Some tailings, such as the Levack tailings are particularly difficult to remediate. The tailings contained a layer of pyrrhotite, an iron sulfide that produces AMD even more readily than pyrite. Freshly exposed pyrrhotite is so unstable, that it spontaneously combusts when exposed to the rain. The 40-hectare site also contained pyrite that had been so finely ground that it formed a kind of quicksand. This kept heavy equipment off the site and made it impossible to seed with grasses.

Barren as Levack seemed at first glance, it was in fact host to numerous plants and bacterial communities. Cattails already established in the damp ground on the banks of both the acid and alkaline streams provided seed stock that colonized much of the site after it was terraced to retain water. Chara vulgaris, another alga, introduced to the alkaline pond, quickly flourished (see BIOLOGICAL POLISHING). Dams were built to disperse the alkaline mine slimes throughout the acidic sites. The two waste products neutralized each other, allowing the development of a lush vegetative cover.

In 1984, Tom Peters, the agricultural director at INCO, invited Margarete to determine if indigenous plant species would colonize the Levack Tailings site, located north of Sudbury, Ontario. Peters was well known in the mining community for his success in coaxing domesticated species to grow on tailings with the help of prodigious applications of lime and fertilizer. This controlled erosion and ended the clouds of dust that had plagued Sudbury for years. Vegetative ground covers also reduce acid mine drainage by limiting the amounts of oxygen and moisture that seep into tailings.

Kalin was in the midst of a four-year study of uranium tailings and was convinced from observation that – given time and some help – indigenous plants colonizing tailings would create better covers than domestic species at a much lower cost. She had noted in her research that some plants, particularly cattails, thrive in both alkaline and acidic conditions by supporting bacterial populations in their root mass which create pockets of neutral pH.

Peters was interested in the concept, especially for its potential at Levack. There were two ponds on the site, one at each end of the pH scale. Acidic runoff had accumulated in an old quarry, while alkaline mine slimes, generated by the operating mine, had created an alkaline stream that pooled against the dykes surrounding the site.  Initially supported by Inco and the newly created Reactive Acid Tailings Program of the federal government, Kalin identified the indigenous vegetation growing on the site and began to look for ways to stimulate its growth.