Asbestos is an umbrella term to identify a group of fibrous minerals composed of silicate. Asbestos is subdivided into two distinct groups, the serpentine group and the amphibole group. It is in the serpentine group that we find chrysotile, the only type of asbestos that has been mined in Quebec. Chrysotile is also found outside of the Appalachian Mountains, including the Outaouais, Laurentians and Nunavik west of Ungava Bay.

In the group of amphiboles, we find crocidolite, amosite, actinolite, anthophyllite and tremolite, among others. These types of asbestos have not been mined in Quebec, but can be found naturally (often in traces) in a few places.

Due to its thermal, chemical, and mechanical resistance, asbestos (especially chrysotile for which Quebec production was well established but also some crocidolite and amosite which come from imports, particularly Europe) was widely used in structures and materials.

Due to geological formations, asbestos is naturally present in regions that once mined asbestos, particularly in the regions of Thetford Mines, Val-des-Sources and northern Quebec. Mountains of mine tailings, called dumps, were left in these areas where some asbestos mines operated until the year 2010.

These dumps were formed over decades of operation and vary in composition and topography according to the period and technologies used, and the region. The characterization shows variations in their composition, shape, and grain size. It is possible to find machining residues that contain unrecoverable asbestos fibres, crushed rock and sand that may contain asbestos, and waste rock. In terms of their chemical composition, tailings contain, among other things, magnesium, silica, iron oxides and metals such as nickel, chromium and cobalt.

The main interest of the 800,000 tons of AMT now comes from their content of strategic and critical minerals (MCS) such as magnesium, nickel, chromium, cobalt, etc., which represent significant economic development potential. As AMT have already been mined, crushed and ground etc., efforts to recover the minerals of interest are mainly metallurgical in nature and are significantly reduced in terms of energy and resources to be used.

Projects to promote AMT have significant economic benefits for Quebec. In addition to these, AMT recovery projects also have undeniable environmental benefits. Indeed, the use of residues (as a new resource in a real circular economy loop, and the impact of these activities on soil asbestos removal and dumps) reduces the exposure of populations to fiber emissions in the environment in the medium and long term.