Rehabilitation of Kam Kotia Mine

Kam Kotia is a former Cu/Zn mine near Timmins, Ontario that had approximately 6 million tonnes of unmanaged acid generating tailings covering more than 500 ha.

Environmental impacts have been locally significant:

• acidic leachate
• dusting
• aesthetics
• physical safety
  

Location Map

The former Kam Kotia Mine site is located approximately 35 km. northwest of downtown Timmins (see map (PDF, 722 KB))

Historical Background

Mining History

• Principle exploration 1926-1928, Exploration shaft
• Mining 1943-1944 - 169,000 tonnes open pit (mining carried out on behalf of Wartime Metals Corporation, a Federal Government Agency.
• Mining 1961-1972 - 5,840,000 tonnes, mainly underground
• Total Production - 6.0 million tonnes @ 1.1% Cu, 1.17% Zn, 0.10 oz/tonne Ag

Ownership History

• Patented 1932 - Kam Kotia Porcupine Mines Limited (82.5% owned by Hollinger Consolidated Gold Mines Limited)
• Transferred 1966, Violamac Mines Limited - Kam Kota Mines Limited
• Transferred 1975, Robison Mines Limited
• Surface rights forfeit to Crown, January 1988
• Mining rights forfeit to Crown, March 1988

Tailings Disposition

• <1961 270,000 tonnes in unconfirmed area north of mill
• 1961 170,000 tonnes in South Unimpounded Tailings, SUT, area
• 1961-67 2.73 MT deposited in North Unimpounded Tailings, NUT, area
• 1967 Ontario Water Resources Commission, OWRC, required construction of dams to create North Impounded Tailings, NIT, area
• 1967 1.5 MT deposited in open pit
• 1968-1972 1.4 MT deposited in NIT

Pre-Rehabilitation Aerial View and Photos

Hydrogeology

• North and East seeps, with a pH of 2-3, drain NUT, east half of NIT and north half of plant site to the Kamiskotia River in the north
• South seep drains SUT, south half of NIT and plant site to Little Kamiskotia River in the south, which has a pH 0f 3.5 to 4

Senes' Conceptual Rehabilitation Plan

During fiscal 2000/01 Senes Consulting developed the following five-phase conceptual rehabilitation plan for the Kam Kotia Mine site. (see map below, links to larger version).  Funding for Phases "A" and "B" were from the Abandoned Mines Rehabilitation Fund:

Phase "A"

The construction of a Lime Addition Treatment Plant, as well as all of its required infrastructure, and the construction of a new NUT impoundment dam structure during 2001-2002 - final cost of $10.2 million.

Photos of Phase "A"

Phase "B"

Phase “B” involved the relocation of the SUT tailings to within the new NUT impoundment area during 2002-2003.  Upon completion of the work, more than 340,000 m3 of SUT tailings had been relocated and buffered with Envirolime.  Lime was also spread over the peat/soil surface in the SUT area to buffer residual acidity.  Final cost was $3.6 million.

Photos of Phase "B"

Phase "C"

Phase “C” involved the relocation and buffering of the unimpounded NUT tailings to within the new NUT impoundment area. However, due to the large “pond” of acidified, metal-bearing water that had collected within the NUT impoundment area, the 611,000 m3 of the NUT tailings that were re-located during the winter of 2003/04 were stacked around the perimeter of the impoundment area. Approximately 34,000 m3 of tailings remained to be re-located from the farthest edge of the NUT area and from the various seeps and creeks.

The NUT pond’s acidified, metal-bearing water was treated, As well, the stacked tailings whre relocated.

Photos of Phase "C"

Phase "D"

Once the contaminated water had been dealt with and the remainder of the NUT area tailings had been re-located, Phase “D” will involve the construction of the wet/moist NUT impoundment area cover. Expected completion of this phase is in 2010.

 

Phase "E"

Phase “E” involves the construction of an engineered aggregate “dry” cover over the NIT area, and will deal with the physical hazards on the mine site, including the thin crown pillar and the open pit. As Phases “C” and “D” could not be completed due to the contaminated NUT pond, the initial 2 layers of the Phase “E” NIT cover were built during the winter of 2004/05. The remainder of the Phase “E” work will be completed by 2009.

Photos of Phase "E"

More Detailed Information on Kam Kotia

• The Rehabilitation of Ontario's Kam Kotia Mine:  An Abandoned Acid Generating Tailings Site (PDF format, 421KB) - A paper presented by Chris Hamblin at the Sudbury 2003 - Mining and the Environment Conference

• The Rehabilitation of Ontario's Kam Kotia Mine:  An Abandoned Acid Generating Tailings Site (PDF format, 2.38MB) - PowerPoint presentation by Chris Hamblin at the Sudbury 2003 - Mining and the Environment Conference