The prospect of more diamond mining on the James Bay Coast has some raising questions about whether enough is known about the environmental impacts.

De Beers has started the environmental assessment process to potentially mine diamonds in an area near its existing Victor mine, known as the Tango Extension.

The company is still at the beginning stages of an environmental — and economic — assessment for the project, but it has caught the attention Anna Baggio at the Wildlands League.

Baggio is calling for a more comprehensive assessment, given that De Beers has identified more than a dozen other potential areas to mine.

“Let's look at all the effects of Tango, plus all of these other pipes all together, and look at … what this region [will] look like if De Beers exploits all of the pipes.”

Baggio is concerned that pumping water out of the mine pits in the James Bay Lowlands could release more mercury into waterways around the mine. More of another form of mercury, called methylmercury, could collect in fish, she added.

Mercury is a known contaminant in the area. Pollution from the atmosphere falls in rain and snow and collects in the muskeg.

“De Beers own monitoring shows that it is increasing in the river,” Baggio said.

But the environmental superintendent for the Victor Mine said monitoring has not shown a consistent increase in mercury levels.

"If there is any effects, they are very localized,” Brian Steinbeck said.

He noted there is one area close to the mine where higher levels of mercury have showed up, and the company is doing more research to figure out why.

Monitoring would continue if De Beers goes ahead with the Tango Extension, he added.