According to the film "Saving Mes Aynak," Metallurgical Group Corp. (MCC) and Jiangxi Copper are in the initial stages of building an open-pit copper mine 25 miles southeast of Kabul. The location is home to a walled Buddhist city that dates back 5,000 years.

According to the Afghan Ministry of Mines and Petroleum, the site is also home to the world's second-largest copper deposit. China is an importer of copper and a major global refiner of the industrial metal.

In 2007, under the administration of President Hamid Karzai, MCC agreed to pay Afghanistan $3 billion to lease the Mes Aynak area for 30 years.

MCC plans to extract over $100 billion worth of copper deposited directly beneath the Buddhist city, according to the documentary. Archaeologists are trying to save the site.

A spokesman for Afghanistan's Ministry of Mines and Petroleum, Zabih Sarwari, told CNBC that the project is slated to start after the completion of a feasibility study.

"I feel pity if they allow it," said Javed Noorani, formerly of the nonprofit Integrity Watch Afghanistan. "The World Bank, in collaboration with the Afghan government, tried to remove the heritage [site] to safety, but this act in itself is a breach of international standards and laws on archaeology."

About 2,300 items have been removed from the site to National Museum of Afghanistan, said Ministry of Mines spokesman Sarwari.

The residents of at least a dozen villages were permanently cleared out to make way for the mining work, according to the documentary, most of which was filmed in 2013.

"People are worried because they have been displaced without being consulted or their consent sought," said Noorani of Integrity Watch Afghanistan, who called the planned mine a "clear violation of Afghanistan's environmental and social impact assessment standards."

In the film, the deputy president of MCC, Zhengou Liu, claims those villagers were informed in advance, and says that "MCC has outsourced some jobs to Afghan companies and is providing jobs to Afghans."

Brent Huffman, the director of "Saving Mes Aynak," told CNBC that he's skeptical about that claim. "Chinese companies have a history of making big promises to third world countries," he said.

In December, CNBC reported that the Muslim fundamentalist Taliban, which has sought to retake control of Afghanistan since being ousted from power in 2001, was claiming it would not obstruct the copper project.

The Taliban itself has destroyed ancient sites in Afghanistan, on the grounds that they're blasphemous. Most notably, the terrorist group destroyed the famous Buddhas of Bamiyan in 2001.

That destruction drew global condemnation, and the ruins of the site are now a UNESCO World Heritage Site.

Mes Aynack would qualify as a Heritage site if the government of Afghanistan were to apply for that status, said Silk Road archaeologist and UNESCO advisor Tim Williams.

"This is an outstanding and complex archaeological landscape, with astounding quality of preservation," Williams said.