2.3 Mining activities

Ontario has over 6,500 abandoned mines with some 16,000 identified features that pose environmental, safety, and public health threats. Operating mines also present a number of serious environmental concerns, including acidic mine drainage, tailings, the metals extracted, and some of the products used for extracting and processing the metals. Mining for radioactive materials presents particular problems (see section 2.7).

What to look for on-site

Vividly coloured orange, red, or black seeps or staining, areas devoid of vegetation, and the absence of species sensitive to low pH are definite signs of problems. Contact a biologist for information about low PH-sensitive species.

Contaminants to test for

Liquid discharges: Definitely include the metal mined at the particular site in your analysis. Also include a wider heavy metal scan including: antimony, cadmium, chromium, cobalt, manganese, mercury, selenium, and silver. Other pollutants that may also be present: ammonia, cyanide, ethylene glycol, hydrogen fluoride, and sulphuric acid. The pH of the effluent can also be very important.

Groundwater, soil, and sediments may also be contaminated.

Mining guidelines apply to arsenic, copper, lead, nickel, radium 226, total suspended solids, and zinc. You may want to include these contaminants in your request for analysis.

Metal finishing plants have separate guidelines that apply to cadmium, chromium, copper, cyanides, lead, nickel, total suspended metals (TSM), and zinc.

Acts and regulations that may apply

Fisheries Act (see the Metal Mining Liquid Effluent Regulations and Guidelines and other sections)

Canadian Environmental Protection Act

Ontario Water Resources Act

Ontario Environmental Protection Act (MISA Regulation 560/94)