Orocobre Limited (ASX: ORE, TSX: ORL) (“Orocobre” or “the Company”) provides the following update on the brine sampling of diamond core holes CAU20 and CAU21 in the NW Sector of the Cauchari JV property located in Jujuy Province, Argentina.
The exploration program is being managed by JV partner Advantage Lithium Corp. (“Advantage Lithium”) (TSX Venture: AAL) (OTCQX: AVLIF) who hold 75% of Cauchari. Orocobre owns 33.5% of Advantage Lithium’s issued capital and 25% directly in the joint venture.
— These results from CAU20 and CAU21 demonstrate the Phase III infill
drilling and resource conversion program is on track to deliver Measured
and Indicated Resources by early 2019
— Systematic brine sampling completed in holes CAU20 and CAU21
respectively averaged 629 mg/l lithium and 4,537 mg/l potassium from
113-318 m depth and 607 mg/l lithium and 4,691 mg/l potassium from
125-265 m in the north of the NW sector
— Drill holes encountered predominantly sandy sediments and gravels that
are expected to have high drainable porosity and excellent permeability
to support high pumping rates
— Holes confirm the continuity of the brine body between previous drill
holes in the NW Sector CAU17, CAU18, CAU07 and CAU16
— Very low Mg/Li ratios of 2.1:1 and 2.2:1 respectively, and low SO4/Li
ratios of 24:1 and 23:1 respectively, similar to that demonstrated
during pumping of CAU07 – excellent for conventional brine processing
— CAU24, completed in the southern portion of the NW Sector, confirms that
brine resources continue over a 20 km distance north to CAU18 and are
generally contained in the permeable sand dominated units.
CAU20 NW Sector Drilling Results
CAU20 is a resource hole drilled in the northern part of the NW Sector between previous holes CAU07, CAU17 and CAU18. CAU20 confirms the high quality of the brine resource in this area with 629 mg/l lithium and 4,537 mg/l potassium from 113-318 m depth, with very consistent results throughout the hole and a maximum value of 702 mg/l Li. A total of 16 primary brine samples were taken with a bailer device and the results of two duplicate samples validate the values of the primary samples. Samples were taken at systematic 12 m intervals, considered an appropriate sampling interval, given the porous interconnected nature of the aquifer. QA/QC results are awaited from the secondary laboratory.
The brine samples have a very low average Mg/Li ratio of 2.1:1 low SO4/Li ratio of 24:1, similar to Advantage Lithium test production well CAU07. Results are similar to those of the adjacent Olaroz project of Orocobre and Lithium Americas Corp and Ganfeng in Cauchari. Similarity of brine characteristics across these properties confirms the Cauchari-Olaroz brine resource is very extensive and relatively homogeneous and very suitable for conventional processing.
The relatively permeable and sandy sediments in the NW Sector have displayed high drainable porosity test results and are expected to yield relatively high pumping rates, which is very positive for future brine extraction.
CAU21 NW Sector Drilling Results
CAU21 is a resource hole drilled in the northern part of the NW Sector between previous holes CAU07 and CAU16. CAU21 further confirms the high quality of the brine resource in this area with 607 mg/l lithium and 4,691 mg/l potassium from 125-265 m, also displaying very consistent results throughout the hole, with a maximum of 705 mg/l Li. A total of 11 primary brine samples were taken with a bailer device and two duplicate samples validate the values of the primary samples. Samples were taken at systematic 12 m intervals, considered an appropriate sampling interval, given the porous interconnected nature of the aquifer.
The brine samples have a very low average Mg/Li ratio of 2.2:1 low SO4/Li ratio of 23:1, similar to CAU07. The boron and calcium concentrations are also low and excellent for conventional brine processing.
CAU24 NW Sector Drilling Update
Hole CAU24 has been completed in the south of the NW Sector, intersecting a sequence of gravels and sandy sediments below a surficial clay unit and underlying salt (halite) unit. The porosity and permeability characteristics of these sediments are expected to be positive and consistent with previous observations in holes such as CAU15 and CAU16. Sampling has returned brine with positive characteristics. The results of the brine chemistry analysis will be announced when they become available.
Activities are underway for the installation of monitoring wells, pipelines and other infrastructure required to carry out 30 day pumping tests on test production well CAU07 in the NW Sector and CAU11 in the SE Sector. These pumping tests will provide additional information on aquifer characteristics as an input to the three-dimensional groundwater model that is being developed to estimate lithium reserves and a production schedule for the project. The pumping tests will be carried out during Q4 CY18.
Orocobre Managing Director Mr Richard Seville commented, “The Phase III exploration programme being managed by our partner Advantage Lithium has delivered further excellent results in the NW Sector. The joint venture continues drilling to increase confidence in the significant project resource base which will become the foundation of the Feasibility Study which is expected to be completed Q2 CY19.”