Like other gold mines scattered throughout the Canadian Shield, one mine (which wishes to remain anonymous) situated close to the Quebec-Ontario border is in the process of environmental decommissioning.
The mine produced thousands of ounces of gold in its heyday and employed 140 people. Today it’s simply an environmental project.
“While decommissioning doesn’t put the local people back to work, cleaning up the site is a step in the right direction,” says Anthony Guido, an investor who has injected capital into the area. “The community appreciates that the land will be properly restored to its original state.”
Murray Demolition of Toronto, Ontario began this turnkey decommissioning project in July 2003. Before mobilization a series of events had to happen. A team of engineers met onsite to perform a waste minimization audit, an environmental audit and a decommissioning evaluation. With these three information resources in hand, a project schedule was prepared.
In this case the waste audit identified six main streams of material: re-usable machinery and equipment “as is”; re-usable machinery and equipment that needs rebuilding; recyclable metals (ferrous and non-ferrous); re-usable and recyclable wood; construction and demolition waste that is not recyclable (including asbestos); and, rubble, concrete and brick suitable for backfill or recycling.
The goal of this project is to minimize waste and divert as much as 92 per cent possible from landfill.
The environmental audit identifies three main environmental issues: polychlorinated bi-phenol (PCB) contaminated transformers, asbestos-containing material in various forms, and residual process material.
The decommissioning evaluation indicates that approximately 66 per cent of the equipment is suitable for reuse so an investment recovery program was initiated. Approximately 60 items are in the process of being sold, including rod mills and rod chargers, ball mills, compressors, and pumps. While many decommissioning projects usually only have local buyers interested in equipment, this project has also raised interest from worldwide buyers from developing-world mining companies since it was in good condition and still has years of life remaining. This aggressive program should reduce the cost of the project by 20 to 30 per cent.
In addition to the mining equipment, there were quite a few interesting architectural and historical relics onsite when the cleanup crew arrived and these were handled somewhat differently. An auction was held and the area residents were invited. The proceeds from the sale of these historical items were donated to the local community.
A five-week program was designed to initiate operation. First, asbestos abatement will be performed in accordance with provincial guidelines. The abatement calls for the installation of decontamination facilities for the workers, “negative air” filtration in the work areas, and comprehensive health and safety protocols. The PCB handling will be carried out simultaneously. Once these two main environmental abatements are underway the more traditional work is planned around the environmental program.
The demolition will be carried out using both traditional and progressive methods. While some of the buildings require the “smash and bash” old-fashioned techniques, other parts of this project require intricate demolition to be carried out using shear and breaker attachments to place selective cuts and source-separate materials as the buildings are demolished. With the high waste diversion target it is important for the team to be creative.
The first priority is the reusable or recyclable pieces that are not part of the investment recovery program. In addition to the main process equipment, there is other equipment that requires dismantling. Some of the pieces will be reused and the balance will be cut up and sent to a recycling facility. This will generate approximately 4,000 tonnes of ferrous scrap metal.
The workers will systematically strip the buildings and recover further metal waste; some pipe may be suitable for reuse but the majority will be prepared and sent to a recycling facility.
Scrap metal has value in most projects and the benefit in this particular one is that the metals market appears to have remained consistent with the time that the tender was received. An estimated 80 tonnes of specialty metals will be generated, made up of copper, stainless steel and aluminum. Rebar, used to reinforce the concrete, will also be removed during the next stage.
Other equipment will be sold for value subsequent to preparation. Residual cyanide product is present in some of the process equipment that will be sold for reuse. Prior to the sale, the equipment will be vacuumed out using standard and specialized industrial equipment under the control of trained environmental professionals under the terms of the health and safety plan.
The next stage of work will be the structural demolition of the buildings. John Deer 992s (as well as John Deere 450s and 550s) with 70 La Bounty sheer attachments will make quick work of the structures. Some wood material may be saved as it could be reused in the construction of protective hoarding on other project sites.
After this waste is separated and hauled away, there will be structural demolition of the concrete foundations and subsurface. The same heavy equipment will be used but the attachments will be different. “Breakers” and “concrete pulverizors” will be used to break up the denser material into “six-inch minus” pieces. Approximately 5,000 tonnes of this material will then be handled onsite and then utilized in final site grading. This segment will take between 30 and 45 days.
If the schedule is met the project will be complete in seven months, by January 2004. There will be some potential uses for this site but there are currently no plans in place.
James Sbrolla is a principal of Environmental Business Consultants, based in Toronto, Ontario. E-mail James at email@example.com