What happened Shares of start-up Piedmont Lithium (NASDAQ: PLL) popped more than 17% in early trading Thursday before giving much of that back and retracing to a much more modest 7.5% gain as of 12:55 p.m. EST. So what It's hard to say for certain what sparked today's share-price move at the lithium miner. On the one hand, Piedmont announced yesterday that it has begun "test work" on a spodumene concentrator pilot project. Piedmont will be aiming to transform 50 tons of mineralized pegmatite into spodumene concentrate containing at least 6% lithium oxide useful for the production of rechargeable batteries. These samples can then be provided to Pidemont customer Tesla (NASDAQ: TSLA) for further testing, preparatory to the latter's agreement to begin buying in excess of 50,000 tons of spodumene concentrate annually from Piedmont beginning after July 2022. Alternatively (or complementarily), Piedmont stock may be reacting to news about Tesla itself, reported yesterday by Electrek, to the effect that Tesla has roughly doubled its output at Gigafactory Shanghai to 23,000 cars produced in the month of October. Image source: Getty Images. Now what On the one hand, Piedmont is making progress toward its goal of being ready to supply Tesla's lithium needs when the companies' supply agreement goes into effect a couple of years from now. On the other hand, Tesla's production rate is ramping up, so it will need more (and more) lithium from Piedmont to support its growing production. Either way you look at it, the news today is good for Piedmont Lithium. 10 stocks we like better than Piedmont Lithium LimitedWhen investing geniuses David and Tom Gardner have a stock tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* David and Tom just revealed what they believe are the ten best stocks for investors to buy right now... and Piedmont Lithium Limited wasn't one of them! That's right -- they think these 10 stocks are even better buys. See the 10 stocks *Stock Advisor returns as of October 20, 2020 Rich Smith has no position in any of the stocks mentioned. The Motley Fool owns shares of and recommends Tesla. The Motley Fool has a disclosure policy.Source