BRISBANE, Australia, April 17, 2018 /PRNewswire/ -- Orocobre Limited (ASX: ORE, TSX: ORL )("Orocobre" or "the Company") is pleased to provide an update on the brine sampling of diamond core hole CAU17 in the NW Sector of the Cauchari JV properties 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 29% of Advantage Lithium's issued capital.
CAU17 drilled in the NW Sector intersected extensive gravel and sandy sediments, similar to hole CAU18, which is located 2.6 km further to the east
Drilling has now confirmed the NW Sector contains sediments with relatively high drainable porosity and permeability which extend south from CAU17 and CAU18 through hole CAU07 to CAU16 and CAU15 as shown in Figure 1
Brine sampling in CAU17 averaged 571 mg/l Li and 4,488 mg/l K in three samples taken in the lower part of the gravel sequence between 177 m and 203 m depth. These samples have an average Mg/Li ratio of 2.3:1, comparable to the nearby Olaroz project and other drilling in the NW Sector
Diamond drill hole CAU14 in the SE Sector is currently at a depth of 445 m with the aim of evaluating the continuation of the deep sand unit in the SE Sector
The Cauchari resource estimate is now expected to be completed in mid-May
Phase 3 drilling will start during May with new drilling equipment being mobilised to site, targeting the deep sand-dominated units in the SE Sector
NW SECTOR - CAU17 Drilling Results
CAU17 was drilled in the NW Sector, 2.6 km west of CAU18 for which results were released on the 10th of April, 2018. CAU17 was pre-collared with surface casing cemented to a depth of 140 m through the shallow fresh / brackish groundwater of the Archibarca alluvial (gravel) fan that overlies the deeper brine in this area. Brine is estimated to extend from above 140 m depth to the base of the hole at 237.5 m depth. CAU17 intersected an extensive sequence of gravel and sand dominated units in drill core from 146 m to 210 m depth, with gravel and sand units intersected from surface in the pre-collar. A clay / silt dominated unit was encountered near the bottom of the hole between 210 and 237 m depth. Brine sampling in CAU17 was conducted with a bailer device and three samples were obtained within the gravel unit at 178, 185 and 203 m depth. The lithium concentrations ranged between 549 and 606 mg/l and averaged 571 mg/l lithium and 4,488 mg/l potassium. The Mg/Li ratio of these samples was 2.3:1, identical to the producing Olaroz project to the north.
Brine chemistry results from CAU17 are very positive and suggest brine with elevated lithium concentrations may extend to the base of the outcropping sediments on the west of the Cauchari salar.
The brine body defined to date in the NW sector extends over a distance of 14 km from CAU17 and CAU18 in the north to CAU15 in the south as shown in Figure 1. All diamond core holes in the NW Sector (CAU07 [completed as a rotary hole], CAU15, CAU16, CAU17 and CAU18) have intersected significant intervals of sand and gravel dominated units with a relatively high permeability that are expected to support relatively high pumping rates and facilitate future brine extraction.
Orocobre Managing Director / CEO Mr Richard Seville commented, "The exploration programme being managed by our partner Advantage Lithium continues to deliver very encouraging results. Drill hole CAU17 shows the continuation of high brine grades and attractive brine chemistry in the north of the NW Sector. Drilling in this area has now been completed for resource estimation purposes and following completion of drill hole CAU14 Advantage Lithium will deliver a new resource estimate for the project."
SE SECTOR - CAU12 and CAU13 Results
Results have been received from core holes CAU12 and CAU13 in the south of the SE Sector area. These diamond holes intersected a sequence of halite and clay dominated units that are interbedded with sand dominated units. Sand dominated units were intersected in CAU12 from 358 m depth to the base of the hole at 413 m, and in CAU13 from 407 m depth to the end of the hole at 449 m. These sand dominated units are thought to correlate with the sand units intersected in the base of rotary hole CAU11. The pumping test in CAU11 was carried out at a flow rate of 19 L/s as reported in February 2018.
Brine chemistry analyses from CAU13 averaged 435 mg/l lithium and 4,088 mg/l potassium over the interval from 39 m to 281 m depth; no samples were successfully obtained from the deeper sand unit. Brine chemistry analyses of CAU12 averaged 305 mg/l lithium and 3,048 potassium from the depth interval between 25 m to 169 m; no samples were successfully obtained from the deeper sand unit. The Mg/Li ratio of these brines averages 2.7:1 and 2.5:1 respectively, marginally higher than in holes further to the north. Additional deeper drilling is planned for the SE Sector to provide additional information on the deeper sand unit.
Diamond Drilling of CAU14
Diamond hole CAU14 has reached a depth of 445 m. Conclusion of CAU14 will complete Phase 2 of the work program at Cauchari and will be the last hole to be included in the upcoming resource estimate.
Phase 3 drilling will start during May 2018 with new drilling equipment being mobilised to site. This program will target further definition of the deep sand-dominated units in the SE Sector which are currently at depths beyond the capability of the current drilling equipment.
Competent Persons Statement The information in this report that relates to exploration reporting at the Cauchari JV project has been prepared by Mr Murray Brooker. Murray Brooker is a geologist and hydrogeologist and is a Member of the Australian Institute of Geoscientists. Mr Brooker is an employee of Hydrominex Geoscience Pty Ltd and is independent of Orocobre. Murray has sufficient relevant experience to qualify as a competent person as defined in the 2012 edition of the Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves. He is also a "Qualified Person" as defined in NI 43-101. Murray Brooker consents to the inclusion in this announcement of this information in the form and context in which it appears.
About Orocobre Limited Orocobre Limited (Orocobre) is a dynamic global lithium carbonate supplier and an established producer of boron. Orocobre is dual listed on the Australia and Toronto Stock Exchanges (ASX: ORE), (TSE: ORL). Orocobre's operations include its Olaroz Lithium Facility in Northern Argentina, Borax Argentina, an established Argentine boron minerals and refined chemicals producer and a 29% interest in Advantage Lithium.