Chile’s constituent assembly has begun formally debating motions for a new constitution, which is set to replace one dating back to the dictatorship of General Augusto Pinochet.

The assembly on Tuesday began what is likely to be a lengthy process, discussing plans to nationalise mining, the creation of a one-chamber Congress, water rights, and protections for Indigenous territories, among other issues.

“In this period we are going to see what is really going to remain in the proposed constitution,” said constituent assembly President Maria Elisa Quinteros, noting that the text would face a nationwide referendum planned for September.

The discussions come as Gabriel Boric, a 36-year-old leftist former student protest leader, is set to take over as Chile’s next president in March.

His ascendency to the nation’s highest office marks the country’s most dramatic political and social shift since its return to democracy in 1990.

The constitutional body is dominated by independent and left-leaning representatives

On the discussion list are water and property rights, central bank independence, and labour practices. Other themes include animal rights, feminist education, protection of the natural world, and the legalisation of cannabis.

The proposals will be debated in the coming months and will need approval by two-thirds of the delegates, some 103 votes.

If approved they would face a process of modifications before a second definitive vote to be included in the final text. If rejected they would go back to the commission to be revised or discarded.

The potential for sharp shifts in the country has caused some alarm among conservatives while also sparking jitters among investors and mining firms.

Quinteros sought to allay the fears, saying there had been lots of “misinformation” around the process and that the motions were at an early stage.

But those concerns have seen the process lose some support, with a survey by private pollster Cadem showing that the percentage of people who currently say they intend to vote to approve the new Constitution had fallen from 56 to 47 percent.

The proposals will be debated in the coming months and will need approval by two-thirds of the delegates

The constitutional body, elected last year, is dominated by independent and left-leaning representatives, some with roots in a 2019 protest movement that broke out over inequality in one of the region’s wealthiest countries.

Kenneth Bunker, director of consultancy Tresquintos, said this was an important moment for “concerns” to be raised to avoid “wacky” motions moving forward and undermining trust in the process.

But Bunker said he still thought the new constitution would eventually pass, though it would create a challenge for Boric’s new government.

“In the short-term, the government of Gabriel Boric, if this Constitution comes to pass, will have a real challenge to balance the social infrastructure with the political and economic situation in Chile today,” he said.