The award was the brainchild of the Ontario chapter of the Canadian Land Reclamation Association (CLRA) and was created in partnership with the OMA and Vale Inco to encourage and recognize good mine reclamation work in Ontario, and to promote public awareness. It was named in recognition of Tom Peters, a founding member of the CLRA who pioneered tailings revegetation and land reclamation programs for Inco.
“He was a man before his time,” said Hamblin.
MNDM began proactive abandoned mine rehabilitation measures in 1991 with the proclamation of Part VII of the Mining Act. Under the legislation, mining companies are now responsible for submitting a closure plan for producing mines and advanced exploration projects, and executing it at the end of a project’s life. During the first three-quarters of the 20th century, environmental sustainability was not the priority it is today, and mining sites of bankrupt companies returned to the Crown. Reclamation planning now has to be done prior to the opening of a new mine, as well as for mines in operation prior to 1991.
Kam Kotia’s mining history dates back to the 1920s when copper and zinc were discovered on the site. In 1943, the Wartimes Metals Corporation urged a local mining company to mine the property as part of the war effort. An open-pit operation began, setting the stage for what later developed into a toxic soup of six million tonnes of unmanaged acid generating tailings covering more than 500 hectares of land. The mine closed in 1944, but was reopened from 1961 to 1972 as an underground operation that produced approximately 5.8 million tonnes of ore.
Three main tailings areas surround the mine site, covering about four kilometres across. Past aerial photographs captured the magnitude of destruction of every living plant, tree and blade of grass, leaving a lifeless no man’s land in its wake.
Hamblin, a man committed to and passionate about his work, equates it with a “living breathing beast” that at times seemed to take on a life of its own.
For decades, iron sulphides within the tailings mixed with oxygen and water, producing iron oxide and sulphuric acid, which leached into the ground, dissolving environmentally dangerous metals like zinc, copper and aluminum.
This deadly mix burned all life in its path, seeping into the Kamiskotia River system, killing aquatic life as well.
Fortunately, Kamiskotia Lake and its residents remained untouched.
“They didn’t have the awareness we have today and they certainly didn’t understand acid-mine drainage at that point,” Hamblin said.
The reclamation plan
In 1999, the provincial government announced a new, four-year $27 million abandoned mine rehabilitation fund to clean up Crown-held abandoned mine sites across the province. This allowed a more serious look at Kam Kotia. By 2000, a consultant had developed a conceptual plan with a projected cost of $41 million.
At the end of the day, a collective decision by MNDM, the Ministry of the Environment (MOE), and the Ministry of Natural Resources (MNR) was made to tackle the project. The option to reduce the footprint and seal off the tailings was chosen. By eliminating oxygen, oxidation would cease, thus, stopping the acid production.
The project was divided into five phases, designed to be able to stop at any phase with no progress lost. In 2003, funding was extended, allowing the project to continue, and in 2006, it was extended again so that all phases of the project would be completed.
In order to treat, contain and seal the tailings, the Ministry constructed a water treatment plant and related infrastructure, and a 3.2 kilometre impermeable impoundment dam within the North Unimpounded Tailings (NUT) site. A ditch with a clay liner was prepared in the South Unimpounded Tailings (SUT) area, described as the “kill zone,” to capture the ground water flow, which sealed off the contaminants.
“We’ve cut off the contaminant source and the vegetation is coming back,” Hamblin said.
Approximately one million cubic metres (m3) of NUT and SUT tailings were relocated to the new impoundment area buffered with “Envirolime.” But not everything went as planned. Two years of unusually heavy rainfall resulted in the new impoundment area filling with approximately 600,000 m3 (600 million litres) of contaminated water.
After extensive efforts to treat it “in-situ,” a decision was made to build a separate treatment plant and to neutralize the material with caustic and then filter it using large geotextile bags.
“This was a whole new application for these bags and it worked beautifully,” Hamblin said.
The engineered dry cover over the North Impounded Tailings area is nearing completion and will be seeded with shallow-root plant species in order to maintain a proper seal.
“Normally, we want natural species to come in, but with the cover, we have to prevent punctures going through caused by deep-root action,” Hamblin explained, adding it will have to be maintained over time.
The saturated sand cover over the tailings in the NUT impoundment area will be started this winter to eventually become a natural wetland.
Additional financial support came from the Ontario Mining Association and its members.
With 80 per cent of the site completed, the final cost is estimated to be about $60 million, not including an additional 50-year operation of the lime plant.
“We still have to complete phase E, which includes the rehabilitation of the physical hazards on the site, such as the main shaft, the open pit and the thin crown pillar,” Hamblin said, citing a projected completion date of 2010.
While the monstrous beast resides in its cage, Hamblin offered some words of hindsight: stay the course, diversify funding sources, build a contingency allowance into your bids to deal with the unforeseen, think outside the box, and be prepared for surprises from Mother Nature to negatively impact the project.