Argentina Lithium has revealed the findings of its first exploration diamond drill hole at the Rincon West Project in Salta Province, Argentina, and records positive lithium results from brine samples collected over a 70m thick permeable interval with lithium grades ranging from 225 to 380 mg/litre.
The Rincon West project encompasses 2,470 hectares of the salar basin and is situated west of the adjacent Rincon Project, which is owned by Rio Tinto. Five exploration holes have been planned initially to assess the prospective brine targets that have been located with geophysics.
“The first hole at Rincon West has revealed a permeable 70m interval with moderate to high-grade lithium values. This validates our belief that the concentrated lithium brines mapped in the adjacent resources do extend beneath our property. We are continuing our exploration drilling to delineate this mineralisation with the aim of defining a mineral resource.” explained Miles Rideout, Vice President of Exploration.
Collecting brine samples
Brine sampling was achieved by utilising a single-packer sampling unit throughout drilling. A bailer was utilised on two occasions when temporary equipment failure prohibited sampling with a packer.
After the drilling was completed, certain intervals of the hole were re-sampled with a double packer system, allowing isolation of particular intervals. The packer sampling technique enabled the collection of brine samples at specific depths whilst closing the hole at the bottom and at the top of the interval.
Core logs and the observation of drill mud conductivity suggested that the hole entered the brackish-to-brine aquifer at a depth of around 45m. The original hole was cased from surface to 42m depth to stabilise the loose upper formation sediments. Sand, black sand, and gravel host formations were logged between a depth of 50m and 76.3m, with silt and traces of sulphates.
From depths of 76.3m to 127.5m, the core logs indicated interbedded sand and silt with sulphates. Meanwhile, gravels with sand were logged from 127.5m to 144m, where the drill entered ignimbrite exhibited varying degrees of fracturing and alteration. In regard to the young volcanos south of the project, drilling resumed to 300m, to ensure that deeper permeable sediment units were not present in the sequence in the area of RW-DDH-001. The hole was stopped in granitic igneous units representing the basement.
Further re-sampling endeavours
All core samples discovered in drilling have been retained for logging by the company and have been made accessible for successive laboratory evaluation of factors, including complete and efficient porosity, permeability, and other measurable qualities of the aquifer formation.
Samples of brine were submitted for evaluation to Alex Stewart International Argentina S.A., the local subsidiary of Alex Stewart International. Alex Stewart utilised the inductively coupled plasma optical emission spectrometry (‘ICP-OES’) analytical method as the for the primary constituents of interest, such as boron, calcium, potassium, lithium, and magnesium.
Field measurements comprised pH, conductivity, temperature, and density. The quality of sample analytical findings was monitored and evaluated with a protocol of blank, duplicate and standard samples contained within the sample sequence. Differences between original and duplicate samples and results for standards and blanks have been determined within the satisfactory range for lithium.
Argentina Lithium has an option to earn a 100% interest in the Rincon West project, as defined in the company’s September 28, 2021 press release.