Going deeper poses challenges.

Kidd to employ latest technologies, massive refrigeration unit to meet challenges

Falconbridge Ltd.'s Kidd Deep, just north of Timmins, mine expansion will "stretch the envelope" of existing technology, says the project manager overseeing what will be the deepest base metal mine in the world.

At 3,220 metres below ground, the two phases of the Kidd Mine D No. 4 shaft development present some major engineering challenges such as greater risk of ground fall and warmer temperatures, as well as the logistics of bringing the mine into production in an economical fashion, says Steve Flewelling.

The $640-million expansion, regarded as one of the premiere mining contracts in the world, will extend the life of the Kidd Mine by 15 to 20 years and keep 600 miners employed.

"The economics of going deeper, if we didn't do anything, would only get worse," Flewelling says. "The hardest part is not so much in developing the ore body, but in developing the mine economically to meet our investment quicker."

To meet these challenges, the company is applying the latest technologies in ground support techniques with rock bolts and shotcrete, is installing some of the latest generation of automated and mechanized equipment and is bringing in some of the best mining experts in the world.

The 'D' shaft project also involves one of the deepest-ever applications of paste fill, a dry slurry mixture of tailings, sand, water and cement which is pumped down to backfill excavation sites after the ore is removed.

Falconbridge is also employing some cutting edge technology through state-of-the-art digital systems with instantaneous monitoring of all mobile equipment, enabling operators to know its exact location and status in a more comprehensive manner.

The company is spending about $40 million on mobile equipment, including the newest models of front-end loading scoop trains and 50-tonne dump trucks, worth about one million dollars each to haul off waste rock and ore.

The jumbo drill rigs automatically drill their rounds to blast rock, and mechanical rock scalers will scrape off loose rock from the ceilings and walls. All the equipment will have environmentally-controlled enclosed cabs for the operators.

To keep temperatures below the surface at a bearable working environment of 28 degrees C, a massive refrigeration unit and revamped ventilation system is being installed - a $43 million undertaking.

The massive drum hoists, which will be installed in the summer of 2002, will be taken underground in sections and reassembled at the head of the shaft at the 1410-metre level. The company is spending $140 million to build one production and two service hoists.

"These will be the largest underground hoists in the world" outside of larger surface hoists in South Africa, says Flewelling.

Cycling times to drill, blast, excavate, backfill and cure in drilling at the ore panel will be reduced by 37 per cent. The higher rate of production will trim operating costs at mine D from $42 to $35 per tonne.

Kidd mine manager Dan Gignac says the extension, which will be developed in two stages in preparation for its full commissioning in 2006-07, simply maintains the status quo in production capacity at a steady 2.4 million tonnes annually.

The mine, which was developed over the years in stages, was first developed as an open pit in the mid-1960s reaching an all-time high in production yield at 4.5 million tonnes during the 1970s.

Planning for the vertical extension to develop the reserve between the 6,800 and 10,000 foot level began in the early 1990s with an exploration program culminating in a feasibility study approved last July to start work on the project.

"We've mined out the majority of the material above, and now we're faced with spending capital dollars to develop the furthest part of the reserve," adds Flewelling, who is a former manager of mine operations in Sudbury. "This operation would cease in 2006-07 without this extension."

The first stake of mine D stretches production to 2015. The second stage extends it to 2023 before production tails off in 2024.

"We're going to be generating some production during the capital phase to offset some of the capital costs of the project," says Flewelling.

Cementation Skanska Canada Inc., a North Bay mining contractor, was selected from a bidder's group of seven international mining contractors to start sinking the shaft this summer. Their competitive bid and innovative proposal reduced the construction schedule by one year.

"For a project of this magnitude and length of time, (reducing the construction schedule by one year) is significant," says Dan Gignac, general manager of the Kidd Mining Division.

A second mining contractor, Ram Rising, a Timmins outfit and subsidiary of The Redpath Group, was chosen to sink the ventilation shaft and undertake the lateral development.

For the community and the region, the D shaft development will be a major stimulant to business. Falconbridge pegs the economic spinoffs for the community over the next six years in labour, rentals, equipment purchases and material amounts to $265 million. An additional $91 million will be spent in northeastern Ontario.

Gignac says that doesn't include the indirect spinoffs to hotels, restaurants and the service industry to accommodate the construction force expected to move into Timmins.

Falconbridge estimates the construction labour force on site for this year will be at more than 120, peaking at almost 220 during the highest period of construction activity in 2004.

"We support and encourage the contractors to employ as many local people as they can," says Gignac. "But based on the specialty skills, there's not a plethora of shaft miners sitting around doing nothing in Timmins. They've gone elsewhere and may have to be imported."