Macarthur Minerals locates further Lithium in Nevada in the basin adjacent to Clayton Valley with surface grades up to 187 ppm Lithium and provides an update on ASX IPO offer for Macarthur Australia Limited

Macarthur Minerals Limited (TSX-V: MMS) (the “Company” or “Macarthur Minerals”) is pleased to announce that it has conducted an extensive near surface geochemical sediment sampling program at the Company’s Stonewall Lithium Project (“Stonewall Project”), located in Lida Valley, Nevada. The Lida Valley is the basin adjacent to the Clayton Valley, which hosts North America’s only producing lithium mine, Albemarle’s Silver Peak Lithium Mine. All 380 samples contained lithium with sediment assays ranging from 14.6 parts per million (“ppm”) lithium (“Li”) and up to 187 ppm Li, with 19 samples over 100 ppm. This sampling program confirms last year’s first pass sediment sampling program, that anomalous concentrations of lithium are present in the playa surface sediments of Lida Valley.
David Taplin, President, CEO and Director of Macarthur commented:
“Further confirmation of lithium at surface at the Stonewall Project, in the Lida Valley, a basin located very near to North America’s only producing lithium mine, is potentially significant; not only for Macarthur Minerals but it also emphasises the lithium potential of the Lida Valley. Deeper drilling into the basin and the brines is a priority to ascertain if the same lithium brine potential exists in the Lida Valley as has been discovered and extracted in the adjacent Clayton Valley.”
Results of Extensive Sampling Program
A United States mineral exploration company performed the extensive lithium sampling program for the Stonewall Project. The sampling program on the Stonewall Project for the purposes of collecting sediment samples for lithium was conducted during late April 2017.
The sampling program returned 380 sediment samples collected from depths of ~ 1.5 ft. (~ 45 cm) with grades ranging from 14.6 to 187 ppm Li. Samples were collected from a grid pattern on the playa (dry lake bed) surface, with a sample spacing of 200 meters (656 ft.) and from N – S oriented lines with a spacing of 500 meters (1640 ft.) between sampling lines (refer to Figure 1). All holes contained lithium with sediment assays ranging from 14.6 ppm Li and up to 187 ppm Li.
The highest value analytical results were from sample ‘21-3’ at 187 ppm Li and from sample ‘12–16’ at 159.5 ppm Li. The sediment samples were taken under chain of custody to the ALS Chemex lab in Reno, Nevada. The samples were analysed for 51 individual elements by Method ME – MS 41, which is an ultra trace level analysis using Inductively Coupled Plasma – Mass Spectrometry (ICP – MS) methods, with an Aqua Regia digestion. Figure 1 shows the location of the Stonewall Project claims over the majority of the playa, sample locations and lithium results.
Stonewall Project
The Stonewall Project covers an area of approximately 12,019 acres (48.64 square kilometers) and most of the playa in Nevada’s Lida Valley Basin (refer to Figure 2). The Lida Valley is located 32 miles (53 km) to the SE of the Clayton Valley Basin, which hosts the United States’ only producing lithium mine.
The Stonewall Project is located in an intermontane basin and is surrounded by tertiary volcanic rhyolitic rock units, which are anomalously high in lithium. These rhyolitic units are thought to act as a potential source rock for lithium in the Clayton Valley brines. The potential lithium source rock includes flows and tuffs that likely extend below the alluvial cover.
There are two clusters of anomalous sediments; one in the north and one in the south of the Stonewall Project playa. The higher Li values in the sediments are proximal to fault intersections revealed by bedrock outcrop patterns. The foot prints of the anomalous sediments defined by our sampling are on the order of 1.5 km (~ 5000 ft.) long by 0.5 km (~ 1600 ft.) wide.
The fault intersections comprise the bounding structural framework of the moat sediment zone of the Stonewall Volcanic Caldera (rhyolitic – now extinct). The Company’s preliminary interpretation is that leakage of Li rich geothermal solutions at these fault intersections probably enriched the moat sediments which were deposited alongside the faults when the volcano was active (~ 5 million years BP).
The Stonewall Project is located in the mining friendly Nye and Esmeralda Counties of Nevada and is serviced by excellent infrastructure with access to power, water, labour and is bisected by the Veterans Memorial Highway Number 95. The regional climate also favours natural and inexpensive evaporation for brine concentration and allows year-round work.
Next Steps for the Stonewall Project
Extensive sediment sampling program is now complete and the next step of exploration will be carried out by geophysical methods. A detailed gravity survey may be conducted. Once the results of the sediment sampling survey and potentially, a gravity survey are integrated and analysed, drill sites will be selected for detailed subsurface investigation of the project.
At present, the exact depth and composition of the sediments in the basin are unknown. Macarthur Mineral’s geological team expects sediments to be at least approximately 92 meters (300 feet) deep. A stock watering well located approximately 400 meters (a quarter mile) to the south of the claim block was drilled to a depth of approximately 92 meters (300 feet).
It is also expected, that potential aquifers similar in composition and thickness to the upper and lower ash aquifers in the nearby Clayton Valley will be encountered at depth. The ash aquifers in the Clayton Valley are thought to have been were deposited by continental scale volcanic eruptions from calderas located 150 kilometers to the West (90 miles) and 790 kilometers North West (475 miles) of the Stonewall Project area. Ash fall from these volcanoes was deposited in the nearby Clayton Valley 52 kilometers to the North West (31 miles) and most likely also in the basins of the Lida Valley, where the Stonewall Project is located. The Stonewall Caldera (located at the prospect), may have also contributed similar ash fall sediments to both Clayton Valley and in particular to the Stonewall Caldera moat feature. The ash aquifers are both a host for and a possible source for lithium brines in the Clayton Valley.
ASX IPO OF MACARTHUR AUSTRALIA LIMITED UPDATE
The Company also provides an update that it has extended the Australian Securities Exchange (“ASX”) Initial Public Offering (“IPO”) of Macarthur Australia Limited (“Macarthur Australia”) to issue between 25 and 50 million shares at A$0.20 to raise between A$5 – 10 million (“Offer”) to close on 30 June 2017 with an expected date for quotation on 12 July 2017.
Macarthur Australia has been meeting with potential cornerstone investors.
A copy of the prospectus and first, second and third supplementary prospectuses and application form is available to qualified investors at www.macarthuraustralia.com.

Source: www.macarthuraustralia.com