Rio Tinto (ASX:RIO) shares are enjoying a Santa rally of their own this month. Here's why

The Rio Tinto Limited (ASX: RIO) share price has performed well during December so far.

Since finishing November trading at $93.50, the company's stock has gained 5.66%.

As of Wednesday's close, the Rio Tinto share price is $98.80.

Let's take a look at what might have helped boost the resources giant's shares lately.

What's driving the Rio Tinto share price lately?

The Rio Tinto share price has likely been buoyed amid news of two major lithium projects this month.

The first, the $3.3 billion Jadar project, is reportedly facing continuous challenges. However, Rio is set to acquire the other, the Rincon lithium project in Argentina.

Rio Tinto announced its intention to purchase the Rincon project for around $1.15 billion last week. The project is capable of producing battery-grade lithium and is located in the South American country's 'lithium triangle'.

Unfortunately, reports of the Jadar project aren't so encouraging. While Rio Tinto hasn't released news of the project to the ASX, it has been the subject of media speculation.

Earlier this month, it was reported that authorities in Serbia – where the Jadar project is located – had halted the project's approvals following major protests where locals voiced concerns about the mine's environmental impact.

Since then, the managing director of the company's Serbian subsidiary reportedly told a local media outlet that Rio Tinto intends to halt works at the project to engage with the local community.  

Also likely driving Rio Tinto's stock this month is the growing price of iron ore. According to data from CNBC, the price of the commodity is 18% higher than it was at the end of November.

The company also announced the successor of its chair in December. Rio Tinto's current chair Simon Thompson will step down from the role in May. Former McKinsey and Company global managing partner Dominic Barton will replace him.

Despite its December gains, the Rio Tinto share price is still in the red long term. Right now, it is around 14% lower than it was at the start of 2021.