Tertiary-age volcanic formations, contain anomalous concentrations of lithium and are considered one likely source of lithium in brines and sedimentary layers similar to those in the Clayton Valley area.
The Wilson Salt Flat Project requires a groundwater exploration program designed to discover a reservoir of brine within the sedimentary host basin with economically viable concentrations of lithium. If warranted by brine presence and lithium concentration levels, additional more detailed studies will be necessary to determine the hydrogeological characteristics of the aquifer units for lithium production.
Geological, geochemical and geophysical similarities between Wilson Salt Flat and the Silver Peak- Clayton Valley lithium deposits being exploited by Albemarle as well as lithium brines recently intersected in nearby 2016 exploration drilling programs by TSX listed companies Pure Energy Minerals and Advantage Lithium Corporation present an attractive exploration target at both Spencer and Wilson Salt Flat.
Infill surface sampling along with ground based electrical geophysical surveying followed by drilling is the next steps in exploration of the Wilson Salt Flat project. Physical examination of the drill cuttings and laboratory analysis of water and sediments is the most cost effective way to determine the presence or absence of economic lithium deposits beneath the property. An initial drilling program is likely and will require permits through the United States Bureau of Land Management (USBLM) and the State of Nevada. The first two holes will be designed to test specific structural and stratigraphic targets identified by the geophysical surveys. Given success with these preliminary exploratory drill holes in finding brine aquifers and anomalous lithium contents, additional holes would be placed to expand on the information relating to basin hydrogeology, leading to resource estimation.