The company's namesake hard rock global resource is now 39.2 million tonnes grading 1.09% lithium oxide for 1.04Mt of lithium carbonate equivalent, with an increase of 40% combined across both its Core and Central properties, with the addition of the first small resource at the Huffstetler property to the north-east.
The Core area remains dominant with 31.7Mt at 1.07%, with a new high-grade dyke being discovered in the east pit area as a key change. Over 95% of the Core resource is within 150m of surface.
At Central, 1.5km to the south, resources are now 5.16Mt at 1.2%, with 75% of that deposit within the top 150m. Central remains open, and is limited by the property boundary.
A maiden 2.31Mt at 0.91% has been declared at Huffstetler, which is about 1km from Core, and was based on 14 diamond holes for 2151m.
The inferred resource is open along strike and up-dip, and is again defined by the property boundary.
Around 55% of the total resource is now classified as indicated.
The company has five rigs conducting infill and exploration drilling at Core, with the aim of upgrading indicated resources, and it is and is considering additional holes at Central and Huffstetler later this year.
CEO Keith Phillips said the increase confirmed the company as the owner of one of North America's largest spodumene resources, and the only hard rock resource in the US.
"The expanded resource offers the potential for increased annual lithium production, something we will evaluate as we prepare our updated scoping study for release next month," he said.
It is also completing a feasibility study on an integrated lithium hydroxide project for later this year.
Piedmont is looking to develop a 160,000tpa operation producing 6% spodumene at a cost of US$168 million from 2022, potentially to be followed a year later by a 22,700tpa lithium hydroxide plant at a cost of $377 million.
Piedmont shares, which have traded between A6.5c and $1.14 over past year, were steady at A89.5c today, valuing it at $1.4 billion.
Piedmont recently raised $159 million in the US to list on the American Depositary Shares at US$70 each on the NASDAQ Global Select Market. Its shares there were up 4.8% at $68.88 in afterhours trade.
