Mining Closure Plans: Your Right to Know!

Ontario Mining Act Fact Sheet. August 2005.

Download the Document:


Part VII – Rehabilitation of Mining Lands

In Ontario, a mining company cannot (re)commence mining operations until a cer- tified Closure Plan and associated Financial Assurance are in place. The requirements for a Closure Plan, including Financial Assurance, are set out in Part VII of the Mining Act and elaborated in Ontario Regulation 240/00 (Amended to Ontario Regulation 282/03) – Mine Development and Closure under Part VII of the Act.1

Mines that existed prior to 1991 when new legislation and regulation came into effect in Ontario have been required to prepare a Closure Plan and post Financial Assurance. Closure Plans are still outstanding (and being developed) for three exist- ing, operating mines.

In planning for closure, there are four key objectives that must be considered: 1. protect public health and safety;

2. alleviate or eliminate environmental damage;

3. achieve a productive use of the land, or a return to its original condition or an acceptable alternative; and,

4. to the extent achievable, provide for sustainability of social and economic benefits resulting from mine development and operations.2

Impacts that change conditions affecting these objectives are often broadly dis- cussed as the ‘impacts’ or the environmental impacts of a site or a closure plan. It is convenient to consider potential impacts in four groupings:

Physical stability – buildings, structures, workings, pit slopes, underground openings etc. must be stable and not move so as to eliminate any hazard to the public health and safety or to prevent material erosion of the terres- trial or aquatic environment. Engineered structures must not deteriorate and fail.

Geochemical stability – minerals, metals and ‘other’ contaminants must be stable, that is, must not leach and/or migrate into the receiving environment at concentrations that are harmful. Weathering oxidation and leaching processes must not transport contaminants, in excessive concentrations, into the environment. Surface waters and groundwater must be protected against adverse environmental impacts resulting from mining and pro- cessing activities.

Land use – the closed mine site should be rehabilitated to pre-mining conditions or conditions that are compatible with the surrounding lands or achieve an agreed alternative productive land use. Generally the former requires the land to be aesthetically similar to the surroundings and capable of supporting a self-sustaining ecosystem typical of the area.

Sustainable development – elements of mine development that contribute to (impact) the sustainability of social and economic benefit, post mining, should be maintained and transferred to succeeding custodians.