SCHREYER AWARD – ENVIRONMENT Decommissioning of Gaspe Mines

Copper mining and processing went on at the Gaspé Mines in Murdochville, Quebec from 1952 until it closed in 2002. The operations included an open pit mine, an underground mine, two concentrators and a copper smelter with a sulphuric acid plant. The footprint of the mine site, including the tailings, is about 80 square kilometres, with around 50 kilometres of roads.

When Xstrata Copper Canada took over the plant in 2006, they began a $116-million undertaking to rehabilitate the site, which was carried out between 2007 and 2010. The Gaspé Mines rehabilitation project was the first decommissioning of a mining operation and copper smelter in Canada.

GENIVAR provided complete engineering, procurement and construction management services to Xstrata Copper Canada on the rehabilitation project. Genivar was also the main environmental consultant for the rehabilitation of both the mine site and the residential properties that were affected in the nearby towns of Murdochville and Gaspé.

The project included demolishing all the existing mine structures, and decommissioning the tailings sites. It also involved handling over 1,000,000 m³ of materials.

In order to improve the management of water on the mine site, over 6,000 metres of bypass channels were constructed to help protect against erosion from snowmelt and the heavy rains that are common to the area.

Most of the demolished mining buildings contained dust with metal concentrations exceeding current environmental standards, which posed a hazard for the demolition workers. Using Xstrata Copper Canada’s Sustainable Development Policy and Guidelines, Genivar applied a detailed health and safety program, and as a result no worker had to be removed from the site due to exposure.

The impact of the mine was not just on its immediate site. Airborne pollutants from the smelting operations over 50 years had affected soils in the town of Murdochville, and also in the nearby Sandy Beach area where copper concentrate arriving by boat or train was transshipped. A total of 855 residential, commercial and industrial properties were rehabilitated, which involved the removal of, on average, 30 centimetres of soil and returning the ground cover to its initial state.

A large number of certificates of authorization and other permits — 46 in total — had to be obtained in a short time frame from the MDDEP (Quebec’s Department of Sustainable Development, Environment and Parks).

The most environmentally-friendly approaches were taken at each step of the project. For example, a specialized firm was hired to treat hydrocarbon-contaminated materials on site using a biopile. The technology uses naturally occurring microorganisms and enhanced aerobic biodegradation to break down the pollutants.

Most of the 150,000 m³ of soils excavated from private properties was reused as cover for the mine tailing sites.

Also, the demolition contractors separated and recycled all the metal materials, and all concrete structures were crushed to a size that could be used for fill material in deep foundations.

An extensive communication program kept the public informed and individual meetings were held with over 500 property owners.

All the calls for tenders issued for the project contained an incentive clause encouraging the hiring of local labour. And despite ceasing its operations in Murdochville and Gaspé, Xstrata Copper Canada continued to promote the local economy by providing buildings, sponsoring events and making donations. cce

“The jury was unanimously impressed by the complexity and ethical awareness demonstrated by this private sector initiative: to develop and implement a health and safety program for the workers; demolish the dust-filled mining buildings; decommission the mine tailings; clean the contaminated soil; and dispose of the contaminants on-site. We hope that this project will set a benchmark for future mine decommissioning projects.”