The glaciers of Chile are threatened not just by global warming, but by mining operations high in the snow-peaked Andes cordillera.

On July 24, Chile’s state-owned copper mining company Codelco, the world’s largest producer of the metal, proposed changes to a controversial $6.8 billion expansion of its Andina mine. Whether the new proposal gets the green light from environmental authorities could determine the fate of 26 glaciers in the central Andes, which form a watershed that supplies drinking water to the 6 million Chileans living in the country’s capital, Santiago.

Activists were not impressed. “Nothing has changed. Andina 244 will continue destroying glaciers,” Greenpeace Chile wrote in a response. In March, Chilean Greenpeace activists declared a “Glacier Republic,” a sovereign state covering 23,000 square kilometers of glaciers in Chile that already has over 15,000 “citizens,” to push adoption of a law to protect Chile’s glaciers. And on Sep. 27, two thousand people, many of them children wearing superhero costumes, marched to the presidential palace La Moneda, in Santiago, to urge president Bachelet to write glacier protection laws.

The revisions to Codelco’s project, dubbed Andina 244, came in response to concerns voiced by environmentalists and local authorities in more than 2,000 public comments on the project. But those revisions would do little to alter the mine’s direct impacts on the glaciers.

Codelco had planned to remove six so-called rock glaciers to get at copper ore under the earth; opponents also charged that dust from the project would damage 20 visible ice glaciers that extend along the cordillera. Under the revised project, the range of the open-pit mine was shifted so that it will require partial removal of five rock glaciers instead of six, but the difference in total area is negligible: 89.94 acres instead of 89.97 acres. Codelco also announced that its own research, completed at the request of government authorities, showed that dust from the expansion would not accelerate melting at the neighboring visible ice, or white, glaciers. (Typically, little or no ice is visible at the surface of rock glaciers.)

At least one scientist found flaws in the company’s modeling: Alexander Brenning, a glaciologist from the University of Waterloo in Ontario, who has spent many years studying Chile’s glaciers, said Codelco’s wind field data does not match data from meteorological stations in the area, which could skew its calculations of particle dispersion rates. Dust and particulate matter are known to accelerate melting of glaciers given that they darken the glaciers’ surfaces, causing them to absorb more heat from the sun. “You find subtle contradictions. According to their models, dust from their mine won’t affect white glaciers, but anecdotally they mention that you can sometimes see dust clouds from neighboring mine Los Bronces,” he said.

In the revised project, Codelco also proposed measures to protect water resources: it would recycle 65% of the water used at the mine and inject fresh water directly into a nearby river to compensate for loss of glacial meltwater. And the company promised to study and preserve glaciers that feed the area’s major rivers—Mapocho, Maipo and Blanco—over the life of the project, through 2058.

For the Chilean government, weighing water and ice against copper makes for a complicated calculus. Codelco is 100% owned by the state and provides 14% of the government’s revenues, making it a major lifeblood for the country, one of South America’s strongest economies. According to Codelco, Andina 244 would also generate 18,000 jobs over the next six years. The expansion of the mine is part of a larger revamp at Codelco that is apparently needed if the company is to maintain its position as the world’s number one copper producer. Profits were down by almost a third in the first half of this year due to a slide in global copper prices, according to Reuters. (Profit margins, though, are a very generous 40%.)

Some 31,000 glaciers span the Chilean side of the Andes cordillera, which represent 82% percent of all glaciers in South America. Among these are thousands of rock glaciers, which are quite different from the glittering blue ice sheets and jagged crowns and slopes of translucent white that most people associate with the term. Rock glaciers are glacier-like formations consisting of angular rock blocks, between which glacier ice is packed, but not visible. They are just as important to water reserves as white glaciers .

Despite a lack of good laws governing the country’s glaciers, Chilean authorities do have some bite when it comes to protecting them. In July of 2013, a Chilean court suspended the operations of Pascua Lama, a mine run by Canada’s Barrick Gold, after indigenous communities were able to prove that the company had damaged glaciers near the mine, violating its environmental permit.

“Environmental awareness in Chile has been increasing over the last 20 or 30 years,” said Brenning. “NGOs are getting stronger, and the environmental thoroughness with which different government bodies involved examine those projects has been increasing over the last decade, in particular the glaciology group of the Chilean water authority.”